Analysis of the Impact of WiMAX-OFDM Interference on Multiband OFDM

Abstract

This paper presents an analysis of the performance of the multiband orthogonal frequency division multiplexing (MB-OFDM) system for ultra wideband (UWB) communication in the presence of interference from an IEEE 802.16 WiMAX-OFDM system operating in the 3.5 GHz band. Recent work (Hu & Beaulieu, IEEE Trans. Commun., Oct. 2006) has demonstrated accurate Gaussian approximations for narrowband OFDM interference to time-hopping and direct-sequence UWB victim receivers, but little analysis has been done for MB-OFDM. Because of the significant differences in signal model and receiver design, it is also not clear that such Gaussian approximations hold for MB-OFDM victim receivers. Motivated by this question, we present an exact analysis of the uncoded bit error rate (BER) of the MB-OFDM system, based on Laplace transform techniques. We also present a simple but accurate Gaussian approximation for the WiMAX-OFDM interference, and confirm both the exact and approximate analysis via simulations. We find that, depending on the signal-to-interference ratio, interference from WiMAX-OFDM systems may have a substantial impact on the performance of MB-OFDM. However, the approximately Gaussian nature of the interference signal gives hope for the development of simple interference detection and mitigation techniques.