Random Access Contention Detection via C-RNTI Signaling

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Solution Overview

Problem

The conventional random access procedure in mobile communication systems, such as 3GPP LTE, incurs high signaling overhead due to the need for a Contention Resolution (CR) message to be transmitted on the DownLink for each User Equipment (UE) during the random access procedure, especially when contention occurs.

Innovation Solution

A method where the User Equipment (UE) determines successful contention resolution by receiving User-specific control information addressable by a Cell-Radio Network Temporary Identifier (C-RNTI) from the Base Station, reducing the need for a CR message transmission by using a timer and sensing control information on the DownLink channel, and re-starting the procedure if no information is received within the timer's expiration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a Contention Resolution message is transmitted on the DownLink for each User Equipment during the random access procedure, then successful contention resolution can be achieved, but signaling overhead increases significantly

Engineering Contradiction:

Improvecontention resolution reliabilityVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the contention resolution function from the traditional CR message transmission mechanism. Instead of transmitting a dedicated CR message for each UE, the system extracts only the essential information (contention resolution indication) and conveys it through existing downlink control information channels, thereby eliminating redundant signaling while preserving the core contention resolution functionality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent makes the downlink control information serve multiple functions: it simultaneously carries scheduling information and contention resolution indication. By embedding the contention resolution bit within the existing downlink control structure, the system achieves multi-functionality without requiring additional dedicated messaging, thus reducing overall signaling overhead while maintaining reliable contention resolution

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If a Contention Resolution message is transmitted for each UE, then contention detection accuracy is improved, but system resource consumption increases

Engineering Contradiction:

Improvecontention detection accuracyVSAvoidsystem resource consumption

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent merges the contention resolution indication with existing downlink control information that is already being transmitted for scheduling purposes. By combining these functions into a single transmission, the system achieves accurate contention detection without the additional energy cost of separate CR message transmissions, thereby reducing system resource consumption while maintaining detection accuracy

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11297656B2Method and apparatus for detecting contention during random access procedure in a mobile communication system

Publication Date: 2022.04.05 SAMSUNG ELECTRONICS CO LTD

AI summary

A method is provided for performing a random access procedure in a mobile communication system. The method includes receiving a random access response message from a Base Station (BS); transmitting a message including a Cell-Radio Network Temporary Identifier (C-RNTI) to the BS, if the C-RNTI exists; and determining that a contention for the random access procedure is resolved successfully, when User Equipment (UE)-specific control information addressable by the C-RNTI is received from the BS.