3GPP通道下的少量循環前綴正交時頻間距調變

Abstract

在低地球軌道(LEO)衛星通訊中，傳輸受到都卜勒效應的影響。正交時頻間距(OTFS)調變技術被用來應對延遲-都卜勒(DD)通道的挑戰。本文在具有少量循環前綴(CP)的P-路徑雙重分散性通道上建立了一個MxN OTFS系統，其中僅在OTFS訊息的開頭添加一組循環前綴。首先我們基於以往的研究推導了延遲-都卜勒通道中時域的正確輸入輸出關係，並將該關係用簡單的矩陣形式表示。接著，我們將3GPP標準中的通道模型轉換為延遲-都卜勒通道模型，轉換過程中使用了真實衛星傳輸的實際數據和CDL-A模型。此外，我們提出了一個清楚且正確的通道估計方法。最後，我們通過模擬進行了通道估計和資料偵測，同時在傳輸中引入了導頻。

In Low Earth Orbit (LEO) satellite communications, transmissions are affected by the Doppler effect. The Orthogonal Time Frequency Space (OTFS) modulation technique is employed to address delay-Doppler channel challenges. This paper models an MxN OTFS system over a P-path doubly dispersive channel with a reduced cyclic prefix (CP), where only a single CP is added at the beginning of the OTFS frame. First, we derive the corrected input-output relation in the time domain for delay-Doppler (DD) channels based on previous studies and express this relation in a simple matrix form. Next, we convert the channel model in the 3GPP standard to the DD channel model, utilizing practical data from real satellite transmissions and CDL-A model. Moreover, we propose a clear and accurate channel estimation method. Finally, we perform channel estimation and data detection through simulation, introducing pilots into the transmission.