Nokia · 10.6.2

Nokia proposes that the UL WUS signal type should reuse existing uplink signals: PRACH preamble for RRC Idle/Inactive UEs and existing uplink signals/channels (SRS, UL DMRS, SR, PUCCH, PUSCH) for RRC Connected UEs. They argue against a dedicated low-power BS receiver module for UL WUS, stating none is foreseen for 6G BS hardware, and require that the UL WUS signal utilize the common radio modem to minimize operational cost. Nokia questions the feasibility of DS#1a due to the unresolved issue of UL WUS transmit power determination without DL pathloss estimation from PSS/SSS, and requires confirmation from spectrum regulations on whether a UE can transmit without first receiving DL synchronization signals. They propose studying a UL WUS framework that allows UEs to conditionally reuse stored system information to avoid redundant MIB/SIB1 acquisition, and support studying on-demand reference signals triggered by UL WUS for SCell operations and cell switch mobility.

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.