能量采集中继网络的资源分配算法研究

发布时间：2019-01-16 01:53

【摘要】：随着移动通信技术的快速发展,用户对于网络质量和数据速率的要求越来越高。协作中继技术的出现有效解决了小区边缘弱覆盖的问题,提高了数据传输速率和用户体验感知,并且能够在一定程度上提供良好的分集增益。能量采集作为近年来出现的一种先进技术,可以从周围环境的可再生资源中收集能量,从而实现绿色通信的目的。因此,协作中继技术与能量采集技术的结合是目前的一个研究热点。本文以具有能量采集功能的多中继网络为研究对象,对网络中的资源分配算法进行了分析,重点对网络中无线节点的功率分配、中继选择、时间分配和子载波配对等问题进行了研究,并提出了三种资源分配算法。本文的主要研究内容如下:(1)在两跳多中继场景下,提出了一种包含功率分配和单中继选择的资源分配算法。该算法以中继节点联合最大发送功率受限和采集能量独立受限为约束条件,以系统中断概率的最小化为目标构建了优化模型,采用拉格朗日乘子法和KKT条件对优化模型进行求解,得到了中继节点的最优发送功率。通过计算中继节点的贡献因子,选择出一个最优中继参与协作。除此之外,本文还对中断概率的下界值进行了推导,给出了中断概率的下界表达式。仿真结果表明,提出的功率分配和单中继选择算法可以有效降低系统的中断概率,并验证了中断概率下界表达式的正确性。(2)在具有能量采集功能的多中继系统中,提出了一种能够提升系统平均吞吐量性能的基于中继选择的时间优化分配算法。该算法中中继节点工作在无线能量传输的能量采集模式下,基于能量因果性和数据因果性的限制,构建了系统端到端吞吐量最大化的优化模型。采用分支定界法对每一个时隙所使用的中继节点进行选择。针对中继节点对剩余能量不同的使用情况,分别采用单纯形法和独立求解法对每个时隙中源节点和中继节点的传输时间进行最优分配,以提高目的节点接收到的数据量。仿真结果表明,提出的中继选择和时间分配算法可以有效提升系统的平均吞吐量。(3)在能量采集OFDM多中继系统中,以系统总容量最大化为优化目标,提出了一种能够有效提升系统性能的功率分配和子载波配对的联合优化算法。该算法中中继节点采用能量分割结构进行信号接收和能量采集,在源节点最大发送功率受限的条件下,根据两跳解码转发协作中继系统的信道容量,求解出中继节点的最优能量分割因子,并以此引出等效信道增益以简化优化问题。通过采用拉格朗日对偶规划和匈牙利算法对子载波配对和节点功率分配问题进行了联合优化。仿真结果表明,提出的资源分配算法可以有效提升系统的平均容量。
[Abstract]:With the rapid development of mobile communication technology, users demand more and more high network quality and data rate. The emergence of cooperative relay technology effectively solves the problem of weak coverage of cell edge, improves the data transmission rate and user experience perception, and can provide a good diversity gain to a certain extent. As an advanced technology in recent years, energy collection can collect energy from the renewable resources of the surrounding environment, so as to achieve the purpose of green communication. Therefore, the combination of cooperative relay technology and energy acquisition technology is a research hotspot. In this paper, the multi-relay network with the function of energy acquisition is taken as the research object, the resource allocation algorithm in the network is analyzed, and the power allocation and relay selection of the wireless nodes in the network are emphasized. Time allocation and subcarrier pair are studied, and three resource allocation algorithms are proposed. The main contents of this paper are as follows: (1) in the two-hop multi-relay scenario, a resource allocation algorithm including power allocation and single-relay selection is proposed. The algorithm takes the joint maximum transmit power limitation and the acquisition energy independence limitation as the constraint conditions and constructs the optimization model with the objective of minimizing the outage probability of the system. The optimal transmission power of relay node is obtained by using Lagrange multiplier method and KKT condition. By calculating the contribution factor of the relay node, we select an optimal relay to participate in cooperation. In addition, the lower bound of interrupt probability is derived and the expression of the lower bound is given. Simulation results show that the proposed power allocation and single-relay selection algorithms can effectively reduce the interrupt probability of the system, and verify the correctness of the lower bound expression of the interrupt probability. (2) in the multi-relay system with energy acquisition function, An optimal time allocation algorithm based on relay selection is proposed to improve the average throughput performance of the system. Based on the limitation of energy causality and data causality, the optimization model of end-to-end throughput maximization is constructed. The branch and bound method is used to select the relay nodes used in each slot. In order to increase the amount of data received by the destination node, the simplex method and the independent solution method are used to optimize the transmission time of the source node and the relay node in each slot. The simulation results show that the proposed relay selection and time allocation algorithm can effectively improve the average throughput of the system. (3) in the energy acquisition OFDM multi-relay system, the optimization goal is to maximize the total capacity of the system. A joint power allocation and subcarrier pair optimization algorithm is proposed to improve the performance of the system. In this algorithm, the relay node adopts the energy partition structure to receive and collect the signal. Under the condition of the maximum transmit power of the source node, the channel capacity of the cooperative relay system is based on the two-hop decoding and forwarding. The optimal energy partition factor of the relay node is solved and the equivalent channel gain is derived to simplify the optimization problem. The joint optimization of subcarrier pair and node power allocation problem is carried out by using Lagrange dual programming and Hungarian algorithm. Simulation results show that the proposed resource allocation algorithm can effectively increase the average capacity of the system.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5

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