5G Random Access Beam Selection for Faster RACH Handover

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Solution Overview

Problem

In 5G wireless communication systems, the selection of suitable synchronization signal blocks for random access channel (RACH) preambles is challenging, particularly in scenarios involving beamforming, re-transmissions, and handovers, leading to inefficiencies and increased latency.

Innovation Solution

A method for a UE to select synchronization signal blocks based on signal quality thresholds and network indications, using mechanisms such as system information, RRC signaling, and handover commands to optimize RACH preamble and resource selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If beamforming techniques are used to mitigate propagation loss and increase transmission distance, then transmission reliability is improved, but device complexity increases due to the need for multiple antennas and beam management

Engineering Contradiction:
Improvetransmission reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the beamforming process into discrete beam pairs (downlink beam and uplink beam) that can be independently selected and managed. Each beam pair is associated with specific RACH resources, allowing the system to divide the complex beamforming task into manageable segments that can be handled through standardized procedures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by having the network pre-configure multiple downlink beams and associate them with corresponding uplink beams and RACH resources before the actual random access procedure. This allows the UE to select from pre-established beam pairs without requiring complex real-time beamforming calculations during the access process.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple RACH resources are configured for different beam pairs to improve access reliability, then connection reliability is improved, but device complexity increases due to additional resource management

Engineering Contradiction:
Improveconnection reliabilityVSAvoidresource management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a universal mapping relationship where each downlink beam is associated with a specific uplink beam and corresponding RACH resources. This multi-functional association allows the same RACH resource configuration to serve multiple purposes: beam identification, uplink synchronization, and random access contention resolution, thereby managing complexity through standardized universal procedures.

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

Solution Approach 2:

The patent implements feedback mechanisms where the network monitors the random access responses from multiple UEs and can adjust beam associations and RACH resource allocations based on observed performance. This feedback loop allows the system to optimize connection reliability while managing resource complexity through data-driven adjustments rather than static complex configurations.

Inventive Principle:
Principle #23Feedback

3Reliability

If the UE selects the best downlink beam for RACH transmission to improve access success rate, then access reliability is improved, but measurement and selection time increases

Engineering Contradiction:
Improveaccess success rateVSAvoidbeam selection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the network pre-configure and signal multiple downlink beam configurations to the UE before the random access procedure begins. The UE can then select from these pre-evaluated beams based on simple criteria (such as reference signal received power) rather than performing complex real-time measurements on all possible beams, significantly reducing selection time while maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by having the UE focus measurements and selections on locally relevant beams - specifically, beams that are spatially aligned with the UE's position and have been pre-identified by the network as suitable for that location. This localized approach reduces the search space and measurement time compared to evaluating all system-wide beams.

Inventive Principle:
Principle #3Local quality

4Length of stationary object

If beamforming is implemented in 5G systems to support higher frequency bands, then transmission distance is improved, but system complexity increases due to advanced antenna techniques

Engineering Contradiction:
Improvetransmission distanceVSAvoidsystem complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent segments the beamforming implementation into discrete, manageable components: downlink beam configurations, uplink beam associations, and RACH resource mappings. Each component can be independently configured and optimized, allowing the system to achieve long transmission distances through coordinated simple actions rather than monolithic complex processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces RACH resources as an intermediary that bridges the downlink beam selection and uplink transmission. The RACH resources carry beam identification information and enable the UE to indicate its selected beam without requiring direct complex beamforming control between the UE and network, simplifying the overall system architecture while maintaining transmission distance capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4336903B1Method and apparatus for performing random access procedure
Publication Date: 2026.04.22 SAMSUNG ELECTRONICS CO LTD
  • EP4336903B1 patent drawingFigure 1~2
  • EP4336903B1 patent drawingFigure 3
  • EP4336903B1 patent drawingFigure 4

AI summary

A communication method and system for converging a fifth generation (5G) communication system for supporting higher data rates beyond a fourth generation (4G) system with a technology for internet of things (IoT) are provided. The communication method and system includes intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services.