Transmit-reference (TR) schemes are commonly used only in low data rate ultra-wideband (UWB) systems because of many restrictions on the pulse spacing, frame and symbol periods (should be longer than the channel length). This paper extends our previous research that tries to remove these restrictions to enable a higher data rate application in a multiuser context. Based on the fact that most UWB channels are highly uncorrelated, we can formulate a CMDA-like signal processing model for an asynchronous multiuser system. Blind and iterative algorithms are derived, of which the performances are compared and verified in simulations.

Transmit-reference ultra-wideband (TR-UWB) systems are attractive due to their relatively low complexity at both the transmitter and the receiver. Partly, this is achieved by making restrictive assumptions such as a frame length which should be much larger than the channel length. This limits their use to low data rate applications. In this paper, we lift this restriction and allow inter-frame interference FI) to occur. We propose a suitable signal processing data model and corresponding receiver algorithms which take the IFI into account. The performance of the algorithms are verified using simulations.

A communication system based on transmit-reference (TR) ultra-wideband (UWB) is studied and further developed. Introduced by Hoctor and Tomlinson, the aim of the TR-UWB transceiver is to provide a straightforward impulse radio system, feasible to implement with current technology, and to achieve either high data rate transmissions at short distances or low data rate transmissions in typical office or industrial environments. The main contribution in this paper is the derivation of a signal processing model that takes into account the effects of the radio propagation channel, in particular, for the case where the two pulses in a doublet are closely spaced. Several receivers based on the code-division multiple-access-like properties of the proposed model are derived, and the performance of the algorithms is tested in a simulation.

The delay-hopped transmit-reference ultra wideband communication system introduced by R. Hoctor and H. Tomlinson (see IEEE Conf. Ultra Wideband Systems and Technologies, p.93-8, p.265-70, 2002) results in a receiver based on a bank of correlators and a sliding window integrator. We derive a complete signal processing model for this receiver structure. In particular, we take the effects of the radio propagation channel on the correlations into account, as well as the effects of the additive noise. Blind and semi-blind receiver algorithms are proposed to estimate the effective channel coefficients and the data; the performance of the algorithms is tested in simulations.