Relay Selection and Resource Allocation for Multi-User Cooperative OFDMA Networks

The resource allocation problem is investigated for relay-based multi-user cooperative Orthogonal Frequency Division Multiple Access (OFDMA) uplink system, considering heterogeneous services. A quality of service (QoS) aware optimal relay selection, power allocation and subcarrier assignment scheme under a total power constraint is proposed. The relay selection, power allocation and subcarrier assignment problem is formulated as a joint optimization problem with the objective of maximizing the system throughput, which is solved by means of a two level dual decomposition and subgradient method. To further reduce the computational cost, two low-complexity suboptimal schemes are also proposed. The performance of the proposed schemes is demonstrated through computer simulations based on LTE-A network. Numerical results show that the proposed schemes support heterogeneous services while guaranteeing each user´s QoS requirements with slight total system throughput degradation.