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 Outage Performance of Flexible OFDM Schemes in Packet-Switched Transmissions | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2009 Article ID 698417 9 pages doi 2009 698417 Research Article Outage Performance of Flexible OFDM Schemes in Packet-Switched Transmissions Romain Couillet1 2 and Merouane Debbah2 Algorithm Group ST-Ericsson 635 Route des Lucioles 06560 Sophia-Antipolis France 2Department of Telecommunication Alcatel Lucent Chair on Flexible Radio Supelec 3 rue Joliot Curie 91192 Gifsur Yvette France Correspondence should be addressed to Romain Couillet Received 30 January 2009 Revised 18 June 2009 Accepted 7 August 2009 Recommended by Ananthram Swami a-OFDM a generalization of the OFDM modulation is proposed. This new modulation enhances the outage capacity performance of bursty communications. The a-OFDM scheme is easily implementable as it only requires an additional time symbol rotation after the IDFT stage and a subsequent phase rotation of the cyclic prefix. The physical effect of the induced rotation is to slide the DFT window over the frequency spectrum. When successively used with different angles a at the symbol rate a-OFDM provides frequency diversity in block fading channels. Interestingly simulation results show a substantial gain in terms of outage capacity and outage BER in comparison with classical OFDM modulation schemes. The framework is extended to multiantenna and multicellular OFDM-based standards. Practical simulations in the context of 3GPP-LTE called hereafter a-LTE sustain our theoretical claims. Copyright 2009 R. Couillet and M. Debbah. 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 With the recent growth of wireless communications and the increasing demand for high transmission rates orthogonal frequency division multiplexing OFDM is being considered the .
