Joint information and energy transfer in the spatial domain with channel estimation error

In this paper, we investigate a new technique for simultaneous information and energy transfer in multiple-input multiple-output (MIMO) networks with radio frequency (RF) energy harvesting (EH) capabilities. The proposed technique exploits the spatial decomposition of the MIMO channel and uses the eigenchannels either to convey information or to transfer energy. In order to generalize our study, we consider channel estimation error in the decomposition process and we model the interference between the eigenchannels. An optimization problem that minimizes the total transmitted power subject to information and energy constraints is formulated as a mixed-integer nonlinear program and solved to optimality by a polynomial complexity algorithm developed by exploiting the special characteristics of the problem. Numerical results show that the imperfect channel estimation is beneficial from RF - EH standpoint and is characterized by an optimal (non-zero) value.