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Resource allocation for SC‐FDMA based cognitive radio systems
Author(s) -
Ahmad Ayaz,
Raza Khan Mohammad Toaha
Publication year - 2015
Publication title -
international journal of communication systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.344
H-Index - 49
eISSN - 1099-1131
pISSN - 1074-5351
DOI - 10.1002/dac.3046
Subject(s) - subcarrier , computer science , resource allocation , constraint (computer aided design) , cognitive radio , interference (communication) , transmitter power output , mathematical optimization , orthogonal frequency division multiple access , adjacency list , optimization problem , frequency division multiple access , power (physics) , algorithm , orthogonal frequency division multiplexing , computer network , transmitter , telecommunications , mathematics , wireless , channel (broadcasting) , geometry , physics , quantum mechanics
Summary This paper presents resource allocation algorithms for secondary user (SU) transmitters of single‐carrier frequency division multiple access (SC‐FDMA)‐based cognitive radio systems. In addition to the conventional per‐SU transmit power constraints, we also consider two types of interference constraints on SUs to protect the primary users links and thereby formulate two resource allocation problems. The first constraint relates to individual per‐subcarrier interference power, whereas the second constraint corresponds to joint sum of interference power across all the subcarriers and SUs. In SC‐FDMA system, a subcarrier can be allocated to one SU at a time (exclusivity constraint), and the multiple subcarriers allocated to an SU must be adjacent to each other (adjacency constraint). These constraints make the resource allocation problem prohibitively difficult to solve. We derive efficient power and subcarrier allocation algorithms via convex optimization techniques for both problems. We compare the results of our proposed algorithm with the existing schemes. Numerical results show that our algorithms can improve the system performance significantly. Copyright © 2015 John Wiley & Sons, Ltd.