支持大规模接入的WLAN技术研究与实现

发布时间：2018-03-22 10:57

本文选题：WLAN　切入点：物联网　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：当前,物联网产业发展迅速,国际上IEEE成立了专门的11ah工作组来制定相应的无线网络标准,草案版本已经公布,国内电信研究院也在联合多家单位起草相应的国内标准。物联网正发挥着不可替代的巨大作用,越来越来的智能节点以及各种各样的智能终端纷纷加入到无线局域网当中,无线局域网的容量问题受到越来越多研究者的关注。同时,受限于智能节点体积的大小以及电池技术,节点本身并不能携带大容量的电池,所以节点的节能问题是无线局域网研究的热点问题。由于物联网中智能节点的数据速率低,节点数量庞大,当前的无线局域网技术并不能直接适用于物联网,因此,需要研究面向物联网的无线局域网技术。物联网中的智能节点并不需要一直处于工作的状态,当节点无业务的时候可以让节点进入休眠状态从而节省节点的能量,本文在分析研究S-MAC协议的基础上,仿真验证了实现节点周期性的监听和休眠的S-MAC协议。物联网是大规模网络,节点数量通常在6000以上,但传统的CSMA协议的有效性会随着用户数量的增加显著降低,数据包碰撞十分明显,吞吐量急剧下降,理论上,当用户数目超过200时,站点的吞吐量趋就近于0。为支持大规模节点接入,本文提出了间隔发送同步帧机制,该机制的主要思想是控制网络中节点SYNC同步帧的发送,利用时分复用的方法,使节点分时获得信道的使用权,有效的避免了网络中数据包的冲突,提高了数据包传输的成功率。在保证吞吐量和丢包率的前提下使得网络中可以容纳的节点的数目可以达到6000个以上,同时使用对比原始的802.11MAC协议进行了仿真,验证了间隔发送同步帧机制在提升无线网络容量方面是一种十分有效的改进方法。最后,在介绍负载均衡的基础上,提出了在802.11ah Relay场景中适用的一种中继站点的选择方法,过程为:先找出只能连接一个中继站点的普通站点,并将该普通站点分配给这个中继站点,然后在多个可选的中继站点中找出能满足剩下所有普通站点的中继站点集合,在考虑负载均衡的基础上,按可选中继站点的数量从小到大排序,依次分配。通过该方法可以尽可能的减少网络中工作的中继站点的数量,节省中继站点的能耗,减少竞争次数,提高带宽的利用率。最后对发明的方法进行了仿真,验证了该方法的可行性。文中给出了所提出理论方案的分析与仿真,通过仿真验证了方案的可行性,提升了无线网络的性能。
[Abstract]:At present, with the rapid development of the Internet of things industry, the international IEEE has set up a special 11ah working group to formulate the corresponding wireless network standards. The draft version has been published. The domestic telecommunications research institute is also working together with several units to draft corresponding domestic standards. The Internet of things is playing an irreplaceable role. More and more intelligent nodes and various intelligent terminals are joining the WLAN. More and more researchers pay attention to the capacity of WLAN. At the same time, due to the size of smart nodes and battery technology, nodes themselves can not carry large capacity batteries. Because of the low data rate of intelligent nodes and the large number of nodes in the Internet of things, the current WLAN technology can not be directly applied to the Internet of things. WLAN technology for the Internet of things needs to be studied. The intelligent nodes in the Internet of things do not need to be in the working state all the time. When the nodes have no business, they can make the nodes sleep and save the energy of the nodes. Based on the analysis and research of S-MAC protocol, this paper verifies the S-MAC protocol which realizes the periodic listening and sleeping of nodes. The Internet of things is a large-scale network, and the number of nodes is usually more than 6000. However, the validity of the traditional CSMA protocol decreases significantly with the increase of the number of users, the packet collision is very obvious, and the throughput drops sharply. In theory, when the number of users exceeds 200, In order to support large-scale node access, this paper proposes a synchronous frame mechanism for interval transmission. The main idea of this mechanism is to control the transmission of SYNC synchronous frames at nodes in the network, and to use the method of time division multiplexing (TDM), the main idea of this mechanism is to control the transmission of SYNC synchronous frames in the network. The node can obtain the right to use the channel in time sharing, which effectively avoids the collision of data packets in the network. Under the premise of guaranteeing throughput and packet loss rate, the number of nodes in the network can reach more than 6000. At the same time, the simulation is carried out by comparing the original 802.11MAC protocol. It is verified that the spacer synchronous frame mechanism is an effective method to improve the capacity of wireless network. Finally, based on the introduction of load balancing, a method for selecting relay stations in 802.11ah Relay scene is proposed. The procedure is to find a common site that can only connect to one relay site, assign the normal site to the relay point, and then find a collection of relay stations that can satisfy all the remaining common sites in multiple optional relay sites. On the basis of load balancing, the number of relay stations can be arranged from small to large, which can reduce the number of relay stations working in the network as much as possible and save the energy consumption of relay stations. Finally, the method is simulated to verify the feasibility of the method. The analysis and simulation of the proposed theoretical scheme are given in this paper, and the feasibility of the scheme is verified by simulation. Improved wireless network performance.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN925.93

【相似文献】