tailieunhanh - Báo cáo hóa học: " Research Article Spatial Capacity of UWB Networks with Space-Time Focusing Transmission"

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 Spatial Capacity of UWB Networks with Space-Time Focusing Transmission | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010 Article ID 678490 12 pages doi 2010 678490 Research Article Spatial Capacity of UWB Networks with Space-Time Focusing Transmission Yafei Tian and Chenyang Yang School of Electronics and Information Engineering Beihang University Beijing 100191 China Correspondence should be addressed to Yafei Tian ytian@ Received 3 August 2010 Accepted 29 November 2010 Academic Editor Claude Oestges Copyright 2010 Y. Tian and C. Yang. 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. Space-time focusing transmission in impulse-radio ultra-wideband IR-UWB systems resorts to the large number of resolvable paths to reduce the interpulse interference as well as the multiuser interference and to simplify the receiver design. In this paper we study the spatial capacity of IR-UWB systems with space-time focusing transmission where the users are randomly distributed. We will derive the power distribution of the aggregate interference and investigate the collision probability between the desired focusing peak signal and interference signals. The closed-form expressions of the upper and lower bound of the outage probability and the spatial capacity are obtained. Analysis results reveal the connections between the spatial capacity and various system parameters and channel conditions such as antenna number frame length path loss factor and multipath delay spread which provide design guidelines for IR-UWB networks. 1. Introduction Impulse-radio ultra-wideband IR-UWB signals have large bandwidth which can resolve a large number of multipath components in densely scattered channels. For communication links connecting different pairs of users the correlation between multipath channel coefficient vectors is weak even when