R1-2600050
discussion
6G General Aspects and Frameworks
From FUTUREWEI
Summary
This Futurewei Tdoc for the 3GPP 6G Radio study presents 18 proposals and 4 observations across multiple physical layer framework areas. The document argues for a single large maximum bandwidth option, a 2-level carrier aggregation framework (intra-cell and inter-cell CA), support for multiple carriers per serving cell, and various energy efficiency improvements in initial access design. It also addresses coverage metrics, duplex types, NTN harmonization, and SCS options for higher bands.
Position
Futurewei proposes agreeing to Opt1 for SSB design with bandwidth larger than 3MHz and selecting a single maximum bandwidth option to limit device types and maximize economies of scale. They propose redefining the serving cell concept to support multiple carriers with intra-cell CA using one PCC for control/RRC and one or more SCCs for data exchange, forming a 2-level CA framework with inter-cell CA. For 400MHz support, they propose 2x 200MHz RF chains with 2x 8k FFT and consider 1x 400MHz RF chain. They argue coverage range in meters is the most direct metric rather than a single MCL/MIL/MPL value. They propose studying SCS options for around 15GHz and supporting TDD, FDD, SBFD, and HD-FDD duplex modes from day one, while further investigating SBFD/SSFD impact on frame structure. For initial access energy efficiency, they propose transmitting MIB/SIB1 with larger periodicities than synchronization signals or on-demand, supporting on-demand SSB/SIB1, and time-adaptive/flexible scalable PRACH from Day 1.
Key proposals
- Proposal 1 (Sec 6GR Smallest maximum BW): Agree to Opt1: Design of the common signals/channels (at least for SSB) for initial access by assuming bandwidth larger than 3MHz, which is applicable to any spectrum allocations with adjustment, if applicable.
- Proposal 2 (Sec 6GR Smallest maximum BW): To limit the number of device types, minimize market fragmentation, and maximize economies of scale, a single maximum bandwidth option is selected.
- Proposal 3 (Sec 6GR One cell multiple carriers): In 6GR one serving cell may support more than one carrier.
- Proposal 5 (Sec 6GR One cell multiple carriers): Intra-cell CA supports one PCC and its corresponding BWP within the PCC where the controls are transmitted and monitored and where the RRC connectivity with upper layers is maintained and one or more BWPs each within a SCC for data exchange.
- Proposal 7 (Sec 6GR 2-Level CA): 6GR supports a 2-level carrier aggregation framework which includes intra-cell carrier aggregation and inter-cell carrier aggregation.
- Proposal 9 (Sec Support of 400 MHz channels): To support 400MHz bandwidth in 6GR, support 2x 200MHz RF chains, 2x 8k FFT with either Option 2 or Option 3 and in addition, consider supporting 1x 400 MHz RF chain with Option 1.
- Proposal 10 (Sec 6GR TN & NTN): Given 6GR MBB design, RAN1 should identify what changes of 5G NTN solutions are necessary to be considered for 6GR NTN.
- Proposal 12 (Sec 6GR Targeted Coverage): The coverage range (distance in meters) is the most direct metric for coverage analysis. One single value in MCL/MIL/MPL as a general coverage requirement may not be sufficient, though MPL may be the most direct among the three quantities.
- Proposal 13 (Sec SCS): RAN1 should identify and study the SCS options for around 15GHz.
- Proposal 14 (Sec 6GR Duplexing types): 6GR should support from day one TDD and FDD duplex modes and consider supporting from day one SBFD and HD-FDD.
- Proposal 16 (Sec 6GR Initial Access): Support transmission of MIB (PBCH) and SIB1 with larger periodicities than the synchronization signals and/or MIB (PBCH) and SIB1 per on-demand basis.
- Proposal 17 (Sec 6GR Initial Access): To improve energy efficiency during initial access consider supporting on-demand SSB, on-demand SIB1 and time adaptation of control signaling.
- Proposal 18 (Sec 6GR Initial Access): Support time adaptation and the flexible scalable design of PRACH from Day 1.