Random Access Resource Switching in 5G Bandwidth Parts

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Solution Overview

Problem

Current 5G New Radio (NR) technology faces challenges in optimizing random access procedures, particularly in determining available random access resources within bandwidth parts, which affects the efficiency and latency of user equipment (UE) communication with base stations.

Innovation Solution

The method involves a UE receiving a request to initiate a random access procedure and determining whether the active bandwidth part contains available random access resources. If not, the UE switches to another bandwidth part with available resources and transmits a preamble sequence at a selected random access resource, ensuring a specific time duration subsequent to the request, while if resources are available in the first part, the UE transmits the sequence at a shorter time duration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE waits for random access resources in the current active bandwidth part, then resource availability is maintained, but access latency increases

Engineering Contradiction:
Improverandom access resource availabilityVSAvoidaccess latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic bandwidth part switching based on real-time random access resource availability. The UE monitors the active bandwidth part for available random access resources and dynamically switches to a different bandwidth part when resources are unavailable, thereby reducing access latency while maintaining reliable resource availability through adaptive resource selection across multiple bandwidth parts.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the UE switches bandwidth parts to find available random access resources, then access efficiency improves, but device complexity increases

Engineering Contradiction:
Improverandom access efficiencyVSAvoidbandwidth part management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring multiple bandwidth parts with their respective random access resources before the actual random access procedure. The UE is provided with information about available random access resources in different bandwidth parts in advance, allowing it to quickly determine and switch to an appropriate bandwidth part without complex real-time resource discovery, thus improving access efficiency while managing device complexity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3735801B1RACH timeline
Publication Date: 2022.05.11 MEDIATEK INC
  • EP3735801B1 patent drawingFigure 1
  • EP3735801B1 patent drawingFigure 2
  • EP3735801B1 patent drawingFigure 3

AI summary

A UE receives a request from a base station to initiate a random access procedure in a connected state. When a first bandwidth part does not contain any random access resource that is available, the UE: switches to a second bandwidth part that contains one or more random access resources that are available and transmits a preamble sequence at a first random access resource selected from the one or more random access resources that are available. When the first bandwidth part contains the one or more random access resources that are available, the UE transmits the preamble sequence at a second random access resource selected from the one or more random access resources that are available. The second random access resource is at least a second time duration subsequent to the request. The second time duration is shorter than the first time duration.