This paper considers a broadband cellular orthogonal frequency division multiple access (OFDMA) system with relay nodes operating in decode-and-forward (DF) mode. An optimization problem for relay selection, subcarrier assignment and power allocation that maximizes the downlink capacity with fairness consideration among users is formulated for such a system. Since the problem cannot be solved easily in direct forms, we make continuous relaxation and solve the dual problem of the relaxed problem using a subgradient method. An integer-valued solution is then obtained from the result of the subgradient method. Numerical results show that our proposed algorithm solves the problem with superior capacity performance and low outage probability.
['Zhihua Tang', 'Guo Wei']
Resource Allocation with Fairness Consideration in OFDMA-Based Relay Networks