Signal detection based on log-likelihood ratio in OFDM systems with frequency offset

In this paper, we propose new signal detection schemes for orthogonal frequency division multiplexing (OFDM) systems with carrier frequency offset over slowly-varying frequency-selective fading channels. The main idea is to detect a block error based on cyclic redundancy code (CRC) and to correct an error based on ordering the magnitude of log-likelihood ratio (LLR). It is shown that the proposed LLR-based detection scheme is more efficient than the conventional ing scheme and the minimum mean squared error (MMSE) scheme in terms of computational complexity and bit error rate (BER) performance.