RIS-Aided Channel Construction In Random Opportunistic Networks

Random opportunistic networks is a dynamic network that relies on the movement of nodes to obtain communication opportunities with other nodes,and it is not necessary to have a complete path between the source and destination nodes of the network.Random opportunistic networks are flexible and not constrained by infrastructure,which is more suitable for communication needs in network resourceconstrained scenarios.However,there are still some problems in Random opportunistic networks.First,the constant movement of nodes in Random opportunistic networks leads to constant changes in the topology of the network at each moment,which makes many routing protocols applicable to traditional networks fail.Moreover,due to the intermittent connectivity of Random opportunistic networks,the network maintains communication for a short period of time.Finally,because the performance of each node in a random opportunistic networks varies and the probability of meeting between nodes varies,the communication delay is longer compared to that of a traditional network.Reconfigurable Intelligent Surfaces(RIS)is a communication technology with passive and low-cost characteristics,with the help of which communication channels can be constructed to complete the information transmission between nodes.By implementing RIS-assisted channel construction in Random opportunistic networks,the topology of the network can be maintained,the duration of network communication can be extended,and the communication delay can be reduced.Specifically the innovation points and work in this paper are mainly in the following parts.Firstly,the adjacency matrix of the network topology generated by the random opportunistic networks changes continuously at each moment due to its dynamic characteristics.This paper proves that the eigenvalues of the adjacency matrix are a smooth random process based on the characteristics of the eigenvalues,which provides a theoretical basis for the subsequent study.The estimated eigen-spectrum can be used to recover the network topology according to the network reconstruction algorithm,and the network reconstruction requirements are analyzed and discussed.Secondly,in the random opportunistic networks,each node can only know its own location information through the localization system,but cannot obtain the location of other nodes that are not in the communication range.Therefore,a spatio-temporal feature prediction algorithm is used to integrate the temporal features of the network node movements with the spatial features,and to estimate the current coordinates of its network nodes using the historical coordinate information of the nodes.Finally,based on the location information of the target node and the source node,we propose an algorithm for RIS channel construction,which can be reflected by RIS devices arranged in advance within the active range,through the establish a communication link and improve the inaccuracy of the target node.The simulation experiments show :In the case of inaccurate target nodes,our RISassisted channel construction algorithm can effectively find an optimal path which between each RIS device,so that achieve the communication between the target node and the source node.