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WiMAX is an industry trade organization formed by leading communications component and equipment companies to promote and certify compatibility and interoperability of broadband wireless access equipment that conforms to the IEEE 802.16 and ETSI HIPERMAN standards.
The 802.16a standard is a wireless metropolitan area network (MAN) technology that will provide a wireless alternative to cable, DSL and T1/E1 for last mile broadband access. It will also be used as complimentary technology to connect 802.11 hot spots to the Internet.
WiMAX will accelerate and increase the success of future interoperability testing by providing tools for conformance testing. Tools can be used during the equipment maker's system development process to ensure conformance with the standards-based product roadmap as it evolves.
Members include leading Operators, Equipment and Component makers (see list at end) WiMAX was formed in April 2001, in anticipation of the publication of the original 10-66 GHz IEEE 802.16 specifications. WiMAX is to 802.16 as the Wi-Fi Alliance is to 802.11.[c]
A standard by itself is not enough to enable mass adoption. WiMAX has stepped forward to help solve barriers to adoption, such as interoperability and cost of deployment. WiMAX will help ignite the wireless MAN industry, by defining and conducting interoperability testing and labeling vendor systems with a "WiMAX Certified™" label once testing has been completed successfully.
The 802.16a standard is a wireless metropolitan area network (MAN) technology that will provide a wireless alternative to cable, DSL and T1/E1 for last mile broadband access. It will also be used as complimentary technology to connect 802.11 hot spots to the Internet.
WiMAX will accelerate and increase the success of future interoperability testing by providing tools for conformance testing. Tools can be used during the equipment maker's system development process to ensure conformance with the standards-based product roadmap as it evolves.
Members include leading Operators, Equipment and Component makers (see list at end) WiMAX was formed in April 2001, in anticipation of the publication of the original 10-66 GHz IEEE 802.16 specifications. WiMAX is to 802.16 as the Wi-Fi Alliance is to 802.11.[c]
A standard by itself is not enough to enable mass adoption. WiMAX has stepped forward to help solve barriers to adoption, such as interoperability and cost of deployment. WiMAX will help ignite the wireless MAN industry, by defining and conducting interoperability testing and labeling vendor systems with a "WiMAX Certified™" label once testing has been completed successfully.
[Figure 1. Wireless Internet using WiMAX
The race is on in the service provider community to offer "triple play" (voice, video and data) or "quadruple play" (voice, video data as well as mobile voice and data).
Some service providers are attempting to do this with 3 or 4 dissimilar networks as illustrated in the figure below. For example, at the time of this writing, Qwest Communications Inter-national sold their own voice and broadband data for the residential market, Dish Net-works for satellite TV and resells Sprint Nextel cellular service.
Reselling other service providers services does not generate the profit margins as selling one's own services does. Given the vertical orientation of legacy systems like cable TV (only does TV), circuit-switched voice services (like cell phone networks-designed almost entirely for voice), it is difficult and expensive to offer more than one type of service on any one "stovepipe" network. The solution is IP Multimedia Subsystems (IMS).
Some service providers are attempting to do this with 3 or 4 dissimilar networks as illustrated in the figure below. For example, at the time of this writing, Qwest Communications Inter-national sold their own voice and broadband data for the residential market, Dish Net-works for satellite TV and resells Sprint Nextel cellular service.
Reselling other service providers services does not generate the profit margins as selling one's own services does. Given the vertical orientation of legacy systems like cable TV (only does TV), circuit-switched voice services (like cell phone networks-designed almost entirely for voice), it is difficult and expensive to offer more than one type of service on any one "stovepipe" network. The solution is IP Multimedia Subsystems (IMS).
[Figure 2. Legacy "stovepipe" infrastructure cannot easily offer more than one service]
IMS Vision
The vision for IMS is that an all-IP network will allow a subscriber to access a multitude of services regardless of how they access the network (cable TV modem, DSL, cellular, Wi-Fi, or WiMAX). Very simply put, the subscriber will be able to access any service on any device
The vision for IMS is that an all-IP network will allow a subscriber to access a multitude of services regardless of how they access the network (cable TV modem, DSL, cellular, Wi-Fi, or WiMAX). Very simply put, the subscriber will be able to access any service on any device
[Figure 3. IMS allows a subscriber to access any service on any device using any form of access]
IMS began as a concept in the cell phone industry to offer voice, short messaging service (SMS) and video on cell phones. It utilizes a simple three-layer architecture consisting of the Connectivity Layer (similar to the physical layer in the OSI model), a Control Layer, which provides switching and signaling functions, and the Service Layer where applications such as IPTV and VoIP features are offered.
Running parallel to those function layers are a range of support systems, which control security and QS across the network. The signaling protocol known as Session Initiation Protocol (SIP) provides signaling across the network.
Running parallel to those function layers are a range of support systems, which control security and QS across the network. The signaling protocol known as Session Initiation Protocol (SIP) provides signaling across the network.
Fixed Wireless(IEEE 802.16-2004) Applications
Perhaps the most lucrative application for WiMAX is that of substitute for the telephone company's copper wire. This is achieved through fixed wireless solutions. A majority of US businesses and residences receive their telephone service and internet access via the telephone company's copper wires. A T1 data line from the telephone company may re-tail for $800/month in many US cities. About 50% of that expense is "local loop" charges or paying to use the telephone company's copper wire to access a wider network. As the diagram below illustrates, a WiMAX service provider could purchase the bandwidth equivalent of a T1 (1.54 Mbps) at, say, $45 and resell to an enterprise customer for $400. Through oversubscription (overselling), that service provider could realize a multiple of that profit.
Perhaps the most lucrative application for WiMAX is that of substitute for the telephone company's copper wire. This is achieved through fixed wireless solutions. A majority of US businesses and residences receive their telephone service and internet access via the telephone company's copper wires. A T1 data line from the telephone company may re-tail for $800/month in many US cities. About 50% of that expense is "local loop" charges or paying to use the telephone company's copper wire to access a wider network. As the diagram below illustrates, a WiMAX service provider could purchase the bandwidth equivalent of a T1 (1.54 Mbps) at, say, $45 and resell to an enterprise customer for $400. Through oversubscription (overselling), that service provider could realize a multiple of that profit.
PSTN bypass for fixed wireless T1/E1/DS3 substitute
[Figure 4. WiMAX offers a substitute for the telephone company's T1/E1 or DS3]
Satisfying the growing demand for Broadband Wireless Access (BWA) in underserved markets has been a continuing challenge for service providers, due to the absence of a truly global standard. A standard that would enable companies to build systems that will effectively reach underserved business and residential markets in a manner that supports infrastructure build outs comparable to cable, DSL, and fiber. For years, the wildly successful 802.11x or WiFi wireless LAN technology has been used in BWA applications along with a host of proprietary based solutions. When the WLAN technology was examined closely, it was evident that the overall design and feature set available was not well suited for outdoor BWA applications. It could be done, it is being done, but with limited capacity in terms of bandwidth and subscribers, range and a host of other issues made it clear this approach while a great fit for indoor WLAN was a poor fit for outdoor BWA.
This analysis and review was conducted by the IEEE and it was decided that a new, more complex and fully developed standard would be required to address both the physical layer environment (outdoor versus indoor RF transmissions) and the Quality of Service (QoS) needs demanded by the BWA and last mile access market. The IEEE conducted a multi-year effort to develop this new standard, culminating in final approval of the 802.16a Air-Interface Specification in January 2003. This standard has since received broad industry support from leading equipment makers. Many WiMAX company members are active in both the IEEE 802.16 standards development and the IEEE 802.11 efforts for Wireless LAN, and envision the combination of 802.16a and 802.11 creating a complete wireless solution for delivering high speed Internet access to businesses, homes, and WiFi hot spots. The 802.16a standard delivers carrierclass performance in terms of robustness and QoS and has been designed from the ground up to deliver a suite of services over a scalable, long range, high capacity "last mile" wireless communications for carriers and service providers around the world.
This analysis and review was conducted by the IEEE and it was decided that a new, more complex and fully developed standard would be required to address both the physical layer environment (outdoor versus indoor RF transmissions) and the Quality of Service (QoS) needs demanded by the BWA and last mile access market. The IEEE conducted a multi-year effort to develop this new standard, culminating in final approval of the 802.16a Air-Interface Specification in January 2003. This standard has since received broad industry support from leading equipment makers. Many WiMAX company members are active in both the IEEE 802.16 standards development and the IEEE 802.11 efforts for Wireless LAN, and envision the combination of 802.16a and 802.11 creating a complete wireless solution for delivering high speed Internet access to businesses, homes, and WiFi hot spots. The 802.16a standard delivers carrierclass performance in terms of robustness and QoS and has been designed from the ground up to deliver a suite of services over a scalable, long range, high capacity "last mile" wireless communications for carriers and service providers around the world.
[Figure 5.Usage Model of WiMAX]
In BWA, applications include residential broadband access-- DSL-level service for SOHO and small businesses, T1/E1 level service for enterprise, all supporting not just data but voice and video as well, wireless backhaul for hotspots andcellular tower backhaul service to name a few.
In reviewing the standard, the technical details and features that differentiate WiMAX certified equipment from WiFi or other technologies can best be illustrated by focusing on the two layers addressed in the standard, the physical (PHY) or RF transmissions and the media access control (MAC) layer design.
Some of the other PHY layer features of 802.16a that are instrumental in giving this technology the power to deliver robust performance in a broad range of channel environments are; flexible channel widths, adaptive burst profiles, forward error correction with concatenated Reed-Solomon and convolutional encoding, optional AAS (advanced antenna systems) to improve range/capacity, DFS (dynamic frequency selection)-which helps in minimizing interference, and STC (space-time coding) to enhance performance in fading environments through spatial diversity. Table 1 gives a high level overview of some of the PHY layer features of the IEEE 802.16a standard.
In reviewing the standard, the technical details and features that differentiate WiMAX certified equipment from WiFi or other technologies can best be illustrated by focusing on the two layers addressed in the standard, the physical (PHY) or RF transmissions and the media access control (MAC) layer design.
Some of the other PHY layer features of 802.16a that are instrumental in giving this technology the power to deliver robust performance in a broad range of channel environments are; flexible channel widths, adaptive burst profiles, forward error correction with concatenated Reed-Solomon and convolutional encoding, optional AAS (advanced antenna systems) to improve range/capacity, DFS (dynamic frequency selection)-which helps in minimizing interference, and STC (space-time coding) to enhance performance in fading environments through spatial diversity. Table 1 gives a high level overview of some of the PHY layer features of the IEEE 802.16a standard.
- 802.16a PHY Features
| Feature | Benefit |
| 256 point FFT OFDM waveform | Built in support for addressing multipath in outdoor |
| 256 point FFT OFDM waveform | Ensures a robust RF link while maximizing the number of bits/ second for each subscriber unit. |
| TDD and FDD duplexing support | Address varying worldwide regulations where one or both may be allowed |
| Flexible Channel sizes (e.g. 3.5MHz, 5MHz, 10MHz, etc) | Provides the flexibility necessary to operate in many different frequency bands with varying channel requirements around the world. |
| Designed to support smart antenna systems | Smart antennas are fast becoming more affordable, and as these costs come down their ability to suppress interference and increase system gain will become important to BWA deployments |
1. WiMAX Forum: http://www.wimaxforum.org
2. Intel WiMAX Site: http://www.intel.com/netcomms/technologies/wimax/index.htm
3. WiMAX overview : http://www.wimax.com/education/wimax/wimax_overview
4. WiMAX Whitepaper : http://www.wimaxforum.org/news/downloads/WiMAXWhitepaper.pdf
5. WiMAX Education : http://www.wimax.com/education/wimax
2. Intel WiMAX Site: http://www.intel.com/netcomms/technologies/wimax/index.htm
3. WiMAX overview : http://www.wimax.com/education/wimax/wimax_overview
4. WiMAX Whitepaper : http://www.wimaxforum.org/news/downloads/WiMAXWhitepaper.pdf
5. WiMAX Education : http://www.wimax.com/education/wimax
