RRC Connection Establishment Bypassing Initial RACH Procedure

Solution Overview

Problem

The initial RACH procedure in 5G communication systems causes latency issues during idle-to-active state transitions and handovers due to the need for transmitting and receiving RA preamble messages, which increases latency, especially in beam-based access at high frequency bands.

Innovation Solution

The method involves storing a timing advance value from a RA response message and using it to establish an RRC layer connection with a base station without transmitting an RA preamble message, along with pre-allocated uplink resources, thereby bypassing the initial RACH procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the initial RACH procedure is performed to establish RRC layer connection, then the connection can be established between terminal and base station, but latency increases due to transmitting and receiving RA preamble messages

Engineering Contradiction:

ImproveRRC connection establishmentVSAvoidlatency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The terminal performs the RACH procedure in advance during the idle state to acquire timing advance values and uplink resources before transitioning to active state. This preliminary action stores synchronization information that can be reused during handover or active state transitions, eliminating the need to perform RACH again and thus reducing latency while maintaining reliable connection establishment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts and stores essential synchronization information (timing advance values and uplink resources) from the RACH procedure results. By separating these critical parameters from the complete RACH procedure and storing them for future use, the system can bypass the full RACH process during subsequent connections, reducing latency while ensuring reliable connection establishment.

Inventive Principle:

Principle #2Taking out (Extraction)

2Adaptability or versatility

If the RACH procedure is performed during idle-to-active state transition, then the terminal can transition to active state, but latency increases due to the initial RACH procedure

Engineering Contradiction:

Improvestate transitionVSAvoidlatency

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The terminal performs the RACH procedure in advance during the idle state to acquire timing advance values and uplink resources before transitioning to active state. This preliminary action stores synchronization information that can be reused during handover or active state transitions, eliminating the need to perform RACH again and thus reducing latency while maintaining reliable connection establishment.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the RACH procedure is performed during handover, then the terminal can handover to target base station, but latency increases due to transmitting RA preamble messages

Engineering Contradiction:

ImprovehandoverVSAvoidlatency

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The terminal performs the RACH procedure in advance during the idle state to acquire timing advance values and uplink resources before transitioning to active state. This preliminary action stores synchronization information that can be reused during handover or active state transitions, eliminating the need to perform RACH again and thus reducing latency while maintaining reliable connection establishment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The timing advance values and uplink resources acquired during the initial RACH procedure are designed to be universally applicable across different scenarios including idle-to-active transitions and handovers. This multi-functionality allows the same stored parameters to serve multiple connection establishment purposes, reducing latency in various operational contexts without requiring scenario-specific procedures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11582810B2Method and apparatus for establishing connection between terminal and base station

Publication Date: 2023.02.14 SAMSUNG ELECTRONICS CO LTD

AI summary

According to an embodiment of the present disclosure, a terminal may store a time correction value acquired from an RA response message during an RRC layer connection to a base station, receive, from the base station, an uplink resource allocation message including an uplink resource allocated to the terminal, after the RRC layer connection to the base station is released, and when an RRC layer connection to the base station is determined, establish the RRC layer connection to the base station without transmitting an RA preamble message, on the basis of the stored time correction value and the allocated uplink resource.