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 The Performance of Relay-Enhanced Cellular OFDMA-TDD Network for Mobile Broadband Wireless Services | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID261815 10 pages doi 2009 261815 Research Article The Performance of Relay-Enhanced Cellular OFDMA-TDD Network for Mobile Broadband Wireless Services Kyungmi Park 1 Hyun S. Ryu 1 Chung G. Kang 1 Daeyoung Chang 2 Seungho Song 2 Jongguk Ahn 2 and Jongtae Ihm2 1 School of Electrical Engineering Korea University Seoul 136-701 South Korea 2SK Telecom Access Network R D Center Seoul 100-999 South Korea Correspondence should be addressed to Chung G. Kang ccgkang@ Received 7 January 2009 Revised 20 April 2009 Accepted 20 May 2009 Recommended by Dmitri Moltchanov A multihop relay MR and repeater are useful means for improving system throughput and coverage in a cellular mobile packet access system as the carrier-to-interference ratio can be improved when deploying them in a heavily shadowed region. In this paper we report on our investigation of bandwidth efficiency and the associated service outage performance for different relay scenarios using system level simulation for a cellular Orthogonal Frequency Division Multiple Access-Time Division Duplexing OFDMA-TDD system. We have demonstrated that network throughput gain by typical optical repeaters which have a simple amplify-and-forwarding capability in a full-duplexing mode could be minimal in open space subject to cochannel interference from all repeaters in the neighboring cells. This is true even though they are generally useful for warranting the outage performance with a multiple order of combining gain especially in the destructive area for example basements or indoors with heavy wall attenuation that naturally shields interference. Meanwhile we show that multihop relays increase the average system capacity almost doubling the system throughput by fully reusing the frequency in every relay station while improving the per-user data rate in the cell edges or improving the outage performance
