Deferred HARQ Feedback Handling During Carrier Switching
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Solution Overview
Problem
In wireless communication systems, collisions between downlink and uplink communications due to slot format changes in time division duplexing configurations lead to deferred hybrid automatic repeat request (HARQ) feedback issues, which cannot be transmitted on the second component carrier due to resource unavailability or insufficiency, causing complexity and reliability problems.
Innovation Solution
Implementing methods and apparatuses that enable dropping, deferring, or processing HARQ feedback in various communication scenarios, including carrier switching, to manage deferred HARQ feedback effectively, reducing hardware and memory requirements and increasing communication reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carrier switching is implemented to transmit deferred HARQ feedback on a second component carrier, then HARQ feedback transmission capability is improved, but device complexity and memory requirements increase due to the need to manage and buffer deferred feedback across multiple carriers
Solution Approach 1:
The patent extracts the deferred HARQ feedback from the buffer memory and directly transmits it on the second component carrier when resources are available. This eliminates the need to maintain complex buffer structures for deferred feedback across multiple carriers, reducing UE complexity while preserving the ability to transmit deferred feedback reliably.
Solution Approach 2:
The patent implements dynamic carrier switching based on the availability of uplink resources on the second component carrier. The UE dynamically decides whether to switch carriers for deferred HARQ feedback transmission or drop the feedback based on current resource conditions, optimizing the balance between reliability and complexity.
2Reliability
If deferred HARQ feedback is transmitted on a second component carrier, then feedback coverage is improved, but resource availability and uplink capacity are reduced due to the deferred feedback occupying uplink resources
Solution Approach 1:
The patent applies partial action by selectively transmitting only the necessary HARQ feedback on the second component carrier when resources are available, rather than always transmitting all deferred feedback. This partial transmission approach ensures critical feedback is delivered while minimizing the occupation of uplink resources.
Solution Approach 2:
The patent implements a discard mechanism for deferred HARQ feedback when uplink resources on the second component carrier are insufficient. By discarding deferred feedback that cannot be transmitted, the system recovers uplink resource capacity for other critical communications, maintaining overall system efficiency.
3Adaptability or versatility
If carrier switching is performed for deferred HARQ feedback, then communication flexibility is improved, but time synchronization and resource coordination become more difficult
Solution Approach 1:
The patent performs preliminary carrier switching before the uplink resource allocation for deferred HARQ feedback transmission. By switching carriers in advance and preparing the transmission buffer beforehand, the system minimizes time synchronization overhead and ensures seamless transition to the second component carrier when resources become available.
Data Source
AI summary
This disclosure provides systems, methods, and apparatuses for deferred hybrid automatic repeat request (HARQ) feedback for carrier switching. Some aspects described herein enable a user equipment (UE) to transmit, drop, refrain from transmitting, or a combination thereof, deferred HARQ feedback in various communication scenarios that involve the use of carrier switching. The UE is enabled to continue to defer deferred HARQ feedback, to drop deferred HARQ feedback, to transmit non-deferred HARQ feedback, to drop all HARQ feedback, or to process deferred HARQ feedback using another technique described herein where carrier switching is configured for the UE.