Radio Link Control

In Release 15, specific corrections and clarifications were introduced for the RLC function, including a correction on the Sequence Number (SN) size for RLC Acknowledged Mode and a clarification on the RLC Unacknowledged Mode SN size for NB-IoT. Furthermore, the release introduced a procedure for reporting RLC failures and addressed the association of PDCP with RLC for radio bearers configured with PDCP duplication.

• Introduction of New Radio Access Technology in TS 36.300 TS 36.300CR0998
• Control Plane latency reduction TS 36.306CR1614
• EN-DC impacts to LTE RLC TS 36.322CR0132
• Control Plane latency reduction TS 36.331CR3453
• Introduction of support for MAC PDU containing UE contention resolution identity MAC control element without RRC response message in NB-IoT TS 36.306CR1570
• Correction on SN size for RLC AM TS 36.322CR0141

+ 27 more changes

In Release 16, the RLC function was enhanced to support new deployment scenarios, including the introduction of a Backhaul (BH) RLC Channel for Integrated Access and Backhaul (IAB) nodes and corrections to support the BAP as an upper layer. It also introduced specific handling for transmission suspension on BH RLC channels upon IAB-MT failure and clarified procedures for RLC out-of-order delivery configuration. Furthermore, security risks for RLC AM and UM bearers during termination point changes were addressed, and RLC re-establishment procedures upon RRC resume/reestablishment were defined.

• UE radio access capabilities introduction for IIOT WI (CR for 36.306) TS 36.306CR1758
• Introducing UE Radio Capability Mapping procedure for EN-DC TS 36.300CR1314
• Incorrect restriction for RLC UM radio bearers TS 36.331CR4385
• Addition of total L2 buffer size and RLC RTT for NR SL TS 38.306CR0547
• Correction on RLC spec to support the BAP as upper layer TS 38.322CR0036
• CR to 38.322 on Backhaul RLC Channel TS 38.322CR0037

+ 14 more changes

In Release 17, the RLC function saw specific corrections and clarifications, primarily focused on sidelink relay operation and bearer configuration. The changes included corrections for establishing the receiving RLC entity for SL-SRB0 and SL-SRB1, as well as a clarification on RLC bearer re-association procedures. These updates provided necessary refinements to support sidelink relay functionality and ensure correct RLC entity handling.

• Correction on PDCP Control PDU for UDC feedback TS 36.323CR0304
• Correction on RLC for SL relay TS 38.322CR0048
• RLC correction for SL relay TS 38.322CR0050
• Correction on PDCP Control PDU for UDC feedback TS 38.323CR0105
• Corrections to control plane procedures for RedCap UEs TS 38.331CR3780
• Channel Access Control for msg1/msgA in FR2-2 TS 38.331CR3827

+ 7 more changes

In Release 18, the RLC (Radio Link Control) layer was enhanced to support new functionalities like Network-Controlled Repeaters and multi-path relay, requiring specific corrections for RLC handling in these scenarios. The release also introduced updates for sidelink (PC5) communication, including corrections to RLC channel handling and release procedures. Furthermore, RLC was adapted to work with the unified Transmission Configuration Indicator (TCI) state framework, necessitating corrections for power control parameters and interactions with PDCP, such as the delay critical indication.

• Introduction of Rel-18 network-controlled repeaters TS 38.201CR0004
• Introduction of Network Controlled Repeaters in RRC spec TS 38.331CR4162
• RLC correction for multi-path relay with N3C TS 38.322CR0063
• Data volume calculation for DSR when associated with at least two RLC entities TS 38.323CR0133
• Correction for Delay Critical Indication from PDCP to RLC TS 38.323CR0144
• Miscellaneous RRC corrections for Network-controlled repeaters TS 38.331CR4617

+ 10 more changes

In Release 19, the RLC (Radio Link Control) function was enhanced to support Extended Reality (XR) traffic, with the specification receiving dedicated corrections and updates for these R19 XR enhancements. The release also included corrections for the PC5 Relay RLC channel configuration. No changes related to positioning parameters or power control, as indicated in some titles, were made to the RLC layer itself, as those pertain to other protocol layers.

• Introduction of control parameters for on-demand posSIB request [OdPosSIB_Req] TS 38.306CR1323
• Introduction of R19 XR enhancements for RLC spec. TS 38.322CR0065
• Introduction of control parameters for on-demand posSIB request [OdPosSIB_Req] TS 38.331CR5406
• Miscellaneous corrections on RLC for R19 XR TS 38.322CR0066
• Miscellaneous corrections on RLC for R19 XR TS 38.322CR0067
• Correction on PC5 Relay RLC channel configuration TS 38.331CR5510

+ 2 more changes