Mobile Station CC-to-TAG Mapping for Uplink Carrier Aggregation

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Solution Overview

Problem

In mobile communication systems supporting LTE-Advanced, the radio base station cannot configure appropriate CC-to-TAG mapping for mobile stations performing UL CA, leading to potential interoperability issues between the radio base station and the mobile station.

Innovation Solution

A mobile station equipped with a management unit for managing timing advance groups, an adjustment unit for synchronizing uplink signal timings, and a transmission unit that notifies the radio base station of supported bands, component carriers, and settable timing advance groups, enabling the radio base station to configure appropriate CC-to-TAG mapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the mobile station does not notify the radio base station of settable timing advance groups, then the notification overhead is reduced, but the radio base station cannot configure appropriate CC-to-TAG mapping

Engineering Contradiction:

Improveinformation notification overheadVSAvoidCC-to-TAG mapping configuration reliability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The mobile station performs preliminary action by notifying the radio base station in advance about the settable timing advance groups before carrier aggregation configuration. This allows the base station to have the necessary information ready for proper CC-to-TAG mapping configuration, resolving the contradiction between minimizing notification overhead and ensuring configuration reliability.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the mobile station notifies all possible timing advance group combinations, then the radio base station can configure optimal CC-to-TAG mapping, but the notification overhead increases significantly

Engineering Contradiction:

ImproveCC-to-TAG mapping configuration reliabilityVSAvoidinformation notification overhead

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The mobile station applies local quality by notifying only the specific timing advance groups that are settable for each component carrier rather than all possible combinations. This targeted notification approach provides the radio base station with sufficient information for optimal CC-to-TAG mapping while significantly reducing the notification overhead compared to notifying all possible combinations.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If multiple timing advance groups are managed without proper CC-to-TAG mapping, then carrier aggregation flexibility is maintained, but transmission timing synchronization cannot be ensured

Engineering Contradiction:

Improvecarrier aggregation flexibilityVSAvoidtransmission timing synchronization reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The mobile station provides feedback to the radio base station about which timing advance groups can be set for each component carrier. This feedback mechanism enables the base station to configure appropriate CC-to-TAG mapping that maintains carrier aggregation flexibility while ensuring transmission timing synchronization reliability through proper grouping of carriers with equivalent radio characteristics.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9936471B2Mobile station for performing component carrier-to-timing advance group mapping

Publication Date: 2018.04.03 NTT DOCOMO INC

AI summary

Appropriate CC-to-TAG mapping is configured when “UL CA” is performed. A mobile station UE of the invention includes: a management unit 11 configured to manage one or more TAGS; an adjustment unit 12 configured to make adjustment to synchronize transmission timings of uplink signals within CCs which belong to the same TAG; and a transmission unit 13 configured to notify a radio base station eNB of a combination of supported bands, supported CCs, and settable TAGS, and the bands and the CCs grouped in the TAGs included in the combination.