3 Definitions, symbols and abbreviations
37.3403GPPMulti-connectivityNROverall descriptionRelease 17Stage 2TS
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1] and TS 36.300 [2].
Child node: IAB-DU’s or IAB-donor-DU’s next hop neighbour IAB-node.
Conditional PSCell Addition: a PSCell addition procedure that is executed only when PSCell addition execution condition is met.
Conditional PSCell Change: a PSCell change procedure that is executed only when PSCell change execution condition is met.
En-gNB: node providing NR user plane and control plane protocol terminations towards the UE, and acting as Secondary Node in EN-DC.
Fast MCG link recovery: in MR-DC, an RRC procedure where the UE sends an MCG Failure Information message to the MN via the SCG upon the detection of a radio link failure on the MCG.
IAB-donor: gNB that provides network access to UEs via a network of backhaul and access links.
IAB-MT: IAB-node function that terminates the Uu interface to the parent node using the procedures and behaviours specified for UEs unless stated otherwise.
IAB-node: RAN node that supports NR access links to UEs and NR backhaul links to parent nodes and child nodes. The IAB-node does not support backhauling via E-UTRA.
Master Cell Group: in MR-DC, a group of serving cells associated with the Master Node, comprising of the SpCell (PCell) and optionally one or more SCells.
Master node: in MR-DC, the radio access node that provides the control plane connection to the core network. It may be a Master eNB (in EN-DC), a Master ng-eNB (in NGEN-DC) or a Master gNB (in NR-DC and NE-DC).
MCG bearer: in MR-DC, a radio bearer with an RLC bearer (or two RLC bearers, in case of CA packet duplication in an E-UTRAN cell group, or up to four RLC bearers in case of CA packet duplication in a NR cell group) only in the MCG.
MN terminated bearer: in MR-DC, a radio bearer for which PDCP is located in the MN.
MCG SRB: in MR-DC, a direct SRB between the MN and the UE.
Multi-Radio Dual Connectivity: Dual Connectivity between E-UTRA and NR nodes, or between two NR nodes.
Ng-eNB: as defined in TS 38.300 [3].
NR sidelink communication: AS functionality enabling at least V2X Communication as defined in TS 23.287 [18], between two or more nearby UEs, using NR technology but not traversing any network node.
Parent node: IAB-MT’s next hop neighbour node; the parent node can be IAB-node or IAB-donor-DU.
PCell: SpCell of a master cell group.
PSCell: SpCell of a secondary cell group.
RLC bearer: RLC and MAC logical channel configuration of a radio bearer in one cell group.
Secondary Cell Group: in MR-DC, a group of serving cells associated with the Secondary Node, comprising of the SpCell (PSCell) and optionally one or more SCells.
Secondary node: in MR-DC, the radio access node, with no control plane connection to the core network, providing additional resources to the UE. It may be an en-gNB (in EN-DC), a Secondary ng-eNB (in NE-DC) or a Secondary gNB (in NR-DC and NGEN-DC).
SCG bearer: in MR-DC, a radio bearer with an RLC bearer (or two RLC bearers, in case of CA packet duplication in an E-UTRAN cell group, or up to four RLC bearers in case of CA packet duplication in a NR cell group) only in the SCG.
SN terminated bearer: in MR-DC, a radio bearer for which PDCP is located in the SN.
SpCell: primary cell of a master or secondary cell group.
SRB3: in EN-DC, NGEN-DC and NR-DC, a direct SRB between the SN and the UE.
Split bearer: in MR-DC, a radio bearer with RLC bearers both in MCG and SCG.
Split PDU Session (or PDU Session split): a PDU Session whose QoS Flows are served by more than one SDAP entities in the NG-RAN.
Split SRB: in MR-DC, a SRB between the MN and the UE with RLC bearers both in MCG and SCG.
User plane resource configuration: in MR-DC with 5GC, encompasses radio network resources and radio access resources related to either one or more PDU sessions, one or more QoS flows, one or more DRBs, or any combination thereof.
V2X sidelink communication: AS functionality enabling V2X Communication as defined in TS 23.285 [19], between nearby UEs, using E-UTRA technology but not traversing any network node.
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 [1] and TS 36.300 [2].
BFD Beam Failure Detection
CHO Conditional Handover
CLI Cross Link Interference
CPA Conditional PSCell Addition
CPAC Conditional PSCell Addition or Change
CPC Conditional PSCell Change
DAPS Dual Active Protocol Stack
DC Intra-E-UTRA Dual Connectivity
DCP DCI with CRC scrambled by PS-RNTI
EN-DC E-UTRA-NR Dual Connectivity
IAB Integrated Access and Backhaul
MCG Master Cell Group
MN Master Node
MR-DC Multi-Radio Dual Connectivity
NE-DC NR-E-UTRA Dual Connectivity
NGEN-DC NG-RAN E-UTRA-NR Dual Connectivity
NR-DC NR-NR Dual Connectivity
RLM Radio Link Monitoring
SCG Secondary Cell Group
SMTC SS/PBCH block Measurement Timing Configuration
SN Secondary Node
V2X Vehicle-to-Everything