wlanhtltfchanneLestimate
使用HT-LTF的通道估计
Description
Examples
使用HT-LTF估算SISO通道
通过使用高吞吐量长训练场,估计和绘制HT混合格式通道的通道系数。
Create an HT format configuration object. Generate the corresponding HT-LTF based on the object.
CFG=wlanHTConfig; txSig = wlanHTLTF(cfg);
Multiply the transmitted HT-LTF signal by 0.2 + 0.1i and pass it through an AWGN channel. Demodulate the received signal.
rxsig = awgn(txsig*(0.2+0.1i),30);demodsig = wlanhtltfdemodulate(rxsig,cfg);
Estimate the channel response using the demodulated HT-LTF.
est = wlanHTLTFChannelEstimate(demodSig,cfg);
绘制通道估计。
散点图(EST)网格
通道估计与复杂通道乘数匹配。
Estimate MIMO Channel Using HT-LTF
通过使用高吞吐量长训练场来估计2x2 MIMO通道的通道系数。恢复HT-DATA字段并确定位错误的数量。
Create an HT-mixed format configuration object for a channel having two spatial streams and four transmit antennas. Transmit a complete HT waveform.
cfg = wlanhtconfig('NumTransmitAntennas',,,,2,,,,...'NumSpaceTimeStreams',,,,2,,,,'MCS',11);txpsdu = randi([0 1],8*cfg.psdulength,1);txwaveform = wlanwaveformgenerator(txpsdu,cfg);
通过2x2 TGN通道传递传输波形。
tgnchan = wlantgnChannel('采样率',,,,20e6,...'NumTransmitAntennas',,,,2,,,,...'numReceiveAntennas',,,,2,,,,...'LargeScaleFadingEffect',,,,“路径和阴影”);rxWaveformNoNoise = tgnChan(txWaveform);
创建具有噪声功率的AWGN频道,nVar
,对应于一个接收器9分贝的噪音figure. The noise power is equal toktbF, 在哪里kis Boltzmann's constant,t是环境噪声温度(290k),b是带宽(20 MHz),并且F是噪声图(9 dB)。
nvar = 10^(( - 228.6 + 10*log10(290) + 10*log10(20e6) + 9)/10);awgnchan = comm.awgnchannel('noisemethod',,,,'方差',,,,...'方差',,,,nVar);
将信号通过AWGN通道。
rxWaveform = awgnChan(rxWaveformNoNoise);
确定HT-LTF的索引。从接收的波形中提取HT-LTF。解码HT-LTF。
indLTF = wlanFieldIndices(cfg,'HT-LTF');rxltf = rxwaveform(indltf(1):indltf(2),:);ltfdemodsig = wlanhtltfdemodulate(rxltf,cfg);
Generate the channel estimate by using the demodulated HT-LTF signal. Specify a smoothing filter span of three subcarriers.
chEst = wlanHTLTFChannelEstimate(ltfDemodSig,cfg,3);
从接收的波形中提取HT-DATA字段。
inddata = wlanfieldindices(CFG,'ht-data');rxdatafield = rxwaveform(inddata(1):inddata(2),:);
恢复数据并验证是否没有发生任何位错误。
rxpsdu = wlanhtdataRecover(rxdatafield,胸部,nvar,cfg);numerrs = biterr(txpsdu,rxpsdu)
numErrs = 0
输入参数
Demodsig
-Demodulated HT-LTF signal
3-D阵列
解调的HT-LTF信号,指定为n英石-by-n符号-by-nr大批。n英石是被占领子载体的数量,n符号是HT-LTF OFDM符号的数量,并且是nr是接收天线的数量。
数据类型:双倍的
复杂的数字支持:金宝app是的
CFG
-Configuration information
wlanHTConfig
目的
Configuration information, specified as awlanHTConfig
目的。
span
-过滤器跨度
积极的奇数整数
过滤器跨度of the frequency smoothing filter, specified as an odd integer. The span is expressed as a number of subcarriers.
笔记
如果相邻的子载波高度相关,则频率平滑将导致显着降低噪音。但是,在高度频率的选择通道中,平滑可能会降低通道估计的质量。
数据类型:双倍的
输出参数
chEst
-Channel estimate
3-D阵列
时空流和接收天线的所有组合之间的渠道估计,返回n英石-by-(nsts+nESS)-by-nr大批。n英石是被占领子载体的数量,nsts是时空流的数量。nESSis the number of extension spatial streams.nr是接收天线的数量。Data and pilot subcarriers are included in the channel estimate.
数据类型:双倍的
复杂的数字支持:金宝app是的
更多关于
ht-ltf
高吞吐量长训练场(HT-LTF)位于HT-STF和HT混合数据包的数据字段之间。
如IEEE第19.3.9.4.6节所述®Std 802.11™-2016, the receiver can use the HT-LTF to estimate the MIMO channel between the set of QAM mapper outputs (or, if STBC is applied, the STBC encoder outputs) and the receive chains. The HT-LTF portion has one or two parts. The first part consists of one, two, or four HT-LTFs that are necessary for demodulation of the HT-Data portion of the PPDU. These HT-LTFs are referred to as HT-DLTFs. The optional second part consists of zero, one, two, or four HT-LTFs that can be used to sound extra spatial dimensions of the MIMO channel not utilized by the HT-Data portion of the PPDU. These HT-LTFs are referred to as HT-ELTFs. Each HT long training symbol is 4 μs. The number of space-time streams and the number of extension streams determines the number of HT-LTF symbols transmitted.
IEEE STD 802.11-2012的表19-12、19-13和90-14在这里复制。
nsts 决心 |
nHTDLTF 决心 |
nHTELTF 决心 |
|||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
表19-12定义了时空流的数量(nsts)基于空间流的数量(nSS)来自MCS和STBC领域。 |
table 19-13 defines the number of HT-DLTFs required for thensts。 |
表19-14定义了扩展空间流数量所需的HT-teltf数量(nESS)。nESS在ht-sig中定义2。 |
|||||||||||||||||||||||||||||||||||||||||||||||
|
|
|
其他约束包括:
nHTLTF=nHTDLTF+nHTELTF≤ 5。
nsts+nESS≤ 4。
Whennsts= 3,,,,nESScannot exceed one.
IfnESS= 1什么时候nsts= 3然后nHTLTF= 5。
references
[1] IEEE Std 802.11™-2012 IEEE Standard for Information technology — Telecommunications and information exchange between systems, Local and metropolitan area networks — Specific requirements — Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.
[2] Perahia,E。和R. Stacey。下一代无线LAN:802.11N和802.11ac。第二版,英国:剑桥大学出版社,2013年。
扩展功能
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
版本历史记录
1IEEE Std 802.11-2012 Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.
matlabコマンド
Matlabコマンドコマンドにするがクリックされまし。。
matlabコマンドコマンドに入力しててください。。。。ブラウザー
Select a Web Site
选择一个网站以获取可用的翻译内容,并查看本地事件和优惠。根据您的位置,我们建议您选择:。
You can also select a web site from the following list:
如何获得最佳网站性能
选择中国网站(中文或英语)以获得最佳场地性能。其他Mathworks乡村网站未针对您所在的访问进行优化。
Americas
- América Latina(Español)
- Canada(English)
- United States(English)