Asymmetric decision feedback equalizer and full-duplex communication for indoor wireless applications

An asymmetric decision feedback equalizer (ADFE) and a full-duplex ADFE system are introduced. The ADFE system achieves a significant asymmetry in the distribution of computational complexity relating to equalization between two transceivers. A mean-square-error analysis is formulated to encompass both the ADFE and the decision feedback equalizer. Both equalizers are shown to have identical characterization and performance under equivalent conditions. The bit error rate of the ADFE is accurately predicted, and error-correlation results are obtained by the use of a finite discrete Markov process. The effects of timing error, adaptive training, mismatch of signal-to-noise ratio and finite precision arithmetic on the performance of the ADFE system are also examined. Transmission is in time-division duplex (TDD) format, and the access technique is time-division multiple access (TDMA). Performance and complexity comparisons are made between the ADFE and the Tomlinson-Harashima precoder with a feedforward filter (TH-FF).