Joint Optimization of SWIPT Enabled Ambient Backscatter Communication System with Multiple Antennas

Internet of Things (IoT) is the connections of embedded technologies that can be used to communicate and interact with the surroundings. Moreover, the ambient backscatter communication system (ABCS) as one of the IoT technologies has attracted extensive attentions in both academia and industries. Then the simultaneous wireless information and power transfer (SWIPT) enabled scheme was designed and proposed based on the two-hop ABCS architecture, where the source and destination node were all equipped with multiple antennas and the maximum ratio transmission (MRT) precoding and maximum ratio combination (MRC) were adopted respectively in the proposed system. For the established massive node transmission system, the transmission power, the number of source antennas and destination antennas were optimized by the proposed joint optimization algorithm to obtain the maximum energy efficiency of the ABCS system. Since the original optimization was non-convex problem, which can be transformed to convex optimization via the large SNR approximation method and thereby the optimal solution of the optimization problem was derived through the Lagrange algorithm and the Lambert function W. The simulation results showed that the proposed scheme can achieve remarkable energy efficiency compared with other optimization schemes and verified the correctness of the theoretical analysis.