 radio propagation characteristics of that environment. 1.2 INTRODUCTION TO THE IEEE 802.16 STANDARDS The development of standards in IEEE was assigned to the IEEE Standards Association. The activities of the IEEE-SA are administered by an elected board of governors. The development and maintenance of the standards are overseen by the IEEE-SA Standards Board, which manages the process, approves new projects, and further approves the balloted drafts as the IEEE standards. The IEEE 802 LAN/ MAN Standards Committee (also known as IEEE 802) has been in operation since March 1980. The objective of this group has been to develop LAN and MAN standards and protocols that are mapped to the lower layers (i.e., physical and data link layers) of the seven-layer Open System Interconnection (OSI) reference model (see Figure 1-3). The IEEE 802 splits the OSI data link layer into two sub-layers, namely Logical Link Control (LLC) and Medium Access Control (MAC) [24]. The most widely used standards are for the Ethernet family [25], Token Ring [26], Wireless LAN [27], Wireless 'The Open Systems Interconnection reference model (OSI) is an abstract description for layered communications and computer network protocol design which was developed as part of the Open Systems Interconnection initiative. The OSI model divides generic network architecture into seven layers which, from top to bottom, are defined as Application, Presentation, Session, Transport, Network, Data-Link, and Physical layers. 1.2 Introduction to the IEEE 802. 16 standards PAN [28], Wireless MAN [29,30], Bridging and Virtual Bridged LANs [31]. There are several active Working Groups under IEEE 802 that focus on different methods of broadband wireless and wired access. Table 1-3 shows the active IEEE 802 Working Groups and their charter. These groups operate under the IEEE 802 Executive Committee. As illustrated in Figure 1-5, the process for developing standards in IEEE 802 starts with submission of a proposal consisting of the Project Authorization Request (PAR), whi