A Low Complexity Simulation Algorithm for TH-UWB MMSE RAKE Receiver in NLOS Channel

In this work, we implement a MMSE RAKE receiver for ultra-wideband (UWB) system in a presence of a reach multipath environment, using an enhanced time-hopping system simulator. It is known that MMSE receiver has the best performance in terms of signal-to-noise-plus-interference-ratio (SINR) at the expense of high computational complexity. In addition, in order to process ultra-wideband signals, an extremely large sampling rate is mandatory. Therefore, in order to compute bit error rate (BER) curves, simulation time can be very long. Since the transmitted waveform is "hidden" in transmitted-distorted-received waveform (TDR), as it will be shown in this work, a typical multiuser structure does not exist and the implementation of any multiuser detector in this algorithm might be a difficult issue. Therefore, applying this method, it is not necessary to operate with a signal sample in every simulation and it is possible to reduce the simulation process significantly. This algorithm takes advantage of some of the properties of time-hopping ultra-wideband (TH-UWB) systems in order to improve all the previous designs by several orders of magnitude, independently of the sampling rate, in terms of a very straightforward and fast processing. Additionally, we derived a theoretical formula of the performance of the MMSE detector for PPM IR-TH-UWB based on this new approach.