Bayesian Cramer–Rao bounds for complex gain parameters estimation of slowly varying Rayleigh channel in OFDM systems

This paper deals with on-line Bayesian Cramer–Rao (BCRB) lower bound for complex gains dynamic estimation of time-varying multi-path Rayleigh channels. We propose three novel lower bounds for 4-QAM OFDM systems in case of negligible channel variation within one symbol, and assuming both channel delay and Doppler frequency related information. We derive the true BCRB for data-aided (DA) context and, two closed-form expressions for non-data-aided (NDA) context.