软件定义无线网络中双网络通道互备无线接入点切换方案  

Dual-NIC Mutual Backup Scheme for Access Point Handoff in Software Defined Wireless Networks

作　　者：彭大川 杨喜敏[1] 唐菀[1] 张潇[1] 范垒 PENG Da-chuan;YANG Xi-min;TANG Wan;ZHANG Xiao;FAN Lei(Department of Computer Science,South-Central University for Nationalities,Wuhan 430074,China)

机构地区：[1]中南民族大学计算机科学学院,武汉430074

出　　处：《计算机科学》2021年第S01期427-431,437,共6页Computer Science

基　　金：国家自然科学基金项目(61902437)。

摘　　要：软件定义无线网络(Software Defined Wireless Network,SDWN)中,终端在无线接入点(Access Point,AP)切换时容易造成网络中断以及待切换无线接入点选择不当等问题,从而导致实时应用服务质量下降。为了解决这一问题,文中提出了一种基于双网络通道互备的AP切换方案。该方案首先利用双网络通道互备机制在链路层实现先连后断的软切换,并进一步利用SDWN中网络地址映射机制实现网络层的无缝切换。依据基于综合评价法(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)的思想,设计实现了高性能AP选择算法。该算法中根据待切换AP的信号强度、负载、传输带宽和当前连接数构造待评价对象,并依据待评价对象与理想对象的接近程度进行待切换AP选择。通过NS-3网络模拟器仿真实验表明:相较于基于RSSI的切换方案,所提方案中实时应用的传输时延降低了85.29%,丢包率降低了14.11%,吞吐量提升了8.94%。提出的双网络通道切换方案能够明显改善单网络通道切换方案因AP切换造成的网络中断问题,更好地保障实时应用的服务质量。In the software defined wireless network(SDWN),mobile terminal are likely to cause network interruption and improper selection of awaiting switched wireless access point(AP)during the handoff process,which may result in a significant decrease in real-time application service quality.In order to address this issue,this paper proposes an AP handoff scheme based on dual network interface controller(NIC)mutual backup.This scheme uses the dual-NIC mutual backup mechanism to realize the soft handoff at link layer.The mobile terminal can associate with the new AP first and then disassociate from the old AP.Further,the network address translation(NAT)mechanism is adopted in SDWN to realize seamless handoff at network layer.Inspired by the technique for order preference by similarity to an ideal solution(TOPSISI),the proposed AP selection algorithm constructs the candidate object to be evaluated according to the signal strength,load,transmission bandwidth and the current connections numbers of candidate APs.The AP selection are made based on the calculated closeness between the object to be evaluated and the ideal object.Finally,the experiments are conducted on NS-3.The results show that compared with the RSSI based handoff scheme,the transmission delay and the packet loss rate of the proposed scheme are reduced by 85.29%and 14.11%respectively,and the throughput is increased by 8.94%.The proposed dual-NIC mutual backup handoff scheme can significantly improve the problem of network interruption caused by AP handoff in the single-NIC handoff scheme,and better guarantee the service quality of real-time applications.

关 键 词：软件定义无线网络 双网络通道 无线接入点切换 软切换 TOPSIS 

分 类 号：TP393.0[自动化与计算机技术—计算机应用技术] TN929.5[自动化与计算机技术—计算机科学与技术]