PRACH Carrier Selection in Multicarrier Wireless Systems

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Solution Overview

Problem

In wireless communication systems with multiple carriers, existing random access procedures are inefficient due to the lack of effective methods for selecting the appropriate uplink carrier and associating it with the correct downlink carrier, leading to suboptimal resource utilization and increased interference.

Innovation Solution

The system enables user equipment (UE) to select an uplink carrier for random access and aggregate pilot signals to redirect itself based on pilot signals, while defining specific Physical Random Access Channel (PRACH) parameters to identify the corresponding downlink carrier, allowing for efficient resource allocation and interference clearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple downlink carriers are associated with one uplink carrier in a multiple carrier environment, then the system can support asymmetric bandwidth and heterogeneous networks, but the random access procedure becomes inefficient and resource utilization deteriorates

Engineering Contradiction:
Improvesupport for asymmetric bandwidth and heterogeneous networksVSAvoidrandom access efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent segments the association between uplink and downlink carriers by introducing a one-to-many mapping relationship where one uplink carrier can be associated with multiple downlink carriers. This segmentation allows the system to handle asymmetric bandwidth configurations and heterogeneous networks while maintaining efficient random access procedures through structured carrier pairing.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If existing random access procedures are used in multiple carrier environments, then the procedure is simple, but resource utilization is suboptimal and interference increases

Engineering Contradiction:
Improverandom access procedure simplicityVSAvoidresource utilization efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent implements feedback mechanisms in the random access procedure where the base station provides feedback information to the user equipment about carrier associations and resource allocation. This feedback loop enables optimized resource utilization and interference management while maintaining procedural simplicity through automated carrier selection and association based on feedback signals.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2351444B1Physical random access channel (PRACH) transmission in multicarrier operation
Publication Date: 2018.11.28 QUALCOMM INC
  • EP2351444B1 patent drawingFigure 1
  • EP2351444B1 patent drawingFigure 2
  • EP2351444B1 patent drawingFigure 3

AI summary

Systems and methodologies are described that facilitate selecting an uplink carrier for random access within a wireless environment having multiple carriers. Selection of an uplink carrier for random access can be randomly selected from a set of available uplink carriers. Additionally, the uplink carrier for random access can be selected based upon which uplink carrier is paired with an anchor carrier. Further, the uplink carrier for random access can be identified based upon a bandwidth related to the user equipment (UE). Reference signals can also be employed in order to identify an uplink carrier to perform random access.