The CEO of Cohere Technologies highlighted demand for swift 5G deployments as a fresh opportunity to push the benefits of Massive MIMO, which has been held back by technical challenges associated with the technology.

Though companies around the globe have been experimenting with the technology, Ray Dolan told Mobile World Live the full potential of Massive MIMO has been limited by the slowness and rapid expiration of channel predictions used to direct signal beams to users.

A key technology for 5G, Massive MIMO uses multiple software-controlled transmit and receive streams to offer much higher network capacity.

But Dolan explained that with standard control methods, which rely on time and frequency measurements, it is “almost impossible” to create predictions fast enough to keep up with changes in the channel environment because those predictions are valid for such a short period of time.

He flagged the short shelf life of time and frequency predictions as a driving force behind operators’ shift to an edge architecture, since they need to be processed and acted on so quickly. This move, he said, is “reversing a decade of work that the radio guys did” to migrate functions to the cloud.

“If you have to put all of the smarts at the edge, you don’t have any visibility on what’s happening between base stations.”

Another way
Cohere Technologies is pushing an alternative which Dolan said offers more predictable channel modelling using a radar technology-inspired approach to measurement.

Rather than relying on time and frequency measurements, he explained the company’s Orthogonal Time Frequency and Space (OTFS) modulation scheme uses delay and Dopplar measurements to offer longer-lasting predictions.

He added the staying power of these predictions can give operators more flexibility in their architecture, allowing them to keep processing in the cloud and thus coordinate across base stations more efficiently.

Because the solution is so different from the status quo (that is, orthogonal frequency-division multiplexing modulation, or OFDM) and claims to offer predictions which last 1,000-times longer than today’s standard (milliseconds vs microseconds), Dolan said he expects there to be debate and “mudslinging” around whether Cohere Technologies’ system can achieve what it claims.

However, he added the company aims to push through the noise and ultimately get its set-up incorporated into industry standards.