wlanMPDUDecode

Decode MPDU

Syntax

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

[cfgMAC,payload,status] = wlanMPDUDecode(___,'DataFormat',format)

Description

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu,cfgPHY) recovers payload, one or more MAC service data units (MSDUs), by decoding MAC protocol data unit (MPDU) mpdu for physical layer (PHY) format configuration object cfgPHY. The function also returns status, which indicates the result of MPDU decoding, and cfgMAC, a wlanMACFrameConfig configuration object.

[cfgMAC,payload,status] = wlanMPDUDecode(___,'DataFormat',format) specifies the data format of the input MPDU to be decoded.

Examples

Decode MPDU in Bit Form

Create a WLAN MAC frame configuration object for a QoS data frame, and then generate the QoS data MPDU in octet form.

txCfgMAC = wlanMACFrameConfig('FrameType','QoS Data');
mpduOctets = wlanMACFrame(randi([0 255],1,40),txCfgMAC);

Convert the MPDU to bit form.

mpdu = reshape(de2bi(hex2dec(mpduOctets), 8)',[],1);

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.

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

Decode MPDU in Octet Form.

Create a WLAN MAC frame configuration object for a QoS data frame, then generate the QoS data MPDU in octet form.

txCfgMAC =  wlanMACFrameConfig('FrameType','QoS Data');
mpdu = wlanMACFrame(randi([0 255],1,40),txCfgMAC);

Create a non-HT-format configuration object with default settings.

cfgPHY = wlanNonHTConfig;

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

[rxCfgMAC,payload,status] = wlanMPDUDecode(mpdu,cfgPHY,'DataFormat','octets');

Decode MPDUs Extracted from A-MPDU

Deaggregate a VHT-format A-MPDU and decode the extracted MPDUs.

Create a WLAN MAC frame configuration object for a VHT-format 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);

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

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

    Success

disp(delimiterCRCFail)

   0   0   0   0   0   0   0   0

Decode all the MPDUs in the extracted list.

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

Input Arguments

mpdu — MPDU to be decoded

binary vector | numeric vector | string scalar | character array

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

• a binary vector representing the MPDU in bit form;

• a numeric vector representing octets in decimal format, where each element is an integer in the interval [0, 255];

• 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: double | char | string

cfgPHY — PHY format configuration

wlanHESUConfig object | wlanVHTConfig object | wlanHTConfig object | wlanNonHTConfig object

PHY format configuration, specified as an object of type wlanHESUConfig, wlanVHTConfig, wlanHTConfig, wlanNonHTConfig. This object defines the PHY format configuration and its applicable properties.

format — Format of the input MPDU

'bits' (default) | 'octets'

Format of the input MPDU, specified as 'bits' or 'octets'.

Data Types: string

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

nonpositive integer

Status of MPDU decoding, returned as a nonpositive integer in the interval [–20, 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 the frame
–6	UnsupportedBAVariant	Unsupported variant of Block Ack frame
–7	UnknownBitmapSize	Unknown bitmap size
–8	UnknownAddressExtMode	Unknown address extension mode
–9	MalformedAMSDULength	Malformed aggregated 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 the A-MPDU
–15	CorruptedAMPDU	All the delimiters in the given A-MPDU failed the cyclic redundancy check (CRC)
–16	InvalidDelimiterLength	Invalid length field in MPDU delimiter
–17	MaxAMSDULenthExceeded	A-MSDU exceeded the maximum length limit
–18	MaxMPDULengthExceeded	MPDU exceeded the maximum length limit
–19	MaxMMPDULengthExceeded	MAC management frame exceeded the maximum length limit
–20	MaxMSDULengthExceeded	MSDU exceeded the maximum length limit

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

Data Types: int16

Extended Capabilities

C/C++ Code Generation
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