  In this paper, the application of wireless information and power transfer to
cooperative networks is investigated, where the relays in the network are
randomly located and based on the decode-forward strategy. For the scenario
with one source-destination pair, three different strategies for using the
available relays are studied, and their impact on the outage probability and
diversity gain is characterized by applying stochastic geometry. By using the
assumptions that the path loss exponent is two and that the relay-destination
distances are much larger than the source-relay distances, closed form
analytical results can be developed to demonstrate that the use of energy
harvesting relays can achieve the same diversity gain as the case with
conventional self-powered relays. For the scenario with multiple sources, the
relays can be viewed as a type of scarce resource, where the sources compete
with each other to get help from the relays. Such a competition is modeled as a
coalition formation game, and two distributed game theoretic algorithms are
developed based on different payoff functions. Simulation results are provided
to confirm the accuracy of the developed analytical results and facilitate a
better performance comparison.
