Capacity and throughput for transmission over flat fading channels employing SNR-priority-based channel allocation scheme

Abstract

An adaptive SNR-priority-based channel allocation scheme over multiple access fading channel is proposed. The performance of this scheme is a compromise between the conventional TDMA scheme which has short channel access waiting time but poor spectral efficiency, and the best SNR user transmitting scheme which has better bandwidth efficiency but longer channel access waiting time. The capacity achieved by this scheme is studied and compared with the conventional rate adaptive TDMA systems. The operation of this scheme requires channel estimation which is performed at the frame period for all N mobiles. For the SNR-priority -based system, the frame period is divided into K slots and only K mobiles that observe the first K best channel conditions are assigned to transmit. By assuming that only best-effort traffic is served, the channel capacity and the system throughput of the SNR-priority-based TDMA system achieved with rate adaptive MQAM modulation technique are studied. The average channel inter-access time for such a system is also studied through simulation.