Resource Allocation In SWIPT Aided Cooperative Relay

In the era of beyond 5G(B5G),plenty of devices are swarming into the wireless networks,which results in the more frequent communications between network nodes.Due to the terrible wireless channel,the performance of data transmission between nodes are seriously degraded.Therefore,relay is becoming a promising technology to enable relay nodes to forward data information from a source node to a destination node.However,additional data forwarding consumes much energy,which constrains the selfwork of all the relay nodes.Considering the fairness,it's becoming a challenge to enable the relay nodes to forwarde data information without consuming their own energy.Thanks to the advantage that wireless information and wireless energy could be transferred simultaneously to the uder devices,simultaneous wireless information and power transfer(SWIPT)has been researched for years,which is considered as a promising technology in the future networks.By merging SWIPT and relay together,relay nodes are able to harvest additional energy at the same time receiving data information,which could meet both the data and energy requirements.The efficiency of data forwarding could be further improved.In this paper,resource allocation in the relay scenarios with SWIPT is studied,where all the relay nodes could receive data information as well as harvest energy from the source node,and then use the harvested energy to forward data information to the destination node.In order to guarantee the forwarding efficiency as well as save energy,selective decoding and forwarding(S-DF)relay technology is conceived in the network,where the relay node should firstly decode the received information and then forward to the destination node if no mistake occurs.Compared with traditional decoding and forwarding(DF)relay technology,S-DF prevents the additional energy waste due to the transmission of the incorrect data information,whichi could further improve the throughput performance.Meanwhile,to be more practical,the decoding energy consumption at the relay node is also considered in the system.In this paper,the two-way relay scenario as well as the cooperative relay scenario are both studied,considering the difference that whether the direct communication link exists between the source node and the destination node.Then,based on the modelling and analysis of time correlated wireless channel,the optimal relay selection,beamforming at the source node as well as the power splitting ratio and forwarding power at the relay node are jointly obtained in both the two-way relay scenario as well as the cooperative relay scenario,in order to maximize the throughput between the source node and the destination node.Simulation results shows that compared with traditional decoding and forwarding(DF)relay technology,S-DF achieves a higher end-to-end throughput performance.