Research On ICN-based Routing Mechanisms For Mobile Social Network

Nowadays,intelligent portable mobile devices are acting irreplaceable roles in people's daily life.As the holders of these devices,users themselves possess social attributes and they have social relationships among each other.Besides,with the rapid development of new technologies of wireless network(e.g.5G),powerful supports are provided for the commu-nications among mobile users.Mobile users interconnect with each other based on wireless network and share information via Online Social Network(OSN)applications(e.g.,Facebook and WeChat),and that constitutes the traditional Mobile Social Network(MSN).Simultane-ously,with the development of technologies of short-distance communications(e.g.,bluetooth),MSN users can share data(e.g.,multi-media)by forwarding messages among their mobile devices when they are in the communication range of each other,thus to reduce the occupancy bandwidth of network and economize their financial consumption.In that way,MSN can be defined as a Delay Tolerant Network(DTN)which is comprised of mobile nodes with social characteristics.At present,the research foci in MSN include mobile crowdsourcing,influence maximi-zation,social recommendation,privacy protection and routing,etc.To satisfy the daily in-creasing content requests of MSN users,data sharing should be realized through message transmission among mobile devices.In this process,routing plays a necessary role,thus MSN routing is significantly crucial.However,MSN routing is facing serious challenges,e.g.,it is difficult to obtain the exact social relationships of mobile users(e.g.,interest similarities)and accommodate itself to the condition of the unknown addresses of destination nodes(e.g.,to achieve an effective resolution of the addresses of destination nodes in a distributed environ-ment),as well as the delivery delay and the delivery ratio of messages are unsatisfactory,etc.Due to the fact that the existing paradigm of MSN is hard to overcome the above difficulties,a new MSN system can be introduced to simplify these problems.Information-Centric Networking(ICN)is a content-oriented new type of network.It represents the interest of user as content name and conducts routing based on these names,based on which routing schemes can easily obtain the interest preferences of users and pre-cisely describe their interest similarity by analysis.Besides,ICN does not depend on the ad-dresses of nodes because it adopts the position-independent naming principle and concerns about "what is the content" rather than "where is the content".Therefore,it can accommodate itself to the condition of the unknown destination addresses of nodes.In addition,ICN supports in-network caching,which makes interest requests independent of the original content provider and responded by the neighbor that caches the content,thus to improve the delivery ratio and delay of message.Finally,since ICN naturally supports the content mobility,it lays the foun-dation of its integration with MSN.To sum up,incorporating the content oriented routing paradigm of ICN,this dissertation has investigated the ICN based MSN routing mechanism,and major innovations and contributions are summarized as follows.(1)The archetype of ICN based MSN routing mechanism is proposed,and the routing is divided into three major modules:interest packet routing,data packet routing and in-network caching of the content.Firstly,according to the naming principle of content in ICN,the interest requests of users are expressed by the content names.In order to retrive the content provider,the interest metrics of users are obtained by analyzing their historical requested content names,and the interest packet routing scheme is proposed based on these interest metrics.Then,in order to return the content back to the interest requester,the data packet routing scheme is proposed based on the closeness,which is obtained by analyzing the historical encounter in-formation among nodes.Meanwhile,different from the traditional data delivery mode which routes data packet along the original path of its corresponding interest packet,data packets are rerouted to adapt to the MSN mobility.Next,in order to guarantee the highest probability to return the content back to the interest requester and be requested again,the in-network caching scheme is proposed based on the friendship metric,which are calculated based on the proposed closeness and interest metrics among nodes.What's more,the time complexity of the integral routing mechanism is analyzed and the lower bound of the unit content caching time period is evaluated,which provide the feasibility and effectiveness of the proposed scheme.Finally,the experimental results demonstrate that the proposed mechanism can satisfy the content request of users effectively.It increses about 21%of the packet delivery ratio and decresces about 56%of the delivery delay compared to the benchmark.(2)Since the community detection technology can improve the MSN routing efficiency effectively,the community detection is leveraged in the ICN based MSN routing archetype and the ICN based community-aware MSN routing scheme is proposed.Firstly,the interest packet routing scheme is proposed based on the interest communities,which are divided according to the proposed content interest metric,direct interest friends and indirect interest friends.Sec-ondly,the data packet routing scheme is proposed based on the social communities,which are divided according to the proposed encounter density,strong-tie friends and weak-tie friends.Thirdly,in order to optimally manage the content caching space,a content in-network caching scheme is proposed according to both the interest communities and social communities.Next,the proposed in-network caching scheme has been proved has the optimal content cache ability,which can enable nodes to respond the requested content with the highest probability.Finally,the experimental results demonstrate that the proposed mechanism can provide content for the user effectively.It increses about 38%of the packet delivery ratio and decresces about 41%of the delivery delay compared to the benchmark,which is a single community structure based routing scheme.(3)Aiming at the dead end issue of message forwarding in MSN,an ICN based dead end avoidance MSN routing scheme is proposed.Firstly,in order to solve the local optimum brought by the greedy forwarding principle,that is,forwarding the message to the node with higher social position,a backtracking based dead end avoidance strategy is proposed.Secondly,intergrating with the dead end avoidance strategy,and based on the interest distance metric and encounter regularity respectively,the dead end avoidance interest packet routing scheme and data packet routing scheme are proposed,thus to avoid interest packets and data packets get stuck into the dead ends.Thirdly,to satisfy the content requests of the community members with highest probability,the in-network caching is proposed based on the community interest preferance.Finally,the experimental results demonstrate that the proposed routing schem can improve the performance of the ICN based MSN routing scheme.It increses about 51%of the packet delivery ratio and decresces about 46%of the delivery delay compared to the bench-mark,which does not consider the dead end.(4)Oriented to a typical use case of MSN,i.e.,Vehicular Social Network(VSN),an ICN based routing scheme in the fixed-line VSN is proposed to satisfy the content request of fixed-line transportation passengers.Firstly,based on a real human social regularity,a social backlog management scheme is proposed to effectively manage the messages(including in-terest packets and data packets)stored in the backlogs of vehicle nodes and decide the for-warding sequence of the messages when nodes have forwarding opportunities.Secondly,considering the different processing sequences of messages,a bilateral forwarder determina-tion scheme is proposed,in which the delivery ability of the candidate forwarding node and the forwarding sequence for the message calculated by the candidate forwarding node are con-sidered,thus to make the message obtain the priority processing by the forwarding node and achieve its fast delivery.Thirdly,intergrating with the link expired time,the interest packet routing scheme and the data packet routing scheme are proposed,thus to adapt the fast movement of vehicle nodes in VSN and increase the probability of successful data transmis-sion.Finally,the experimental results demonstrate that the proposed routing scheme can satisfy the content request of fixed-line passengers.It increses about 57%of the packet delivery ratio and decresces about 13%of the delivery delay compared to the classical VSN routing scheme.In summary,this dissertation integrates ICN paradigm into MSN and devises four ICN based MSN routing mechanisms by introducing community detection and social metrics,such as contribution,closeness and interest similariy.In addition,they are simulated over real da-tasets and synthetic network topologies with evaluating some important performance metrics,such as packet delivery ratio,average delivery hop,average delivery delay and network overhead.The comprehensive results have strong theoretical value and practical significance,which further provides a new perspective idea for designing the valuable MSN routing mechanism.