TransferJet is a new type of close proximity wireless transfer technology initially demonstrated publicly in early 2008[1]. By touching (or bringing very close together) two electronic devices, TransferJet allows high speed exchange of data. The concept of TransferJet consists of a touch-activated interface which can be applied for applications requiring high-speed data transfer between two devices in a peer-to-peer mode without the need for external physical connectors[2].
TransferJet's maximum physical layer transmission rate is 560 Mbit/s. After allowing for error correction and other protocol overhead, the effective maximum throughput is 375 Mbit/s. TransferJet will adjust the data rate downward according to the wireless environment, thereby maintaining a robust link even when the surrounding wireless condition fluctuates.
TransferJet has the capability of identifying the unique MAC addresses of individual devices, enabling users to choose which devices can establish a connection. By allowing only devices inside the household, for example, one can prevent data theft from strangers while riding a crowded train. If, on the other hand, one wishes to connect the device with any other device at a party, this can be done by simply disabling the filtering function.
TransferJet uses the same frequency spectrum as UWB, but occupies only a section of this band available as a common worldwide channel. Since the RF power is kept under -70 dBm/MHz, it can operate in the same manner as that of UWB devices equipped with DAA functionality. In addition, this low power level also ensures that there will be no interference to other wireless systems, including other TransferJet systems, operating nearby.
By reducing the RF power and spatial reach down to a few centimeters (about an inch or less), a TransferJet connection in its most basic mode does not require any initial setup procedure by the user for either device, and the action of spontaneously touching one device with another will automatically trigger the data transfer. More complex usage scenarios will require various means to select the specific data to send as well as the location to store (or method to process) the received data.
TransferJet utilizes a newly developed TransferJet Coupler based on the principle of electric induction field as opposed to radiation field for conventional antennas. The functional elements of a generic TransferJet Coupler consist of a coupling electrode or plate, a resonant stub and ground. Compared to conventional radiating antennas, the TransferJet Coupler achieves higher transmission gain and more efficient coupling in the near-field while providing sharp attenuation at longer distances. Because the Coupler generates longitudinal electric fields, there is no polarization and the devices can be aligned at any angle.
TransferJet Specifications[3]
| Center Frequency | 4.48 GHz |
|---|---|
| Bandwidth | 560 MHz |
| Transmission Power | At or below -70 dBm/MHz (average)
Corresponds to low-intensity radio wave regulation in Japan and Taiwan, and with local regulations in other countries and regions. |
| Transmission Rate | 560 Mbit/s (max) / 375 Mbit/s (effective throughput)
System can adjust the transmission rate depending on the wireless environment. |
| Connection Distance | A few cm (nominal) |
| Connection Topology | 1-to-1, Point-to-Point |
| Antenna Element | Electric induction field coupler |
Although sometimes confused with Near Field Communication, TransferJet depends on an entirely different technology and is also targeted for different usage scenarios focusing on high-speed data transfer. Thus these two systems will not interfere with each other and can even co-exist in the same location, as already implemented in certain products[4].
The TransferJet Consortium[5] was established in July 2008 to advance and promote the TransferJet Format, by developing the technical specifications and compliance testing procedures as well as creating a market for TransferJet-compliant, interoperable products. As of September 2011, the Consortium is led by sixteen Promoter companies, consisting of: Canon, Casio, Hitachi Ltd, JVC-Kenwood, KDDI, Nikon, NTT docomo, Olympus, Panasonic, Pioneer, Samsung, Seiko Epson, SoftBank Mobile, Sony, Sony Ericsson and Toshiba. The Consortium currently also has thirty seven Adopter companies, for a total of fifty three member companies.
Commercial products have been introduced since January 2010 and the initial product categories include digital cameras[6], laptop PCs[7], USB cradle accessories[8] and new office/business equipment[9].
Compliance testing equipment is provided by Agilent technologies and certification services are offered by Allion Test Labs and XXCAL Japan.
(Note: TransferJet is spelled with a capital "J")