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TR 38.858
Study on evolution of NR duplex operation

V18.0.0 (Wzip)2023/12  578 p.
China Mobile Com. Corporation

full Table of Contents for  TR 38.858  Word version:  18.0.0

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1  Scopep. 14

The present document captures the results and findings from the study item "Study on Evolution of NR Duplex Operation " [2]. The purpose of this TR is to document the follows for evolution of NR duplex operation:
  • applicable and relevant deployment scenarios.
  • evaluation methodology and assumptions.
  • possible schemes/enhancements, feasibility and performance evaluation results of subband non-overlapping full duplex and dynamic/flexible TDD.
  • summary of the regulatory aspects that have to be considered for deploying the identified duplex enhancements in TDD unpaired spectrum.
This activity involves the Radio Access work area of the 3GPP studies and has potential impacts both on the Mobile Equipment and Access Network of the 3GPP systems.

2  Referencesp. 14

3  Definitions of terms, symbols and abbreviationsp. 17

3.1  Termsp. 17

3.2  Symbolsp. 17

3.3  Abbreviationsp. 17

4  Introductionp. 18

TDD is widely used in commercial NR deployments. In TDD, the time domain resource is split between downlink and uplink. Allocation of a limited time duration for the uplink in TDD would result in reduced coverage, increased latency and reduced capacity. As a possible enhancement on this limitation of the conventional TDD operation, it would be worth studying the feasibility of allowing the simultaneous existence of downlink and uplink, a.k.a. full duplex, or more specifically, subband non-overlapping full duplex at the gNB side within a conventional TDD band.
The NR TDD specifications allow the dynamic/flexible allocation of downlink and uplink in time and CLI handling and RIM for NR were introduced in Rel-16. Nevertheless, further study may be required for CLI handling between the gNBs of the same or different operators to enable the dynamic/flexible TDD in commercial networks. The inter-gNB CLI may be due to either adjacent-channel CLI or co-channel-CLI, or both, depending on the deployment scenario. One of the problems not addressed in the previous releases is gNB-to-gNB CLI.
This study aims to identify the feasibility and solutions of duplex evolution in the areas outlined above to provide enhanced UL coverage, reduced latency, improved system capacity, and improved configuration flexibility for NR TDD operations in unpaired spectrum. In addition, the regulatory aspects need to be examined for deploying identified duplex enhancements in TDD unpaired spectrum considering potential constraints.

5  Objectives of studyp. 18

The objective of this study is to identify and evaluate the potential enhancements to support duplex evolution for NR TDD in unpaired spectrum.
In this study, the followings are assumed:
  • Duplex enhancement at the gNB side
  • Half duplex operation at the UE side
  • No restriction on frequency ranges
The detailed objectives are as follows:
  • Identify applicable and relevant deployment scenarios (RAN1).
  • Develop evaluation methodology for duplex enhancement (RAN1).
  • Study the subband non-overlapping full duplex and potential enhancements on dynamic/flexible TDD (RAN1, RAN4).
    • Identify possible schemes and evaluate their feasibility and performances (RAN1).
    • Study inter-gNB and inter-UE CLI handling and identify solutions to manage them (RAN1).
      • Consider intra-subband CLI and inter-subband CLI in case of the subband non-overlapping full duplex.
    • Study the performance of the identified schemes as well as the impact on legacy operation assuming their co-existence in co-channel and adjacent channels (RAN1).
    • Study the feasibility of and impact on RF requirements considering adjacent-channel co-existence with the legacy operation (RAN4).
    • Study the feasibility of and impact on RF requirements considering the self-interference, the inter-subband CLI, and the inter-operator CLI at gNB and the inter-subband CLI and inter-operator CLI at UE (RAN4).
    • Summarize the regulatory aspects that have to be considered for deploying the identified duplex enhancements in TDD unpaired spectrum (RAN4).

6  Subband non-overlapping full duplex (SBFD)p. 19

7  Performance evaluation and its feasibility for SBFDp. 27

7.1  Deployment scenariosp. 27

7.2  Evaluation methodologiesp. 28

7.3  Performance evaluation results for semi-static SBFDp. 32

7.3.1  System level simulation resultsp. 32

7.3.2  Link level evaluation resultsp. 108

7.4  Performance evaluation results of schemes for SBFDp. 112

7.4.1  Dynamic SBFDp. 112

7.4.2  Inter-gNB CLI handling schemesp. 125

7.4.3  Inter-UE CLI handling schemesp. 130

7.4.4  Inter-gNB and Inter-UE CLI handling schemesp. 134

8  Potential enhancements and analysis for dynamic/flexible TDDp. 135

8.1  Deployment scenariosp. 135

8.2  Evaluation methodologiesp. 136

8.3  Inter-gNB CLI handling schemesp. 137

8.3.1  gNB-to-gNB co-channel CLI measurement and/or channel measurementp. 137

8.3.1A  Inter-gNB CLI scheme 1A: UL Resource Muting-based scheme for measuring the gNB-to-gNB CLI interference covariance matrixp. 139

8.3.2  Coordinated scheduling for time/frequency resources between gNBsp. 144

8.3.2A  Inter-gNB CLI scheme 2A: Time domain scheme using UL slot(s) aligned between gNBsp. 144

8.3.2B  Inter-gNB CLI scheme 2B: Frequency domain coordination schemep. 146

8.3.3  Spatial domain coordination methodp. 148

8.3.3A  Inter-gNB CLI scheme 3A: Spatial domain coordination scheme for gNB Tx-Beam nullingp. 149

8.3.4  UE and gNB transmission and reception timingp. 151

8.3.5  Power control based solutionp. 151

8.3.5A  Inter-gNB CLI scheme 5A: Power control scheme based on gNB Tx power adjustmentp. 152

8.3.5B  Inter-gNB CLI scheme 5B: Power control scheme based on UE Tx power adjustmentp. 155

8.4  Inter-UE CLI handling schemesp. 159

9  Implementation feasibility of SBFDp. 162

9.1  Background for analysisp. 162

9.3  Feasibility of FR1 medium range BS aspectsp. 199

9.4  Feasibility of FR1 local area BS aspectsp. 210

9.5  Feasibility of FR2-1 BS aspectsp. 217

9.6  FR1 Feasibility of UE aspectsp. 230

9.7  FR2-1 feasibility of UE aspectsp. 233

10  Impact on RF requirementsp. 236

11  Adjacent channel co-existence evaluation resultsp. 240

12  Regulatory aspects for deploying the duplex enhancements in TDD unpaired spectrump. 245

12.1  ITU Region 1p. 245

12.1.1  Europep. 245

12.2  ITU Region 2p. 245

12.3  ITU Region 3p. 246

12.3.1  Australiap. 246

12.3.2  Chinap. 246

12.3.3  Indiap. 246

12.3.4  Japanp. 246

12.3.5  Koreap. 246

12.3.6  New Zealandp. 247

12.4  Summaryp. 247

13  Conclusions and recommendationsp. 248

A  Evaluation methodologiesp. 258

B  System level simulationp. 283

B.1  System level simulation assumptionsp. 283

B.2  System level simulation results for semi-static SBFDp. 285

B.2.1  SBFD Deployment Case 1 (FR1)p. 285

B.2.1.1  Indoor office (FR1)p. 285

B.2.1.2  Urban Macro (FR1)p. 304

B.2.1.3  Dense Urban Macro layer (FR1)p. 342

B.2.1.4  Dense Urban with 2-layer (FR1)p. 364

B.2.2  SBFD Deployment Case 1 (FR2-1)p. 367

B.2.2.1  Indoor office (FR2-1)p. 367

B.2.2.2  Dense Urban Macro layer (FR2-1)p. 382

B.2.3  SBFD Deployment Case 3-2 (FR1)p. 406

B.2.4  SBFD Deployment Case 4 (FR1)p. 421

B.3  System level simulation results of schemes for SBFDp. 489

B.4  System level simulation results for dynamic TDDp. 516

C  System level simulation calibrationp. 559

D  Link level evaluation for coverage performancep. 562

E  Adjacent channel co-existence evaluationp. 565

$  Change historyp. 578

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