A Robust Coded MIMO FH-CDMA Transceiver for Mobile Ad Hoc Networks

In this paper, we develop a coded MIMO FH-CDMA transceiver that is robust to partial-band jamming and the near-far problem for ad hoc networks with high mobility. Spatial and frequency diversity are achieved respectively by differential unitary space-time modulation (DUSTM) and coding/interleaving. Decision-feedback demodulation (DFD) and erasure insertion (EI) decoding are employed to mitigate fast Rayleigh fading and interference. A decision-directed adaptive estimator is also developed to estimate the required parameters in DFD and EI. The two proposed EI schemes are based on the Bayesian framework proposed by Baum and Pursley (1992) and a novel threshold test of the effective signal to noise and interference ratio (ESINR), respectively. Decoding error probability of the ESINR based EI is derived analytically. Performance of both EI schemes are examined under various interference conditions, and the effect of EI thresholds is carefully discussed. The Bayesian EI is shown to be insensitive to suboptimal threshold and achieves significantly better performance than error-only decoding. Furthermore, it is shown that analysis of the ESINR based EI scheme predicts the performance of the Bayesian EI when the interference is dominant.