| With the development of wireless communication technology,the user demand of service presents a trend of diversification and the global mobile data volume presents a rapid trend of exponential growth.As one of the key technology of 5G,heterogeneous networks(HetNets)have become the solution for next generation wireless networks to improve network capacity and coverage and effectively response to the increasing data volume.As the approach to realize the cooperative transmission in HetNets,the traffic split-flow becomes the research hotspot for the next generation wireless networks.An efficient and reasonable traffic split-flow strategy is the key factor in cooperative transmission to guarantee the experience of user.This article will study the strategies and approaches of traffic split-flow in HetNets from the perspectives of centralized strategy and distributed strategy respectively,and also,a traffic split-flow platform is constructed to verify the proposed strategies.The detail of the research content is as follows:1)from the point view of centralized strategy,study the approach of traffic split-flow in LTE-WLAN HetNets.According to the proposed LTE-WLAN heterogeneous resource model and the utility function based on traffic characteristics,establishing the traffic split-flow strategy optimization model which aiming at maximizing the total utility of users.Numerical simulation indicates that compared with traditional strategy which aiming at maximizing transmission rate,the proposed strategy can allocate enough transmission resource for user which can guarantee its QoS based on the category of traffic and improve total utility by about 40%.The user fairness is also guaranteed.2)from the point view of distributed strategy,study the approach of traffic split-flow in LTE-WiMAX-WLAN HetNets.Dividing the distributed strategy problem into two level:area level and traffic level to study traffic split-flow strategy progressively.In the area-level bandwidth deployment strategy research,networks compete with each other to deploy bandwidth in each service area,aiming at maximizing network prophets based on constructing noncooperative game model.In the traffic-level traffic split-flow strategy research,based on multi-leaders and multi-followers Srackelberg game model,consider the competition and confluence relationship between the bandwidth occupation behavior of users and network pricing,and also consider the preference of different traffic to different network performance parameters,aiming at simultaneously maximizing the utility of users and networks.Numerical simulation indicates that the proposed area-level bandwidth deployment strategy can avoid the congestion of networks which having more potential user connections,while the traffic-level traffic split-flow strategy can make user get higher net utility and average match-degree simultaneously by about 70%.3)design and construct a traffic split-flow platform of LTE-WLAN heterogeneous networks,including designing the platform structure and analyzing the key technologies,and introducing the working procedure.Based on the platform,verify the match-degree self-adaptive split-flow strategy adapting to the quality of wireless link to decrease the jitter and delay of the video traffic by about 48%and 30%,respectively. |
