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wlanVHTConfig Properties

Define parameter values for VHT format packet

The wlanVHTConfig object specifies the transmission properties for the IEEE® 802.11 very high throughput (VHT) format physical layer (PHY) packet.

After you create an object, use dot notation to change or access the object parameters. For example:

Create a wlanVHTConfig object. Then modify the default setting for the ChannelBandwidth property.

cfgVHT = wlanVHTConfig;
cfgVHT.ChannelBandwidth = 'CBW20';

VHT Format Configuration

expand all

Channel bandwidth, specified as 'CBW20', 'CBW40', 'CBW80', or 'CBW160'. If the transmission has multiple users, the same channel bandwidth is applied to all users. The default value of 'CBW80' sets the channel bandwidth to 80 MHz.

Data Types: char | string

Number of users, specified as 1, 2, 3, or 4. (NUsers)

Data Types: double

Position of users, specified as an integer row vector with length equal to NumUsers and element values from 0 to 3 in a strictly increasing order. This property applies when NumUsers > 1.

Example: [0 2 3] indicates positions for three users, where the first user occupies position 0, the second user occupies position 2, and the third user occupies position 3.

Data Types: double

Number of transmit antennas, specified as a scalar integer from 1 to 8.

Data Types: double

Number of space-time streams in the transmission, specified as a scalar or vector.

  • For a single user, the number of space-time streams is a scalar integer from 1 to 8.

  • For multiple users, the number of space-time streams is a 1-by-NUsers vector of integers from 1 to 4, where the vector length, NUsers, is an integer from 1 to 4.

Example: [1 3 2] is the number of space-time streams for each user.

Note

The sum of the space-time stream vector elements must not exceed eight.

Data Types: double

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

Data Types: char | string

Spatial mapping matrix, specified as a scalar, matrix, or 3-D array. Use this property to apply a beamforming steering matrix, and to rotate and scale the constellation mapper output vector. If applicable, scale the space-time block coder output instead. SpatialMappingMatrix applies when the SpatialMapping property is set to 'Custom'. For more information, see IEEE Std 802.11™-2012, Section 20.3.11.11.2.

  • When specified as a scalar, a constant value applies to all the subcarriers.

  • When specified as a matrix, the size must be NSTS_Total-by-NT. The spatial mapping matrix applies to all the subcarriers. NSTS_Total is the sum of space-time streams for all users, and NT is the number of transmit antennas.

  • When specified as a 3-D array, the size must be NST-by-NSTS_Total-by-NT. NST is the sum of the occupied data (NSD) and pilot (NSP) subcarriers, as determined by ChannelBandwidth. NSTS_Total is the sum of space-time streams for all users. NT is the number of transmit antennas.

    NST increases with channel bandwidth.

    ChannelBandwidthNumber of Occupied Subcarriers (NST)Number of Data Subcarriers (NSD)Number of Pilot Subcarriers (NSP)
    'CBW20'56524
    'CBW40'1141086
    'CBW80'2422348
    'CBW160'48446816

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 two space-time streams and three transmit antennas.

Data Types: double
Complex Number Support: Yes

Enable signaling of a transmission with beamforming, specified as a logical. Beamforming is performed when setting is true. This property applies when NumUsers equals 1 and SpatialMapping is set to 'Custom'. The SpatialMappingMatrix property specifies the beamforming steering matrix.

Data Types: logical

Enable space-time block coding (STBC) of the PPDU data field, specified as a logical. STBC transmits multiple copies of the data stream across assigned antennas.

  • When set to false, no STBC is applied to the data field, and the number of space-time streams is equal to the number of spatial streams.

  • When set to true, STBC is applied to the data field, and the number of space-time streams is double the number of spatial streams.

See IEEE 802.11ac™-2013, Section 22.3.10.9.4 for further description.

Note

STBC is relevant for single-user transmissions only.

Data Types: logical

Modulation and coding scheme used in transmitting the current packet, specified as a scalar or vector.

  • For a single user, the MCS value is a scalar integer from 0 to 9.

  • For multiple users, MCS is a 1-by-NUsers vector of integers or a scalar with values from 0 to 9, where the vector length, NUsers, is an integer from 1 to 4.

MCSModulationCoding Rate
0BPSK1/2
1QPSK1/2
2QPSK3/4
316QAM1/2
416QAM3/4
564QAM2/3
664QAM3/4
764QAM5/6
8256QAM3/4
9256QAM5/6

Data Types: double

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. Providing a character vector or a single cell character vector defines the channel coding type for a single user or all users in a multiuser transmission. By providing a cell array different channel coding types can be specified per user for a multiuser transmission.

Data Types: char | cell | string

Number of bytes in the A-MPDU pre-EOF padding, specified as a scalar integer or vector of integers.

  • For a single user, APEPLength is a scalar integer from 0 to 1,048,575.

  • For multi-user, APEPLength is a 1-by-NUsers vector of integers or a scalar with values from 0 to 1,048,575, where the vector length, NUsers, is an integer from 1 to 4.

  • APEPLength = 0 for a null data packet (NDP).

APEPLength is used internally to determine the number of OFDM symbols in the data field. For more information, see IEEE Std 802.11ac-2013, Table 22-1.

Data Types: double

This property is read-only.

Number of bytes carried in the user payload, including the A-MPDU and any MAC padding. For a null data packet (NDP) the PSDU length is zero.

  • For a single user, the PSDU length is a scalar integer from 1 to 1,048,575.

  • For multiple users, the PSDU length is a 1-by-NUsers vector of integers from 1 to 1,048,575, where the vector length, NUsers, is an integer from 1 to 4.

  • When undefined, PSDULength is returned as an empty, []. This can happen when the set of property values for the object are in an invalid state.

PSDULength is a read-only property and is calculated internally based on the APEPLength property and other coding-related properties, as specified in IEEE Std 802.11ac-2013, Section 22.4.3. It is accessible by direct property call.

Example: [1035 4150] is the PSDU length vector for a wlanVHTConfig object with two users, where the MCS for the first user is 0 and the MCS for the second user is 3.

Data Types: double

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

Group identification number, specified as a scalar integer from 0 to 63.

  • A group identification number of either 0 or 63 indicates a VHT single-user PPDU.

  • A group identification number from 1 to 62 indicates a VHT multi-user PPDU.

Data Types: double

Abbreviated indication of the PSDU recipient, specified as a scalar integer from 0 to 511.

  • For an uplink transmission, the partial identification number is the last nine bits of the basic service set identifier (BSSID).

  • For a downlink transmission, the partial identification of a client is an identifier that combines the association ID with the BSSID of its serving AP.

For more information, see IEEE Std 802.11ac-2013, Table 22-1.

Data Types: double

References

[1] IEEE Std 802.11ac™-2013 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 — Amendment 4: Enhancements for Very High Throughput for Operation in Bands below 6 GHz.

[2] 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.

Introduced in R2015b

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