Long-Term Energy Constraints and Power Control in Cognitive Radio Networks

TL;DR

This paper investigates how long-term energy constraints influence power control strategies in cognitive radio networks, focusing on secondary users' access opportunities and game-theoretic interactions with primary users.

Contribution

It introduces a framework analyzing the impact of energy constraints on secondary user access and models the interaction as a Stackelberg game for power control.

Findings

Secondary users can exploit unused time-slots without interfering with primary users.

The fraction of available time-slots depends on system parameters and energy constraints.

Stackelberg game analysis reveals equilibrium power control policies for primary and secondary users.

Abstract

When a long-term energy constraint is imposed to a transmitter, the average energy-efficiency of a transmitter is, in general, not maximized by always transmitting. In a cognitive radio context, this means that a secondary link can re-exploit the non-used time-slots. In the case where the secondary link is imposed to generate no interference on the primary link, a relevant issue is therefore to know the fraction of time-slots available to the secondary transmitter, depending on the system parameters. On the other hand, if the secondary transmitter is modeled as a selfish and free player choosing its power control policy to maximize its average energy-efficiency, resulting primary and secondary signals are not necessarily orthogonal and studying the corresponding Stackelberg game is relevant to know the outcome of this interactive situation in terms of power control policies.