多用户MIMO空间调制的预处理技术

发布时间：2018-07-25 15:49

【摘要】：多输入多输出(MIMO)技术以其高复用增益和分集增益等优势,一直是无线通信和信号处理领域的研究重点。MIMO预编码技术可以降低接收端检测复杂度、减小误码率并提高系统容量。因此,对发射信号进行预处理,是当前MIMO系统的主流处理技术。空间调制是近年来提出的一种新颖的多天线传输技术,被广泛应用于单用户MIMO系统,用于减少检测的复杂度、消除符号间干扰。实际上,多用户MIMO系统是未来通信技术的主流方向。研究表明,对多用户MIMO空间调制系统在发射端进行适当的预处理,可以避免多用户MIMO带来的内部信道干扰(ICI),消除用户间干扰,并提高系统性能。论文主要针对多用户MIMO空间调制系统的发射机预处理和功率分配问题进行了研究,具体研究内容如下： (1)：介绍了MIMO预编码技术,分析了单用户MIMO和多用户MIMO预编码模型及几种较为典型的预编码方法,包括迫零预编码、最小均方误差预编码、奇异值分解预编码和块对角化预编码,并分析了各自的优缺点。 (2)：研究了将发射机预编码应用于多用户MIMO空间调制系统。首先通过块对角化预编码器,完全消除用户间干扰,将多用户MIMO变为多个具有平行信道的单用户MIMO;其次,对每个独立的单用户MIMO系统进行接收空间调制,通过接收天线序号和传统幅度相位调制同时携带信号,有效地避免了天线间干扰,并减低接收端检测复杂度。在多用户MIMO空间调制预处理系统中,通过理论计算得出功率分配因子与系统误码率上边界值的函数关系,使用梯度下降方法解出了各用户的功率分配因子。将系统在该功率分配因子情形下与未进行功率分配的情形下进行误码率上边界的对比。得出结论为系统经功率分配后,误码率上边界明显降低。
[Abstract]:Because of its advantages of high multiplexing gain and diversity gain, multi-input and multi-output (MIMO) technology has been a research focus in the field of wireless communication and signal processing. MIMO-precoding technology can reduce the detection complexity, reduce the bit error rate and improve the system capacity. Therefore, preprocessing the transmitted signal is the mainstream processing technology of MIMO system at present. Spatial modulation is a novel multi-antenna transmission technology proposed in recent years. It is widely used in single-user MIMO systems to reduce the complexity of detection and to eliminate inter-symbol interference. In fact, multi-user MIMO system is the main direction of communication technology in the future. The research shows that the multi-user MIMO spatial modulation system can be pretreated properly at the transmitter, which can avoid the internal channel interference caused by the multi-user MIMO and eliminate the inter-user interference, and improve the performance of the system. This paper mainly focuses on the transmitter preprocessing and power allocation of multi-user MIMO spatial modulation system. The main contents are as follows: (1) the MIMO precoding technology is introduced. The precoding models of single user MIMO and multiuser MIMO and several typical precoding methods are analyzed, including zero forcing precoding, minimum mean square error precoding, singular value decomposition precoding and block diagonalization precoding. Their advantages and disadvantages are analyzed. (2) the application of transmitter precoding to multi-user MIMO spatial modulation system is studied. Firstly, the block diagonalization precoder is used to completely eliminate interuser interference and transform the multi-user MIMO into multiple single-user MIMOs with parallel channels. Secondly, each independent single-user MIMO system is modulated by receiving space. The received antenna sequence number and the traditional amplitude and phase modulation simultaneously carry the signal, which effectively avoids the inter-antenna interference and reduces the detection complexity of the receiver. In the multi-user MIMO spatial modulation preprocessing system, the function relationship between the power allocation factor and the boundary value on the bit error rate of the system is obtained by theoretical calculation, and the power allocation factor of each user is solved by using gradient descent method. The BER upper boundary is compared between the power allocation factor and the power allocation. It is concluded that the upper boundary of BER decreases obviously after power allocation.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.3

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