wlanAMPDUDeaggregate

Deaggregate A-MPDU and extract MPDUs

Syntax

[mpduList,delimiterCRCFail,status] = wlanAMPDUDeaggregate(ampdu,cfgPHY)

[mpduList,delimiterCRCFail,status] = wlanAMPDUDeaggregate(___,'DataFormat',format)

Description

[mpduList,delimiterCRCFail,status] = wlanAMPDUDeaggregate(ampdu,cfgPHY) returns mpduList, a list of medium access control (MAC) protocol data units (MPDUs), by deaggregating ampdu, an aggregate MPDU (A-MPDU), for physical layer (PHY) format configuration cfgPHY. The function also returns delimiterCRCFail, which indicates any delimiter cyclic redundancy check (CRC) failures for subframes found in ampdu, and status, the status of A-MPDU deaggregation.

[mpduList,delimiterCRCFail,status] = wlanAMPDUDeaggregate(___,'DataFormat',format) specifies the data format of the ampdu.

Examples

Deaggregate VHT-Format A-MPDU

Deaggregate a very-high-throughput-format (VHT-format) A-MPDU specified in bit form.

Create a WLAN MAC frame configuration object, specifying the frame type and format.

cfgMAC =  wlanMACFrameConfig('FrameType','QoS Data','FrameFormat','VHT');

Create a VHT-format configuration object with default settings.

cfgPHY = wlanVHTConfig;

Create a random payload of eight MSDUs and use it to generate an A-MPDU in octet form.

payload = repmat({randi([0 255],1,40)},1,8);
ampduOctets = wlanMACFrame(payload,cfgMAC,cfgPHY);

Convert the A-MPDU to bit form.

ampdu = reshape(de2bi(hex2dec(ampduOctets),8)',[],1);

Return the list of MPDUs by deaggregating the A-MPDU.

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

Deaggregate HT-Format A-MPDU

Deaggregate a high-throughput-format (HT-format) A-MPDU, specified in octet form.

Create a WLAN MAC frame configuration object, specifying the frame type, frame format, and MPDU aggregation.

cfgMAC = wlanMACFrameConfig('FrameType','QoS Data','FrameFormat','HT-Mixed','MPDUAggregation',1);

Create an HT-format configuration object, specifying MPDU aggregation.

cfgPHY = wlanHTConfig('AggregatedMPDU',1);

Create a random payload of eight MSDUs and use it generate an A-MPDU in octet form.

payload = repmat({randi([0 255],1,40)},1,8);
ampdu = wlanMACFrame(payload,cfgMAC,cfgPHY);

Return the list of MPDUs by deaggregating the A-MPDU.

[mpduList,delimiterCRCFail,status] = wlanAMPDUDeaggregate(ampdu,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

ampdu — A-MPDU to be deaggregated

binary vector | numeric vector | string scalar | character array

A-MPDU to be deaggregated, specified as one of these values:

• a binary vector representing the A-MPDU in bit format;

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

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

• a character vector representing the A-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

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

format — Format of the input A-MPDU

'bits' (default) | 'octets'

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

Data Types: string

Output Arguments

mpduList — List of MPDUs

cell array of character arrays

List of MPDUs, returned as a cell array of character arrays, where each character array corresponds to one MPDU. In these character arrays, each row is the hexadecimal representation of an octet.

If no MPDU delimiter is found in the input A-MPDU, the function returns mpduList as an empty cell array.

Data Types: cell

delimiterCRCFail — Delimiter CRC failure indicator

row vector of logical values

Delimiter CRC failure indicator, returned as a row vector of logical values. Each element of delimiterCRCFail indicates the delimiter CRC failure status for an A-MPDU subframe.

A value of 1 for the kth element of delimiterCRCFail indicates that the delimiter CRC failed for the kth A-MPDU subframe. In this case, the kth element of mpduList contains an MPDU that might be invalid.

A value of 0 for the kth element of delimiterCRCFail indicates that the delimiter CRC passed for the kth subframe. In this case, the kth element of mpduList contains a valid MPDU.

Data Types: logical

status — Status of A-MPDU deaggregation

nonpositive integer

Status of A-MPDU deaggregation, returned as a nonpositive integer in the interval [–20, 0]. Each enumeration value of status corresponds to a member of the wlanMACDecodeStatus enumeration class, which indicates the status of MAC frame parsing 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 A-MPDU deaggregation stopped because the input A-MPDU is corrupt or malformed.

Data Types: int16

Extended Capabilities

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