Title :
Time and frequency synchronization for uplink OFDM-CDMA
Author :
Kan Zheng ; Lin Huang ; Maomao Chen ; Wenbo Wang
Author_Institution :
Sch. of Telecommun. Eng., Beijing Univ. of Posts & Telecommun., China
Abstract :
A novel OFDM-CDMA system, which merges the advantages of OFDMA and CDMA to minimize multiple access interference and is less vulnerable to asynchronism among users, becomes more suitable for uplink transmission. The paper presents a simple time and frequency synchronization method for uplink OFDM-CDMA. Symbol timing is achieved by making use of the good correlation property of training sequences that are distinguished, not only in the frequency domain, but also in the code domain. Frequency offsets are estimated using the maximum likelihood (ML) principle. Simulation results illustrate the high accuracy and efficiency of the proposed estimation algorithms.
Keywords :
OFDM modulation; code division multiple access; frequency division multiple access; frequency estimation; maximum likelihood estimation; minimisation; mobile radio; radiofrequency interference; synchronisation; timing; OFDMA; correlation property; frequency estimation; frequency offset estimation; frequency synchronization; maximum likelihood estimation; mobile communications; multiple access interference; symbol timing; time synchronization; training sequences; uplink OFDM-CDMA; Downlink; Fading; Frequency estimation; Frequency synchronization; Gold; Interference; Multiaccess communication; Multicarrier code division multiple access; OFDM; Timing;
Conference_Titel :
Communications, Circuits and Systems, 2004. ICCCAS 2004. 2004 International Conference on
Conference_Location :
Chengdu
Print_ISBN :
0-7803-8647-7
DOI :
10.1109/ICCCAS.2004.1346097
