TDMA scheme has an intrinsic problem that cannot allocate optimal length of timeslot to each station for burst traffic services, which would waste lots of timeslots especially in the multi-frame TDMA systems that send multiple frames within one timeslot. If the base station detects the existence of idle timeslot, it could inform other stations of the occurrence of idle timeslot so that the idle timeslot can be reused by other stations. Using this proposed scheme, the stations can efficiently utilize timeslots without loss even through the burst traffic environments.
However, there are significant overheads for reusing idle timeslot explicitly. In order to reduce the reuse overheads, I propose a new hybrid multiple access scheme based on both TDMA and CSMA. A TDM timeslot virtually allocated for a specific station can be accessed by other stations using CSMA.
Through the ns-2 simulations, we quantify the performance of the idle timeslot reusing scheme in both environments of real-time multimedia traffic and high data rate traffic. To verify throughput gain of proposed protocol, I used bulk server queueing system for modeling the multi-frame TDMA and calculated throughput gain by deriving simple probability function. Through the comparison between numerical analysis and NS-2 simulation, we can make the similar results for the normalized throughput.
