On Stable Throughput of Cognitive Radio Networks With Cooperating Secondary Users

TL;DR

This paper analyzes the stable throughput of cooperative cognitive radio networks with multiple secondary users, focusing on primary-secondary cooperation, imperfect sensing, and optimal secondary transmission strategies.

Contribution

It introduces and analyzes three variations of cooperative methods, providing closed-form throughput expressions and optimal transmission probabilities for secondary users.

Findings

Cooperative methods improve primary and secondary throughput.

Imperfect sensing impacts interference and throughput.

Optimal secondary transmission maximizes individual secondary throughput.

Abstract

In this paper, we study cooperative cognitive radio networks consisting of a primary user and multiple secondary users. Secondary users transmit only when primary user is sensed as silent and may interfere with primary transmission due to imperfect sensing. When primary activity is sensed correctly, secondary users cooperate with primary user by assisting retransmission of failed packets of primary user. We analyze packet throughput of primary and secondary users for three variations of proposed cooperation method. Signal flow graph (SFG) based approach is employed to obtain closed form expressions of packet throughput. The analysis is done for two cases; individual sensing and cooperative sensing. Further, we characterize optimal transmission probability of secondary users that maximizes individual secondary packet throughput keeping all queues in the system stable. Results present a comparison of throughput performance of proposed cooperation methods under different scenarios and show their benefits for both primary as well as secondary user throughput.