关键词: OFDM, PAPR, 频带利用率, 频域均衡, 符号间干扰, 信道间干扰

Abstract: A system level comparison between a conventional OFDM(orthogonal frequency division multiplexing) and the Multi-Symbol Encapsulated (MSE)-OFDM system is presented in this study. An analysis onimpact of frequency offset on the system performance is presented. Comparisonsare made on two different assumptions, i.e., either keeping the symbol size of the MSE-OFDM (i.e., number of the subcarriers) unchanged to increase the bandwidth efficiency, or keeping the bandwidth efficiency unchanged (ratio between CP(cyclic prefix) and useful data transmission time) for system robustness to synchronization errors, i.e., frequency offset. In the first case for CP-reduced MSE-OFDM, bandwidthefficiency is improved due to a reduced number of CPs inserted between OFDM symbols. For the latter case of FFT size-reduced MSE-OFDM, robustness to synchronization errors is improved considerably due to the smaller number of subcarriers. The proposed system is of particular interest for fixed wireless systems and digital subscriber loops (DSL). Large frame size can be used in these applications, due to the static nature of the channel conditions. Implementation complexity ofthe MSE-OFDM system is also discussed.\=Key words:orthogonal frequency division multiplexing; peak to average power ratio; bandwidth efficiency; frequency domain equalization; intersymbol interference; interchannel interferenceCLC number: TN911 Document code: A   收稿日期: 2004-07-08   作者简介: Y. Wu Fellow, IEEE, and X. Wang Member, IEEE are with Communications Research Centre Canada, Carling Ave., Box 11490, Station H, Ottawa, ON K2H 8S2 Canada. E-mail: yiyan.wu, xianbin.wang@crc.caMSE-OFDM——一种基于分组的OFDM宽带通信系统吴奕彦, 王现斌(加拿大渥太华通信研究中心, 渥太华 11490, 加拿大)摘要: 本文对传统OFDM和多符号封装(MSE)-OFDM进行了系统比较。分析了频率偏移对系统性能的影响。比较在2种不同的假设下进行,即或者保持MSE-OFDM的符号长度(即子载波数)不变以提高频带利用率,或者保持频带利用率(CP与数据有效传输时间之比)不变以改善系统对抗同步误差,即频率偏差的能力。在第一种降CP的MSE-OFDM情形下,由于减少了OFDM符号之间插入的CP数,频带利用率得以提高;对于后一种降FFT长度的MSE-OFDM情形,更少的子载波数显著改善了对同步误差的抵抗能力。本文提出的系统尤其适合于固定无线系统和数字用户环路(DSL)。在这些应用中,由于信道环境的静止特性,可以使用很大的帧长度。文中还讨论了MSE-OFDM系统的复杂度。

Key words: orthogonal frequency division multiplexing, peak to average power ratio, bandwidth efficiency, frequency domain equalization, intersymbol interference, interchannel interference CLC numberTN911 Document codeA