QoS Analysis of Cognitive Radio Channels with Perfect CSI at both Receiver and Transmitter

TL;DR

This paper analyzes the maximum throughput of cognitive radio channels with perfect channel state information at both transmitter and receiver, considering QoS constraints and optimizing power adaptation based on primary user activity.

Contribution

It introduces a state transition model for cognitive channels with QoS constraints and evaluates how system parameters affect effective capacity.

Findings

Optimal power adaptation policies improve throughput.

Channel sensing parameters significantly impact effective capacity.

QoS constraints limit maximum achievable throughput.

Abstract

In this paper, cognitive transmission under quality of service (QoS) constraints is studied. In the cognitive radio channel model, it is assumed that both the secondary receiver and the secondary transmitter know the channel fading coefficients perfectly and optimize the power adaptation policy under given constraints, depending on the channel activity of the primary users, which is determined by channel sensing performed by the secondary users. The transmission rates are equal to the instantaneous channel capacity values. A state transition model with four states is constructed to model this cognitive transmission channel. Statistical limitations on the buffer lengths are imposed to take into account the QoS constraints. The maximum throughput under these statistical QoS constraints is identified by finding the effective capacity of the cognitive radio channel. The impact upon the effective capacity of several system parameters, including the channel sensing duration, detection threshold, detection and false alarm probabilities, and QoS parameters, is investigated.