Terminal Uplink Timing Alignment for Cross-Carrier ACK/NACK Reporting
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Solution Overview
Problem
In LTE-A systems with varying UL-DL configurations across component carriers, the complexity and resource requirements for error detection and response signaling increase, leading to inefficient use of A/N resources and decoding processing in both terminals and base stations.
Innovation Solution
A terminal apparatus and transmission method that synchronizes UL-DL configurations across component carriers, allowing for efficient reporting and decoding of error detection results without increasing resource usage or processing complexity, by aligning UL subframe timings and using aligned reporting mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different UL-DL configurations are set for each component carrier to provide flexible service support, then adaptability is improved, but device complexity and resource requirements increase
Solution Approach 1:
The patent segments component carriers into different groups based on their UL-DL configurations. Terminals only perform error detection and response signaling for component carriers within their assigned group, rather than processing all component carriers. This segmentation reduces the complexity and resource requirements for error detection while maintaining the ability to support multiple UL-DL configurations across different component carriers.
2Measurement precision
If error detection results are reported for each component carrier independently, then measurement precision is improved, but loss of time and resource efficiency worsen
Solution Approach 1:
The patent merges the error detection and response signaling operations for multiple component carriers into a unified group-based process. Instead of independently processing each component carrier, terminals group component carriers by UL-DL configuration and perform error detection and response signaling at the group level. This merging maintains error detection accuracy while significantly reducing the time and resources required for response signaling.
3Reliability
If A/N resources are allocated for each component carrier, then reliability is improved, but loss of substance (resource efficiency) worsens
Solution Approach 1:
The patent makes A/N resources universal by allocating them at the group level rather than at the individual component carrier level. A single set of A/N resources serves multiple component carriers within a group, allowing the same resources to be reused across different component carriers. This multi-functional use of A/N resources maintains error detection reliability while reducing overall resource consumption.
Data Source
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AI summary
The purpose of the present invention is to inhibit an increase in the amount of A/N resources, without changing the timing at which the error detection result of an SCell is notified when UL-DL configurations to be configured for each of the unit bands are different, from the timing at which the error detection result is notified when just a single unit band is configured. A control unit (208) transmits, using a first unit band, a response signal including error detection results about data received with both the first unit band and a second unit band. In a first composition pattern set for the first unit band, an uplink communication subframe is set to be the same timing as at least an uplink communication subframe of a second composition pattern set for the second unit band.