IEEE 802.11n introduces enhancements to the IEEE 802.11 standard, aiming to achieve higher data rates within both the 2.4 GHz and 5 GHz frequency bands.
The key improvements responsible for enabling these elevated data rates are as follows:
- Modifications to OFDM Implementation: IEEE 802.11n involves alterations in the implementation of the Orthogonal Frequency Division Multiplexing (OFDM) modulation scheme. These changes lead to an increase in data rates, elevating them from 54 Mbit/s to 65 Mbit/s.
- Channel Bonding: Channel bonding involves the combination of two standard 20 MHz channels into a wider 40 MHz channel, effectively doubling the data rate. However, this approach reduces the number of non-overlapping channels available, which can lead to increased interference from other networks. This issue is particularly prominent in the 2.4 GHz band, where the channel spacing is only 5 MHz (compared to 10 MHz in the 5 GHz band) and the available channels are limited.
- MIMO (Multiple Input Multiple Output): MIMO technology divides data into multiple data streams, which are then transmitted through separate antennas to corresponding antennas at the receiver. Doubling the number of data streams results in a corresponding doubling of the total data rate. IEEE 802.11n supports up to 4 data streams.It’s worth noting that most smartphones are equipped with a single transmitter to conserve battery power. This limitation reduces the maximum achievable data rate from 600 Mbit/s to 150 Mbit/s.
Achieving the maximum performance outlined by IEEE 802.11n is only feasible within a network exclusively composed of IEEE 802.11n devices. If the network includes a mix of IEEE 802.11a/b/g devices, the overall performance will be significantly lower.