A resource allocation method for a unmanned aerial vehicle (UAV)-assisted symbiotic radio system, comprising a base station (BS) and a plurality of backscatter devices (BDs) distributed within a coverage area of the BS and a cellular user;
- wherein when the BS sends a signal to the cellular user, the BDs within the coverage area of the BS collect energy of a radio frequency signal sent from the BS and perform backscatter with a time division multiple access method, and the UAV receives backscattered signals from the BDs and collects data from all the BDs on a ground;
- wherein the resource allocation method for the symbiotic radio system comprises:
- step S1, constructing an optimization problem for the UAV-assisted symbiotic radio system by taking that maximizing a sum rate of all the BDs, and guaranteeing a minimum rate of each BD and QoS requirements of the cellular user as an objective function and constraints;
- step S2, solving the optimization problem to obtain time allocations of the BDs, reflection coefficients of the BDs and a position of the UAV of joint optimization for each time period in a preset period;
- and
- step S3, based on obtained the time allocations of the BDs, the reflection coefficients of the BDs and the position of the UAV of the joint optimization for each time period, collecting the data by the UAV-assisted symbiotic radio system in a preset cycle;
- wherein the step S3 comprises:
- dividing a total communication time T of the preset cycle into N time periods on average, wherein δ is a time length of one time period;
- step S301, the UAV flying to hover at a position qn of the UAV in a first time period obtained by the joint optimization over a range where the BDs on the ground are located, n=1;
- step S302, in response to the BS sending the signal, all BDs within the coverage area of the BS collecting energy of the signal according to a time length τk,nb allocated to the BDs and the reflection coefficients βk,n of the BDs obtained by the joint optimization;
- step S303, the BDs located within a communication range of the UAV performing backscatter with the time division multiple access (TDMA) method according to the time length τk,nb allocated to the BDs obtained by the joint optimization, and transmitting reflected information of the BDs to the UAV by using the signal sent from the BS;
- step S304, after the time length δ of one time period, the UAV collecting completely data at a current position, n=n+1, and the UAV flying to hover at the position qn of the UAV in a next time period obtained by the joint optimization;
- and
- step S305, repeating steps S302 and S304 according to the obtained time allocations of the BDs, the reflection coefficients of the BDs and the position of the UAV in the next time period of the joint optimization for each time period until the UAV returns to an initial position and collects completely the data.