异构无线网络中基于协作通信的链路质量提升技术研究
发布时间：2018-10-05 19:50
【摘要】：近年来,随着无线通信技术的不断进步与发展,移动数据业务迅速普及。有数据显示超过60%的话音业务和80%的数据流量业务都发生在室内场所,而传统的Macrocell网络虽然具有覆盖范围比较大的优势,但是却在室内场所等热点区域覆盖问题上具有明显的不足。异构网络正是针对上述问题从网络架构方面提出的解决方案,通过引入Femtocell较好地提升了室内用户的服务质量和频谱资源利用率,但同时也产生了层间干扰和频繁越区切换等问题,而这将会导致较高的系统掉话率,严重干扰Macrocell用户(MUE)的正常通信。为此,本文采用协作通信技术寻求上述问题的解决方案,提升MUE上下行链路的通信质量。论文主要研究内容如下:首先,对Femtocell的引入原因和发展历程进行简单的阐述,并着重分析用户接入Femtocell接入点(FAP)的三种接入模式和部署Femtocell的重要性;对放大转发(AF)和译码转发(DF)两种协议通信协作进行详细的分析比较,并从仿真结果得出DF协议的中断概率性能优于AF协议;同时,构建Femtocell/Macrocell双层异构网络上下行链路的系统模型,在该模型的基础上分析MUE上下行链路。然后,对异构网络MUE的下行链路进行了研究。下行链路协作通常采用基站间协作方式,需要大量的共享信息,为避免这一问题,本文选用Femtocell用户(FUE)作为中继节点,提出了宏基站(MBS)与FUE的协作通信方式。同时,为了选择出合适的中继节点,提出了一种协作FUE的选择算法。该算法借鉴了软切换的思想,通过引入持续时间和设置信噪比门限值选择合适中继构建中继集合:中继候选集和中继入选集,继而获得性能稳定且对MUE有益的中继集合。理论分析和仿真结果表明基于FUE的协作方案确实提升了MUE下行链路误比特率和系统吞吐量性能。最后,对异构网络MUE的上行链路进行了研究。由于边缘MUE与MBS之间路径损耗比较严重,导致边缘MUE与MBS间的通信链路经常中断,为解决这一问题,本文选择FAP充当中继节点,提出MUE与FAP的协作方案,并分析了DF和直接转发两种转发方式下MUE性能。同时,在DF方式下还分析了两种情形:一种是考虑FUE空闲;另一种则考虑FUE也在通信,然后对MUE上行链路性能进行仿真实现,其结果表明采用FAP协作方案的MUE上行链路中断概率和误比特率性能要明显优于直接传输。
[Abstract]:In recent years, with the continuous progress and development of wireless communication technology, mobile data services are rapidly popularized. Some data show that more than 60% of voice services and 80% of data traffic occur in indoor places, while the traditional Macrocell network has the advantage of large coverage. However, there are obvious deficiencies in the coverage of hot spots such as indoor places. Isomeric network is to solve the above problems from the aspect of network architecture, through the introduction of Femtocell to improve the quality of service and spectrum resource utilization of indoor users. However, there are also some problems such as interlayer interference and frequent handoff, which will lead to a higher system drop rate and seriously interfere with the normal communication of Macrocell user (MUE). In order to improve the communication quality of MUE uplink and downlink, this paper uses cooperative communication technology to find solutions to the above problems. The main contents of this paper are as follows: firstly, the introduction reason and development course of Femtocell are briefly described, and the importance of three access modes of (FAP) and the importance of deploying Femtocell are analyzed. The communication cooperation between amplifying and forwarding (AF) and decoding forwarding (DF) is analyzed and compared in detail. From the simulation results, the outage probability performance of DF protocol is better than that of AF protocol, and the system model of Femtocell/Macrocell double-layer heterogeneous network is constructed. Based on this model, MUE uplink and downlink are analyzed. Then, the downlink of heterogeneous network MUE is studied. In order to avoid this problem, the Femtocell user (FUE) is chosen as the relay node, and a cooperative communication mode between (MBS) and FUE is proposed in this paper. At the same time, in order to select the appropriate relay nodes, a cooperative FUE selection algorithm is proposed. The algorithm draws lessons from the idea of soft handoff and selects the appropriate relay set by introducing duration and setting SNR threshold: relay candidate set and relay selected set, and then obtains the relay set which is stable in performance and beneficial to MUE. Theoretical analysis and simulation results show that the cooperative scheme based on FUE can improve the bit error rate (BER) and system throughput performance of MUE downlink. Finally, the uplink of heterogeneous network MUE is studied. Because of the serious path loss between the edge MUE and the MBS, the communication link between the edge MUE and the MBS is often interrupted. In order to solve this problem, this paper chooses FAP as the relay node and proposes a cooperative scheme between MUE and FAP. The performance of MUE under DF and direct forwarding is analyzed. At the same time, two cases are analyzed in DF mode: one is to consider FUE idle, the other is to consider that FUE is also communicating, and then emulate the performance of MUE uplink. The results show that the outage probability and bit error rate (BER) performance of MUE uplink using FAP cooperative scheme is better than that of direct transmission.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5
本文编号：2254656
[Abstract]:In recent years, with the continuous progress and development of wireless communication technology, mobile data services are rapidly popularized. Some data show that more than 60% of voice services and 80% of data traffic occur in indoor places, while the traditional Macrocell network has the advantage of large coverage. However, there are obvious deficiencies in the coverage of hot spots such as indoor places. Isomeric network is to solve the above problems from the aspect of network architecture, through the introduction of Femtocell to improve the quality of service and spectrum resource utilization of indoor users. However, there are also some problems such as interlayer interference and frequent handoff, which will lead to a higher system drop rate and seriously interfere with the normal communication of Macrocell user (MUE). In order to improve the communication quality of MUE uplink and downlink, this paper uses cooperative communication technology to find solutions to the above problems. The main contents of this paper are as follows: firstly, the introduction reason and development course of Femtocell are briefly described, and the importance of three access modes of (FAP) and the importance of deploying Femtocell are analyzed. The communication cooperation between amplifying and forwarding (AF) and decoding forwarding (DF) is analyzed and compared in detail. From the simulation results, the outage probability performance of DF protocol is better than that of AF protocol, and the system model of Femtocell/Macrocell double-layer heterogeneous network is constructed. Based on this model, MUE uplink and downlink are analyzed. Then, the downlink of heterogeneous network MUE is studied. In order to avoid this problem, the Femtocell user (FUE) is chosen as the relay node, and a cooperative communication mode between (MBS) and FUE is proposed in this paper. At the same time, in order to select the appropriate relay nodes, a cooperative FUE selection algorithm is proposed. The algorithm draws lessons from the idea of soft handoff and selects the appropriate relay set by introducing duration and setting SNR threshold: relay candidate set and relay selected set, and then obtains the relay set which is stable in performance and beneficial to MUE. Theoretical analysis and simulation results show that the cooperative scheme based on FUE can improve the bit error rate (BER) and system throughput performance of MUE downlink. Finally, the uplink of heterogeneous network MUE is studied. Because of the serious path loss between the edge MUE and the MBS, the communication link between the edge MUE and the MBS is often interrupted. In order to solve this problem, this paper chooses FAP as the relay node and proposes a cooperative scheme between MUE and FAP. The performance of MUE under DF and direct forwarding is analyzed. At the same time, two cases are analyzed in DF mode: one is to consider FUE idle, the other is to consider that FUE is also communicating, and then emulate the performance of MUE uplink. The results show that the outage probability and bit error rate (BER) performance of MUE uplink using FAP cooperative scheme is better than that of direct transmission.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5
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