6G Faces Implementation Challenges Including Satellite/Terrestrial Spectrum Overlap

6G poses a variety of practical engineering challenges that need addressing, from aggregation of numerous spectrum bands to integration of satellite coverage into terrestrial wireless networks, Mingxi Fan, communications systems design general manager at Taiwanese semiconductor maker MediaTek, said Thursday at the Brooklyn 6G Summit. Also a question mark is timing of 3rd Generation Partnership Project work on 6G, said Wanshi Chen, 3GPP Technical Specification Group RAN1 chairman.

There's a danger of overlap between satellite bands like Ku and 6G use of the terrestrial upper mid band, Fan said. That is going to require interference mitigation steps across terrestrial and nonterrestrial networks, he said. On-earth beam footprint stabilization also will be needed to allow more-seamless handover and coordination between those networks, he said.

As more bands are used, the peak-to-average power ratio in 6G devices will become problematic, and optimizing their power use will be a challenge, Fan said. Still to be answered is what meaningful experience 6G will bring compared with 5G, he said. "We don't have the answer today," he said.

For now, 3GPP is largely focused on 5G-advanced, with the forthcoming Release 18 marking the first 5G-advanced standards, Chen said. The package of Release 19 projects will be finalized in December, with the work on the standards beginning in early 2024, he said. Like other 3GPP releases, it should take about 18 months to complete, he said. Release 19's primary goal is meeting commercial deployment needs, while also serving as a bridge to 6G, he said. Interest is strong in Release 19 covering such areas as channel modeling for new spectrum, such as 7-24 GHz, and integrated communications and sensing, he said. Release 18, meanwhile, is covering areas ranging from advanced duplexing and extended reality to drones and expanded satellite communications, he said.

The timing of 3GPP work on 6G, including when the first 3GPP 6G workshop should happen and when the first 3GPP release for 6G would be done, is still to be determined, he said. Chen said a brief 3GPP 6G discussion in September looked at 6G timelines, with more talk and possible decisions coming next month.

Some 6G Summit speakers discussed likely 6G use cases. An array of fully autonomous farm equipment, from tractors to fertilizer spreaders and planters, is available today for agriculture, but they need connectivity, said Ben Craker, portfolio manager at AgGateway. Onur Altintas, senior executive engineer-Toyota North American R&D, said vehicular communications is “still at 1G, the first-generation stage.” He said essentially no vehicle-to-everything communications is available in the U.S., it’s far more penetrated in Japan and used for such services as first-responder and oncoming vehicle warnings and adaptive cruise control. He said 6G could bring vehicular integration with non-terrestrial networks. Moving from 5G to 6G isn’t necessarily going to create a new world of verticals but allows evolution of use cases and scaling them up globally, said Meryem Simsek, head of Nokia Bell Labs’ Network Architecture Research Laboratory.