Group Call Channel Allocation in Trunking Systems

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Solution Overview

Problem

Conventional mobile communication systems waste radio channel resources by using two Traffic Channels (TCHs) for group calls and broadcasts, with one channel always reserved for the initiator or talker, leading to inefficient resource utilization.

Innovation Solution

Assigning a Stand-alone Dedicated Control Channel (SDCCH) for Mobile Stations (MS) and establishing a group call or broadcast channel, allowing the MS to switch from the SDCCH to a single group call or broadcast channel, thereby releasing the SDCCH and optimizing channel usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two TCHs are used for group call initiation (one dedicated TCH for initiator and one group call channel), then the group call can be established reliably, but radio channel resources are wasted

Engineering Contradiction:
Improvegroup call establishment reliabilityVSAvoidradio channel resource waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent merges the control channel function and the group call channel function into a single TCH. The initiator uses one TCH for both control signaling (via SDCCH) and group call participation, eliminating the need for a separate dedicated TCH while maintaining reliable group call establishment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single TCH assigned to the initiator serves multiple functions: it acts as both the control channel for call setup and the group call channel for actual communication. This multi-functional approach reduces resource consumption while maintaining service reliability.

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

2Ease of operation

If a dedicated TCH is always reserved for the initiator during group call, then the initiator can maintain talker status, but channel resources are inefficiently utilized

Engineering Contradiction:
Improveinitiator talker status maintenanceVSAvoidchannel resource utilization efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent implements dynamic channel allocation where the initiator's TCH assignment changes based on operational phase. During call setup, the initiator uses SDCCH for control; during active talker status, the initiator uses the group call channel. This dynamic switching optimizes resource utilization while maintaining ease of operation.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1858275B1Method and system for implementing group call service
Publication Date: 2009.07.22 HUAWEI TECH CO LTD
  • EP1858275B1 patent drawingFigure 1
  • EP1858275B1 patent drawingFigure 2
  • EP1858275B1 patent drawingFigure 3

AI summary

A method and system for providing group call service in trunking communication technology are provided. The method includes: allocating an SDCCH by a BSC for an MS; accessing the network and initiating a group call request by the MS; establishing a group call control connection and establishing a group call channel for every cell in group call area; assigning the MS to the group call channel from the SDCCH, and releasing the SDCCH. According to the above solution, only one TCH which is used as group channel, is needed to initiate group call service, no extra TCH is needed for the initiator. In this way, the channel waste in the standard VGCS initiation process is solved.