Wi-Fi Modulation Simulator
See how bits become a radio wave. Each group of bits picks a point on the constellation chart, and that point sets the height and timing of the carrier wave for one symbol, from BPSK to 4096-QAM.
How to use this tool controls and what to look for
Pick a modulation, press Play, and watch each group of bits land on a constellation point and shape the carrier wave. Then add noise.
Controls to change
- Modulation: step from BPSK (1 bit per symbol) up to 4096-QAM (12 bits per symbol).
- Signal-to-noise ratio: lower it to scatter the received points around their targets.
- Play: send symbols continuously, or use Next symbol to go one at a time.
- Show I and Q parts: split the carrier into its cosine (I) and sine (Q) parts.
- Bits (0 and 1 only): type your own bits, or press Random bits.
- 4 subcarriers: in OFDM: many subcarriers at once, switch between 4 and 8 subcarriers sent together.
What to look for
- Each step up in modulation packs the points closer together, so the same noise causes more errors.
- Received points that cross into a neighbour's area decode wrongly, but usually only one bit is wrong, because neighbours differ by one bit.
- Find the lowest signal-to-noise ratio at which each modulation still decodes cleanly: that is why high MCS values need a strong, clean signal.
About this tool
Modulation is how bits become a radio wave. Each group of bits picks one point on a constellation chart, and that point sets the amplitude and phase of the carrier for one symbol. This simulator shows constellations from BPSK to 4096-QAM, the resulting wave symbol by symbol, and many subcarriers at once as in OFDM. Add noise to see why dense modulations need a clean, strong signal.
What you'll learn
- How BPSK, QPSK and 16- to 4096-QAM map bits to amplitude and phase
- Why each step up carries more bits per symbol, from 1 bit (BPSK) to 12 bits (4096-QAM)
- Why neighbouring constellation points differ by only one bit
- Why noise limits the modulation a link can use, and where each one appears in the MCS table
Common questions
What modulation do Wi-Fi 6 and Wi-Fi 7 use?
Wi-Fi 6 goes up to 1024-QAM (10 bits per symbol on each subcarrier) and Wi-Fi 7 up to 4096-QAM (12 bits). Lower MCS values use BPSK, QPSK, 16-QAM and 64-QAM.
Why do high data rates need a strong signal?
Dense constellations put their points very close together, so a little noise makes the receiver pick the wrong one. The top modulations need a much higher signal-to-noise ratio, so they only work close to the access point.
What is a constellation diagram?
A chart of every point a modulation can send. The distance from the centre is the amplitude and the angle is the phase; each point stands for one pattern of bits.
Free for private and educational use. This interactive model is a simplified teaching aid and may contain mistakes. It is provided as is, without warranty. Use it to understand the concepts, not as a substitute for a site survey, vendor documentation or professional design advice.