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
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
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
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
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
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
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
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)
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