Wi-Fi Direct
Encyclopedia
Wi-Fi Direct is a standard that allows Wi-Fi
devices to talk to each other without the need for wireless access point
s (hot spots).
s, "base stations" or "hot spots". These devices normally combine three primary functions; physical support for wireless and wired networking, bridging and routing between devices on the network, and service provisioning to add and remove devices from the network.
A typical Wi-Fi home network includes a wired connection to a broadband
provider, the access point, computers connected by wired and wireless connections, and sometimes other devices on the network. 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, but they go through the access point. All Wi-Fi Direct devices are able to operate as either a device or an access point. The Wi-Fi Direct devices negotiate when they first connect to determine which device acts as an access point.
A common example is the Wi-Fi Protected Setup
system included in most access points built since 2007 when the standard was introduced. Wi-Fi Protected Setup allows access points to be set up simply by entering a PIN or other identification into a connection screen, or in some cases, simply by pressing a button. The Protected Setup system uses this information to send data to a computer, handing it the information needed to complete the network setup and connect to the internet. From the user's point of view, a single click replaces the multi-step, multi-device, jargon-filled setup experience formerly required.
While the Protected Setup model works as intended, it was intended only to simplify the connection between the access point and the devices that would make use of its services, primarily accessing the internet. It provides little help within a network, finding and setting up printer access from a computer for instance. To address those roles, a number of different protocols have developed, including Universal Plug and Play
(UPnP), Devices Profile for Web Services
(DPWS), and Apple's Bonjour
. These protocols allow devices to seek out other devices within the network, query their capabilities, and provide some level of automatic setup.
s to include Wi-Fi as a standard feature, and over time it has become common in feature phone
s as well. The process of adding Wi-Fi to smaller devices has accelerated, and it is now possible to find printers, camera
s, scanner
s and many other common devices with Wi-Fi in addition to other connections, like USB.
The widespread adoption of Wi-Fi in new classes of smaller devices has made the need for working ad hoc networking much more important. Even without a central Wi-Fi hub/router, it would be useful for a laptop computer to be able to wirelessly connect to a local printer. Although the ad hoc mode was created to address this sort of need, the lack of additional information for discovery makes it difficult to use in practice.
Although systems like UPnP and Bonjour provide many of the needed capabilities and are included in some devices, a single widely supported standard was lacking, and support within existing devices was far from universal. A guest using their smart phone would likely be able to find a hot spot and connect to the Internet with ease, perhaps using Protected Setup to do so. But the same device would find streaming music to a computer or printing a file might be difficult, or simply not supported between differing brands of hardware.
When a device enters the range of the Wi-Fi Direct host, it can connect to it using the existing ad-hoc protocol, and then gather setup information using a Protected Setup-style transfer. Connection and setup is so simplified that some suggest it may replace Bluetooth
in some situations.
Soft AP's can be as simple or as complex as the role requires. A digital picture frame might provide only the most basic services needed to allow digital cameras to connect and upload images. A smart phone that allows data tethering might run a more complex soft AP that adds the ability to bridge to the Internet. The standard also includes WPA2 security and features to control access within corporate networks.
Wi-Fi Direct-certified devices can connect one-to-one or one-to-many and not all connected products need to be Wi-Fi Direct-certified. One Wi-Fi Direct enabled device can connect to legacy Wi-Fi certified devices.
The Wi-Fi Direct certification program is developed and administered by the Wi-Fi Alliance
, the industry group that develops the standards suite underlying the Wi-Fi CERTIFIED certification program and owns the "Wi-Fi" trademark
. The final specification has not been released, and certain aspects of the system have not been mentioned to date. For instance, the system used for discovery and device classification, an analogue of UPnP or Bonjour
, has not been mentioned in existing references.
The first Wi-Fi Direct certified smart phone was the Samsung Galaxy S (GT-I9000). (Nov 2010)
' chipset is Wi-Fi Direct certified in November,2010. Google announced Wi-fi Direct support in Android 4.0 in October, 2011. While some Android 2.3 devices have had this feature through proprietary operating system extensions developed by OEMs, the Galaxy Nexus
was the first Android device to ship with Google's implementation of this feature and an API for developers to use for application development.
Wi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
devices to talk to each other without the need for wireless access point
Wireless access point
In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards...
s (hot spots).
Basic Wi-Fi
Conventional Wi-Fi networks are typically based on the presence of controller devices known as wireless access pointWireless access point
In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards...
s, "base stations" or "hot spots". These devices normally combine three primary functions; physical support for wireless and wired networking, bridging and routing between devices on the network, and service provisioning to add and remove devices from the network.
A typical Wi-Fi home network includes a wired connection to a broadband
Broadband
The term broadband refers to a telecommunications signal or device of greater bandwidth, in some sense, than another standard or usual signal or device . Different criteria for "broad" have been applied in different contexts and at different times...
provider, the access point, computers connected by wired and wireless connections, and sometimes other devices on the network. 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, but they go through the access point. All Wi-Fi Direct devices are able to operate as either a device or an access point. The Wi-Fi Direct devices negotiate when they first connect to determine which device acts as an access point.
Automated setup
As the number and type of devices attaching to Wi-Fi systems increased, the basic model of a simple router with smart computers became increasingly strained. At the same time, the increasing sophistication of the hot spots presented setup problems for the users. To address these problems, there have been numerous attempts to simplify certain aspects of the setup task.A common example is the Wi-Fi Protected Setup
Wi-Fi Protected Setup
Wi-Fi Protected Setup is a computing standard for easy and secure establishment of a wireless home network....
system included in most access points built since 2007 when the standard was introduced. Wi-Fi Protected Setup allows access points to be set up simply by entering a PIN or other identification into a connection screen, or in some cases, simply by pressing a button. The Protected Setup system uses this information to send data to a computer, handing it the information needed to complete the network setup and connect to the internet. From the user's point of view, a single click replaces the multi-step, multi-device, jargon-filled setup experience formerly required.
While the Protected Setup model works as intended, it was intended only to simplify the connection between the access point and the devices that would make use of its services, primarily accessing the internet. It provides little help within a network, finding and setting up printer access from a computer for instance. To address those roles, a number of different protocols have developed, including Universal Plug and Play
Universal Plug and Play
Universal Plug and Play is a set of networking protocols for primarily residential networks without enterprise class devices that permits networked devices, such as personal computers, printers, Internet gateways, Wi-Fi access points and mobile devices to seamlessly discover each other's presence...
(UPnP), Devices Profile for Web Services
Devices Profile for Web Services
The Devices Profile for Web Services defines a minimal set of implementation constraints to enable secure Web Service messaging, discovery, description, and eventing on resource-constrained devices....
(DPWS), and Apple's Bonjour
Bonjour (software)
In computing, Bonjour is Apple Inc.'s trade name for its implementation of Zeroconf, a group of technologies that includes service discovery, address assignment, and name resolution...
. These protocols allow devices to seek out other devices within the network, query their capabilities, and provide some level of automatic setup.
New uses
It has become increasingly common for smart phones and portable media playerPortable media player
A portable media player or digital audio player, is a consumer electronics device that is capable of storing and playing digital media such as audio, images, video, documents, etc. the data is typically stored on a hard drive, microdrive, or flash memory. In contrast, analog portable audio...
s to include Wi-Fi as a standard feature, and over time it has become common in feature phone
Feature phone
A feature phone is a mobile phone that, like smartphones, combines the functions of a personal digital assistant and a mobile phone.Today's models typically also serve as portable media players and camera phones with touchscreen, GPS navigation, Wi-Fi and mobile broadband access.Feature phones is...
s as well. The process of adding Wi-Fi to smaller devices has accelerated, and it is now possible to find printers, camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
s, scanner
Image scanner
In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...
s and many other common devices with Wi-Fi in addition to other connections, like USB.
The widespread adoption of Wi-Fi in new classes of smaller devices has made the need for working ad hoc networking much more important. Even without a central Wi-Fi hub/router, it would be useful for a laptop computer to be able to wirelessly connect to a local printer. Although the ad hoc mode was created to address this sort of need, the lack of additional information for discovery makes it difficult to use in practice.
Although systems like UPnP and Bonjour provide many of the needed capabilities and are included in some devices, a single widely supported standard was lacking, and support within existing devices was far from universal. A guest using their smart phone would likely be able to find a hot spot and connect to the Internet with ease, perhaps using Protected Setup to do so. But the same device would find streaming music to a computer or printing a file might be difficult, or simply not supported between differing brands of hardware.
Technical Description
Wi-Fi Direct essentially embeds a software access point, or "soft AP", into any device that wishes to support Direct. The soft AP provides a version of Wi-Fi Protected Setup with its push-button or PIN-based setup.When a device enters the range of the Wi-Fi Direct host, it can connect to it using the existing ad-hoc protocol, and then gather setup information using a Protected Setup-style transfer. Connection and setup is so simplified that some suggest it may replace Bluetooth
Bluetooth
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
in some situations.
Soft AP's can be as simple or as complex as the role requires. A digital picture frame might provide only the most basic services needed to allow digital cameras to connect and upload images. A smart phone that allows data tethering might run a more complex soft AP that adds the ability to bridge to the Internet. The standard also includes WPA2 security and features to control access within corporate networks.
Wi-Fi Direct-certified devices can connect one-to-one or one-to-many and not all connected products need to be Wi-Fi Direct-certified. One Wi-Fi Direct enabled device can connect to legacy Wi-Fi certified devices.
The Wi-Fi Direct certification program is developed and administered by the Wi-Fi Alliance
Wi-Fi Alliance
The Wi-Fi Alliance is a trade association that promotes Wireless LAN technology and certifies products if they conform to certain standards of interoperability. Not every IEEE 802.11-compliant device is submitted for certification to the Wi-Fi Alliance, sometimes because of costs associated with...
, the industry group that develops the standards suite underlying the Wi-Fi CERTIFIED certification program and owns the "Wi-Fi" trademark
Trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...
. The final specification has not been released, and certain aspects of the system have not been mentioned to date. For instance, the system used for discovery and device classification, an analogue of UPnP or Bonjour
Bonjour (software)
In computing, Bonjour is Apple Inc.'s trade name for its implementation of Zeroconf, a group of technologies that includes service discovery, address assignment, and name resolution...
, has not been mentioned in existing references.
The first Wi-Fi Direct certified smart phone was the Samsung Galaxy S (GT-I9000). (Nov 2010)
Commercialization
Intel's My WiFi solution provides the Wi-Fi Direct technology on the Centrino 2 CPU. Wi-Fi Direct devices can connect to a notebook computer that plays the role of a Soft AP. The notebook computer can then provide Internet access to the Wi-Fi Direct-enabled devices without a Wi-Fi AP. Atheros, Broadcom, Intel, Ralink and Realtek announced their first products in October, 2010. Redpine SignalsRedpine Signals
Redpine Signals is a fabless semiconductor and wireless-systems company with chipset and system level products for wireless networks. Founded in 2001, it is headquartered in San Jose, CA with a development center in Hyderabad, India...
' chipset is Wi-Fi Direct certified in November,2010. Google announced Wi-fi Direct support in Android 4.0 in October, 2011. While some Android 2.3 devices have had this feature through proprietary operating system extensions developed by OEMs, the Galaxy Nexus
Galaxy Nexus
The Galaxy Nexus is a touchscreen slate Android smartphone developed by a partnership between Samsung and Google. The phone and operating system were developed collaboratively by engineers from both companies. It is the third generation successor to Google’s previous flagship phones, the Nexus One...
was the first Android device to ship with Google's implementation of this feature and an API for developers to use for application development.