Scell Dormancy Signaling via Pcell DCI for Faster NR Transitions

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Solution Overview

Problem

Existing wireless communication standards lack defined signaling for transitioning secondary cells (Scells) between dormancy-like and non-dormancy-like behavior, leading to inefficiencies in bandwidth part transitions.

Innovation Solution

Implementing OSI layer 1 (L1) signaling on a primary cell (Pcell) to indicate transitions to and from a dormant state for secondary cells (Scells), utilizing bitfields in DCI formats to efficiently manage Scell dormancy based on numerology and BWP configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If L1 signaling is implemented for Scell dormancy indication, then transition efficiency and bandwidth management are improved, but signaling complexity and protocol overhead increase

Engineering Contradiction:
ImproveScell transition efficiencyVSAvoidsignaling complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the Scell dormancy indication function into existing L1 signaling structures (DCI formats and MAC CE commands) rather than creating a separate signaling mechanism. This integration allows efficient Scell state transitions while utilizing already-deployed signaling infrastructure, thereby improving transition efficiency without proportionally increasing overall signaling complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent makes existing L1 signaling structures multi-functional by enabling them to carry both traditional scheduling information and Scell dormancy indication bits. This universal approach allows the same signaling mechanisms to serve multiple purposes (resource allocation and dormancy control), improving productivity while avoiding the need for dedicated complexity-increasing signaling channels

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of time

If dedicated DCI bits are added for dormancy indication, then Scell activation latency is reduced, but DCI format complexity increases

Engineering Contradiction:
Improveactivation latencyVSAvoidDCI format complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies partial action by adding only the minimum necessary bits (1-2 bits) to DCI formats for dormancy indication, rather than redefining entire DCI structures. This selective addition achieves the goal of reducing activation latency while keeping the increase in DCI format complexity minimal and manageable

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the parameter structure of existing DCI formats by introducing new bit fields for dormancy indication while maintaining the overall DCI framework. This parameter-level modification allows latency reduction through faster state transition signaling without fundamentally altering DCI complexity, as the changes are confined to specific fields rather than the entire format

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple Scell groups are monitored for dormancy, then bandwidth management flexibility is improved, but processing overhead increases

Engineering Contradiction:
Improvebandwidth management flexibilityVSAvoidprocessing overhead
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments Scells into multiple groups and applies dormancy indication separately to each group using bitmaps. This segmentation enables flexible bandwidth management by allowing independent control of different Scell groups, while the bitmap representation keeps processing overhead manageable through compact data structures that efficiently encode group-level dormancy states

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4055949B1L1 signaling for scell dormancy indication
Publication Date: 2025.12.31 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4055949B1 patent drawingFigure 1
  • EP4055949B1 patent drawingFigure 2
  • EP4055949B1 patent drawingFigure 3

AI summary

A method, system and apparatus are disclosed. According to one or more embodiments, a wireless device (22) configured to communicate with a network node(16) is provided. The wireless device (22) includes processing circuitry (84) configured to: receive downlink control information, DCI, from a primary cell, Pcell; determine that at least one bitfield in the DCI indicates a secondary cell Scell, dormancy; and cause the wireless device (22) to transition the Scell from one of to and from a dormant state based on the at least one bitfield, a timing of the transition being based on a numerology of at least one of the Pcell and Scell.