主要内容

lteFadingChannel

Multipath fading MIMO channel propagation conditions

collapse all in page

Syntax

[rx,info] = lteFadingChannel(model,tx)

描述

example

[rx,info] = lteFadingChannel(model,tx)filters waveformtxthrough the Rayleigh fading channel parameterized bymodel。The function returns channel output waveformrxand channel model informationinfo。有关此功能实施的多输入多输出（MIMO）多径褪色通道的信息，请参见Fading Channel Model Delay。

例子

collapse all

Open Live Script

Define the channel configuration structure.

model = struct(DelayProfile="EPA",NRxAnts=1,。。。DopplerFreq = 5,MIMOCorrelation="Low",。。。Seed=1,InitPhase="Random",ModelType=“ gmeds”,。。。NTerms=16,NormalizeTxAnts="On",。。。NormalizePathGains="On"）；

Define the transmission waveform configuration structure, initialized to reference measurement channel (RMC) R.10 and one subframe.

rmc = lteRMCDL("R.10"）；rmc.totsubframes = 1;

Generate ten subframes, one subframe at a time, by following these steps.

  1. Definedelay, which accounts for a combination of implementation delay and channel delay spread.

  2. Set the subframe number and initialize the subframe start time, allocating 1 ms per subframe.

  3. Generate a transmit waveform.

  4. 初始化发射天线的数量和波形采样速率。

  5. Send the waveform through the channel. Appenddelay0之前生成的波形通道filtering.

delay = 25;forsubframeNumber = 0:9 rmc.NSubframe = mod(subframeNumber,10); model.InitTime = subframeNumber/1000; [waveform,txGrid,info] = lteRMCDLTool(rmc,[1; 0; 1; 1]); numTxAnt = size(waveform,2); model.SamplingRate = info.SamplingRate; tx = [waveform; zeros(delay,numTxAnt)]; [rx,info] = lteFadingChannel(model,tx);end
Open Live Script

Transmit two consecutive frames over a fading channel while maintaining continuity in the fading process between the end of the first frame and the beginning of the second frame.

Initialize a resource grid to RMC R.10 and generate a transmit waveform for the first frame.

rmc = lteRMCDL("R.10"）；[waveform,~,info] = lteRMCDLTool(rmc,[1; 0; 1]);

Initialize a propagation channel configuration structure and set the start time for the first frame.

model = struct(DelayProfile="EPA",NRxAnts=1,。。。DopplerFreq=5,MIMOCorrelation="Low",。。。SamplingRate=info.SamplingRate,Seed=1,。。。InitPhase="Random",ModelType=“ gmeds”,。。。NTerms=16,NormalizeTxAnts="On",。。。NormalizePathGains="On",InitTime=0); nTxAnts = size(waveform,2);

Definedelayand append zeros to the generated waveform prior to channel filtering.

delay = 25; tx = [waveform; zeros(delay,nTxAnts)];

Filter the first frame through the channel.

[rx1,info1] = lteFadingChannel(model,tx);

Update the frame number, and then generate a transmit waveform for the second frame with the start time set to 10 ms.

model.NFrame = 1; [waveform,txGrid] = lteRMCDLTool(rmc,[1; 0; 1]); tx = [waveform; zeros(delay,nTxAnts)]; model.InitTime = 10e-3;

通过第二帧穿过通道。

[rx2,info2] = lteFadingChannel(model,tx);

Input Arguments

collapse all

多路径褪色通道模型，指定为包含这些字段的结构。

Field 必需的or Optional Values 描述 Dependencies
NRxAnts 必需的

Positive integer

 Number of receive antennas Not applicable
微相关 必需的

"Low",“中等的”,"UplinkMedium","High","Custom"

Correlation between UE and eNodeB antennas.

  • 要指定天线之间没有相关性，请将此字段设置为"Low"

  • To specify the correlation level defined in Annex B.2.3.2 of TS 36.101[1], which applies to tests defined in TS 36.101, set this field to“中等的”

  • 指定附件B.5.2中定义的相关水平36.104[2], which applies to tests defined in TS 36.104, set this field to"UplinkMedium"

  • 要指定天线之间的强相关性，请将此字段设置为"High"

  • To specify correlation between antennas in theTxCorrelationMatrixandRxCorrelationMatrixfields, set this field to"Custom"。

Note

Because the"Low"and"High"correlation levels are the same for uplink and downlink, they apply to tests defined in TS 36.101 and TS 36.104.
NormalizeTxAnts Optional

"On"（默认）,"Off"

Transmit antenna number normalization. To normalize the output waveform by1/√P, wherePis the number of transmit antennas, set this field to"On"。发射天线数量的归一化确保发射天线的数量不会影响每个接收天线的输出功率。
DelayProfile 必需的

"EPA","EVA",“ etu”,"Custom","Off"

延迟配置文件模型。有关更多信息，请参阅Propagation Channel Models。

To completely switch off fading and implement a MIMO channel model that is constant in time and frequency, set this field to"Off"。In this case, the number of columns in theininput specifies the number of transmit antennas, theNRxAntsfield specifies the number of receive antennas, and the微相关field specifies the MIMO correlation. The temporal part of the model for each link between transmit and receive antennas consists of a single path with zero delay and constant unit gain. This setting does not implement the channel model defined in Annex B.1 of[1]。
DopplerFreq 必需的 非负标量 Maximum Doppler frequency in Hz 要启用这些字段，请设置DelayProfile字段到a value other than"Off"。
SamplingRate 必需的 正标量 Input waveform sampling rate
停赛时间 必需的 非负标量

Fading process time offset in seconds
NTerms Optional

16（默认）

功率2

用于褪色路径建模的振荡器数量
ModelType Optional

“ gmeds”（默认）,"Dent"

Rayleigh fading model type.

  • To model Rayleigh fading by using the generalized method of exact Doppler spread (GMEDS) described in[4], set this field to“ gmeds”。

  • 通过使用修改的Jakes褪色模型来模拟瑞利褪色[3], set this field to"Dent"。

Note

Setting this field to"Dent"is not recommended. Use“ gmeds”instead.
NormalizePathGains Optional

"On"（默认）,"Off"

Model output normalization.

  • To normalize therxoutput such that the average power is unity, set this field to"On"。

  • To normalize therxoutput such that the average output power is the sum of the powers of the taps of the delay profile, set this field to"Off"。
InitPhase Optional

"Random"（默认）

标量

4-D阵列

Phase initialization for the sinusoidal components of the model.

  • To randomly initialize the phases according to the value of theSeed字段，将此字段设置为"Random"。

  • To specify the same phase, in radians, of all components, set this field to a scalar.

  • To specify the phase, in radians, of each component explicitly, set this field to a 4-D array of sizeN-经过-L-经过-P-经过-NRxAnts。

    • Nis the number of phase initialization values per path.

    • Lis the number of paths.

    • Pis the number of transmit antennas.

    • NRxAntsis the number of receive antennas.

Note

  • When you set theModelType字段到“ gmeds”,Nis equal to 2 ×NTerms。

  • When you set theModelType字段到"Dent",Nis equal toNTerms。
Seed 必需的 标量

随机数发生器种子。要使用随机种子，请将此字段设置为0。

Note

  • To produce distinct results, set this field to a value in the interval

    [ 0 , 2 31 – 1 – K ( K - 1 ) / 2 ] ,

    whereK=P×model。NRxAnts，这是发射和接收天线数量的乘积。避免使用此建议范围之外的值，因为这样做可以导致随机序列，该序列使用建议范围内的值重复结果。

  • The state of MATLAB®随机数生成器，例如通过调用rngfunction, does not affect fading channel random seed behavior.

 要启用此字段，请设置DelayProfile字段到a value other than"Off"and theInitPhase字段到"Random"。
AveragePathGaindB 必需的 Vector

Average gains of the discrete paths in dB

 要启用这些字段，请设置DelayProfile字段到"Custom"。
PathDelays 必需的 Vector

Delays of the discrete paths in seconds. This vector must be the same size asAveragePathGaindB。如果这些延迟不是采样期的倍数，则该函数使用分数延迟过滤器来实现它们。
TxCorrelationMatrix 必需的 Complex-valued matrix

Correlation between each of the transmit antennas, specified as a complex-valued matrix of sizeP-经过-P。

 要启用这些字段，请设置微相关字段到"Custom"。
RxCorrelationMatrix 必需的 Complex-valued matrix

Correlation between each of the receive antennas, specified as a complex-valued matrix of sizeNRxAnts-经过-NRxAnts。

Data Types:struct

Input samples, specified as a complex-valued matrix of sizeT-经过-P, whereTis the number of time-domain samples, andPis the number of transmit antennas. Each column of this input corresponds to the waveform at one transmit antenna.

Data Types:双倍的|single
Complex Number Support:Yes

Output Arguments

collapse all

Channel output waveform, returned as a complex-valued matrix. Each column ofrxcorresponds to the waveform at a receive antenna. This output has the same number of rows as thetxinput.

Data Types:双倍的|single
Complex Number Support:Yes

信道建模的信息,作为struct返回ure containing these fields.

Parameter Field Values 描述
ChannelFilterDelay

标量值

 Implementation delay of the internal channel filtering, in samples
PathGains

Numeric array

Complex gain of the discrete channel paths, returned as a numeric array of sizeT-经过-L-经过-P-经过-NRxAnts。

  • Tis the number of output samples.

  • Lis the number of paths.

  • Pis the number of transmit antennas.

  • NRxAntsis the number of receive antennas.
路径采样

Row vector

Delays of the discrete channel paths, in samples, returned at the sampling rate specified in theSamplingRatefield of themodelinput.
AveragePathGaindB Row vector

Average gains of the discrete paths in dB

Data Types:struct

Algorithms

collapse all

Fading Channel Model Delay

This function implements the MIMO multipath fading channel model specified in[1]and[2]。传输波形通过输入结构指定的多路径雷利褪色通道模型model。The function resamples the delay profile of themodel输入以匹配输入波形采样率。当路径延迟不是采样率的倍数时，该函数使用分数延迟过滤器来实现它们。这些过滤器引入了实施延迟info。ChannelFilterDelaysamples. The waveform passing through the channel passes through these filters and incurs this channel filter delay regardless of the value of the path delays.

参考

[1]3GPP TS 36.101. “Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio transmission and reception.”3rd Generation Partnership Project; Technical Specification Group Radio Access Network。https://www.3gpp.org。

[2] 3GPP TS 36.104. “Evolved Universal Terrestrial Radio Access (E-UTRA); Base Station (BS) radio transmission and reception.”3rd Generation Partnership Project; Technical Specification Group Radio Access Network。https://www.3gpp.org。

[3] Dent, P., G. E. Bottomley, and T. Croft. “Jakes Fading Model Revisited.”电子信。29, no. 13 (1993): 1162–1163.

[4]Pätzold，Matthias，Cheng-Xiang Wang和BjørnOlav Hogstad。“两种新的基于Sinusoids的方法，用于有效地生成多个不相关的雷利褪色波形。”IEEE Transactions on Wireless Communications。8，不。6（2009）：3122–3131。

Version History

Introduced in R2013b

See Also

|||||