Research On Routing Protocols For Wireless Nanosensor Networks Based On Cooperative Communication

Wireless nanosensor network(WNSN)is a new type of network.Nanosensors can be used to detect new events on the nano-scale,which traditional wireless sensor networks cannot be applied.They will be widely used in biomedical,industrial,environmental and military fields.The emergence of graphene antennas enables electromagnetic wave communication in the terahertz(THz)band(0.1–10.0 THz),and enables nano-sensors to achieve high-speed communication over a short distance.Therefore,electromagnetic communication in the THz band becomes the best way of communication in nanonetworks.However,because of the nano-size,the computing resources and energy storage of nanosensors are limited,complex calculations cannot be performed.Therefore,special protocols for nanonetworks need to be designed.At present,the research on nanonetworks is still in its infancy,and all aspects of research have not been perfected.We have studied the routing protocols of nanonetworks.The main research work is as follows:1.We have conducted full research on nanonetworks and routing protocols for nanonetworks,and made a prospect of the development of nano-network routing protocol.First,we investigate the nanonetwork routing protocols that have been proposed,and classify them based on three principles: network structure,node mobility and routing paths.Then we introduce each routing protocol and its advantages and disadvantages in detail,and compares each routing protocol.Finally,we analyzed the important factors affecting the choice of routing protocols for different applications of nanonetworks,summarized the design goals and main points of nanonetwork routing protocols,and put forward our views on future research directions.2.In order to reduce the energy consumption of the nanonetwork,we introduced cooperative transmission to the nanonetwork and proposed a sub-optimal energyefficient cooperative routing protocol(EECR).The EECR protocol aims at the transmission between two nanonodes and calculates the cooperative transmission with the lowest energy consumption.Under the two-stage cooperation model,the broadcast power of the sending node is determined according to the number of cooperative nodes,and then we calculate the transmission power required by the cooperative nodes.The nano-controller sequentially calculates the power allocation under different numbers of cooperative nodes,and selects the power allocation with the lowest energy consumption.Due to the limited computing power of the nano-controller,we adjusted the transmission power of the cooperating nodes to be the same,so the calculated lowest energy consumption power allocation was a suboptimal result.The nano-controller then returns the sub-optimal energy consumption power allocation to the sending node and the cooperative node.If the cooperative transmission energy consumption is less than the direct transmission energy consumption,the sending node and the cooperative node will perform cooperative transmission according to the allocated power.We combine EECR with two routing protocols ECR and EEMR to form the C-ECR and C-EEMR protocols.Finally,we used the NS-3 network simulator to perform simulation experiments.The simulation results show that the average energy consumption and packet loss rate of C-ECR and C-EEMR are lower than those of ECR and EEMR,indicating that the EECR protocol can effectively reduce energy consumption and packet loss rate.However,EECR will increase transmission delay,which is inevitable for two-stage cooperative transmission.3.The goal of the EECR protocol is to minimize energy consumption,but it does not consider the problem of excessive energy consumption of some nanonodes.When the energy of some nanonode is lower than the minimum transmission energy,the nanonodes will suspend participation in data transmission,causing a certain degree of packet loss.To solve this problem,we propose an Energy-Balanced Cooperative Routing(EBCR)based on cooperative transmission.This routing protocol balances the remaining energy of the nanonodes by using the nanonodes with more residual energy as cooperative nodes and allocating transmission power according to their available energy.First,we sort the candidate nodes in descending order of residual energy,and the nanonodes with more residual energy are added to the cooperative set in sequence.When there are n cooperative nodes,the part whose remaining energy is more than the remaining energy of the n +1th nanonode is its available energy.When the available energy of the cooperative nodes is sufficient to complete the cooperative transmission,the equal balance remaining energy of each cooperative node after completing the cooperative transmission is calculated,and the respective transmission power is calculated according to the remaining energy of each cooperative node.Finally,we combined EBCR with ECR and EEMR to form EB-ECR and EB-EEMR protocols,which were compared with EECR.The experimental results show that although the average energy consumption of EBCR is slightly higher than that of EECR,it can lower the packet loss rate and the network performance is better.