ned to paging groups of different sizes based on user mobility. The MS monitors the paging message during tthe mobile station's paging listening interval. The start of the mobile station's paging listening interval is derived based on paging cycle and paging offset. The paging offset and paging cycle are defined in terms of the number of superframes (i.e., a collection of four radio frames). The mobile stations may be divided into logical groups in order to distribute the paging overhead. An MS may be assigned to one or more paging groups. If an MS is assigned to multiple paging groups, it may also be assigned multiple paging offsets within a paging cycle, where each paging offset corresponds to a separate paging group. The MS is not required to perform location update when it moves within its assigned paging groups. The assignment of multiple paging offsets to an MS allows monitoring of the paging message at a different paging offset when the MS is located in one of its paging groups. When an MS is assigned to more than one paging group, one of the paging groups called the Primary Paging Group and the others are known as Secondary Paging Groups. If an MS is assigned to one paging group, that paging group is considered the Primary Paging Group. When different paging offsets are assigned to an MS, the Primary Paging Offset is shorter than the Secondary Paging Offsets. The distance between two adjacent paging offsets should be long enough that the MS paged in the first paging offset can inform the network before the next paging offset in the same paging cycle, SO that the network avoids unnecessary paging of the MS in the next paging offset. An Idle State MS (while in a paging listening interval) wakes up at its primary paging offset and looks for primary Paging Group Identifier (PGIDs) information. If the MS does not detect the primary PGID, it will wake IVIde State and Idle Mode terms are used interchangeably in this book and in the literature. CHAPTER 6 The IEEE 802. 16m MAC CPS (Part I) Downlink VolP/Silence Do