p Mode MOB_SLP- Encrypted/ICV Unicast Sleep Response BS to the MS in response to Operation an AAI_SLP-REQ message. The BS may send this message in an unsolicited manner. If the request is rejected by the BS, the MS will not retransmit the AAI_SLP-REQ message before a certain time interval signaled in the AAI_SLP-RSP message elapses. AAI_TRF-IND This message is sent by the Sleep Mode MOB_TRF- Broadcast Traffic Indication BS to the mobile stations in Operation the first frame of mobile station's listening window. (Continued) Table 6-8 IEEE 802. .16m MAC Management/Control Messages [1,2] Continued 802.16- IEEE 802.16m Standard MAC Management Message Equivalent Security Message Description Connection Usage Message Attributes The mobile stations that have not been assigned SLPID would ignore this message. This message indicates whether there is DL traffic for mobile stations that are explicitly addressed. There are two formats for the AAI_TRF-IND message, as indicated by the format field of the message. If the MS does not find a SLPID-Group Indication bitmap or a Traffic Indication bitmap, the MS considers it as a negative indication and may go back to sleep. If the MS does not find its own SLPID in the AAI_TRF- IND message, the MS considers it as a negative indication and may go back to sleep. AAI_TRF_IND-REQ If the Traffic Indication Sleep Mode Traffic Indication MOB_TRF- Encrypted/ICV Message Flag is set to 1, the Unicast Operation Request MS receives an AAI_TRF-IND message in the first frame during the listening window; otherwise, the MS stays awake for the rest of the listening window. If the MS receives any unicast data during the listening window, then it assumes that the Traffic Indication Message Flag was set. If the MS receives neither the Traffic Indication Message Flag nor any other unicast data in the listening window, the MS would send an AAI_TRF_IND- REQ message to the BS in order to inquire about the status of Traffic Indication Message Flag. The BS will respond to the MS by sending an AAI_TRF_IND-RSP 