Power Allocation in OFDM Based Cognitive Radio System

  • Ishrat Maherin
  • Qilian Liang
Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 202)


In this chapter, we investigate one suboptimal power allocation scheme for an OFDM based cognitive radio system. Optical power allocation for secondary user in OFDM subcarrier is complex since it has a power as well as an interference constraint. Mathematical analysis shows that interference between primary and secondary in OFDM based system depends on theirs spectral distance. In our suboptimal method we consider the spectral distance between the secondary and primary user and modify the traditional water-filling algorithm. By applying our suboptimal power allocation method, it is possible that we can get good performance comparable to the optimal scheme. We compare our method with traditional power allocations schemes like equal power allocation and water filling power allocation. Result shows that distance dependent modified water filling (DDMWF) scheme can achieve the highest data rate for the cognitive radio based Secondary user.


Cognitive radio Water filling OFDM Power allocation 



This work was supported in part by National Science Foundation (NSF) under grant CNS-0964713, CNS-1050618 and office of Naval research (ONR) under grant N00014-11-1-0071 and N00014-11-1-0865.


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Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  1. 1.Department of Electrical EngineeringUniversity of Texas at ArlingtonArlingtonUSA

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