Cell Reselection Redistribution Parameters for IoT Coverage

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Solution Overview

Problem

Current cell reselection methods in mobile communication systems, particularly for machine type communication (MTC) and Internet of Things (IoT) services, face challenges in efficiently distributing radio terminals in idle mode across multiple cells and frequencies, especially in coverage areas extended by enhanced coverage functions, leading to increased cell load due to repetitive transmissions.

Innovation Solution

A cell reselection control method that involves a base station transmitting redistribution parameters through broadcast signaling to radio terminals, allowing them to perform cell reselection based on acquired parameters, thereby distributing cells and frequencies effectively in both normal and enhanced coverage areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single redistribution parameter is used for all radio terminals, then the system is simple to operate, but radio terminals in extended coverage areas cannot be appropriately distributed across cells and frequencies

Engineering Contradiction:

Improvesimplicity of redistribution parameter applicationVSAvoidadaptability to different coverage areas

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The redistribution parameters are segmented into at least two distinct sets: a first redistribution parameter for radio terminals in normal coverage areas and a second redistribution parameter for radio terminals in extended coverage areas. The base station transmits both parameters and indicates which one should be applied based on the terminal's coverage type, enabling differentiated control for different coverage scenarios.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different redistribution parameters are applied to different local conditions (coverage areas). The first redistribution parameter is specifically applied to terminals in normal coverage areas, while the second redistribution parameter is applied to terminals in extended coverage areas. This local quality approach ensures that each terminal receives appropriate redistribution control tailored to its specific coverage environment.

Inventive Principle:

Principle #3Local quality

2Device complexity

If radio terminals in extended coverage areas use the same cell reselection method as normal coverage areas, then the system is easy to manage, but cell load increases due to repetitive transmissions

Engineering Contradiction:

Improvecomplexity of cell reselection managementVSAvoidcell load

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The cell reselection control is segmented by coverage area type. Terminals in extended coverage areas use the second redistribution parameter which is specifically designed to distribute these terminals across multiple cells and frequencies, thereby reducing the concentration of terminals on single cells and reducing overall cell load caused by repetitive transmissions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different redistribution parameters with different parameter values are used for different coverage areas. The second redistribution parameter for extended coverage areas is configured to achieve appropriate distribution of terminals, changing the reselection behavior to reduce cell load compared to using the first redistribution parameter designed for normal coverage areas.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If redistribution parameters are transmitted separately for different coverage areas, then appropriate distribution is achieved, but the signaling complexity increases

Engineering Contradiction:

Improveadaptability to different coverage areasVSAvoidcomplexity of parameter transmission

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The base station merges the transmission of multiple redistribution parameters into a single broadcast signaling message. Both the first redistribution parameter and the second redistribution parameter are transmitted together through broadcast signaling, along with an indication of which parameter should be applied. This reduces signaling complexity compared to separate transmissions while maintaining the ability to provide differentiated parameters for different coverage areas.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11388646B2Cell reselection control method, base station, and radio terminal

Publication Date: 2022.07.12 KYOCERA CORP

AI summary

A cell reselection control method according to one embodiment is a method in a mobile communication system. The cell reselection control method a step A of transmitting through a use of broadcast signaling, by a base station, as a redistribution parameter used for a redistribution function, a first redistribution parameter applied to a radio terminal in a first coverage and a second redistribution parameter applied to a radio terminal in a second coverage outside the first coverage, a step B of acquiring, by a radio terminal in an idle mode in the second coverage, the second redistribution parameter transmitted in the step A, and a step C of performing, by the radio terminal, cell reselection using the second redistribution parameter acquired in the step B. The redistribution function is a function of distributing cells and/or frequencies which a plurality of radio terminals in an idle mode reselects by cell reselection. The second coverage is a coverage extended by an enhanced coverage function including repetitive transmissions.