Random Sign Repetition Time-Hopping UWB with Multiuser Detection

Recently, ultra-wideband (UWB) technology, which uses a very short pulse for wireless digital communications, has been extensively investigated due to its significance that enables to transmit data sequences at a very high rate. Although the propagation range of UWB signals is short (about ten meters [1]), its impact on wireless home networks can be quite significant. Apart from the support of a high data rate, UWB can also provide multiple access so that multiple transmitters can be active simultaneously [2] and construct wireless networks [3]. A conventional UWB uses time-hopping (TH) sequences for multiple access and pulse-position modulation (PPM) for signaling [2]. There are other variations of UWB. In [4], an UWB based on direct sequence spreading has been considered and compared to the conventional TH-UWB. Due to the cochannel interference from other UWB transmitters, the performance is generally limited by the cochannel interference. In [5, 6], a characterization of the cochannel interference and performance analysis for the conventional TH-UWB are discussed. Since UWB systems suffer from the cochannel interference as code-division multiple-access (CDMA) systems, it would be possible to apply some interference suppression methods in CDMA to UWB. In [7], the multiuser detection for UWB that employs CDMA signaling is discussed. In [8], the multiuser detection for the conventional TH-UWB is investigated.