Logic Analyzer System object · 4 无线标准的演化 * *Although ETSI the European standardization body started GSM, later ETSI and other standard bodies formed 3GPP and 3G and

1 © 2014 The MathWorks, Inc.

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4G LTE 轻松入门

陈建平

MathWorks 中国

3

大纲

4G 综述

LTE 系统工具箱的应用 – 黄金参考模型

– 点到点链路级仿真

– 信号发生和分析

– 信号信息恢复

4G 系统的并行仿真加速

4

无线标准的演化

*

*Although ETSI the European standardization body started GSM, later ETSI and other standard bodies

formed 3GPP and 3G and 4G standards were developed globally by 3GPP. For a while a standard body

known as 3GPP2 competed with 3GPP and developed North American 3G CDMA standards based on IS-95

but 3GPP2 finally dissolved in 2005

5

不同标准的峰值速率

Technology Theoretical peak data rate

(at low mobility)

GSM 9.6 kb/s

IS-95 14.4 kb/s

GPRS 171.2 kb/s

EDGE 473 kb/s

CDMA-2000 (1xRTT) 307 kb/s

WCDMA (UMTS) 1.92 Mb/s

HSDPA (Rel 5) 14 Mb/s

CDMA-2000 (1x-EV-DO) 3.1 Mb/s

HSPA+ (Rel 6) 84 Mb/s

WiMAX (802.16e) 26 Mb/s

LTE (Rel 8) 300 Mb/s

WiMAX (802.16m) 303 Mb/s

LTE-Advanced (Rel 10) 1 Gb/s

6

LTE 的演进

LTE (Release 8) 发布于2008 年

LTE (Release 9) 发布于2009年，基于R8做了微小的改动

LTE-Advanced = LTE-A = LTE Release 10 – 最大峰值速率 1Gbps

7

LTE 关键技术

基本接入方式

– Downlink: OFDMA

– Uplink: SC-FDMA

多天线 (MIMO) 技术

自适应技术

– 自适应调制和编码

– 自适应预编码

– 自适应MIMO

– 动态带宽分配

Turbo 码

8

OFDM

正交频分复用 – 多载波调制方案（基于 FFT 变换）

在每个子载波（窄带）中独立传输数据特点

– 抗多径衰落的健壮性

– 低复杂度的频域均衡器

G(ω)H(ω)

1

ω

9

MIMO

Multiple Input Multiple Output

使用多个发射和接收天线

Multiple Input Multiple Output

h1,1

h1,2

h4,4

h2,1

X Y

Y = H*X + n

H=ℎ11 ℎ12 ℎ13 ℎ14ℎ21 ℎ22 ℎ23 ℎ24ℎ31 ℎ32 ℎ33 ℎ34ℎ41 ℎ42 ℎ43 ℎ44

信道

10

自适应技术

自适应调制和编码

自适应预编码

自适应MIMO

动态带宽分配

11

Turbo 码

LTE 标准的纠错码技术

性能：逼近信道容量（香

农界）

卷积码的演化

基于迭代译码

12

大纲

4G 综述






13

演示:

下行一致性测试

>> lteDLConformanceTestTool

Rx Tx Ch

14

LTE 系统工具箱

易用的高层模型

传输层信道函数

处理细节函数库

Scrambling

Precoding Resource

Mapping

Modulation

Layer

Mapping

Resource

Mapping

Modulation Scrambling

Complete PDSCH processing:

Encoding: ltePDSCH

Decoding: ltePDSCHDecode

Resource indices:

ltePDSCHIndices

Scrambling

ltePDSCHPRBS

Modulation

lteSymbolModulate

Demodulation

lteSymbolDemodulate

Layer Mapping

LteLayerMap

Layer Demapping

lteLayerDemap

Precoding

LteDLPrecode

Deprecoding

lteLayerDeprecode

Precoding Matrix Indication

ltePMISelect

ltePMIInfo

lteCSICodebook

15

标准兼容

通过和已有仪器产生的信号一致性测试 – Rohde & Schwarz

– Agilent

2009年开始被工业界采用 – Steepest Ascent

对现场采集的 LTE 信号成功解调

16

典型的应用场景

验证内部 LTE 物理层模型的黄金参考

完整的端到端链路级仿真

信号发生和分析

信号信息恢复

Transmitter

Test Waveform

Generation

17

1. 用于验证黄金参考模型

"We used LTE System Toolbox to validate our LTE baseband IP cores

and example design C models. This meant we could trust our own C

models matched the 3GPP specification and allowed us to verify our

RTL designs against the C models with confidence. Catching issues

early in simulation saved a lot of time later when it came to

hardware testing. The MATLAB environment allowed us to rapidly

assemble and run test cases."

Bill Wilkie, Director of Communications Signal Processing

(Europe), Xilinx.

"Steepest Ascent's LTE Toolbox gave us much valued confidence in

assessing our LTE physical layer performance. My team's decision to

use the capabilities of the LTE Toolbox as reference to validate our

LTE designs proved beneficial for risk reduction and

accelerating project milestones, a choice I would support again.“

18

用于验证黄金参考模型

目标

– 内部设计模型和外部参考模型的对照验证

特点 – 标准兼容的参考模型

– 不同层面的抽象底层 = 速率匹配、编码……

中层 = 传输信道……

优点 – 降低风险

– 早期验证

– 规格的双重独立确认

19

用于验证黄金参考模型 ——演示

简明的下行设置

容易嵌入到自己编写代码之中

Uplink example:

PUCCHMixedFormatsExample

20

2. 端到端的连路级仿真

"We rely on Steepest Ascent's LTE Toolbox for a variety of

project needs. One use is as a golden reference for our own

in-house simulator where the Toolbox's complete feature set

has allowed us to build industrial strength simulations rapidly

with guaranteed baseline requirements. Its extensible

design enables us to customise these models for our

own LTE research work. All this is made easier by the

great documentation and excellent product support."

21

端到端的连路级仿真

目标

– 设计和优化 LTE 系统的子集

特点 – 完整的经过验证的环境

– 已有的测试链路级性能的仿真模型吞吐率、BER、误帧率

优点

– 节约时间

– 容易维护

– 集中在需要修改的有价值的部分

22

% Perform frame synchronization

offset = lteDLFrameOffset(enb,rxWaveform);

rxWaveform = rxWaveform(1+offset:end,:); % Align to frame start

% Perform OFDM demodulation

rxGrid = lteOFDMDemodulate(enb,rxWaveform);

端到端的连路级仿真

——演示性能测试

信道均衡

23

3. 信号发生和分析

Antenna builder company

Initial response: The tool does too much

Second thought: We need additional test cases and the LTE

Toolbox provides more flexibility than is available from T&M

vendors

24

Transmitter

Test Waveform

Generation

信号发生和分析

目的

– 产生标准兼容的信号，比如用于测试天线或者放大器组件

特点

– 产生标准兼容的信号的高层工具

(lteRMCULTool,lteRMCDLTool,lteTestModelTool)

– 强大的分析能力 (EVM, ACLR, …)

优点

– 无需 LTE 专业知识

– 参数化和 MATLAB 带来的弹性

– 真实的测试组件和模型干扰的信号

Rx Tx Ch

25

信号发生和分析 Test Model Waveforms

>> lteTestModelTool

Standard-compliant

signal available in the

MATLAB workspace

Rx Tx Ch

TS 36.141

26

信号发生和分析 E-TM (TS 36.141)

% Generate test model waveform & populated resource grid

[waveform,tmgrid,config]=lteTestModelTool('1.1','5MHz');

Rx Tx Ch

Primary Synchronisation

Signals

Secondary

Synchronisation Signals

Broadcast Channel

Unused

Cell Specific Reference

Signals

Physical Control Format

Indicator Channel

Physical Downlink

Control Channel

Physical Downlink Shared

Channel

27

LTE 标准兼容的信号：信号发生和传输

• 配置和控制一起参数 Instrument Control Toolbox

• 在 MATLAB 中产生 LTE 基带信号

• 下载到通用信号发生仪

RF Signal Generator LAN/USB/GPIB

hDownloadAndPlayWaveformUsingN5172B.m

http://www.mathworks.com/products/instrument

28

▪ 输入 IQ 数据到 MATLAB

▪ 可视化分析

LAN/USB/GPIB

hCaptureIQUsingN9010A.m

Spectrum Analyzer

LTE 标准兼容的信号：信号识别和分析

29

在 VSA 中分析接收到的 LTE 波形

TS36.104 Table 6.5.2-1 EVM requirements

30

4. 信号信息的恢复

Defense company

We have used Steepest Ascent software to successfully

process the standards-based aspects of data produced

from live exercises. Based on the excellent performance of

the toolkit, we feel that our decision was correct and justified

31

4. 信号信息恢复

目标

– 从实际的 LTE 信号中提取信息

特点 – 同步和解调

– 诸如 MIB 和 SIB1 信号的提取

– 定位信息

优点

– 现成的解调能力

– 可扩展的基于 MATLAB 的解决方案

32

4. 信号信息恢复

——演示

依据输入信号自动同步

MIB 解调和控制信道

确认天线数和 PHICH 设置

搜索小区 ID 和定时

获取小区带宽

执行小区搜索……

执行信道估计……

MIB 译码……

33

LTE 系统工具箱

易用的高层模型

传输层信道函数

处理细节函数库

Scrambling

Precoding Resource

Mapping

Modulation

Layer

Mapping

Resource

Mapping

Modulation Scrambling

Complete PDSCH processing:

Encoding: ltePDSCH

Decoding: ltePDSCHDecode

Resource indices:

ltePDSCHIndices

Scrambling

ltePDSCHPRBS

Modulation

lteSymbolModulate

Demodulation

lteSymbolDemodulate

Layer Mapping

LteLayerMap

Layer Demapping

lteLayerDemap

Precoding

LteDLPrecode

Deprecoding

lteLayerDeprecode

Precoding Matrix Indication

ltePMISelect

ltePMIInfo

lteCSICodebook

34

粒度: 高层接口

基于图形用户界面

MATLAB 函数

信号发生器

35

粒度：中层接口

传输信道

36

粒度: 底层接口

Fine

Mid-level

PDSCH

37 37

LTE 系统工具箱支持：

Downlink Uplink

Transport Channels & Control Information

Transport Channels & Control Information

DL-SCH HI UL-SCH UCI

BCH CFI

DCI

Physical Channels and Signals Physical Channels and Signals

PDSCH PDCCH PUSCH SRS

PBCH Reference Signals PUCCH PRACH

PCFICH PSS - SSS DRS (PUCCH)

PHICH DRS (PUSCH)

38

大纲

4G 综述






39

并行 for 循环 (parfor)

<<初始化>>

p = parpool

parfor i = 1:numel(SNRdB)

<<PDSCH 算法>>

end

<< 后处理 >>

delete(p)

串行并行

<<初始化>>

for i = 1:numel(SNRdB)

<<PDSCH 算法>>

end

<< 后处理 >>

40

多核工作站加速 LTE 仿真 Parallel Computing Toolbox

MATLAB

Desktop (Client)

Local

桌面计算机

核数计算时间

(小时) 加速比

1 30.7 基线

2 15.6 1.97x

4 7.9 3.87x

8 4.0 7.65x

PDSCH 一致性测试（104子帧）

41

计算机集群加速仿真 MATLAB Distributed Computing Server

MATLAB

Desktop (Client)

Local

桌面计算机

Cluster

计算机集群

Scheduler


Q & A

Documents

Logic Analyzer System object · 4 无线标准的演化 * *Although ETSI the European standardization body started GSM, later ETSI and other standard bodies formed 3GPP and 3G and