Mobile Station TAG Capability Reporting for Inter-band CA

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Solution Overview

Problem

In mobile communication systems supporting LTE-Advanced, mobile stations cannot effectively notify the number of Timing Adjustment Groups (TAGs) they support, leading to inappropriate CC and TAG mapping by the radio base station during Inter-band CA, which can result in interoperability issues.

Innovation Solution

The mobile station includes a managing unit to manage TAGs and a transmitting unit that notifies the radio base station of the supportable number of TAGs through new information elements like 'supportedTAG-r11' or 'SupportedBandCombination-r10' within the 'UE-EUTRA-Capability' message, allowing the radio base station to set appropriate CC and TAG mappings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the radio base station uses an equal or greater number of TAGs than the number of TAGs a mobile station can support, then TA control can be performed for more carriers, but interoperability between the radio base station and mobile station cannot be guaranteed

Engineering Contradiction:

Improvenumber of TAGs for TA controlVSAvoidinteroperability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The mobile station feeds back its TAG support capability to the radio base station through capability reporting messages. This feedback mechanism enables the base station to adapt its TAG allocation to match the mobile station's actual capabilities, ensuring interoperability while maximizing the number of TAGs utilized for TA control.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the number of TAGs allocated to each mobile station based on reported capabilities. The base station can flexibly configure TAG assignments according to individual mobile station needs and capabilities, rather than using a fixed configuration for all users.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If the radio base station does not know the number of TAGs each mobile station can support, then device complexity is reduced, but appropriate mapping of CCs and TAGs cannot be set

Engineering Contradiction:

Improvecapability information managementVSAvoidCC and TAG mapping

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The mobile station reports its TAG support capability to the radio base station in advance through capability reporting messages before actual TAG allocation occurs. This preliminary information exchange enables the base station to plan and configure appropriate CC-TAG mappings without increasing operational complexity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2840842B1Mobile station and method for mobile station

Publication Date: 2022.05.11 NTT DOCOMO INC

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AI summary

A mobile station UE according to the present invention includes: a managing unit 11 configured to manage one or multiple TAGs each including any of a Pcell and an Scell; an adjusting unit 12 configured to adjust the transmission timings of uplink signals in any of the Pcell and the Scell belonging to the same TAG such that the transmission timings will be the same; and a transmitting unit 13 configured to notify a radio base station eNB of the supportable number of TAGs.