Research On Relay Selection Algorithms In Wireless Sensor Netwoks

In Cooperative Relaying-WSNs(CR-WSNs),source node and destination node can transmit data with the assistance of relay nodes.In order to further improve system performance,Simultaneous Wireless Information and Power Transfer(SWIPT)technol-ogy and Rateless Codes(RCs)technology are adopted in CR-WSNs.SWIPT transforms the wireless signal into energy and information and thus the information and energy can be optimized.It also changes the energy transfer mode and solves the energy limitation problem of CR-WSNs.RCs changes information receiving mode,so that information can be partially accumulated on the receivers.Also,it improves data transmission effi-ciency.However,the change of the energy transfer mode and the information receiving mode bring some challenges in the design of relay selection algorithms.How to deal with these challenges and choose the best relay to maximize CR-WSNs system through-put is still an urgent problem to be solved.In the two-hop CR-WSNs and the multi-hop CR-WSNs based on SWIPT and RCs,this dissertation proposes the relay selection al-gorithm with the system resources allocation to maximize the throughput of the system.The main works are as follows:In the two-hop CR-WSNs based on SWIPT and RCs,since transmission power allocation and transmission time of the relay is restricted for energy allocation and in-formation allocation,which affects the relay selection strategy and the throughput of the system,a novel relay selection algorithm is proposed.The relay selection algorithm considers the ratio of energy and information allocation,the transmission power allo-cation and the transmission time allocation to maximize the throughput of the system.In order to solve the algorithm,a relay selection problem is modeled as a non-convex optimization problem.And we use a Lagrange dual method to decouple the problem,then the optimal relay selection strategy and system maximum throughput are obtained.In the multi-hop CR-WSNs based on SWIPT and RCs,Since the transmission power of the relay is constrained by energy allocation,and since the information ac-cumulation of the next-hop relay is restricted on information allocation,both of which influence the system throughput.we devise a new SWIPT-Rateless Codes Routing al-gorithm(S-RCR)to maximize the throughput of the system.The algorithm combines the routing metrics of resources allocation,such as the allocation of the energy,the information,the transmission power and the transmission time.Based on the routing metrics,routing paths are selected,making the system of the the throughput maximized.