SAN JOSE, Calif. – Cohere Technologies wants its wireless coding scheme to be adopted as part of the 5G air interface being defined over the next year. To make its case, the startup released today data from a field trial that one analyst called promising.
Cohere’s Orthogonal Time Frequency and Space (OTFS) uses time and frequency data to characterize wireless channels. Backers claim the approach is more precise than today’s methods, reducing signal fading and reflections and yielding benefits in coverage and bandwidth.
OTFS is said to be particularly valuable for 5G which is widely expected to use dozens of antennas to hit new peak data rates in urban areas. It also helps cope with the Doppler Effect on wireless transmissions which is especially useful given the goal of making 5G available on fast moving trains. And it is suitable for use in existing cellular frequency bands as well as anticipated new millimeter-wave bands.
“We solved some very fundamental problems around imperfect channel information and timing references that the wireless community has been struggling with forever,” said Shlomo Rakib, a serial entrepreneur and Cohere’s chief executive. “The good news is this is a thin layer above OFDM-based cellular silicon today, requiring small transforms in the modulation process that should require less than 10% in addition to today’s silicon,” he added.
Cohere's field tests show its technology significantly outperforming today's LTE. (All images: Cohere)
In trials using 2x2 and 4x4 MIMO antenna arrays and FPGA boards, Cohere’s approach carried signals up to four kilometers. The tests, conducted with an unnamed wireless carrier, maintained a minimum of 4 bits/second/Hz in 10MHz achieving data rates of 120-320 Mbits/second.
The tests were held in urban settings with tall buildings, mountainous regions, rural settings and in moving vehicles with and without line-of-site configurations. Cohere claims its approach can support links for mobile users moving at up to 500 kilometers/hour.
“Our overhead to acquire a channel is 0.15% per stream – much, much lower than today 5-7% to acquire a stream,” Rakib said.
To date, Cohere has filed about 50 patents on its technology and has 12 granted. It has raised nearly $90 million in venture funding, most of it from a recently closed C round led by Telstra.
Next page: Catching the 5G air interface
Cohere claims its approach can maintain connections even a 500 km/hour.