Abstract:

 Allocation mechanisms of spreading-spectrum rate in wireless networks with low signal-to-noise ratio due to strong interference are investigated for the purpose of ensuring relatively reliable communications. Based on DS-TDMA(Direct Spreading-Time  Division Multiple Access), a novel ASMAC（Adaptive Spreading Multiple Access Control）protocol, is present on the basis of adaptive frequency-spreading techniques, whose major innovation lies in that each mobile terminal is configured to piggyback its current SNR(Signal-to-Noise Ratio) and its expected traffic rate with its access request to the BS(Base Station). Before the beginning of each frame, BS will consider the overall requirements from different mobile terminals and allocate spreading-spectrum rate among them according to specially designed policy. Simulation results show that this algorithm is capable of providing an average connection rate of 8.6% even under an environment with -12 dB SNR.

Key words: signal-to-noise ratio(SNR), spread-spectrum ratio, multiple access control (MAC)