Carrier Frequency Offset Estimator Based on Unique Word Cross-correlation Riga Technical University Latvia Arturs Aboltins
Dec 28, 2015
Carrier Frequency Offset Estimator Based on Unique Word Cross-correlation
Carrier Frequency Offset Estimator Based on Unique Word Cross-correlationRiga Technical UniversityLatviaArturs AboltinsContentsCommunication system description;Carrier frequency offset (CFO);Estimation algorithms;Demonstration at work;Performance characteristics;
Communication system with block-wise time domain signal
Possible contents of the data fieldComplex-valued (QAM, QPSK, BPSK, ) samplesDiscrete unitary transform of samplesDiscrete Fourier Transform (OFDM-like)Parametric transform
Parametric communication systemsPossible contents of UW fieldFor frequency offset estimation any determined (non-random) sequence can be used.
Since the same sequences are reused for other tasks (channel estimation, timing estimation), Chu-Zadoff sequences are chosenUp conversion
Carrier frequency
Down conversion
Impact of carrier frequency offset
CFO estimation methodsNon-data aided (blind)Data aided (auto-correlation AC)Data directed (cross correlation - XC)
Auto correlation
problemPopular in OFDM for fractional CFO estimationk
Cross correlation
kProposed XC based algorithms1. Average increment based method
3. Method for CAZAC sequences
2. Least squares based method
Synchronizer at work
SNR characteristics
AWGN channelFrequency selective channelDependence on CFO