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: Research Article Capacity of Time-Hopping PPM and PAM UWB Multiple Access Communications over Indoor Fading Channels | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 273018 9 pages doi 2008 273018 Research Article Capacity of Time-Hopping PPM and PAM UWB Multiple Access Communications over Indoor Fading Channels Hao Zhang1 and T. Aaron Gulliver2 1 Department of Electrical Engineering Ocean University of China 5 Yushan Road Qingdao 266003 China 2 Department of Electrical Computer Engineering University of Victoria . Box 3055 STN CSC Victoria BC Canada V8S 4W9 Correspondence should be addressed to Hao Zhang zhanghao@ Received 27 June 2007 Revised 10 October 2007 Accepted 10 February 2008 Recommended by Weidong Xiang The capacity of time-hopping pulse position modulation PPM and pulse amplitude modulation PAM for an ultra-wideband UWB communication system is investigated based on the multipath fading statistics of UWB indoor wireless channels. A frequency-selective fading channel is considered for both single-user and multiple-user UWB wireless systems. A Gaussian approximation based on the single-user results is used to derive the multiple access capacity. Capacity expressions are derived from a signal-to-noise-ratio SNR perspective for various fading environments. The capacity expressions are verified via Monte Carlo simulation. Copyright 2008 H. Zhang and T. A. Gulliver. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Ultra-wideband UWB 1 communication systems employ ultrashort impulses to transmit information which spreads the signal energy over a very wide frequency spectrum of several GHz. Multipath fading is one of the major challenges faced by UWB systems. The statistics of narrowband indoor wireless channels have been extensively investigated and several widely accepted channel models have been developed. However .
