高铁场景下基于移动中继的越区切换和子载波资源分配的研究

发布时间：2018-04-17 17:13

本文选题：高速铁路 + 移动中继　；参考：《北京交通大学》2017年硕士论文

【摘要】：伴随着近年来通信技术的飞速发展,用户对于无线通信质量和无线数据业务QoS的要求也逐渐提高。然而在高速移动的铁路场景下,乘客在享受着高铁列车带来便捷的同时也不得不面对高铁列车密闭车厢引起的严重的穿透损耗,越区切换成功率下降和车内用户与小区用户之间资源调度不平衡等诸多问题,这些问题都会对高铁列车内用户的通信质量造成非常大的影响。为了解决上述高铁环境下车载用户面临的问题,本文考虑将传统公共蜂窝网络中的固定中继技术应用到高铁列车中作为车载移动中继应用,并针对上述问题进行具体的研究与分析。本文的研究将建立在基于车载移动中继的高速铁路通信网络场景下,针对基于车载移动中继用户越区切换性能,基于中继的资源调度方案和AF类型中继两跳之间的子载波匹配和子载波功率分配问题进行分析与仿真对比。本文将基于高速铁路场景,明确车载用户的越区切换性能指标,并通过仿真对比验证车载移动中继的引入对列车用户越区切换性能起到的增益作用。针对列车频繁穿越小区,打破原小区用户的调度平衡的现象,本文提出一种基于中继的双队列调度方案。通过协调基站与车载中继的资源调度分工,实现资源的二次分配,可以有效地兼顾原小区用户与车载用户的资源调度,提高车载用户系统的系统性能。最终通过仿真证明提出的调度方案可以有效提升车内系统的系统容量。车载移动中继的引入会将原有的基站与车载用户之间的直连链路分割为回程链路与接入链路两跳。对于LTE-A系统,需要针对两跳之间的子载波匹配和子载波的功率分配问题进行合理的优化以达到最佳的系统容量。本文通过将子载波匹配和子载波功率分配工作分开进行来降低整个优化过程的复杂度。在子载波匹配阶段依据贪婪思想的子载波增益顺序原则对两跳间子载波进行匹配;在子载波对完成匹配的基础上,将高速铁路场景信道时变的影响考虑进来作为限制条件构建优化问题并求解最佳的功率分配结果,从而达到最大化系统容量的目的,最后通过仿真验证子载波匹配和功率分配优化对系统容量的提升作用。
[Abstract]:With the rapid development of communication technology in recent years, users' requirements for wireless communication quality and wireless data service QoS are gradually improved.However, in the high-speed moving railway scene, while enjoying the convenience brought by high-speed trains, passengers also have to face the serious penetration losses caused by the airtight carriages of high-speed trains.There are many problems such as the decrease of the success rate of handoff and the imbalance of resource scheduling between the users in the vehicle and the users in the district. These problems will have a great impact on the communication quality of the users in the high-speed train.In order to solve the problems faced by the onboard users in the high-speed railway environment, this paper considers the application of fixed relay technology in the traditional public cellular network to the high-speed rail train as the on-board mobile relay application.And in view of the above question carries on the concrete research and the analysis.The research of this paper will be based on the high-speed railway communication network scenario based on vehicle-mounted mobile relay, aiming at the handoff performance of vehicle-mounted mobile relay users.The resource scheduling scheme based on relay and the sub-carrier matching and sub-carrier power allocation between AF type relay and two hops are analyzed and simulated.Based on the scene of high-speed railway, this paper makes clear the performance index of on-board users' handoff, and verifies the gain effect of the introduction of on-board mobile relay on the handoff performance of train users through simulation.In view of the phenomenon that trains frequently cross the cell and break the balance of users' scheduling in the original cell, a dual queue scheduling scheme based on relay is proposed in this paper.By coordinating the division of resources between the base station and the on-board relay and realizing the secondary allocation of resources, the system performance of the system can be improved by taking account of the resource scheduling of the original users and the on-board users.Finally, the simulation results show that the proposed scheduling scheme can effectively improve the system capacity.The introduction of vehicular mobile relay will divide the direct link between the base station and the on-board user into two hops: backhaul link and access link.For LTE-A system, it is necessary to optimize the sub-carrier matching and power allocation between two hops to achieve the optimal system capacity.In this paper, subcarrier matching and subcarrier power allocation are separated to reduce the complexity of the optimization process.In the phase of subcarrier matching, the subcarrier matching between two hops is carried out according to the greedy subcarrier gain sequence principle, and on the basis of the matching of subcarrier pairs,The time-varying influence of the scene channel of high-speed railway is taken into account as a limiting condition to construct the optimization problem and to solve the optimal power allocation result so as to maximize the system capacity.Finally, the effect of subcarrier matching and power allocation optimization on the system capacity is verified by simulation.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5

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