wnlink HARQ ACK/NACK Insertion Descriptor (SID) Uplink VolP/SID transmission for Uplink transmission transmission Uplink HARQ ACK/NACK Downlink/Uplink allocation for Downlink transmission Downlink Uplink Downlink Uplink Downlink Uplink Downlink Uplink Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) No Persistent Allocation (Downlink and Uplink VolP Traffic) Downlink Uplink Downlink Uplink Downlink Uplink Downlink Uplink Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) Persistent Allocation (Uplink VolP Traffic only) Downlink Uplink Downlink Uplink Downlink Uplink Downlink Uplink Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) Persistent Allocation (Downlink VolP Traffic) Downlink Uplink Downlink Uplink Downlink Uplink Downlink Uplink Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) Persistent Allocation (Downlink SID Packets) FIGURE 6-21 Sleep mode operation for VolP (example) [25] during its secondary paging offset in the same paging cycle. If the MS can find neither primary nor secondary PGIDs, it will perform a location update. The BS transmits the list of PGIDs at predetermined locations. The PGID information should be received during a mobile station's paging listening interval. The paging message includes identifi- cation of the mobile stations (i.e., temporary identifiers) to be notified of pending DL traffic or location update. The BS does not transmit any DL traffic or paging advertisement to the MS during the mobile station's paging unavailable interval. During the paging unavailable interval, the MS may power down, scan neighbor base stations, reselect a preferred cell, conduct ranging, or perform other activities which the MS would not be available for, to any BS for DL traffic. The MS derives the start of the First Packet of Last Packet of the Session Reading Time Reading Time Reading Time The Session Positive Traffic Positive Traffic Positive Traffic Last Packet Indication In