wlanMPDUDecode

Decode MPDU

Syntax

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu)

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu,phyFormat)

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu,cfgPHY)

[cfgMAC,payload,status] = wlanMPDUDecode(___,Name=Value)

Description

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu) validates the frame check sequence (FCS) and decodes the specified MAC protocol data unit (MPDU), mpdu. The function returns cfgMAC, a wlanMACFrameConfig configuration object, payload, one or more MAC service data units (MSDUs), and status, the result of the MPDU decoding.

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu,phyFormat) validates the FCS and decodes the specified MPDU by using the parameters appropriate for the specified PHY format, phyFormat.

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu,cfgPHY) validates the FCS and decodes the specified MPDU by using PHY transmission parameters, cfgPHY.

[cfgMAC,payload,status] = wlanMPDUDecode(___,Name=Value) specifies options using one or more name-value arguments in addition any input argument combination from previous syntaxes.

Examples

Decode MPDU

Create a wlanMACFrameConfig object with default properties.

cfgMAC = wlanMACFrameConfig;

Generate a random payload.

payload = randi([0 255],1,40);

Use the payload and MAC frame configuration to generate a MAC frame.

mpdu = wlanMACFrame(payload,cfgMAC,OutputFormat="bits");

Decode the MAC frame and display the status of the decoding.

[rxCfgMAC,payload,status] = wlanMPDUDecode(mpdu);
disp(status)

    Success

Decode HE SU MPDU

Create a WLAN MAC frame configuration object for a QoS Data MAC frame, specifying the high-efficiency single-user (HE SU) format. Enable MPDU aggregation and disable MSDU aggregation.

frameType = "QoS Data";
phyFormat = "HE-SU";
cfgMAC =  wlanMACFrameConfig(FrameType=frameType,FrameFormat=phyFormat, ...
    MPDUAggregation=true,MSDUAggregation=false);

Create a cell array of MSDUs, specifying each MSDU as a numeric vector of octets in bit format.

msduList = repmat({randi([0 255],32,1)},1,4);

Generate the MPDU for an HE SU PHY configuration.

cfgPHY = wlanHESUConfig(MCS=5);
[ampdu,ampduLength] = wlanMACFrame(msduList,cfgMAC,cfgPHY,OutputFormat="bits");

Deaggregate the A-MPDU.

[mpduList,delimiterCRCFailure,status] = wlanAMPDUDeaggregate(ampdu,cfgPHY);

Decode the first MPDU and display the success of the decoding.

[cfg,msdu,decodeStatus] = wlanMPDUDecode(mpduList{1},phyFormat,DataFormat="octets");
disp(decodeStatus)

    Success

Decode Non-HT MPDU

Create a WLAN MAC frame configuration object for a QoS Data frame, and then generate the MPDU.

cfgMAC = wlanMACFrameConfig(FrameType="QoS Data");
payload = randi([0 255],1,40);
mpdu = wlanMACFrame(payload,cfgMAC,OutputFormat="bits");

Create a non-high-throughput-format (non-HT-format) configuration object with default settings.

cfgPHY = wlanNonHTConfig;

Return the MSDUs by decoding the MPDU for the specified PHY format configuration.

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu,cfgPHY);

Confirm successful decoding by displaying the status.

disp(status)

    Success

Decode MPDUs Extracted from A-MPDU

Create a WLAN MAC frame configuration object for a VHT A-MPDU.

txCfgMAC = wlanMACFrameConfig(FrameType="QoS Data", ...
    FrameFormat="VHT");

Create a VHT-format configuration object with default settings.

cfgPHY = wlanVHTConfig;

Generate a random payload of eight MSDUs.

txPayload =  repmat({randi([0 255],1,40)},1,8);

Generate the A-MPDU containing eight MPDUs for the specified MAC and PHY configurations.

ampdu = wlanMACFrame(txPayload,txCfgMAC,cfgPHY);

Extract the list of MPDUs by deaggregating the A-MPDU. Display the status of the deaggregation and the delimiter CRC.

[mpduList,failCRC,status] = wlanAMPDUDeaggregate(ampdu,cfgPHY, ...
    DataFormat="octets");
disp(status)

    Success

disp(failCRC)

   0   0   0   0   0   0   0   0

Decode all of the MPDUs in the extracted. Confirm successful decoding by displaying the status.

if strcmp(status,"Success")
    for i = 1:numel(mpduList)
        if ~failCRC(i)
            [cfgMAC,payload,status(i)] = ...
                wlanMPDUDecode(mpduList{i},cfgPHY, ...
                DataFormat="octets");
        end
    end
end
disp(status)

    Success    Success    Success    Success    Success    Success    Success    Success

Input Arguments

mpdu — MPDU to be decoded

binary-valued vector | vector of integers in the interval [0, 255] | string scalar | character array

MPDU to be decoded, specified as one of these values.

• A binary-valued vector representing the MPDU in bit form

• A vector of integers in the interval [0, 255] representing octets in decimal format

• A string scalar representing the MPDU as octets in hexadecimal format

• A character vector representing the MPDU as octets in hexadecimal format

• A character array, where each row represents an octet in hexadecimal format

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | char | string

phyFormat — PHY format

'EHT-SU' | 'HE-SU' | 'HE-EXT-SU' | 'HE-MU | 'HE-TB' | 'VHT' | 'HT' | 'Non-HT'

PHY format, specified as one of these values.

• 'EHT-SU' — Extremely high-throughput SU (EHT SU) format

• 'HE-SU' — High-efficiency single-user (HE SU) format

• 'HE-EXT-SU' — HE extended-range SU (HE ER SU) format

• 'HE-MU' — HE multi-user (HE MU) format

• 'HE-TB' — HE trigger-based (HE TB) format

• 'VHT' — Very-high-throughput (VHT) format

• 'HT' — High-throughput (HT) format

• 'Non-HT' — Non-HT format

Data Types: char | string

cfgPHY — PHY format and transmission parameters

wlanEHTMUConfig | wlanHESUConfig object | wlanHEMUConfig object | wlanHETBConfig object | wlanHERecoveryConfig object | wlanVHTConfig object | wlanHTConfig object | wlanNonHTConfig object

PHY format and transmission parameters, specified as one of these objects.

• wlanEHTMUConfig— EHT SU format

• wlanHESUConfig — HE SU or HE ER SU format

• wlanHEMUConfig — HE MU format

• wlanHETBConfig — HE TB format

• wlanHERecoveryConfig — Recovered HE transmission in HE SU, HE ER SU, or HE MU format

• wlanVHTConfig — VHT format

• wlanHTConfig — HT format

• wlanNonHTConfig — Non-high-throughput (non-HT) format

If you specify this input as an object of type wlanEHTMUConfig, this object must specify the configuration for a single user transmission.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: DataFormat='octets'

DataFormat — Format of input MPDU

'bits' (default) | 'octets'

Format of input MPDU, specified as one of these values.

• 'bits' — Specify the mpdu input in bit format

• 'octets' — Specify the mpdu input in octet format

Data Types: char | string

SuppressWarnings — Suppress warning messages

false or 0 (default) | true or 1

Suppress warning messages, specified as one of these values.

• false or 0 — Allow warning messages.

• true or 1 — Suppress warning messages.

Data Types: logical

IsMeshFrame — Mesh frame indication

false or 0 (default) | true or 1

Mesh frame indication, specified as a numeric or logical 1 (true) or 0 ( false). To indicate that the frame originates from a mesh station in a mesh BSS, set this property to 1 (true). The function uses this argument only when decoding a frame of type QoS Data or QoS Null.

Data Types: logical

Output Arguments

cfgMAC — MAC frame configuration

wlanMACFrameConfig object

MAC frame configuration, returned as a wlanMACFrameConfig object.

payload — One or more MSDUs

cell array of character vectors

One or more MSDUs, returned as a cell array of character arrays. The function returns a character array for each MSDU. In these character arrays, each row is the hexadecimal representation of an octet. For each MAC frame that contains no data, the function returns payload as an empty cell array.

Data Types: cell

status — Status of MPDU decoding

integer in the interval [–31, 0]

Status of MPDU decoding, returned as an integer in the interval [–31, 0]. Each value of status corresponds to a member of the wlanMACDecodeStatus enumeration class, which indicates the status of MAC frame decoding according to this table.

Enumeration Value	Member of Enumeration Class	Decoding Status
0	Success	MAC frame successfully decoded
-1	FCSFailed	Frame check sequence (FCS) failed
-2	InvalidProtocolVersion	Invalid protocol version
-3	UnsupportedFrameType	Unsupported frame type
-4	UnsupportedFrameSubtype	Unsupported frame subtype
-5	NotEnoughData	Insufficient data to decode frame
-6	UnsupportedBAVariant	Unsupported variant of Block Ack frame
-7	UnknownBitmapSize	Unknown bitmap size
-8	UnknownAddressExtMode	Unknown address extension mode
-9	MalformedAMSDULength	Malformed aggregate MAC service data unit (A-MSDU) with invalid length
-10	MalformedSSID	Malformed service set identifier (SSID) information element (IE)
-11	MalformedSupportedRatesIE	Malformed supported rates IE
-12	MalformedIELength	Malformed IE length field
-13	MissingMandatoryIEs	Mandatory IEs missing
-14	NoMPDUFound	No MPDU found in A-MPDU
-15	CorruptedAMPDU	All the delimiters in received A-MPDU failed cyclic redundancy check (CRC)
-16	InvalidDelimiterLength	Invalid length field in MPDU delimiter
-17	MaxAMSDULenthExceeded	A-MSDU exceeds maximum length limit
-18	MaxMPDULengthExceeded	MPDU exceeds maximum length limit
-19	MaxMMPDULengthExceeded	MAC management frame exceeds maximum length limit
-20	MaxMSDULengthExceeded	MSDU exceeds maximum length limit
-21	UnexpectedProtectedFrame	Invalid value of protected bit for this frame type
-22	UnsupportedTriggerType	Unsupported trigger frame type
-23	UnknownHELTFTypeAndGI	Unknown guard interval (GI) and high-efficiency long training field (HE-LTF) type
-24	UnknownAPTxPower	Unknown value for AP Tx Power subfield of Common Info field
-25	UnknownAID12Value	Unknown value for AID12 subfield of User Info field
-26	UnknownRUAllocation	Unknown value for B7-B1 in RU Allocation subfield of User Info field
-27	UnknownULMCS	Unknown value for UL MCS subfield of User Info field
-28	UnknownTargetRSSI	Unknown value for UL Target RSSI subfield of User Info field
-29	UnsupportedBARType	Unsupported value for BAR Type subfield of BAR Control field
-30	MissingUserInfo	Received trigger frame contains invalid User Info field
-31	InvalidLSIGLength	Invalid value for UL Length subfield of Common Info field, corresponding to length of legacy signal (L-SIG) field.

An enumeration value other than 0 means that MPDU decoding failed. If the decoding fails, the cfgMAC output displays no properties, and the function returns the payload output as an empty cell array.

Data Types: int16

Extended Capabilities

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

Version History

Introduced in R2019a