i‑Fi technology is based on the IEEE 802.11TM series of wireless connectivity standards that have revolutionized how we communicate and access information. Today, billions of Wi‑Fi-enabled devices are in use worldwide, dramatically impacting how individuals, businesses, government agencies, and societies interact. It is no exaggeration to say that the IEEE 802.11 series of standards has significantly supported the deployment of high-quality global communications Wi‑Fi technologies through inexpensive, equitable internet access.
Since its debut 25 years ago, Wi‑Fi has played a vital role in helping us be connected at home, work, and in public places. You may recall a time when Wi‑Fi wasn’t so readily available, but today we expect a standard level of connectivity wherever we go – even in large outdoor spaces such as parks and baseball stadiums. Typical of technology, the earliest versions of Wi‑Fi were considered slow by today’s standards and its use was more limited. Today, we now use an enormous number of Wi‑Fi-enabled devices – computers, smartphones, game consoles, health/fitness devices, and much more – for productivity, organization, entertainment, health, and even security.
In recognition of the Internet’s 40th anniversary, we examine how the IEEE 802.11 series of standards has driven the evolution of Wi‑Fi technology and how new additions to the series will enable greater Wi‑Fi capabilities, making innovative new applications possible.
The origins of Wi‑Fi can be traced back to a 1985 ruling by the U.S. Federal Communications Commission that released the bands of the radio spectrum at 900 megahertz (MHz), 2.4 gigahertz (GHz), and 5.8 GHz for unlicensed use by anyone. Technology companies built wireless networks and devices to take advantage of the newly available radio spectrum, but the lack of a common technical standard resulted in fragmentation because manufacturers’ devices were rarely compatible.
In 1997, IEEE SA unveiled its groundbreaking IEEE 802.11TM technical standard and introduced Wi‑Fi to the market, enabling wireless data transmission at up to 2 Mbit/s using an unlicensed 2.4 GHz radio spectrum.
The promising Wi‑Fi technology and a new common technical standard were embraced by technology innovators, particularly Apple’s then-CEO Steve Jobs, who was enamored by the idea of wireless connectivity for laptops. This led to Wi‑Fi’s first major commercial breakthrough in 1999 when Jobs and Apple introduced the first mass-marketed consumer products with Wi‑Fi connectivity, the AirPort wireless base station, and iBook. At that time, the newly released IEEE 802.11bTM amendment to the original Wi‑Fi standard pushed theoretical data rates up to 11 Mbit/s. Jobs showed off the world’s first Wi‑Fi-enabled laptop at MacWorld in New York City, demonstrating wireless Internet by passing the iBook through a hula hoop to a cheering crowd.
The evolution of IEEE 802.11-based Wi‑Fi standards continues today, providing much faster data transmission rates, longer ranges, and more reliable and secure connections. All IEEE 802.11 standard amendments are constructed in a manner such that devices which operate according to their specifications will be backward compatible with earlier versions, enabling any modern IEEE 802.11-based device to communicate with older products.
- IEEE 802.11TM is the aforementioned pioneering 2.4 GHz Wi‑Fi standard from 1997, and it is still referred to by that nomenclature. This standard and its subsequent amendments are the basis for Wi‑Fi wireless networks and represent the world’s most widely used wireless computer networking protocols.
- IEEE 802.11bTM, or Wi‑Fi 1, was introduced in 1999 with Apple’s announcement of its Wi‑Fi-enabled base station and laptop computer. It also operated at 2.4 GHz, but it incorporated modulation schemes called direct-sequence spread spectrum/complementary code keying (DSSS/CCK). This helped reduce interference from devices such as microwave ovens, cordless phones, baby monitors, and other sources, and it also achieved higher data rates. Wi‑Fi 1 enabled wireless communications at distances of ~38m indoors and ~140m outdoors.
- IEEE 802.11aTM, or Wi‑Fi 2, also introduced in 1999, was the successor to IEEE 802.11b. It was the first Wi‑Fi specification to feature a multi-carrier modulation scheme (OFDM) to support high data rates, unlike Wi‑Fi 1’s single-carrier design. It supported 5 GHz operation and its 20 MHz bandwidth supported multiple data rates.
- IEEE 802.11gTM, or Wi‑Fi 3, was introduced in 2003. Wi‑Fi 3 achieved faster data rates of up to 54 Mbit/s in the same 2.4 GHz frequency band as IEEE 802.11b, made possible by an OFDM multi-carrier modulation scheme and other enhancements. Additionally, Wi‑Fi 3 appealed to mass market manufacturers and users because 2.4 GHz devices were less expensive than 5 GHz devices.
- IEEE 802.11nTM, or Wi‑Fi 4, was introduced in 2009. Wi‑Fi 4 supported the 2.4 GHz and 5GHz frequency bands, with up to 600 Mbit/s data rates, multiple channels within each frequency band, and other features. IEEE 802.11n data throughputs enabled the use of WLAN networks in place of wired networks, a significant feature, enabling new use cases and reducing operational costs for end users and IT organizations.
- IEEE 802.11acTM, or Wi‑Fi 5, was introduced in 2013. Wi‑Fi 5 supported data rates at up to 3.5 Gbit/s, with still-greater bandwidth, additional channels, better modulation, and other features. This was the first Wi‑Fi standard to enable the use of multiple input/multiple output (MIMO) technology, which enabled multiple antennas to be used on both sending and receiving devices to reduce errors and boost speed.
Although the theoretical data rate for Wi‑Fi 6 is 9.6 Gbit/s, this standard is more focused on usage density rather than boosting speed. The pervasive use of Wi‑Fi today creates issues whereby network performance can be degraded in areas of dense Wi‑Fi traffic. Examples of problem areas include sports stadiums, concert halls, and public transportation hubs. But the issue isn’t only in large venues. Homes are increasingly problematic due to the need for routers that must communicate simultaneously with a growing number of digital gadgets.
IEEE 802.11ax offers many enhancements including a multi-user mechanism that allows the 9.6 Gbit/s data rate to be split among various devices. It also supports routers sending data to multiple devices in one broadcast frame over the air, and it allows Wi‑Fi devices the ability to schedule transmissions to the router. Mechanisms to support longer-range outdoor operations are also added.
Collectively, these features improve aggregate throughput and support the increasing use of Wi‑Fi in data-heavy situations and in applications such as video and cloud access, where real-time performance and low power consumption for battery-powered devices are required. Of great importance and focus is the expectation for high-definition video to be the dominant type of traffic in many forthcoming Wi‑Fi deployments.
There are numerous drivers for even faster, better Wi‑Fi, including the rapid growth and adoption of the Internet of Things (IoT), with more devices expanding their capabilities through connectivity. Sensor technology embedded in IoT devices continues to become less expensive, more advanced, and more widely available. In turn, widespread availability and cost-effectiveness are pushing innovation of new sensor applications, including large-scale monitoring and detection.
For enterprises, Wi‑Fi 7 will benefit IoT and IIoT applications, such as industrial automation, surveillance, remote control, AV/VR, and other video-based applications. Additionally, Wi‑Fi 7 brings more flexibility and capabilities to enterprises as they engage in digital transformation.
Wi‑Fi 7 is based on features defined in the IEEE P802.11beTM draft amendment. A major evolutionary milestone in Wi‑Fi technology, Wi‑Fi 7 will provide quadruple – that’s four times – faster data rates (~40 Gbit/s) and twice the bandwidth (320 MHz channels vs. 160 MHz channels for Wi‑Fi 6). Wi‑Fi 7 also supports more efficient and reliable use of available and contiguous spectrum through multi-band/multi-channel aggregation and other means. The standard features numerous enhancements to MIMO protocols and many other advancements and refinements of existing Wi‑Fi capabilities.
The Wi‑Fi 7 specification also features multi-link operation (MLO), which is similar to the carrier aggregation that mobile phone providers use to increase data throughput by combining the abilities of separate channels. MLO can elevate data rates to be seven times faster while also lowering latency and improving dependability because linked channels work in parallel.
Wi‑Fi 7 also doubles Wi‑Fi 6’s eight independent streams of data to 16 spatial streams. It uses coordinated multiuser MIMO (CMU-MIMO), which is a significant improvement from multi-user multiple‑input, multiple-output.
The new Wi‑Fi 7 specification also uses multi-user resource unit (MRU) to avoid interference, allowing selective puncturing of overlapping portions of the spectrum to let the data flow only on frequencies that are clear. It can help raise data rates and reliability in congested Wi‑Fi environments, such as in an apartment building or large office environment.
Summing up, from the user’s perspective, Wi‑Fi 7 will be much faster, have much lower latency, will support many more devices, and will perform much better in congested Wi‑Fi spaces and where Wi‑Fi networks overlap. Of course, to harness the benefits, users will need significantly faster internet speeds from their service providers.
But the IEEE 802.11 series work doesn’t end here. The drive to improve Wi‑Fi is a continuous focus of IEEE SA and its army of volunteer experts.
- The Artificial Intelligence/Machine Learning Topic Interest Group (AIML TIG) is focused on describing use cases for artificial intelligence/machine learning (AI/ML) applicability in 802.11 systems and investigating the technical feasibility of features enabling support of AI/ML. Developers and deployers of AI/ML protocols over wireless networks are expected to benefit from more optimized and efficient support for exchanging AI/ML-related data exchanges, such as reduced overhead and reduced delay. WLAN users, OEMs, and network operators are expected to benefit from improved user experience and higher efficiency of resources, and improved network performance.
- The Ambient Power for WLAN IoT Topic Interest Group (AMP TIG) is describing use cases for 802.11 ambient power-enabled IoT devices and investigating the technical feasibility of features to enable 802.11 WLAN support of ambient power-enabled IoT devices. Battery-free IoT technologies are expected to significantly reduce maintenance efforts of IoT networks and devices and extend the application scenarios featured as more environmentally friendly and much safer. This technology would see application in verticals such as agriculture, Smart Grid, mining, manufacturing, logistics, smart home, transportation, etc.
- The Ultra High Reliability (UHR) Study Group is investigating technology that may improve the reliability of WLAN connectivity, reduce latencies, increase manageability, increase throughput including at different SNR levels, and reduce device-level power consumption. Due to the growing importance of metaverse and AR/VR communications, the need for more throughput/data rate is in constant evolution. The study group started early in 2023; a task group is targeted to start in May 2023.
We welcome the involvement of participants from academia, government, and industry. For more information or to join the standards activity, please visit the IEEE 802 LAN/MAN Standards Committee webpage (https://standards.ieee.org).