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Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Timing Acquisition with Noisy Template for Ultra-Wideband Communications in Dense Multipath | EURASIP Journal on Applied Signal Processing 2005 3 439-454 2005 Hindawi Publishing Corporation Timing Acquisition with Noisy Template for Ultra-Wideband Communications in Dense Multipath Zhi Tian Department of Electrical and Computer Engineering Michigan Technological University Houghton MI 49931 USA Email ztian@mtu.edu Lin Wu Department of Electrical and Computer Engineering Michigan Technological University Houghton MI 49931 USA Email liwu@mtu.edu Received 1 October 2003 Revised 5 March 2004 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. Keywords and phrases UWB timing acquisition dense multipath energy capture cyclostationarity data-aided estimation. 1. INTRODUCTION Ultra-wideband UWB communications have .
