基于判決反饋的OFDM載波頻率同步環(huán)路
A Decision-Directed OFDM Carrier Frequency Synchronization Loop
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摘要: 對OFDM系統(tǒng)中一種基于接收時域信號重構(gòu)的載波頻率盲估計算法進行了進一步的研究，分析了在這種方法中影響估計精度的4個方面的因素。為了減少載波頻率估計的剩余誤差，通過在頻率補償時增加反饋因子，提出了一種基于判決反饋的載波頻率同步環(huán)路結(jié)構(gòu)。通過調(diào)整同步環(huán)路的環(huán)路增益，可以獲得更好的頻率跟蹤性能。如果信噪比達到9dB，即使存在較大的頻率漂移，剩余頻偏也被限制在子載波間隔的1%以內(nèi)。
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關(guān)鍵詞:
- OFDM 系統(tǒng);載波頻率偏移;判決反饋;跟蹤;多徑信道
Abstract: Further investigation is given to a kind of carrier frequency offset (CFO) blind estimation algorithm based on time domain received signal reconstruction in OFDM systems, and the four aspects that affect the estimation accuracy are analyzed. For minimizing the residual carrier frequency offset, a kind of decision-directed carrier frequency synchronization loop is given by introducing a feedback factor into the frequency compensation. Better carrier frequency tracking performance can be gotten by adjusting the loop gain. The residual frequency offset can be restricted within 1% of the carrier spacing even if lager frequency drift exists, if bit SNR reaches 9dB. -
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