基于D2D中继的TD-LTE集群系统切换机制研究
发布时间：2019-05-22 10:59
【摘要】：随着公网集群系统的进一步发展,集群用户所需的传输速率和服务质量将越来越高。传统的LTE切换技术采用硬切换技术,存在切换时延长、掉话率高和业务不稳定的问题,已无法满足集群系统的需求。在集群通信系统中,使用用户间通信(D2D)技术进行辅助切换可以提高切换过程中的传输速率、信干噪比,但建立大量的D2D连接会带来较大的时延、信令以及能量开销。此外,D2D用户复用小区频谱资源不可避免地带来干扰,如何对网络资源进行分配尽可能地减少干扰显得至关重要。在这种背景下,本文展开了对LTE集群系统切换优化机制的研究,主要包括:首先,从LTE系统切换流程和判决准则方面研究分析了其缺陷和不足,指出硬切换技术存在切换时延长和掉话率高的问题。接着,本文对学术界在集群系统切换方面的研究成果进行了总结分析,同时也分析了基于D2D中继的切换机制的优点及存在的问题。其次,参考现有文献中基于D2D的辅助切换方法,本文提出了一种基于分簇多播的公网集群系统切换方法。该方法采用基于层次分析法的簇头选择和分簇算法,将集群用户的移动性和剩余电量纳入决策因素,选择综合评价指标最高的终端作为簇头,可减少簇头的数量,并延长D2D通信的时间,实现稳定的网络分簇结构,保障集群用户在切换过程中业务的连续性和高传输速率。仿真结果表明,该优化方法能提高集群用户在切换过程中的传输速率和信干噪比,降低集群用户的能量消耗。最后,针对D2D多播复用小区频谱资源带来的干扰问题建模,本文提出了一种基于D2D多播的集群系统资源分配优化算法。此算法的优化目标是系统吞吐量最大化,将资源分配拆分为资源块分配和功率分配两步进行求解。第一步以最小化干扰为目标为多播簇寻找共享频谱的蜂窝用户,并进行资源块分配;第二步,采用遗传算法的思想搜索最优功率分配方案。之后,编写C++程序对此算法进行了仿真验证,仿真结果验证了此算法在抑制干扰、提升系统吞吐量方面的有效性。
[Abstract]:With the further development of public network cluster system, the transmission rate and quality of service required by cluster users will be higher and higher. The traditional LTE switching technology adopts hard switching technology, which has the problems of prolonged switching, high drop rate and unstable service, which can not meet the needs of cluster system. In cluster communication system, the use of inter-user communication (D2D) technology for auxiliary switching can improve the transmission rate and signal-to-noise ratio (SNR) in the switching process, but the establishment of a large number of D2D connections will bring large delay, signaling and energy overhead. In addition, D2D user reuse cell spectrum resources inevitably bring interference, how to allocate network resources to reduce interference as much as possible is very important. In this context, this paper studies the switching optimization mechanism of LTE cluster system, including: first, its defects and shortcomings are studied and analyzed from the aspects of LTE system switching process and decision criteria. It is pointed out that the hard switching technology has the problems of prolonging switching and high drop rate. Then, this paper summarizes and analyzes the research results of cluster system switching in academic circles, and also analyzes the advantages and existing problems of switching mechanism based on D2D relay. Secondly, referring to the auxiliary switching method based on D2D in the existing literature, this paper proposes a switching method of public network cluster system based on cluster multicasting. In this method, the cluster head selection and clustering algorithm based on analytic hierarchy process (AHP) is adopted, the mobility and residual electricity of cluster users are brought into the decision factors, and the terminal with the highest comprehensive evaluation index is selected as the cluster head, which can reduce the number of cluster heads. The time of D2D communication is extended, the stable network clustering structure is realized, and the service continuity and high transmission rate of cluster users in the process of switching are guaranteed. The simulation results show that the optimization method can improve the transmission rate and SNR of cluster users in the switching process, and reduce the energy consumption of cluster users. Finally, aiming at the interference problem caused by spectrum resources in D2D multicasting cells, a resource allocation optimization algorithm for cluster systems based on D2D multicasting is proposed in this paper. The optimization goal of this algorithm is to maximize the throughput of the system, and the resource allocation is divided into two steps: resource block allocation and power allocation. The first step is to find the cellular users of shared spectrum for the target of minimizing interference, and the resource block allocation is carried out. in the second step, the idea of genetic algorithm is used to search for the optimal power allocation scheme. After that, C program is written to verify the algorithm, and the simulation results verify the effectiveness of the algorithm in suppressing interference and improving the throughput of the system.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5
本文编号：2482894
[Abstract]:With the further development of public network cluster system, the transmission rate and quality of service required by cluster users will be higher and higher. The traditional LTE switching technology adopts hard switching technology, which has the problems of prolonged switching, high drop rate and unstable service, which can not meet the needs of cluster system. In cluster communication system, the use of inter-user communication (D2D) technology for auxiliary switching can improve the transmission rate and signal-to-noise ratio (SNR) in the switching process, but the establishment of a large number of D2D connections will bring large delay, signaling and energy overhead. In addition, D2D user reuse cell spectrum resources inevitably bring interference, how to allocate network resources to reduce interference as much as possible is very important. In this context, this paper studies the switching optimization mechanism of LTE cluster system, including: first, its defects and shortcomings are studied and analyzed from the aspects of LTE system switching process and decision criteria. It is pointed out that the hard switching technology has the problems of prolonging switching and high drop rate. Then, this paper summarizes and analyzes the research results of cluster system switching in academic circles, and also analyzes the advantages and existing problems of switching mechanism based on D2D relay. Secondly, referring to the auxiliary switching method based on D2D in the existing literature, this paper proposes a switching method of public network cluster system based on cluster multicasting. In this method, the cluster head selection and clustering algorithm based on analytic hierarchy process (AHP) is adopted, the mobility and residual electricity of cluster users are brought into the decision factors, and the terminal with the highest comprehensive evaluation index is selected as the cluster head, which can reduce the number of cluster heads. The time of D2D communication is extended, the stable network clustering structure is realized, and the service continuity and high transmission rate of cluster users in the process of switching are guaranteed. The simulation results show that the optimization method can improve the transmission rate and SNR of cluster users in the switching process, and reduce the energy consumption of cluster users. Finally, aiming at the interference problem caused by spectrum resources in D2D multicasting cells, a resource allocation optimization algorithm for cluster systems based on D2D multicasting is proposed in this paper. The optimization goal of this algorithm is to maximize the throughput of the system, and the resource allocation is divided into two steps: resource block allocation and power allocation. The first step is to find the cellular users of shared spectrum for the target of minimizing interference, and the resource block allocation is carried out. in the second step, the idea of genetic algorithm is used to search for the optimal power allocation scheme. After that, C program is written to verify the algorithm, and the simulation results verify the effectiveness of the algorithm in suppressing interference and improving the throughput of the system.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5
【参考文献】
相关期刊论文 前3条
1 杨文文;陈佳斌;;适合于TD-LTE公网集群系统的切换算法[J];数字通信;2014年06期
2 蒋青;蒋毅;张浩;;一种适合于第四代公网集群系统的切换算法[J];无线电通信技术;2013年06期
3 陈浩;蒋青;施意;;TD-LTE集群通信系统中基于小区筛选和AHP的切换算法研究[J];信息通信技术;2013年02期
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