Erasure insertion for coded MIMO slow frequency-hopping systems in presence of PBI

We investigate two erasure insertion schemes for a coded slow frequency-hopping system with multiple antennas at both the transmitter and the receiver. The demodulated symbols may become unreliable due to fading, thermal noise, and partial band interference (PBI). Since error correcting codes can correct more erasures than errors, it is often beneficial to erase these unreliable symbols rather than feeding them to the decoder. In this paper, we first extend the Bayesian erasure insertion, originally proposed in C.W. Baum and M.B. Pursley (1992) for FSK modulation, to the case when differential space-time modulation is used. We then propose a simple, suboptimal erasure insertion scheme based on a likelihood ratio threshold test (LRTT). Simulation results show that substantial improvements in decoding error probability can be achieved by the proposed schemes over the non-erasure-insertion scheme, especially when the partial-band interference becomes severe