Simultaneous wireless information and power transfer based on generalized triangular decomposition

In this paper, a new approach, based on the generalized triangular decomposition (GTD), is proposed for simultaneous wireless information and power transfer (SWIPT) in the spatial domain for a point-to-point multiple-input multiple-output (MIMO) system. The proposed approach takes advantage of the GTD structure to allow the transmitter to use the strongest eigenchannel jointly for energy harvesting and information exchange while these transmissions can be separated at the receiver. The optimal structure of the GTD that maximizes the total information rate constrained by a given power allocation and a required amount of energy harvesting is derived. An algorithm is developed that minimizes the total transmitted power for given information rate and energy harvesting constraints with a limited total power at the transmitter. Both theoretical and simulation results show that our proposed GTD based SWIPT outperforms singular value decomposition (SVD) based SWIPT. This is due to the flexibility introduced by the GTD to increase the energy harvested via interstream interference

Simultaneous Wireless Information and Power Transfer Based on Generalized Triangular Decomposition

The rapidly growing number of wireless devices has raised the need for designing self-sustained wireless systems. Simultaneous wireless information and power transfer (SWIPT) has been advocated as a promising solution. Various approaches have emerged to design wireless systems that enable SWIPT. In this thesis, we propose a novel approach for spatial switching (SS) based SWIPT using the generalized triangular decomposition (GTD) for point-to-point multiple-input-multiple-output (MIMO) systems. The GTD structure allows the transmitter to use the highest gain subchannels jointly for energy and information transmissions and these joint transmissions can be separated at the receiver. We first derive the optimal GTD structure to attain optimal performance in SS based SWIPT systems. This structure is then extended to design three novel transceivers where each transceiver achieves a certain objective and meets specific constraints. The first transceiver focuses on minimizing the total transmitted power while satisfying the energy harvesting and data rate constraints at the receiver. The second transceiver targets the data rate maximization while meeting a certain amount of energy at the receiver. The third transceiver considers the energy harvesting maximization and guarantees to satisfy the required data rate constraint. The proposed transceivers are designed assuming two transmitted power constraints at the transmitter; the instantaneous total transmit power and the limited transmit power per subchannel. For each designed transceiver, optimal and/or suboptimal solutions are developed to obtain joint power allocation and subchannel assignment under a linear energy harvesting model. Additionally, a novel extension to the SS based SWIPT system is proposed considering a non-linear energy harvesting model. Thereafter, the case of maximizing the energy harvesting for a given data rate and instantaneous total transmitted power constraints is studied. A solution is developed that obtains jointly the optimal power allocation and the subchannel assignment alongside the optimal and/or suboptimal split ratios at the energy harvesters. The theoretical and simulation results show that our novel proposed GTD designs for both linear and non-linear energy harvesting models outperform the state-of-the-art singular value decomposition (SVD) based SWIPT designs