Throughput performance of M-ary/SSMA slotted Aloha systems

An M-ary/spread spectrum multiple access (M-ary/SSMA) system can achieve higher data transmission rate and can improve the bit error rate under additive white Gaussian noise (AWGN). In this paper, the M-ary/SSMA slotted Aloha system, which combines the spread Aloha system with the M-ary/SSMA system, is discussed. In particular, the throughput performance in the presence of AWGN and Rayleigh fading is analyzed. Moreover, the M-ary/SSMA slotted Aloha systems are compared with the conventional direct-sequence/spread spectrum multiple access (DS/SSMA) slotted Aloha systems. Consequently, it is found that the maximum throughput of the M-ary/SSMA slotted Aloha system is higher than that-of the conventional DS/SSMA slotted Aloha system.