TransferJet

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TransferJet is a new type of close proximity wireless transfer technology developed by Sony and 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.

Modulation Direct Sequence Spread Spectrum (DSSS)

π/2-shifted BPSK

Connection Distance A few cm (nominal)
Connection Topology 1-to-1, Point-to-Point
Antenna Element Longitudinal electric induction coupler

Although sometimes confused with Near Field Communication, TransferJet depends on an entirely different technology and is also generally 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] Other recent products combine TransferJet with wireless power to allow both data transfer and wireless charging capability simultaneously in the same location.[5] TransferJet, NFC and wireless power are the three major near-field (contact-less) technologies that are expected to eliminate the physical connections and cables currently required to interface devices with each other.

Comparison with NFC

Technology TransferJet NFC
Center Frequency 4.48 GHz 13.56 MHz
Transmission Rate 560 Mbit/s 424 kbit/s
Main Use Cases Fast file transfer, data synchronization

audio/video streaming

Authentication, Authorization,

Electronic Payment, ID Tagging

Topology Point-to-Point(1:1), bi-directional

symmetrical

Point-to-Point(1:1), bi-directional
Connection Type (power) active-active active-passive or active-active
Connection Distance A few cm A few cm
Antenna Element Longitudinal electric induction coupler Magnetic induction coil or loop
Standardization Body ECMA 398, ISO/IEC 17568 ECMA 340, ISO/IEC 18092

The TransferJet Consortium[6] 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. In September 2011, the consortium was registered as an independent non-profit industry association. As of July 1, 2012, the Consortium is led by nine Promoter companies, consisting of: Hitachi Ltd, JVC-Kenwood, Nikon, Olympus, Panasonic, Pioneer, Seiko Epson, Sony (consortium administrator), and Toshiba.[7] The Consortium currently also has more than thirty Adopter companies, for a total of over fifty member companies.

Commercial products have been introduced since January 2010 and the initial product categories include digital cameras,[8] laptop PCs,[9] USB cradle accessories[10] and new office/business equipment.[11] Compliance testing equipment is provided by Agilent technologies and certification services are offered by Allion Test Labs and XXCAL Japan.

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