Generate WLAN Waveforms

Generate standard-compliant IEEE 802.11 waveforms for device testing, link-level simulation, or signal analysis. This skill covers the transmit chain: configure the PHY format, size the payload, generate the time-domain IQ waveform, and plot.

When to Use

• Generating WLAN/Wi-Fi test waveforms for any 802.11 standard
• Creating the transmit side of a link-level simulation
• Building packets with specific MAC frame types (Data, Block Ack, Beacon, etc.)
• Configuring OFDMA resource unit allocations (HE-MU, EHT-MU, or UHR-MU)
• Configuring MU-MIMO transmissions (VHT, HE, EHT, UHR)
• UHR features: UEQM (per-stream MCS), DRU, LDPC2x, ELR (enhanced long range)
• Targeting a specific packet duration or transmit time

When NOT to Use

• Channel modeling, receiver processing, EVM/spectral mask — not covered
• Non-WLAN waveforms (5G NR, LTE, Bluetooth)

UHR (802.11bn) requires R2026a or later. If the user requests a UHR waveform and their release is older, inform them that UHR support was introduced in R2026a and recommend upgrading.

Workflow

Every waveform generation follows this pipeline:

1. Select format → create the config object (see Format Selection)
2. Configure PHY → set bandwidth, MCS, spatial streams, antennas
3. Size the payload → set PSDU/APEP length directly or from a target duration
4. Create payload bits → random bits or MAC frame via wlanMACFrame
5. Generate waveform → wlanWaveformGenerator(bits, cfg)
6. Plot and verify → time-domain magnitude, showAllocation for HE/EHT/UHR configs

Format Selection

For OFDMA formats (HE-MU, EHT-MU), the constructor takes allocation indices, not RU sizes. See references/he-allocation-indices.md and references/eht-allocation-indices.md.

UHR (802.11bn / Wi-Fi 8) uses example helper files, not built-in toolbox objects. Copy helpers into the script's working folder with setupExample("wlan/UHRParameterizationExample", scriptFolder). UHR supports UEQM (per-stream MCS), DRU, LDPC2x, ELR (enhanced long range), and new MCS values (15-23). Same allocation indices as EHT. See references/uhr-waveform-generation.md.

See Critical Rules for format-specific constraints (allocation index schemes, HT MCS encoding, DSSS properties).

EHT DUP mode duplicates the signal across subchannels for robust coverage. Set at construction: wlanEHTMUConfig("CBW80", EHTDUPMode=true). Constraints: MCS 14 (BPSK-DCM) only, single user, 1 spatial stream, no puncturing, 80/160/320 MHz. EHTDUPMode is read-only after construction.

Duration Targeting

Calculate payload size from target duration. All values are integer microseconds.

Duration argument is integer microseconds, not seconds. Pass 2000, not 2e-3.

MU Duration Targeting (iterative)

For any MU config (homogeneous users — same MCS, RU size, and spatial streams):

targetDuration = 1e-3; apepLen = 2000; % initial guess
for iter = 1:10
    for u = 1:numUsers, cfg.User{u}.APEPLength = apepLen; end
    txTime = transmitTime(cfg);
    if abs(txTime - targetDuration)/targetDuration < 0.01, break; end
    apepLen = round(apepLen * targetDuration / txTime);
end

Heterogeneous users (different MCS/RU/STS): Lowest-capacity user sets duration. Set per-user APEPLength based on traffic demand; use transmitTime(cfg).

PSDU Length Access

The way to get PSDU length varies by format. Using the wrong pattern throws errors.

`getPSDULength` and `psduLength` are not interchangeable. HE uses getPSDULength. EHT uses psduLength.

Key Functions

If you need to verify property names, check valid values for a config object, or look up parameters not covered in this skill, consult the online documentation links in references/documentation-links.md.

Patterns

Single-User Waveform with Target Duration

cfg = wlanVHTConfig;
cfg.ChannelBandwidth = 'CBW80';
cfg.MCS = 9;
cfg.NumTransmitAntennas = 4;
cfg.NumSpaceTimeStreams = 4;
cfg.SpatialMapping = 'Fourier';

% Size payload for 2 ms transmit time
cfg.APEPLength = wlanAPEPLength(cfg, 'TxTime', 2000);

% Generate waveform: 3 packets, 20 us idle
psduBits = randi([0 1], cfg.PSDULength * 8, 1);
waveform = wlanWaveformGenerator(psduBits, cfg, ...
    'NumPackets', 3, 'IdleTime', 20e-6);

fs = wlanSampleRate(cfg);

DSSS (802.11b) Waveform

cfg = wlanNonHTConfig;
cfg.Modulation = 'DSSS';
cfg.DataRate = '11Mbps';   % '1Mbps', '2Mbps', '5.5Mbps', or '11Mbps'
cfg.PSDULength = 1000;

psduBits = randi([0 1], cfg.PSDULength * 8, 1);
waveform = wlanWaveformGenerator(psduBits, cfg);
fs = wlanSampleRate(cfg);  % 11 MHz (chip rate)

HE-MU OFDMA Waveform

For OFDMA, the constructor takes allocation indices per 20 MHz subchannel. Read references/he-allocation-indices.md for the full index-to-RU mapping.

% 80 MHz, four 242-tone RUs (index 192 = one 242-tone RU per subchannel)
cfg = wlanHEMUConfig([192 192 192 192]);
cfg.NumTransmitAntennas = 4;

% Configure per-user parameters
for u = 1:4
    cfg.User{u}.MCS = u + 6;               % MCS 7, 8, 9, 10
    cfg.User{u}.NumSpaceTimeStreams = 1;
    cfg.User{u}.APEPLength = 4000;
    cfg.User{u}.ChannelCoding = 'LDPC';
end

% Use Fourier spatial mapping when NumSTS < NumTransmitAntennas per RU
for r = 1:numel(cfg.RU)
    cfg.RU{r}.SpatialMapping = 'Fourier';
end

% Generate PSDU bits per user
psduLen = getPSDULength(cfg);
txData = cell(1, numel(psduLen));
for u = 1:numel(psduLen)
    txData{u} = randi([0 1], psduLen(u) * 8, 1);
end

waveform = wlanWaveformGenerator(txData, cfg);
showAllocation(cfg);

Common HE allocation indices (per 20 MHz subchannel):

For 40 MHz, provide 2 indices. For 80 MHz, provide 4. For 160 MHz, provide 8.

EHT-MU OFDMA Waveform (with MRU)

EHT allocation indices support Multi-Resource Units (MRU) — non-contiguous tone blocks assigned to a single user. Read references/eht-allocation-indices.md for the full mapping.

% 80 MHz: 484+242 MRU on subchannels 1-3, 106+26+106 on subchannel 4
% Index 120 = 484+242 MRU (1 MU-MIMO user), 29/28 = continuation, 25 = 106+26+106
cfg = wlanEHTMUConfig([120 29 28 25]);
cfg.NumTransmitAntennas = 2;

% Set APEPLength appropriate to RU size (26-tone RUs have low throughput)
apepPerUser = [2000, 500, 100, 500]; % MRU, 106-tone, 26-tone, 106-tone
mcsPerUser  = [7, 4, 2, 4];
for u = 1:numel(cfg.User)
    cfg.User{u}.APEPLength = apepPerUser(u);
    cfg.User{u}.MCS = mcsPerUser(u);
    cfg.User{u}.NumSpaceTimeStreams = 1;
    cfg.User{u}.ChannelCoding = 'LDPC';
end

for r = 1:numel(cfg.RU)
    cfg.RU{r}.SpatialMapping = 'Fourier';
end

% EHT uses psduLength(), NOT getPSDULength()
psduLens = psduLength(cfg);
txData = cell(1, numel(psduLens));
for u = 1:numel(psduLens)
    txData{u} = randi([0 1], psduLens(u) * 8, 1);
end

waveform = wlanWaveformGenerator(txData, cfg);
showAllocation(cfg);

EHT continuation indices: When an RU spans multiple 20 MHz subchannels, use continuation indices for the additional subchannels:

• 28 — subchannel is part of a larger 242-tone allocation
• 29 — subchannel is part of a 484-tone allocation
• 30 — subchannel is part of a 996-tone allocation

VHT MU-MIMO Waveform

cfg = wlanVHTConfig;
cfg.ChannelBandwidth = 'CBW80';
cfg.NumUsers = 2;
cfg.NumTransmitAntennas = 4;
cfg.NumSpaceTimeStreams = [2 2];
cfg.MCS = [8 8];
cfg.APEPLength = [1024 1024];
cfg.GroupID = 2;                    % MU-MIMO: must be 1-62
cfg.SpatialMapping = 'Fourier';    % Required when total STS < NumTxAntennas

psduLen = cfg.PSDULength;           % Read-only vector for MU
txData = cell(1, cfg.NumUsers);
for u = 1:cfg.NumUsers
    txData{u} = randi([0 1], psduLen(u) * 8, 1);
end

waveform = wlanWaveformGenerator(txData, cfg);

Non-OFDMA MU-MIMO Waveform (EHT and HE)

When the user requests MU-MIMO without OFDMA (all users share a single full-bandwidth RU), use these patterns. If the user says "MU-MIMO" without mentioning OFDMA or multiple RUs, default to non-OFDMA.

EHT — use the string constructor (no allocation indices needed):

% 80 MHz, 2 MU-MIMO users on a single 996-tone RU (non-OFDMA)
cfg = wlanEHTMUConfig("CBW80", NumUsers=2);
cfg.NumTransmitAntennas = 4;
cfg.User{1}.NumSpaceTimeStreams = 2;
cfg.User{1}.MCS = 9;
cfg.User{1}.APEPLength = 4000;
cfg.User{1}.ChannelCoding = 'LDPC';
cfg.User{2}.NumSpaceTimeStreams = 2;
cfg.User{2}.MCS = 7;
cfg.User{2}.APEPLength = 4000;
cfg.User{2}.ChannelCoding = 'LDPC';
cfg.RU{1}.SpatialMapping = 'Fourier';

psduLens = psduLength(cfg);
txData = cell(1, numel(psduLens));
for u = 1:numel(psduLens)
    txData{u} = randi([0 1], psduLens(u) * 8, 1);
end
waveform = wlanWaveformGenerator(txData, cfg);

Valid bandwidths: "CBW20", "CBW40", "CBW80", "CBW160", "CBW320". Up to 8 users. Supports puncturing via PuncturedChannelFieldValue.

HE — no string constructor; use full-band allocation indices:

Follow the same per-user/per-RU pattern as EHT above, using getPSDULength(cfg) instead of psduLength(cfg). Example: cfg = wlanHEMUConfig([209 115 115 115]) for 80 MHz with 2 users.

MAC Frame Payload

See references/mac-frame-properties.md for:

• Argument order, payload format (hex octets), and PHY config requirements
• Frame types, properties, and aggregation (A-MSDU, A-MPDU)
• Common mistakes and calling conventions

Multi-Packet Waveforms

See references/multi-packet-waveforms.md for:

• A-MPDU aggregation with wlanMSDULengths (cell array of uint8 MSDUs)
• Multi-packet waveforms — identical (NumPackets, IdleTime) or mixed-format

concatenation with SIFS/DIFS/PIFS spacing

Quick reference — inter-frame spacing: SIFS=16 μs, DIFS=34 μs, PIFS=25 μs.

Trigger-Based (TB) Uplink

See references/trigger-based-uplink.md for:

• HE TB (wlanHETBConfig), EHT TB (wlanEHTTBConfig), UHR TB (uhrTBConfig)
• RUSize/RUIndex from ruInfo(cfgMU), LTF symbols, OversamplingFactor
• UHR DRU — distributed resource units with DBW/RU size rules

Conventions

• After generating a waveform, unless the user asks for something specific:

1. Tell the user the waveform variable name, size, and sample rate
2. Plot the time-domain waveform magnitude with a time axis in milliseconds
3. For HE, EHT, or UHR configurations, call showAllocation(cfg)
4. Save the generation code as a plain-text Live Code `.m` file using the

matlab-create-live-script skill format (%[text] markup, %% sections, required appendix). Open it in the editor with edit('scriptName.m').

• UHR scripts use a working folder — copy helpers into the same folder as

the script with setupExample. See references/uhr-waveform-generation.md.

• Single-user payload is a plain column vector — use a cell array only for

multi-user. wlanWaveformGenerator(bits, cfg) not wlanWaveformGenerator({bits}, cfg).

• Always use `wlanSampleRate(cfg)` — never hardcode. For UHR configs use

wlanSampleRate(cfg.ChannelBandwidth) (UHR objects are not yet supported).

• OFDMA bandwidth is read-only — inferred from allocation index vector

length (1→20, 2→40, 4→80, 8→160 MHz).

• Units: IdleTime in seconds (20e-6). Duration functions in integer

microseconds (2000). OversamplingFactor multiplies wlanSampleRate. transmitTime(cfg, 'microseconds') — use the unit argument for display, not * 1e6. Valid units: 'seconds', 'milliseconds', 'microseconds', 'nanoseconds'.

• Verify multi-user configs with `ruInfo(cfg)` — after constructing any

OFDMA or MU-MIMO config, call ruInfo and check NumUsers, NumUsersPerRU, and RUSizes match what was requested. Wrong allocation indices silently produce wrong user counts.

• ruInfo: HE returns numeric arrays. EHT returns cell arrays (MRU support).
• Plotting: tiledlayout/nexttile (not subplot).

showAllocation(cfg, ax) embeds in existing layout.

Critical Rules

These constraints cause the most errors. Check them before calling wlanWaveformGenerator.

PSDU Length Method Varies by Format

Using the wrong accessor throws "Undefined function" or silent wrong results.

Allocation Indices Are Not RU Sizes

wlanHEMUConfig(242) is invalid. Use wlanHEMUConfig(192) for a 242-tone RU. wlanEHTMUConfig(242) is also invalid — use wlanEHTMUConfig(64). Always consult the allocation index reference tables.

HE and EHT use completely different index schemes. A 242-tone RU is index 192 for HE but index 64 for EHT. Never mix them.

HE-MU multi-subchannel RU indices signal users per content channel — see references/he-allocation-indices.md.

Preamble Puncturing vs STAID=2046

STAID=2046 does not puncture — it only disables one user's data.

Non-OFDMA puncturing uses PuncturedChannelFieldValue (1–4 for 80 MHz, mapping to subchannels 1–4). Must be set at construction: wlanEHTMUConfig("CBW80", NumUsers=2, PuncturedChannelFieldValue=3)

Spatial Mapping Rules

NumSpaceTimeStreams < NumTransmitAntennas per RU  →  SpatialMapping = 'Fourier'
NumSpaceTimeStreams == NumTransmitAntennas         →  SpatialMapping = 'Direct'

Using 'Direct' when STS < antennas causes a dimension mismatch error.

Non-OFDMA Is the Default for MU-MIMO

When the user says "MU-MIMO" without mentioning OFDMA or multiple RUs, default to non-OFDMA (single full-bandwidth RU shared by all users):

• EHT: wlanEHTMUConfig("CBW80", NumUsers=N)
• HE: Full-band allocation indices (see Patterns section)

Trigger-Based RUIndex From ruInfo

TB config RUIndex values are subcarrier-based positions from `ruInfo(cfgMU).RUIndices`, not sequential RU numbers. Using wrong indices causes subcarrier overlap errors.

Construction-Time-Only Properties

EHTDUPMode, PuncturedChannelFieldValue, and NumUsers on wlanEHTMUConfig are read-only after construction — pass them as name-value pairs in the constructor. See references/eht-allocation-indices.md for the full list and examples.

Format-Specific Constraints

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