減緩干擾的序列應用於多基地台同步

Abstract

位於一個大型基地台和毫微蜂巢型基地台的重疊網路內，多基地台的干擾會造成同步更加困難相較於在一般單一基地台環境，因此如何減少多基地台的干擾是很重要的。此研究中，我們設計了一組同步序列，不僅具有良好的自相關特性並且更加能抵抗多基地台的干擾。我們模擬結果顯示，藉由設計的同步序列，多基地台的干擾能被足夠減緩，以及基地台偵測能被改善。除此之外，由於正交分頻多工系統對於載波頻率偏差很敏感，所以在多基地台環境內，載波頻率偏差的估測和補償也是很重要的。模擬結果顯示，採用建議的載波頻率偏差估測方法，我們的同步序列比長期演進規格中的第一同步序列具有更顯著良好載波頻率偏差的估測準確度。

In a macro/femtocell overlay network, multi-cell interference (MCI) would make synchronization more difficult than that in conventional single-cell environments. Therefore how to reduce the MCI is crucial. In this research we propose a set of synchronization sequences which have not only good autocorrelation property but also more robust to the MCI. Our simulation results show that the MCI is sufficiently mitigated by applying the proposed synchronization sequences as well as the cell detection performance is improved. Moreover, since OFDM system is sensitive to the carrier frequency offset (CFO), CFO estimation and compensation is also important in multi-cell scenario. Simulation results depict that, with the proposal CFO estimation method, our propose sequences have significantly better CFO detection accuracy than the primary sequence used in LTE standard.