Backscatter-Assisted Cooperative Communication Method In Wireless Powered Communication Network

The emerging wireless power communication system utilizes the transmission characteristics of radio frequency signals to provide energy for wireless devices from a long distance.Compared with the traditional battery-based system,the communication interruption probability is greatly reduced,and the operate time of the device is prolonged.Due to the path loss of electromagnetic waves,many users at the edge of the network will face the problem of unbalanced communication quality.The emergence of cooperative communication has alleviated the above problems.The multi-user assistance in transmitting each other's information can effectively obtain the diversity gain,which significantly improves the effective communication distance and quality.However,the mutual transfer of cooperative information between users in the process of cooperative communication will inevitably lead to energy loss and time loss,which has a great influence on the overall communication performance of the system.Therefore,how to design an effective user cooperation method in a wireless powered communication network and reduce the overhead generated by cooperation is of great significance for improving communication efficiency.The main work of this paper is to study a new user cooperative communication method applied in the wireless power communication network.Based on the application of the emerging backscatter communication technology,the method reuses the time for energy transmission in the system,and transmits its own information to other users through the reflected energy signal,thereby saving the link for exchanging information and reducing the energy consumption and time consumption of cooperative communication.At this stage,we propose a device that uses an energy splitting circuit at the information receiver for simultaneous energy harvesting and information decoding.And in the subsequent information transmission phase,the multi-user completes the cooperative communication through the space-time coding technology,and uses the collected energy to jointly transmit the information to the receiving station.By virtue of the diversity gain brought by the virtual antenna array formed by the users and the energy-saving backscatter communication technology,this cooperative communication method can efficiently reuse the transmission time of the wireless energy and is effective in alleviate the overhead of traditional cooperative communication.In this paper,we will analyze and discuss the dual-user model and multi-user model separately,and use the optimization algorithm to optimize the time allocated to the energy and information transmission phase to maximize the common throughput of users.Finally,through numerical simulation analysis,the advantages of the proposed method compared with the previous schemes are studied,and the effectiveness and reliability of the scheme in different application scenarios are demonstrated.