Inter-site Carrier Aggregation Scell Activation Feedback

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Solution Overview

Problem

In inter-site Carrier Aggregation (CA) scenarios, radio base stations face challenges in recognizing when a Secondary cell (Scell) is activated, as the station transmitting the 'Activate command' may differ from the one managing the Scell, leading to uncertainties in scheduling capabilities.

Innovation Solution

A radio base station configured to transmit an 'Activate command' to a mobile station, which then executes a random access procedure with the managing radio base station, ensuring notification of the Scell activation to the managing base station, thereby facilitating proper communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a radio base station transmits an 'Activate command' to activate an Scell managed by a different radio base station, then the mobile station can perform communications using the Scell, but the managing radio base station cannot recognize when the Scell is activated

Engineering Contradiction:

ImproveInter-site CA capabilityVSAvoidScell activation status information

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism where the mobile station notifies the managing radio base station (eNB #10) of Scell activation status through uplink signals such as SRS (Sounding Reference Signal) or PUCCH (Physical Uplink Control Channel). This feedback allows eNB #10 to recognize when the Scell is activated and determine scheduling timing, resolving the information loss problem while maintaining Inter-site CA capability

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The mobile station acts as an intermediary that bridges the information gap between eNB #1 (which transmits the Activate command) and eNB #10 (which manages the Scell). Through the mobile station's feedback mechanisms, activation status information is transmitted from the user equipment to the managing base station, enabling proper coordination without requiring direct communication between base stations

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the managing radio base station does not know when the Scell is activated, then scheduling cannot be performed properly in the Scell

Engineering Contradiction:

ImproveCommunication reliabilityVSAvoidScheduling efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the traditional mechanical signaling method (direct base station-to-base station notification) with a signal processing approach using uplink reference signals. The managing base station detects Scell activation by analyzing SRS signals or PUCCH transmissions from the mobile station, enabling reliable and efficient activation recognition without additional dedicated signaling overhead

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11219067B2Radio base station and mobile station for performing communications by aggregating cells under different radio base stations

Publication Date: 2022.01.04 NTT DOCOMO INC

AI summary

An objective is to enable communications properly using an Scell even in a case where a radio base station which transmits “Activate command” and a radio base station which manages an Scell are different when “Inter-site CA” is performed. A radio base station eNB #1 according to the invention includes a transmission unit 12 configured to transmit an “Activate command” which is a command to activate a cell #B to a mobile station UE and thereafter notify a radio base station eNB #10 that the cell #B is activated.