Content for TR 38.874 Word version: 16.0.0
2 References
3 Definitions and abbreviations
4 Introduction
5 Requirements
6 Architectures
7 Physical layer aspects
8 Radio protocol aspects
9 Backhaul aspects
10 Comparison
11 Conclusion
A Evaluation methodology
$ Change History
2 References
3 Definitions and abbreviations
4 Introduction Word‑p. 8
5 Requirements
5.1 Use cases and deployment scenarios
5.1.1 Relay deployment scenarios
5.1.2 In-band vs. out-of-band backhaul Word‑p. 9
5.1.3 Access/backhaul RAT options
5.1.4 Standalone and non-standalone deployments
5.2 Architecture Requirements Word‑p. 10
6 Architectures
6.1 General
6.2 IAB Architectures proposed Word‑p. 13
6.3 Architecture group 1 Word‑p. 14
6.3.1 Architecture 1a
6.3.2 Architecture 1b Word‑p. 15
6.4 Architecture group 2
7 Physical layer aspects
7.1 General
7.2 Backhaul link discovery and measurements
7.2.1 IAB-node initial access (Stage 1)
7.2.2 Inter-IAB-node discovery and measurement (Stage 2) Word‑p. 18
7.2.3 IAB-node RACH
7.2.4 Backhaul link management
7.3 Scheduling and resource allocation/coordination Word‑p. 19
7.3.1 Scheduling of backhaul and access links
7.3.2 Multiplexing of access and backhaul links
7.3.3 Resource coordination Word‑p. 21
7.4 IAB-node synchronization and timing alignment Word‑p. 23
7.5 Cross-link interference measurement and management Word‑p. 25
7.6 Spectral efficiency enhancements
7.7 Summary of Physical Layer Enhancements for IAB
8 Radio protocol aspects Word‑p. 26
8.1 Packet Processing
8.2 User-plane considerations for architecture group 1
8.2.1 General
8.2.2 Adaptation Layer Word‑p. 28
8.2.3 Multi-hop RLC ARQ Word‑p. 30
8.2.4 Scheduler and QoS impacts Word‑p. 32
8.2.4.1 UE-bearer-to-BH-RLC-Channel mapping
8.2.4.2 Enforcement of Fairness Schemes Word‑p. 33
8.2.4.3 Radio aware scheduling Word‑p. 35
8.2.5 L2 structure Word‑p. 36
8.2.6 Flow control and congestion handling Word‑p. 39
8.2.7 UP support of IAB-node Word‑p. 41
8.2.8 Security protection of F1*-U Word‑p. 43
8.2.9 Unified design for architecture group 1 Word‑p. 44
8.2.10 Examples of unified design for architecture group 1
8.2.10.1 Design Example 1 Word‑p. 45
8.2.10.2 Design Example 2 Word‑p. 47
8.3 Control-plane considerations for architecture group 1 Word‑p. 50
8.3.1 Routing and QoS enforcement for CP signaling
8.3.2 CP signaling protocols Word‑p. 51
8.3.3 Control plane transport requirements
8.3.4 CP signaling security protection
8.3.5 CP alternatives for architecture 1a
8.3.6 Control Signalling to BH-RLC-Channel mapping for architecture 1a Word‑p. 57
8.3.7 CP alternatives for architecture 1b Word‑p. 59
8.4 User-plane considerations for architecture group 2 Word‑p. 60
8.5 Control-plane considerations for architecture group 2 Word‑p. 61
8.6 Latency in UL scheduling
9 Backhaul aspects Word‑p. 64
9.1 Additional Interfaces
9.2 IAB Topologies
9.3 Integration of IAB-node Word‑p. 67
9.4 Modifications to CU/DU architecture Word‑p. 72
9.5 Backhaul bearer setup for architecture group 1
9.6 IAB Topology Discovery Word‑p. 74
9.6.1 Discovery procedure for architecture group 1
9.6.2 Discovery procedure for architecture group 2 Word‑p. 75
9.7 Topology adaptation Word‑p. 76
9.7.1 Goals of IAB topology adaptation
9.7.2 Tasks pertaining to IAB topology adaptation
9.7.3 Topologies considered for architecture 1a
9.7.4 Topology adaptation scenarios in architecture 1a Word‑p. 77
9.7.5 Principal steps of intra-CU topology adaptation in architecture 1a Word‑p. 79
9.7.6 Principal steps of inter-CU topology adaptation in architecture 1a Word‑p. 82
9.7.7 Detailed steps of topology adaptation in architecture 1a Word‑p. 86
9.7.8 Goals of Topological Redundancy
9.7.9 Adding redundant routes in architecture 1a Word‑p. 87
9.7.10 Detailed steps of route addition in architecture 1a Word‑p. 89
9.7.11 Route Management Word‑p. 90
9.7.12 Backhaul-link-failure recovery scenarios Word‑p. 91
9.7.13 Principal steps of BH RLF recovery in architecture 1a Word‑p. 92
9.7.14 Downstream notification of BH RLF in architecture 1a Word‑p. 97
9.7.15 Efficient backhaul-link-failure recovery Word‑p. 98
9.8 LTE-access over NR backhaul
10 Comparison Word‑p. 99
10.1 Comparison of IAB architectures
10.2 Comparison of CP alternatives for IAB architectures 1a Word‑p. 101
11 Conclusion Word‑p. 103
A Evaluation methodology Word‑p. 104
A.1 Evaluation assumptions
A.2 Evaluation results Word‑p. 109
$ Change History Word‑p. 111
