Joint Resource Allocation And Cooperative Transmission In Distributed Wireless Powered Communication Networks

In traditional battery powered wireless sensor networks,wireless devices require frequent recharging or replacement of the depleted batteries manually.Traditional renewable energy sources such as solar and wind cannot provide a stable energy supply to sensors.Given the costly and inconvenient way to recharge,wireless powered communication network(WPCN)becomes a promising solution to achieve a sustainable energy supply for information transmission in which the low-power sensor nodes or terminals harvest energy from received radio frequency signals broadcast by the communication devices.It is of great significance of research on resource allocation algorithm since the transmission performance optimization closely related to the resource allocation.We consider a distributed WPCN with one center processor(CP),multiple remote radio heads(RRHs)and multiple terminal nodes.RRHs have dual functions:transferring wireless energy and forwarding information from terminals to CP.We focus on the joint resource allocation in the distributed WPCN.Therefore,the main works of this paper are as follows:1)When the number of transmitted bits from terminal to RRH is given,the Generalized Benders Decomposition(GBD)is used to jointly optimize the association factors,the RRHs'downlink charge time and charge power,the RRHs'uplink transmission time and transmit power,terminals'the uplink transmission time and transmit power.By GBD,the original problem decomposed into the relaxed master problem and time and power allocation problem and then we solve the two problems alternately.We can get the optimal solution by generating a series upper bounds and lower bounds.2)When the association factor of terminals and RRHs is given,we jointly optimize the number of transmit bits from terminals to RRHs,RRHs' downlink charge time and charge power,RRHs' uplink transmission time and transmit power,terminals'uplink transmission time and transmit power utilizing Alternating Direction Multiplier Method(ADMM).We take the form of a decomposition-coordination procedure,in which the solutions to four local subproblems are coordinated to find a solution of the global problem.The ADMM algorithm takes advantage of this divide-and-conquer idea,which not only reduces the dimension of the problem,but also speeds up the resource allocation problem.