Open AccessEnergy‐Efficient Power Allocation for Cognitive Radio Networks with Joint Overlay and Underlay Spectrum Access Mechanism
Author(s) -
Zuo Jiakuo,
Zhao Li,
Bao Yongqiang,
Zou Cairong
Publication year - 2015
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.15.0114.0739
Subject(s) - cognitive radio , mathematical optimization , underlay , computer science , throughput , fractional programming , optimization problem , overlay , interference (communication) , convex optimization , orthogonal frequency division multiplexing , mathematics , wireless , computer network , nonlinear programming , signal to noise ratio (imaging) , regular polygon , telecommunications , channel (broadcasting) , physics , geometry , nonlinear system , quantum mechanics , programming language
Traditional designs of cognitive radio (CR) focus on maximizing system throughput. In this paper, we study the joint overlay and underlay power allocation problem for orthogonal frequency‐division multiple access–based CR. Instead of maximizing system throughput, we aim to maximize system energy efficiency (EE), measured by a “bit per Joule” metric, while maintaining the minimal rate requirement of a given CR system, under the total power constraint of a secondary user and interference constraints of primary users. The formulated energy‐efficient power allocation (EEPA) problem is nonconvex; to make it solvable, we first transform the original problem into a convex optimization problem via fractional programming, and then the Lagrange dual decomposition method is used to solve the equivalent convex optimization problem. Finally, an optimal EEPA allocation scheme is proposed. Numerical results show that the proposed method can achieve better EE performance.