CFO compensation for uplink OFDMA systems with conjugated gradient

Kilbom Lee, Inkyu Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

12 Citations (Scopus)

Abstract

In this paper, we propose an iterative lowcomplexity carrier frequency offset (CFO) compensation algorithm based on the conjugate gradient (CG) method for uplink orthogonal frequency division multiple access systems. In general, a linear minimum mean square error (MMSE) CFO compensation algorithm is simple and efficient, but it requires an inverse operation to compute the MMSE solution of the CFOinduced inter-carrier interference (ICI) matrix whose size equals the number of subcarriers. Thus, the computational complexity becomes prohibitively high when the number of subcarriers is large. To address this issue, we employ the iterative CG method to solve linear equations whose matrix is Hermitian positivedefinite. First, we derive the eigenvalue distribution of the CFOinduced ICI matrix. Based on the distribution, we present several observations which lead to the iteration number required for the convergence. Especially, the analysis shows that for an interleaved carrier assignment scheme, the maximum iteration number to compute an exact solution is at most the same as the number of mobile units. Simulation results exhibit that the proposed scheme can yield almost the same bit error rate performance of the MMSE compensation algorithm with substantially reduced computational complexity and memory requirements.

Original languageEnglish
Title of host publicationIEEE International Conference on Communications
DOIs
Publication statusPublished - 2011 Sep 2
Event2011 IEEE International Conference on Communications, ICC 2011 - Kyoto, Japan
Duration: 2011 Jun 52011 Jun 9

Other

Other2011 IEEE International Conference on Communications, ICC 2011
CountryJapan
CityKyoto
Period11/6/511/6/9

Fingerprint

Mean square error
Conjugate gradient method
Computational complexity
Error compensation
Frequency division multiple access
Linear equations
Bit error rate
Data storage equipment
Compensation and Redress

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Computer Networks and Communications

Cite this

Lee, K., & Lee, I. (2011). CFO compensation for uplink OFDMA systems with conjugated gradient. In IEEE International Conference on Communications [5962693] https://doi.org/10.1109/icc.2011.5962693

CFO compensation for uplink OFDMA systems with conjugated gradient. / Lee, Kilbom; Lee, Inkyu.

IEEE International Conference on Communications. 2011. 5962693.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Lee, K & Lee, I 2011, CFO compensation for uplink OFDMA systems with conjugated gradient. in IEEE International Conference on Communications., 5962693, 2011 IEEE International Conference on Communications, ICC 2011, Kyoto, Japan, 11/6/5. https://doi.org/10.1109/icc.2011.5962693
Lee, Kilbom ; Lee, Inkyu. / CFO compensation for uplink OFDMA systems with conjugated gradient. IEEE International Conference on Communications. 2011.
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