A Robust Decoding Method for OFDM Systems Under Multiple Co-Channel Narrowband Interferers

摘要

Software Defined Radio platforms are theoretically capable of operating more than one wireless standard simultaneously. The significant challenges arise when the operating standards use overlapping frequency bands. Co-channel interference (CCI) is one of such challenges which have been in focus of the cellular communication community, but not in the Industrial, Scientific and Medical (ISM) radio bands where multiple heterogeneous wireless standards operate without a centralized coordination. Recognizing Successive Interference Cancellation (SIC) as one of the proven mechanisms to mitigate CCI, we propose methods to improve Packet Error Rate (PER) of wideband OFDM-based systems in the presence of multiple cochannel narrowband interferers. Our methods achieve improvements in PER statistics at lower received power level compared to conventional methods. Reduction in PER of the dominant OFDM signal makes more packets available for regeneration and hence cancellation during SIC procedure which aides the decoding of weaker signal. We also propose a simple yet efficient method to detect the presence and positioning of multiple narrowband interferers. Extensive Monte-Carlo simulations show that our methods elevate a receiver sensitivity gain up to 6 dB and are capable of detecting multiple narrowband interferers simultaneously. Our methods require modifications in the physical layer of the receiver only and hence can be integrated into existing infrastructure.