Capacity optimization of a 802.16e OFDMA/TDD cellular system using the joint allocation of sub-channel and transmit power

This paper solves the problem of finding a suitable sub-channel and power joint allocation method for multiple users in 802.16e OFDMA/TDD cellular systems. The joint allocation is that firstly the sub-channel is allocated to the users and then suitable power is allocated. We propose a FASA (Fairness insured Aggressive Sub-channel Allocation) algorithm which is a dynamic channel allocation algorithm considering all users' channel state information conditionally to maximize fairness and throughput. We compare the FASA algorithm with the conventional algorithms in the 2-tier cell environment and then analyze the performance of each algorithm through computer simulation in the downlink of 802.16e OFDMA/TDD system. The improved CHC algorithm, which is dynamic power allocation algorithm, is also proposed in this paper. The Improved CHC algorithm collects the extra of the downlink transmit power and then re-allocates it to other users. Simulation results show that the proposed improved CHC algorithm additionally increases the fairness and sector throughput.