Joint UL-DL Beam Correspondence for Low-Latency Beam Management

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In wireless cellular communication systems, separate uplink and downlink beam management can result in high overhead, latency, and power consumption due to the assumption of beam correspondence, which may not always be valid, especially for 5G and NR systems.

Innovation Solution

Implement methods and mechanisms for joint uplink and downlink beam management, including eNB-side and UE-side beam correspondence indications, using synchronization signals and higher-layer signaling to confirm beam correspondence, and utilizing SRS and CSI-RS for beam refinement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate uplink and downlink beam management is implemented with beam correspondence assumption, then beam management can be performed independently for each direction, but overhead, latency, and power consumption increase

Engineering Contradiction:
Improveindependent beam managementVSAvoidlatency
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent combines separate uplink and downlink beam management procedures into a joint beam management approach. The gNB configures both UL and DL beam parameters together, and the UE reports beam measurements for both directions in a unified manner, reducing the number of separate signaling exchanges and procedure steps required

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If separate uplink and downlink beam management is implemented with beam correspondence assumption, then beam management can be performed independently for each direction, but overhead and power consumption increase

Engineering Contradiction:
Improveindependent beam managementVSAvoidpower consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent merges beam management operations to reduce power consumption. By configuring UL and DL beams jointly and reporting measurements in a unified procedure, the UE and gNB reduce the total number of active processing events, signaling transmissions, and measurement operations that consume power

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If beam correspondence is assumed, then beam management is simplified, but reliability decreases when correspondence does not hold

Engineering Contradiction:
Improvebeam management complexityVSAvoidbeam correspondence validity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic beam management where the gNB and UE can adapt between correspondence-based and non-correspondence-based approaches. The system dynamically configures beam parameters based on actual channel conditions and reciprocity validity, allowing flexibility to switch strategies rather than being fixed to one approach

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates feedback mechanisms where the UE reports beam measurements and quality indicators for both UL and DL. This feedback allows the gNB to verify whether beam correspondence holds in practice and adjust beam configurations accordingly, ensuring reliability even when initial assumptions are incorrect

Inventive Principle:
Principle #23Feedback

4Loss of time

If joint uplink and downlink beam management is implemented, then latency and power consumption are reduced, but system complexity increases

Engineering Contradiction:
ImprovelatencyVSAvoidbeam management system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent creates universal beam management procedures that handle both correspondence-based and non-correspondence-based scenarios through unified configuration and reporting mechanisms. The same basic procedure structure serves multiple operational modes, reducing the need for separate specialized procedures for each case

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

Data Source

PatentEP3536101B1Beam reciprocity indication and joint uplink downlink beam management
Publication Date: 2025.11.19 APPLE INC
  • EP3536101B1 patent drawingFigure 1
  • EP3536101B1 patent drawingFigure 2
  • EP3536101B1 patent drawingFigure 3

AI summary

Described is a User Equipment (UE). The User Equipment (UE) is operable to communicate with an Evolved Node-B (eNB) on a wireless network and comprises one or more processors to: process a first transmission carrying an indicator of eNB beam correspondence; and generate a second transmission carrying an indicator of UE beam correspondence; and an interface for receiving the first transmission and for sending the second transmission.