蜂窝网络中D2D通信的资源分配算法研究

发布时间：2018-08-27 17:12

【摘要】：蜂窝系统中的D2D通信能够提高小区容量、降低终端用户和基站的能量损耗、提高系统的频谱利用率、减轻蜂窝基站的负担,能够在一定程度上缓解频谱资源短缺的问题。然而,D2D用户通过复用蜂窝网络的频谱资源来传输数据,不可避免地会造成蜂窝用户与D2D用户之间的干扰。因此,如何协调好蜂窝用户与D2D用户之间的资源以减少干扰是蜂窝异构网络的关键问题之一。本文主要研究了蜂窝网络系统中D2D通信的资源分配问题,分析了干扰产生的原因,同时提出干扰管理算法。具体内容如下:(1)为了提高用户选择D2D通信模式的概率,需要对D2D用户的发送功率进行优化,以保证可靠的D2D传输以及蜂窝用户的链路质量。本文提出了一种基于D2D用户功率优化的通信模式选择方法,该方法根据D2D用户和蜂窝用户与基站之间的距离比值分析用户采用D2D通信模式的条件,并通过优化用户的发送功率提高用户选择D2D通信模式的概率。仿真结果验证了用户采用D2D模式通信的条件,通过功率优化提高了用户选择D2D通信模式的概率。(2)提出了一种基于QoS的信道分配和功率控制算法。该算法首先根据D2D用户的最小SINR要求,得到D2D用户的候选蜂窝用户集;然后,在用户的QoS和发送功率受限条件下,构建了最大化D2D用户容量的目标函数。最后采用拉格朗日乘子法求解蜂窝用户和D2D用户的最优发送功率,根据最优功率计算D2D用户容量并将信道分配给容量值最大的D2D用户。然而该算法的复杂度较大,于是又提出了一种分阶段信道分配和功率控制的次优化算法。仿真结果表明,本文算法能够提高D2D用户容量,次优化算法具有近似最优化算法性能的同时也大大地降低了复杂度。(3)提出了一种基于能效的子载波分配和功率控制算法。在保证用户的QoS以及D2D用户最大发送功率约束条件下,最大化不同通信模式的D2D用户的能量效率。假设D2D用户能够选择采用模式A(直接通信)或模式B(经中继转发通信)进行通信。根据D2D用户及被其复用子载波的活跃蜂窝用户的中断概率与预设门限的关系,为D2D用户选择不同的通信模式,采用匈牙利算法为D2D用户分配子载波,采用二分算法优化D2D用户的发送功率。仿真结果表明,该算法在D2D用户容量与能量效率方面的性能更优。
[Abstract]:D2D communication in cellular system can improve the cell capacity, reduce the energy loss of end users and base stations, improve the spectrum efficiency of the system, reduce the burden of cellular base stations, and alleviate the shortage of spectrum resources to a certain extent. However, D2D users transmit data by multiplexing spectrum resources of cellular networks, which inevitably results in interference between cellular users and D2D users. Therefore, how to coordinate the resources between cellular users and D2D users to reduce interference is one of the key problems in cellular heterogeneous networks. In this paper, the resource allocation problem of D2D communication in cellular network system is studied, the reason of interference is analyzed, and an interference management algorithm is proposed. The main contents are as follows: (1) in order to improve the probability of users choosing D2D communication mode, it is necessary to optimize the transmission power of D2D users to ensure reliable D2D transmission and the link quality of cellular users. A communication mode selection method based on D2D user power optimization is proposed in this paper. According to the distance ratio between D2D user and cellular user and base station, the condition of D2D communication mode is analyzed. The probability of selecting D2D communication mode is improved by optimizing the transmission power of the user. The simulation results verify the communication conditions of users using D2D mode and improve the probability of users choosing D2D communication modes through power optimization. (2) A channel allocation and power control algorithm based on QoS is proposed. Firstly, according to the minimum SINR requirement of D2D users, the candidate cellular user set of D2D users is obtained, and then the objective function to maximize the capacity of D2D users is constructed under the condition of the user's QoS and transmission power constraints. Finally, the Lagrange multiplier method is used to solve the optimal transmission power of the cellular and D2D users. The D2D user capacity is calculated according to the optimal power and the channel is assigned to the D2D user with the largest capacity. However, the complexity of the algorithm is high, so a sub-optimization algorithm for channel allocation and power control is proposed. The simulation results show that the proposed algorithm can improve the D2D user capacity, and the sub-optimization algorithm has the performance of approximate optimization and greatly reduces the complexity. (3) A subcarrier allocation and power control algorithm based on energy efficiency is proposed. In order to maximize the energy efficiency of D2D users with different communication modes, the QoS of users and the maximum transmit power constraints of D2D users are guaranteed. Suppose D2D users can choose mode A (direct communication) or mode B (relay forward communication) to communicate. According to the relation between interrupt probability and preset threshold of D2D users and active cellular users multiplexed by them, different communication modes are selected for D2D users, and Hungarian algorithm is used to assign subcarriers to D2D users. The binary algorithm is used to optimize the transmission power of D2D users. Simulation results show that the proposed algorithm has better performance in D2D user capacity and energy efficiency.
【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

【参考文献】