Maximum-Likelihood Synchronization and Channel Estimation for OFDMA Uplink

Transmissions

Chi-En LiChi-En LiDirected by Prof. Jung-Shan LinDirected by Prof. Jung-Shan Lin

Graduate Institute ofGraduate Institute of Communication EngineeringCommunication EngineeringNational Chi Nan UniversityNational Chi Nan University

12/ 11/ 200812/ 11/ 2008

OutlineOutline

• System model and signal model

• CFO estimation

• Estimation of the timing offsets and channel • Simulation

• Conclusion

System modelSystem model

Signal modelSignal model

CFO estimationCFO estimation

• Alternating-Projection Frequency Estimator (APFE)

CFO estimationCFO estimation

CFO estimationCFO estimation

CFO estimationCFO estimation

CFO estimationCFO estimation• Approximate Alternating-Projection Frequency Estimator

(AAPFE)

Estimation of the timing offsets and channel responses

Estimation of the timing offsets and channel responses

Simulation parameters• Operation = 5GHz• Signal bandwidth = 20MHz• L = 8• Ng = 28• QPSK• N = 128 • CFO ~ [-0.32 , 0.32]• Delay ~ [0 , 20] (sample period)• HIPERLAN/2 channel model

Simulation

Simulation

Simulation

Simulation

ConclusionConclusion

• APFE and AAPFE

• Simulation

The M value The number of user The signal power of user

ReferenceReference

• Maximum-likelihood synchronization and channel estimation for OFDMA uplink transmissionsPun, M.-O.; Morelli, M.; Kuo, C.-C.J.;Communications,

IEEE Transactions on Volume 54, Issue 4, April 2006 Page(s):726 - 736 Digital Object Identifier 10.1109/TCOMM.2006.873093