下一代超高速WLAN一种基于区分业务的帧聚合策略

发布时间：2018-01-22 01:53

本文关键词： 下一代超高速WLAN MAC 两级调度帧聚合 OPNET　出处：《电子科技大学》2013年硕士论文　论文类型：学位论文

【摘要】：无线局域网技术凭借其不可替代的优势，已经融入到日常生活的方方面面，2012年2月24日，中国工业与信息化部发布公告，批准《高频谱利用率和高数据吞吐的无线局域网技术要求第1部分：超高速无线局域网媒体访问控制层（MAC）和物理层（PHY）》等两项通信行业标准，即本文的主要技术研究背景：下一代超高速无线局域网技术（NUHT）。NUHT系统在频谱效率、物理层传输速率和MAC层吞吐率等性能方面都有很明显的提高，它以研制具有自主知识产权的高效中短距离通信系统为主要研究目标。该标准通过改进物理层以及MAC层接入技术，在采用感知无线电和频带聚合技术后，其最高吞吐量能够达到1.2Gbps。 NUHT系统采用的接入机制是集中调度为主、竞争接入为辅的这样一种既保证系统吞吐量又兼顾BE业务灵活性的接入机制。针对这种情况，在只考虑集中调度的接入模型下，文章提出一种区分业务的帧聚合策略，将业务QoS等级、业务平均到达率、队列时延紧迫程度等作为主要参数指标，结合排队论系统数学模型，采用非对称、队列容量有限的批量服务模型以及定额服务的方式对业务队列进行处理，最终得出每个队列的聚合权重值，聚合模块即可以按照队列的聚合权重对各业务队列进行聚合操作，其中聚合权重表示每个业务队列数据包在一次聚合帧中所占的比特百分比。这种调度和聚合模型可以优先保证QoS业务需求，同时降低了帧头、帧间间隔等一些冗余开销，仿真表明该区分业务的帧聚合模型可以优先保证高优先级业务，同时该方式比不区分业务的聚合机制以及经典的WRR算法在队列溢出率、平均队列长度等指标上都有明显优势。但是该模型在低到达率场景下性能明显比较差，针对这种情况，文章又提出一种改进放入触发机制，最后通过仿真说明该措施的有效性。最终，本文在OPNET仿真平台上搭建了下一代超高速无线局域网MAC层的简易模型，实现了MAC层业务流建立、修改、删除，，带宽申请（稍带和单独请求两种方式）功能、业务队列维护、聚合成帧、立即确认（块确认和单帧确认）、自动重传、分片和重组等基本功能，并在此平台上验证了区分业务队列的帧聚合策略的有效性。
[Abstract]:With its irreplaceable advantages, WLAN technology has been integrated into all aspects of daily life. In February 24th 2012, the Ministry of Industry and Information issued a notice. Approval of the Technical requirements for Wireless Local area Networks (WLAN) with High Spectral efficiency and High data throughput part 1: two communications industry standards: media access Control layer (MAC) and physical layer (PHY) for Ultra High Speed Wireless Local area Networks (WLAN). That is the main technical background of this paper: the next generation of ultra-high speed wireless local area network (WLAN) technology in the NUHT.NUHT system spectrum efficiency. Physical layer transmission rate and MAC layer throughput have been significantly improved. It aims to develop an efficient medium and short range communication system with independent intellectual property rights. This standard improves physical layer and MAC layer access technology, after adopting perceptual radio and frequency band aggregation technology. Its maximum throughput can reach 1.2 Gbps. The access mechanism used in NUHT system is centralized scheduling, supplemented by competitive access, which not only ensures the throughput of the system but also takes into account the flexibility of be services. Under the access model which only considers centralized scheduling, this paper proposes a frame aggregation strategy for traffic differentiation, which takes the QoS level of services, the average arrival rate of traffic, and the urgency of queue delay as the main parameters. Combined with the mathematical model of queuing theory, the batch service model with asymmetric, limited queue capacity and quota service are used to deal with the business queue. Finally, the aggregate weight of each queue is obtained. The aggregation module can aggregate each business queue according to the aggregation weight of the queue. The aggregation weight represents the bit percentage of each service queue packet in an aggregated frame. This scheduling and aggregation model can first guarantee the QoS traffic requirements while reducing the frame header. Some redundant overhead such as inter-frame interval, simulation shows that the frame aggregation model of differentiated services can give priority to high-priority services. At the same time, this method is better than the aggregation mechanism which does not distinguish traffic and the classical WRR algorithm in queue overflow rate. The average queue length has obvious advantages, but the performance of the model is obviously poor in the low arrival rate scenario. In view of this situation, this paper proposes an improved trigger mechanism. Finally, the effectiveness of the measure is demonstrated by simulation. Finally, this paper builds a simple model of the next generation ultra-high speed WLAN MAC layer on the OPNET simulation platform, and realizes the establishment, modification and deletion of MAC layer traffic. Bandwidth request (both slightly and individually requested) functions, service queue maintenance, aggregation into frames, immediate confirmation (block confirmation and single frame confirmation, automatic retransmission, slicing and reorganizing, and other basic functions). The effectiveness of the frame aggregation strategy is verified on this platform.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TN925.93

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