Uplink MIMO HARQ Control Information Precoding
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Solution Overview
Problem
The legacy 3GPP LTE system lacks defined HARQ operations and control information methods for uplink multiple codeword transmission with multiple antennas, limiting efficient and correct support for uplink MIMO transmission.
Innovation Solution
A method for transmitting control information in wireless communication systems that includes scheduling multiple transport blocks through a physical downlink control channel, acknowledging or negating these blocks via a physical hybrid-automatic repeat request indicator channel, and using a specific precoding matrix for retransmissions based on the number of negative acknowledgments received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If HARQ operations are defined for uplink single codeword transmission only, then the system complexity remains low, but the system cannot support uplink MIMO transmission efficiently
Solution Approach 1:
The patent extends the HARQ operation framework to support both single codeword and multiple codeword transmissions through a unified mechanism. By defining通用的 HARQ processes that can handle different codeword configurations, the system achieves multi-functionality without requiring separate HARQ definitions for different transmission modes, thus resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The patent introduces dynamic selection of precoding matrices based on the number of transport blocks and HARQ feedback. The system can adaptively switch between different precoding configurations (e.g., 2x2 identity matrix for two blocks, 4x2 matrix for one block) depending on the transmission state, enabling efficient MIMO support while maintaining manageable complexity through conditional logic rather than fixed complex structures.
2Productivity
If multiple transport blocks are transmitted using multiple codewords, then the data transmission capacity increases, but the control information construction becomes more complex
Solution Approach 1:
The patent segments the control information construction into distinct components: transport block indication, HARQ feedback generation, and precoding matrix selection. Each component handles a specific aspect of the control information, making the overall construction process more manageable. The segmentation allows independent optimization of each component while maintaining their coordinated function for supporting multiple codeword transmissions.
Solution Approach 2:
The patent introduces precoding matrix indicators and PHICH resource indicators as intermediary elements that bridge the gap between multiple transport blocks and their corresponding HARQ feedback. These intermediaries simplify the control information construction by providing structured mapping relationships, reducing the complexity of directly managing multiple codewords and their feedback mechanisms.
3Reliability
If HARQ ACK/NACK signals are transmitted for each codeword, then the transmission reliability improves, but the control channel overhead increases
Solution Approach 1:
The patent merges multiple HARQ ACK/NACK signals into a unified PHICH resource indication mechanism. Instead of transmitting separate control signals for each codeword, the system combines the HARQ feedback information and precoding matrix information into a single integrated control structure. This merging reduces control channel overhead while maintaining the reliability of individual codeword acknowledgments through the unified feedback mechanism.
Data Source
AI summary
The present invention relates to a method for transmitting control information regarding uplink multiple antenna transmission may comprise the steps of: transmitting DCI for scheduling the uplink transmission of a plurality of data blocks through a PDCCH; receiving the plurality of data blocks scheduled by the DCI; transmitting information which indicates positive acknowledgement or negative acknowledgement to each of the plurality of received data blocks through the PHICH; and receiving retransmission for the negative acknowledged data blocks. When the number of the negative-acknowledged data blocks is not equal to the number data blocks indicated in the PDCCH, a pre-coding matrix, which is for the number of transmission layers equivalent to that of layers corresponding to the negative-acknowledged data blocks, may be used for retransmission.