无线携能通信网络系统中新型传输方案的研究

发布时间：2018-05-12 03:43

本文选题：无线携能通信 + 无线能量传输　；参考：《东南大学》2017年博士论文

【摘要】：无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)是无线通信技术与无线能量传输技术交叉融合的一个前沿热点研究方向,其利用射频(RF)信号实现信息与能量的并行传输,是解决无线网络能量受限问题以及实现绿色通信的重要途径,已引起学术界和工业界的广泛关注。然而,SWIPT系统面临着信道衰落和安全通信等方面的严峻挑战。因此,研究如何实现SWIPT系统高效的能量传输以及安全的信息传输具有重要的现实意义。在传统无线网络中,多天线预编码技术可以有效减小信道衰落带来的影响,而物理层安全技术可以保证通信的安全性。因此,结合多天线预编码技术和物理层安全技术,本论文主要研究了 MISO SWIPT系统中基于能量获取比例公平的波束成形,MIMO SWIPT系统中基于安全能效最大化的预编码,具有秘密消息的MISO SWIPT广播信道安全传输方案,具有额外窃听者及秘密消息的MISO SWIPT广播信道安全传输方案,无线能量传输与认知无线电共存场景下的协作预编码,无线能量传输与无线信息传输共存场景下的多目标预编码。具体研究内容和主要贡献如下:1.针对多用户MISO SWIPT系统中存在能量获取不均衡的问题,提出了一种基于能量获取比例公平的波束成形设计方案。通过优化波束成形矢量,所提方案在满足信息接收者的信干噪比和发送者的最大发送功率等约束的基础上可以实现能量获取的比例公平。此设计在数学上是一个很难直接求解的非凸优化问题。为此,我们首先将原优化问题等价为容易处理的上镜图形式,然后利用半定松弛技术将对应的非凸优化问题转化为凸优化问题。另外,在发送者仅知道部分信道状态信息的情况下,我们进一步采用最差性能最优的方法对原优化问题进行了鲁棒波束成形设计。仿真结果表明,所提波束成形方案可以实现能量获取的比例均衡。2.针对三节点MIMO SWIPT窃听系统,提出了一种安全能量效率优先的预编码传输方案。SWIPT系统中以安全能量效率为设计准则的预编码设计仍是一个开放性问题,类比于传统无线网络中能量效率的定义,本文将安全能量效率定义为系统的最大可达安全速率除以系统的总消耗功率。该预编码设计方案可以在满足安全速率、能量获取以及最大发送功率等约束的基础上最大化系统的安全能量效率。非凸安全速率约束导致原优化问题很难求解。为此,提出了一个基于一阶泰勒级数展开的迭代算法,并证明了所提迭代算法的收敛性。仿真结果表明,所提算法可以实现安全能量效率的最大化,并且在小发送功率区域,该算法还可以同时最大化系统的安全速率。3.考虑了具有保密消息的MISO SWIPT广播信道场景,并提出了一个基于总发送功率最小化的安全传输方案。该方案通过联合优化发送波束成形矢量、噪声协方差矩阵以及接收者功率划分因子,在满足每个接收者的安全速率和能量获取约束的基础上实现总发送功率最小化。同时,提出了一个基于两阶段优化的迭代算法来求解原优化问题。具体来讲,首先固定每个接收者的信干噪比进而通过半定松弛技术得到对应问题的全局最优解,然后通过欠维穷举搜索的方式获得原优化问题的最优解。另外,考虑到K维穷举搜索的运算复杂度过高,进一步提出了一个基于遗传算法的低复杂度次优算法来求解原优化问题。4.针对具有保密消息的MISO SWIPT广播信道中发送者发送给每个接收者的秘密消息还有可能被额外窃听者窃听的问题,进一步研究了具有额外窃听者及秘密消息的MISO SWIPT系统的安全传输方案设计。该方案以最小化系统的总发送功率为设计目标,同时考虑每个接收者的安全速率和能量获取要求。类似地,首先提出了一个基于两阶段优化的算法来处理原非凸优化问题,然后进一步提出了,一个基于粒子群算法的低复杂度次优算法。随后,将上述安全波束设计推广到合作窃听的情况。所谓合作窃听是指额外窃听者和潜在窃听者组成一个虚拟的多天线窃听者,从而保密消息面临更为严重的安全威胁。此情况下约束集中包含行列式函数,因此对应优化问题的求解面临更大的挑战。基于两阶段优化的框架,本文通过采用基本的矩阵不等式结果以及半定松弛技术对相应的优化问题进行了有效的求解。最后,考虑发送者仅知道部分信道状态信息的情况,进一步提出了鲁棒安全传输方案设计。5.考虑了无线能量传输系统与认知无线电系统共存的场景,并设计了一种积极利用同频干扰的协作预编码传输方案。与传统的无线通信网络不同,此场景下同频干扰被视为有益的资源而不是有害的因素。具体来讲,认知无线电系统中的次用户产生的同频干扰对无线能量传输系统中的能量接收者来说是一个能量源,因此此同频干扰为有益的。同时,无线能量传输系统中的能量发送者产生的同频干扰对认知无线电系统来说是一种人工噪声,可以帮助其实现安全通信,因此也是有益的。针对此场景,所提协作预编码传输方案以和发送功率最小化为设计准则,同时考虑认知无线电系统中次用户的安全速率、主用户的干扰温度以及无线能量传输系统中能量接收者的能量获取等要求。通过利用一阶泰勒级数展开和拉格朗日对偶分解的方法,提出了一个迭代算法来求解原设计对应的非凸优化问题。此外,证明了所提算法可以单调收敛到原优化问题的一个KKT点,并分析了所提算法的复杂度。仿真结果表明,所提协作预编码设计方案可以同时减小次用户的发送功率以及能量发送者的发送功率。6.针对无线能量传输与无线信息传输共存场景下多个设计目标之间存在冲突的问题,提出了一种多目标预编码传输方案设计来平衡此共存场景下多个设计目标之间的冲突。具体来讲,基于多目标优化框架,将安全传输协方差设计建模成多目标优化问题,从而可以实现无线能量传输系统中的获取能量和无线信息传输系统中的安全速率同时最大化。为求解此非凸多目标优化问题,本文首先得到其对应的乌托邦点。然后,利用加权和以及加权切比雪夫的方法将原多目标优化问题转化为两个单目标优化问题,并设计了求解每个单目标优化问题的迭代算法。另外,进一步提出了一个基于非合作博弈的分布式预编码设计,并证明了纳什均衡解的存在性和唯一性。
[Abstract]:Simultaneous Wireless Information and Power Transfer (SWIPT) is a hot research direction in the cross fusion of wireless communication technology and wireless energy transmission technology. It uses radio frequency (RF) signal to realize the parallel transmission of information and energy. It is a problem of solving the problem of wireless network energy limitation and realizing green communication. An important approach has attracted wide attention from academic and industrial circles. However, SWIPT systems are facing severe challenges in channel fading and security communication. Therefore, it is important to study how to achieve efficient energy transmission and secure information transmission in SWIPT systems. In traditional wireless networks, multi antenna precoding techniques are used. It can effectively reduce the influence of channel fading, and the physical layer security technology can guarantee the security of communication. Therefore, combining multi antenna precoding and physical layer security technology, this paper mainly studies the beamforming based on energy gain proportional fairness in the MISO SWIPT system, and the MIMO SWIPT system is based on the maximum security energy efficiency. Precoding, MISO SWIPT broadcast channel security transmission scheme with secret message, MISO SWIPT broadcast channel security transmission scheme with additional eavesdropper and secret message, cooperative precoding under the coexistence scene of wireless energy transmission and cognitive radio, multi target preconditioning under the coexistence scene of wireless energy transmission and wireless information transmission The specific research content and main contributions are as follows: 1. in view of the problem of unbalanced energy acquisition in the multiuser MISO SWIPT system, a beamforming scheme based on energy gain proportional fairness is proposed. By optimizing the beamforming vector, the proposed scheme satisfies the signal to noise ratio of the receiver and the maximum sender's hair. This design is a non convex optimization problem which is difficult to solve directly in mathematics. For this reason, we first equip the original optimization problem as an easy to handle form of the upper mirror, and then transform the corresponding non convex optimization problem into a convex optimization question by using the semidefinite relaxation technique. In addition, in the case that the sender only knows some channel state information, we use the worst performance optimal method to carry out robust beamforming design for the original optimization problem. The simulation results show that the proposed beamforming scheme can achieve the proportional balance.2. of the energy acquisition for three node MIMO SWIPT eavesdropping system. A precoding scheme of secure energy efficiency precoding scheme.SWIPT system with security energy efficiency as the design criterion is still an open problem, which is analogous to the definition of energy efficiency in traditional wireless networks. In this paper, the security energy efficiency is defined as the maximum reachable security rate of the system by the total system consumption. Power. The precoding scheme can maximize the security energy efficiency of the system on the basis of satisfying the constraints of security rate, energy acquisition and maximum transmission power. The original optimization problem is difficult to be solved by non convex security rate constraints. An iterative algorithm based on first order Taylor series expansion is proposed, and the proposed algorithm is proved to be proposed. The convergence of the iterative algorithm shows that the proposed algorithm can maximize the efficiency of security energy, and the algorithm can simultaneously maximize the security rate.3. of the system to consider the MISO SWIPT broadcast channel scene with the secret message at the small transmission power region, and propose a minimum total transmission power based on the minimization of the total transmission power. The scheme is designed to minimize the total transmission power by combining the beam forming vector, the noise covariance matrix and the receiver power division factor by joint optimization, and to minimize the total transmission power on the basis of each receiver's safety rate and energy acquisition constraints. At the same time, an iterative algorithm based on two phase optimization is proposed to solve the original. In particular, firstly, the SNR of each receiver is fixed, and then the global optimal solution of the corresponding problem is obtained by the semidefinite relaxation technique, and then the optimal solution of the original optimization problem is obtained by the way of the underdimension exhaustive search. In addition, considering the high complexity of the K dimension exhaustive search, a further based on the remains is proposed. The low complexity suboptimal algorithm for the transmission algorithm to solve the original optimization problem.4., the security transmission of the secret message sent to each recipient in the MISO SWIPT broadcast channel with confidential messages and the eavesdropper of the additional eavesdropper is further studied. The secure transmission of the MISO SWIPT system with the additional eavesdropper and secret message is further studied. The scheme is designed to minimize the total transmission power of the system as a design goal, while taking into account the safety rate and energy requirements of each recipient. Similarly, a two phase optimization algorithm is proposed to deal with the original non convex optimization problem. Then, a low complexity based on particle swarm optimization is proposed. Suboptimal algorithm. Then, the above security beam design is extended to cooperative eavesdropping. The so-called cooperative eavesdropping refers to a virtual multi antenna eavesdropper consisting of additional listeners and potential eavesdroppers, and the secret message faces a more serious security threat. In this case, the constraint focus contains the determinant function and therefore corresponds to the optimization problem. Based on the two stage optimization framework, this paper makes an effective solution to the corresponding optimization problem by using the basic matrix inequalities and semidefinite relaxation technique. Finally, considering the sender only knowing the state information of the partial channel state, the robust secure transmission scheme.5. is further proposed. Considering the coexistence of wireless energy transmission system and cognitive radio system, a cooperative precoding transmission scheme which actively uses the same frequency interference is designed. Unlike the traditional wireless communication network, the same frequency interference is considered as a useful resource rather than a harmful factor. The same frequency interference generated by the user is an energy source for the energy receiver in the wireless energy transmission system. Therefore, the same frequency interference is beneficial. At the same time, the same frequency interference produced by the energy sender in the wireless energy transmission system is a kind of human noise to the cognitive radio system, which can help it to realize secure communication. It is also beneficial. For this scenario, the proposed cooperative precoding transmission scheme is designed to minimize the transmission power, considering the security rate of the secondary users in the cognitive radio system, the interference temperature of the main user and the energy receiver in the wireless energy transmission system. By using the first order Taylor series expansion. An iterative algorithm is proposed to solve the non convex optimization problem of the original design. In addition, it is proved that the proposed algorithm can converge to a KKT point of the original optimization problem monotonically, and the complexity of the proposed algorithm is analyzed. The simulation results show that the proposed cooperative precoding scheme can be reduced at the same time. The transmission power of small subscribers and the transmission power of energy sender.6. are in conflict with multiple design targets in the scene of wireless energy transmission and wireless information transmission. A multi target precoding transmission scheme is designed to balance the conflicts between multiple design targets in this coexistence scene. Based on the multi-objective optimization framework, the covariance design of the secure transmission is modeled as a multi-objective optimization problem, which can achieve the simultaneous maximization of the security rate in the acquisition energy and the wireless information transmission system in the wireless energy transmission system. By using the weighted sum and weighted Chebyshev method, the original multi-objective optimization problem is transformed into two single objective optimization problems, and an iterative algorithm for solving each single objective optimization problem is designed. In addition, a distributed precoding design based on non cooperative game is proposed, and the existence and uniqueness of the Nash equilibrium solution are proved. One sex.

【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN92;TM724

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