The Wi-Fi Alliance has its origins in IEEE's committee for wireless standardization. The famous family of standards called IEEE 802.11 consist of a set of media access control and physical layer specification for the implementation in wireless communication.
Their early product suffered from interoperability problems between products from different brands due to a lack of testing equipment. From this need to have a reliable, secure and compatible wireless standard, the Wireless Ethernet Compatibility Alliance (WECA) was formed in 1999 by several companies. They branded the 802.11b technology with the name Wireless Fidelity (Wi-Fi) and provides extensive interoperability testing before products were granted the Wi-Fi certified logo.
The WECA renamed itself to its current name in 2002 and has about 600 members who can take part in the organization and take advantage of the researched technologies. It is a global non-profit industry associations consisting of their members who share the same vision of 'seamless connectivity'.
Its main product is the Wi-Fi certified logo which is a globally recognized seal of approval for Wi-Fi products. It signifies interoperability, security mechanism, backward compatibility and high quality performance. Examples of other word marks include WiGig, Miracast, WPA2 and Wi-Fi Direct.
Wi-Fi traditionally has two modes of operations: infrastructure mode for wireless communication for multiple devices connecting to an access point and ad hoc mode for peer-to-peer communication. Ad hoc mode was meant to quickly setup a local network in which each node acted as a router to forward data. This is done dynamically based on the network connectivity. Wi-Fi ad hoc mode has been proven successful in several handheld gameconsoles but had some serious limitation for other applications.
The main drawbacks of the ad hoc mode was firstly a security issue. It was shown that it provided minimal security against attackers within range. Secondly the signal strength monitoring was unavailable in this mode which makes it difficult to keep up a stable network especially when devices are not stationary. Finally the speed is limited to only 11 Mbps. Because of these limitations the Wi-Fi Alliance formed a task group to research Wi-Fi Direct, an optimized Wi-Fi version for peer-to-peer connections.
Bluetooth was originally invented by researchers from Ericsson in 1994. At that time the technology was meant to replace the RS-232 cable with a wireless standard for data communication. Today it has grown to a huge association called the Bluetooth Special Interest Group (SIG) with over 20,000 members. Since its standardization it has been an enormous success being implemented in billions of products ranging from medical equipment and cars to mobile phones and computer peripherals. It operates in the 2.4GHz band, the same as Wi-Fi, and is meant for low power operations with a maximum range of about 100 meter. Their latest implementation is Bluetooth v4.1 which includes all of the previous versions: classic Bluetooth, low power Bluetooth and Bluetooth high speed. Depending on the protocol and class it has a maximum datarate of 24Mbps.
The third major standard for short-range datacommunication is ZigBee which is standardized in 2002 by the ZigBee Alliance, an open non-profit association of members. ZigBee is based on the IEEE 802.15 standard for personal area networks (PANs) working on low energy consumption. According to their website, "ZigBee is the only standards-based wireless technology designed to address the unique needs of low-cost, low-power wireless sensor and control networks in just about any market". Their product focuses on very low power consumption and very low cost. This comes at a price considering the datarates which are limited to only 250kb/s but can have a range up to 100 meters with line-of-sight. ZigBee can be implemented as sensors which share data through each node effectively creating a mesh network without the need for centralized control.
Wi-Fi Direct is a fairly new Wi-Fi standard coming from the Wi-Fi Alliance trade association. It has been released around October 2010 and from there on, products have been Wi-Fi Direct Certified. Wi-Fi Direct is meant as a supporting technology to connect Wi-Fi compatible devices directly without the need of a wireless access point or router. As it is only a software implementation, it utilizes the existing Wi-Fi architecture and designs already available. Due to this fact it can have the same high data rates which can go up to 250Mbps.
Through Wi-Fi direct devices can make a one-to-one connection but it is also possible to connect a group of several devices simultaneously. This makes it possible to easily share data through your laptop, tablet, phone, printer, television or other Wi-Fi devices.
When setting up a connection between devices it is protected by Wi-Fi Protected Setup using their WPA2 security. Connection itself can be established by simple pressing a button, holding two devices together with near field communication or entering a PIN code. This connection is even possible without access to an internet connection as its focus is on easy sharing between devices.
