80211n

IEEE 802.11n is a wireless networking standard in the IEEE 802.11 family, ratified in 2009. It was designed to improve throughput and range over the 802.11a/b/g family while maintaining backward compatibility with those standards. The PHY layer introduces MIMO (multiple-input multiple-output) using OFDM (orthogonal frequency-division multiplexing), allowing transmissions over multiple antennas and spatial streams to increase data rates and reliability.

802.11n operates in the 2.4 GHz and 5 GHz bands and supports channel widths of 20 MHz or 40 MHz through channel bonding. The standard defines up to four spatial streams and, with 40 MHz channels and 64-QAM modulation, a theoretical maximum throughput of 600 Mbps. In practice, speeds are lower and depend on distance, interference, and device capabilities. The technology also improves range and robustness compared with earlier generations.

The standard is backward compatible with older 802.11 technologies, enabling coexistence with 802.11a/b/g devices in mixed networks. 802.11n was widely deployed in consumer routers and devices and served as the foundation for later amendments such as 802.11ac and 802.11ax. It is commonly marketed as Wi‑Fi 4, reflecting its place in the evolving naming scheme for wireless standards.