6G migration splits the industry three ways, and the choice slips to RAN#114

The baseline is not in dispute: 6G launches standalone, shares existing 5G spectrum through multi-RAT spectrum sharing (MRSS), and hands phones over between 5G and 6G. The fight is over what gets added. A coalition of 14 companies — Samsung, Qualcomm and 12 operators including NTT DOCOMO, SK Telecom, Verizon, BT and Deutsche Telekom — wants exactly one addition: dual connectivity in which a standalone 6G base station is the anchor and an existing 5G carrier is added for throughput. AT&T, Intel, NEC, MediaTek and Vodafone lean the same way, AT&T and MediaTek only as the single extra option. The idea is not new: 5G standards defined the equivalent arrangement with 5G as the anchor and LTE added (NE-DC), and operators rarely deployed it.

Nokia and Ericsson reject every dual-connectivity and dual-stack variant. Nokia argues that 5G's many non-standalone and dual-connectivity options fragmented the market and slowed the uptake of native 5G features, and it asked for three mechanisms to be struck from the study: dual stack or dual registration, 5G-anchored and 6G-anchored dual connectivity. ZTE rejects a 5G anchor and accepts a 6G anchor only with strong justification. A third group — CMCC, CATT, vivo, Orange and the satellite players Boost Mobile, AST SpaceMobile, Skylo and EchoStar — wants the phone registered to the 5G and 6G cores at once, mainly to keep voice working while 6G coverage is patchy. The 5G-anchored variant, the model early 5G used with LTE, found only conditional backing: Orange and Vodafone keep it as a fallback. Huawei wanted the whole decision pushed to March 2027.

The plenary postponed the choice to RAN#114, where it will also decide whether options 1 and 2 would use a split bearer, carrying one data flow over both radio links. It kept a simplified form of Option 3, the core-network route, on the table: no aggregation in the core, no traffic split and no impact on the radio network — just two ordinary single registrations, to the 5G core and the 6G core, aimed at 5G voice (VoNR) on the 5G leg and 6G data on the 6G leg. The core-network architects were asked to confirm by RAN#114 that this works, and the 3GPP systems plenary will make the final call. Separately, 6G must be able to share at least downlink control-channel resources efficiently with 5G when both run in the same spectrum.

On combining spectrum from base stations at different sites, the plenary asked the radio-protocol experts to study further — within the existing 6G study — how to aggregate a sub-7 GHz (FR1) and a millimetre-wave (FR2) carrier over backhaul with up to 10 milliseconds of delay. The study assumes two independent schedulers, one per site, the arrangement 5G dual connectivity already uses. Physical-layer studies had found that both dual connectivity with two cell groups and carrier aggregation with two groups of uplink control channels (PUCCH) and separate timing advance could work, and Nokia's simulations favoured carrier aggregation; neither has been chosen. A coalition of Verizon, Apple, Qualcomm, Samsung and 11 others got a multi-vendor interoperable solution written in as the goal, so an operator can still combine base stations from different suppliers.

In the core-network study, 3GPP's architects approved text adding a 'priority group' to 6G device policies. A 5G phone must try network-provided routes strictly in precedence order; with priority groups the network can mark several routes as equivalent and let the phone choose among them using local preferences such as a power-saving mode, falling back to strict order when it has none. The text updates one candidate solution in the 6G architecture study report and is co-signed by Samsung, Nokia, Huawei and HiSilicon. It is not yet a 6G feature: how the priority group is defined and managed is still marked for further study, and competing candidate solutions remain in the report.

The 6G requirements report already sets two coverage targets: 'basic coverage' at a maximum coupling loss of 143 dB with 1 Mbps downlink, and 'extended coverage' that tolerates 10 dB more path loss, at 153 dB, with 100 kbps downlink and 2 kbps uplink. For comparison, NB-IoT was designed for 164 dB. Lenovo proposed writing in how the extended target would be reached — relaxing control-channel reliability from a 1% to a 10% block error rate — but the plenary discarded that text. It also discarded MediaTek's proposal that phone-side data collection should allow vendor-specific data, and suspended text on 6G device types until the 6G radio study's own device-type discussion concludes, parking MediaTek's proposed 20 MHz minimum bandwidth for basic devices. At RAN#114 the question is narrower than the dispute suggests: 6G standalone with MRSS stays the baseline whatever happens; what is decided is whether one extra migration route joins it, and which.