Information efficiency and transmission range optimization for coded MIMO FH-CDMA Ad Hoc networks in time-varying environments

Optimization of the transmission range in terms of maximizing information efficiency is studied in this paper for mobile ad hoc networks (MANETs) 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 due to mobility and hopping. The receiver employs decision-feedback demodulation for differential unitary space-time modulation and erasure insertion decoding for Reed-Solomon codes [14] [15]. The decoding error probability is derived based on distributions of the multiple access interference power and the signal-to-interference ratio in a dwell for ground propagation model. The trade-off between information efficiency and transmission range is studied in detail and insight is obtained into the impact of various factors, including the spreading gain, modulation and coding schemes, feedback length, erasure insertion, order of spatial diversity, time-variation of the shadowing, and channel statistics such as Doppler frequency and shadowing spread.