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wlanHTConfig

Configure HT transmission

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Description

ThewlanHTConfigobject is a configuration object for the WLAN high throughput (HT) packet format.

Creation

Syntax

cfgHT = wlanHTConfig
cfgHT = wlanHTConfig(Name,Value)

Description

example

cfgHT= wlanHTConfigcreates a configuration object that initializes parameters for an IEEE®802.11™ HTPPDU.

example

cfgHT= wlanHTConfig(Name,Value)设置使用一个或多个属性名称-值对. Enclose each property name in quotation marks. For example,wlanHTConfig('GuardInterval','Short')specifies a 400 nanosecond guard interval (cyclic prefix) duration.

At runtime, the calling function validates object settings for properties relevant to the operation of the function.

Properties

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Channel bandwidth of PPDU transmission, specified as one of these values:

  • 'CBW20'– Channel bandwidth of 20 MHz

  • 'CBW40'– Channel bandwidth of 40 MHz

Data Types:char|string

Number of transmit antennas, specified as a positive integer.

Data Types:double

Cyclic shift values, in nanoseconds, of additional transmit antennas for the pre-HT fields of the waveform. The first four antennas use the cyclic shift values specified in Table 19-9 of[1]. The remainingLantennas use the values you specify in this property, whereL=NumTransmitAntennas– 4. Specify this property as one of these values:

  • An integer in the interval [–200, 0] – thewlanHTConfigobject uses this cyclic shift value for each of theLadditional antennas.

  • A row vector of lengthLof integers in the interval [–200, 0] – thewlanHTConfigobject uses thekth element as the cyclic shift value for the(k+ 4)th transmit antenna.

    Note

    If you specify this property as a row vector of length greater thanL,wlanHTConfigobject uses only the firstLelements. For example, if you set theNumTransmitAntennasproperty to16,wlanHTConfigobject uses only the firstL= 16 – 4 = 12elements of this vector.

Dependencies

To enable this property, set theNumTransmitAntennasproperty to a value greater than4.

Data Types:double

Number of space-time streams in the transmission, specified as1,2,3, or4.

Data Types:double

Number of extension spatial streams in the transmission, specified as0,1,2, or3.

Data Types:double

Spatial mapping scheme, specified as'Direct','Hadamard','Fourier', or'Custom'.

Dependencies

The default value,'Direct', applies only when you set theNumTransmitAntennasandNumSpaceTimeStreamsproperties to the same value. This property must be set to'Custom'when theNumExtensionStreamsproperty is greater than zero.

Spatial mapping matrix, specified as one of these values:

  • A complex-valued scalar. This value applies to all the subcarriers.

  • A complex-valued matrix of size (NSTS+NESS) -by-NT, where:

    • NSTSis the number of space-time streams;

    • NESSis the number of extension spatial streams;

    • NTis the number of transmit antennas.

    In this case, the spatial mapping matrix applies to all the subcarriers.

  • A complex-valued 3-D array of sizeNST-by-(NSTS+NESS)-by-NT, whereNSTis the number of occupied subcarriers. The value ofNSTis the sum of the occupied data and pilot subcarriers. TheChannelBandwidthproperty determines the value ofNST. In this case, each occupied subcarrier has its own spatial mapping matrix.

    This table shows theChannelBandwidthsetting and the correspondingNST:

    ChannelBandwidth Number of Occupied Subcarriers,NST Number of Data Subcarriers Number of Pilot Subcarriers
    'CBW20' 56 52 4
    'CBW40' 114 108 6

Use this property to rotate and scale the output vector of the constellation mapper. The spatial mapping matrix is used for beamforming and mixing space-time streams over the transmit antennas. For more information, see Section 19.3.11.11.2 of[1]. The calling function normalizes the spatial mapping matrix for each subcarrier.

Example:[0.5 0.3; 0.4 0.4; 0.5 0.8]represents a spatial mapping matrix with three space-time streams and two transmit antennas.

Dependencies

This property applies only when you set theSpatialMappingproperty to'Custom'.

Data Types:double
Complex Number Support:Yes

Modulation and coding scheme (MCS) used for transmission, specified as an integer in the interval [0, 31]. Each value of this property corresponds to a modulation type and coding rate in accordance with this table.

MCS Modulation Coding Rate

0,8,16, or24

 Binary phase-shift keying (BPSK) 1/2

1,9,17, or25

 Quadrature phase-shift keying (QPSK) 1/2

2,10,18, or26

 QPSK 3/4

3,11,19, or27

 16-point quadrature amplitude modulation (16-QAM) 3/4

4,12,20, or28

 16-QAM 3/4

5,13,21, or29

 64-QAM 2/3

6,14,22, or30

 64-QAM 3/4

7,15,23, or31

 64-QAM 5/6

这个属性的值区间[0、7]specify one spatial stream. Values in the interval [8, 15] specify two spatial streams. Values in the interval [16, 23] specify three spatial streams. Values in the interval [24, 31] specify four spatial streams.

For more information on MCS-dependent transmission parameters, see Section 19.5 of[1]. If the number of space-time streams is equal to the number of spatial streams, no space-time block coding (STBC) is applied to the HT-Data field. For a description of STBC, see Section 19.3.11.9.2 of[1].

Example:A value of22specifies an MCS with three spatial streams, 64-QAM, and a coding rate of ¾.

Data Types:double

Guard interval (cyclic prefix) duration for the data field within a packet, specified as one of these values:

  • 'Long'– Guard interval duration of 800 ns

  • 'Short'– Guard interval duration of 400 ns

Data Types:char|string

Forward-error-correction (FEC) coding type for the HT-Data field, specified as'BCC'for binary convolutional coding (BCC) or'LDPC'for low-density parity-check (LDPC) coding.

Data Types:char|string

Physical layer convergence procedure (PLCP) service data unit (PSDU) length, in bytes, specified as an integer in the interval [0, 216– 1]. To indicate a sounding packet for which there are no data bits to recover, set this property to0.

Data Types:double

MAC protocol data unit (MPDU) aggregation indicator, specified as a numeric or logical1(true) or0(false). To specify that the generated packet uses MPDU aggregation, set this property to1(true).

Dependencies

This property does not apply when you set theMCSproperty to0

Data Types:logical

Recommend smoothing for channel estimation, specified as a numeric or logical1(true) or0(false).

  • If the frequency profile does not vary across the channel, the receiver sets this property to1(true). In this case, frequency-domain smoothing is recommended as part of channel estimation.

  • If the frequency profile varies across the channel, the receiver sets this property to0(false). In this case, frequency-domain smoothing is not recommended as part of channel estimation.

Data Types:logical

Examples

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Open Live Script

创建一个HT配置object. After creating the object update the number of transmit antennas and space-time streams.

cfgHT = wlanHTConfig
cfgHT = wlanHTConfig with properties: ChannelBandwidth: 'CBW20' NumTransmitAntennas: 1 NumSpaceTimeStreams: 1 SpatialMapping: 'Direct' MCS: 0 GuardInterval: 'Long' ChannelCoding: 'BCC' PSDULength: 1024 AggregatedMPDU: 0 RecommendSmoothing: 1

Update the number of antennas to two, and number of space-time streams to four.

cfgHT.NumTransmitAntennas = 2; cfgHT.NumSpaceTimeStreams = 4
cfgHT = wlanHTConfig with properties: ChannelBandwidth: 'CBW20' NumTransmitAntennas: 2 NumSpaceTimeStreams: 4 SpatialMapping: 'Direct' MCS: 0 GuardInterval: 'Long' ChannelCoding: 'BCC' PSDULength: 1024 AggregatedMPDU: 0 RecommendSmoothing: 1
Open Live Script

Create awlanHTConfigobject with a PSDU length of 2048 bytes, and using BCC forward error correction.

cfgHT = wlanHTConfig('PSDULength',2048); cfgHT.ChannelBandwidth ='CBW20'
cfgHT = wlanHTConfig with properties: ChannelBandwidth: 'CBW20' NumTransmitAntennas: 1 NumSpaceTimeStreams: 1 SpatialMapping: 'Direct' MCS: 0 GuardInterval: 'Long' ChannelCoding: 'BCC' PSDULength: 2048 AggregatedMPDU: 0 RecommendSmoothing: 1

More About

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References

[1] IEEE Std 802.11-2016 (Revision of IEEE Std 802.11-2012). “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.” IEEE Standard for Information technology — Telecommunications and information exchange between systems. Local and metropolitan area networks — Specific requirements.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

See Also

Objects

Functions

Apps

Topics

Introduced in R2015b

WLAN Toolbox Documentation

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