AUSTIN, Texas — Mobile operators stripped away the marketing bluster and discussed some of the real-world struggles they uncovered when conducting their 5G trials. For AT&T, foliage and obstacles blocking antennas proved to be a challenge. For Canada’s Shaw Communications, the need for better backhaul capacity quickly became evident. And for China Mobile, achieving vendor equipment interoperability was a top priority.

At the 5G New Horizons Symposium here this week carriers gathered from around the globe to compare notes on their 5G experiences.  Here’s a rundown of some of the highlights:

AT&T learned firsthand some of the challenges with using millimeter wave (mmWave) spectrum in 28 GHz and 39 GHz bands. The higher band spectrum is good for providing a lot of capacity, but it can typically only transmit a short distance and the radio signal is less capable of penetrating obstructions.

The company has been conducting several 5G trials using mmWave spectrum in cities around the country. According to Dave Wolter, AVP radio technology and strategy at AT&T Labs, environment plays a key role in the success of a 5G deployment. The company had to be very careful about where it put its antennas because things like foliage and glass coating on windows impacted the signal. AT&T also found that it could take advantage of signal reflections – in other words a signal might bounce off an object and extend the coverage area.

For Shaw Communications, the 5G journey is just beginning. The cable operator was thrust into the wireless world when it purchased Wind Mobile in 2016. Wind had about 940,000 customers but was operating a 3G network, and Shaw had to upgrade it to LTE. According to Brian O’Shaughnessy, SVP and CTO of converged networks at Shaw, the company just finished its first 5G trial last week in Calgary, Alberta. The trial used 28 GHz and 3.5 GHz spectrum and was done in conjunction with CableLabs, Nokia, and test equipment maker Rohde and Schwarz.

O’Shaughnessy said that the company used the 5G Technical Forum specification, which is the same pre-standard 5G spec currently being used by Verizon for its fixed wireless deployment.

In terms of speed, Shaw found that at about 100 meters from the antenna, using line of sight (LOS), it was able to achieve data speeds of 1.1 Gb/s to 1.5 Gb/s. With non-line of site (NLOS) at 100 meters, speeds dropped dramatically to 400 Mb/s to 500 Mb/s.

O’Shaughnessy said the company also learned that it will likely want to incorporate its 100,000 WiFi hotspots into the 5G network and move certain network functions closer to the edge so that it can improve its backhaul capacity. However, since Shaw is also a cable company, O’Shaughnessy said that it will likely leverage its cable network for the additional backhaul capacity and also to provide compute functions at the network edge.

China Mobile is in the midst of expanding its 5G trials that it is conducting in five cities. The operator initially started the trials last year with only a handful of base stations but is now increasing the number of base stations to more than 100 in each city. The trials are using equipment from multiple vendors including Ericsson, Nokia, Huawei, and ZTE.

Chih-Lin I, chief scientist at China Mobile, said that one goal of the trial is to make sure that equipment from different vendors is interoperable and that 5G can be successfully deployed using multi-vendor gear.

In July, the operator plans to have 100 cell sites deployed, and by October it hopes to have 300 cell sites deployed.

China Mobile will deploy 5G in the 3.5 GHz band, but Chih-Lin I said that it will also use mmWave spectrum later in its deployment schedule. She noted that China Mobile is closely watching U.S. operators like AT&T and Verizon that are using mmWave spectrum for their early 5G deployments. “The U.S. is probably the leader in mmWave,” she said. “Hopefully we can learn from them. But we are concerned about the cost and performance of mmWave band components.”

Editor's note:  This article was updated to include the additional detail that Shaw's 5G trial included 3.5 GHz spectrum.