3 Definitions, symbols and abbreviations

36.3223GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Radio Link Control (RLC) protocol specificationRelease 15TS

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].

byte segment: A byte of the Data field of an AMD PDU. Specifically, byte segment number 0 corresponds to the first byte of the Data field of an AMD PDU.

Data field element: An RLC SDU or an RLC SDU segment that is mapped to the Data field.

NB-IoT: NB-IoT allows access to network services via E-UTRA with a channel bandwidth limited to 200 kHz.

NB-IoT UE: A UE that uses NB-IoT.

RLC SDU segment: A segment of an RLC SDU.

Sidelink communication: AS functionality enabling ProSe Direct Communication as defined in TS 23.303 [7], between two or more nearby UEs, using E-UTRA technology but not traversing any network node. In this version, the terminology "sidelink communication" without "V2X" prefix only concerns PS unless specifically stated otherwise.

3.2 Abbreviations

For the purposes of the present document, the following abbreviations apply:

AM Acknowledged Mode


ARQ Automatic Repeat reQuest

BCCH Broadcast Control CHannel

BCH Broadcast CHannel

BR-BCCH Bandwidth Reduced Broadcast Control CHannel

CCCH Common Control CHannel

DCCH Dedicated Control CHannel

DL DownLink

DL-SCH DL-Shared CHannel

DTCH Dedicated Traffic CHannel

E Extension bit


E-UTRA Evolved UMTS Terrestrial Radio Access

E-UTRAN Evolved UMTS Terrestrial Radio Access Network

FI Framing Info


LI Length Indicator

LSF Last Segment Flag

MAC Medium Access Control

MCCH Multicast Control Channel

MTCH Multicast Traffic Channel

NB-IoT NarrowBand Internet of Things

PCCH Paging Control CHannel

PDU Protocol Data Unit

PS Public Safety

RLC Radio Link Control

RRC Radio Resource Control

SAP Service Access Point

SBCCH Sidelink Broadcast Control Channel

SC-MCCH Single Cell Multicast Control Channel

SC-MTCH Single Cell Multicast Transport Channel

SDU Service Data Unit

SN Sequence Number

SO Segment Offset

STCH Sidelink Traffic Channel

TB Transport Block

TM Transparent Mode


UE User Equipment

UL UpLink

UM Unacknowledged Mode


V2X Vehicle-to-Everything