Title :
Optimal Subcarrier and Power Allocation under Interference Temperature Constraints
Author :
Lu, Qianxi ; Peng, Tao ; Wang, Wei ; Wang, Wenbo
Author_Institution :
Wireless Signal Process. & Network Lab., Beijing Univ. of Posts & Telecommun., Beijing
Abstract :
Cognitive radio makes it possible for an unlicensed user to access a licensed spectrum opportunistically on the basis of non-interfering. This paper addresses the problem of resource allocation for multiaccess channel (MAC) of OFDMA-based cognitive radio networks, taking into account of the interference temperature constraints. The objective is to maximize the system utility, which is used to quantify different quality-of-service (QoS) requirements of different users. Firstly, a theoretical framework is provided, where necessary and sufficient conditions for optimal subcarrier assignment and power allocation are presented under certain constraints. Then, an effective algorithm is devised for more practical conditions based on Lagrangian duality theory, where subgradient/ellipsoid method is applied for Lagrangian multipliers iteration. With polynomial time complexities, the proposed resource allocation algorithm is proved to achieve optimal system performance by numerical results.
Keywords :
OFDM modulation; cognitive radio; frequency division multiple access; gradient methods; radiofrequency interference; resource allocation; Lagrangian duality theory; Lagrangian multiplier; OFDMA-based cognitive radio network; ellipsoid method; interference temperature constraint; multiaccess channel; optimal subcarrier; polynomial time complexity; power allocation; quality-of-service; resource allocation; subgradient method; Cognitive radio; Constraint theory; Ellipsoids; Interference constraints; Lagrangian functions; Polynomials; Quality of service; Resource management; Sufficient conditions; Temperature;
Conference_Titel :
Wireless Communications and Networking Conference, 2009. WCNC 2009. IEEE
Conference_Location :
Budapest
Print_ISBN :
978-1-4244-2947-9
Electronic_ISBN :
1525-3511
DOI :
10.1109/WCNC.2009.4917870