Time Reversal Based Timing Acquisition for Ultra-Wideband Wireless Communications: Numerical and Experimental Study

A novel timing acquisition method is proposed for ultra-wideband (UWB) wireless communications in dense multipath environments. This method is based on the time reversal technique that employs the temporally reversed channel probing waveforms rather than initial source pulses as the carrier to send the timing preambles. The temporally reversed channel probing waveforms are obtained by simply flipping the channel probing waveforms along the time axis. With the proposed method, the UWB system does not require complicated algorithms to estimate the physical channel at both transmitters and receivers and is capable of recovering the starting time of the transmitted symbols quickly with a very small number of training preamble bits. This is because the focusing properties of the time reversal technology greatly compress the time delay spread of the received preamble pulses and enhance the received pulse energy. A single-input-single-output pulsed UWB radio system is presented to demonstrate the proposed method. Both numerical and experimental results illustrate that the time reversal based timing acquisition method not only speeds up the timing acquisition, but also improves the accuracy of the timing acquisition.