Paper Info
Title
Carrier Frequency Offset Estimation for Multi-User MIMO OFDM Uplink Using CAZAC Sequences
Abstract
In the uplink of multi-user multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems, there are multiple carrier frequency offsets (CFO's) from the multiple users. In this paper, we study algorithms to estimate these multiple CFO values. We first derive the maximum likelihood (ML) estimator and show that the complexity of the ML estimator increases exponentially with the number of users so that the estimator is not suitable for practical implementations. To reduce the complexity, we propose a sub-optimal algorithm using constant amplitude zero autocorrelation (CAZAC) sequences. The complexity of the proposed method increases only linearly with the number of users. Using computer simulations, we compare the performance using CAZAC training sequences with that using the m sequence and the short training field (STF) of the IEEE 802.11n systems. The results show that in the low to medium SNR regions, the performance using CAZAC sequences is very close to the single-user Cramer-Rao bound. For high SNR regions, an error floor exists due to multiple access interference (MAI). The error floor using CAZAC sequences is more than 10 times smaller compared to the error floor using the other two sequences.
Year
DOI
Venue
2009
10.1109/WCNC.2009.4917620
WCNC
Keywords
Field
DocType
error floor,cazac training sequence,multiple access interference,cazac sequence,multiple cfo value,frequency estimation,multiple output,ofdm modulation,orthogonal frequency division multiplexing,multiuser mimo ofdm uplink,multi-access systems,sequences,computational complexity,ml estimator increases exponentially,mimo communication,multiple user,multi-user multiple input,multiple carrier frequency offset,multiple input multiple output system,sub-optimal algorithm,carrier frequency offset estimation,maximum likelihood estimator complexity,correlation methods,constant amplitude zero autocorrelation sequence,maximum likelihood,maximum likelihood estimation,estimation,computer simulation,ofdm,signal to noise ratio,cramer rao bound,transmitters,mimo,fading
Multi-user MIMO,Computer science,Control theory,Carrier frequency offset,Signal-to-noise ratio,Algorithm,MIMO,Real-time computing,Interference (wave propagation),Orthogonal frequency-division multiplexing,Estimator,Telecommunications link
Conference
ISSN
ISBN
Citations 
1525-3511 E-ISBN : 978-1-4244-2948-6
978-1-4244-2948-6
4
PageRank 
References 
Authors
0.53
12
3
Name
Order
Citations
PageRank
Yan Wu1436.99
Samir Attallah26212.45
J. W. M. Bergmans37612.54