Feedback Enhances Simultaneous Wireless Information and Energy Transmission in Multiple Access Channels

Selma Belhadj Amor (1) , Samir M. Perlaza (1) , Ioannis Krikidis (2) , H. Vincent Poor (3)

1 SOCRATE - Software and Cognitive radio for telecommunications
2 UCY - University of Cyprus [Nicosia]
3 Princeton University

In this report, the fundamental limits of simultaneous information and energy transmission in the two-user Gaussian multiple access channel (G-MAC) with and without feedback are fully characterized. All the achievable information and energy transmission rates (in bits per channel use and Joules per channel use respectively) are identified. Thus, the capacity-energy region is defined in both cases. In the case without feedback, an achievability scheme based on power-splitting and successive interference cancelation is shown to be optimal. Alternatively, in the case with feedback (G-MAC-F), a simple yet optimal achievability scheme based on power-splitting and Ozarow's capacity achieving scheme is presented. Three of the most important observations in this work are: (a) The capacity-energy region of the G-MAC without feedback is a proper subset of the capacity-energy region of the G-MAC-F; (b) Feedback can at most double the energy rate for a fixed information rate; and (c) Time-sharing with power control is strictly suboptimal in terms of sum-rate in both the G-MAC with and without feedback.

Mots clés: Feedback; Gaussian multiple access channel; simultaneous information and energy transmission; RF harvesting; capacity-energy region.

Domaines: Théorie de l'information [cs.IT]; Théorie de l'information et codage [math.IT]

Selma Belhadj Amor, Samir M. Perlaza, Ioannis Krikidis, H. Vincent Poor. Feedback Enhances Simultaneous Wireless Information and Energy Transmission in Multiple Access Channels. [Research Report] 8804, INRIA Grenoble - Rhône-Alpes. 2015. ⟨hal-01223586v1⟩