ons are aligned with the MS at the boundaries of the sleep and listening windows. During the sleep window, the MS is unavailable to receive any downlink control and data trans- mission from the serving BS. The IEEE 802. 16m standard provides a framework for dynamically adjusting the duration of sleep windows. If the MS has data or signaling to transmit to the BS during the sleep window, the MS can interrupt the sleep window and request bandwidth for uplink trans- mission with or without terminating the Sleep Mode. The MS can also send or receive control/data during the listening window. The listening window is measured in units of frames. After termination of 4.1 IEEE 802. 16m mobile station state diagrams a listening window, the MS may go back to sleep for the remainder of the current sleep cycle, if there is no scheduled downlink/uplink activity. During the listening window, the BS may transmit the traffic indication message intended for one or multiple terminals. It indicates if there is traffic addressed to one or multiple mobile stations. The traffic indication message is transmitted at predefined locations. A negative traffic indication in the traffic indication message can trigger the MS to go back to Sleep Mode for the rest of the current sleep cycle. The listening window duration can be dynamically adjusted based on traffic availability or signaling in the MS or BS. In addition, the listening window can be extended to the end of the current sleep cycle. The Sleep Mode termination can be initiated either by the MS or the BS. Scanning Mode The scanning interval is a time period designated for the mobile station to monitor neighbor base stations and to determine the most suitable candidates for handover. A MAC management message may be transmitted by the MS to request a scanning interval for this purpose while in the Connected State. The scanning procedure provides an opportunity for the MS to perform neighbor-cell measurements for handover decisions. The MS may use any interval not used for communication w