For the purposes of the present document, the terms and definitions given in
TR 21.905 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.
AM DRB:
a data radio bearer which utilizes RLC AM.
AM MRB:
an MRB associated with at least one AM RLC bearer for PTP transmission.
Broadcast MRB:
a radio bearer configured for MBS broadcast delivery.
DAPS bearer:
a bearer whose radio protocols are located in both the source gNB and the target gNB during DAPS handover to use both source gNB and target gNB resources.
Delay-critical PDCP SDU:
if pdu-SetDiscard is not configured, a PDCP SDU for which the remaining time till discardTimer expiry is less than the remainingTimeThreshold. If pdu-SetDiscard is configured, a PDCP SDU belonging to a PDU Set of which at least one PDCP SDU has the remaining time till discardTimer expiry less than the remainingTimeThreshold.
MBS Radio Bearer:
a radio bearer that is configured for MBS delivery.
Multicast MRB:
a radio bearer configured for MBS multicast delivery.
Multi-path:
Mode of operation of a remote UE in RRC_CONNECTED configured with one direct path on which the UE connects to the gNB using NR Uu and one indirect path on which the UE connects to the same gNB via another UE using PC5 unicast link or Non-3GPP Connection.
Multi-path Primary Path:
In multi-path for a split DRB, the primary path is configured by RRC to be either the direct path or the indirect path. In multi-path for a split SRB, the primary path is always the direct path.
Multi-path Secondary Path:
In multi-path for a split DRB, the path (either direct or indirect) which is not configured by RRC as the primary path. In multi-path for a split SRB, the secondary path is always the indirect path (SL or N3C).
Multi-path split bearer:
In multi-path, a bearer in which one PDCP entity is mapped to one or more (direct) Uu RLC entities and either one SRAP entity of a SL indirect path or a non-3GPP connection.
N3C indirect path:
In multi-path, the indirect path using Non-3GPP Connection between remote UE and relay UE.
Non-split bearer:
a bearer whose radio protocols are located in either the MgNB or the SgNB to use MgNB or SgNB resource, respectively.
NR sidelink communication:
AS functionality enabling at least V2X communication as defined in
TS 23.287 and ProSe communication (including ProSe non-Relay, UE-to-Network Relay, and UE-to-UE Relay communication) as defined in
TS 23.304, between two or more nearby UEs, using NR technology but not traversing any network node.
NR sidelink discovery:
AS functionality enabling ProSe non-Relay Discovery, ProSe UE-to-Network Relay discovery, and ProSe UE-to-UE Relay discovery for Proximity based Services as defined in
TS 23.304 between two or more nearby UEs, using NR technology but not traversing any network node.
NR sidelink transmission:
any NR Sidelink-based transmission, including both transmission for NR sidelink discovery and transmission for NR sidelink communication.
PDCP data volume:
the amount of data available for transmission in a PDCP entity.
PDU Set:
one or more PDUs carrying the payload of one unit of information generated at the application level (e.g. frame(s) or video slice(s) etc. for XR services), as defined in
TS 23.501. A PDU in the PDU Set corresponds to a PDCP SDU.
SL indirect path:
In multi-path, the indirect path on which the L2 U2N Remote UE connects to the network via a L2 U2N Relay UE.
Split bearer:
in dual connectivity, a bearer whose radio protocols are located in both the MgNB and the SgNB to use both MgNB and SgNB resources.
Split secondary RLC entity:
in dual connectivity, the RLC entity other than the primary RLC entity which is responsible for split bearer operation. If the PDCP entity is associated with two RLC entities, the split secondary RLC entity is the RLC entity other than the primary RLC entity. If the PDCP entity is associated with more than two RLC entities, the split secondary RLC entity is configured by upper layers.
UM DRB:
a data radio bearer which utilizes RLC UM.
UM MRB:
an MRB associated with only RLC UM.
U2N Relay UE:
A UE that provides functionality to support connectivity to the network for U2N Remote UE(s).
U2N Remote UE:
A UE that communicates with the network via a U2N Relay UE.
U2U Relay UE:
A UE that provides functionality to support connectivity between two U2U Remote UEs.
U2U Remote UE:
A UE that communicates with another UE via a U2U Relay UE.
For the purposes of the present document, the abbreviations given in
TR 21.905 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.
AM
Acknowledged Mode
ARP
Address Resolution Protocol
CID
Context Identifier
DAPS
Dual Active Protocol Stack
DRB
Data Radio Bearer carrying user plane data
EHC
Ethernet Header Compression
FIFO
First In First Out
gNB
NR Node B
HFN
Hyper Frame Number
IETF
Internet Engineering Task Force
IP
Internet Protocol
MAC
Medium Access Control
MAC-I
Message Authentication Code for Integrity
MBS
Multicast/Broadcast Services
MP
Multi-path
MRB
MBS Radio Bearer
MTCH
MBS Traffic Channel
N3C
Non-3GPP Connection
PDCP
Packet Data Convergence Protocol
PDU
Protocol Data Unit
PSI
PDU Set Importance
RB
Radio Bearer
RFC
Request For Comments
RLC
Radio Link Control
ROHC
RObust Header Compression
RRC
Radio Resource Control
RTP
Real Time Protocol
SAP
Service Access Point
SCCH
Sidelink Control Channel
SDU
Service Data Unit
SLRB
Sidelink Radio Bearer carrying NR sidelink communication or NR sidelink discovery
SN
Sequence Number
SRAP
Sidelink Relay Adaptation Protocol
SRB
Signalling Radio Bearer carrying control plane data
STCH
Sidelink Traffic Channel
TCP
Transmission Control Protocol
UDC
Uplink Data Compression
UDP
User Datagram Protocol
UE
User Equipment
UM
Unacknowledged Mode
U2N
UE-to-Network
X-MAC
Computed MAC-I