For high data rate ultra wideband communication system, performance comparison of Rake, MMSE and RakeMMSE receivers is attempted in this paper. The effect of the number of Rake fingers and equalizer taps on the error performance by combating ISI are the major focus of our research. The bit error rate performances are investigated using semi analytical approach and Monte-Carlo simulation on IEEE 802.15.3a UWB channel models. Simulation results show that the bit error rate probability of rake-mmse receiver is better than individual Rake and MMSE receiver. The simulation results are illustrated using non-line of sight indoor wireless channel model (CM3 and CM4). It was observed that RAKE-MMSE receiver structure gives superior performance in CM3 channel model with small delay spread compared to CM4 channel model.