entifier [12], and can either be collocated with the BS or separate from the BS across R6 reference point. There are two types of PCs: Anchor PC that maintains the updated location information of the MS; and Relay PC that participates in relaying of paging and location management messages between paging agent and the anchor PC. Location Location Register Register Paging Paging Controller Controller Paging Paging Paging Paging Paging Paging Agent 1 Agent 2 Agent 3 Agent 4 Agent 5 Agent 6 Paging Group 1 Paging Group 2 Paging Group 3 FIGURE 2-7 The paging network reference model CHAPTER 2 WiMAX Network Architecture Paging Agent (PA) is a functional entity that manages the interaction between the PC and the IEEE 802.16-2009 standard specified paging-related functionality implemented in the BS. A PA is collocated with the BS. Paging Group (PG), as defined in the IEEE 802.16-2009 standard, consists of one or more Paging Agents. A Paging Group resides entirely within a NAP boundary and is managed and provisioned by the network operator. Location Register (LR) is a distributed database with each instance corresponding to an Anchor PC. Location registers contain information about mobile stations in Idle State. The information for each MS includes current Paging Group ID (PGID), paging cycle, paging offset, last reported BS Identifier (BS ID), last reported Relay PC ID, etc [5]. There are typically multiple paging groups inside an operator's network. A BS and its corresponding collocated PA can be part of more than one paging group. The paging controller can be collocated with the BS. The paging control messages between PCs are exchanged across R4 reference point. The LR consists of a location database which is accessible through PC and tracks the current paging group of each mobile station in Idle State within the network. It also stores the context information required for paging. When the MS moves across paging groups, location update occurs across PCs via R6 and/or R4 reference points, and information is updated in the