无线网络串行干扰消除功率控制研究

发布时间：2018-06-24 05:19

本文选题：多用户检测 + 非线性多用户检测　；参考：《合肥工业大学》2016年博士论文

【摘要】：无线通信系统的高带宽和多用户是下一代无线通信技术的发展要求,但随着带宽的提高和用户的增加,无线信道固有的资源有限和信道衰落势必会导致用户之间干扰的加剧,限制了无线通信系统的容量,解决此问题的有效途径是多用户检测技术。近年来,多用户检测技术的研究侧重于其非线性实现方法,包括串行干扰消除、并行干扰消除和迫零判决反馈。其中串行干扰消除由于算法复杂度低、易于实现成为研究的重点。该算法使用迭代方式解出接收的多路混合信号,每一次迭代过程中,在含有多路信号和噪声的混合信号里减去解出的最强一路信号,然后从余下的信号中再选择次强的信号进行循环检测,直到信噪比小于等于给定阈值,检测过程结束。该方法在频谱资源受限的条件下可有效增大无线通信系统的网络吞吐量和用户容量,而串行干扰消除实现的前提是各移动端到达基站的信号强度满足适当的比值范围,这就需要对各移动端的发射功率进行控制。本文针对多移动端单基站CDMA系统的上行传输,以各路信号在基站的信噪比最优为目标,提出了串行干扰消除基于迭代、基于模糊逻辑和基于博弈论的三种功率控制方法。仿真数据表明,本文提出的功率控制方法可有效提高无线通信系统的网络吞吐量和用户容量。本文的主要工作如下：(1)建立了基于信噪比的功率控制模型,为后续研究串行干扰消除的功率控制方法奠定基础。考虑了循环检测过程中信号不完全消除的情况,引入了不完全消除参数,研究了该参数在功率控制模型下与总发射功率减少量的关系,并分析了功率控制误差对信号解码的影响,定义了功率控制误差容限。仿真结果表明各移动端在基站的信号强度按照解码所需形成最佳梯度后,不完全消除参数取最小值与取最大值相比,可大大减少总发射功率。(2)提出了串行干扰消除基于迭代的功率控制方法。考虑了信号消除不完全的情况,建立了迭代功率控制数学表达式,证明了迭代控制可行解的存在,分析了迭代功率控制方法的收敛性与不完全消除参数的关系,研究了变步长迭代功率控制对收敛性的影响,并与已有的三种经典功率控制方法进行对比。静态信道下的仿真结果表明该功率控制方法可有效提高网络吞吐量。(3)提出了串行干扰消除基于模糊逻辑的功率控制方法。推导了移动端节点发射功率选择范围,设计了模糊逻辑功率控制的输入参数,分析了该方法的时间复杂度,提出了实现该功率控制方法的算法流程,并将该方法与已有的三种经典功率控制方法进行仿真比较,结果表明该方法计算复杂度小,具有较好性能,可有效提高网络吞吐量。(4)提出了串行干扰消除基于博弈论的功率控制方法。建立了移动端发射功率的数学表达式,建立了串行干扰消除功率控制的非合作博弈效用函数,证明了纳什均衡的存在,给出了博弈论功率控制算法流程,并与已有的三种经典功率控制方法进行对比。仿真结果表明该方法可大幅度提高网络吞吐量。(5)对所提出的三种功率控制方法的分析和比较。本文对所提出串行干扰消除的三种功率控制方法不仅与已有的经典功率控制方法进行比较,体现本文的研究价值,而且也在它们之间进行了比较。根据三种功率控制方法的计算复杂度、实现难度和功率控制效果的不同,可分别适用于不同的应用环境。
[Abstract]:The high bandwidth and multiuser of the wireless communication system are the development requirements of the next generation wireless communication technology. However, with the increase of bandwidth and the increase of users, the inherent resources of the wireless channel and the fading of the channel will lead to the aggravation of the interference among the users, and the capacity of the wireless communication system is limited. The effective way to solve this problem is to use multipurpose. In recent years, the research of multi user detection technology has focused on its nonlinear implementation, including serial interference cancellation, parallel interference cancellation and zero forcing feedback. The serial interference cancellation is easy to be realized because of the low complexity of the algorithm. The algorithm uses iterative method to solve the received multichannel mixed signal. In each iteration, the strongest signal of the solution is subtracted in a mixed signal containing multiple signals and noise, and then the secondary strong signal is selected from the remaining signal for cyclic detection until the signal to noise ratio is less than equal to a given threshold and the detection process ends. This method can effectively increase the radio frequency under the condition of limited spectrum resources. The network throughput and the user capacity of the communication system, and the realization of the serial interference cancellation is that the signal intensity of each mobile terminal reaches the base station to meet the appropriate ratio range. This requires the control of the transmission power of each mobile terminal. In this paper, the uplink transmission of the single base station CDMA system in the multi mobile terminal is carried out, and the signal to noise in the base station is used. Compared with the optimal target, serial interference cancellation based on three power control methods based on iterative, fuzzy logic and game theory is proposed. The simulation data shows that the proposed power control method can effectively improve the network throughput and user capacity of the wireless communication system. The main work of this paper is as follows: (1) based on the signal-to-noise ratio (SNR) The power control model lays the foundation for the subsequent study of the power control method of eliminating the serial interference. Considering the incomplete elimination of the signal during the cycle detection, the incomplete elimination parameters are introduced, and the relationship between the parameter and the total emission power reduction is studied under the power control model, and the power control error to the signal is analyzed. The influence of decoding, the power control error tolerance is defined. The simulation results show that after the best gradient of the signal intensity of the base station is formed according to the decoding, the total transmission power can be reduced greatly compared with the maximum value. (2) a series line interference elimination based power control method based on iteration is proposed. Considering the incomplete cancellation of the signal, the mathematical expression of iterative power control is established. The existence of the feasible solution of iterative control is proved. The relationship between the convergence of the iterative power control method and the incomplete elimination of the parameters is analyzed. The influence of the variable step length iterative power control on the convergence is studied, and three classical power controllers are used. The simulation results in the static channel show that the power control method can effectively improve the network throughput. (3) the power control method based on the fuzzy logic based on the serial interference elimination is proposed. The range of the transmission power selection of the mobile terminal nodes is derived, the input parameters of the fuzzy logic work rate control are designed, and the time of the method is analyzed. The algorithm flow of the power control method is proposed, and the method is compared with the three classical power control methods. The results show that the method has small complexity, good performance and can effectively improve the network throughput. (4) the power control method based on game theory is proposed. The mathematical expression of the transmitting power of the mobile terminal is established. The non cooperative game utility function of the serial interference elimination power control is established. The existence of Nash equilibrium is proved. The game theory power control algorithm flow is given and compared with the existing three classical power control methods. The simulation results show that this method can greatly improve the network. Throughput. (5) analysis and comparison of the three power control methods proposed in this paper. In this paper, the three power control methods of the proposed serial interference cancellation are compared with the existing classical power control methods, reflecting the research value of this paper, and comparing them. The calculation of the three power control methods is complex. The complexity, difficulty of implementation and power control effect can be applied to different application environments, respectively.
【学位授予单位】：合肥工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN92

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