Dynamic 2-Step to 4-Step Random Access Switching

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Solution Overview

Problem

In NR-based wireless communication systems, the 2-step random access procedure is inefficient due to the need to transmit a payload alongside the preamble, leading to communication failures based on radio quality, necessitating a fallback to the 4-step procedure to ensure successful synchronization and scheduling requests.

Innovation Solution

A terminal and communication system that dynamically switches between 2-step and 4-step random access procedures based on predetermined triggers, such as radio quality degradation or high-priority processes, allowing for efficient fallback and transition between the two procedures to ensure successful random access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the 2-step random access procedure is used, then the random access completion time is reduced, but the communication reliability deteriorates due to payload transmission requirements

Engineering Contradiction:
Improverandom access completion timeVSAvoidcommunication reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent implements dynamic switching between 2-step and 4-step random access procedures based on radio quality conditions. When radio quality is good, the system uses the faster 2-step procedure; when radio quality degrades, it switches to the more reliable 4-step procedure. This dynamic adaptation resolves the contradiction by allowing the system to optimize for speed when possible and for reliability when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the random access procedure type as a parameter based on radio quality measurements. By monitoring radio quality and adjusting the procedure selection accordingly, the system can achieve both fast access when conditions permit and reliable access when conditions deteriorate, resolving the time-reliability tradeoff.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the 2-step random access procedure is used, then the procedure speed is improved, but the ease of operation deteriorates due to additional payload transmission requirements

Engineering Contradiction:
Improveprocedure speedVSAvoidease of operation
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The system dynamically selects between 2-step and 4-step procedures based on operational conditions. When radio quality is sufficient, it operates in the simplified 2-step mode for speed. When conditions worsen, it transitions to the more robust 4-step mode, automatically adapting to maintain ease of operation while preserving speed when possible.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs self-assessment of radio quality and autonomously decides which random access procedure to use. This self-service capability allows the system to automatically handle the complexity of procedure selection without requiring manual intervention, maintaining ease of operation while optimizing for procedure speed.

Inventive Principle:
Principle #25Self-service

3Reliability

If the 4-step random access procedure is used, then the communication reliability is improved, but the loss of time increases compared to the 2-step procedure

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidrandom access completion time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system dynamically adapts between 4-step and 2-step procedures based on radio quality. When reliability is the primary concern or radio quality is poor, it uses the reliable 4-step procedure. When radio quality is good and speed is prioritized, it switches to the faster 2-step procedure, thus resolving the time-reliability contradiction through conditional operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the random access procedure parameter based on radio quality thresholds. By setting appropriate thresholds and dynamically adjusting the procedure type, the system minimizes time loss while maintaining sufficient reliability, achieving an optimal balance between these two parameters.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3920636B1Terminal, communication system and communication method
Publication Date: 2024.11.13 NTT DOCOMO INC
  • EP3920636B1 patent drawingFigure 1
  • EP3920636B1 patent drawingFigure 2
  • EP3920636B1 patent drawingFigure 3

AI summary

A user equipment includes a transmitting unit configured to transmit signals required for a first random access procedure and a second random access procedure, a receiving unit configured to receive signals required for the first random access procedure and the second random access procedure, and a control unit configured to switch the first random access procedure and the second random access procedure according to a predetermined switch trigger, wherein when the control unit switches the first random access procedure and the second random access procedure, the control unit indicates, in an after-the-switching random access procedure, information related to a prior-to-the-switching random access procedure to a base station apparatus.