基于MIMO-OFDM系统的UEP传输方案研究

发布时间：2018-10-13 10:41

【摘要】：在宽带无线通信领域,MIMO-OFDM系统日渐成为保证数据高速、可靠传输的重要手段,而视频数据对信道传输质量的敏感度较一般数据更高,利用UEP分级传输技术可以改善无线信道中的视频传输性能,因此本文旨在研究基于MIMO-OFDM系统的UEP传输方案,所取得的主要研究成果为:1.改进前人提出的ST-OFDM-UEP传输方案,使之成为SF-OFDM-UEP传输方案,该方案将MIMO-OFDM系统结构与支持UEP传输的分集嵌入式STBC编码结合,并改进STBC码字排布方式为SFBC,即将Alamouti码字排布在相邻OFDM子载波。通过理论分析与仿真验证,证明SF-OFDM-UEP方案与ST-OFDM-UEP方案相比,能够更好地抵抗多普勒频移的影响,从而其应用范围扩展到高速移动无线传输场合。此外还通过仿真研究了一些系统相关设定对传输性能的影响,包括导频安插方式、IFFT长度(OFDM子载波数目)、以及导频插入间隔。2.改进前人提出的频域信道划分-反馈机制UEP传输方案,通过在空间、频域两个维度进行信道质量评估、分组,并通过合理的反馈机制、帧结构的设计,使得发送端各优先级数据流被分配的子信道组具有不均等的传输可靠性,即将信道资源按传输质量进行重新分配,从而实现UEP分级传输。针对4×4阵列结构的MIMO-OFDM系统以及给定分级需求,设计了三种不同的信道划分方案,通过仿真验证给出其与原方案性能的比较,并从分级性能及频谱效率两方面对几种方案进行评价。
[Abstract]:In the field of wideband wireless communication, MIMO-OFDM system is becoming an important means to ensure the high speed and reliable transmission of data, and the sensitivity of video data to the quality of channel transmission is higher than that of general data. The video transmission performance in wireless channel can be improved by using UEP hierarchical transmission technology. Therefore, this paper aims to study the UEP transmission scheme based on MIMO-OFDM system. The main research results are as follows: 1. The proposed ST-OFDM-UEP transmission scheme is improved to become a SF-OFDM-UEP transmission scheme. This scheme combines the MIMO-OFDM system structure with the diversity embedded STBC coding that supports UEP transmission, and improves the STBC codeword placement method for SFBC, to arrange Alamouti codewords in adjacent OFDM subcarriers. Through theoretical analysis and simulation, it is proved that SF-OFDM-UEP scheme can resist the influence of Doppler frequency shift better than ST-OFDM-UEP scheme, so its application scope is extended to high-speed mobile wireless transmission field. In addition, the effects of some system related settings on transmission performance are studied by simulation, including pilot placement, IFFT length (number of OFDM subcarriers), and pilot insertion interval. 2. To improve the frequency domain channel partition-feedback mechanism UEP transmission scheme, channel quality evaluation in space and frequency domain, grouping, and the design of frame structure through reasonable feedback mechanism, The sub-channel groups assigned to each priority data stream at the sender have unequal transmission reliability, that is to say, channel resources are reallocated according to transmission quality, so that UEP hierarchical transmission is realized. For the MIMO-OFDM system with 4 脳 4 array structure and given hierarchical requirements, three different channel partitioning schemes are designed and compared with the original scheme by simulation. Several schemes are evaluated in terms of classification performance and spectrum efficiency.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53

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