New implementations of the time-reversed precoders for UWB communication system

Ultra-wideband communications system with pre-coders based on time-reverse channel impulse response have been shown to yield improved bit error rate performance for a given signal to noise ratio. However, as the channel impulse response is usually quite long, the implementation of the full time-reversed precoders involves high implementation complexity. We propose two implementation methods that will reduce the implementation complexity. In the first method, representation of the impulse response by fewer number of bits such as 1, 2, 4 and 6 is considered. In the next method, the channel impulse response is modeled using autoregressive moving average model obtained using Prony method. Two implementations, namely time reversed Prony precoder model and data reversed Prony precoder model, are investigated. The performances of the communication system for various channel models CM1, CM2, CM3 and CM4, as presented in IEEE 802.15.3a, with different precoder models were obtained using simulation. It was observed that data reversal based implementation of Prony model precoder was able to produce the same level of Bit Error Rate (BER) performance with reduced implementation complexity compared to non-recursive implementation. The simulation results for the various cases of the partial precoders are presented.