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Using Unclaimed Sub-carriers in Opportunistic OFDMA Systems
KTH, School of Electrical Engineering (EES), Signal Processing.
Electrical and Computer Engineering Dept., University of Delaware, Newark, DE 19716, USA..
KTH, School of Electrical Engineering (EES), Signal Processing.ORCID iD: 0000-0003-2298-6774
2006 (English)In: 2008 IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, IEEE , 2006, 1-5 p.Conference paper (Refereed)
Abstract [en]

In this paper, we consider the unclaimed sub-carriers that no user feeds back in an opportunistic OFDMA system with a per sub-carrier power constraint. Unclaimed sub-carriers appear in OFDMA systems with reduced feedback, where the users concentrate the feedback on the sub-carriers with good channel quality. Here we propose and evaluate two ways to use these sub-carriers to improve the system performance. One approach is to transmit pilots symbols on the unclaimed sub-carriers. A second approach is to schedule users based on their feedback about adjacent sub-carriers. Simulation results show that for low to moderate channel rms delay spread, it is more advantageous to transmit data on unclaimed sub-carriers, even at a low rate, than to use them for additional pilot symbols. For high delay spreads however, transmitting pilots on the unclaimed sub-carriers gives higher system throughput.

Place, publisher, year, edition, pages
IEEE , 2006. 1-5 p.
, IEEE VTS Vehicular Technology Conference Proceedings, ISSN 1090-3038
Keyword [en]
OFDM modulation, frequency division multiple access, wireless channels, channel RMS delay, opportunistic OFDMA system, subcarrier power constraint
National Category
URN: urn:nbn:se:kth:diva-34907DOI: 10.1109/VTCF.2006.371ISI: 000260569401053ScopusID: 2-s2.0-34548832769OAI: diva2:428699
25th IEEE Instrumentation and Measurement Technology Conference Victoria, CANADA, MAY 12-15, 2008
QC 20110701Available from: 2011-07-01 Created: 2011-06-17 Last updated: 2012-01-23Bibliographically approved

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