空间调制与大规模MIMO传输关键技术研究

发布时间：2018-03-29 10:38

本文选题：多输入多输出　切入点：空间调制　出处：《西南交通大学》2016年博士论文

【摘要】：空间调制(spatial modulation, SM)和空移键控(space shift keying, SSK)是一类新型的多输入多输出(Multiple-Input Multiple-Output, MIMO)传输技术。与传统MIMO传输技术相比,空间调制和空移键控具有复杂度低、需要更少射频(radio frequency, RF)链路等优点。大规模MIMO (Massive MIMO)传输技术在基站端配置大量天线,利用各用户信道间的渐近正交性,可通过简单的线性信号处理实现多用户接入,同时避免用户间的干扰。本论文主要工作为对空间调制、空移键控和大规模MIMO传输技术的改进和应用。本文首先研究了空移键控传输中的发射和接收天线选择,提出了一种降低反馈量的发射天线选择方案(Fix-1)以及低计算复杂度的发射和接收天线选择算法,推导出了所提算法的精确误码率(bit error rate, BER)表达式以及误码率上界的闭合表达式。接着,本文提出一种发射天线受限的分布式广义空移键控传输系统(generalized SSK,GSSK),其中多个分布式的基站联合构成一个GSSK传输系统。在该系统中,每个基站只配置一套射频链路,所以同一时刻每个基站只能有一根发射天线被激活。由于各基站地理位置不同,其发射的信号将经历不同的大尺度衰落,该特点可用于改善系统性能。本文首先推导出了该分布式GSSK的误符号率(symbol error rate, SER)表达式,在此基础上基于凸优化方法提出了一种最小化误符号率的功率分配算法。然后,本文将空移键控应用于高速铁路(high speed railway, HSR)无线通信中,将该环境下的无线信道建模为对数正态—莱斯(Lognormal-Rician)混合信道。本文完成了空移键控传输在该信道下的误符号率分析,并结合高铁无线通信的信道特点,比较了不同天线放置方式对系统错误性能的影响。根据分析结果,提出一种结合多点协作(coordinated multiple point, CoMP)传输的空移键控传输方案,该方案可利用阴影衰落的低相关性来降低系统误符号率,同时避免了分布式天线结构带来的发射端功率损耗。接下来,本文针对空间调制多用户接入系统,提出一种基于子空间投影的多用户检测算法,在此基础上结合改进的广义可变空间期望最大化(space-alternating generalized expectation-maximization, SAGE)算法,提出了一种SAGE辅助的投影检测算法。该检测方法的性能可以接近性能最优的最大似然检测(maximum-likelihood detection, MLD)和球型译码(sphere decoding, SD)检测,同时在系统规模较大时能有效地降低计算复杂度。最后,本文提出一种基于时分双工(time division duplex, TDD)、正交频分复用(orthogonal frequency division multiplexing, OFDM)和大规模MIMO传输技术的下行多用户传输结构。在该传输结构中每个用户均使用整个带宽,可以节省用户调度的信令开销。本文推导出采用最大似然估计(maximum likelihood estimation, MLE)和最小均方误差(minimum mean square error estimation, MMSE)准则进行信道估计时系统的容量表达式。基于该结果,得到了大信噪比下最优的用户数量和导频序列长度,并分析了衰落信道的时间和频率选择性对系统容量的影响,最后提出一种基于用户信道多径时延差异的功率分配方法以提高系统容量。
[Abstract]:Spatial modulation (spatial modulation, SM) and space shift keying (space shift, keying, SSK) is a new type of multi input multi output (Multiple-Input Multiple-Output MIMO) transmission technology. Compared with the traditional MIMO transmission technology, spatial modulation and space shift keying with low complexity and requires less RF (radio frequency. RF link) and other advantages. Large scale MIMO (Massive MIMO) transmission technology in base station configuration of a large number of antennas, the asymptotic orthogonality between each user's channel, can be realized by multi user access linear simple signal processing, to avoid interference between users at the same time. The main work of this thesis is on the improvement and application of empty space modulation. Shift keying and large-scale MIMO transmission technology. This paper studies the space shift keying transmission in transmitting and receiving antenna selection, this paper put forward a selection scheme to reduce the amount of feedback of the transmitting antenna (Fix-1) and low The computational complexity of transmitting and receiving antenna selection algorithms and derive the exact bit error rate of the proposed algorithm (bit error rate, BER) expression and the upper bound of BER closed expressions. Then, this paper presents a generalized distributed antenna with limited space shift keying transmission system (generalized SSK GSSK), which joint base station multiple distributed constitute a GSSK transmission system. In this system, each base station is configured with only a set of radio links, so the same time each base station only one transmitting antenna is activated. Due to the different geographical location of each base station, the transmitted signal will experience different large scale fading, this feature can be to improve the performance of the system. This paper firstly deduced the symbol error rate of GSSK (symbol distributed error rate, SER) expression, convex optimization method has a minimum symbol error rate based on power The rate allocation algorithm. Then, the null shift keying is applied in high-speed railway (high speed, railway, HSR) in wireless communication, wireless channel modeling of the environment for the lognormal - Les (Lognormal-Rician) hybrid channel. The space shift keying rate of transmission in the channel error the symbol, and combine the channel characteristics of the high-speed railway wireless communication, compares the different effects of antenna placement methods on system error performance. According to the results of the analysis, put forward a combination of Coordinated Multi point (coordinated multiple point, CoMP) transmission space shift keying transmission scheme, the scheme can use low correlation to reduce the shadow fading system symbol error rate, while avoiding the transmitter power loss distributed antenna structure. Then, according to the spatial modulation multiple access system, proposes a multi-user detection algorithm based on subspace projection, in The improvement of this generalized variable space based on the combination of expectation maximization (space-alternating generalized expectation-maximization SAGE) algorithm, presents a projection SAGE aided detection algorithm. The maximum likelihood detection performance of the detection method can approach the optimal performance of the (maximum-likelihood, detection, MLD) and sphere decoding (sphere decoding, SD) detection, at the same time in the large scale system can effectively reduce the computational complexity. Finally, this paper puts forward a kind of based on time division duplex (time division, duplex, TDD), orthogonal frequency division multiplexing (orthogonal frequency division multiplexing, OFDM) downlink MIMO transmission technology and large-scale multi-user transmission structure. In the transmission structure of each user are used throughout the user can save bandwidth, signaling overhead scheduling. This paper deduces the use of maximum likelihood estimation (maximum likelihood estimation , MLE) and minimum mean square error (minimum mean square error estimation, MMSE) criterion to estimate the channel capacity expression system. Based on the results obtained under high SNR optimal pilot sequence length and the number of users, and analyzes the effect of time and frequency selective fading channels on the system capacity, finally proposed to improve the system capacity based on user power allocation method for multipath time delay difference.

【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN919.3

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