Code-Multiplexing-Based One-Way Detect-and-Forward Relaying Schemes for Multiuser UWB MIMO Systems

In this paper, we consider decode-and-forward (DF) one-way relaying schemes for multiuser impulse-radio ultrawideband (UWB) communications. We assume low-complexity terminals with limited processing capabilities and a central transceiver unit (i.e., the relay) with a higher computational capacity. All nodes have a single antenna differently from the relay in which multiple antennas may be installed. In order to keep the complexity as low as possible, we concentrate on noncoherent transceiver architectures based on multiuser code-multiplexing transmitted-reference schemes. We propose various relaying systems with different computational complexity and different levels of required channel knowledge. The proposed schemes largely outperform systems without relay in terms of both bit error rate (BER) performance and coverage

A Differential Receiver for UWB Systems

We consider a UWB communication system operating in a typical indoor environment and we propose a novel differential receiver in which encoding is performed symbol-by-symbol rather than frame-by-frame, as is normally done. The detector structure is derived in a single-user scenario using a generalized likelihood ratio test approach. Its performance is assessed by simulation in the presence of multiple-access interference. The proposed receiver has a simple structure and outperforms other differential schemes of comparable complexity