Multi-user UWB-OFDM communications
Ultra wideband orthogonal frequency division multiplexing (UWB-OFDM) is a novel multi-carrier UWB communication system for high bit rate wireless networks. It uses OFDM modulation with a frequency hopped pulse train in order to achieve full multipath diversity in multipath fading channels. In this paper we consider the problem of simultaneously operating piconets in the IEEE 802.15.3a WPAN standard, or multi-users in an infrastructure wireless local area network (WLAN). We propose a multi-user interference-free (MUI-free) frequency hopping multiple access scheme based on orthogonal set of Costas sequences. We also study other multiple access schemes such as orthogonal frequency division multiple access (OFDMA) and time hopping code division multiple access (TH-CDMA) for UWB-OFDM system.