CAJ | 학술논문

由于发射和接收机振荡器的不稳定或／和信道的多普勒效应，使载波同步与补偿成为QAM信号接收的关键环节。针对非协作通信中各类载波同步算法只能校正较小的频率偏移的局限，根据QAM信号的基本特点，利用传输符号的统计独立特性，提出了一种新的数字载波频率估计方法。该算法采用开环方式，不需要导频数据，可以估计较大的频率偏移；没有反馈环路，复杂度低，实现起来比较简单。同时，该算法作适当改进，可以直接用于载波的估计。计算机仿真结果表明：该算法可以较好地对各种QAM信号中存在的较大频率偏移进行估计并做补偿；适＂-B改进后可以直接用于估计载波频率，估计效果良好有效。
유우발사화접수궤진탕기적불은정혹／화신도적다보륵효응，사재파동보여보상성위QAM신호접수적관건배절。침대비협작통신중각류재파동보산법지능교정교소적빈솔편이적국한，근거QAM신호적기본특점，이용전수부호적통계독립특성，제출료일충신적수자재파빈솔고계방법。해산법채용개배방식，불수요도빈수거，가이고계교대적빈솔편이；몰유반궤배로，복잡도저，실현기래비교간단。동시，해산법작괄당개진，가이직접용우재파적고계。계산궤방진결과표명：해산법가이교호지대각충QAM신호중존재적교대빈솔편이진행고계병주보상；괄＂-B개진후가이직접용우고계재파빈솔，고계효과량호유효。
Carrier frequency recovery and compensation are of the key factors in digital QAM receivers due to transceiver oscillator instabilitiy and/or channel Doppler effects. There are some carrier estimation algorithms for the non-cooperative communication environment, but they are all adopted when carrier frequency offset is small comparing with the symbol rate. In this paper, a carrier estimation algorithm has been proposed, which is non-data-aided and can be implemented in digital form. Because of its open-loop structure, the proposed algorithm is very simple and easy to be implemented. Using the property of the transmitted symbols, its estimation time is independent of the frequency and the estimation range is large, on the order of the symbol rate. The proposed estimator can be improved to adap the estimation of the carrier frequency directly. The simulation results show that the proposed algorithm can estimate the carrier frequency offset, while the a- mending algorithm can also be used to estimate the carrier frequency directly, and the performance is very good for all QAM signals.