Decision feedback channel estimation without prior knowledge of terminal mobility for SC-FDE

An adaptive decision feedback channel estimation (DFCE) scheme using likelihood value comparisons in single-carrier frequencydomain equalization (SC-FDE) is presented here. Previously, we proposed a DFCE scheme for SC-FDE that realizes adaptive tracking of the channel variations with prior knowledge of the terminal mobilities obtained from moving speed information. However, the adaptive tracking method requires determination of an appropriate forgetting factor of the DFCE using the terminal speed information at the receiver. Thus, in this study, we adaptively control an appropriate forgetting factor that corresponds with the channel variations of the DFCE scheme without prior knowledge of the terminal speed. The novelty of the proposed approach is that the likelihood values for different forgetting factors are calculated from the forward error correction (FEC) decoding results, and the appropriate forgetting factor is then chosen by comparing the likelihood values to adjust to either noise-dominant or time-selectivity-dominant channel. The effectiveness of the proposed scheme is further demonstrated via computer simulations by comparisons with the traditional DFCE using the terminal speed information.