Research On Data Distribution And Optimization Based On Opportunistic Routing

With the popularity of smart mobile devices,we are increasingly relying on the cellular networks,which put a big burden on the already overloaded cellular network.To deal with the explosive traffic demands problem,opportunistic traffic,as a promising solution has been proposed recently to offload the traffic originally transmitted through cellular network to opportunistic networks,where large amount of resource is idle for most of the time.Currently,research on this field mainly focus on the selection of seed nodes.It is the key technique and research topic to select a subset of seed nodes to assist traffic offloading.In this paper,we focus on how to select a subset of seed nodes to assist traffic offloading,and how to efficiently deliver the requested data to subscribing nodes.Specifically,we mainly focus on two algorithms in our paper.The first is the portfolio optimization based seed nodes selection algorithm.Considering that the seed nodes selected with the highest transmission ability are not necessarily appropriate for practical use,we introduce portfolio optimization,which is widely used in economic field,to quantify the risk in traffic offloading to avoid the risk.Specifically,we select multiple set of seed nodes,and allocate different weight for them.Each time when there is a mission to offload traffic,we randomly select one seed set proportional to their weight.We formulate the problem as a complex linear programming problem,and propose a MW based algorithm to calculate a portfolio over multiple seed sets.The second is coalition formation game theory based topology control and resource allocation algorithm.Considering the long distance between seed node and subscribing node,one-hop delivery is not available.In addition,relay assisted delivery would increase the latency.We introduce network coding technique to traffic offloading.Specifically,we form “X” topology,which involves one relay and two transmission pairs to decrease the latency.We formulate the topology formation problem as a function on network throughput under transmission pair matching and relay selection.We adopt coalition game theory to jointly match devices to form transmission pairs and select relay to form topology.Moreover,we propose a greedy algorithm to allocate the limited spectrum resource for each transmitter to decrease the interference influence.