Optimization of Downlink Bandwidth Allocation for Energy Efficiency over OFDMA Wireless Networks

For the multicast channel assignment issue with multi-layer, this paper studies a resource allocation problem for minimizing the energy consumption of subscriber stations in Orthogonal Frequency Division Multiplexing Access (OFDMA) wireless systems. Not only does the requirement have to be guaranteed when multicast users receive video content in layer-based video coding, but also the energy consumption needs to be minimized. In this paper, the energy consumption of each station is optimized by minimizing the number of active symbols. The scheduling process is divided into two phases. First, the number of requested tiles is minimized by proposed scheme Layer Determination Scheme with SVC (LDS) for the issue of optimizing energy consumption. The proposed LDS scheme determines the modulation of the selected layer and assigns available tiles to the selected layer. In the secondary phase, the symbol scheduling problem is minimizing the number of active symbols for each station. The Complementary Matching Algorithm (CMA) is proposed to minimize the total number of active symbols in an OFDMA wireless system. The problems of symbol scheduling are reduced to the subset sum optimization problem to find the complementary subset of a request. In the simulation results for the proposed LDS and CMA algorithms, we found that the solutions generated by our algortihms have better performance in terms of energy consumption and throughput.