Throughput analysis of DS CDMA/unslotted ALOHA wireless networks with fixed packet length in rayleigh fading finite-state markov channel model

We propose the finite-state Markov channel (FSMC) model to the throughput analysis of DS CDMA/unslotted ALOHA wireless networks in the mobile environment. The FSMC model can characterize the correlation structure of Rayleigh fading process, and the degree of correlation depends on the Doppler frequency shift. The FSMC model is suited to the throughput analysis by queueing theory due to its Markov chain nature. The previous papers in DS CDMA/unslotted ALOHA wireless networks in Rayleigh fading consider a whole packet. They ignore that the channel gain or multiple access interference can change symbol-to-symbol. In our proposed analysis, both the channel gain and multiple access interference can change from symbol to symbol. It is not just a packet-level analysis in the previous papers, and is a more general symbol-level analysis. Our generalized scheme should be more suited to realistic Rayleigh fading in the mobile environment. We consider two cases: (1) the system without carrier load sensing protocol (CLSP) and (2) systems with CLSP. For both cases, we analyze the theoretical throughput by queueing theory for various averaged signal-to-noise ratios and Doppler frequency shifts, and the computer simulated throughput matches the theoretical throughput.