R1-2600053
discussion
6G Bandwidth Operation
From FUTUREWEI
Summary
This Futurewei contribution analyzes 5G NR Bandwidth Part (BWP) operation lessons and proposes a framework for 6GR bandwidth operation supporting multi-carrier cells with multiple simultaneous active BWPs. The document contains 3 Observations and 11 Proposals.
Position
Futurewei proposes allowing a single 6GR cell to map to multiple component carriers to handle fragmented irregular spectrum, preserving the 5G NR BWP definition as a contiguous spectrum part within a carrier. They propose UE operation with more than one active BWP simultaneously in a multi-carrier cell, introducing intra-cell CA with one PCC/PBWP for control/RS/RRC connectivity and one or more SBWPs for data exchange. They require the PBWP to remain active during SBWP activation/deactivation to minimize disruptions and transition latency. They propose studying two HARQ solutions for multiple active BWPs: single TB transmission over multiple active BWPs with one HARQ process per TB, versus one TB transmission per active BWP with one HARQ process per BWP. They propose improving BWP DCI-based switching reliability via two-stage DCI or MAC CE, and studying BWP association with QoS for improved performance.
Key proposals
- Observation 1 (Sec 5G BWP Operation): A cell is associated with a service area and has a unique identity carried by the synchronization signals, and cell global identifier.
- Observation 2 (Sec Bandwidth Part Operation for 6GR): Fragmented, irregular spectrum allocations can potentially increase substantially 6GR design complexity.
- Proposal 1 (Sec Bandwidth Part Operation for 6GR): In 6GR support that a cell may have multiple component carriers to cope with fragmented irregular spectrum.
- Observation 3 (Sec Bandwidth Part Operation for 6GR): In 5G NR when CA is configured and one or multiple SCell activated, a UE operates simultaneously in multiple active BWP.
- Proposal 2 (Sec Bandwidth Part Operation for 6GR): In 6GR reuse the BWP definition as a contiguous spectrum part within a carrier.
- Proposal 3 (Sec Bandwidth Part Operation for 6GR): In 6GR support UE operation with more than one active BWP simultaneously in a multi-carrier cell.
- Proposal 4 (Sec Bandwidth Part Operation for 6GR): For a cell with more than one carrier, there is a single carrier used as the initial access carrier where the CD-SSB and SIB1 are broadcast, and the corresponding BWP is defined as the Initial DL BWP.
- Proposal 5 (Sec Bandwidth Part Operation for 6GR): The Initial DL BWP may be used to monitor paging, and LP WUS.
- Proposal 6 (Sec Bandwidth Part Operation for 6GR): Intra-cell CA supports one PCC and its corresponding PBWP used by default for transmitting and monitoring controls and reference signals and maintaining the RRC connectivity with upper layers. In addition to the PBWP one or more SBWPs are used for data exchange.
- Proposal 7 (Sec Bandwidth Part Operation for 6GR): 6GR BWP should have a simpler design and configuration across multiple BWPs while reducing interruptions.
- Proposal 8 (Sec Bandwidth Part Operation for 6GR): 6GR should improve reliability of BWP DCI based switching, for instance using two stage DCI or MAC CE.
- Proposal 9 (Sec Bandwidth Part Operation for 6GR): In one cell with multiple active BWP(s) study and compare One TB transmission over multiple active BWP (single HARQ process per TB over multiple active BWPs) and One TB transmission in each active BWP (one HARQ process per TB over one active BWP).
- Proposal 10 (Sec Bandwidth Part Operation for 6GR): Support maintaining the PBWP active during activation and deactivation of additional SBWPs, to minimize disruptions and transition latency.
- Proposal 11 (Sec Bandwidth Part Operation for 6GR): Study whether BWP association with QoS could lead to improved performance.