ACK/NACK Bundling in LTE-A Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, particularly in LTE-A, the existing methods for transmitting ACK/NACK feedback information are inefficient, leading to increased resource consumption and potential waste, as they require multiple control channels and complex error handling due to the increased number of ACK/NACK states needed for multiple carriers.
Innovation Solution
The method involves configuring ACK/NACK states into either a single state or multiple states based on predetermined conditions, such as the number of NACKs or carrier groups, to reduce the feedback information rate and optimize resource usage by bundling or multiplexing ACK/NACK signals across carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple ACK/NACK states are transmitted for each data unit in carrier aggregation, then feedback information completeness is improved, but feedback information rate and control channel resource consumption increase
Solution Approach 1:
The patent combines multiple ACK/NACK feedback states into a single bundled state. When multiple data units are received across aggregated carriers, instead of transmitting separate ACK/NACK for each, the method bundles them into one composite feedback signal that represents the overall reception status, thereby reducing feedback information rate while maintaining completeness
Solution Approach 2:
The patent segments feedback transmission by introducing a determination step that decides whether to use bundled or separate ACK/NACK states based on system conditions. This segmentation allows flexible adaptation: bundling is used when resource efficiency is priority, while separate states are used when detailed feedback is needed, thus resolving the contradiction between completeness and resource consumption
2Reliability
If separate control channels are allocated for each ACK/NACK state, then feedback reliability is improved, but control channel resource consumption increases
Solution Approach 1:
The patent merges multiple control channel allocations into a single control channel for bundled ACK/NACK feedback. By combining feedback from multiple data units into one state, the system requires only one control channel allocation instead of multiple separate allocations, thereby reducing control channel resource consumption while maintaining feedback reliability through the bundled information
3Quantity of substance
If ACK/NACK bundling is implemented, then control channel resources are reduced, but feedback information detail is lost
Solution Approach 1:
The patent implements dynamic feedback mode selection that can switch between bundled ACK/NACK state and separate ACK/NACK states based on system conditions, data unit characteristics, and resource availability. This dynamic approach allows the system to optimize between resource efficiency and information detail on demand, resolving the contradiction by making the feedback granularity adjustable rather than fixed
Data Source
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AI summary
The present invention relates to a method in which a receiver transmits control information in a wireless communication system. The method comprises a step of receiving a plurality of data units from a transmitter, a step of determining acknowledgement/negative-acknowledgement (ACK/NACK) states for each of the data units; and a step of transmitting, to the transmitter, the ACK/NACK states in multiple ACK/NACK states or in a single ACK/NACK state in accordance with a predetermined condition.