Energy-efficient resource allocation for multiple description coding based multicast services in OFDMA networks

摘要

Multicast is a promising technique for mobile network operators to efficiently launch media services. With its standardization in LTE networks, LTE multicast has attracted growing attention from industry recently. In this paper, we investigate the energy-efficient resource allocation for multicast services in orthogonal frequency division multiple access (OFD-MA) networks. Multiple description coding (MDC) technique is adopted to exploit multichannel diversity and multiuser diversity, which can eliminate the intrinsic inefficiencies of the multicast rate constraint. For the MDC based multicast services, we formulate a joint subcarrier assignment and power allocation problem to maximize the system energy efficiency under power constraints. To handle the fractional combinatorial optimization problem, we transform the problem into a subtractive form and then solve it using a Dinkelbach-based optimal algorithm, which requires full search of all possible user activation patterns. To reduce the complexity, we further propose a heuristic algorithm by separating user activation and power allocation for the original problem. Numerical results demonstrate the effectiveness of the proposed algorithms and validate the tradeoff between the energy efficiency and the spectral efficiency.