基于OFDMA的电力线通信系统资源分配算法研究

发布时间：2018-10-20 09:14

【摘要】：随着电力线通信技术的不断发展,电力线作为一种分布最广的通信媒介,在家居自动化、远程秒表、负荷控制、宽带网络的接入和音频信号等高速数据传输等领域具有得天独厚的优势和不可估量的市场潜力。新一代宽带无线接入技术OFDMA,以其传输速率高、资源分配灵活、能同时支持多个用户的特点被成功的应用于电力线通信系统中。基于OFDMA的资源分配算法相继出现,但其在电力线通信系统中的应用研究还处于初步阶段,仍存在计算量大、不易实现的缺点,本文重点研究基于OFDMA技术的电力线通信系统资源分配问题。为提高电力线通信系统的资源利用率和服务质量,本论文在研究低压配电网电力线通信系统信道模型基础上,结合OFDMA技术的理论知识,提出一种基于改进差分进化算法的电力线通信单层多用户资源分配算法。该算法以速率自适应为准则,在功率谱限制条件下,根据各用户的信道信息进行子载波的动态分配,在保证多用户不同QoS要求的前提下最大化系统的吞吐量。在典型的电力线通信系统环境下进行了仿真实验,实验结果表明,与现有的电力线资源分配算法相比,本课题所提算法在用户公平性和系统容量上都有很大改善,有效地提高了电力线通信系统的性能。由于资源分配在电力线通信系统的不同层面具有不同的约束条件和优化目标,本论文对物理层、链路层、网络层和应用层进行了深入的研究,提出一种混合业务下的跨层资源分配算法,即在数据链路控制(MAC)层基于效用函数的用户调度算法和在物理(PHY)层基于优先级的子载波-功率联合分配方案,在提高系统利用率的同时为用户提供不同QoS等级的传输服务。在数据链路控制层,综合考虑信道状态信息、业务包模型、队列状态信息和QoS需求,确定用户的优先级;在物理层,结合速率自适应和裕度自适应准则,按照用户的优先级为各用户动态的分配子载波-功率资源。其思想是尽量减小因盲目分配而造成的资源浪费,以尽可能少的资源满足所有用户的最小速率要求,在保证用户公平性的前提下,若剩余资源能满足用户的最大许可速率,则以剩余资源的最大化为优化目标,否则,以系统吞吐量最大化为优化目标。实验结果证明,与现有的算法相比,本课题所提出的算法能够满足用用户公平性和服务质量,并且能够利用更少的资源得到更大的系统吞吐量。
[Abstract]:With the continuous development of power line communication technology, power line as the most widely distributed communication medium, in home automation, remote stopwatch, load control, Access to broadband networks and high-speed data transmission such as audio signals have unique advantages and inestimable market potential. The new generation broadband wireless access technology (OFDMA,) has been successfully applied in power line communication system because of its high transmission rate, flexible resource allocation and the ability to support multiple users simultaneously. Resource allocation algorithms based on OFDMA appear one after another, but its application research in power line communication system is still in the initial stage, and still has the shortcomings of large computation and difficult to be realized. This paper focuses on the power line communication system resource allocation based on OFDMA technology. In order to improve the resource utilization and service quality of power line communication system, this paper studies the channel model of power line communication system in low voltage distribution network, and combines the theoretical knowledge of OFDMA technology. A single layer multiuser resource allocation algorithm for power line communication based on improved differential evolution algorithm is proposed. Based on the criterion of rate adaptation, the algorithm dynamically allocates subcarriers according to the channel information of each user under the condition of power spectrum limitation, and maximizes the throughput of the system under the premise of multi-users' different QoS requirements. In the typical power line communication system, the simulation results show that compared with the existing power line resource allocation algorithm, the proposed algorithm in this paper has a great improvement in user fairness and system capacity. The performance of power line communication system is improved effectively. Because resource allocation has different constraints and optimization objectives in different layers of power line communication system, this paper makes a deep research on physical layer, link layer, network layer and application layer. A cross-layer resource allocation algorithm based on utility function in the data link control (MAC) layer and a priority-based sub-carrier power joint allocation scheme in the physical (PHY) layer are proposed. At the same time, improve the utilization of the system and provide users with different QoS levels of transmission services. In the data link control layer, the channel state information, service packet model, queue state information and QoS requirements are considered synthetically to determine the priority of the user. Subcarrier-power resources are dynamically allocated to each user according to the priority of the user. The idea is to minimize the waste of resources caused by blind allocation, to meet the minimum rate requirements of all users with as few resources as possible, and to ensure the fairness of users, if the remaining resources can satisfy the maximum permission rate of users. The optimization goal is to maximize the remaining resources, otherwise, to maximize the throughput of the system. Experimental results show that compared with the existing algorithms, the proposed algorithm can meet the user fairness and quality of service, and can use less resources to achieve greater system throughput.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN913.6;TM73

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