Pilot Assisted SNR Estimation in a Non-Coherent M-FSK Receiver With a Carrier Frequency Offset
Pilot-assisted estimation of Signal-to-Noise Ratio (SNR) is considered for an orthogonal non-coherent M-ary FSK receiver having a Carrier Frequency Offset (CFO) at the front end. The received signal is also corrupted by symbol-rate Rayleigh fading and additive white Gaussian noise. A two-step estimation procedure is designed by observing received data in the receiver. In the first step, an asymptotically unbiased estimate of CFO is obtained using a moments based approach. This estimate is then used to derive a maximum-likelihood estimator for the SNR. The Cramer Rao Bound for SNR has been derived to compare the overall estimator performance in terms of its variance.