基于LTE的卫星移动通信系统无线资源调度技术研究

发布时间：2018-08-26 18:51

【摘要】：基于LTE(Long Term Evolution)的卫星移动通信系统将LTE标准和技术引入到卫星通信中,能有效利用LTE系统技术成熟、速率高、成本低和卫星通信覆盖范围广、抗毁性强等优势,在实现全球高速移动通信方面受到了世界各国的广泛重视。然而,与地面移动通信所处的无线链路环境不同,星地链路存在的长传输时延、高误码率和上下行带宽非对称等问题,对基于LTE的卫星移动通信系统中的无线资源调度提出了极大挑战。本文对基于LTE的卫星移动通信系统中的无线资源调度技术进行了深入研究,主要工作如下:第一、对基于LTE的卫星移动通信系统中语音业务的资源调度进行了研究。在对现有半持续调度(Semi-Persistent Scheduling,SPS)进行优化的基础上,提出了一种面向语音业务的半持续调度方法Vo SPS(Voice services oriented Semi-Persistent Scheduling approach)。针对用户信道质量恶化时的上行资源浪费问题,Vo SPS中增加了一种基于上行信道质量的准入与截断机制UACM(Uplink channel quality based Admission and Cut-off Mechanism)。为了充分利用系统上行资源,增加语音业务容量,Vo SPS中引入了一种基于语音服务满意度的编码速率调整算法SCRA(voice service Satisfaction based Code Rate Adjustment algorithm)。仿真结果表明,Vo SPS能有效地提高系统的用户满意度,增加系统的语音业务容量。第二、对基于LTE的卫星移动通信系统的上行资源调度进行研究,提出了一种基于缓存状态预测的调度方法BSP(Buffer Status Prediction based scheduling approach)。BSP包括缓存状态预测上报机制BSPR(Buffer Status Prediction and Reporting mechanism)和基于缓存状态的比例公平调度算法BSPF(Buffer Status based Proportional Fairness scheduling algorithm)。针对星地链路传输时延远长于LTE资源调度周期的问题,BSPR机制根据上行业务的流量特性,对用户设备(User Equipment,UE)的缓存状态进行预测上报,使演进型基站(evolved Node B,e NB)能够更加合理地分配无线资源。BSPF调度算法在现有比例公平(Proportional Fairness,PF)调度算法的基础上,增加UE的缓存状态作为调度判决参数,考虑了业务的服务质量(Quality of Service,Qo S)等级和数据流量大小。仿真结果表明,BSP调度方法能够有效地提高系统的资源利用率,更好地满足具有高Qo S等级和大数据流量业务的吞吐量需求。
[Abstract]:The satellite mobile communication system based on LTE (Long Term Evolution) introduces the LTE standard and technology into the satellite communication, which can effectively utilize the advantages of the LTE system technology maturity, high speed, low cost, wide coverage of satellite communication, strong invulnerability and so on. In the realization of global high-speed mobile communication has been widely paid attention to all over the world. However, different from the wireless link environment of terrestrial mobile communication, there are many problems such as long transmission delay, high bit error rate and asymmetric uplink and downlink bandwidth. This paper presents a great challenge to wireless resource scheduling in satellite mobile communication systems based on LTE. In this paper, the wireless resource scheduling technology in the satellite mobile communication system based on LTE is deeply studied. The main work is as follows: first, the resource scheduling of voice services in the satellite mobile communication system based on LTE is studied. Based on the optimization of the existing semi-persistent scheduling (Semi-Persistent Scheduling,SPS), a speech service-oriented semi-persistent scheduling method, Vo SPS (Voice services oriented Semi-Persistent Scheduling approach)., is proposed. In order to solve the problem of uplink resource waste when user channel quality is deteriorating, a new access and truncation mechanism UACM (Uplink channel quality based Admission and Cut-off Mechanism). Based on uplink channel quality is added to Vo SPS. In order to make full use of the uplink resources of the system, a coding rate adjustment algorithm SCRA (voice service Satisfaction based Code Rate Adjustment algorithm). Based on voice service satisfaction is introduced into Vo SPS to increase voice service capacity. The simulation results show that Vo SPS can effectively improve the user satisfaction of the system and increase the voice service capacity of the system. Secondly, the uplink resource scheduling of satellite mobile communication system based on LTE is studied. A scheduling method based on cache state prediction (BSP (Buffer Status Prediction based scheduling approach). BSP) is proposed in this paper, which includes cache state prediction and report mechanism (BSPR (Buffer Status Prediction and Reporting mechanism) and proportional fair scheduling algorithm (BSPF (Buffer Status based Proportional Fairness scheduling algorithm).) based on cache state. In order to solve the problem that the delay of satellite-ground link transmission is longer than that of LTE resource scheduling period, the mechanism predicts and reports the buffer state of user equipment (User Equipment,UE) according to the traffic characteristics of uplink services. So that the evolutionary base station (evolved Node be NB can allocate the wireless resource more reasonably. On the basis of the existing proportional fairness (Proportional Fairness,PF) scheduling algorithm, the buffer state of UE is added as the scheduling decision parameter. Quality of Service (Quality of Service,Qo S) and data traffic are considered. The simulation results show that the scheduling method can effectively improve the resource utilization of the system and better meet the throughput requirements of high Qo S level and big data traffic services.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN927.23

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