PUCCH Joint Coding for ACK/NACK Reliability
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Solution Overview
Problem
In LTE-A systems, the existing PUCCH feedback method for ACK/NACK information has limited reliability due to short minimum Hamming distance, leading to potential information loss and unnecessary retransmissions, which negatively impacts communication quality.
Innovation Solution
A method involving joint coding and modulation of ACK/NACK information, sent using the second pilot symbol of each slot across multiple orthogonal PUCCH resources, which increases the minimum Hamming distance and enhances feedback quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeated coding is used to send ACK/NACK information on multiple antennas, then the transmission can be performed across multiple PUCCH resources, but the minimum Hamming distance remains short and feedback performance is limited
Solution Approach 1:
The patent merges the ACK/NACK information with CSI information in a joint coding process. The ACK/NACK bits are combined with CSI bits and encoded together using a convolutional code, creating a unified coded sequence that is then modulated and sent across multiple PUCCH resources. This merging approach allows the ACK/NACK information to benefit from the redundancy and error correction capabilities of the joint coding structure, thereby improving feedback performance without requiring separate complex coding for each antenna.
2Reliability
If traditional separate coding is used for ACK/NACK information, then the transmission structure remains simple, but errors occur more easily leading to information loss and unnecessary retransmissions
Solution Approach 1:
The patent implements a universal coding structure where the same joint coding process is applied to both CSI and ACK/NACK information. The convolutional code serves multiple functions: it encodes the CSI information, simultaneously encodes the ACK/NACK information, and provides error correction for both types of data. This multi-functional approach ensures that ACK/NACK information receives the same level of protection as CSI information, preventing errors and information loss while avoiding unnecessary retransmissions.
3Reliability
If the minimum Hamming distance is increased through better coding, then feedback reliability improves, but the coding and modulation processing becomes more complex
Solution Approach 1:
The patent changes the coding parameters by using a convolutional code with specific constraint lengths and generator polynomials that are optimized for PUCCH format 2b. The joint coding process uses a rate 1/2 convolutional code with constraint length K=7 and generator polynomials g(1)=133 and g(2)=171, which provides optimal error correction performance for the given resource constraints. This parameter optimization increases the minimum Hamming distance of the coded sequence, improving feedback quality while keeping the processing complexity manageable through standard convolutional coding algorithms.
Data Source
AI summary
The present invention provides a method and apparatus for sending a Physical Uplink Control Channel (PUCCH), which includes: performing a joint coding and modulation processing on Acknowledgement/Negative Acknowledgement (ACK/NACK) information which is required to be sent simultaneously with Channel Status Information (CSI) information, and sending the modulated information to a base station by using the second pilot symbol of each slot of a plurality of orthogonal PUCCH resources. The present invention acquires a coding gain by the joint coding of the ACK/NACK information and makes the minimum Hamming distance extend, thereby enhancing the feedback quality of ACK/NACK.