9 [8]. The user demand for broadband wireless services and applications are continually growing. In particular, users expect a dynamic, continuing stream of new applications, capabilities, and services that are ubiquitous and available across a range of devices using a single subscription and a single or unique identity. Offering customized and ubiquitous services based on diverse individual needs through versatile communication systems will require certain considerations in the technology design and deployment. A number of important factors are accelerating the adoption of wireless data services. These include increased user demand for wireless multimedia services, advances in smart-phone technolo- gies, and global coverage of broadband wired and wireless access. In the meantime, application and content providers are either optimizing their offerings or developing new applications to address the needs and expectations of fixed and mobile users. Wireless multimedia applications are growing far more rapidly than voice, and are increas- ingly dominating network traffic. There has been a gradual change from predominantly circuit- switched to packet-based and all-IP networks since the beginning of this millennium [9]. This change will provide the user with the ability to more efficiently utilize multimedia services including e-mail, file transfers, IP TV, VoIP, interactive gaming, messaging, and distribution services. These services are either symmetrical or asymmetrical and real-time or non real-time. They require wider frequency bandwidths, lower transmission and processing latencies, and higher data throughputs. 1.1 Mobile broadband wireless access technologies It is envisioned that within the next decade a large number of the world population would have access to advanced mobile communication devices. The statistics suggest that the number of broad- band wireless service subscribers can exceed two billion in the next few years [9]. There are already more portable handsets than either fixed line telephones or wire