Precoding Design and Power Allocation in Two-User MU-MIMO Wireless Ad Hoc Networks

Abstract

Abstract:In this paper, we consider the precoding design and power allocation problem for multi-user multiple-input multiple-output (MU-MIMO) wireless ad hoc networks. In the first timeslot, the source node (SN) transmits energy and information to a relay node (RN) simultaneously within the simultaneous wireless information and power transfer (SWIPT) framework. Then, in the second timeslot, based on the decoder and the forwarding (DF) protocol, after reassembling the received signal and its own signal, the RN forwards the information to the main user (U1) and simultaneously sends its own information to the secondary user (U2). In this paper, when the transmission rate of the U1 is restricted, the precoding, beamforming, and power splitting (PS) transmission ratio are jointly considered to maximize the transmission rate of U2. To maximize the system rate, we design an optimal beamforming matrix and solve the optimization problem by semi-definite relaxation (SDR), considering the high complexity of implementing the optimal solution. Two sub-optimal precoding programs are also discussed: singular value decomposition and block diagonalization. Finally, the performance of the optimization and sub-optimization schemes are compared using a simulation.

Ocean Surface Drifting Buoy System Based on UAV-Enabled Wireless Powered Relay Network

“…where V max denotes the maximum achievable speed of the UAV. For problem P1, the objective function is nonconcave and constraints (15), (19), and (21) are nonconvex due to the complicated throughput and energy functions with respect to coupled variables such as the UAV trajectory and subslot allocation scheme. According to the definition of convex optimization [37], P1 is a nonconvex optimization problem that is difficult to be optimally solved in general.…”

“…For any given UAV trajectory U [n] and resource allocation P I [n], P E [n], and P k [n], the optimal allocation problem of subslot δ 0 [n], δ k [n] and δ K+1 [n] in the r-th iteration can be given as (19), (21), (22).…”

“…Wireless communication networks based on WET technology have been widely considered in terrestrial scenarios [18][19][20], and the wireless powered communication network (WPCN) is one of the representative technologies [21]. A typical WPCN employs a hybrid access point (H-AP) that acts as a power station to broadcast RF energy signals to the ground terminals during the downlink and as an information receiver station in the uplink.…”

Theoretical Derivation and Optimization Verification of BER for Indoor SWIPT Environments

“…Simultaneous wireless information and power transfer (SWIPT) has been widely investigated recently [1][2][3][4][5][6][7][8][9][10][11][12]. SWIPT does not only provide a high spectral efficiency of wireless systems, but it also provides energy via ambient radio frequency electromagnetic waves.…”

“…Robust beamforming was studied on the assumption of imperfect channel state information at the transmitter in the literature [6]. In the work of [7], the analytic solution was used to optimize the beamforming technology of the SWIPT system. In the literature [10], the allocation of a multi-object resource for secured communication in recognizable radio networks was studied.…”