TransferJet Technology Tutorial
- TransferJet close proximity wireless transfer technology for simple connection and transfer of data.
TransferJet technology tutorial includes:• TransferJet basics • Physical layer • Connection layer, CNL • Protocol layer • Antenna / coupler
TransferJet is a form of close proximity wireless transfer technology.
TransferJet operates by touching (or bringing very close together) two enabled devices whereupon high speed wireless data transfer can be performed.
The concept of TransferJet consists of a touch-activated interface to enable high-speed wireless data transfer between two devices in a peer-to-peer mode.
The wireless data transfer interface means that there is no requirement for connectors, and this makes the interface easier to use and more reliable than wired connections.
TransferJet is a contactless high speed data exchange interface that uses wireless connectivity to provide high speed data transfer / exchanges between two devices.The specification states that it combines the speed of UWB with the ease of operation of NFC to deliver data throughput speeds of 560Mbps (375 Mbps actual throughput with error correction) by simply touching the two devices together.
The aim is that TransferJet can be used for file interchanges between mobile phones, cameras, camcorders, televisions, games consoles, computers, and any other electronic data device.
The aim is that all the data transfers can be made simply by touching devices together, although in some instances the selection of the required file or files to be transferred may be needed. In this way file transfers can be made simply, reliably and effectively.
To promote and standardise the concept for TransferJet, a Consortium was established in 2008 by a group of international companies. The aim of the TransferJet Consortium was to develop and promote the technology, products and services. It also developed the specification for the system as well as compliance testing, processes and tools for the technology.
The consortium is based in Japan where it was registered on 1st September 2011 and has a growing lsit of member companies.
TransferJet is a short range wireless technology that uses the near field effect for communications. It uses a direct sequence spread spectrum, DSSS, transmission modulated onto the carrier using Π/2 BPSK. The chip rate of 560cps means that the signal centred on 4.48 GHz is spread over a bandwidth of 560 MHz. This gives it a very low power spectral density of less than -70dBm/MHz which is more than adequate for the few centimetres range required.
The choice of spectrum and low power transmitted mean that unlicensed operation is possible in Japan, Europe, the US as well as many other regulatory domains.
TransferJet utilises a robust protocol which incorporates error detection and correction, packet acknowledgement, and packet resend. These reduce the effects of any interference that may be experienced to enable reliable communications of the data. The system also operates on a peer-to-peer, 1 to 1 network topology, making communications much more straightforward.
The low power not only means that regulatory issues are minimised, but it also helps to minimize power consumption. As a further measure, TransferJet devices can detect the presence of other similar devices that come within range. This means that transmissions are only made when another device is in range.
TransferJet Specification Summary
|TransfetJet Specification Summary|
|Transmission power||Below -70dBm / MHz|
|Transmission rate|| 560 Mbps before error correction
375 Mbps effective throughput
|Connection distance||Up to a few centimetres|
|Network topology||1 to 1|
|Antenna||Electric induction field coupler|
|RF modulation||Direct sequence spread spectrum with Π/2 BPSK|
|Carrier frequency||4.48 GHz centre frequency|
|Signal bandwidth||560 MHz|
By Ian Poole
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