WiFi Transfer Rates & Typesby Jacob Andrew
Wi-Fi connections look the same, but come in many flavors. Each Wi-Fi network is built on one of a series of standards put forth by the Institute for Electrical and Electronics Engineers. The IEEE classifies these standards under section 802.11, so each standard includes that number followed by one or more letters that identify that specific standard. Wi-Fi standards began with 802.11a, with the latest standard defined as 802.11ac.
The first Wi-Fi standard was 802.11a. This standard uses the 5 GHz unlicensed spectrum to achieve data rates up to 54 Mbps. This standard, though as fast as more modern standards, suffered from poor range. Following closely was IEEE 802.11b. This standard provided greater range and stability by using the 2.4 GHz wireless spectrum, but had a paltry theoretical maximum transfer rate of 11 Mbps.
The “g” standard represents one of the first, widely-adopted wireless standards. Using the 2.4 GHz spectrum, 802.11g achieves the range of 802.11b while reaching 802.11a’s maximum speed of 54 Mbps. As a bonus, 802.11b devices can connect to an 802.11g access point running in compatibility mode. The compatibility mode, however, forces 802.11g devices to run at a lower maximum rate.
The N standard had a tumultuous history. With wireless growing in popularity after 802.11g, vendors were eager to push a standard that would make wireless as fast as wired connections -- over 100 Mbps. Therefore, even as IEEE held off on ratifying the standards, numerous companies began pushing “draft” 802.11n standards that became popularly known as "Draft N." These draft standards utilized the same technologies but suffered from maximum speed and compatibility issues. Once ratified, 802.11n offered a Wi-Fi type that operated on both the 5 GHz and 2.4 GHz spectrum, and achieved a standard maximum speed of 144 Mbps. The maximum speed increases when the access point and adapter use Multiple In, Multiple Out technology. MIMO makes it possible to use up to three separate frequencies simultaneously, pushing the theoretical max to nearly 450 Mbps. This standard is backwards compatible with “g”, “b”, and “a” standards, meaning all such devices can connect to an 802.11n router.
Just as 802.11n began offering wired-network speeds over wireless, gigabit Ethernet became the wired norm. As a result, IEEE went back to work developing a standard that would offer gigabit speeds over wireless. Set for official publication in early 2014, manufacturers began releasing 802.11ac access points as early as 2013. The new standard uses the 5 GHz spectrum with MIMO technology to achieve speeds as high as 1.3 Gbps. All 802.11ac access points are required to include a 2.4 GHz antenna in order to maintain backwards compatibility with 802.11n.