3GPP sharetechnote
https://www.sharetechnote.com/html/5G/5G_Mib_Sib.html
8.6.2 Downlink NAS Transport (https://www.tech-invite.com/3m38/toc/tinv-3gpp-38-413_j.html#e-8-6-2)
Identity Request（https://www.eventhelix.com/5G/standalone-access-registration/details/5g-standalone-access-registration.html#identity-request）
1. In RRC_IDLE there are DRX measurement requirements as described by 3GPP TS 38.133 4.2.2.2 for UE, to monitor the cell on which it has completed UE Attach.
2. If the cell broadcasts SSB-MTC (AKA smtc) configuration in SIB2 the UE may use them to improve power saving in RRC_IDLE, by respective configuration of DRX cycle in RRC_IDLE
3. Configuration broadcasted originally by RSYS (according SIB2 configuration in CU), was not matching the radio broadcasts on the cell, for the case there are not many IDLE/active UEs – which is our lab case- single UE
4. Quectel module based on Qualcomm platform is following strictly optimized power saving plan, and aligned its measurement plan in RRC_IDLE to broadcasted smtc information.
5. As a result, the empty (“zero energy”) slots are considered in measurement and the cell gets over time classified as too low RX_level, RX_qual criteria to fulfill cell selection criteria (as soon as UE gets to RRC_IDLE state after initial UE Attach)
6. This causes cell reselection, and results in modem reboots.
7. Solution is to align smtc content to PCCH broadcast schedule configured on the cell
8. Problem can get masked by “quick fingers” – if PDCP context is established quickly enough after UE Attach. This way UE moves to RRC_CONNECTED state, and uses different DRX scheme and the cell is considered suitable for continuation of PDCP context.
5G NR Measurement – Serving Cell and Neighbor Cell
5G NR: Measurement Configuration - How LTE Stuff Works?
https://www.3gpp.org › tsg_ran › Inbox › Drafts
5GNR: Measurement and Reporting configuration
