基于多速率星地环路的SC-CFDMA上行符号同步方法

doi:10.11959/j.issn.1000-436x.2015298

摘要/Abstract

摘要：

单载波码分与频分多址(SC-CFDMA，single carrier code and frequency division multiple access)体制要求符号定时精确至码片级，同步难度高于普通体制。为此提出一种多速率星地闭环同步方法，通过适当提升部分环路元件的控制速率，在环路非采样点上延续闭环控制，从而提高对用户运动速度的适应能力。推导了控制速率提升后相关元件及环路的状态空间方程，进行了Matlab软件仿真，结果表明，即使在高轨卫星通信场景下，所提方法也能将多个超音速用户之间的SC-CFDMA上行符号定时偏差同步至码片宽度内，保证链路畅通。

关键词: 卫星通信, SC-FDMA, 符号同步, 多速率, 闭环控制

Abstract:

SC-CFDMA(single carrier code and frequency division multiple access) system,whose synchronization is more difficult than that of common orthogonal multi-carrier systems,requires the symbol synchronization to achieve a chip-level precision.Therefore,a synchronization method based on multi-rate satellite-ground loop is proposed.This method extends the closed-loop control on the non-sampling points of the loop through raising the control rates of some loop components,so as to promote the adaptability to users with different speeds.Besides,the state-space equations of the loop and related components are derived.The Matlab simulation results show that,even in GEO satellite system,the synchronization method proposed can adjust the SC-CFDMA uplink symbol timing errors between several supersonic users within chip-level duration,thus providing stable communication.

Key words: satellite communication, SC-FDMA, symbol synchronization, multi-rate, closed-loop control

丁丹,程乃平,廖育荣. 基于多速率星地环路的SC-CFDMA上行符号同步方法[J]. 通信学报, 2015, 36(Z1): 181-187.

Dan DING,Nai-ping CHENG,Yu-rong LIAO. SC-CFDMA uplink symbol synchronization method based on multi-rate satellite-ground loop[J]. Journal on Communications, 2015, 36(Z1): 181-187.

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类别	参数	取值
系统基本参数	总子载波数N	1 024
	子载波集大小M	64
	训练序列类型	Gold码
	卫星类型	GEO透明转发卫星
系统误差来源	卫星摄动影响	1 m/s
	本地钟源漂移影响	1 ns/s
	电离层闪烁影响	10 ns/s
	A/D采样处信噪比	-27～-20 dB
影响性能的参数	子载波集内用户数	4个、8个、16个
	控制速率提升倍数	2⁹、2¹⁰、2¹¹
	训练序列长度	511 bit、1 023 bit
	用户终端运动速度	1马赫、4马赫、8马赫
	系统采样速率/伪码速率	20.48 MHz、40.96 MHz