Research On Multicopy Data Dissemination Mechanism In Social Delay-tolerant Network

With the popularity of smart mobile devices and the development of wireless communication technology,information exchange between mobile services become more probable and a trend.Delay-Tolerant Network is a kind of network architecture oriented to the data transmission between mobile devices,and with the prevalence of online social network,Social Delay-Tolerant Network emerges as dedicated to social communication.However,compared with traditional Internet and wireless network,Social Delay-Tolerant Network is an unstable mobile network with very limited network resource.Due to the mobility of social humans and some inherent drawbacks of wireless mobile devices,information transmission in Social Delay-Tolerant Network faces the challenges of intermittently connection,limited storage,bandwidth,energy,and unstable delay and so on.Message Replication and social metrics are the current popular data transmission mechanisms to improve network delivery ratio and reduce network overhead.In order to avoid the flooding of replication,copy quota is introduced,but how to determine an appropriate quota is still a key problem.Because of the contact characteristics of nodes,incensement of quota may not bring about improvement of delivery ratio,but waste a lot of storage and energy resource,thus reducing the efficiency of network resource.Most of the existing multi-copy mechanisms adopt static and uniform copy quota for all created messages,however,they ignore the variance of network load and heterogeneity of nodes contacts may impact the performance of copy quota.Moreover,social metrics can improve the efficiency of network delivery,but the selection of social metrics may not only impact the load distribution,but also impact the network delivery efficiency.Therefore,this paper exploits the relationship impact of copy quota on network delivery ratio and efficiency under different network load,different pairs of source and destination,and different kind of social metrics.Network delivery efficiency is denoted as copy efficiency.Based on above analysis,this paper propose an algorithm SLDR(social-awareness and load based dynamic replication)to adjust copy quota while considering the social.At the same time,this paper implements and verifies the adaption capability of SLDR to different network load.Compared to several data transmission mechanisms with static and uniform copy quota,SLDR improves network delivery ratio and copy efficiency,and relieves congestion at the same time.