Research AP Selection Mechanism Based On SDWN

With the continuous development of the society,the number of mobile terminals is increasing explosively,and Wireless Local Area Networks(WLAN)has the advantages of flexible deployment and extensibility,which has attracted wide attention from the industry.At present,traditional WLAN has disadvantages in access selection mechanism and load balancing.First,the terminal uses a traditional algorithm based on received signal strength indication to access specific APs.It is easy to cause load imbalance and waste network resources,which can not meet users' needs well.It does not also meet user requirements very well.Secondly,the terminal switches between APs are mostly hard-switched and will be disconnected for a short period of time,which will have a greater impact on user service quality.The emergence of new network architectures such as software defined network(SDN)has the advantages of flexibility,programmability,and scalability.It can provides a new direction for traditional WLANs in access selection mechanisms and load balancing.In the software defined wireless network(SDWN)architecture,Odin is an SDWN architecture proposed for enterprise WLANs.It has features such as compactness,open source,and flexibility,which facilitates the addition of load balancing function module for WLANs.In view of the shortcomings of traditional WLAN access mechanism and load balancing,this paper proposes a seamless handoff scheme between AP based on traffic load perception based on SDWN architecture.This scheme takes account of the received signal strength(RSSI)and traffic load on the AP,and can completes load balancing and seamless handover between terminals in AP overlap area.In order to better guarantee the quality of terminal service,a terminal multi-point association scheme is proposed.Using the network virtualization technology,the relationship between the terminal and the physical AP is changed,and the hard handover problem in the traditional WLAN is solved.The main research work conducted in this paper is summarized as follows:(1)Researching SDN architecture,SDWN architecture,load balancing technology and AP virtualization technology.The emphasis is on the advantages of the SDWN architecture,such as load balancing technology and AP virtualization technology,which provides a theoretical basis for the seamless handoff scheme.(2)As the traditional network architecture is rigid and the network equipment is bloated,APs with better performance cannot be selected in the AP overlap area.This paper comprehensively considers the influence of the traffic load on the AP and the received signal strength indication between the terminal and the AP on the performance of the AP under the SDWN architecture.A seamless handoff scheme between AP based on traffic load perception in SDWN with network virtualization technology is proposed.Finally,through the seamless migration of lightweight virtual access point,the purpose of improving terminal service quality is achieved.(3)In order to solve the problem of unbalanced load in existing WLAN and handover problem caused by the hard association between mobile terminal and AP,this paper proposes a terminal multi-point association scheme based on SDWN.This scheme improves the seamless handoff algorithm between AP based on traffic load perception.When sensing AP load,the terminal can connect multiple virtual APs to achieve dynamic diversion.(4)To verify the feasibility and effectiveness of the proposed scheme,the New Odin master module,the New Odin agent module,the load balancing module,and the subscriptionAP-status frame and new-AP-status are added on the basis of the traditional Odin architecture.The Odin architecture was verified on the laboratory equipment.The experiment shows that the seamless handoff algorithm between APs based on traffic load perception in SDWN improves the network throughput of the terminal compared with the traditional handover algorithm,and can effectively solve the problem of load imbalance between AP.Based on the above research,the terminal multi-point association scheme based on SDWN changes the relationship between the terminal and the AP one by one compared to seamlessly switching to another AP,which effectively improves the terminal network throughput.