Decentralized Simultaneous Information and Energy Transmission in K-User Multiple Access Channels
Abstract
In this paper, the fundamental limits of decentralized simultaneous information and energy transmission in the K-user Gaussian multiple access channel (G-MAC), with an arbitrary K ≥slant 2 and one non-colocated energy harvester (EH), are fully characterized. The objective of the transmitters is twofold. First, they aim to reliably communicate their message indices to the receiver; and second, to harvest energy at the EH at a rate not less than a minimum rate requirement b. The information rates R1,…,RK, in bits per channel use, are measured at the receiver and the energy rate B is measured at an EH. Stability is considered in the sense of an η-Nash equilibrium (η-NE), with η > 0. The main result is a full characterization of the η-NE information-energy region, i.e., the set of information-energy rate tuples (R1,…,RK,B) that are achievable and stable in the G-MAC when: (a) all the transmitters autonomously and independently tune their own transmit configurations seeking to maximize their own information transmission rates R1,…, RK; and (b) all the transmitters jointly guarantee an energy transmission rate B at the EH, such that B ≥slant b. Therefore, any rate tuple outside the η-NE region is not stable as there always exists at least one transmitter able to increase by at least η bits per channel use its own information transmission rate by updating its own transmit configuration.