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Báo cáo hóa học: " Performance and Capacity of PAM and PPM UWB Time-Hopping Multiple Access Communications with Receive Diversity"

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: Performance and Capacity of PAM and PPM UWB Time-Hopping Multiple Access Communications with Receive Diversity | EURASIP Journal on Applied Signal Processing 2005 3 306-315 2005 Hindawi Publishing Corporation Performance and Capacity of PAM and PPM UWB Time-Hopping Multiple Access Communications with Receive Diversity Hao Zhang Department of Electrical Computer Engineering University of Victoria BC Canada V8W 3P6 Email hzhang@ece.uvic.ca T. Aaron Gulliver Department of Electrical Computer Engineering University of Victoria BC Canada V8W 3P6 Email agullive@ece.uvic.ca Received 29 September 2003 Revised 9 April 2004 The error probability and capacity of a time-hopping ultra-wideband UWB communication system with receive diversity are investigated. We consider pulse amplitude modulation PAM and pulse-position modulation PPM over additive white Gaussian channels for a single-user system. A multiuser environment with PPM is also investigated. It is shown that the communication distance and error performance are improved by employing receive diversity. The channel capacity of PPM and PAM is determined subject to the power constraints of FCC part 15 rules to illustrate the relationship between reliable communication distance and signal-to-noise ratio. The error probability with PAM and receive diversity is derived for the single-user case. The error probability and performance bounds with PPM are derived for both the single-user and multiuser cases. Keywords and phrases ultra-wideband communications PAM PPM multiple access channel capacity. 1. INTRODUCTION An ultra-wideband UWB 1 communication system transmits information using ultrashort impulses that spread the energy of the signal typically from near DC to several GHz. Unlike conventional communication systems UWB systems operate at baseband and thus involve no intermediate frequency and no carrier synchronization. UWB theoretically promises a very high data rate by employing a large signal bandwidth. However due to possible interference to existing communication systems power spectrum density limitations such as FCC part 15 .