Random Access on Small Cell Under Dual Connectivity

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Solution Overview

Problem

There is no technical solution for random access of User Equipment (UE) on a small cell under dual connectivity in existing LTE systems, which hinders efficient data communication and synchronization.

Innovation Solution

A method and system for conducting random access on a small cell under dual connectivity, where the UE initiates a random access process and receives a dedicated random access preamble parameter from the base station, allowing it to send the preamble to the small cell and receive a response message, facilitating synchronization and data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If dual connectivity is implemented to improve user throughput and mobility, then data communication capability is enhanced, but random access mechanism complexity increases due to multiple base stations and TA groups

Engineering Contradiction:
Improveuser throughputVSAvoidrandom access mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the random access mechanism by introducing separate random access procedures for PTAG and STAG. PTAG uses a simplified two-step process while STAG uses a four-step process, allowing each segment to be optimized independently for its specific requirements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary TA group identifier in the random access response message that indicates whether the response is for PTAG or STAG. This intermediary element allows the system to manage multiple random access procedures without requiring the UE to independently track complex procedures for each base station

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple TAs are introduced to solve coverage and synchronization problems in carrier aggregation, then synchronization reliability is improved, but management complexity increases with multiple TA groups

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidTA group management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides serving cells into two distinct TA groups (PTAG and STAG) with different random access characteristics. This segmentation allows the system to maintain reliable synchronization for each group type while managing complexity through standardized procedures for each group

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the random access parameters based on TA group type. PTAG uses parameters similar to traditional single-TA systems, while STAG uses parameters optimized for small cell scenarios, allowing each group to operate with appropriate parameters without increasing overall system complexity

Inventive Principle:
Principle #35Parameter changes

3Productivity

If small cells are deployed to improve hotspot coverage and data traffic handling, then network capacity is enhanced, but signal attenuation and coverage limitations increase due to high frequency points

Engineering Contradiction:
Improvenetwork capacityVSAvoidsignal attenuation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary uplink synchronization through the random access procedure before actual data transmission begins. By establishing timing alignment in advance through the random access response and TA value, the system ensures that subsequent data transmissions experience minimal signal degradation and synchronization issues

Inventive Principle:
Principle #10Preliminary action

4Reliability

If conflicting random access process is used for STAG to ensure proper synchronization, then uplink timing alignment is achieved, but access time increases due to four-step resolution process

Engineering Contradiction:
Improveuplink timing alignmentVSAvoidaccess time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary configuration of dedicated random access preambles for STAG through RRC signaling before the actual random access occurs. This preliminary action allows the UE to have pre-assigned resources, reducing the need for conflict resolution and enabling faster access while maintaining reliable timing alignment

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3051914B1Method and system for conducting random access on small cell under dual connections
Publication Date: 2019.07.17 ZTE CORP
  • EP3051914B1 patent drawingFigure 1~2
  • EP3051914B1 patent drawingFigure 3~4
  • EP3051914B1 patent drawingFigure 5

AI summary

Disclosed is a method for conducting random access on a small cell under dual connectivity. The method includes that: a User Equipment (UE) sends a dedicated random access preamble corresponding to a designated small cell to a base station to which the designated small cell belongs on the designated small cell; and the UE receives a random access response message sent by a base station to which a master control cell in dual connectivity belongs or the base station to which the designated small cell belongs. The present disclosure also discloses a system for conducting random access on a small cell under dual connectivity, a base station, a UE and a computer storage medium.