Wireless power transfer (WPT) is a promising new solution to provide
convenient and perpetual energy supplies to wireless networks. In practice, WPT
is implementable by various technologies such as inductive coupling, magnetic
resonate coupling, and electromagnetic (EM) radiation, for
short-/mid-/long-range applications, respectively. In this paper, we consider
the EM or radio signal enabled WPT in particular. Since radio signals can carry
energy as well as information at the same time, a unified study on simultaneous
wireless information and power transfer (SWIPT) is pursued. Specifically, this
paper studies a multiple-input multiple-output (MIMO) wireless broadcast system
consisting of three nodes, where one receiver harvests energy and another
receiver decodes information separately from the signals sent by a common
transmitter, and all the transmitter and receivers may be equipped with
multiple antennas. Two scenarios are examined, in which the information
receiver and energy receiver are separated and see different MIMO channels from
the transmitter, or co-located and see the identical MIMO channel from the
transmitter. For the case of separated receivers, we derive the optimal
transmission strategy to achieve different tradeoffs for maximal information
rate versus energy transfer, which are characterized by the boundary of a
so-called rate-energy (R-E) region. For the case of co-located receivers, we
show an outer bound for the achievable R-E region due to the potential
limitation that practical energy harvesting receivers are not yet able to
decode information directly. Under this constraint, we investigate two
practical designs for the co-located receiver case, namely time switching and
power splitting, and characterize their achievable R-E regions in comparison to
the outer bound.

本文研究无线电信号驱动的无线功率传输技术，特别是利用多输入多输出技术实现同时无线信息和功率传输的方案，研究了三个节点的无线广播系统中提高信息传输速率和能量传输效率的最佳传输策略，通过比较时间切换和功率分配两种实用设计的实现，构建了一个速率 - 能耗区间的界限模型。