Tech-invite3GPPspecsSIPRFCs
Overview21222324252627282931323334353637384‑5x

Content for  TS 38.300  Word version:  16.3.0

Top   Top   Up   Prev   Next
1…   4…   4.7…   5…   5.3…   5.4…   6…   6.2…   6.6…   7…   8…   9…   9.2.2…   9.2.3…   9.2.3.2   9.2.3.3…   9.2.4…   9.2.6…   9.3…   10…   11…   15…   15.5…   16…   16.3   16.4…   17…   A…   B…

 

6  Layer 2Word‑p. 39

6.1  Overview

The layer 2 of NR is split into the following sublayers: Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP) and Service Data Adaptation Protocol (SDAP). The two figures below depict the Layer 2 architecture for downlink and uplink, where:
  • The physical layer offers to the MAC sublayer transport channels;
  • The MAC sublayer offers to the RLC sublayer logical channels;
  • The RLC sublayer offers to the PDCP sublayer RLC channels;
  • The PDCP sublayer offers to the SDAP sublayer radio bearers;
  • The SDAP sublayer offers to 5GC QoS flows;
  • Comp. refers to header compression and segm. to segmentation;
  • Control channels (BCCH, PCCH are not depicted for clarity).
Reproduction of 3GPP TS 38.300, Figure 6.1-1: Downlink Layer 2 Structure
Up
Reproduction of 3GPP TS 38.300, Figure 6.1-2: Uplink Layer 2 Structure
Up
Radio bearers are categorized into two groups: data radio bearers (DRB) for user plane data and signalling radio bearers (SRB) for control plane data.
For IAB, the Layer 2 of NR also includes: Backhaul Adaptation Protocol (BAP).
  • The BAP sublayer supports routing across the IAB topology and traffic mapping to BH RLC channels for enforcement of traffic prioritization and QoS.
Figure 6.1-3 below depicts the Layer-2 architecture for downlink on the IAB-donor. Figures 6.1-4 and 6.1-5 depict the Layer-2 architecture for downlink and uplink on the IAB-node, where the BAP sublayer offers routing functionality and mapping to BH RLC channels.
Reproduction of 3GPP TS 38.300, Figure 6.1-3: DL L2-structure for user plane at IAB-donor
Up
Reproduction of 3GPP TS 38.300, Figure 6.1-4: DL L2-structure at IAB-node
Up
Reproduction of 3GPP TS 38.300, Figure 6.1-5: UL L2-structure at IAB-node
Up

Up   Top   ToC