Praise for Fundamentals of WiMAX

1.4 WiMAX and Other Broadband Wireless Technologies 15supported in 1x EV-DO. Similarly, development efforts are under way to support IP voice,video, and gaming, as well as multicast and broadcast services over UMTS/HSPA networks.It should also be noted that 3GPP is developing the next major revision to the 3G standards.The objective of this long-term evolution (LTE) is to be able to support a peak data rate of100Mbps in the downlink and 50Mbps in the uplink, with an average spectral efficiency that isthree to four times that of Release 6 HSPA. In order to achieve these high data rates and spectralefficiency, the air interface will likely be based on OFDM/OFDMA and MIMO (multiple input/multiple output), with similarities to WiMAX.Similarly, 3GPP2 also has longer-term plans to offer higher data rates by moving to higherbandwidthoperation. The objective is to support up to 70Mbps to 200Mbps in the downlink and up to30Mbps to 45Mbps in the uplink in EV-DO Revision C, using up to 20MHz of bandwidth. It shouldbe noted that neither LTE nor EV-DO Rev C systems are expected to be available until about 2010.1.4.2 Wi-Fi SystemsIn addition to 3G, Wi-Fi based-systems may be used to provide broadband wireless. Wi-Fi isbased on the IEEE 802.11 family of standards and is primarily a local area networking (LAN)technology designed to provide in-building broadband coverage. Current Wi-Fi systems basedon IEEE 802.11a/g support a peak physical-layer data rate of 54Mbps 3 and typically provideindoor coverage over a distance of 100 feet. Wi-Fi has become the defacto standard for “lastfeet” broadband connectivity in homes, offices, and public hotspot locations. In the past coupleof years, a number of municipalities and local communities around the world have taken the initiativeto get Wi-Fi systems deployed in outdoor settings to provide broadband access to citycenters and metrozones as well as to rural and underserved areas. It is this application of Wi-Fithat overlaps with the fixed and nomadic application space of WiMAX.Metro-area Wi-Fi deployments rely on higher power transmitters that are deployed on lamppostsor building tops and radiating at or close to the maximum allowable power limits for operatingin the license-exempt band. Even with high power transmitters, Wi-Fi systems can typicallyprovide a coverage range of only about 1,000 feet from the access point. Consequently, metro-Wi-Fi applications require dense deployment of access points, which makes it impractical forlarge-scale ubiquitous deployment. Nevertheless, they could be deployed to provide broadbandaccess to hotzones within a city or community. Wi-Fi offers remarkably higher peak data ratesthan do 3G systems, primarily since it operates over a larger 20MHz bandwidth. The inefficientCSMA (carrier sense multiple access) protocol used by Wi-Fi, along with the interference constraintsof operating in the license-exempt band, is likely to significantly reduce the capacity ofoutdoor Wi-Fi systems. Further, Wi-Fi systems are not designed to support high-speed mobility.One significant advantage of Wi-Fi over WiMAX and 3G is the wide availability of terminaldevices. A vast majority of laptops shipped today have a built-in Wi-Fi interface. Wi-Fi interfaces3. This typically translates to only around 20Mbps to 25Mbps layer 2 peak throughput owing toCSMA overhead.