单信道全双工MAC协议研究

发布时间：2018-05-01 09:33

本文选题：无线局域网 + 全双工　；参考：《重庆大学》2016年硕士论文

【摘要】：全双工通信技术可以提高链路容量和频谱利用率,是5G和未来无线通信系统的关键技术之一。单信道全双工通信是指收发机可以在一个频带内同时接收和发送信息。随着针对全双工系统的自干扰消除(SIC)技术的不断发展,全双工通信终将得以实现。全双工技术会给现有无线局域网(WLAN)带来极大的变革,传统的半双工MAC协议已无法适应全双工WLAN,因此为了进一步提高WLAN的网络容量和频谱效率,需要研究全双工MAC协议。论文围绕单信道全双工MAC协议展开,在分析IEEE802.11标准MAC层分布式协调功能(DCF)和点协调功能(PCF)基础上,研究了单信道全双工DCF(FD-DCF)协议、全双工CSMA(FD-CSMA)协议和全双工PCF(FD-PCF)协议。具体内容和创新点如下:一、针对传统半双工DCF(HD-DCF)不适用于全双工WLAN的问题,提出一种单信道全双工DCF(FD-DCF)协议。该协议结合不同的网络场景和站点的全双工能力,对RTS/CTS帧进行合理填充,提出了四种工作模式,分别是同步全双工模式、异步全双工模式、条件半双工模式以及半双工模式,分析了FD-DCF在四种不同工作模式下的链路建立流程;结合改进马尔科夫(Markov)模型,推导了FD-DCF协议的碰撞概率、归一化饱和吞吐量、介质访问时延等指标。仿真结果显示,FD-DCF的性能比传统DCF的性能具有较大幅度的提升,特别在帧长较长、站点数较少、数据传输速率较低时,FD-DCF的吞吐量与介质访问时延的提升效果更加明显;与经典的全双工协议“ContraFlow”相比,所提协议通过牺牲极少的吞吐量和时延性能,以满足全双工网络、半双工网络以及混合双工网络的通信需求。二、针对传统CSMA机制对碰撞的感知迟缓问题,同时考虑物理层载波侦听不理想的情况,提出一种全双工CSMA(FD-CSMA)协议。该协议利用全双工技术进行不间断的载波侦听,当碰撞发生时立即停止发送数据,以此缩短对碰撞的感知时间。分析了FD-CSMA协议在干扰环境下的载波侦听和碰撞避免机制,以及在物理层载波侦听存在虚警和漏检情况下的帧传输流程。结合改进Markov模型,研究了FD-CSMA协议的归一化饱和吞吐量和介质访问时延等性能。仿真结果显示,FD-CSMA的性能比传统CSMA有明显的提升,特别在站点数较多和帧长较长的情况下,性能改善更为明显。三、针对半双工PCF(HD-PCF)协议在全双工WLAN中轮询效率不高的问题,提出一种单信道全双工PCF(FD-PCF)协议。该协议充分利用各站点的全双工能力,引入全双工轮询列表(FD-PL)结构以适应全双工网络、半双工网络和混合双工网络的应用场景,并采用集中轮询的方式分配信道的使用权。分析了FD-PCF的通信规则和帧传输流程,利用M/G/1休假队列模型分析了所提FD-PCF的介质访问时延、归一化吞吐量等性能。仿真结果显示,FD-PCF的性能比传统PCF的性能有显著提升,特别在帧长较长和包到达率较大时,系统性能改善更为显著。
[Abstract]:Full-duplex communication technology can improve link capacity and spectral efficiency. It is one of the key technologies of 5G and future wireless communication systems. Single channel full-duplex communication means that the transceiver can receive and transmit information simultaneously in a frequency band. With the development of self interference cancellation (sic) technology for full duplex system, full duplex communication will be realized. Full-duplex technology will bring great changes to the existing WLAN (WLAN). The traditional half-duplex MAC protocol can no longer adapt to the full-duplex WLAN protocol. Therefore, in order to further improve the network capacity and spectrum efficiency of WLAN, it is necessary to study the full-duplex MAC protocol. Based on the analysis of the IEEE802.11 standard MAC layer distributed coordination function and the point coordination function, this paper studies the single-channel full-duplex MAC protocol, the full-duplex CSMA-FD-CSMA-FD-CSMA protocol and the full-duplex FD-PCF protocol. The main contents and innovations are as follows: firstly, aiming at the problem that traditional half-duplex WLAN is not suitable for full-duplex WLAN, a single-channel full-duplex FD-DCF protocol is proposed. Combined with the full duplex capability of different network scenarios and sites, the protocol reasonably fills RTS/CTS frames, and proposes four working modes, namely synchronous full-duplex mode, asynchronous full-duplex mode, conditional half-duplex mode and half-duplex mode. This paper analyzes the link establishment process of FD-DCF in four different working modes, and deduces the collision probability, normalized saturation throughput and medium access delay of FD-DCF protocol combined with the improved Markov Markov model. The simulation results show that the performance of FD-DCF is much better than that of traditional DCF, especially when the frame length is longer, the number of stations is small, and the data transmission rate is low. Compared with the classical full-duplex protocol "ContraFlow", the proposed protocol can satisfy the communication requirements of full-duplex network, half-duplex network and hybrid duplex network by sacrificing minimal throughput and delay performance. Secondly, a full-duplex CSMA-FD-CSMA-CSMA protocol is proposed to solve the problem of collision perception delay in the traditional CSMA mechanism and to consider the unsatisfactory physical layer carrier detection. The protocol uses full-duplex technology for continuous carrier detection, and immediately stops sending data when the collision occurs, thus shortening the collision perception time. In this paper, the carrier detection and collision avoidance mechanism of FD-CSMA protocol in interference environment is analyzed, and the frame transmission flow in the presence of false alarm and missed detection in physical layer carrier detection is also analyzed. Based on the improved Markov model, the normalized saturation throughput and media access delay of FD-CSMA protocol are studied. The simulation results show that the performance of FD-CSMA is significantly improved than that of traditional CSMA, especially in the case of more sites and longer frame length. Thirdly, a single-channel full-duplex WLAN FD-PCF protocol is proposed to solve the problem that the half-duplex HD-PCF protocol is not efficient in full-duplex WLAN. This protocol makes full use of the full duplex capability of each station and introduces the full duplex polling list (FD-PL) structure to adapt to the application scenarios of full-duplex network, half-duplex network and hybrid duplex network, and distributes the right to use the channel by means of centralized polling. The communication rules and frame transmission flow of FD-PCF are analyzed, and the media access delay and normalized throughput of the proposed FD-PCF are analyzed by using the M/G/1 vacation queue model. The simulation results show that the performance of FD-PCF is significantly improved than that of traditional PCF, especially when the frame length is longer and the packet arrival rate is larger.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN915.04

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