Transmission Range Optimization for FH-CDMA Networks in Time-Varying Channels

Optimization of the transmission range for maximizing information efficiency is studied in this paper for mobile ad hoc networks with frequency-hopped (FH) CDMA and multiple antennas. Realistic channel models are employed to account for path-loss, log-normal shadowing, and Rayleigh fading. The shadowing and fading are assumed time-varying with different time-scales. The receiver performs decision-feedback demodulation for differential unitary space-time modulation and erasure insertion decoding for Reed-Solomon codes. The decoding error probability is derived based on distributions of the multiple access interference power and the SIR for ground propagation model (path-loss exponent equal to 4). The trade-off between information efficiency and transmission range is studied in detail and insight is obtained into the impact of various system parameters.