Study of UGS grant synchronization for 802.16

IEEE 802.16 defines UGS (unsolicited granted service) to support real-time service flows that generate fixed size data packets periodically. It offers fixed size unsolicited data grants on a real-time periodic basis to meet the periodic transmission requirements. However, the synchronization mismatch between these two periodic behaviours may lead to a possible delay. To combat this delay, a form of grant synchronization mechanism must be employed for UGS. In this paper, grant synchronization for 802.16 is studied. Some mechanisms are given to reduce the delay derived from synchronization mismatch. At the same time, the jitter introduced from these mechanisms is also taken into consideration. NS2 (network simulator) is used to simulate the performance of these mechanisms and a conclusion is derived based on the simulation result.