HARQ Feedback Handling During Measurement Gaps
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Solution Overview
Problem
In mobile communication systems, particularly in LTE, the overlap of measurement gaps with HARQ feedback information reception timing causes disruptions in HARQ operations, leading to inefficiencies and potential disconnections in data transmission.
Innovation Solution
A method where terminals determine and set HARQ feedback information to acknowledgement or non-acknowledgement based on the presence of a measurement gap, allowing for continued HARQ operations by keeping signals in a buffer and retransmitting when possible, thereby avoiding the need for precise feedback timing alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement gap is configured for terminal to perform measurements, then measurement capability is improved, but HARQ feedback reception reliability deteriorates when timing overlaps
Solution Approach 1:
The terminal determines in advance whether a measurement gap overlaps with the HARQ feedback reception timing point before attempting to receive feedback. This preliminary check allows the terminal to proactively handle the potential conflict by self-determining the feedback status, ensuring that HARQ operations continue without disruption even when measurement activities are performed.
2Duration of action of stationary object
If terminal self-determines HARQ feedback status, then HARQ operation continuity is improved, but system complexity increases
Solution Approach 1:
The terminal autonomously determines its own HARQ feedback status by checking whether a measurement gap overlaps with the feedback reception timing. This self-service approach eliminates the need for complex coordination with the base station, as the terminal independently resolves the timing conflict and continues HARQ operations without external intervention, thereby maintaining operational continuity while keeping the added complexity minimal.
3Device complexity
If HARQ feedback timing is fixed, then system simplicity is improved, but adaptability to measurement gaps deteriorates
Solution Approach 1:
While maintaining fixed HARQ feedback timing for system simplicity, the terminal dynamically adapts by determining whether a measurement gap overlaps with the predetermined feedback timing. When overlap is detected, the terminal self-determines the feedback status and adjusts its HARQ operations accordingly. This dynamic adaptation allows the system to handle measurement gap scenarios without changing the overall fixed timing structure, thereby preserving system simplicity while gaining flexibility.
Data Source
AI summary
A HARQ processing method is disclosed, by which a measurement gap is considered. In particular, as a terminal performs an inter-measurement operation, if HARQ feedback information reception is impossible, the terminal determines HARQ feedback information, which is not received for a next HARQ operation, as ACK or NACK by itself and is then able to perform the next HARQ operation. Specifically, in case that the terminal operates by determining the non-received HARQ feedback information as ACK, a corresponding uplink signal keeps being stored in an HARQ buffer and can be retransmitted according to a new UL grant reception from a base station.