On the Effect of Blockage Objects in Dense MIMO SWIPT Networks

Abstract

Simultaneous wireless information and power transfer (SWIPT) is characterized by the ambiguous role of multi-user interference. In short, the beneficial effect of multi-user interference on RF energy harvesting is obtained at the price of a reduced link capacity, thus originating nontrivial tradeoffs between the achievable information rate and the harvestable energy. Arguably, in indoor environments, this tradeoff might be affected by the propagation loss due to blockage objects like walls. Hence, a couple of fundamental questions arise. How much must the network elements be densified to counteract the blockage attenuation? Is blockage always detrimental on the achievable rate-energy tradeoff? In this paper, we analyze the performance of an indoor multiple-input multiple-output SWIPT-enabled network in the attempt to shed a light of those questions. The effects of the obstacles are examined with the help of a stochastic geometry approach in which the locations of energy sources (also referred to as power heads) are distributed by using a Poisson point process and walls are generated through a Manhattan Poisson line process. The stochastic behavior of the signal attenuation and the multi-user interference is studied to obtain the joint complementary cumulative distribution function of information rate and harvested power. Theoretical results are validated through Monte Carlo simulations. Eventually, the rate-energy tradeoff is presented as a function of the density of walls to emphasize the cross-dependences between the deployment of the network elements and the macro parameters characterizing the topology of the venue.