Dynamic hybrid duplex for rate maximization in OFDMA

Orthogonal frequency division multiple access (OFDMA) is considered as one of the technologies for 4 generation (4G) due to its robustness against multi-path environment. OFDMA also has the advantage of flexibility in resource allocation, which cannot be supported by existing duplex schemes. In this paper, we propose dynamic hybrid duplex (DHD) which will enhance the efficiency and flexibility of the OFDMA system. To establish the framework of resource allocation for the DHD, we formulate DHD resource allocation problem (DRAP) which maximizes the total users’ data rate under power, rate, and subcarrier allocation constraints. A heuristic algorithm is developed to solve the problem. The algorithm finds the best mode and the best amount of resources allocated to downlink and uplink. Simulation is performed with five scenarios to evaluate the DHD. Its results show that the proposed DHD outperforms other duplex schemes in various environments.