Frequency Estimators for MIMO-OFDM and OFDM-CDMA Systems
碩士 === 國立交通大學 === 電信工程系所 === 92 === For orthogonal frequency division multiplexing (OFDM) based systems, a carrier frequency offset (CFO) existed between the transmitter and receiver will destroy the orthogonality of the subcarrier and degrades the performance. In this thesis, we extend both Moose&#...
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| Format: | Others |
| Language: | en_US |
| Published: |
2004
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| Online Access: | http://ndltd.ncl.edu.tw/handle/91873413059214504141 |
| Summary: | 碩士 === 國立交通大學 === 電信工程系所 === 92 === For orthogonal frequency division
multiplexing (OFDM) based systems, a carrier frequency offset
(CFO) existed between the transmitter and receiver will destroy
the orthogonality of the subcarrier and degrades the performance.
In this thesis, we extend both Moose's and Yu's maximum likelihood
CFO estimation algorithm for multiple transmit and multiple
receive MIMO-OFDM systems. OFDM Code-Divison Multiple-Access
(OFDM-CDMA) have been one of the candidates for the next
generation of mobile broadband communication. In an uplink, each
user's transmitted signal suffers from asynchronous transmission
and independent frequency selective channel and the different
frequency offsets of each active user. We present a CFO estimation
algorithm to be used in a asynchronous uplink and frequency
selective channels for OFDM-CDMA systems. The algorithm estimates
the CFO of the desired user and eliminates the multiuser
interference (MUI). The CFO estimate is obtained by searching the
value which maximizes the output energy of the minimum output
energy (MOE) criterion. However, the CFO estimate requires an
exhaustive search over the entire uncertainty range. We convert
the min/max search into polynomial rooting problem.
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