Adaptive Jamming Suppression in Coherent FFH System Using Weighted Equal Gain Combining Receiver over Fading Channels with Imperfect CSI

Abstract

Fast frequency hopping (FFH) is commonly used as an antijamming communication method. In this paper, we propose efficient adaptive jamming suppression schemes for binary phase shift keying (BPSK) based coherent FFH system, namely, weighted equal gain combining (W-EGC) with the optimum and suboptimum weighting coefficient. We analyze the bit error ratio (BER) of EGC and W-EGC receivers with partial band noise jamming (PBNJ), frequency selective Rayleigh fading, and channel estimation errors. Particularly, closed-form BER expressions are presented with diversity order two. Our analysis is verified by simulations. It is shown that W-EGC receivers significantly outperform EGC. As compared to the maximum likelihood (ML) receiver in conventional noncoherent frequency shift keying (FSK) based FFH, coherent FFH/BPSK W-EGC receivers also show significant advantages in terms of BER. Moreover, W-EGC receivers greatly reduce the hostile jammers' jamming efficiency.

Performance analysis of a subset‐based coherent FFH system with spatial modulation in Rayleigh fading channels with multitone jamming

“…In our previous work [23], we proposed a novel subset‐based CFFH (S‐CFFH) scheme, which enables reliable channel estimation for CFFH over fading channels. Furthermore, we studied the BER of the S‐CFFH with maximum ratio combing [1, 23] and equal gain combining [1, 24] in the presence of partial band noise jamming, highly frequency‐selective Rayleigh fading, and imperfect channel state information (CSI). The S‐CFFH has shown higher spectral efficiency and an even better BER performance, as compared with the non‐coherent FFH schemes.…”