R1-2600047
discussion
On Uplink WUS and corresponding operation
From Nokia
Summary
This Nokia contribution presents 3 Observations and 2 Proposals regarding 6G uplink Wake-Up Signal (WUS) design. Nokia argues that PRACH/RACH procedure study (A.I. 10.5.1.2) should be prioritized before UL WUS (A.I. 10.6.2), as current understanding is insufficient to differentiate UL WUS from PRACH or identify its unique benefits. They further propose that any future UL WUS signal type should be identical to other uplink signals to enable common BS radio modem reception and minimize network operational cost.
Position
Nokia proposes postponing the UL WUS and operation study on A.I. 10.6.2 to avoid duplication with the foundational PRACH and RACH procedure study on A.I. 10.5.1.2. They present a technical case that the current stage lacks clarity on what key complements UL WUS signal provides over PRACH preamble design, whether sufficient performance gain exists in coverage or energy efficiency to justify the extra design effort, and what use cases UL WUS operation covers that RACH procedure cannot. For the feasibility aspect, Nokia opposes dedicated low-power radio (LPR) receiver architecture for UL WUS at the base station, instead requiring that the UL WUS signal type be identical to other uplink signals so that common network hardware and the common radio modem at the BS side can be reused with functionalities implemented simply by a subset of existing hardware components.
Key proposals
- Proposal 1 (Sec 2): To avoid duplicated/overlapping study and design, it is proposed to postpone the discussions on the 6GR study of uplink WUS and operation on A.I. 10.6.2.
- Proposal 2 (Sec 3): The UL WUS signal shall be the same signal type as the other uplink signals, benefiting and making feasible the utilization of common radio modem at BS side for uplink reception.
- Observation 1 (Sec 2): For 6GR design in uplink, PRACH signal and its related procedure are one of the study items on A.I. 10.5.1.2 in parallel with the study of uplink WUS and operation.
- Observation 2 (Sec 2): Compared with the study of uplink WUS and operation, the PRACH preamble and its related procedure are the fundamental design for 6GR network operation that shall be thoroughly investigated and studied first.
- Observation 3 (Sec 2): It is hard to clarify the key differences between UL WUS signal and PRACH preamble, the key complements of UL WUS signal to PRACH preamble design, and the key differences of UL WUS operation from the RACH procedure; details can only be identified after study of PRACH and RACH procedure on A.I. 10.5.1.2 are fully exploited.