Distributed algorithm under cooperative or competitive priority users in cognitive networks

Mahmoud Almasri,Ali Mansour,Christophe Osswald,Denis Lejeune,Ammar Assoum,Christophe Moy

doi:10.1186/s13638-020-01738-w

Abstract

Opportunistic spectrum access (OSA) problem in cognitive radio (CR) networks allows a secondary (unlicensed) user (SU) to access a vacant channel allocated to a primary (licensed) user (PU). By finding the availability of the best channel, i.e., the channel that has the highest availability probability, a SU can increase its transmission time and rate. To maximize the transmission opportunities of a SU, various learning algorithms are suggested: Thompson sampling (TS), upper confidence bound (UCB), ε-greedy, etc. In our study, we propose a modified UCB version called AUCB (Arctan-UCB) that can achieve a logarithmic regret similar to TS or UCB while further reducing the total regret, defined as the reward loss resulting from the selection of non-optimal channels. To evaluate AUCB’s performance for the multi-user case, we propose a novel uncooperative policy for a priority access where the kth user should access the kth best channel. This manuscript theoretically establishes the upper bound on the sum regret of AUCB under the single or multi-user cases. The users thus may, after finite time slots, converge to their dedicated channels. It also focuses on the Quality of Service AUCB (QoS-AUCB) using the proposed policy for the priority access. Our simulations corroborate AUCB’s performance compared to TS or UCB.

Highlights

1.1 Cognitive radioThe static spectrum allocation has nowadays become a major problem in wireless networks as it results in an inefficient use of the spectrum and can generate holes or white spaces therein
We notice that our algorithm presents the smaller regret. 4.2 The performance of the priority learning access (PLA) policy This section investigates the performance of the PLA policy under AUCB and upper confidence bound (UCB) compared to the musical chair [31] and SLK [33], and 4 priority users are considered to access the channels based on their prior rank
5 Conclusion In this paper, we investigated the problem of opportunistic spectrum access (OSA) in cognitive radio networks, where a secondary (unlicensed) user (SU) tries to access primary (licensed) user (PU)’ channels and find the best available channel as fast as possible

Summary

Introduction

1.1 Cognitive radioThe static spectrum allocation has nowadays become a major problem in wireless networks as it results in an inefficient use of the spectrum and can generate holes or white spaces therein. The opportunistic spectrum access (OSA) concept aims at reducing the inefficient use of the spectrum by sharing available spectrum of primary users (PUs), i.e., licensed users who have full access to a frequency band, with opportunistic users called secondary users (SUs). According to OSA, a SU may at any time access an unoccupied frequency band, but it must abandon the targeted channel whenever a PU restarts its Almasri et al EURASIP Journal on Wireless Communications and Networking (2020) 2020:145 transmission in its channel. OSA optimizes the use of the spectrum with minimum impacts on PUs and minimizing interference among SUs. OSA is an important strategy for the cognitive radio (CR) [1]; a CR unit must execute a cognitive cycle in order to implement an OSA strategy. The main three steps of the cognitive cycle are as follows:

Objectives

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Conclusion