wlanHTConfig

Create HT format configuration object

Syntax

cfgHT = wlanHTConfig

cfgHT = wlanHTConfig(Name,Value)

Description

cfgHT = wlanHTConfig creates a configuration object that initializes parameters for an IEEE^® 802.11™ high throughput mixed (HT-mixed) format PPDU.

cfgHT = wlanHTConfig(Name,Value) creates an HT format configuration object that overrides the default settings using one or more Name,Value pair arguments.

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

Examples

Create HT Configuration Object with Default Settings

Create an HT configuration 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

Create wlanHTConfig Object

Create a wlanHTConfig object 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

Input Arguments

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'ChannelBandwidth','CBW40','NumTransmitAntennas',2

'ChannelBandwidth' — Channel bandwidth

'CBW20' (default) | 'CBW40'

Channel bandwidth in MHz, specified as 'CBW20' or 'CBW40'.

Data Types: char | string

'NumTransmitAntennas' — Number of transmit antennas

1 (default) | 2 | 3 | 4

Number of transmit antennas, specified as 1, 2, 3, or 4.

Data Types: double

'NumSpaceTimeStreams' — Number of space-time streams

1 (default) | 2 | 3 | 4

Number of space-time streams in the transmission, specified as 1, 2, 3, or 4.

Data Types: double

'NumExtensionStreams' — Number of extension spatial streams

0 (default) | 1 | 2 | 3

Number of extension spatial streams in the transmission, specified as 0, 1, 2, or 3. When NumExtensionStreams is greater than 0, SpatialMapping must be 'Custom'.

Data Types: double

'SpatialMapping' — Spatial mapping scheme

'Direct' (default) | 'Hadamard' | 'Fourier' | 'Custom'

Spatial mapping scheme, specified as 'Direct', 'Hadamard', 'Fourier', or 'Custom'. The default value 'Direct' applies when NumTransmitAntennas and NumSpaceTimeStreams are equal.

Data Types: char | string

'SpatialMappingMatrix' — Spatial mapping matrix

1 (default) | scalar | matrix | 3-D array

Spatial mapping matrix, specified as a scalar, matrix, or 3-D array. Use this property to rotate and scale the constellation mapper output vector. This property applies when the SpatialMapping property is set to 'Custom'. The spatial mapping matrix is used for beamforming and mixing space-time streams over the transmit antennas.

• When specified as a scalar, NumTransmitAntennas = NumSpaceTimeStreams = 1 and a constant value applies to all the subcarriers.

• When specified as a matrix, the size must be (N_STS + N_ESS)-by-N_T. N_STS is the number of space-time streams. N_ESS is the number of extension spatial streams. N_T is the number of transmit antennas. The spatial mapping matrix applies to all the subcarriers. The first N_STS and last N_ESS rows apply to the space-time streams and extension spatial streams respectively.

• When specified as a 3-D array, the size must be N_ST-by-(N_STS + N_ESS)-by-N_T. N_ST is the sum of the data and pilot subcarriers, as determined by ChannelBandwidth. N_STS is the number of space-time streams. N_ESS is the number of extension spatial streams. N_T is the number of transmit antennas. In this case, each data and pilot subcarrier can have its own spatial mapping matrix.

  The table shows the ChannelBandwidth setting and the corresponding N_ST.

  ChannelBandwidth	NST
  'CBW20'	56
  'CBW40'	114

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 having three space-time streams and two transmit antennas.

Data Types: double
Complex Number Support: Yes

'MCS' — Modulation and coding scheme

0 (default) | integer from 0 to 31

Modulation and coding scheme to use for transmitting the current packet, specified as an integer from 0 to 31. The MCS setting identifies which modulation and coding rate combination is used, and the number of spatial streams (N_SS).

MCS(Note 1)	NSS(Note 1)	Modulation	Coding Rate
0, 8, 16, or 24	1, 2, 3, or 4	BPSK	1/2
1, 9, 17, or 25	1, 2, 3, or 4	QPSK	1/2
2, 10, 18, or 26	1, 2, 3, or 4	QPSK	3/4
3, 11, 19, or 27	1, 2, 3, or 4	16QAM	1/2
4, 12, 20, or 28	1, 2, 3, or 4	16QAM	3/4
5, 13, 21, or 29	1, 2, 3, or 4	64QAM	2/3
6, 14, 22, or 30	1, 2, 3, or 4	64QAM	3/4
7, 15, 23, or 31	1, 2, 3, or 4	64QAM	5/6
Note-1 MCS from 0 to 7 have one spatial stream. MCS from 8 to 15 have two spatial streams. MCS from 16 to 23 have three spatial streams. MCS from 24 to 31 have four spatial streams.

See IEEE 802.11-2012, Section 20.6 for further description of MCS dependent parameters.

When working with the HT-Data field, if the number of space-time streams is equal to the number of spatial streams, no space-time block coding (STBC) is used. See IEEE 802.11-2012, Section 20.3.11.9.2 for further description of STBC mapping.

Example: 22 indicates an MCS with three spatial streams, 64-QAM modulation, and a 3/4 coding rate.

Data Types: double

'GuardInterval' — Cyclic prefix length for the data field within a packet

'Long' (default) | 'Short'

Cyclic prefix length for the data field within a packet, specified as 'Long' or 'Short'.

• The long guard interval length is 800 ns.

• The short guard interval length is 400 ns.

Data Types: char | string

'ChannelCoding' — Type of forward error correction coding

'BCC' (default) | 'LDPC'

Type of forward error correction coding for the data field, specified as 'BCC' (default) or 'LDPC'. 'BCC' indicates binary convolutional coding, and 'LDPC' indicates low density parity check coding.

Data Types: char | cell | string

'PSDULength' — Number of bytes carried in the user payload

1024 (default) | integer from 0 to 65,535

Number of bytes carried in the user payload, specified as an integer from 0 to 65,535. A PSDULength of 0 implies a sounding packet for which there are no data bits to recover.

Example: 512

Data Types: double

'AggregatedMPDU' — MPDU aggregation indicator

false (default) | true

MPDU aggregation indicator, specified as a logical. Setting AggregatedMPDU to true indicates that the current packet uses A-MPDU aggregation.

Dependencies

This property is not applicable when MCS is 0.

Data Types: logical

'RecommendSmoothing' — Recommend smoothing for channel estimation

true (default) | false

Recommend smoothing for channel estimation, specified as a logical.

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

Data Types: logical

Output Arguments

cfgHT — HT PPDU configuration

wlanHTConfig object

HT PPDU configuration, returned as a wlanHTConfig object. The properties of cfgHT are described in wlanHTConfig Properties.

More About

PPDU

The physical layer convergence procedure (PLCP) protocol data unit (PPDU) is the complete PLCP frame, including PLCP headers, MAC headers, the MAC data field, and the MAC and PLCP trailers.

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.

Extended Capabilities

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