Carrier Aggregation Feedback for TDD Configurations
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Solution Overview
Problem
Current LTE-A systems face challenges in efficiently aggregating carriers with different TDD uplink/downlink configurations, leading to interference and limitations in ACK/NACK feedback transmission, especially when multiple carriers are aggregated, as existing methods cannot effectively handle diverse TDD configurations and spatial bundling requirements.
Innovation Solution
A method and apparatus for aggregating carriers using PUCCH format 1b with channel selection, where the number of sub-frames for ACK/NACK feedback is determined from the largest TDD uplink/downlink configuration, allowing for Q*M bits of feedback information generation and mapping, and channel resources are selected based on this configuration to ensure accurate and efficient feedback transmission across different TDD and FDD carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carriers with different TDD uplink/downlink configurations are aggregated, then system bandwidth and data rate are improved, but interference between TDD systems at adjacent frequencies occurs
Solution Approach 1:
The system segments carriers into different TDD uplink/downlink configurations (Configuration 1 and Configuration 2), allowing each carrier to operate with its own timing structure. This segmentation enables carriers to be aggregated while maintaining different uplink/downlink patterns, achieving high data rates without TDD interference between adjacent frequencies.
2Productivity
If multiple carriers with different TDD configurations are aggregated, then system capacity is improved, but ACK/NACK feedback transmission becomes complex and difficult to manage
Solution Approach 1:
The patent implements a universal PUCCH feedback mechanism that works across carriers with different TDD configurations. By using PUCCH format 1b with channel selection, the system provides a multi-functional feedback solution that handles ACK/NACK transmission uniformly regardless of which TDD configuration (1 or 2) each carrier uses, thereby managing complexity while maintaining high system capacity.
Solution Approach 2:
The patent introduces an intermediary mapping mechanism that translates feedback requirements from multiple carriers with different TDD configurations into a unified PUCCH feedback structure. This intermediary layer (the feedback mapping and channel selection mechanism) mediates between the diverse carrier configurations and the single PUCCH resource, simplifying the overall feedback transmission process.
3Productivity
If PUCCH format 1b with channel selection is used for feedback, then feedback transmission efficiency is improved, but the number of sub-frames for ACK/NACK feedback increases making resource allocation difficult
Solution Approach 1:
The patent merges ACK/NACK feedback from multiple sub-frames into a single PUCCH transmission using format 1b with channel selection. By combining feedback information across multiple sub-frames (M sub-frames) into one consolidated feedback message, the system improves transmission efficiency while managing the quantity of feedback sub-frames through the channel selection mechanism.
Data Source
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AI summary
Disclosed are a carrier aggregation feedback method, device and system for different TDD uplink/downlink configurations, relating to communication technologies. The number M of subframes requiring ACK/NACK feedback in a current uplink subframe is determined according to a TDD uplink/downlink configuration that corresponds to each carrier and is used for determining a timing relationship based on which a UE reports ACK/NACK feedback information of the carrier, and then ACK/NACK feedback information transmitted by a terminal device in the current uplink subframe and a candidate channel resource used for channel selection are determined according to the value of M, so as to transmit the ACK/NACK feedback information in the candidate channel resource by using PUCCH format 1b in combination with channel selection.