R1-2601876
discussion
6G general aspects and frameworks
From Ericsson
Summary
Ericsson's Tdoc R1-2601876 provides 31 proposals and 8 observations across 8 main sections, covering spectrum aggregation, MRSS/IoT coexistence, channel bandwidth, duplexing, coverage, and UCI transmission for 6G. The document emphasizes lessons learned from 5G NR to reduce complexity.
Position
Ericsson proposes enhanced carrier aggregation (CA) as the primary 6G spectrum aggregation tool, requiring means for fast/instant activation, same-configuration indications, multi-carrier single-DCI scheduling, and removing tight time-synchronous dependencies like DAI. They require deprioritizing gNB dynamic SBFD, gNB FD, and UE SBFD in the duplexing study, proposing removal of SFI-based (DCI 2_0) operation for dynamic TDD and introducing new 'Mixed DL/UL' and 'None' frame resource types. They propose aligning 5G/6G RB boundaries and enabling dynamic CORESET sharing for MRSS, while defining a virtual carrier ('Gothia cell') only if it solves problems not addressable by CA enhancements. They propose specific coverage requirement values (e.g., 1 Mbps DL / 30 kbps UL at MaxCL 143 dB) and strive for time-asynchronous UCI reporting with L2-based MAC CE transmission and multi-bit contention-based scheduling requests.
Key proposals
- Proposal 1 (Sec 2.1): Support means to quickly activate data transmission on additional carriers, leveraging solutions developed in later 5G releases as well as on-demand SSB transmissions.
- Proposal 6 (Sec 2.2): Support uplink-downlink decoupling as part of the enhanced carrier-aggregation framework.
- Proposal 7 (Sec 2.3): Revisit the need for a PCell/SCell split in 6G. RLF should be declared only if all carriers have failed.
- Proposal 8 (Sec 2.4): For the purpose of RAN1 discussion, a virtual carrier ('Gothia cell') is defined by [specific properties a-e listed in the document].
- Proposal 10 (Sec 2.5): With time-asynchronous UCI reporting, CA can handle scenarios for non-collocated nodes.
- Proposal 11 (Sec 3.1): Resource block boundaries are aligned between 5G and 6G on an MRSS carrier.
- Proposal 13 (Sec 3.2): Coexistence between 6GR and eMTC can be achieved using semi-statically configured resource reservation with at least RB-level and symbol-level resolution (FFS: RE-level resolution).
- Proposal 16 (Sec 4): Support frequency-domain resource allocations up to 1100 resource blocks on a carrier.
- Proposal 17 (Sec 4.1): Before concluding on the smallest maximum UE bandwidth, await the outcome of the RAN4 study of the feasibility of efficient half-duplex UE Tx implementation.
- Proposal 19 (Sec 5.1): For Dynamic TDD, the key lesson learned is the high complexity of SFI operation using DCI 2_0. Remove SFI-based operation from the 6G duplexing study.
- Proposal 22 (Sec 5.1): Any new duplexing schemes for 6G should be studied in a holistic manner and must demonstrate clear, measurable performance gains with reasonable complexity compared to other already standardized solutions/technologies before being adopted.
- Proposal 24 (Sec 5.3): For 6GR, study frame format configurations incorporating a 'Mixed DL/UL' resource type that natively supports flexible time-frequency configurations, enabling both traditional duplexing modes, dynamic TDD, and advanced duplexing modes such as SBFD.
- Proposal 27 (Sec 6.2): RAN1 provides the following input to RAN#112. For the overall coverage requirement in Section 5.1.20 of TR 38.914 consider the following values that are currently marked as TBD: [specific table of data rates and parameters].
- Proposal 28 (Sec 7.2): Strive for a more time-asynchronous UCI reporting mechanism.
- Proposal 31 (Sec 7.2): Study multi-bit contention-based reports as an alternative to dedicated single-bit scheduling requests.