A typical Wi-Fi home network includes laptops, tablets and phones, devices like modern printers, music devices and televisions. The majority of Wi-Fi networks are set up in "infrastructure mode", where the access point acts as a central hub to which Wi-Fi capable devices are connected. The devices do not communicate directly with each other (that is, in "ad-hoc mode"), but they go through the access point. Wi-Fi Direct devices are able to communicate with each other without requiring a dedicated wireless access point. The Wi-Fi Direct devices negotiate when they first connect to determine which device shall act as an access point.
Wi-Fi Aware is an interoperability certification program announced in January 2015 that enables device users, when in the range of a particular access point or another compatible device, to receive notifications of applications or services available in the proximity. Later versions of this standard included new features such as the capability to establish a peer-to-peer data connection for file transfer.
Wi-Fi Location is a type of Wi-Fi positioning system, and the certification could help providing accuracy to in-door positioning.
Formerly known as Carrier Wi-Fi, Wi-Fi Vantage is a certification program for operators to maintain and manges quality Wi-Fi connections in high usage environment. It includes a number of certification, such as Wi-Fi certified ac (as in 802.11ac), Passpoint, Agile Multiband, and Optimized Connectivity.
Wi-Fi EasyMesh is a certification program based on its Multi-Access Point specification for creating Wi-Fi meshes from products by different vendors, based on IEEE 1905.1. It is intended to address the problem of Wi-Fi systems that need to cover large areas where several routers serve as multiple access points, working together to form a larger/extended and unified network.
Conventional Wi-Fi networks are typically based on the presence of controller devices known as wireless access points. These devices normally combine three primary functions:
In October 2010, the Alliance began to certify Wi-Fi Direct, that allows Wi-Fi-enabled devices to communicate directly with each other by setting up ad-hoc networks, without going through a wireless access point or hotspot. Since 2009 when it was first announced, some suggested Wi-Fi Direct might replace the need for Bluetooth on applications that do not rely on Bluetooth low energy.
Wi-Fi Passpoint, alternatively known as Hotspot 2.0, is a solution for roaming between different Wi-Fi access points. It utilize IEEE 802.11u.
Wi-Fi HaLow is a standard for low-power wide-area (LPWA) connection standard using sub-1GHz spectrum for IoT devices. It is based on IEEE 802.11ah.
Wi-Fi also allows communications directly from one computer to another without an access point intermediary. This is called ad hoc Wi-Fi transmission. Different types of ad hoc network exist. In the simplest case network nodes must talk directly to each other. In more complex protocols nodes may forward packets, and nodes keep track of how to reach other nodes, even if they move around.
Wi-Fi Easy Connect is a protocol that would enable easily establishing connections via QR code.
Wi-Fi Home Design is a set of guideline released by Wi-Fi alliance for inclusion of wireless network in home design.
Ad-hoc mode was first invented and realized by Chai Keong Toh in his 1996 invention of Wi-Fi ad-hoc routing, implemented on Lucent WaveLAN 802.11a wireless on IBM ThinkPads over a size nodes scenario spanning a region of over a mile. The success was recorded in Mobile Computing magazine (1999) and later published formally in IEEE Transactions on Wireless Communications, 2002 and ACM SIGMETRICS Performance Evaluation Review, 2001.
Wi-Fi use can account for up to 60 percent of a smartphone’s energy consumption. When not connected to a network, Wi-Fi consumes energy because the device constantly searches for a signal.
The certification of Wi-Fi Agile Multiband indicate devices can automatically connect and maintain connection in the most suitable way. It cover the IEEE 802.11k standard about access point information report, the IEEE 802.11v standard that enable exchanging information about state of network, IEEE 802.11u standard about additional information of a Wi-Fi network, IEEE 802.11r about fast transition roaming between different access points, as well as other technologies specified by Wi-Fi alliance.
Another mode of direct communication over Wi-Fi is Tunneled Direct Link Setup (TDLS), which enables two devices on the same Wi-Fi network to communicate directly, instead of via the access point.
Similarly, the Wi-Fi Alliance promotes the specification Wi-Fi Direct for file transfers and media sharing through a new discovery- and security-methodology. Wi-Fi Direct launched in October 2010.
In most standard Wi-Fi routers, the three standards, a, b and g, are enough. But in long-range Wi-Fi, special technologies are used to get the most out of a Wi-Fi connection. The 802.11-2007 standard adds 10 MHz and 5 MHz OFDM modes to the 802.11a standard, and extend the time of cyclic prefix protection from 0.8 μs to 3.2 μs, quadrupling the multipath distortion protection. Some commonly available 802.11a/g chipsets support the OFDM 'half-clocking' and 'quarter-clocking' that is in the 2007 standard, and 4.9 GHz and 5.0 GHz products are available with 10 MHz and 5 MHz channel bandwidths. It is likely that some 802.11n D.20 chipsets will also support 'half-clocking' for use in 10 MHz channel bandwidths, and at double the range of the 802.11n standard.
IBSS with Wi-Fi Protected Setup would enable the creation of ad hoc network between devices directly without central access point.
A number of public Wi-Fi location databases are available (only active projects):