Joint energy saving resource allocation and user scheduling in OFDMA relay networks

Joint energy saving resource allocation and user scheduling scheme in orthogonal frequency division multiple access (OFDMA) relay networks is considered. Different from allocating resources for users, we allocate resources for packets in the priority queue. Before resource allocation, a scheduling scheme is carried out to assign different priorities to the packets in the queue to guarantee the fairness and better system throughput. The energy minimization resource allocation problem is formulated in OFDMA relay networks, in which time domain, sub-carriers, bit and power resources are dynamically allocated. Instead of adopting two transmission phases of equal size in time domain in most of existing proposals, time domain resource is allocated dynamically in this paper. The integer programming is adopted to obtain the solution based on the discrete variables. However, owing to the high algorithm complexity of integer programming, an efficient algorithm is proposed based on decomposing the original optimization problem into three subproblems. Simulation results show that the energy consumption of proposed scheme is quite close to that of optimal algorithm. Because the proposed resource allocation algorithm is based on the packets queue, we also propose a novel user scheduling scheme, which considers the relay selection results and the service types. Simulation results show that the system throughput of proposed scheduling scheme is larger than that of PF, while its fairness index is close to that of PF.