In this article, a novel transmit-reference （TR） signaling scheme is proposed for ultra-wideband （UWB） system, where by invoking m-sequence codes the reference and data pulses can be transmitted side by side to increase the data rate. This structure enables demodulation with a simple and practical autocorrelation receiver despite existence of severe inter-pulse interference （IPI） To evaluate detection performance of the new designs, closed-form expression for bit error probability （BRP） is theoretically derived and simulation results confirm the analytical results. In addition, the proposed scheme can be extended to M-ary systems to further improve the data rate and power efficiency.
ZHAO Lin-li,Lü Tie-jun,QIAO Yong-wei School of Information and Communication Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,China
One of the biggest challenges in ultra-wideband （UWB） radio is the accurate timing acquisition for the receiver. In this article, we develop a novel data-aided synchronization algorithm for pulses amplitude modulation （PAM） UWB systems Pilot and information symbols are transmitted simultaneously by an orthogonal code division multiplexing （OCDM） scheme. In the receiver, an algorithm based on the minimum average error probability （MAEP） of coherent detector is applied to estimate the timing offset. The multipath interference （MI） problem for timing offset estimation is considered. The mean-square-error （MSE） and the bit-error-rate（BER） performances of our proposed scheme are simulated. The results show that our algorithm outperforms the algorithm based on the maximum correlator output （MCO） in multipath channels.
A new blind （non-data-aided） synchronization algorithm based on direct-sequence （DS） codes is proposed for ultra-wideband （UWB） systems. The proposed approach fully exploits prior knowledge of DS codes and bypasses channel estimation. The real-time acquisition is achieved using integrating-and-dumping （I＆D） operation and DS codes matching filter. Because of pseudo randomicity and periodicity of DS codes, both the speed and the accuracy of synchronization are improved significantly. A lower bound on the acquisition probability of the proposed approach is also derived. Simulations confirm performance improvement of the proposed algorithm relative to existing alternatives in terms of acquisition probability, normalized mean square error （NMSE）, and bit error rate （BER）.
QIAO Yong-wei,L Tie-jun,REN Zhi-yuan School of Information Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,China
