Scheduling in Instantaneous-Interference-Limited CR Networks with Delay Guarantees

TL;DR

This paper introduces a dynamic scheduling and power control algorithm for cognitive radio networks that guarantees average delay constraints for secondary users while respecting instantaneous interference limits to primary users, demonstrating asymptotic delay optimality and robustness.

Contribution

The paper proposes a novel Lyapunov-based scheduling and power control algorithm that ensures delay guarantees and interference protection in heterogeneous fading environments.

Findings

Algorithm achieves asymptotically delay optimal performance.

Provides delay guarantees for all secondary users.

Robust against channel estimation errors.

Abstract

We study an uplink multi secondary user (SU) cognitive radio system having average delay constraints as well as an instantaneous interference constraint to the primary user (PU). If the interference channels from the SUs to the PU have independent but not identically distributed fading coefficients, then the SUs will experience heterogeneous delay performances. This is because SUs causing low interference to the PU will be scheduled more frequently, and/or allocated more transmission power than those causing high interference. We propose a dynamic scheduling-and-power-control algorithm that can provide the required average delay guarantees to all SUs as well as protecting the PU from interference. Using the Lyapunov technique, we show that our algorithm is asymptotically delay optimal while satisfying the delay and interference constraints. We support our findings by extensive system simulations and show the robustness of the proposed algorithm against channel estimation errors.