UWB Narrowband Interference Survey and Design Considerations

A study of interference caused by incumbent radios to UWB devices is presented. Through an extensive set of measured spectral activities in the low-band IEEE802.15.4 UWB operating channels, we explore the outage probabilities of a UWB system when it is equipped with an intelligent detector for combating interferers and compare them against those of a naive system that has no interference avoidance capability. Our results reveal that a UWB system with an effective interference avoidance capability may lead to a few orders of magnitude improvement in its outage probabilities. The measured outage probabilities are confirmed through measuring the frame error rate of a simulated filter-bank UWB transceiver system when impacted by the interferences obtained through our experiments.

Filter-Banks for Ultra-Wideband Communications: Advantages and Design Challenges

Recently, filter-bank multicarrier spread spectrum (FBMC-SS) has been proposed as a candidate waveform for ultra-wideband (UWB) communications. It has been noted that FBMC-SS is a perfect match to this application, leading to a trivial method of matching to the required spectral mask at different regions of the world. FBMC-SS also allows easy rejection of high-power interfering signals that may appear over different parts of the UWB spectral band. In this paper, we concentrate on the use of staggered multitone spread spectrum (SMT-SS) for UWB communications. SMT makes use of offset quadrature amplitude modulation (OQAM) to transmit data symbols over narrowband, overlapping subcarrier bands. This form of FBMC-SS is well-suited to UWB communications because it has good spectral efficiency and a flat power spectral density (PSD), resulting in good utilization of the UWB spectral mask. Additionally, we explore new methods for multi-coding that result in higher bit rates than previous FBMC-SS systems. Moreover, we study methods for equalizing the UWB multipath channel and cancelling narrowband interference. Excellent performance of the proposed methods are substantiated by presenting simulation results.