Group Traffic Channel for Multicast Data in UMTS and LTE

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Solution Overview

Problem

In the UMTS system, group-cast messages cannot be transmitted due to limited FACH resources, and in the LTE system, transmitting group-cast data as system information disrupts scheduling, leading to unsatisfactory Quality of Service and complex system information management.

Innovation Solution

A method and device for transmitting data using a radio access network that receives data from a core network and transmits it to User Equipments (UEs) over a user plane shared resource, specifically using a Group Traffic Channel (GTCH) in LTE, allowing for efficient mapping onto Physical Downlink Shared and Control Channels, and scheduling information is transmitted to ensure timely and resource-efficient data delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If group-cast data is transmitted as system information in LTE system, then group-cast functionality is achieved, but system information scheduling is disrupted and complexity increases

Engineering Contradiction:
Improvegroup-cast functionalityVSAvoidsystem information scheduling complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the transmission of group-cast data from system information by introducing a separate logical channel (CTCH) and transport channel (RACH) specifically for group-cast messages. This segmentation allows group-cast data to be transmitted independently without disrupting the existing system information scheduling mechanisms, thereby achieving group-cast functionality while maintaining system information management simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism by using a dedicated random access channel (RACH) for group-cast message transmission. This intermediary channel acts as a mediator between the group-cast data source and the target UEs, allowing group-cast communication to occur without directly interfering with the system information broadcast path, thus avoiding scheduling disruptions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If downlink broadcast data is transmitted over FACH and SCCPCH in UMTS system, then broadcast functionality is provided, but QoS becomes unsatisfactory and FACH resources are limited

Engineering Contradiction:
Improvebroadcast functionalityVSAvoidQuality of Service
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the broadcast data transmission by separating it from the conventional FACH and SCCPCH channels. It introduces a dedicated group-cast transmission path using CTCH logical channel and RACH transport channel, which is specifically designed to handle group-cast traffic. This segmentation allows broadcast functionality to be maintained while avoiding the resource limitations and QoS issues of the shared FACH and SCCPCH channels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enhances the universality of the RACH by making it capable of handling both traditional random access functions and group-cast data transmission. This multi-functional use of RACH allows the system to provide reliable group-cast service without requiring additional dedicated broadcast channels, thereby improving QoS while maintaining resource efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If FACH resources are occupied by CTCH traffic, then broadcast data can be transmitted, but random access success ratio decreases

Engineering Contradiction:
Improvebroadcast data transmissionVSAvoidrandom access success ratio
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the traffic by creating a dedicated RACH transport channel specifically for group-cast messages, separating it from the FACH channel. This segmentation ensures that CTCH traffic does not occupy FACH resources, thereby maintaining both broadcast data transmission capability and random access success ratio without resource conflict.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a copy of the random access mechanism by introducing a dedicated RACH for group-cast purposes. This copied random access path allows group-cast messages to be transmitted without competing with regular random access traffic on FACH, thus preserving random access success ratio while enabling efficient group-cast data transmission.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2916571B1Method and device for transmitting data
Publication Date: 2020.04.22 CHINA ACAD OF TELECOMM TECH
  • EP2916571B1 patent drawingFigure 1~2
  • EP2916571B1 patent drawingFigure 3~4
  • EP2916571B1 patent drawingFigure 5~6

AI summary

The embodiments of the present application relate to the technical field of wireless communications, and in particular, to a method, system and device for transmitting data, so as to solve the problems existing in the prior art that a multicast message cannot be sent due to FACH limitation in a UMTS system, and a relatively large influence will be brought to the current system information scheduling mechanism if multicast data is issued through system information in an LTE system. The method of the embodiments of the present application comprises: a wireless access network receiving data of at least one group of user equipment from a core network, and the wireless access network transmitting data of a corresponding group to the user equipment in the group through user plane shared resource transmission. Due to this mode of adopting a shared channel to bear multicast data, the current relatively limited FACH resource in a UMTS system is thereby released, and the adoption of a shared channel can enable transfer of multicast data more rapidly and promptly. An LTE adopts a user plane to transmit multicast data, avoiding influence on the system information.