Uplink Feedback for PUSCH in LTE TDD Special Subframes
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Solution Overview
Problem
There is a lack of solutions for transmitting ACK/NACK feedback information of an uplink shared channel transmitted in an UpPTS (Uplink Pilot Time Slot) in the LTE TDD system, which hinders efficient uplink transmission in special subframes.
Innovation Solution
A method and device for transmitting feedback information, where a terminal transmits a Physical Uplink Shared Channel (PUSCH) in a special subframe and detects a downlink control channel with an uplink DCI format in a subsequent subframe or subframe k, determining whether to retransmit based on an indicating field in the downlink control channel, using various schemes such as DCI size, indicating fields, RNTI, and UL index to identify the PUSCH transmission in a special subframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PUSCH is transmitted in UpPTS of special subframe, then uplink transmission capacity is improved, but feedback information transmission mechanism is lacking
Solution Approach 1:
The patent uses the downlink control channel as an intermediary to convey feedback information. Instead of creating a separate feedback channel, the invention repurposes the existing downlink control channel structure to carry ACK/NACK information for UpPTS transmissions, thereby solving the feedback information transmission problem without adding new channel structures.
Solution Approach 2:
The downlink control channel is given multi-functionality by making it serve both its traditional purpose of carrying scheduling information and the new function of carrying feedback information for UpPTS transmissions. This is achieved by utilizing the NDI field and other existing control channel elements to convey acknowledgment information, thus eliminating the need for dedicated feedback resources.
2Loss of information
If feedback information is transmitted in downlink control channel, then feedback mechanism is established, but identification of PUSCH transmission location becomes complex
Solution Approach 1:
The patent applies local quality by making the downlink control channel format specific to UpPTS feedback. The control channel includes specific fields (such as NDI, HARQ process number, and uplink index) that are locally optimized to identify and convey feedback for UpPTS transmissions, distinguishing it from other downlink control channel uses and simplifying identification at the receiver.
Solution Approach 2:
The invention changes parameters of the downlink control channel to enable feedback transmission. Specifically, it modifies the interpretation of existing fields (like NDI and uplink index) and adds specific parameter combinations that indicate UpPTS feedback, allowing the receiver to identify the feedback nature and corresponding PUSCH transmission location through parameter analysis rather than complex structural changes.
3Measurement precision
If multiple indication schemes are used to identify PUSCH in special subframe, then feedback accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent merges multiple indication functions into a single downlink control channel message. By combining the NDI field, HARQ process number, uplink index, and other parameters into one integrated control channel transmission, the invention achieves accurate PUSCH identification and feedback delivery without requiring separate signaling messages for each parameter, thus reducing overall signaling overhead while maintaining high identification accuracy.
Data Source
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AI summary
The present invention discloses a transmission method and apparatus for feedback information of uplink transmission. The method comprises: a terminal transmitting a physical uplink shared channel (PUSCH) in a special sub-frame m, where m is an integer; the terminal detecting, subsequent to the special frame m, in a sub-frame comprising downlink transmission resources or in a sub-frame m+k, a downlink control channel using an uplink/downlink control information (DCI) format, where k is a positive integer; and the terminal determining, according to the downlink control channel, whether to again transmit the PUSCH transmitted in the special sub-frame m. accordingly, the present invention provides a transmission solution that transmits PUSCH feedback information in a special sub-frame, ensuring that the PUSCH transmitted in the special sub-frame can normally obtain ACK/NACK feedback information.