On Orthogonal Band Allocation for Multi-User Multi-Band Cognitive Radio Networks: Stability Analysis

TL;DR

This paper analyzes the stability of orthogonal band allocation in multi-user cognitive radio networks, demonstrating its advantages over random and fixed assignment methods through theoretical and numerical results.

Contribution

It introduces a linear programming framework for stability analysis of orthogonal band allocation, showing its superiority over other low-complexity schemes.

Findings

Orthogonal allocation has a larger stability region.

The linear program efficiently characterizes stability boundaries.

Numerical results confirm the advantages of orthogonal allocation.

Abstract

In this work, we study the problem of band allocation of $M_s$ buffered secondary users (SUs) to $M_p$ primary bands licensed to (owned by) $M_p$ buffered primary users (PUs). The bands are assigned to SUs in an orthogonal (one-to-one) fashion such that neither band sharing nor multi-band allocations are permitted. In order to study the stability region of the secondary network, the optimization problem used to obtain the stability region's envelope (closure) is established and is shown to be a linear program which can be solved efficiently and reliably. We compare our orthogonal allocation system with two typical low-complexity and intuitive band allocation systems. In one system, each cognitive user chooses a band randomly in each time slot with some assignment probability designed such that the system maintained stable, while in the other system fixed (deterministic) band assignment is adopted throughout the lifetime of the network. We derive the stability regions of these two systems. We prove mathematically, as well as through numerical results, the advantages of our proposed orthogonal system over the other two systems.