Uplink resource allocation in OFDMA relay-assisted cellular network with fairness

Uplink subcarrier and power allocation is studied for OFDMA relay-assisted cellular network. Assuming that the base station has all the channel state information (CSI), an optimization problem for an adaptive subcarrier and power allocation scheme that maximizes system capacity while guaranteeing minimum resources for each user with constraint of overall transmission power is formulated. Since the optimal solution is computationally complex to obtain, a two-step suboptimal approach is proposed. The subcarrier allocation in the first step based on the equivalent channel- noise-ratio can exploit multiuser diversity as much as possible while impose certain fairness among users. In the second step power distribution methods with spacail water-filling and MS-based water-filling are proposed to maximize capacity of predetermined subcarrier assignment. Numerical results show that the proposed solution can achieve significant improvement on system capacity while guarantee minimum fairness among users.