pment group (CDG) work on adoption and ease in deployment of 3G CDMA wireless systems. 9.9 WiMAX WiMAX (worldwide interoperability for microwave access) is a wireless broadband technology based on standard IEEE 802.16. It is a wireless alternative to cable modems, DSL, and T1/E1 links. The IEEE standard was named WiMAX by the WiMAX Forum to promote the IEEE standard for interoperability and deploy- ment. It can support voice, video, and internet data. The spectrum bands in which WiMAX usually operates include 2.3 GHz, 2.5 GHz, 3.5 GHz, and 5.8 GHz, with a speed of approximately 40 Mbps per wireless channel. Based on coverage, WiMAX is classified under MAN (metropolitan area network). WiMAX can offer both non-line-of-sight and line-of-sight service. In non- line-of-sight that operates at lower frequency range, an antenna on the personal com- puter communicates with WiMAX tower and in line-of-sight that operates at high frequencies, a dish antenna points directly at the WiMAX tower. It uses orthogonal frequency division multiple access (OFDM) as the modulation technique. WiMAX architecture can be split into three parts (see Figure 9.8). They are: Mobile station (MS): This is the user equipment or user terminal that the end user uses to access the WiMAX network. Access service network (ASN): This is the access network of WiMAX com- prising of base stations (BS) and one or more ASN GW (gateways). While the base station is responsible for providing the air interface with MS, the ASN gateways form the radio access network at the edge. Connectivity service network (CSN): This is the core network that offers the services and connectivity with other networks. It includes the AAA server for authentication, authorization, and accounting, the MIP-HA (mobile IP home agent), the services offered using supporting networks like IMS, operation support system/billing system that can be a part of the core or a stand-alone application and the gateways for protocol conversion and connectivity with other networks. IEEE 802.16 has a ne