On the Detection Methods for Indoor Ultra Wideband Communications with Multiple User Interference

In high data rate indoor ultra wideband (UWB) communication systems, the selection of the appropriate detection method in the receiver is always an important problem. This paper compares the performances of two different detection methods, hard decision detection (HDD) and soft decision detection (SDD), for three different types of indoor UWB systems named time hopping pulse position modulation (TH-PPM), direct sequence bi-phase modulation (DS-BPM) and time hopping bi-phase modulation (TH-BPM) UWB indoor communication systems with multiple user interference (MUI). Using the recently accepted IEEE 802.15.3a UWB channel model, the three schemes were compared. Finally, it has been concluded that for both DS-BPM and TH-BPM systems, SDD outperforms HDD in terms of BER performance and so SDD should be chosen as the preferred detection scheme. However, in case of TH-PPM system, the system BER performance depends on the pulse repetition rate, any of SDD and HDD can be chosen as preferred detection scheme if one pulse per bit is used whereas for multiple pulses per bit SDD outperforms HDD significantly. Using SDD method, DS-BPM scheme can achieve the maximum SNR gain in presence of multiple user interference (MUI)