Sleep scheduling in IEEE 802.16j relay networks

Power saving for mobile stations (MSs) is one of the most critical issues in IEEE 802.16j relay networks. To reduce power consumption of MSs, IEEE 802.16j borrows the sleep mode of 802.16e, but new parameters are introduced. Up to now, no previous work has addressed the sleep scheduling problem in IEEE 802.16j networks. Therefore, this paper proposes an energy-efficient, standard-compliant sleep scheduling scheme which involves relay stations (RSs) and realizes spatial reuse on RS transmissions to minimize energy consumption of MSs while guaranteeing their QoS. The main idea of the proposed scheme is to interleave the sleep patterns of MSs and exploit spatial reuse on MS-RS transmissions to reduce resource consumption while enlarging the available frame space. Comprehensive simulation has been conducted to verify the effeteness of our scheduling scheme. It shows that our scheme can serve more requests of MSs while increasing their sleep ratios.