Resource Allocation for Guaranteed Service in OFDMA Based Systems

Orthogonal frequency division multiple access (OFDMA) is the access technique adopted in the new generation wireless networks such as WiMAX. In this paper, we consider resource allocation of OFDMA in time division duplex (TDD) mode in which the new transmission frame with multiple time slots is popped up on every pre-specified period. Frame resource is divided into chunks that are composed of a group of subcarriers with equal and constant time duration. Our centralized resource allocation scheme aims to provide the guaranteed service to users by converting the required service into the network cost. The users whose network costs are too high are not guaranteed in order not to waste the precious bandwidth. We formulate the optimization problem with the objective of minimizing the total cost. Furthermore, a heuristic method is proposed to schedule users´ data into the downlink subframe by exploiting multiuser multichannel diversity to guarantee the service and to utilize system´s bandwidth wisely. Intensive simulation shows that our scheme provides satisfied throughput, low packet drop rate, and low queuing delay. Moreover, the results also show that the scheme is fair to users in both throughput and service time.