Efficient and adaptive resource scheduling in IEEE 802.16j transparent relay networks

Relaying is regarded as a promising technique for enhancing the system throughput and coverage of emerging broadband wireless access networks. While next generation broadband wireless standardization bodies (e.g., LTE-advanced and IEEE 802.16j) have specified the support of relays in general terms, the problem of allocating network resources in an efficient and effective manner remains a challenging issue. In this study, the utility-based resource scheduling optimization problem for IEEE 802.16j transparent relay networks is formulated mathematically and proven to be NP-hard. Two efficient heuristic algorithms, namely Relay Resource Scheduling (RRS) and Adaptive Relay Resource Scheduling (ARRS), are proposed to resolve the resource scheduling problem. RRS maximizes the system utility in networks containing direct and relay mobile stations by exploiting the benefits of optional transmissions. ARRS enhances upon the performance of RRS by adaptively determining the split ratio between the access zone and the transparent zone in the downlink subframe. The computational complexities of both algorithms are shown to be polynomial and proportional to the number of links and subchannels in the network. The simulation results show that the proposed algorithms achieve significantly better throughput and fairness performance than existing schemes such as Partial Proportional Fairness (PPF) and GenArgMAX.