Tablet Growth Boosts Wireless Data Traffic by 200% per Year
The burgeoning growth of smartphones and tablet devices has seen wireless data traffic volumes grow at a rate of nearly 200% per year. Testing is already underway throughout the world on next-generation 5G mobile data systems designed to deliver speeds of up to 10 Gbps (around 1,000 times faster than existing technology) with a view to making 5G available by 2020.
Fujitsu has developed a multi-access system using multiplexing technology in the millimeter wave band to harness the wide bandwidth spectrum. This system supports the simultaneous transmission of large volumes of data by multiple users with minimal loss of speed.
5G Multiplexing Millimeter-Wave Beam System Delivers a World-Record Transmission Speed of 12 Gbps
Conventional technology does not support simultaneous transmission. Instead, transmission intervals and frequencies are partitioned to prevent interference, but this compromises transmission speed. The Fujitsu prototype system uses an antenna array with multiple elements to achieve a five-fold reduction in extraneous signal components generated during beam formation in the 60 GHz millimeter-wave band.
Narrow radio beam multiplexing allows multiple users to send data simultaneously without interference problems and with minimal drop in transmission speeds for very large data volumes. In-house testing of four millimeter-wave beams successfully demonstrated world-record speeds of up to 12 Gbps.
Multiple Antenna Arrays Prevent Interference and Support Simultaneous Transmission
Conventional antennas encounter beam interference when deployed in multiple locations and therefore are not able to be configured as an array.
The Fujitsu prototype consists of a 64-patch antenna array that forms a narrow 60 GHz millimeter-wave beam with a minimum of side lobes* (see above). An antenna array operating at a standard power density will generally exhibit a power differential of 13 dB between the main and side lobes.* By modifying the antenna power supply circuit to distribute most power to antenna elements near the center and progressively less power to elements further away from the center, Fujitsu was able to boost the power differential between the main and side lobes to around 20 dB, an improvement of 7 dB or 80%.
The exact configuration of the antenna array, with each antenna facing in a slightly different direction, allows multiple simultaneous transmissions with negligible interference.
* The main lobe is the radio signal in the intended direction; side lobes are signal components in other directions.
Fujitsu has developed an interference-free transmission system capable of world-record speeds of up to 12 Gbps that supports multiple data-rich transmissions from a single location with minimal impact on speed. This breakthrough has significant implications for the future of high-resolution video downloading and uploading to the cloud.
Fujitsu Laboratories continues to pursue technical enhancements to millimeter-wave transmitters, particularly in relation to transmission speed and power consumption relative to bit rate, with a view to their commercialization by 2020.