New UWB Receiver Designs with Improved Performance in Multiple Access Interference

Ultra-wide bandwidth technology (UWB) is proving to be a promising solution for high capacity, wireless multiple access systems. Described as Bluetooth on steroids, UWB provides extremely high data rate performance in multiple user applications. It will replace wires and cabling in commercial, industrial, educational and residential applications. In local and personal area networks (LAN/PAN), UWB will connect cellphones, laptops, PDAs, cameras and MP3 players. In the automotive space, UWB can be integrated with in-car service and entertainment as well as roadside info-stations. UWB will make collision avoidance-detection available to private motorists and heavy equipment operators.

Meanwhile it has been shown that multiple access interference (MAI) significantly degrades the performance in these systems, and the widely adopted correlation receiver is not an optimal receiver structure for MAI in both time-hopping (TH) and direct sequence (DS) UWB systems. Researchers at the University of Alberta have developed a number of approaches to optimize receiver detectors, based on better statistical models for the MAI. The new receivers for TH-UWB outperform the correlation receiver in the following environments:

• for MAI plus Gaussian noise environments: the `soft-limiting` receiver, ref. 2005-072. For further information, see Beaulieu & Hu, ""An adaptive threshold soft-limiting UWB receiver with improved performance in multiuser interference"", in Proc. Int. Conf. Ultra-Wideband, Sept. 2006.
• for mixed MAI plus Gaussian noise environments: the `zonal` receiver, ref. 2006053, and the `p-omr` using an adaptive threshold, ref. 2006-054. The receivers also outperform the soft-limiting receiver at large SNR values (zonal) and for all SNR and SIR values (p-omr). To be presented at Globecom, November 2007.
• for a mixture of Laplace and Gaussian noise: ref. 2006052. The receiver also outperforms the soft-limiting receiver for small values of SNR. For further information, see Beaulieu and Niranjayan, ""New UWB receiver designs based on a Gaussian-Laplacian noise-plus-MAI model"", IEEE Int.Conf.Comm. Glasgow, June 2007.

• Improved reliability and bit error rate performance
• Increased coverage and reliability under all operating conditions in interference
• Increased user capacity is supported by the new receiver designs