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Flexible Spectrum Orchestration of Carrier Aggregation for 5G-Advanced

Xianghui Han, Chunli Liang, Ruiqi Liu, Xingguang Wei, Mengzhu Chen, Yu-Ngok Ruyue Li, Shi Jin

TL;DR

The paper analyzes flexible spectrum orchestration for 5G-Advanced carrier aggregation by decoupling DL/UL carrier associations across bands and introducing UL-only SCells to support UL-heavy and spectrum-scarce scenarios. It details an Enhanced CA framework, cell configuration strategies, and requirements for SCell without SSB to save energy, and presents Release 18 techniques such as Multi-Cell scheduling, UL Tx switching, and energy-saving CA with evaluative results. MC scheduling reduces PDCCH signaling and supports up to four jointly scheduled cells, UL Tx switching across up to four bands yields around 24% gains in UE throughput, and SSB-less SCell approaches can achieve up to ~22% network energy savings. Overall, the work demonstrates practical gains in spectral efficiency and energy efficiency, guiding standardization and deployment of flexible CA in 5G-Advanced.

Abstract

With increasing availability of spectrum in the market due to new spectrum allocation and re-farming bands from previous cellular generation networks, a more flexible, efficient and green usage of the spectrum becomes an important topic in 5G-Advanced. In this article, we provide an overview on the 3rd Generation Partnership Project (3GPP) work on flexible spectrum orchestration for carrier aggregation (CA). The configuration settings, requirements and potential specification impacts are analyzed. Some involved Release 18 techniques, such as multi-cell scheduling, transmitter switching and network energy saving, are also presented. Evaluation results show that clear performance gain can be achieved by these techniques.

Flexible Spectrum Orchestration of Carrier Aggregation for 5G-Advanced

TL;DR

The paper analyzes flexible spectrum orchestration for 5G-Advanced carrier aggregation by decoupling DL/UL carrier associations across bands and introducing UL-only SCells to support UL-heavy and spectrum-scarce scenarios. It details an Enhanced CA framework, cell configuration strategies, and requirements for SCell without SSB to save energy, and presents Release 18 techniques such as Multi-Cell scheduling, UL Tx switching, and energy-saving CA with evaluative results. MC scheduling reduces PDCCH signaling and supports up to four jointly scheduled cells, UL Tx switching across up to four bands yields around 24% gains in UE throughput, and SSB-less SCell approaches can achieve up to ~22% network energy savings. Overall, the work demonstrates practical gains in spectral efficiency and energy efficiency, guiding standardization and deployment of flexible CA in 5G-Advanced.

Abstract

With increasing availability of spectrum in the market due to new spectrum allocation and re-farming bands from previous cellular generation networks, a more flexible, efficient and green usage of the spectrum becomes an important topic in 5G-Advanced. In this article, we provide an overview on the 3rd Generation Partnership Project (3GPP) work on flexible spectrum orchestration for carrier aggregation (CA). The configuration settings, requirements and potential specification impacts are analyzed. Some involved Release 18 techniques, such as multi-cell scheduling, transmitter switching and network energy saving, are also presented. Evaluation results show that clear performance gain can be achieved by these techniques.
Paper Structure (15 sections, 6 figures)

This paper contains 15 sections, 6 figures.

Table of Contents

  1. Introduction
  2. Framework of flexible association of DL and UL carriers
  3. Cell Configuration and Activation for Enhanced CA Framework
  4. DL-limited Cell or UL-only Cell
  5. Requirements of SCell without SSB for inter-band CA
  6. Potential specification impacts of UL-only SCell
  7. Key techniques for flexible associated CA
  8. Multi-Cell (MC) Scheduling
  9. UL Tx Switching
  10. Energy saving schemes for CA
  11. Evaluation Results
  12. Evaluation for MC scheduling
  13. Evaluation for UL Tx switching
  14. Evaluation for network energy saving
  15. Conclusion

Figures (6)

  • Figure 1: Enhanced CA framework with flexible association of DL and UL carriers
  • Figure 2: Two examples for cell configuration and activation for the enhanced CA framework
  • Figure 3: Example of Framework #2, i.e., dynamic Tx carrier switching among two indicated bands
  • Figure 4: Gain of PDCCH blocking rate and CCE saving Vs Number of scheduled cells
  • Figure 5: UPT Performance for UL Tx Switching with 4 bands
  • ...and 1 more figures