Japanese telecommunications operator NTT DoCoMo and vendor partner Huawei managed to achieve multi-gigabit speeds at a distance of more than a mile using 5G technology and millimeter (mmWave) spectrum. The demonstration could be an important step in overcoming range challenges using mmWave spectrum in support of 5G services.
The trial was conducted last month in Yokohama, Japan. It used the 39 GHz spectrum band targeted at a testing vehicle equipped with a receiver similar to a traditional mobile phone. The test showed data speeds of more than 3 Gb/s at a distance of just less than a mile and speeds of more than 2 Gb/s at just over a mile.
The companies also used beamforming technology to track the vehicle at speeds of around 15 miles per hour in delivering a stable connection.
“This successful trial result opens up a new door for applications and deployments of 5G mmWave,” the companies noted in a statement. “Long-distance mobility transmission over 5G mmWave is one of the enabling technologies to realize 5G enhanced mobile broadband (eMBB) and ubiquitous connectivity of massive data rates whilst fully leveraging the current macro-cellular site investment by operators.”
Test results were only released for the downlink, which typically provides for better coverage and performance. Uplink speeds, or the connection from a mobile device back to a transmission tower, is limited due to the inability to squeeze as much technology and power into a small, mobile device.
The trial is important in the move to use wide swaths of mmWave spectrum in support of 5G services. Carriers have spent billions of dollars on mmWave spectrum licenses that they hope to use to bolster 5G deployments.
However, those spectrum bands do not have the same reach or ability to penetrate obstacles as traditional cellular spectrum and thus limit the amount of coverage an operator can achieve from an antenna.
Roger Entner, founder and president at Recon Analytics, said the numbers provided by NTT DoCoMo and Huawei are impressive.
“It’s definitely impressive that they have been able to achieve that level of speed at nearly a mile in range,” said Entner. “And even more so since this is really just the beginning of the work on developing greater range and not the end. They might be able to get even more down the road.”
However, he did note that improving mmWave performance will be challenging. “Range and speed are related when it comes to spectrum,” Entner said. “It’s really the same physics for everyone on this.”
Verizon has been trialing mmWave spectrum in the 28 GHz and 39 GHz bands as part of its 5G plans in a handful of markets. Entner noted the carrier has been seeing speeds up to 800 Mb/s at a range of 1.2 miles.
Speaking at an investor conference earlier this year, Ronan Dunne, EVP and group president of Verizon Wireless, indicated the trials are looking at very basic issues with mmWave technology.
“Yeah, I think some of the propagation has probably been better,” Dunne said.
In its field tests, Verizon is looking at “not what’s the maximum throughput, but it’s what’s the minimum throughput in certain experiences,” Dunne said. The company is looking at propagation in certain weather conditions such as snow and heavy rain.
Dave Wolter, assistant vice president for radio technology and strategy at AT&T, said the carrier has seen more than a gigabit-per-second in speed at a distance of 250 meters using the 28 GHz band. Wolter explained that specific technologies that can be used with the 39 GHz band result in similar speeds and range to the 28 GHz band.
In terms of outright coverage, Wolter said AT&T has not yet focused on pushing the limit in its mmWave trials. The carrier has so far tested at a maximum range of around 500 meters.
“We are making some propagation measurements and will probably make adjustments as we move along,” Wolter said.