Barker, CCK, OFDM and OFDMA Compared
Four ways Wi-Fi has put bits on the air, from 1 Mbps in 1997 to Wi-Fi 6. Compare how Barker, CCK, OFDM and OFDMA build their signals, how much spectrum they need, and how they cope with echoes.
How to use this tool controls and what to look for
Pick a method and see how it builds its signal, how much spectrum it takes, and what an echo does to it.
Controls to change
- Method: choose Barker (1–2 Mbps), CCK (5.5–11 Mbps), OFDM (6–54 Mbps) or OFDMA (802.11ax).
- Next symbol: step through the symbols one at a time.
- 2.4 GHz channels 1, 6, 11: compare One channel with channels 1, 6 and 11, side by side. Tick Add channel 3 to see the overlap.
- Typical places: try a small room, an office, a warehouse or a large hall, or set the echo delay yourself.
- 802.11ax guard interval: choose 0.8, 1.6 or 3.2 µs for OFDMA.
What to look for
- Barker and CCK spread each bit across the whole 22 MHz channel. OFDM splits the channel into many slow subcarriers.
- A long echo overlaps the next Barker or CCK symbol, but OFDM absorbs it in the guard interval.
- OFDMA gives different clients different groups of subcarriers in the same transmission.
- The side-by-side table sums it up: data rates, symbol time, width and how each copes with echoes.
About this tool
Wi-Fi has put bits on the air in four main ways, from 1 Mbps in 1997 to Wi-Fi 6. This tool compares Barker coding, CCK, OFDM and OFDMA side by side: how each builds its signal, how the waveform and data rate relate, how much spectrum each needs, and how each copes with echoes.
What you'll learn
- How Barker spreading and CCK carried 1–11 Mbps in 802.11 and 802.11b
- How OFDM splits the channel into many slow subcarriers
- How OFDMA shares those subcarriers between clients
- Why OFDM copes with echoes far better than the older methods
Common questions
What is the difference between DSSS and OFDM?
DSSS (Barker and CCK) spreads one fast signal across the whole channel. OFDM sends many slower subcarriers side by side, which copes much better with echoes and reaches far higher rates.
Why did Wi-Fi move from CCK to OFDM?
CCK topped out at 11 Mbps and struggles with long echoes. OFDM, in 802.11a and g, reached 54 Mbps and is the basis of every later generation.
Is OFDMA faster than OFDM?
Not for one client. OFDMA lets several clients share one transmission, which cuts waiting and overhead when many devices send small amounts of data.
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.