Code-multiplexed transmitted-reference UWB systems in a multi-user environment

Recent studies have investigated alternative methods to the realization of transmitted-reference ultra-wideband communication systems. In addition to the conventional scheme, in which data and reference are separated in time, two other methods have been proposed in which the separation is achieved through a frequency shift or via code multiplexing. In a single-user scenario the alternative methods have advantages in terms of error rate and receiver implementation. In this paper the three schemes are compared in a multi-user environment. It is shown that even in the presence of multiple access interference the unconventional solutions are preferable and, in particular, the code multiplexing method has the best performance and is the simplest to implement.