wlanHTConfig
Configure HT transmission
Description
The wlanHTConfig
object is a configuration object for the WLAN
high throughput (HT) packet format.
Creation
Description
creates a configuration
object that initializes parameters for an IEEE®
802.11™ HT PPDU.cfgHT
= wlanHTConfig
sets properties using one or more name-value pairs. Enclose each property name in
quotation marks. For example, cfgHT
= wlanHTConfig(Name,Value
)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
ChannelBandwidth
— Channel bandwidth of PPDU transmission
'CBW20'
(default) | 'CBW40'
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
NumTransmitAntennas
— Number of transmit antennas
1
(default) | positive integer
Number of transmit antennas, specified as a positive integer.
Data Types: double
PreHTCyclicShifts
— Cyclic shift values of additional transmit antennas
-75
(default) | integer in the interval [–200, 0] | row vector
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 remaining
L antennas use the values you specify in this property, where L = NumTransmitAntennas
–
4. Specify this property as one of these values:
An integer in the interval [–200, 0] – the
wlanHTConfig
object uses this cyclic shift value for each of the L additional antennas.A row vector of length L of integers in the interval [–200, 0] – the
wlanHTConfig
object uses the kth 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 than L, the
wlanHTConfig
object uses only the first L elements. For example, if you set theNumTransmitAntennas
property to16
, thewlanHTConfig
object uses only the first L= 16 – 4 = 12 elements of this vector.
Dependencies
To enable this property, set the NumTransmitAntennas
property to a value greater than
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
.
Data Types: double
SpatialMapping
— Spatial mapping scheme
'Direct'
(default) | 'Hadamard'
| 'Fourier'
| 'Custom'
Spatial mapping scheme, specified as 'Direct'
,
'Hadamard'
, 'Fourier'
, or
'Custom'
.
Dependencies
The default value, 'Direct'
, applies only when you set the
NumTransmitAntennas
and NumSpaceTimeStreams
properties to the same value. This property must be
set to 'Custom'
when the NumExtensionStreams
property is greater than zero.
SpatialMappingMatrix
— Spatial mapping matrix
1
(default) | complex-valued scalar | complex-valued matrix | complex-valued 3-D array
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:
NSTS is the number of space-time streams;
NESS is the number of extension spatial streams;
NT is the number of transmit antennas.
In this case, the spatial mapping matrix applies to all the subcarriers.
A complex-valued 3-D array of size NST-by-(NSTS + NESS)-by-NT, where NST is the number of occupied subcarriers. The value of NST is the sum of the occupied data and pilot subcarriers. The
ChannelBandwidth
property determines the value of NST. In this case, each occupied subcarrier has its own spatial mapping matrix.This table shows the
ChannelBandwidth
setting and the corresponding NST: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 the SpatialMapping
property to 'Custom'
.
Data Types: double
Complex Number Support: Yes
MCS
— MCS used for transmission
0
(default) | integer in the interval [0, 31]
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 |
---|---|---|
| Binary phase-shift keying (BPSK) | 1/2 |
| Quadrature phase-shift keying (QPSK) | 1/2 |
| QPSK | 3/4 |
| 16-point quadrature amplitude modulation (16-QAM) | 3/4 |
| 16-QAM | 3/4 |
| 64-QAM | 2/3 |
| 64-QAM | 3/4 |
| 64-QAM | 5/6 |
Values of this property in the interval [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 of 22
specifies an MCS with three spatial
streams, 64-QAM, and a coding rate of ¾.
Data Types: double
GuardInterval
— Guard interval (cyclic prefix) duration
'Long'
(default) | 'Short'
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
ChannelCoding
— FEC coding type
'BCC'
(default) | 'LDPC'
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
PSDULength
— PSDU length
1024
(default) | integer in the interval [0, 216 – 1]
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 to 0
.
Data Types: double
AggregatedMPDU
— MPDU aggregation indicator
false
or 0
(default) | true
or 1
MAC protocol data unit (MPDU) aggregation indicator, specified as a numeric or
logical 1
(true
) or 0
(false
). To specify that the generated packet uses MPDU
aggregation, set this property to 1
(true
).
Dependencies
This property does not apply when you set the MCS
property to 0
Data Types: logical
RecommendSmoothing
— Recommend smoothing for channel estimation
true
or 1
(default) | false
or 0
Recommend smoothing for channel estimation, specified as a numeric or logical
1
(true
) or 0
(false
).
If the frequency profile does not vary across the channel, the receiver sets this property to
1
(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
0
(false
). In this case, frequency-domain smoothing is not recommended as part of channel estimation.
Data Types: logical
Object Functions
transmitTime | Packet transmission time |
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
More About
PPDU
The physical layer (PHY) protocol data unit (PPDU) is the complete physical layer convergence procedure (PLCP) frame, including PLCP headers, MAC headers, the MAC data field, and the MAC and PLCP trailers.
References
[1] IEEE Std 802.11-2020 (Revision of IEEE Std 802.11-2016). “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™.
Version History
Introduced in R2015b
See Also
Functions
wlanHTData
|wlanHTDataRecover
|wlanHTLTF
|wlanHTLTFDemodulate
|wlanHTOFDMInfo
|wlanHTSIG
|wlanHTSIGRecover
|wlanHTSTF
|wlanWaveformGenerator
Apps
Comando de MATLAB
Ha hecho clic en un enlace que corresponde a este comando de MATLAB:
Ejecute el comando introduciéndolo en la ventana de comandos de MATLAB. Los navegadores web no admiten comandos de MATLAB.
Select a Web Site
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
You can also select a web site from the following list:
How to Get Best Site Performance
Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.
Americas
- América Latina (Español)
- Canada (English)
- United States (English)
Europe
- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)
- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom (English)