Mobile Station HARQ Feedback for Multi-Carrier Systems
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Solution Overview
Problem
In conventional mobile communication systems using a wide frequency band composed of multiple component carriers, the quality of HARQ control information transmission between base station and mobile station apparatuses is not clearly defined, leading to reduced throughput due to unclear exchange mechanisms.
Innovation Solution
A mobile station apparatus and communication method that transmit HARQ control information with high quality by indicating NACK or DTX for deactivated downlink component carriers, allowing for explicit notification of ACK, NACK, and DTX states, thereby preventing unnecessary retransmissions and improving signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If frequency band aggregation is used to expand communication bandwidth, then communication speed is improved, but HARQ control information quality deteriorates due to unclear exchange mechanisms
Solution Approach 1:
The patent segments the HARQ feedback mechanism by separately handling ACK/NACK information for activated component carriers and NACK information for deactivated component carriers. This segmentation allows the system to maintain high communication speed through frequency band aggregation while ensuring reliable HARQ control information transmission by clearly defining feedback requirements for each carrier state.
Solution Approach 2:
The patent changes the parameter of HARQ feedback content based on component carrier activation state. When a component carrier is deactivated, the mobile station transmits only NACK information for that carrier rather than full ACK/NACK feedback, optimizing the feedback mechanism for different operational states and maintaining reliability across aggregated frequency bands.
2Productivity
If multiple component carriers are activated for wide frequency band communication, then throughput is improved, but system complexity increases due to multiple HARQ feedback management requirements
Solution Approach 1:
The patent implements a dynamic HARQ feedback management mechanism where the base station can activate or deactivate component carriers based on channel conditions and traffic requirements. The mobile station dynamically adjusts its feedback transmission accordingly, transmitting detailed ACK/NACK information only for activated carriers and simplified NACK information for deactivated carriers, thereby managing complexity while maintaining high throughput.
Solution Approach 2:
The patent applies the principle of discarding detailed feedback for deactivated component carriers and recovering it only when needed. When a component carrier is deactivated, the system discards the requirement for full ACK/NACK feedback for that carrier, reducing immediate complexity. The feedback mechanism recovers full functionality when the carrier is reactivated, allowing the system to scale complexity with actual usage requirements.
Data Source
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AI summary
Disclosed is a mobile communication system and a mobile communication method which enable high-quality transmission and reception of hybrid automatic repeat request (HARQ) control information in case that a base station apparatus and a mobile station apparatus communicate using a wide frequency band made up of a plurality of component carriers. In a mobile communication system where a base station apparatus and a mobile station apparatus communicate using a plurality of downlink component carriers, the base station apparatus allocates a physical uplink shared channel (PUSCH) resource to the mobile station apparatus for the transmission of the HARQ control information, and the mobile station apparatus uses the PUSCH resource to transmit the HARQ control information to the base station apparatus.