A lot of people may have heard from somewhere about the term “3G”. Be it from talks about the iPhone or subsequent developments in the field of mobile technology, 3G is becoming a norm for high tech cell phones today. But what exactly is “3G”?
3G or Third Generation is a generation of mobile phones and mobile telecommunications that conform to standards set by the International Telecommunications Union from the year 2000 onwards (officially referred to as International Mobile Telecommunications-2000 or IMT-2000). These include wireless voice services over a wide area, mobile internet access, mobile media services such as TV and video streaming and video calls.
3G differentiates itself from previous generations like 2G and 2.5G in that it should simultaneously allow both speech and data access services. This means that you should able to talk to someone on the phone while downloading an application from the internet. As such, 3G systems must have a minimum data access rate of 200 kilobytes per second. Most phones these days can easily leverage broadband connections of up to 28 megabytes per second.
3G technologies in India, though behind the rest of the world, has just begun to take off with efforts by Bharti Airtel Ltd and various partners such as Nokia Siemens, Ericsson and Huawei technologies to launch 3G services in India. How would this be beneficial? It would allow better cross-country communication and provide for internet on the go. This is usefully for accessing information from various parts in India where typical computers may be absent, but networks owned by major mobile network operators are available. It also helps India to keep pace with the rest of the world, as computing becomes more powerful yet more compact.
Cellular mobile services were initially offered using analogue radio technologies and these were considered as the first generation systems (1G). The definition of 2G was straight forward because analogue radio networks were replaced with digital ones (2G networks) in the 1990’s. Mobile phones and wireless devices using 3G, send and receive data much faster than second generation (2G) systems enabling many more features and applications to be possible. It enhances the services such as multimedia, high speed mobile broadband, internet access with the ability to view video footage on your mobile handset.
With a 3G phone and access to the 3G network you can make video calls, watch live TV, access the high speed internet, receive emails and download music tracks, as well as the usual voice call and messaging services found on a mobile phone.
In technical terms, 3G is a generic term covering a range of wireless network standards & technologies including;
CDMA – Wideband Code Division Multiple Access
CDMA2000 – Code Division Multiple Access 2000
UMTS -Universal Mobile Telecommunications System
EDGE – Enhanced Data for Global Evolution
HSPA – High Speed Packet Access including HSDPA and HSUPA
While 2G had evolved as a digital version of 1G analogue Radio network, its focus was initially into voice calls only. However over the period, due to requirement for internet connectivity when one is on the move, the technologies such WI-MAX, WI-FI etc were made part of 2G for mobile for internet/data service.
But with its mediocre data speed ranging from 56 kbps to 160 kbps, it was not serving the real purpose of internet usage. Whereas in the case of 3G, the technology itself is well oriented on data transfer in considerable bandwidth. This has made the concept of faster wireless connectivity a reality.
How does 3G work?
3G, or third generation networks, operate in a different way to 2G networks. When a call is made on 2G, a line is held open for the user’s conversation throughout the duration of the call. With 3G networks, the data sent across them is divided up into little ‘data packets’ which are reassembled in the correct order at the receiving end.
This smart encoding means more data can be sent and it is sent more efficiently. In addition, 3G handsets can be in contact with more than one base station at a time and this provides improved performances in voice quality and data rates.
3G is also called as “mobile broadband” because the evolution is similar to the difference between dial up internet and the always available broadband internet services.
The following are some of the services that could be provided through 3G
· Voice and Video calls
· Mobile TV
· Mobile Internet
· Mobile email
· Mapping and GPS applications
What is required for using 3G?
The first thing you require is a device (e.g. a mobile phone) that is 3G compatible. This is where the name 3G phone comes from – a phone that has 3G functionality. It’s nothing to do with the number of cameras or the memory it has.
3G phones commonly have two cameras since the technology allows the user to have video calls, for which a user-facing camera is required for capturing the image from the front.
You need to be subscribed to a service provider to get 3G network connectivity. We often call this kind of service a data plan or network plan.
Your device is connected to the 3G network through its SIM card (in the case of a mobile phone) or its 3G data card (which can be of different types: USB, PCMCIA etc.), which are both generally provided/sold by the service provider. Through that, you get connected to the Internet whenever you are within a 3G network.
3G in India
As such, Only BSNL & MTNL are providing 3G services in India that could be availed through 3G mobile phones. As a part of their 3G service BSNL and MTNL provide pure wireless internet connectivity for our PCs and laptops which could be availed through 3G Data card. In this 3G data card segment the private operators such as TATA Indicom, Reliance, MTS etc are also in the fray.
Check this page to find out the Tariff for 3G Services offered by BSNL
Presently the transfer rate for 3G networks is around 384 kbps (kilobits per second) and it will be between 128 and 144 kbps when you are out of city.
4G
We the people in India are yet to be familiar with devices that use 3G technologies thanks to the very slow speed in which our policy makers work for allocating 3G spectrum to the service providers. Unfortunately a new technology like 3G is yet too invented to increase the speed our beloved politicians and policy makers. Jokes apart, network specialists are on the way to launch another new mobile technology called 4G which would take the basics of 3G and yet amplify its quality.
Experts say once the stage is set, 4G would offer 100 Mbps to roaming mobile device globally and around 1 Gbps to a stationary device. Clearly, this could have wider implications including overwhelming wireless performances like enhanced video conferencing, streaming panoramic video and much more. The following interesting image could be found over internet to depict the difference between 3G and 4G
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Introduction to Mobile Devices
Today's mobile devices are multi-functional devices capable of hosting a broad range of applications for both business and consumer use. PDAs and the ever-growing category of smart phones allow people to access the Internet for e-mail, instant messaging, text messaging and Web browsing, as well as work documents, contact lists and more. Mobile devices are often seen as an extension to your own PC. Work done on the road, or away from the office can be synchronized with your PC to reflect changes and new information.
Types of Mobile Computing Devices
The term mobile device is used to mean a wide range of consumer electronics. Usually mobile device is used to describe the devices that can connect to the Internet. However, some will classify digital cameras and standard MP3 players as mobile devices as well. The category of mobile devices include the following devices, as well as others:
Personal Digital Assistant (PDA)
(sometimes called pocket computers) PDAs are handheld devices that combine elements of computing, telephone/fax, Internet and networking in a single device. A typical PDA can function as a cellular phone, fax sender, Web browser and personal organizer. Unlike portable computers, most PDAs began as pen-based, using a stylus rather than a keyboard for input. This means that they also incorporated handwriting recognition features. Some PDAs can also react to voice input by using voice recognition technologies. PDAs of today are available in either a stylus or keyboard version (called a datapad).
Examples of PDA Devices: Palm Pilot, Revo, Sony Clie, Hewlett-Packard Jornado, Casio Cassiopedia, Compaq iPaq, Toshiba Pocket PC
Smartphones
Smartphones combine both mobile phone and handheld computers into a single device. Smartphones allow users to store information (e.g., e-mail), install programs, along with using a mobile phone in one device. For example, a Smartphone could be a mobile phone with some PDA functions integrated into the device or vise versa.
Examples of Smartphones: Sony Ericsson, Palm Treo, Blackberry, Nokia T-Mobile Sidekick, Torq, Motorola Q, E-Ten, HP iPaq, I-mate,
Tablet PC
Tablet PCs are a type of notebook computer that has an LCD screen on which you can write using a stylus. The handwriting is digitized and can be converted to standard text through handwriting recognition, or it can remain as handwritten text. The stylus also can be used to type on a pen-based key layout where the lettered keys are arranged differently than a QWERTY keyboard. Tablet PCs also typically have a keyboard and/or a mouse for input.
Examples of Table PCs: Samsung Q1, Toshiba Portege, Fujitsu Lifebook, Motion Computing, IBM Thinkpad
Mobile Operating Systems (Mobile OS)
Like a computer operating system, a mobile operating system is the software platform on top of which other programs run. When you purchase a mobile device, the manufacturer will have chosen the operating system for that specific device. The operating system is responsible for determining the functions and features available on your device, such as thumbwheel, keyboards, WAP, synchronization with applications, e-mail, text messaging and more. The mobile operating system will also determine which third-party applications can be used on your device. Some of the more common and well-known Mobile operating systems include the following:
Symbian OS
Symbian OS has become a standard operating system for smartphones, and is licensed by more than 85 percent of the world's handset manufacturers. The Symbian OS is designed for the specific requirements of 2.5G and 3G mobile phones.
• Link: Symbian OS Web site
Windows Mobile
The Windows Mobile platform is available on a variety of devices from a variety of wireless operators. You will find Windows Mobile software on Dell, HP, Motorola, Palm and i-mate products. Windows Mobile powered devices are available on GSM or CDMA networks.
• Link: Windows Mobile Web site
Palm OS
Since the introduction of the first Palm Pilot in 1996, the Palm OS platform has provided mobile devices with essential business tools, as well as capability to access the Internet or a central corporate database via a wireless connection.
• Link: Palm OS Web site
Mobile Linux:
The first company to launch phones with Linux as its OS was Motorola in 2003. Linux is seen as a suitable option for higher-end phones with powerful processors and larger amounts of memory.
• Links: OSDL Mobile Linux Initiative
MXI
MXI is a universal mobile operating system that allows existing full-fledged desktop and mobile applications written for Windows, Linux, Java, Palm be enabled immediately on mobile devices without any redevelopment. MXI allows for interoperability between various platforms, networks, software and hardware components.
Feature iOS Android webOS Windows Mobile Windows Phone 7 BlackBerry OS Symbian MeeGo Bada Maemo
Company Apple Open Handset Alliance(Google) HP/Palm Microsoft Microsoft RIM Symbian Foundation Intel and Nokia Samsung Nokia
Current Version 4.0.2 2.2 1.4.5 6.5.3 Not yet released 6.0.0 9.5 1.99 1.0.2 5.0
OS Family Mac OS X/Unix-like Linux Linux Windows CE 5.2 Windows CE 7 Mobile OS Mobile OS Linux Linux Linux
Supported CPU Architecture ARM ARM, MIPS, Power Architecture, x86 ARM ARM ARM ARM ARM, x86 ARM, x86 ARM ARM
Programmed in C, C++, Objective-C C, C++, Java C C++ C++ Java C++ C++ C++ C/C++
License Proprietary EULA except for open source components Free and open source except closed source components Free and open source except closed source modules Proprietary Proprietary Proprietary Eclipse Public License Free and open source Free and open source
Package manager ? ? ? ? ? ? ? rpm+yum ? dpkg+apt-get
Default Web Browser/Engine Webkit Webkit Webkit Internet Explorer Mobile Internet Explorer Mobile Webkit Webkit Webkit Webkit (Dolphin Browser 2.0) Gecko
3rd Party Application Store App Store Android Marketplace App Catalog Windows Marketplace for Mobile Windows Phone Marketplace App World Symbian Horizon Samsung App maemo.org
Email Sync protocols supported POP3, IMAP, MAPI, POP3, IMAP, MAPI, POP3, IMAP, MAPI, POP3, IMAP, MAPI, POP3, IMAP, MAPI BES, BIS, Push e-mail POP3, IMAP POP3, IMAP POP3, IMAP, POP3, IMAP
Push Notifications Example Example Example Example Example Yes
Voice Recognition Example Yes Example Yes Yes Yes
Tethering Bluetooth, USB (carrier dependent), Wifi (with 3rd party software and "jail break") Wifi, USB, Bluetooth Wifi USB, Bluetooth, Wifi (with 3rd party software) USB, Bluetooth, Wifi USB, Bluetooth, Wifi (with 3rd party software microUSB, Bluetooth 3.0, Wifi microUSB, Bluetooth, Wifi
Audio Playback AAC (8 to 320 Kbps), Protected AAC (from iTunes Store), HE-AAC, MP3 (8 to 320 Kbps), MP3 VBR, Apple Lossless, AIFF, WAV AAC LC/LTP 3GPP, HE-AACv1 (AAC+), HE-AACv2 (enhanced AAC+), AMR-NB, AMR-WB, MP3 (Mono/Stereo 8-320Kbps constant or variable bit-rate, MIDI (MIDI Type 0 and 1. DLS Version 1 and 2., Ogg Vorbis, PCM/WAVE (8- and 16-bit linear PCM (rates up to limit of hardware), WAVE MP3, AAC, AAC+, AMR, QCELP, WAV MP3, WAVE, WMA, AAC+, MIDI, AMR, eAAC+, FlAC, OGG All (some require optional debian packages)
Video Playback H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format H.263, H.264 AVC, MPEG-4 SP MPEG-4, H.263, H.264 MP4, WMV, H.263, H.264, DivX, WMV, XviD, 3gp All (some require optional debian packages)
Turn-by-turn GPS 3rd Party software Google Navigation 3rd Party Software 3rd Party Software Bing Maps 3rd Party Software 3rd Party Software, manufacturers software Samsung LBS (Route 66)) free global Nokia Ovi Maps
Video out 1024 by 768 pixels with Dock Connector to VGA Adapter; 576p and 480p with Apple Component AV Cable; 576i and 480i with Apple Composite AV Cable 720p on select devices None None Device depending Nokia AV Out (PAL/NTSC)
True multitasking iOS4 only Yes ? Yes Yes Yes Yes Yes ? Yes
Support for hardware keyboard Yes[citation needed] Yes Yes ? ? Yes Yes Yes ? Yes
Videoconference front video camera Currently iPhone 4 and iPod Touch 4 Only Yes Yes ? ? Yes Yes Yes ? Yes
Can share images via Bluetooth with all mobile No Yes Yes ? ? Yes Yes Yes ? Yes
Skype Yes Yes[22] ? ? ? Yes Yes[23] ? ? Yes
Facebook IM chat ? ? ? ? ? Yes ? ? ? Yes
ssh ? ? ? ? ? Yes ? ? ? Yes
OpenVPN ? ? ? ? ? Yes ? ? ? Yes
Remote Frame Buffer ? ? ? ? ? ? ? ? ? Yes
Official SDK plattform(s) Mac OS X Multiplattform[24] Multiplattform Windows Windows Windows Windows GNU/Linux Windows GNU/Linux[25]
Feature iOS Android webOS Windows Mobile Windows Phone 7 BlackBerry OS Symbian MeeGo Bada Maemo
Types of Mobile Computing Devices
The term mobile device is used to mean a wide range of consumer electronics. Usually mobile device is used to describe the devices that can connect to the Internet. However, some will classify digital cameras and standard MP3 players as mobile devices as well. The category of mobile devices include the following devices, as well as others:
Personal Digital Assistant (PDA)
(sometimes called pocket computers) PDAs are handheld devices that combine elements of computing, telephone/fax, Internet and networking in a single device. A typical PDA can function as a cellular phone, fax sender, Web browser and personal organizer. Unlike portable computers, most PDAs began as pen-based, using a stylus rather than a keyboard for input. This means that they also incorporated handwriting recognition features. Some PDAs can also react to voice input by using voice recognition technologies. PDAs of today are available in either a stylus or keyboard version (called a datapad).
Examples of PDA Devices: Palm Pilot, Revo, Sony Clie, Hewlett-Packard Jornado, Casio Cassiopedia, Compaq iPaq, Toshiba Pocket PC
Smartphones
Smartphones combine both mobile phone and handheld computers into a single device. Smartphones allow users to store information (e.g., e-mail), install programs, along with using a mobile phone in one device. For example, a Smartphone could be a mobile phone with some PDA functions integrated into the device or vise versa.
Examples of Smartphones: Sony Ericsson, Palm Treo, Blackberry, Nokia T-Mobile Sidekick, Torq, Motorola Q, E-Ten, HP iPaq, I-mate,
Tablet PC
Tablet PCs are a type of notebook computer that has an LCD screen on which you can write using a stylus. The handwriting is digitized and can be converted to standard text through handwriting recognition, or it can remain as handwritten text. The stylus also can be used to type on a pen-based key layout where the lettered keys are arranged differently than a QWERTY keyboard. Tablet PCs also typically have a keyboard and/or a mouse for input.
Examples of Table PCs: Samsung Q1, Toshiba Portege, Fujitsu Lifebook, Motion Computing, IBM Thinkpad
Mobile Operating Systems (Mobile OS)
Like a computer operating system, a mobile operating system is the software platform on top of which other programs run. When you purchase a mobile device, the manufacturer will have chosen the operating system for that specific device. The operating system is responsible for determining the functions and features available on your device, such as thumbwheel, keyboards, WAP, synchronization with applications, e-mail, text messaging and more. The mobile operating system will also determine which third-party applications can be used on your device. Some of the more common and well-known Mobile operating systems include the following:
Symbian OS
Symbian OS has become a standard operating system for smartphones, and is licensed by more than 85 percent of the world's handset manufacturers. The Symbian OS is designed for the specific requirements of 2.5G and 3G mobile phones.
• Link: Symbian OS Web site
Windows Mobile
The Windows Mobile platform is available on a variety of devices from a variety of wireless operators. You will find Windows Mobile software on Dell, HP, Motorola, Palm and i-mate products. Windows Mobile powered devices are available on GSM or CDMA networks.
• Link: Windows Mobile Web site
Palm OS
Since the introduction of the first Palm Pilot in 1996, the Palm OS platform has provided mobile devices with essential business tools, as well as capability to access the Internet or a central corporate database via a wireless connection.
• Link: Palm OS Web site
Mobile Linux:
The first company to launch phones with Linux as its OS was Motorola in 2003. Linux is seen as a suitable option for higher-end phones with powerful processors and larger amounts of memory.
• Links: OSDL Mobile Linux Initiative
MXI
MXI is a universal mobile operating system that allows existing full-fledged desktop and mobile applications written for Windows, Linux, Java, Palm be enabled immediately on mobile devices without any redevelopment. MXI allows for interoperability between various platforms, networks, software and hardware components.
Feature iOS Android webOS Windows Mobile Windows Phone 7 BlackBerry OS Symbian MeeGo Bada Maemo
Company Apple Open Handset Alliance(Google) HP/Palm Microsoft Microsoft RIM Symbian Foundation Intel and Nokia Samsung Nokia
Current Version 4.0.2 2.2 1.4.5 6.5.3 Not yet released 6.0.0 9.5 1.99 1.0.2 5.0
OS Family Mac OS X/Unix-like Linux Linux Windows CE 5.2 Windows CE 7 Mobile OS Mobile OS Linux Linux Linux
Supported CPU Architecture ARM ARM, MIPS, Power Architecture, x86 ARM ARM ARM ARM ARM, x86 ARM, x86 ARM ARM
Programmed in C, C++, Objective-C C, C++, Java C C++ C++ Java C++ C++ C++ C/C++
License Proprietary EULA except for open source components Free and open source except closed source components Free and open source except closed source modules Proprietary Proprietary Proprietary Eclipse Public License Free and open source Free and open source
Package manager ? ? ? ? ? ? ? rpm+yum ? dpkg+apt-get
Default Web Browser/Engine Webkit Webkit Webkit Internet Explorer Mobile Internet Explorer Mobile Webkit Webkit Webkit Webkit (Dolphin Browser 2.0) Gecko
3rd Party Application Store App Store Android Marketplace App Catalog Windows Marketplace for Mobile Windows Phone Marketplace App World Symbian Horizon Samsung App maemo.org
Email Sync protocols supported POP3, IMAP, MAPI, POP3, IMAP, MAPI, POP3, IMAP, MAPI, POP3, IMAP, MAPI, POP3, IMAP, MAPI BES, BIS, Push e-mail POP3, IMAP POP3, IMAP POP3, IMAP, POP3, IMAP
Push Notifications Example Example Example Example Example Yes
Voice Recognition Example Yes Example Yes Yes Yes
Tethering Bluetooth, USB (carrier dependent), Wifi (with 3rd party software and "jail break") Wifi, USB, Bluetooth Wifi USB, Bluetooth, Wifi (with 3rd party software) USB, Bluetooth, Wifi USB, Bluetooth, Wifi (with 3rd party software microUSB, Bluetooth 3.0, Wifi microUSB, Bluetooth, Wifi
Audio Playback AAC (8 to 320 Kbps), Protected AAC (from iTunes Store), HE-AAC, MP3 (8 to 320 Kbps), MP3 VBR, Apple Lossless, AIFF, WAV AAC LC/LTP 3GPP, HE-AACv1 (AAC+), HE-AACv2 (enhanced AAC+), AMR-NB, AMR-WB, MP3 (Mono/Stereo 8-320Kbps constant or variable bit-rate, MIDI (MIDI Type 0 and 1. DLS Version 1 and 2., Ogg Vorbis, PCM/WAVE (8- and 16-bit linear PCM (rates up to limit of hardware), WAVE MP3, AAC, AAC+, AMR, QCELP, WAV MP3, WAVE, WMA, AAC+, MIDI, AMR, eAAC+, FlAC, OGG All (some require optional debian packages)
Video Playback H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format H.263, H.264 AVC, MPEG-4 SP MPEG-4, H.263, H.264 MP4, WMV, H.263, H.264, DivX, WMV, XviD, 3gp All (some require optional debian packages)
Turn-by-turn GPS 3rd Party software Google Navigation 3rd Party Software 3rd Party Software Bing Maps 3rd Party Software 3rd Party Software, manufacturers software Samsung LBS (Route 66)) free global Nokia Ovi Maps
Video out 1024 by 768 pixels with Dock Connector to VGA Adapter; 576p and 480p with Apple Component AV Cable; 576i and 480i with Apple Composite AV Cable 720p on select devices None None Device depending Nokia AV Out (PAL/NTSC)
True multitasking iOS4 only Yes ? Yes Yes Yes Yes Yes ? Yes
Support for hardware keyboard Yes[citation needed] Yes Yes ? ? Yes Yes Yes ? Yes
Videoconference front video camera Currently iPhone 4 and iPod Touch 4 Only Yes Yes ? ? Yes Yes Yes ? Yes
Can share images via Bluetooth with all mobile No Yes Yes ? ? Yes Yes Yes ? Yes
Skype Yes Yes[22] ? ? ? Yes Yes[23] ? ? Yes
Facebook IM chat ? ? ? ? ? Yes ? ? ? Yes
ssh ? ? ? ? ? Yes ? ? ? Yes
OpenVPN ? ? ? ? ? Yes ? ? ? Yes
Remote Frame Buffer ? ? ? ? ? ? ? ? ? Yes
Official SDK plattform(s) Mac OS X Multiplattform[24] Multiplattform Windows Windows Windows Windows GNU/Linux Windows GNU/Linux[25]
Feature iOS Android webOS Windows Mobile Windows Phone 7 BlackBerry OS Symbian MeeGo Bada Maemo
Search Engine Optimization Tutorial
by Kumar Anubhav
Part 1 - Why Search Engines Are Important To You . Learn how much traffic you could be getting.
Part 2 - The Basics. What's the difference between Yahoo and Alta Vista, and more?
Part 3 - How to get listed. What to do and what you can expect to happen.
Part 4 - How to improve your ranking. Just being listed isn't enough. Learn tricks to get a top ranking.
Part 1 - Why Search Engines Are Important To You
You've built your site. You've tested it. You're ready for business.
So where are all the people?
You need to get the word out about your great site, but with limited resources and no advertising budget, you need some way to attract visitors.
What can you do?
Try the No.1 way people find out about sites - Search Engines!
Surveys show that over 85% of internet users find new Web sites by using search engines. Other surveys show that after email, search engines are the most popular activity on the web.
Instead of blowing your limited resources on banners and ads galore, use search engines to send motivated visitors to your site. Click through rates on banner ads continue to drop, while search engine traffic is on the rise and growing everyday.
Search engine optimization (techniques to improve how your Web site ranks in the search engines) has been called the cheapest and most effective marketing tool available. Expect to pay professional firms that specialize in search engine optimization $2000 for a small site - $10,000 is common for big companies. If you are in an extremely competitive business, plan on shelling out $25,000 and up. Oh, and don't be surprised if you have to sign a six month or even a year contract. That's the norm for a professional shop.
You have an option to "do it in-house". With a little help from NetMechanic, you can do search engine optimization yourself, improve your site's search engine ranking, and save yourself a lot of money, frustration, and time.
Search engine traffic is the kind of traffic you want.
Why?
Traffic you receive from search engines is already targeted. Visitors arriving at your site from search engines have entered a keyword relevant to your site, so they are already interested in your product or service. This is the best source of potential customers you can have.
Search engines are the number one way users find new sites. Surveys show that over 85% of users rely on search engines to locate information on the Web. If you optimize your site to do well on the engines, then register your site with search engines, you should see increased traffic to your site.
Search engines are free to users and users know where and how to use them. One of the first things a novice to the Internet learns is how to use Yahoo (actually Yahoo is a directory, but we'll discuss the difference later).
Part 2 - The Basics
Before you can position your site to do well in the search engines, you need to understand search engine fundamentals.
A search engine is a giant database that lists sites on the Internet. You access the database when you enter keyword searches and receive a list of relevant sites.
Search sites are the Internet's Yellow Pages.
Think of a search engine as a giant, automated version of the yellow pages. If you need information on "party planning" from the yellow pages, there are several steps to retrieving it.
Go to the yellow pages and look under the alphabetized subject list for "party."
Note the subcategories: "party planning" "party - children's", "party - rental equipment", and so on.
Examine the companies listed under "party - planning" and decide which company best meets your needs.
You can repeat this process online using a search engine.
Search Engines Versus Search Directories.
People use both search engines and directories without ever realizing there is a difference between the two.
Directories (Yahoo, LookSmart) have human editors who review web pages, rank them, and then organize them into categorized lists with brief descriptions. The categories and descriptions are based on submissions, but are edited by professional editors (real people in the loop reviewing the sites being submitted).
Search Engines (AltaVista, Excite, Google) have automated programs called spiders that index sites and score pages based on proprietary guidelines. There is no human judgment involved. Search engines index all the information on all the Web pages they find. The indexes are generated automatically, based on the words and phrases that are found on Web pages.
What is a Search Engine?
Search engines send automated computer programs (called robots or spiders) to crawl the Internet in search of Web pages. Basically these spiders follow links to travel from URL to URL. When they visit your Web site, the robot indexes (or records) the text of your page or pages (if it is a deep crawling spider) and stores it in the search engine's index. Later, when a user enters a search query at the search engine's Web site, the search engine scans Web pages in its index for pages that provide the best match.
In theory, the search engine spider is supposed to be able to find all the sites on the Internet. However, since new sites are being added daily, it's risky to assume that the spider will find you. Expedite the process by submitting your URL to the search engines.
Not knowing the difference between a directory and a search engine can burn you!
What is a Directory?
Unlike the automated search engine process, each entry in a directory is first reviewed by a human being. You submit a short description to the directory for your entire site, or editors write one for sites they review. A keyword search will only look for matches in these descriptions, so be careful how you describe your site. Techniques to receive a high search engine rating will not work with a directory. While good content is necessary for search engines, both good content AND visual appeal are mandatory in human-edited directories. Remember, manual review takes time!
The typical time lag between free submission of a site and its actual listing in Yahoo is five months. You can speed up the process at some directories, but expect to pay for that service. This trend will probably continue.
Yahoo's Business Express Program, offers express guaranteed consideration of your commercial Web site within seven (7) business days.
Looksmart moved to an exclusive pay for listing scheme - all new submissions must pay to have their site reviewed.
Open Directory Project is a free directory. (Hint: If you get your site listed here, it will help you later in Google.)
When you submit to a directory, do it by hand and take your time. You need to impress human reviewers with your site so high-quality content and design are critical to your success.
Search Engine and Directory Hierarchy.
There are literally thousands of search engines on the Internet, but naturally you're most concerned about your ranking on the high-traffic sites. Some of the smaller search engines may not bring you a lot of traffic, but your listing gives you another source of links (which can help in your overall link popularity building).
If you can do well on the sites listed below, you will probably do well on others too.
Top Search Engines
Google
AltaVista
Lycos
Teoma
Overture
Top Search Directories
Yahoo
LookSmart
Open Directory
Zeal
Part 3 - How to get listed
Don't wait to be discovered! Submit your URL directly to the search engine or directory.
Search Engine submissions.
There are two ways to submit to search engines and directories, manually or using an automated submission tool. Here is a summary of both methods.
Manual Submission - Use the Add URL form from the search engine site itself. This way, you have absolute control over where your site is submitted. However, this process is that it is a very time consuming and labor intensive activity. Some search engines bury their Add URL form so far down in the site that one wonders if they are intentionally trying to thwart potential applicants.
Automated Submission Tool - Fill in the data once and the tool automatically submits your URL to multiple engines. It is a fast, easy one step process and you only have to fill in the data forms once.
There are several features you should look for in an automated submission tool.
The number one item of importance is to make sure the submission tool does not submit to directories. If you look down the list of places the tool submits and you see directories listed, leave and do not look back! You can be assured that NetMechanic's Search Engine Starter only submits to search engines.
The second thing to look for in an automated submission tool is to find one that allows you to pick and choose which engines to submit to. If you are doing well in one engine, but not in another, you may want to submit to the search engine where you need improvement and not submit to the engine where you are doing well. Again, NetMechanic's Search Engine Starter provides the user the flexibility to submit any page on their Web site to their choice of 28 different search engines.
Find a submission service that monitors search engine spam. Because most submission services submit to many search engines, you may receive spam email by some of the smaller engines that occasionally sell their email addresses.
Note: It is not the submission tool company that is selling the email addresses, it is the search engines themselves. NetMechanic's Search Engine Starter allows you to use an alternate email address when submitting your site. Additionally, NetMechanic monitors the search engines it submits to and purges spam-abusive engines from the submission list.
Bottom Line:
Submit your site to directories by hand. Save time by using a submission tool to submit to search engines.
How often do I submit?
Your best strategy is to submit weekly until your site gets listed. Check your listing frequently. If your site disappears suddenly, you may be the victim of a search engine database omission. Search engines frequently have multiple versions of their databases and they aren't always in sync. You may be listed in one version of their database and not in another. Your only recourse is to resubmit your site.
To see if you have even been picked up in a search engine, go to the search engine's site and do a search with your company's domain name as the search query.
Directory Submissions.
Submitting to a directory is a much more involved specialized process. Don't do it in a rush and don't use an automated submission tool. The better submission tools, like Search Engine Starter, don't submit to directories.
How long does it take to get listed?
These times vary with search engines and directories. The search engines will optimistically report a very short time, but most sites get listed within the following times:
Google 4 - 6 weeks
Lycos 4 - 6 weeks
WiseNut 6 weeks
The reality is that most search engines and directories are very backlogged and slow to get listings added to their databases. Don't be surprised if you experience waits much longer than these. As mentioned earlier, you may wait over 5 months to see your site get listed on Yahoo!, if it gets listed at all.
We recommend that if your site isn't listed within the time periods above, that you resubmit your site to the search engine where you are not listed.
Is being listed in the search engines good enough?
Unfortunately no.
A listing won't automatically increase your traffic. A good ranking may. You want to be listed on the first three pages of the search engine results page. Most web surfers aren't patient enough to look more than the first 20-40 listed links. In fact there is a considerable drop off just going from the first to the second page.
Part 4 - How to improve your ranking.
How do search engines rank pages?
Search engines use a ranking algorithm to determine the order in which matching web pages are returned on the results page. Each web page is graded on the number of the search terms it contains, where the words are located in the document, and other criteria that changes frequently.
All search engines have a different method of ranking. That's why you might rank number 1 on one engine and number 25 on another. Robots look for relevance and rank results on a secret ever-changing algorithm. Some look at TITLE, some look at META tags, some look for link popularity. Search engine optimization means optimizing the Web site for the best possible positioning based on the page's keywords and description.
NetMechanic's Search Engine Power Pack has a search engine optimization package that will walk you through the whole optimization process. NetMechanic has numerous experts who have conducted extensive tests to help identify what techniques work to better your ranking in the search engines. Additionally, we have identified what can get you into trouble with search engines.
General tips to get a good ranking.
1. Create a good site with good content.
This is critical, especially as search engines grow in sophistication. If your site contains worthwhile material, users will return to your site and will recommend it to others. Other sites will link to you - which will in turn help you by improving your link popularity.
2. Pick keywords visitors will actually use on a search engine query.
If you have keywords that are very competitive, consider narrowing your focus to improve results. The keyword "horse" will return thousands of responses and may not place you near the top, while "Appaloosa" is more focused and targeted to a particular query.
Consider using a keyword phrase instead of just one keyword. Visitors to search engines use phrases to narrow their searches. For example, instead of using a keyword like "horse" that would return too many responses, use a more specific keyword phrase like "Alabama Quarter horse."
Brainstorm a good list of list of keywords. Tap into other people - a fresh perspective can help uncover words you may have missed. This keyword analysis article offers some useful tips on brainstorming.
Don't just guess at which keywords are popular, get quantitative feedback using the Keyword Popularity tool included in Search Engine Power Pack. Remember, if you pick the wrong keywords, all your optimization will be wasted. See story on Keyword Selection.
3. Include keywords in your TITLE tag.
Pages with keywords appearing in the TITLE are assumed to be more relevant to the topic than those without.
4. Use keywords in META Keyword and Description tags.
Using META tags will not hurt you in search engines that don't use them, and they can definitely help you in search engines that do index them. While they are not as important as the TITLE tag, META tags can give you the edge over your competition since most web sites don't even use them.
5. Use your keywords throughout your page.
Search engines will check to see if the keywords appear near the top of a web page, such as in the headline or in the first few paragraphs of text. They assume that any page relevant to the topic will mention those words right from the beginning.
6. Have a good keyword density on your page.
Keyword density is derived by dividing the frequency of that word by the total words on the page. Frequency is a major factor in how search engines determine relevancy. A search engine will analyze how often keywords appear in relation to other words in a web page. Those with a higher frequency are often deemed more relevant than other web pages. This can turn into a balancing act as too high a density can be considered spam by some engines. Usually you are safe if your keyword density falls between 1 - 5 %.
7. Continually work on improving your link popularity.
Listings on popular Web sites can increase your traffic significantly. They do this in two ways:
They give potential visitors multiple paths to your Web site.
They can increase your ranking in search engines that use link popularity as part of their formula.
Most search engines use link popularity as relevance criteria. For example, the Google search engine (not their new directory) is based almost entirely on link popularity.
Summary
Success with search engines and directories is not one magical thing you do specifically. It is the culmination of your whole strategy. It is a time consuming, labor intensive activity with great rewards.
Bottom Line:
Use Search Engine Power Pack at least once a month to help you get more traffic from the search engines.
NetMechanic's Search Engine Power Pack is a search engine optimization power house. It's a five tool bundle that can help you improve your search engine ranking and bring more traffic to your site. Power Pack walks you through the whole search engine optimization process. From selecting your most effective keywords and building META tags, to optimizing your pages for peak search engine performance, to submitting your pages to the search engines of your choice and to tracking your site's performance in the search engines over time. NetMechanic has the one stop solution that will greatly improve your search engine performance.
Part 1 - Why Search Engines Are Important To You . Learn how much traffic you could be getting.
Part 2 - The Basics. What's the difference between Yahoo and Alta Vista, and more?
Part 3 - How to get listed. What to do and what you can expect to happen.
Part 4 - How to improve your ranking. Just being listed isn't enough. Learn tricks to get a top ranking.
Part 1 - Why Search Engines Are Important To You
You've built your site. You've tested it. You're ready for business.
So where are all the people?
You need to get the word out about your great site, but with limited resources and no advertising budget, you need some way to attract visitors.
What can you do?
Try the No.1 way people find out about sites - Search Engines!
Surveys show that over 85% of internet users find new Web sites by using search engines. Other surveys show that after email, search engines are the most popular activity on the web.
Instead of blowing your limited resources on banners and ads galore, use search engines to send motivated visitors to your site. Click through rates on banner ads continue to drop, while search engine traffic is on the rise and growing everyday.
Search engine optimization (techniques to improve how your Web site ranks in the search engines) has been called the cheapest and most effective marketing tool available. Expect to pay professional firms that specialize in search engine optimization $2000 for a small site - $10,000 is common for big companies. If you are in an extremely competitive business, plan on shelling out $25,000 and up. Oh, and don't be surprised if you have to sign a six month or even a year contract. That's the norm for a professional shop.
You have an option to "do it in-house". With a little help from NetMechanic, you can do search engine optimization yourself, improve your site's search engine ranking, and save yourself a lot of money, frustration, and time.
Search engine traffic is the kind of traffic you want.
Why?
Traffic you receive from search engines is already targeted. Visitors arriving at your site from search engines have entered a keyword relevant to your site, so they are already interested in your product or service. This is the best source of potential customers you can have.
Search engines are the number one way users find new sites. Surveys show that over 85% of users rely on search engines to locate information on the Web. If you optimize your site to do well on the engines, then register your site with search engines, you should see increased traffic to your site.
Search engines are free to users and users know where and how to use them. One of the first things a novice to the Internet learns is how to use Yahoo (actually Yahoo is a directory, but we'll discuss the difference later).
Part 2 - The Basics
Before you can position your site to do well in the search engines, you need to understand search engine fundamentals.
A search engine is a giant database that lists sites on the Internet. You access the database when you enter keyword searches and receive a list of relevant sites.
Search sites are the Internet's Yellow Pages.
Think of a search engine as a giant, automated version of the yellow pages. If you need information on "party planning" from the yellow pages, there are several steps to retrieving it.
Go to the yellow pages and look under the alphabetized subject list for "party."
Note the subcategories: "party planning" "party - children's", "party - rental equipment", and so on.
Examine the companies listed under "party - planning" and decide which company best meets your needs.
You can repeat this process online using a search engine.
Search Engines Versus Search Directories.
People use both search engines and directories without ever realizing there is a difference between the two.
Directories (Yahoo, LookSmart) have human editors who review web pages, rank them, and then organize them into categorized lists with brief descriptions. The categories and descriptions are based on submissions, but are edited by professional editors (real people in the loop reviewing the sites being submitted).
Search Engines (AltaVista, Excite, Google) have automated programs called spiders that index sites and score pages based on proprietary guidelines. There is no human judgment involved. Search engines index all the information on all the Web pages they find. The indexes are generated automatically, based on the words and phrases that are found on Web pages.
What is a Search Engine?
Search engines send automated computer programs (called robots or spiders) to crawl the Internet in search of Web pages. Basically these spiders follow links to travel from URL to URL. When they visit your Web site, the robot indexes (or records) the text of your page or pages (if it is a deep crawling spider) and stores it in the search engine's index. Later, when a user enters a search query at the search engine's Web site, the search engine scans Web pages in its index for pages that provide the best match.
In theory, the search engine spider is supposed to be able to find all the sites on the Internet. However, since new sites are being added daily, it's risky to assume that the spider will find you. Expedite the process by submitting your URL to the search engines.
Not knowing the difference between a directory and a search engine can burn you!
What is a Directory?
Unlike the automated search engine process, each entry in a directory is first reviewed by a human being. You submit a short description to the directory for your entire site, or editors write one for sites they review. A keyword search will only look for matches in these descriptions, so be careful how you describe your site. Techniques to receive a high search engine rating will not work with a directory. While good content is necessary for search engines, both good content AND visual appeal are mandatory in human-edited directories. Remember, manual review takes time!
The typical time lag between free submission of a site and its actual listing in Yahoo is five months. You can speed up the process at some directories, but expect to pay for that service. This trend will probably continue.
Yahoo's Business Express Program, offers express guaranteed consideration of your commercial Web site within seven (7) business days.
Looksmart moved to an exclusive pay for listing scheme - all new submissions must pay to have their site reviewed.
Open Directory Project is a free directory. (Hint: If you get your site listed here, it will help you later in Google.)
When you submit to a directory, do it by hand and take your time. You need to impress human reviewers with your site so high-quality content and design are critical to your success.
Search Engine and Directory Hierarchy.
There are literally thousands of search engines on the Internet, but naturally you're most concerned about your ranking on the high-traffic sites. Some of the smaller search engines may not bring you a lot of traffic, but your listing gives you another source of links (which can help in your overall link popularity building).
If you can do well on the sites listed below, you will probably do well on others too.
Top Search Engines
AltaVista
Lycos
Teoma
Overture
Top Search Directories
Yahoo
LookSmart
Open Directory
Zeal
Part 3 - How to get listed
Don't wait to be discovered! Submit your URL directly to the search engine or directory.
Search Engine submissions.
There are two ways to submit to search engines and directories, manually or using an automated submission tool. Here is a summary of both methods.
Manual Submission - Use the Add URL form from the search engine site itself. This way, you have absolute control over where your site is submitted. However, this process is that it is a very time consuming and labor intensive activity. Some search engines bury their Add URL form so far down in the site that one wonders if they are intentionally trying to thwart potential applicants.
Automated Submission Tool - Fill in the data once and the tool automatically submits your URL to multiple engines. It is a fast, easy one step process and you only have to fill in the data forms once.
There are several features you should look for in an automated submission tool.
The number one item of importance is to make sure the submission tool does not submit to directories. If you look down the list of places the tool submits and you see directories listed, leave and do not look back! You can be assured that NetMechanic's Search Engine Starter only submits to search engines.
The second thing to look for in an automated submission tool is to find one that allows you to pick and choose which engines to submit to. If you are doing well in one engine, but not in another, you may want to submit to the search engine where you need improvement and not submit to the engine where you are doing well. Again, NetMechanic's Search Engine Starter provides the user the flexibility to submit any page on their Web site to their choice of 28 different search engines.
Find a submission service that monitors search engine spam. Because most submission services submit to many search engines, you may receive spam email by some of the smaller engines that occasionally sell their email addresses.
Note: It is not the submission tool company that is selling the email addresses, it is the search engines themselves. NetMechanic's Search Engine Starter allows you to use an alternate email address when submitting your site. Additionally, NetMechanic monitors the search engines it submits to and purges spam-abusive engines from the submission list.
Bottom Line:
Submit your site to directories by hand. Save time by using a submission tool to submit to search engines.
How often do I submit?
Your best strategy is to submit weekly until your site gets listed. Check your listing frequently. If your site disappears suddenly, you may be the victim of a search engine database omission. Search engines frequently have multiple versions of their databases and they aren't always in sync. You may be listed in one version of their database and not in another. Your only recourse is to resubmit your site.
To see if you have even been picked up in a search engine, go to the search engine's site and do a search with your company's domain name as the search query.
Directory Submissions.
Submitting to a directory is a much more involved specialized process. Don't do it in a rush and don't use an automated submission tool. The better submission tools, like Search Engine Starter, don't submit to directories.
How long does it take to get listed?
These times vary with search engines and directories. The search engines will optimistically report a very short time, but most sites get listed within the following times:
Google 4 - 6 weeks
Lycos 4 - 6 weeks
WiseNut 6 weeks
The reality is that most search engines and directories are very backlogged and slow to get listings added to their databases. Don't be surprised if you experience waits much longer than these. As mentioned earlier, you may wait over 5 months to see your site get listed on Yahoo!, if it gets listed at all.
We recommend that if your site isn't listed within the time periods above, that you resubmit your site to the search engine where you are not listed.
Is being listed in the search engines good enough?
Unfortunately no.
A listing won't automatically increase your traffic. A good ranking may. You want to be listed on the first three pages of the search engine results page. Most web surfers aren't patient enough to look more than the first 20-40 listed links. In fact there is a considerable drop off just going from the first to the second page.
Part 4 - How to improve your ranking.
How do search engines rank pages?
Search engines use a ranking algorithm to determine the order in which matching web pages are returned on the results page. Each web page is graded on the number of the search terms it contains, where the words are located in the document, and other criteria that changes frequently.
All search engines have a different method of ranking. That's why you might rank number 1 on one engine and number 25 on another. Robots look for relevance and rank results on a secret ever-changing algorithm. Some look at TITLE, some look at META tags, some look for link popularity. Search engine optimization means optimizing the Web site for the best possible positioning based on the page's keywords and description.
NetMechanic's Search Engine Power Pack has a search engine optimization package that will walk you through the whole optimization process. NetMechanic has numerous experts who have conducted extensive tests to help identify what techniques work to better your ranking in the search engines. Additionally, we have identified what can get you into trouble with search engines.
General tips to get a good ranking.
1. Create a good site with good content.
This is critical, especially as search engines grow in sophistication. If your site contains worthwhile material, users will return to your site and will recommend it to others. Other sites will link to you - which will in turn help you by improving your link popularity.
2. Pick keywords visitors will actually use on a search engine query.
If you have keywords that are very competitive, consider narrowing your focus to improve results. The keyword "horse" will return thousands of responses and may not place you near the top, while "Appaloosa" is more focused and targeted to a particular query.
Consider using a keyword phrase instead of just one keyword. Visitors to search engines use phrases to narrow their searches. For example, instead of using a keyword like "horse" that would return too many responses, use a more specific keyword phrase like "Alabama Quarter horse."
Brainstorm a good list of list of keywords. Tap into other people - a fresh perspective can help uncover words you may have missed. This keyword analysis article offers some useful tips on brainstorming.
Don't just guess at which keywords are popular, get quantitative feedback using the Keyword Popularity tool included in Search Engine Power Pack. Remember, if you pick the wrong keywords, all your optimization will be wasted. See story on Keyword Selection.
3. Include keywords in your TITLE tag.
Pages with keywords appearing in the TITLE are assumed to be more relevant to the topic than those without.
4. Use keywords in META Keyword and Description tags.
Using META tags will not hurt you in search engines that don't use them, and they can definitely help you in search engines that do index them. While they are not as important as the TITLE tag, META tags can give you the edge over your competition since most web sites don't even use them.
5. Use your keywords throughout your page.
Search engines will check to see if the keywords appear near the top of a web page, such as in the headline or in the first few paragraphs of text. They assume that any page relevant to the topic will mention those words right from the beginning.
6. Have a good keyword density on your page.
Keyword density is derived by dividing the frequency of that word by the total words on the page. Frequency is a major factor in how search engines determine relevancy. A search engine will analyze how often keywords appear in relation to other words in a web page. Those with a higher frequency are often deemed more relevant than other web pages. This can turn into a balancing act as too high a density can be considered spam by some engines. Usually you are safe if your keyword density falls between 1 - 5 %.
7. Continually work on improving your link popularity.
Listings on popular Web sites can increase your traffic significantly. They do this in two ways:
They give potential visitors multiple paths to your Web site.
They can increase your ranking in search engines that use link popularity as part of their formula.
Most search engines use link popularity as relevance criteria. For example, the Google search engine (not their new directory) is based almost entirely on link popularity.
Summary
Success with search engines and directories is not one magical thing you do specifically. It is the culmination of your whole strategy. It is a time consuming, labor intensive activity with great rewards.
Bottom Line:
Use Search Engine Power Pack at least once a month to help you get more traffic from the search engines.
NetMechanic's Search Engine Power Pack is a search engine optimization power house. It's a five tool bundle that can help you improve your search engine ranking and bring more traffic to your site. Power Pack walks you through the whole search engine optimization process. From selecting your most effective keywords and building META tags, to optimizing your pages for peak search engine performance, to submitting your pages to the search engines of your choice and to tracking your site's performance in the search engines over time. NetMechanic has the one stop solution that will greatly improve your search engine performance.
CSS Tip
by Kumar anubhav,
Senior Web Analyst,
NetMechanic, Inc.
|
In our June 2003 Beginner Tip, we discussed the benefits of removing deprecated HTML tags from your Web pages. Now we're going to take an existing Web page and show you how to do just that. In 5 easy steps we'll analyze the page, create CSS definitions, delete the HTML formatting tags, add CSS-specific formatting to enhance the page, and validate the code.
The Goal: Quick And Easy Pages
First, look at this example page that uses all HTML formatting and images for navigation.
The total size of this page is rather large for such a simple layout:
| HTML code: | 6k | |
| 5 navigation buttons: | 15k (3k each) | |
| Logo image: | 12k | |
| Total: | 33k | |
It's such a simple layout to have such a large overall download size, isn't it? And the code is so cluttered with formatting tags that it's hard to find individual page elements. Don't worry: we can fix both problems with CSS.
Step One: Find Common Elements
Next, we'll scan the page's source code to see if the formatting of any page elements could be grouped together using CSS rules. We find five!
| Page Element | Common Formatting | Style Rule |
|---|---|---|
| body | font name
font size font color background color | font-family:verdana;
font-size:12px; color:navy; background-color:maroon; |
| table | background color
font name font size font color | background-color:white;
font-family:verdana; font-size:12px; color:navy; |
| Section headers | font-size | Replace with tags |
| Data table | background color | background-color:navy; |
| headers | font color
centered text bold text | font-color:yellow;
text-align:center; font-weight:bold; |
| Data table cells | centered text
bold text | text-align:center;
font-weight:bold; |
Step Two: Create The Style Definitions
Always save a copy of the original file before you make major changes to any important page in your Web site. Here, we take the example file titled "DeprecatedTags.htm" and save it to a new file titled "CSS_Formatting.htm."
Refer to the chart in step one. Most of the style definitions are ready to place into the new page's HEAD section like this:
|
Note that we specifically added the table tags to the style rule for the document's body. It shouldn't be necessary because tables should inherit the BODY definition because they're part of the document's body - but Netscape browsers don't see it that way. Avoid this Netscape bugby specifically adding table elements to your body style definition.
Also note that we created two class definitions: tableHeading and cost. We'll use these inside the TD tags in the data tables.
Step 3: Remove HTML Formatting Tags
On this page, removing the formatting tags is relatively easy because the major problems are opening and closing FONT tags and the CENTER attribute.
Be careful! This third step is one of the most time-consuming and frustrating steps. Each time you add or delete code, you risk making a coding error. Some can be catastrophic and hard to find because they may only cause problems in a particular browser.
Learn more about browser incompatibility problems in our browser compatibility tutorial.
|
Then finally, replace the paragraph tags with the section headers with structural H2 tags:
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Finally, apply the CSS class definitions we created in Step 2. Apply the tableHeader class to the data tables' header cells and data cells:
Check out the revised example file. It's a lot easier to locate specific page elements. Its size is down to 5k for the HTML code. If we were to place the CSS definitions inside an external file, we could save another 1k of download and reuse the styles on each page in the site.
But for now, let's leave the styles in the HEAD section because there are a few changes we can make to enhance the page's visual appeal and decrease the total download size even more.
Step 4: Add CSS-specific Formatting
Look at the navigation menu. It's created using 5 separate image files. They look ok, but is there really a reason to use images? We could easily style some nice navigation buttons using CSS.
This technique is covered extensively in our Create Stylish MenusWebmaster tip, so we won't duplicate it in this story. We save 15k of download by replacing those images with text navigation. We alsomake the page more accessible to search engine spiders and visitors with disabilities!
The page has three distinct sections, so maybe it would be nice to visually separate them with some borders. With CSS, we can add a border to just one side of a page element.
Let's create two more classes and add them to the style definition in the HEAD section:
|
.bottomBorder {border-bottom: 3px solid navy;} .leftBorder {border-left: 3px solid navy;} |
Then, apply them inside the appropriate TD tags where you want the border to display.
This third example page shows the results of the changes we made here in Step 4. Look at the source code and compare it to the original file.
Of course, the STYLE section of the page takes up a bit of space. Now that we have the page like we want it, we could place all style definitions in an external CSS file.
That change would decrease the total download for the CSS Web page:
| HTML code: | 4k | |
| 5 navigation buttons: | 0k | |
| Logo image: | 12k | |
| External style sheet: | 1k | |
| Total: | 17k | |
With a little time, effort, and CSS, we've created a page with the same information and functionality as the original page - except that it's approximately 50% smaller! You'll see an even greater savings on pages that are more text-heavy, but we tried to keep the example simple so you can understand the concepts before you begin experimenting with your own pages.
Step 5: Validate The New HTML Code!
This last step is the one webmasters most often overlook: validate your code! We've made a lot of changes and deleted a lot of tags. That's great because now you have a page that's a lot easier to maintain.
But chances are, you'll have made some errors along the way. The most common error is a lot of orphan closing FONT tags scattered throughout your code. Also, look carefully for opening and closing carats (<>) or quotation marks that you may have accidentally deleted.
Any of those simple errors can confuse browsers and search engine spiders and make it hard for them to separate the page's code from the content that should display on the page.
The process can be tedious, but it's critical! One quick and easy solution is to use HTML Toolbox to validate your code. It alerts you to HTML code errors that can break your page and the subscription version will even prepare a corrected version of your page that you can upload to your own server.
Even better, HTML Toolbox's Load Time Check feature will show you how quickly your pages download at different modem speeds. You won't have to guess whether or not your revised pages download faster, you'll know - and so will your visitors!
WiMAX
WiMAX
WiMAX (Worldwide Interoperability for Microwave Access) is a telecommunications protocol that provides fixed and fully mobile internet access. The current WiMAX revision provides up to 40 Mbit/s[1][2] with the IEEE 802.16m update expected offer up to 1 Gbit/s fixed speeds. The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX[3] as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL".[4]
WiMAX base station equipment with a sector antenna and wireless modem on top
A pre-WiMAX CPE of a 26 km (16 mi) connection mounted 13 metres (43 ft) above the ground (2004, Lithuania).
Contents
• 1 Terminology
• 2 Uses
o 2.1 Broadband
o 2.2 Backhaul
o 2.3 Triple-play
o 2.4 Rapid deployment
• 3 Connecting to WiMAX
o 3.1 WiMAX Gateways
o 3.2 WiMAX Dongles
o 3.3 WiMAX Mobiles
• 4 Technical information
o 4.1 WiMAX and the IEEE 802.16 Standard
o 4.2 Physical layer
o 4.3 MAC (data link) layer
o 4.4 Deployment
o 4.5 Integration with an IP-based network
o 4.6 Spectrum allocation
o 4.7 Spectral efficiency
o 4.8 Inherent Limitations
o 4.9 Silicon implementations
o 4.10 Comparison with Wi-Fi
• 5 Conformance testing
• 6 Associations
o 6.1 WiMAX Forum
o 6.2 WiMAX Spectrum Owners Alliance
• 7 Competing technologies
o 7.1 Harmonization
o 7.2 Comparison
• 8 Future development
• 9 Interference
• 10 Deployments
• 11 See also
• 12 References
• 13 External links
Terminology
WiMAX refers to interoperable implementations of the IEEE 802.16 wireless-networks standard (ratified by the WiMAX Forum), in similarity with Wi-Fi, which refers to interoperable impleme]] Wireless LAN standard (ratified by the Wi-Fi Alliance). The WiMAX Forum certification allows vendors to sell their equipment as WiMAX (Fixed or Mobile) certified, thus ensuring a level of interoperability with other certified products, as long as they fit the same profile.
The IEEE 802.16 standard forms the basis of 'WiMAX' and is sometimes referred to colloquially as "WiMAX", "Fixed WiMAX", "Mobile WiMAX", "802.16d" and "802.16e."[5] Clarification of the formal names are as follow:
• 802.16-2004 is also known as 802.16d, which refers to the working party that has developed that standard. It is sometimes referred to as "Fixed WiMAX," since it has no support for mobility.
• 802.16e-2005, often abbreviated to 802.16e, is an amendment to 802.16-2004. It introduced support for mobility, among other things and is therefore also known as "Mobile WiMAX".
Mobile WiMAX is the WiMAX incarnation that has the most commercial interest to date and is being actively deployed in many countries. Mobile WiMAX is also the basis of future revisions of WiMAX. As such, references to and comparisons with "WiMAX" in this Wikipedia article mean "Mobile WiMAX".
Uses
The bandwidth and range of WiMAX make it suitable for the following potential applications:
• Providing portable mobile broadband connectivity across cities and countries through a variety of devices.
• Providing a wireless alternative to cable and DSL for "last mile" broadband access.
• Providing data, telecommunications (VoIP) and IPTV services (triple play).
• Providing a source of Internet connectivity as part of a business continuity plan.
Broadband
Companies are deploying WiMAX to provide mobile broadband or at-home broadband connectivity across whole cities or countries. In many cases this has resulted in competition in markets which typically only had access to broadband through an existing incumbent DSL (or similar) operator.
Additionally, given the relatively low cost to deploy a WiMAX network (in comparison to GSM, DSL or Fiber-Optic), it is now possible to provide broadband in places where it may have not been economically viable.
Backhaul
WiMAX is a possible replacement candidate for cellular phone technologies such as GSM and CDMA, or can be used as an overlay to increase capacity. Fixed WiMAX is also considered as a wireless backhaul technology for 2G, 3G, and 4G networks in both developed and developing nations.[6][7]
In North America, backhaul for urban cellular operations is typically provided via one or more copper wire line T1 connections, whereas remote cellular operations are sometimes backhauled via satellite. In most other regions, urban and rural backhaul is usually provided by microwave links. (The exception to this is where the network is operated by an incumbent with ready access to the copper network, in which case T1 lines may be used.) WiMAX is a broadband platform and as such has much more substantial backhaul bandwidth requirements than legacy cellular applications. Therefore, traditional copper wire line backhaul solutions are not appropriate. Consequently the use of wireless microwave backhaul is on the rise in North America and existing microwave backhaul links in all regions are being upgraded.[8] Capacities of between 34 Mbit/s and 1 Gbit/s[citation needed] are routinely being deployed with latencies in the order of 1 ms. In many cases, operators are aggregating sites using wireless technology and then presenting traffic on to fiber networks where convenient.
Triple-play
WiMAX supports the technologies that make triple-play service offerings possible (such as Quality of Service and Multicasting).
As a result, it is possible for a WiMAX operator to not only provide high-speed broadband internet access, but also VoIP and IPTV services to customers with relative ease. This enables a WiMAX service to be a replacement for DSL, Cable and Telephony services.
On May 7, 2008 in the United States, Sprint Nextel, Google, Intel, Comcast, Bright House, and Time Warner announced a pooling of an average of 120 MHz of spectrum and merged with Clearwire to form a company which will take the name Clear. The new company hopes to benefit from combined services offerings and network resources as a springboard past its competitors. The cable companies will provide media services to other partners while gaining access to the wireless network as a Mobile virtual network operator to provide triple-play services.
Some analysts have questioned how the deal will work out: Although fixed-mobile convergence has been a recognized factor in the industry, prior attempts to form partnerships among wireless and cable companies have generally failed to lead to significant benefits to the participants. Other analysts point out that as wireless progresses to higher bandwidth, it inevitably competes more directly with cable and DSL, inspiring competitors into collaboration. Also, as wireless broadband networks grow denser and usage habits shift, the need for increased backhaul and media service will accelerate, therefore the opportunity to leverage cable assets is expected to increase.
Rapid deployment
• WiMAX access was used to assist with communications[citation needed] in Aceh, Indonesia, after the tsunami in December 2004. All communication infrastructure in the area, other than amateur radio, was destroyed[citation needed], making the survivors unable to communicate with people outside the disaster area and vice versa. WiMAX provided broadband access that helped regenerate communication to and from Aceh.[citation needed]
• WiMAX hardware was donated by Intel Corporation to assist the Federal Communications Commission (FCC) and FEMA in their communications efforts in the areas affected by Hurricane Katrina.[9] In practice, volunteers used mainly self-healing mesh, Voice over Internet Protocol (VoIP), and a satellite uplink combined with Wi-Fi on the local link.[10]
Connecting to WiMAX
A WiMAX Gateway which provides VoIP, Ethernet and WiFi connectivity
A WiMAX USB modem for mobile internet
There are numerous devices on the market that provide connectivity to a WiMAX network. These are known as the "subscriber unit" (SU).
There is an increasing focus on portable units. This includes handsets (similar to cellular smartphones); PC peripherals (PC Cards or USB dongles); and embedded devices in laptops, which are now available for Wi-Fi services. In addition, there is much emphasis by operators on consumer electronics devices such as Gaming consoles, MP3 players and similar devices. It is notable that WiMAX is more similar to Wi-Fi than to 3G cellular technologies.
The WiMAX Forum website provides a list of certified devices. However, this is not a complete list of devices available as certified modules are embedded into laptops, MIDs (Mobile internet devices), and other private labeled devices.
WiMAX Gateways
WiMAX gateway devices are available as both indoor and outdoor versions from several manufacturers. Many of the WiMAX gateways that are offered by manufactures such as ZyXEL, Motorola, and Greenpacket are stand-alone self-install indoor units. Such devices typically sit near the customer's window with the best WiMAX signal, and provide:
• An integrated Wi-Fi access point to provide the WiMAX Internet connectivity to multiple devices throughout the home or business.
• Ethernet ports should you wish to connect directly to your computer or DVR instead.
• One or two PSTN telephone jacks to connect your land-line phone and take advantage of VoIP.
Indoor gateways are convenient, but radio losses mean that the subscriber may need to be significantly closer to the WiMAX base station than with professionally-installed external units.
Outdoor units are roughly the size of a laptop PC, and their installation is comparable to the installation of a residential satellite dish. A higher-gain directional outdoor unit will generally result in greatly increased range and throughput but with the obvious loss of practical mobility of the unit.
WiMAX Dongles
There are a variety of USB dongles on the market which provide connectivity to a WiMAX network. Generally these devices are connected to a notebook or netbook whilst on the go. Dongles typically have omnidirectional antennae which are of lower-gain compared to other devices, as such these devices are best used in areas of good coverage.
WiMAX Mobiles
HTC announced the first WiMAX enabled mobile phone, the Max 4G, on Nov 12th 2008.[11] The device was only available to certain markets in Russia on the Yota network.
HTC released the second WiMAX enabled mobile phone, the EVO 4G, March 23, 2010 at the CTIA conference in Las Vegas. The device made available on June 4, 2010[12] is capable of both EV-DO(3G) and WiMAX(4G) as well as simultaneous data & voice sessions. The device also has a front-facing camera enabling the use of video conversations.[13] A number of WiMAX Mobiles are expected to hit the US market in 2010.[14]
Technical information
Illustration of a WiMAX MIMO board
WiMAX and the IEEE 802.16 Standard
The current WiMAX revision is based upon IEEE Std 802.16e-2005,[15] approved in December 2005. It is a supplement to the IEEE Std 802.16-2004,[16] and so the actual standard is 802.16-2004 as amended by 802.16e-2005. Thus, these specifications need to be considered together.
IEEE 802.16e-2005 improves upon IEEE 802.16-2004 by:
• Adding support for mobility (soft and hard handover between base stations). This is seen as one of the most important aspects of 802.16e-2005, and is the very basis of Mobile WiMAX.
• Scaling of the Fast Fourier transform (FFT) to the channel bandwidth in order to keep the carrier spacing constant across different channel bandwidths (typically 1.25 MHz, 5 MHz, 10 MHz or 20 MHz). Constant carrier spacing results in a higher spectrum efficiency in wide channels, and a cost reduction in narrow channels. Also known as Scalable OFDMA (SOFDMA). Other bands not multiples of 1.25 MHz are defined in the standard, but because the allowed FFT subcarrier numbers are only 128, 512, 1024 and 2048, other frequency bands will not have exactly the same carrier spacing, which might not be optimal for implementations.
• Advanced antenna diversity schemes, and hybrid automatic repeat-request (HARQ)
• Adaptive Antenna Systems (AAS) and MIMO technology
• Denser sub-channelization, thereby improving indoor penetration
• Introducing Turbo Coding and Low-Density Parity Check (LDPC)
• Introducing downlink sub-channelization, allowing administrators to trade coverage for capacity or vice versa
• Fast Fourier transform algorithm
• Adding an extra QoS class for VoIP applications.
SOFDMA (used in 802.16e-2005) and OFDM256 (802.16d) are not compatible thus equipment will have to be replaced if an operator is to move to the later standard (e.g., Fixed WiMAX to Mobile WiMAX).
Physical layer
The original version of the standard on which WiMAX is based (IEEE 802.16) specified a physical layer operating in the 10 to 66 GHz range. 802.16a, updated in 2004 to 802.16-2004, added specifications for the 2 to 11 GHz range. 802.16-2004 was updated by 802.16e-2005 in 2005 and uses scalable orthogonal frequency-division multiple access (SOFDMA) as opposed to the fixed orthogonal frequency-division multiplexing (OFDM) version with 256 sub-carriers (of which 200 are used) in 802.16d. More advanced versions, including 802.16e, also bring multiple antenna support through MIMO (See WiMAX MIMO). This brings potential benefits in terms of coverage, self installation, power consumption, frequency re-use and bandwidth efficiency.
MAC (data link) layer
The WiMAX MAC uses a scheduling algorithm for which the subscriber station needs to compete only once for initial entry into the network. After network entry is allowed, the subscriber station is allocated an access slot by the base station. The time slot can enlarge and contract, but remains assigned to the subscriber station, which means that other subscribers cannot use it. In addition to being stable under overload and over-subscription, the scheduling algorithm can also be more bandwidth efficient. The scheduling algorithm also allows the base station to control Quality of service (QoS) parameters by balancing the time-slot assignments among the application needs of the subscriber stations.
Deployment
As a standard intended to satisfy needs of next-generation data networks (4G), WiMAX is distinguished by its dynamic burst algorithm modulation adaptive to the physical environment the RF signal travels through. Modulation is chosen to be more spectrally efficient (more bits per OFDM/SOFDMA symbol). That is, when the bursts have a high signal strength and a high carrier to noise plus interference ratio (CINR), they can be more easily decoded using digital signal processing (DSP). In contrast, operating in less favorable environments for RF communication, the system automatically steps down to a more robust mode (burst profile) which means fewer bits per OFDM/SOFDMA symbol; with the advantage that power per bit is higher and therefore simpler accurate signal processing can be performed.
Burst profiles are used inverse (algorithmically dynamic) to low signal attenuation; meaning throughput between clients and the base station is determined largely by distance. Maximum distance is achieved by the use of the most robust burst setting; that is, the profile with the largest MAC frame allocation trade-off requiring more symbols (a larger portion of the MAC frame) to be allocated in transmitting a given amount of data than if the client were closer to the base station.
The client's MAC frame and their individual burst profiles are defined as well as the specific time allocation. However, even if this is done automatically then the practical deployment should avoid high interference and multipath environments. The reason for which is obviously that too much interference causes the network function poorly and can also misrepresent the capability of the network.
The system is complex to deploy as it is necessary to track not only the signal strength and CINR (as in systems like GSM) but also how the available frequencies will be dynamically assigned (resulting in dynamic changes to the available bandwidth.) This could lead to cluttered frequencies with slow response times or lost frames.
As a result the system has to be initially designed in consensus with the base station product team to accurately project frequency use, interference, and general product functionality.
Integration with an IP-based network
The WiMAX Forum WiMAX Architecture
The WiMAX Forum has proposed an architecture that defines how a WiMAX network can be connected with an IP based core network, which is typically chosen by operators that serve as Internet Service Providers (ISP); Nevertheless the WiMAX BS provide seamless integration capabilities with other types of architectures as with packet switched Mobile Networks.
The WiMAX forum proposal defines a number of components, plus some of the interconnections (or reference points) between these, labeled R1 to R5 and R8:
• SS/MS: the Subscriber Station/Mobile Station
• ASN: the Access Service Network[17]
• BS: Base station, part of the ASN
• ASN-GW: the ASN Gateway, part of the ASN
• CSN: the Connectivity Service Network
• HA: Home Agent, part of the CSN
• AAA: Authentication, Authorization and Accounting Server, part of the CSN
• NAP: a Network Access Provider
• NSP: a Network Service Provider
It is important to note that the functional architecture can be designed into various hardware configurations rather than fixed configurations. For example, the architecture is flexible enough to allow remote/mobile stations of varying scale and functionality and Base Stations of varying size - e.g. femto, pico, and mini BS as well as macros.
Spectrum allocation
There is no uniform global licensed spectrum for WiMAX, however the WiMAX Forum has published three licensed spectrum profiles: 2.3 GHz, 2.5 GHz and 3.5 GHz, in an effort to drive standardisation and decrease cost.
In the USA, the biggest segment available is around 2.5 GHz,[18] and is already assigned, primarily to Sprint Nextel and Clearwire. Elsewhere in the world, the most-likely bands used will be the Forum approved ones, with 2.3 GHz probably being most important in Asia. Some countries in Asia like India and Indonesia will use a mix of 2.5 GHz, 3.3 GHz and other frequencies. Pakistan's Wateen Telecom uses 3.5 GHz.
Analog TV bands (700 MHz) may become available for WiMAX usage, but await the complete roll out of digital TV, and there will be other uses suggested for that spectrum. In the USA the FCC auction for this spectrum began in January 2008 and, as a result, the biggest share of the spectrum went to Verizon Wireless and the next biggest to AT&T.[19] Both of these companies have stated their intention of supporting LTE, a technology which competes directly with WiMAX. EU commissioner Viviane Reding has suggested re-allocation of 500–800 MHz spectrum for wireless communication, including WiMAX.[20]
WiMAX profiles define channel size, TDD/FDD and other necessary attributes in order to have inter-operating products. The current fixed profiles are defined for both TDD and FDD profiles. At this point, all of the mobile profiles are TDD only. The fixed profiles have channel sizes of 3.5 MHz, 5 MHz, 7 MHz and 10 MHz. The mobile profiles are 5 MHz, 8.75 MHz and 10 MHz. (Note: the 802.16 standard allows a far wider variety of channels, but only the above subsets are supported as WiMAX profiles.)
Since October 2007, the Radio communication Sector of the International Telecommunication Union (ITU-R) has decided to include WiMAX technology in the IMT-2000 set of standards.[21] This enables spectrum owners (specifically in the 2.5-2.69 GHz band at this stage) to use WiMAX equipment in any country that recognizes the IMT-2000.
Spectral efficiency
One of the significant advantages of advanced wireless systems such as WiMAX is spectral efficiency. For example, 802.16-2004 (fixed) has a spectral efficiency of 3.7 (bit/s)/Hertz, and other 3.5–4G wireless systems offer spectral efficiencies that are similar to within a few tenths of a percent. The notable advantage of WiMAX comes from combining SOFDMA with smart antenna technologies. This multiplies the effective spectral efficiency through multiple reuse and smart network deployment topologies. The direct use of frequency domain organization simplifies designs using MIMO-AAS compared to CDMA/WCDMA methods, resulting in more effective systems.
Inherent Limitations
A commonly-held misconception is that WiMAX will deliver 70 Mbit/s over 50 kilometers. Like all wireless technologies, WiMAX can either operate at higher bitrates or over longer distances but not both: operating at the maximum range of 50 km (31 miles) increases bit error rate and thus results in a much lower bitrate. Conversely, reducing the range (to under 1 km) allows a device to operate at higher bitrates.
A recent city-wide deployment of WiMAX in Perth, Australia, has demonstrated that customers at the cell-edge with an indoor CPE typically obtain speeds of around 1–4 Mbit/s, with users closer to the cell tower obtaining speeds of up to 30 Mbit/s.[citation needed]
Like all wireless systems, available bandwidth is shared between users in a given radio sector, so performance could deteriorate in the case of many active users in a single sector. However, with adequate capacity planning and the use of WiMAX's Quality of Service, a minimum guaranteed throughput for each subscriber can be put in place. In practice, most users will have a range of 4-8 Mbit/s services and additional radio cards will be added to the base station to increase the number of users that may be served as required.
Silicon implementations
A critical requirement for the success of a new technology is the availability of low-cost chipsets and silicon implementations.
WiMAX has a strong silicon ecosystem with a number of specialized companies producing baseband ICs and integrated RFICs for implementing full-featured WiMAX Subscriber Stations in the 2.3, 2.5 and 3.5Ghz band (refer to 'Spectrum allocation' above). It is notable that most of the major semiconductor companies have not developed WiMAX chipsets of their own and have instead chosen to invest in and/or utilise the well developed products from smaller specialists or start-up suppliers. These companies include but not limited to Beceem, Sequans and PicoChip. The chipsets from these companies are used in the majority of WiMAX devices.
Intel Corporation is a leader in promoting WiMAX, but has limited its WiMAX chipset development and instead chosen to invest in these specialized companies producing silicon compatible with the various WiMAX deployments throughout the globe.
Comparison with Wi-Fi
Comparisons and confusion between WiMAX and Wi-Fi are frequent because both are related to wireless connectivity and Internet access.
• WiMAX is a long range system, covering many kilometres, that uses licensed or unlicensed spectrum to deliver connection to a network, in most cases the Internet.
• Wi-Fi uses unlicensed spectrum to provide access to a local network.
• Wi-Fi is more popular in end user devices.
• Wi-Fi runs on the Media Access Control's CSMA/CA protocol, which is connectionless and contention based, whereas WiMAX runs a connection-oriented MAC.
• WiMAX and Wi-Fi have quite different quality of service (QoS) mechanisms:
o WiMAX uses a QoS mechanism based on connections between the base station and the user device. Each connection is based on specific scheduling algorithms.
o Wi-Fi uses contention access - all subscriber stations that wish to pass data through a wireless access point (AP) are competing for the AP's attention on a random interrupt basis. This can cause subscriber stations distant from the AP to be repeatedly interrupted by closer stations, greatly reducing their throughput.
• Both 802.11 and 802.16 define Peer-to-Peer (P2P) and ad hoc networks, where an end user communicates to users or servers on another Local Area Network (LAN) using its access point or base station. However, 802.11 supports also direct ad hoc or peer to peer networking between end user devices without an access point while 802.16 end user devices must be in range of the base station.
Wi-Fi and WiMAX are complementary. WiMAX network operators typically provide a WiMAX Subscriber Unit which connects to the metropolitan WiMAX network and provides Wi-Fi within the home or business for local devices (e.g., Laptops, Wi-Fi Handsets, smartphones) for connectivity. This enables the user to place the WiMAX Subscriber Unit in the best reception area (such as a window), and still be able to use the WiMAX network from any place within their residence.
Conformance testing
TTCN-3 test specification language is used for the purposes of specifying conformance tests for WiMAX implementations. The WiMAX test suite is being developed by a Specialist Task Force at ETSI (STF 252).[22]
Associations
WiMAX Forum
The WiMAX Forum is a non profit organization formed to promote the adoption of WiMAX compatible products and services.[23]
A major role for the organization is to certify the interoperability of WiMAX products.[24] Those that pass conformance and interoperability testing achieve the "WiMAX Forum Certified" designation, and can display this mark on their products and marketing materials. Some vendors claim that their equipment is "WiMAX-ready", "WiMAX-compliant", or "pre-WiMAX", if they are not officially WiMAX Forum Certified.
Another role of the WiMAX Forum is to promote the spread of knowledge about WiMAX. In order to do so, it has a certified training program that is currently offered in English and French. It also offers a series of member events and endorses some industry events.
WiSOA was the first global organization composed exclusively of owners of WiMAX spectrum with plans to deploy WiMAX technology in those bands. WiSOA focussed on the regulation, commercialisation, and deployment of WiMAX spectrum in the 2.3–2.5 GHz and the 3.4–3.5 GHz ranges. WiSOA merged with the Wireless Broadband Alliance in April 2008. [25]
Competing technologies
Speed vs. Mobility of wireless systems: Wi-Fi, HSPA, UMTS, GSM
Within the marketplace, WiMAX's main competition comes from existing, widely deployed wireless systems such as UMTS, CDMA2000, existing Wi-Fi and mesh networking.
In the future, competition will be from the evolution of the major cellular standards to so-called 4G, high-bandwidth, low-latency, all-IP networks with voice services built on top. The worldwide move to 4G for GSM/UMTS and AMPS/TIA (including CDMA2000) is the 3GPP Long Term Evolution effort. However, it has been noted that the likely performance difference between WiMAX as it stands today and LTE when it is eventually commercially available in 2–3 years time, will be negligible.[citation needed]
LTE is expected to be ratified at the end of 2010, with commercial implementations becoming viable within the next two years.. End of 2009 TeliaSonera started commercial deployment in Oslo and Stockholm, In Denmark the 3 big telecoms are upgrading their network, and will make LTE available during 2010.
In some areas of the world, the wide availability of UMTS and a general desire for standardization has meant spectrum has not been allocated for WiMAX: in July 2005, the EU-wide frequency allocation for WiMAX was blocked.
Harmonization
Early WirelessMAN standards, the European standard HiperMAN and Korean standard WiBro have been harmonized as part of WiMAX and are no longer seen as competition but as complementary. All networks now being deployed in South Korea, the home of the WiBro standard, are now WiMAX.
Comparison
Main article: Comparison of wireless data standards
The neutrality of this article is disputed. Please see the discussion on the talk page. Please do not remove this message until the dispute is resolved. (January 2009)
The following table should be treated with caution because it only shows peak rates which are potentially very misleading. In addition, the comparisons listed are not normalized by physical channel size (i.e., spectrum used to achieve the listed peak rates); this obfuscates spectral efficiency and net through-put capabilities of the different wireless technologies listed below.
Comparison of Mobile Internet Access methods Standard
Family Primary Use Radio Tech Downlink (Mbit/s) Uplink (Mbit/s) Notes LTE UMTS/4GSM General 4G OFDMA/MIMO/SC-FDMA 360 80 LTE-Advanced update expected to offer peak rates of at least 1 Gbit/s fixed speeds and 100 Mbit/s to mobile users. WiMAX 802.16e Mobile Internet MIMO-SOFDMA 144 35 WiMAX update IEEE 802.16m expected offer up to 1 Gbit/s fixed speeds. Flash-OFDM Flash-OFDM Mobile Internet
mobility up to 200mph (350km/h) Flash-OFDM 5.3
10.6
15.9 1.8
3.6
5.4 Mobile range 18miles (30km)
extended range 34 miles (55km) HIPERMAN HIPERMAN Mobile Internet OFDM 56.9 56.9 Wi-Fi 802.11
(11n) Mobile Internet OFDM/MIMO 288.9
(Supports 600Mbps @ 40MHz channel width)
iBurst 802.20 Mobile Internet HC-SDMA/TDD/MIMO 95 36 Cell Radius: 3–12 km
Speed: 250kmph
Spectral Efficiency: 13 bits/s/Hz/cell
Spectrum Reuse Factor: "1" EDGE Evolution GSM Mobile Internet TDMA/FDD 1.9 0.9 3GPP Release 7 UMTS W-CDMA
HSDPA+HSUPA
HSPA+ UMTS/3GSM General 3G CDMA/FDD
CDMA/FDD/MIMO 0.384
14.4
56 0.384
5.76
22 HSDPA widely deployed. Typical downlink rates today 2 Mbit/s, ~200 kbit/s uplink; HSPA+ downlink up to 56 Mbit/s. UMTS-TDD UMTS/3GSM Mobile Internet CDMA/TDD 16 16 Reported speeds according to IPWireless using 16QAM modulation similar to HSDPA+HSUPA 1xRTT CDMA2000 Mobile phone CDMA 0.144 0.144 Succeeded by EV-DO EV-DO 1x Rev. 0
EV-DO 1x Rev.A
EV-DO Rev.B CDMA2000 Mobile Internet CDMA/FDD 2.45
3.1
4.9xN 0.15
1.8
1.8xN Rev B note: N is the number of 1.25 MHz chunks of spectrum used.
Future development
The IEEE 802.16m [1] standard is the core technology for the proposed WiMAX Release 2, which enables more efficient, faster, and more converged data communications. The IEEE 802.16m standard has been submitted to the ITU for IMT-Advanced standardization[26]. IEEE 802.16m is one of the major candidates for IMT-Advanced technologies by ITU. Among many enhancements, IEEE 802.16m systems can provide four times faster[clarification needed] data speed than the current WiMAX Release 1 based on IEEE 802.16e technology.
WiMAX Release 2 will provide strong backward compatibility with Release 1 solutions. It will allow current WiMAX operators to migrate their Release 1 solutions to Release 2 by upgrading channel cards or software of their systems. Also, the subscribers who use currently available WiMAX devices can communicate with new WiMAX Release 2 systems without difficulty.
It is anticipated that in a practical deployment, using 4X2 MIMO in the urban microcell scenario with only a single 20-MHz TDD channel available system wide, the 802.16m system can support both 120 Mbit/s downlink and 60 Mbit/s uplink per site simultaneously. It is expected that the WiMAX Release 2 will be available commercially in the 2011-2012 timeframe.[27]
Interference
A field test conducted by SUIRG (Satellite Users Interference Reduction Group) with support from the U.S. Navy, the Global VSAT Forum, and several member organizations yielded results showing interference at 12 km when using the same channels for both the WiMAX systems and satellites in C-band.[28] The WiMAX Forum has yet to respond.
Deployments
Main article: List of deployed WiMAX networks
As example, Korea launched Wimax at 2nd quarter of 2006 and then launched HSPA one quarter after launched Wimax. At the end of 2008 there were 8.4 million HSPA subscribers and 350,000 Wimax subscribers in Korea. Almost all of HSPA subscribers come from 2G and 3G users who have been tempted to upgrade to new devices by high subsidies, whereas Wimax subscribers almost all are newcomers. Deployment of Wimax is still limited (spotted), whereas there are well over 100 countries where HSPA networks are deployed, and even where there is no HSPA coverage there is backward compatibility (using HSPA devices) to pre-existing networks (GSM and WCDMA) with a roaming infrastructure already in place. In the mean time, the HSPA juggernaut looks unstoppable.[29]
As of April 2010, the WiMAX Forum claims there are over 558 WiMAX (fixed and mobile) networks deployed in over 147 countries.[30]
Yota is the largest WiMAX network operator in the world[31] but has announced that it will move new network deployments to LTE and, subsequently, change its existing networks as well.[32]
Internet access
WiMAX (Worldwide Interoperability for Microwave Access) is a telecommunications protocol that provides fixed and fully mobile internet access. The current WiMAX revision provides up to 40 Mbit/s[1][2] with the IEEE 802.16m update expected offer up to 1 Gbit/s fixed speeds. The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX[3] as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL".[4]
WiMAX base station equipment with a sector antenna and wireless modem on top
A pre-WiMAX CPE of a 26 km (16 mi) connection mounted 13 metres (43 ft) above the ground (2004, Lithuania).
Contents
• 1 Terminology
• 2 Uses
o 2.1 Broadband
o 2.2 Backhaul
o 2.3 Triple-play
o 2.4 Rapid deployment
• 3 Connecting to WiMAX
o 3.1 WiMAX Gateways
o 3.2 WiMAX Dongles
o 3.3 WiMAX Mobiles
• 4 Technical information
o 4.1 WiMAX and the IEEE 802.16 Standard
o 4.2 Physical layer
o 4.3 MAC (data link) layer
o 4.4 Deployment
o 4.5 Integration with an IP-based network
o 4.6 Spectrum allocation
o 4.7 Spectral efficiency
o 4.8 Inherent Limitations
o 4.9 Silicon implementations
o 4.10 Comparison with Wi-Fi
• 5 Conformance testing
• 6 Associations
o 6.1 WiMAX Forum
o 6.2 WiMAX Spectrum Owners Alliance
• 7 Competing technologies
o 7.1 Harmonization
o 7.2 Comparison
• 8 Future development
• 9 Interference
• 10 Deployments
• 11 See also
• 12 References
• 13 External links
Terminology
WiMAX refers to interoperable implementations of the IEEE 802.16 wireless-networks standard (ratified by the WiMAX Forum), in similarity with Wi-Fi, which refers to interoperable impleme]] Wireless LAN standard (ratified by the Wi-Fi Alliance). The WiMAX Forum certification allows vendors to sell their equipment as WiMAX (Fixed or Mobile) certified, thus ensuring a level of interoperability with other certified products, as long as they fit the same profile.
The IEEE 802.16 standard forms the basis of 'WiMAX' and is sometimes referred to colloquially as "WiMAX", "Fixed WiMAX", "Mobile WiMAX", "802.16d" and "802.16e."[5] Clarification of the formal names are as follow:
• 802.16-2004 is also known as 802.16d, which refers to the working party that has developed that standard. It is sometimes referred to as "Fixed WiMAX," since it has no support for mobility.
• 802.16e-2005, often abbreviated to 802.16e, is an amendment to 802.16-2004. It introduced support for mobility, among other things and is therefore also known as "Mobile WiMAX".
Mobile WiMAX is the WiMAX incarnation that has the most commercial interest to date and is being actively deployed in many countries. Mobile WiMAX is also the basis of future revisions of WiMAX. As such, references to and comparisons with "WiMAX" in this Wikipedia article mean "Mobile WiMAX".
Uses
The bandwidth and range of WiMAX make it suitable for the following potential applications:
• Providing portable mobile broadband connectivity across cities and countries through a variety of devices.
• Providing a wireless alternative to cable and DSL for "last mile" broadband access.
• Providing data, telecommunications (VoIP) and IPTV services (triple play).
• Providing a source of Internet connectivity as part of a business continuity plan.
Broadband
Companies are deploying WiMAX to provide mobile broadband or at-home broadband connectivity across whole cities or countries. In many cases this has resulted in competition in markets which typically only had access to broadband through an existing incumbent DSL (or similar) operator.
Additionally, given the relatively low cost to deploy a WiMAX network (in comparison to GSM, DSL or Fiber-Optic), it is now possible to provide broadband in places where it may have not been economically viable.
Backhaul
WiMAX is a possible replacement candidate for cellular phone technologies such as GSM and CDMA, or can be used as an overlay to increase capacity. Fixed WiMAX is also considered as a wireless backhaul technology for 2G, 3G, and 4G networks in both developed and developing nations.[6][7]
In North America, backhaul for urban cellular operations is typically provided via one or more copper wire line T1 connections, whereas remote cellular operations are sometimes backhauled via satellite. In most other regions, urban and rural backhaul is usually provided by microwave links. (The exception to this is where the network is operated by an incumbent with ready access to the copper network, in which case T1 lines may be used.) WiMAX is a broadband platform and as such has much more substantial backhaul bandwidth requirements than legacy cellular applications. Therefore, traditional copper wire line backhaul solutions are not appropriate. Consequently the use of wireless microwave backhaul is on the rise in North America and existing microwave backhaul links in all regions are being upgraded.[8] Capacities of between 34 Mbit/s and 1 Gbit/s[citation needed] are routinely being deployed with latencies in the order of 1 ms. In many cases, operators are aggregating sites using wireless technology and then presenting traffic on to fiber networks where convenient.
Triple-play
WiMAX supports the technologies that make triple-play service offerings possible (such as Quality of Service and Multicasting).
As a result, it is possible for a WiMAX operator to not only provide high-speed broadband internet access, but also VoIP and IPTV services to customers with relative ease. This enables a WiMAX service to be a replacement for DSL, Cable and Telephony services.
On May 7, 2008 in the United States, Sprint Nextel, Google, Intel, Comcast, Bright House, and Time Warner announced a pooling of an average of 120 MHz of spectrum and merged with Clearwire to form a company which will take the name Clear. The new company hopes to benefit from combined services offerings and network resources as a springboard past its competitors. The cable companies will provide media services to other partners while gaining access to the wireless network as a Mobile virtual network operator to provide triple-play services.
Some analysts have questioned how the deal will work out: Although fixed-mobile convergence has been a recognized factor in the industry, prior attempts to form partnerships among wireless and cable companies have generally failed to lead to significant benefits to the participants. Other analysts point out that as wireless progresses to higher bandwidth, it inevitably competes more directly with cable and DSL, inspiring competitors into collaboration. Also, as wireless broadband networks grow denser and usage habits shift, the need for increased backhaul and media service will accelerate, therefore the opportunity to leverage cable assets is expected to increase.
Rapid deployment
• WiMAX access was used to assist with communications[citation needed] in Aceh, Indonesia, after the tsunami in December 2004. All communication infrastructure in the area, other than amateur radio, was destroyed[citation needed], making the survivors unable to communicate with people outside the disaster area and vice versa. WiMAX provided broadband access that helped regenerate communication to and from Aceh.[citation needed]
• WiMAX hardware was donated by Intel Corporation to assist the Federal Communications Commission (FCC) and FEMA in their communications efforts in the areas affected by Hurricane Katrina.[9] In practice, volunteers used mainly self-healing mesh, Voice over Internet Protocol (VoIP), and a satellite uplink combined with Wi-Fi on the local link.[10]
Connecting to WiMAX
A WiMAX Gateway which provides VoIP, Ethernet and WiFi connectivity
A WiMAX USB modem for mobile internet
There are numerous devices on the market that provide connectivity to a WiMAX network. These are known as the "subscriber unit" (SU).
There is an increasing focus on portable units. This includes handsets (similar to cellular smartphones); PC peripherals (PC Cards or USB dongles); and embedded devices in laptops, which are now available for Wi-Fi services. In addition, there is much emphasis by operators on consumer electronics devices such as Gaming consoles, MP3 players and similar devices. It is notable that WiMAX is more similar to Wi-Fi than to 3G cellular technologies.
The WiMAX Forum website provides a list of certified devices. However, this is not a complete list of devices available as certified modules are embedded into laptops, MIDs (Mobile internet devices), and other private labeled devices.
WiMAX Gateways
WiMAX gateway devices are available as both indoor and outdoor versions from several manufacturers. Many of the WiMAX gateways that are offered by manufactures such as ZyXEL, Motorola, and Greenpacket are stand-alone self-install indoor units. Such devices typically sit near the customer's window with the best WiMAX signal, and provide:
• An integrated Wi-Fi access point to provide the WiMAX Internet connectivity to multiple devices throughout the home or business.
• Ethernet ports should you wish to connect directly to your computer or DVR instead.
• One or two PSTN telephone jacks to connect your land-line phone and take advantage of VoIP.
Indoor gateways are convenient, but radio losses mean that the subscriber may need to be significantly closer to the WiMAX base station than with professionally-installed external units.
Outdoor units are roughly the size of a laptop PC, and their installation is comparable to the installation of a residential satellite dish. A higher-gain directional outdoor unit will generally result in greatly increased range and throughput but with the obvious loss of practical mobility of the unit.
WiMAX Dongles
There are a variety of USB dongles on the market which provide connectivity to a WiMAX network. Generally these devices are connected to a notebook or netbook whilst on the go. Dongles typically have omnidirectional antennae which are of lower-gain compared to other devices, as such these devices are best used in areas of good coverage.
WiMAX Mobiles
HTC announced the first WiMAX enabled mobile phone, the Max 4G, on Nov 12th 2008.[11] The device was only available to certain markets in Russia on the Yota network.
HTC released the second WiMAX enabled mobile phone, the EVO 4G, March 23, 2010 at the CTIA conference in Las Vegas. The device made available on June 4, 2010[12] is capable of both EV-DO(3G) and WiMAX(4G) as well as simultaneous data & voice sessions. The device also has a front-facing camera enabling the use of video conversations.[13] A number of WiMAX Mobiles are expected to hit the US market in 2010.[14]
Technical information
Illustration of a WiMAX MIMO board
WiMAX and the IEEE 802.16 Standard
The current WiMAX revision is based upon IEEE Std 802.16e-2005,[15] approved in December 2005. It is a supplement to the IEEE Std 802.16-2004,[16] and so the actual standard is 802.16-2004 as amended by 802.16e-2005. Thus, these specifications need to be considered together.
IEEE 802.16e-2005 improves upon IEEE 802.16-2004 by:
• Adding support for mobility (soft and hard handover between base stations). This is seen as one of the most important aspects of 802.16e-2005, and is the very basis of Mobile WiMAX.
• Scaling of the Fast Fourier transform (FFT) to the channel bandwidth in order to keep the carrier spacing constant across different channel bandwidths (typically 1.25 MHz, 5 MHz, 10 MHz or 20 MHz). Constant carrier spacing results in a higher spectrum efficiency in wide channels, and a cost reduction in narrow channels. Also known as Scalable OFDMA (SOFDMA). Other bands not multiples of 1.25 MHz are defined in the standard, but because the allowed FFT subcarrier numbers are only 128, 512, 1024 and 2048, other frequency bands will not have exactly the same carrier spacing, which might not be optimal for implementations.
• Advanced antenna diversity schemes, and hybrid automatic repeat-request (HARQ)
• Adaptive Antenna Systems (AAS) and MIMO technology
• Denser sub-channelization, thereby improving indoor penetration
• Introducing Turbo Coding and Low-Density Parity Check (LDPC)
• Introducing downlink sub-channelization, allowing administrators to trade coverage for capacity or vice versa
• Fast Fourier transform algorithm
• Adding an extra QoS class for VoIP applications.
SOFDMA (used in 802.16e-2005) and OFDM256 (802.16d) are not compatible thus equipment will have to be replaced if an operator is to move to the later standard (e.g., Fixed WiMAX to Mobile WiMAX).
Physical layer
The original version of the standard on which WiMAX is based (IEEE 802.16) specified a physical layer operating in the 10 to 66 GHz range. 802.16a, updated in 2004 to 802.16-2004, added specifications for the 2 to 11 GHz range. 802.16-2004 was updated by 802.16e-2005 in 2005 and uses scalable orthogonal frequency-division multiple access (SOFDMA) as opposed to the fixed orthogonal frequency-division multiplexing (OFDM) version with 256 sub-carriers (of which 200 are used) in 802.16d. More advanced versions, including 802.16e, also bring multiple antenna support through MIMO (See WiMAX MIMO). This brings potential benefits in terms of coverage, self installation, power consumption, frequency re-use and bandwidth efficiency.
MAC (data link) layer
The WiMAX MAC uses a scheduling algorithm for which the subscriber station needs to compete only once for initial entry into the network. After network entry is allowed, the subscriber station is allocated an access slot by the base station. The time slot can enlarge and contract, but remains assigned to the subscriber station, which means that other subscribers cannot use it. In addition to being stable under overload and over-subscription, the scheduling algorithm can also be more bandwidth efficient. The scheduling algorithm also allows the base station to control Quality of service (QoS) parameters by balancing the time-slot assignments among the application needs of the subscriber stations.
Deployment
As a standard intended to satisfy needs of next-generation data networks (4G), WiMAX is distinguished by its dynamic burst algorithm modulation adaptive to the physical environment the RF signal travels through. Modulation is chosen to be more spectrally efficient (more bits per OFDM/SOFDMA symbol). That is, when the bursts have a high signal strength and a high carrier to noise plus interference ratio (CINR), they can be more easily decoded using digital signal processing (DSP). In contrast, operating in less favorable environments for RF communication, the system automatically steps down to a more robust mode (burst profile) which means fewer bits per OFDM/SOFDMA symbol; with the advantage that power per bit is higher and therefore simpler accurate signal processing can be performed.
Burst profiles are used inverse (algorithmically dynamic) to low signal attenuation; meaning throughput between clients and the base station is determined largely by distance. Maximum distance is achieved by the use of the most robust burst setting; that is, the profile with the largest MAC frame allocation trade-off requiring more symbols (a larger portion of the MAC frame) to be allocated in transmitting a given amount of data than if the client were closer to the base station.
The client's MAC frame and their individual burst profiles are defined as well as the specific time allocation. However, even if this is done automatically then the practical deployment should avoid high interference and multipath environments. The reason for which is obviously that too much interference causes the network function poorly and can also misrepresent the capability of the network.
The system is complex to deploy as it is necessary to track not only the signal strength and CINR (as in systems like GSM) but also how the available frequencies will be dynamically assigned (resulting in dynamic changes to the available bandwidth.) This could lead to cluttered frequencies with slow response times or lost frames.
As a result the system has to be initially designed in consensus with the base station product team to accurately project frequency use, interference, and general product functionality.
Integration with an IP-based network
The WiMAX Forum WiMAX Architecture
The WiMAX Forum has proposed an architecture that defines how a WiMAX network can be connected with an IP based core network, which is typically chosen by operators that serve as Internet Service Providers (ISP); Nevertheless the WiMAX BS provide seamless integration capabilities with other types of architectures as with packet switched Mobile Networks.
The WiMAX forum proposal defines a number of components, plus some of the interconnections (or reference points) between these, labeled R1 to R5 and R8:
• SS/MS: the Subscriber Station/Mobile Station
• ASN: the Access Service Network[17]
• BS: Base station, part of the ASN
• ASN-GW: the ASN Gateway, part of the ASN
• CSN: the Connectivity Service Network
• HA: Home Agent, part of the CSN
• AAA: Authentication, Authorization and Accounting Server, part of the CSN
• NAP: a Network Access Provider
• NSP: a Network Service Provider
It is important to note that the functional architecture can be designed into various hardware configurations rather than fixed configurations. For example, the architecture is flexible enough to allow remote/mobile stations of varying scale and functionality and Base Stations of varying size - e.g. femto, pico, and mini BS as well as macros.
Spectrum allocation
There is no uniform global licensed spectrum for WiMAX, however the WiMAX Forum has published three licensed spectrum profiles: 2.3 GHz, 2.5 GHz and 3.5 GHz, in an effort to drive standardisation and decrease cost.
In the USA, the biggest segment available is around 2.5 GHz,[18] and is already assigned, primarily to Sprint Nextel and Clearwire. Elsewhere in the world, the most-likely bands used will be the Forum approved ones, with 2.3 GHz probably being most important in Asia. Some countries in Asia like India and Indonesia will use a mix of 2.5 GHz, 3.3 GHz and other frequencies. Pakistan's Wateen Telecom uses 3.5 GHz.
Analog TV bands (700 MHz) may become available for WiMAX usage, but await the complete roll out of digital TV, and there will be other uses suggested for that spectrum. In the USA the FCC auction for this spectrum began in January 2008 and, as a result, the biggest share of the spectrum went to Verizon Wireless and the next biggest to AT&T.[19] Both of these companies have stated their intention of supporting LTE, a technology which competes directly with WiMAX. EU commissioner Viviane Reding has suggested re-allocation of 500–800 MHz spectrum for wireless communication, including WiMAX.[20]
WiMAX profiles define channel size, TDD/FDD and other necessary attributes in order to have inter-operating products. The current fixed profiles are defined for both TDD and FDD profiles. At this point, all of the mobile profiles are TDD only. The fixed profiles have channel sizes of 3.5 MHz, 5 MHz, 7 MHz and 10 MHz. The mobile profiles are 5 MHz, 8.75 MHz and 10 MHz. (Note: the 802.16 standard allows a far wider variety of channels, but only the above subsets are supported as WiMAX profiles.)
Since October 2007, the Radio communication Sector of the International Telecommunication Union (ITU-R) has decided to include WiMAX technology in the IMT-2000 set of standards.[21] This enables spectrum owners (specifically in the 2.5-2.69 GHz band at this stage) to use WiMAX equipment in any country that recognizes the IMT-2000.
Spectral efficiency
One of the significant advantages of advanced wireless systems such as WiMAX is spectral efficiency. For example, 802.16-2004 (fixed) has a spectral efficiency of 3.7 (bit/s)/Hertz, and other 3.5–4G wireless systems offer spectral efficiencies that are similar to within a few tenths of a percent. The notable advantage of WiMAX comes from combining SOFDMA with smart antenna technologies. This multiplies the effective spectral efficiency through multiple reuse and smart network deployment topologies. The direct use of frequency domain organization simplifies designs using MIMO-AAS compared to CDMA/WCDMA methods, resulting in more effective systems.
Inherent Limitations
A commonly-held misconception is that WiMAX will deliver 70 Mbit/s over 50 kilometers. Like all wireless technologies, WiMAX can either operate at higher bitrates or over longer distances but not both: operating at the maximum range of 50 km (31 miles) increases bit error rate and thus results in a much lower bitrate. Conversely, reducing the range (to under 1 km) allows a device to operate at higher bitrates.
A recent city-wide deployment of WiMAX in Perth, Australia, has demonstrated that customers at the cell-edge with an indoor CPE typically obtain speeds of around 1–4 Mbit/s, with users closer to the cell tower obtaining speeds of up to 30 Mbit/s.[citation needed]
Like all wireless systems, available bandwidth is shared between users in a given radio sector, so performance could deteriorate in the case of many active users in a single sector. However, with adequate capacity planning and the use of WiMAX's Quality of Service, a minimum guaranteed throughput for each subscriber can be put in place. In practice, most users will have a range of 4-8 Mbit/s services and additional radio cards will be added to the base station to increase the number of users that may be served as required.
Silicon implementations
A critical requirement for the success of a new technology is the availability of low-cost chipsets and silicon implementations.
WiMAX has a strong silicon ecosystem with a number of specialized companies producing baseband ICs and integrated RFICs for implementing full-featured WiMAX Subscriber Stations in the 2.3, 2.5 and 3.5Ghz band (refer to 'Spectrum allocation' above). It is notable that most of the major semiconductor companies have not developed WiMAX chipsets of their own and have instead chosen to invest in and/or utilise the well developed products from smaller specialists or start-up suppliers. These companies include but not limited to Beceem, Sequans and PicoChip. The chipsets from these companies are used in the majority of WiMAX devices.
Intel Corporation is a leader in promoting WiMAX, but has limited its WiMAX chipset development and instead chosen to invest in these specialized companies producing silicon compatible with the various WiMAX deployments throughout the globe.
Comparison with Wi-Fi
Comparisons and confusion between WiMAX and Wi-Fi are frequent because both are related to wireless connectivity and Internet access.
• WiMAX is a long range system, covering many kilometres, that uses licensed or unlicensed spectrum to deliver connection to a network, in most cases the Internet.
• Wi-Fi uses unlicensed spectrum to provide access to a local network.
• Wi-Fi is more popular in end user devices.
• Wi-Fi runs on the Media Access Control's CSMA/CA protocol, which is connectionless and contention based, whereas WiMAX runs a connection-oriented MAC.
• WiMAX and Wi-Fi have quite different quality of service (QoS) mechanisms:
o WiMAX uses a QoS mechanism based on connections between the base station and the user device. Each connection is based on specific scheduling algorithms.
o Wi-Fi uses contention access - all subscriber stations that wish to pass data through a wireless access point (AP) are competing for the AP's attention on a random interrupt basis. This can cause subscriber stations distant from the AP to be repeatedly interrupted by closer stations, greatly reducing their throughput.
• Both 802.11 and 802.16 define Peer-to-Peer (P2P) and ad hoc networks, where an end user communicates to users or servers on another Local Area Network (LAN) using its access point or base station. However, 802.11 supports also direct ad hoc or peer to peer networking between end user devices without an access point while 802.16 end user devices must be in range of the base station.
Wi-Fi and WiMAX are complementary. WiMAX network operators typically provide a WiMAX Subscriber Unit which connects to the metropolitan WiMAX network and provides Wi-Fi within the home or business for local devices (e.g., Laptops, Wi-Fi Handsets, smartphones) for connectivity. This enables the user to place the WiMAX Subscriber Unit in the best reception area (such as a window), and still be able to use the WiMAX network from any place within their residence.
Conformance testing
TTCN-3 test specification language is used for the purposes of specifying conformance tests for WiMAX implementations. The WiMAX test suite is being developed by a Specialist Task Force at ETSI (STF 252).[22]
Associations
WiMAX Forum
The WiMAX Forum is a non profit organization formed to promote the adoption of WiMAX compatible products and services.[23]
A major role for the organization is to certify the interoperability of WiMAX products.[24] Those that pass conformance and interoperability testing achieve the "WiMAX Forum Certified" designation, and can display this mark on their products and marketing materials. Some vendors claim that their equipment is "WiMAX-ready", "WiMAX-compliant", or "pre-WiMAX", if they are not officially WiMAX Forum Certified.
Another role of the WiMAX Forum is to promote the spread of knowledge about WiMAX. In order to do so, it has a certified training program that is currently offered in English and French. It also offers a series of member events and endorses some industry events.
WiMAX Spectrum Owners Alliance
WiSOA logo
WiSOA logo
WiSOA was the first global organization composed exclusively of owners of WiMAX spectrum with plans to deploy WiMAX technology in those bands. WiSOA focussed on the regulation, commercialisation, and deployment of WiMAX spectrum in the 2.3–2.5 GHz and the 3.4–3.5 GHz ranges. WiSOA merged with the Wireless Broadband Alliance in April 2008. [25]
Competing technologies
Speed vs. Mobility of wireless systems: Wi-Fi, HSPA, UMTS, GSM
Within the marketplace, WiMAX's main competition comes from existing, widely deployed wireless systems such as UMTS, CDMA2000, existing Wi-Fi and mesh networking.
In the future, competition will be from the evolution of the major cellular standards to so-called 4G, high-bandwidth, low-latency, all-IP networks with voice services built on top. The worldwide move to 4G for GSM/UMTS and AMPS/TIA (including CDMA2000) is the 3GPP Long Term Evolution effort. However, it has been noted that the likely performance difference between WiMAX as it stands today and LTE when it is eventually commercially available in 2–3 years time, will be negligible.[citation needed]
LTE is expected to be ratified at the end of 2010, with commercial implementations becoming viable within the next two years.. End of 2009 TeliaSonera started commercial deployment in Oslo and Stockholm, In Denmark the 3 big telecoms are upgrading their network, and will make LTE available during 2010.
In some areas of the world, the wide availability of UMTS and a general desire for standardization has meant spectrum has not been allocated for WiMAX: in July 2005, the EU-wide frequency allocation for WiMAX was blocked.
Harmonization
Early WirelessMAN standards, the European standard HiperMAN and Korean standard WiBro have been harmonized as part of WiMAX and are no longer seen as competition but as complementary. All networks now being deployed in South Korea, the home of the WiBro standard, are now WiMAX.
Comparison
Main article: Comparison of wireless data standards
The neutrality of this article is disputed. Please see the discussion on the talk page. Please do not remove this message until the dispute is resolved. (January 2009)
The following table should be treated with caution because it only shows peak rates which are potentially very misleading. In addition, the comparisons listed are not normalized by physical channel size (i.e., spectrum used to achieve the listed peak rates); this obfuscates spectral efficiency and net through-put capabilities of the different wireless technologies listed below.
Comparison of Mobile Internet Access methods
mobility up to 200mph (350km/h)
10.6
15.9
3.6
5.4
extended range 34 miles (55km)
(11n)
(Supports 600Mbps @ 40MHz channel width)
Antenna, RF front end enhancements and minor protocol timer tweaks have helped deploy long range P2P networks compromising on radial coverage, throughput and/or spectra efficiency (310km & 382km).
Speed: 250kmph
Spectral Efficiency: 13 bits/s/Hz/cell
Spectrum Reuse Factor: "1"
HSDPA+HSUPA
HSPA+
CDMA/FDD/MIMO
14.4
56
5.76
22
EV-DO 1x Rev.A
EV-DO Rev.B
3.1
4.9xN
1.8
1.8xN
Notes: All speeds are theoretical maximums and will vary by a number of factors, including the use of external antennae, distance from the tower and the ground speed (e.g. communications on a train may be poorer than when standing still). Usually the bandwidth is shared between several terminals. The performance of each technology is determined by a number of constraints, including the spectral efficiency of the technology, the cell sizes used, and the amount of spectrum available. For more information, see Comparison of wireless data standards. See also Comparison of mobile phone standards, Spectral efficiency comparison table and OFDM system comparison table.
Future development
The IEEE 802.16m [1] standard is the core technology for the proposed WiMAX Release 2, which enables more efficient, faster, and more converged data communications. The IEEE 802.16m standard has been submitted to the ITU for IMT-Advanced standardization[26]. IEEE 802.16m is one of the major candidates for IMT-Advanced technologies by ITU. Among many enhancements, IEEE 802.16m systems can provide four times faster[clarification needed] data speed than the current WiMAX Release 1 based on IEEE 802.16e technology.
WiMAX Release 2 will provide strong backward compatibility with Release 1 solutions. It will allow current WiMAX operators to migrate their Release 1 solutions to Release 2 by upgrading channel cards or software of their systems. Also, the subscribers who use currently available WiMAX devices can communicate with new WiMAX Release 2 systems without difficulty.
It is anticipated that in a practical deployment, using 4X2 MIMO in the urban microcell scenario with only a single 20-MHz TDD channel available system wide, the 802.16m system can support both 120 Mbit/s downlink and 60 Mbit/s uplink per site simultaneously. It is expected that the WiMAX Release 2 will be available commercially in the 2011-2012 timeframe.[27]
Interference
A field test conducted by SUIRG (Satellite Users Interference Reduction Group) with support from the U.S. Navy, the Global VSAT Forum, and several member organizations yielded results showing interference at 12 km when using the same channels for both the WiMAX systems and satellites in C-band.[28] The WiMAX Forum has yet to respond.
Deployments
Main article: List of deployed WiMAX networks
As example, Korea launched Wimax at 2nd quarter of 2006 and then launched HSPA one quarter after launched Wimax. At the end of 2008 there were 8.4 million HSPA subscribers and 350,000 Wimax subscribers in Korea. Almost all of HSPA subscribers come from 2G and 3G users who have been tempted to upgrade to new devices by high subsidies, whereas Wimax subscribers almost all are newcomers. Deployment of Wimax is still limited (spotted), whereas there are well over 100 countries where HSPA networks are deployed, and even where there is no HSPA coverage there is backward compatibility (using HSPA devices) to pre-existing networks (GSM and WCDMA) with a roaming infrastructure already in place. In the mean time, the HSPA juggernaut looks unstoppable.[29]
As of April 2010, the WiMAX Forum claims there are over 558 WiMAX (fixed and mobile) networks deployed in over 147 countries.[30]
Yota is the largest WiMAX network operator in the world[31] but has announced that it will move new network deployments to LTE and, subsequently, change its existing networks as well.[32]
Internet access
| [hide]Internet access | ||||||||
|---|---|---|---|---|---|---|---|---|
| Network type | Wired | Wireless | ||||||
| Optical | Coaxial cable | Twisted pair | Phone line | Power line | Unlicensed terrestrial bands | Licensed terrestrial bands | Satellite | |
| LAN | Ethernet | G.hn | Ethernet | HomePNA · G.hn | G.hn | Wi-Fi · Bluetooth · DECT · Wireless USB | ||
| WAN | PON · Ethernet | DOCSIS | Ethernet | Dial-up · ISDN · DSL | BPL | Muni Wi-Fi | GPRS · iBurst · WiBro/WiMAX · UMTS-TDD, HSPA · EVDO · LTE | Satellite |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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