A Caltech Library Service

Scattered Pilots and Virtual Carriers Based Frequency Offset Tracking for OFDM Systems: Algorithms, Identifiability, and Performance Analysis

Gao, Feifei and Cui, Tao and Nallanathan, Arumugam (2008) Scattered Pilots and Virtual Carriers Based Frequency Offset Tracking for OFDM Systems: Algorithms, Identifiability, and Performance Analysis. IEEE Transactions on Communications, 56 (4). pp. 619-629. ISSN 0090-6778. doi:10.1109/TCOMM.2008.060050.

See Usage Policy.


Use this Persistent URL to link to this item:


In this paper, we propose a novel carrier frequency offset (CFO) tracking algorithm for orthogonal frequency division multiplexing (OFDM) systems by exploiting scattered pilot carriers and virtual carriers embedded in the existing OFDM standards. Assuming that the channel remains constant during two consecutive OFDM blocks and perfect timing, a CFO tracking algorithm is proposed using the limited number of pilot carriers in each OFDM block. Identifiability of this pilot based algorithm is fully discussed under the noise free environment, and a constellation rotation strategy is proposed to eliminate the c-ambiguity for arbitrary constellations. A weighted algorithm is then proposed by considering both scattered pilots and virtual carriers. We find that, the pilots increase the performance accuracy of the algorithm, while the virtual carriers reduce the chance of CFO outlier. Therefore, the proposed tracking algorithm is able to achieve full range CFO estimation, can be used before channel estimation, and could provide improved performance compared to existing algorithms. The asymptotic mean square error (MSE) of the proposed algorithm is derived and simulation results agree with the theoretical analysis.

Item Type:Article
Related URLs:
URLURL TypeDescription
Additional Information:© Copyright 2008 IEEE. Reprinted with permission. Paper approved by Y. Li, the Editor for Wireless Communication Theory of the IEEE Communications Society. Manuscript received January 22, 2006; revised January 06, 2007 and February 13, 2007. [Posted online: 2008-04-15] The authors would like to thank the anonymous reviewers for their critical comments that greatly improved this paper.
Subject Keywords:Carrier frequency offset, OFDM, CFO ambiguity, constellation rotation, IEEE 802.11a
Issue or Number:4
Record Number:CaltechAUTHORS:GAOieeetc08
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10425
Deposited By: Archive Administrator
Deposited On:04 May 2008
Last Modified:08 Nov 2021 21:07

Repository Staff Only: item control page