PERFORMANCE EVALUATION OF NBI SUPPRESSION IN UWB-IR SYSTEM USING MMSE-RAKE RECEIVER

Abstract

Ultra Wideband Technology for commercial communication application is a recent innovation. Short-range wireless systems have recently gained a lot of attention to provide multimedia communications and to run high speed applications around a user centric concept in so called Wireless Personal Area Networks (WPAN). UWB technology presents itself as a good candidate for the physical layer of the WPAN. In February 2002, the FCC issued a ruling that ultra-wideband (UWB) could be used for data communications as well as for radar and safety applications. UWB system is constrained to have a maximum power transmission of -41 dBm and a bandwidth ranging from 3.1-10.6 GHz. UWB co-exists and does not interfere with the existing narrowband or wideband communication systems in the same spectrum. However, due to its low power in the same bandwidth, UWB is affected by the so-called narrowband interference (NBI). This report presents a method to eliminate the narrowband interference in UWB system. The TH-UWB system performance was analyzed in a realistic UWB frequency selective channel and in the presence of NBI for RAKE receiver. We demonstrated that TH reduces the impact of multiuser interference but does not combat NBI. To suppress NBI, a Partial Rake receiver used. It consists of selecting the first strongest multipath components using an appropriate Rake receiver with the path diversity combining being based on the minimum mean square error criterion. The design correctness has been validated by means of simulation using standard UWB IEEE standard channel models, Time Hopping-Pulse Position Modulation and the rake receiver technique with the path diversity combining being based on the minimum mean square error criterion.