Wi-Fi Direct (Wi-Di)

From the moment of emergence of minicomputers (the CPC, smartphones) need of data exchange directly between two devices – certainly, by means of wireless communication arose. Infrared communication (IR), and the relevant port was the most primitive method began to equip all mobile devices. However, for communication devices it was necessary to locate a row, at distance of several centimeters, focusing "infra-windows" the friend opposite to the friend. Speed of communication remained very low, but also information was not volume.

Of course, such state of affairs did not suit anybody, and already shortly appeared Bluetooth – the wireless radio-frequency interface of communication working at distance up to 10 meters. Data transfer rate on it was rather high to transfer media content (including to headsets and earphones) and without problems to exchange data between the most different gadgets (notebooks, smartphones, tablets, printers, a keyboard/mouse, etc.). Bluetooth remains relevant long time: simple connection and universal distribution made it irreplaceable in the tasks.^[1]

But also it has shortcomings: the small range and low speed (to present measures) in a combination to weak security of the protocol forced developers to look for other ways. In particular, to replace it d 2013 ujle prophesied Wi-Fi Direct, or Wi-Di. This protocol is constructed based on usual Wi-Fi, but is easy-to-customizer. Its main advantages – connection speed are 12 times higher, than at Bluetooth, communication range – up to 100 meters, and, above all – good security.

From Wi-Fi it is distinguished by lack of need for a point the access/router. Of course, Wi-Fi allows connection of two devices directly (in the Ad-Hoc mode), but to configure it very not easy, and time for this purpose is required. Wi-Di is necessary only clicking of the special button on each of the connected devices – they "will agree" among themselves, will establish connection and will begin joint work. It is expected that not only notebooks, smartphones and tablets will get support of a new method of communication: it will be received also by printers, video cameras, game consoles, speaker systems, digital cameras and a set of other devices. It will allow to simplify many actions, for example, to connect a MP3 player to the speaker system, to print the photo directly from the tablet, and to send fresh pictures from the camera to a digital photoframe. Your guests will be able to show family video from the smartphone directly on the TV, and the game console will not require fuss with wires any more.

Attractively? Certainly. But "it was smooth on paper and forgot about ravines" – the technology has features which modestly hold back. The first of them – big energy consumption. In 2013 operating time of the smartphone is measured by tens of hours, and in a playback mode of a streaming video it will be reduced till several o'clock. In this case Bluetooth is immeasurably more profitable, especially with adoption of standard 4.0. The second – air "zamusorennost": provide that several home devices will begin to connect, passing access point. Inevitably there will be collisions, signal interferences that as a result will lower a data exchange rate for all devices. And if to provide the dormitory area and 30–40 neighbors with the Wi - Di - devices, then it is easy to expect absolutely uncontrollable effect on air. What will occur if several users at the same time begin "knit" devices (for example, during the celebration of New year)?

Generally, it is more questions, than answers. But one is obvious: call Wi-Fi Direct by "the murderer of Bluetooth" and designate technologies bright prospects rather early. However, in the near future we should check it in practice: analysts predict general distribution of devices with Wi-Di. In 2013 in the market there were more than 1.5 billion devices with support of Wi-fi, and to the 2015th (according to forecasts of iSuppli) their quantity will increase by one billion.

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