TITLE:
User-Based Discrete-Time Queuing Analysis for Opportunistic Spectrum Access in Cognitive Radio Networks
AUTHORS:
Lei Zhang, Shanzhi Mou, Yu Wang
KEYWORDS:
Cognitive Radio Networks, Macro-Level Spectrum Access, Discrete-Time Queuing Theory, Matrix-Geometric Solution, Access Control
JOURNAL NAME:
Advances in Pure Mathematics,
Vol.9 No.1,
January
10,
2019
ABSTRACT: In cognitive radio networks, the
spectrum utilization can be improved by cognitive users opportunistically using
the idle channels licensed to the primary users. However, the new arrived
cognitive users may not be able to use the channel immediately since the
channel usage state is random. This will impose additional time delay for the
cognitive users. Excessive waiting delay can make cognitive users miss the
spectrum access chances. In this paper, a discrete-time Markov queuing model
from a macro point of view is provided. Through the matrix-geometric solution
theory, the average sojourn time for cognitive users in the steady state before
accessing the spectrum is obtained. Given the tolerant delay of cognitive
users, the macro-based throughput is derived and an access control mechanism is
proposed. The numerical results show the effects of service completion
probability on average sojourn time and throughput. It is confirmed that the
throughput can be obviously improved by using the proposed access control
mechanism. Finally, the performance evaluations based on users are compared to
that based on data packets.