Unified Feedback for Configured Grant in Unlicensed Spectrum
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Solution Overview
Problem
Current wireless communication systems face challenges in providing unified feedback for configured grants in ultra-reliable communication and unlicensed spectrum, leading to misinterpretation of HARQ feedback and potential degradation of communication quality.
Innovation Solution
A method where a user equipment (UE) starts a timer after transmitting an uplink communication on a physical uplink shared channel using a configured grant, and determines acknowledgement based on the detection of a downlink communication within the associated time duration, while the base station sets an indication for a certain acknowledgement mode based on the presence of a hidden node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE waits for explicit HARQ feedback from the base station, then the feedback accuracy is improved, but the communication latency increases and retransmission efficiency decreases
Solution Approach 1:
Instead of waiting for explicit feedback to determine transmission success, the patent inverts the logic by assuming transmission success based on the absence of feedback (negative feedback implication). This allows the UE to proceed with retransmission decisions without waiting for explicit confirmation, reducing latency while maintaining reliability through the timer-based feedback window mechanism.
Solution Approach 2:
The patent implements a feedback mechanism where the base station's silence within a timer duration is interpreted as negative feedback. This feedback approach allows the UE to infer transmission status without explicit signaling, resolving the contradiction by making the feedback implicit rather than explicit, thus reducing waiting time while maintaining accuracy.
2Reliability
If the UE performs frequent retransmissions to ensure reliability, then the communication reliability is improved, but the resource consumption increases
Solution Approach 1:
The timer-based feedback mechanism provides accurate information about transmission success, allowing the UE to make informed retransmission decisions. By using the absence of feedback within the timer duration as a reliable indicator of successful transmission, the system can avoid unnecessary retransmissions, thereby reducing energy consumption while maintaining communication reliability.
Solution Approach 2:
The patent changes the feedback parameter from explicit acknowledgment signals to a time-based implicit feedback mechanism. By using the timer duration as the feedback parameter, the system can determine transmission success without additional signaling, reducing resource consumption while maintaining the ability to perform reliable retransmissions when needed.
3Productivity
If the base station transmits downlink communication immediately, then the downlink throughput is improved, but the uplink feedback accuracy deteriorates
Solution Approach 1:
The base station transmits downlink communication before the timer expires, which is the preliminary action that enables both high downlink throughput and accurate uplink feedback. The timer is configured to expire after the expected downlink transmission time, allowing the base station to send downlink data immediately while ensuring the timer provides sufficient time for accurate feedback determination.
Solution Approach 2:
The patent adjusts the timer duration parameter to match the expected downlink transmission time. By setting the timer to expire at the appropriate time, the system can allow immediate downlink transmission while maintaining feedback accuracy, as the timer provides the precise time window needed to distinguish between successful transmission and transmission failure.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may start a timer after transmitting an uplink communication on a physical uplink shared channel to a base station using a configured grant. The UE may determine whether the uplink communication is acknowledged as received by the base station based at least in part on determining whether a downlink communication from the base station is detected within a time duration associated with the timer. Numerous other aspects are provided.