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: Particle Filtering for Joint Symbol and Code Delay Estimation in DS Spread Spectrum Systems in Multipath | EURASIP Journal on Applied Signal Processing 2004 15 2306-2314 2004 Hindawi Publishing Corporation Particle Filtering for Joint Symbol and Code Delay Estimation in DS Spread Spectrum Systems in Multipath Environment Elena Punskaya Signal Processing Laboratory Department of Engineering University of Cambridge Trumpington Street Cambridge CB2 1PZ UK Email op205@ Arnaud Doucet Signal Processing Laboratory Department of Engineering University of Cambridge Trumpington Street Cambridge CB2 1PZ UK Email ad2@ William J. Fitzgerald Signal Processing Laboratory Department of Engineering University of Cambridge Trumpington Street Cambridge CB2 1PZ UK Email wjf@ Received 19 June 2003 Revised 18 June 2004 We develop a new receiver for joint symbol channel characteristics and code delay estimation for DS spread spectrum systems under conditions of multipath fading. The approach is based on particle filtering techniques and combines sequential importance sampling a selection scheme and a variance reduction technique. Several algorithms involving both deterministic and randomized schemes are considered and an extensive simulation study is carried out in order to demonstrate the performance of the proposed methods. Keywords and phrases direct sequence spread spectrum system multipath fading particle filters signal detection synchronization. 1. INTRODUCTION Direct sequence DS spread spectrum systems are robust to many channel impairments allow multiuser CDMA and low-detectability signal transmission and therefore are widely used in different areas of digital communications. Unlike many other communication systems however spread spectrum receivers require additional code synchronization which can be a rather challenging task under conditions of multipath fading when severe amplitude and phase variations take place. The problem of joint symbol delay and multipath estimation has been addressed in the literature before see . 1 2 and proved to be
