The overall data throughput in a 802.11n network is determined by applying the methods described above. A specific combination of modulation method, payload data rate and number of spatial streams is referred to as modulation coding scheme (MCS). Data throughput also depends on whether the short guard interval and channel bundling to 40 MHz are used.
802.11n uses the term "data throughput" instead of the term "data rate" used in older WLAN standards, because data rate is no longer an adequate description. The following table shows the maximum data throughput when using the short guard interval with 40 MHz channels.
The net data throughput, i.e. the actual number of IP packets transferred, can be up to 90 Mbps for one 802.11n data stream and, accordingly, for two spatial streams up to 180 Mbps. The net data throughput currently (early 2008) observed in practice is usually between 80 and 130 Mbps, depending on how mature the hardware and software are and also on how well the different manufacturers' chip sets work together.
| Data streams | Modulation | Payload data rate | Data throughput (GI=0.4 µs, 40 MHz) |
|---|---|---|---|
| 1 | BPSK | 1/2 | 15 |
| 1 | QPSK | 1/2 | 30 |
| 1 | QPSK | 3/4 | 45 |
| 1 | 16QAM | 1/2 | 60 |
| 1 | 16QAM | 3/4 | 90 |
| 1 | 64QAM | 1/2 | 120 |
| 1 | 64QAM | 3/4 | 135 |
| 1 | 64QAM | 5/6 | 150 |
| 2 | BPSK | 1/2 | 30 |
| 2 | QPSK | 1/2 | 60 |
| 2 | QPSK | 3/4 | 90 |
| 2 | 16QAM | 1/2 | 120 |
| 2 | 16QAM | 3/4 | 180 |
| 2 | 64QAM | 1/2 | 240 |
| 2 | 64QAM | 3/4 | 270 |
| 2 | 64QAM | 5/6 | 300 |