Efficient scheduling algorithm for multiple mobile subscriber stations with unsolicited grant service in an IEEE 802.16e network

The IEEE 802.16e standard introduces the concept of mobile subscriber stations (MSSs) to provide mobility support. Five quality of service (QoS) classes have been defined to meet the QoS requirement of different connections between a base station and a subscriber station. Among these QoS classes, unsolicited grant service (UGS) has been designed to support real-time service flows that periodically generate fixed-size data packets. Most of the existing scheduling schemes for a UGS class consider scheduling only a single MSS; even if such schemes consider multiple MSSs, the QoS requirement of such MSSs is not appropriately satisfied after scheduling. This paper proposes a scheduling scheme, which schedules multiple MSSs with UGS connections so that the QoS requirement of each MSS can be satisfied after scheduling. The simulation results showed that the proposed approach achieved a bandwidth utilization of more than 90% and did not incur a high bandwidth waste when the number of connections was high.