Title :
Time and Frequency Synchronization for OFDMA Uplink System using the SAGE Algorithm
Author :
Lee, Jong-Ho ; Kim, Seong-Cheol
Author_Institution :
Sch. of Electr. Eng. & Comput. Sci., Seoul Nat. Univ.
fDate :
4/1/2007 12:00:00 AM
Abstract :
In this letter, we propose an iterative time and frequency synchronization scheme for orthogonal frequency-division multiple access (OFDMA) uplink system using the space-alternating generalized expectation-maximization (SAGE) algorithm. In the proposed scheme, the expectation step of the SAGE algorithm is intended to remove the multiple-access interference (MAI) caused by the other asynchronous users. Then, the maximization step is utilized in the timing and frequency offset estimation of each asynchronous user using the MAI-canceled signals. Simulation results present that the proposed scheme shows performance enhancement in the presence of multiple asynchronous users
Keywords :
expectation-maximisation algorithm; frequency division multiple access; frequency estimation; radio links; radiofrequency interference; synchronisation; MAI; OFDMA uplink system; SAGE algorithm; frequency offset estimation; frequency synchronization; multiple-access interference; orthogonal frequency-division multiple access; space-alternating generalized expectation-maximization; time synchronization; Frequency estimation; Frequency synchronization; Interchannel interference; Iterative algorithms; Machine assisted indexing; Multiple access interference; OFDM; Time domain analysis; Timing; Wireless communication;
Journal_Title :
Wireless Communications, IEEE Transactions on
DOI :
10.1109/TWC.2007.348309
