PSFCH Cyclic Shift Configuration for Reliable V2X HARQ Feedback
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Solution Overview
Problem
Existing LTE V2X communication primarily supports broadcast communication and lacks efficient mechanisms for unicast and groupcast communication, particularly in out-of-coverage scenarios, necessitating improved HARQ feedback methods for enhanced reliability and spectrum efficiency in 5G NR network technologies.
Innovation Solution
A method for user equipment involving the transmission of a physical sidelink feedback channel (PSFCH) with a generated cyclic shift of a sequence, determined by a parameter cinit, to carry HARQ feedback information, enhancing HARQ feedback mechanisms for unicast and groupcast communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LTE V2X communication uses broadcast communication mode, then coverage is achieved, but reliability and spectrum efficiency are insufficient for unicast and groupcast scenarios
Solution Approach 1:
The patent segments the feedback channel into multiple subchannels, where each subchannel carries feedback information for a specific group of UEs. This segmentation enables the system to simultaneously support broadcast, unicast, and groupcast communication modes by selectively activating different subchannels, thereby improving reliability while maintaining adaptability across various communication scenarios
Solution Approach 2:
The patent introduces a new dimension to the feedback mechanism by utilizing frequency hopping across multiple subchannels. Instead of a single feedback channel, the system employs multiple subchannels that hop in frequency, enabling simultaneous transmission of feedback for different UE groups. This dimensional expansion allows the system to achieve both high reliability through diverse transmission paths and versatility across communication modes
2Adaptability or versatility
If out-of-coverage D2D communication is implemented, then direct communication is enabled, but HARQ feedback mechanism is insufficient for ensuring reliability
Solution Approach 1:
The patent implements a feedback mechanism where receiving UEs transmit HARQ feedback information on dedicated feedback resources back to transmitting UEs. This feedback loop is crucial for out-of-coverage D2D communication as it enables reliability enhancement without network involvement. The feedback carries ACK/NACK indications that allow transmitting UEs to determine whether retransmission is needed, directly addressing the reliability challenge in autonomous D2D scenarios
Solution Approach 2:
The patent enables self-service operation in out-of-coverage scenarios by allowing UEs to autonomously manage their own communication reliability through local HARQ feedback processing. Each UE independently determines feedback transmission timing and content based on received data, eliminating dependency on base station control while maintaining communication reliability through distributed feedback coordination
3Productivity
If multiple subchannels are introduced for feedback transmission, then spectrum efficiency is improved, but device complexity increases
Solution Approach 1:
The patent employs periodic feedback transmission where UEs send HARQ feedback at predetermined time intervals rather than continuously. The feedback is transmitted in periodic slots following a defined timing pattern, which simplifies the scheduling complexity while maintaining high spectrum efficiency. This periodic approach allows the system to achieve productive use of spectral resources without requiring complex real-time scheduling algorithms
Data Source
AI summary
Provided in the present invention are a method performed by user equipment and user equipment. The method comprises: determining sidelink resource pool configuration information; receiving a PSCCH and a corresponding PSSCH transmitted by another user equipment; and determining an initialization sequence parameter cinit of a cyclic shift α1 of a sequence for a physical sidelink feedback channel (PSFCH).