wlanMPDUDecode

Description

example

[cfgMAC,payload,status] = wlanMPDUDecode(mpdu,cfgPHY) returns the MAC service data units (MSDUs), payload, by decoding the input MAC protocol data unit (MPDU), mpdu, for the given 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.

example

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

Examples

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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);

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');

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

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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

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

Data Types: string

Output Arguments

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MAC frame configuration, returned as a wlanMACFrameConfig object.

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 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 valueMember of enumeration classDecoding Status
0SuccessMAC frame successfully decoded
–1FCSFailedFrame check sequence (FCS) failed
–2InvalidProtocolVersionInvalid protocol version
–3UnsupportedFrameTypeUnsupported frame type
–4UnsupportedFrameSubtypeUnsupported frame subtype
–5NotEnoughDataInsufficient data to decode the frame
–6UnsupportedBAVariantUnsupported variant of Block Ack frame
–7UnknownBitmapSizeUnknown bitmap size
–8UnknownAddressExtModeUnknown address extension mode
–9MalformedAMSDULengthMalformed aggregated MAC service data unit (A-MSDU) with invalid length
–10MalformedSSIDMalformed service set identifier (SSID) information element (IE)
–11MalformedSupportedRatesIEMalformed supported rates IE
–12MalformedIELengthMalformed IE length field
–13MissingMandatoryIEsMandatory IEs missing
–14NoMPDUFoundNo MPDU found in the A-MPDU
–15CorruptedAMPDUAll the delimiters in the given A-MPDU failed the cyclic redundancy check (CRC)
–16InvalidDelimiterLengthInvalid length field in MPDU delimiter
–17MaxAMSDULenthExceededA-MSDU exceeded the maximum length limit
–18MaxMPDULengthExceededMPDU exceeded the maximum length limit
–19MaxMMPDULengthExceededMAC management frame exceeded the maximum length limit
–20MaxMSDULengthExceededMSDU 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
Generate C and C++ code using MATLAB® Coder™.

Introduced in R2019a