Timing Acquisition with Noisy Template for Ultra-Wideband Communications in Dense Multipath

Abstract

Timing acquisition is critical to enabling the potential of ultra-wideband (UWB) radios in high-speed, short-range indoor wireless networking. An effective timing acquisition method should not only operate at a low sampling rate to reduce implementation complexity and synchronization time, but also be able to collect sufficient signal energy in order to operate in a reasonable transmit SNR regime. Energy capture for time-hopping impulse-radio transmissions in dense multipath is particularly challenging during the synchronization phase, in the absence of reliable channel and timing information. In this paper, we develop an efficient sampling strategy for correlation-based receivers to accomplish adequate energy capture at a low cost, using a noisy correlation template constructed directly from the received waveform. Merging our sampling operation based on noisy template with low-complexity timing acquisition schemes, we derive enhanced cyclostationarity-based blind synchronizers, as well as data-aided maximum likelihood timing offset estimators, all operating at a low frame rate. Both analysis and simulations confirm evident improvement in timing performance when using our noisy template, which makes our low-complexity timing acquisition algorithms attractive for practical UWB systems operating in dense multipath.