PRACH Resource Segmentation for Priority-Based Access

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Solution Overview

Problem

Current Random Access Channel (RACH) procedures in wireless communications face challenges in efficiently managing congestion and prioritizing uplink transmissions, leading to potential delays and collisions in shared PRACH resources.

Innovation Solution

Implementing methods for wireless transmit/receive units (WTRUs) to select and configure multiple sets of Physical RACH (PRACH) resources and preamble formats based on priority levels, allowing for dynamic allocation and signaling of additional PRACH resources, and handling RACH failures, thereby improving RACH functionality and congestion management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple WTRUs share the same PRACH resources for random access, then resource utilization is improved, but preamble collisions and congestion increase

Engineering Contradiction:
Improveresource utilizationVSAvoidpreamble collision rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the shared PRACH resources into multiple dedicated subsets, each assigned to specific WTRUs based on priority levels or service types. This segmentation reduces preamble collisions by ensuring that WTRUs with different priorities use separate resources, while still achieving high resource utilization through comprehensive allocation of all PRACH resources to different priority groups.

Inventive Principle:
Principle #1Segmentation

2Speed

If dedicated PRACH resources are allocated to different priority levels, then transmission priority is improved, but device complexity increases

Engineering Contradiction:
Improvetransmission priorityVSAvoidresource configuration complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent implements dynamic resource allocation where the network can flexibly configure and reconfigure PRACH resource subsets based on current traffic conditions, priority requirements, and system load. This dynamic approach allows the system to adapt to changing conditions without requiring complex static configurations, thereby maintaining manageable device complexity while achieving priority-based transmission.

Inventive Principle:
Principle #15Dynamics

3Productivity

If PRACH resources are allocated based on priority levels, then access efficiency for high-priority traffic is improved, but system complexity increases

Engineering Contradiction:
Improveaccess efficiencyVSAvoidpriority management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring PRACH resource subsets and associating them with specific priority levels before actual random access occurs. The network预先 establishes the mapping between priority levels and resource subsets, so that when WTRUs need to access the network, they can directly select appropriate resources based on their priority without complex real-time decision-making, thereby improving access efficiency while keeping system complexity manageable.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2826288B1Random access procedures in wireless systems
Publication Date: 2018.12.05 INTERDIGITAL PATENT HOLDINGS INC
  • EP2826288B1 patent drawingFigure 1A
  • EP2826288B1 patent drawingFigure 1B
  • EP2826288B1 patent drawingFigure 1C

AI summary

A wireless transmit/receive unit (WTRU) may detect cell congestion by selecting a preamble type as a function of priority level, transmitting the preamble to a serving cell, receiving a random access response (RAR) from the serving cell, determining a congestion state of the serving cell as a function of the received RAR, and/or responding to the congestion state of the serving cell. RACH functionality may be improved by allocating one or more sets of Physical RACH (PRACH) resources to a WTRU. The WTRU may configure the additional PRACH resources based on the allocation. A WTRU may determine a second set of PRACH resources based at least in part on a first set of PRACH resources. A WTRU may determine additional sets of PRACH preambles and may utilize modified PRACH preambles and/or modified PRACH preamble formats. The WTRU may signal additional PRACH resources.