Base Station Feedback Timing Control for Unlicensed Band Efficiency
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Solution Overview
Problem
In wireless communication systems using unlicensed bands, the efficiency of HARQ (Hybrid Automatic Repeat Request) is decreased due to intermittent data transmission and increased LBT (Listen Before Talk) processes, caused by the overlap of feedback timing and burst transmission timing.
Innovation Solution
The proposed solution involves a base station device and a terminal device that manage feedback timing by including specific control information in the control channel. This control information designates feedback timing for the initial slots of a burst and collectively designates feedback for rearward slots with the next burst, minimizing the number of feedback transmissions and LBT processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback timing is designated for each slot in a burst transmission using unlicensed band, then HARQ accuracy is improved, but transmission efficiency deteriorates due to increased LBT processes and intermittent transmission
Solution Approach 1:
The patent merges feedback timing for multiple slots into a single common feedback timing. Instead of designating separate feedback timings for each slot in a burst transmission, the invention designates one common feedback timing that serves multiple slots, thereby reducing the number of LBT processes required and improving transmission efficiency while maintaining HARQ functionality
Solution Approach 2:
The invention makes the feedback timing universal across multiple slots by designating a common feedback timing that can serve feedback for multiple downlink slots. This multi-functional approach allows a single feedback timing to handle HARQ acknowledgments for multiple slots, reducing overhead and improving efficiency in unlicensed band communications
2Reliability
If LBT process is performed before each feedback transmission in unlicensed band, then channel access compliance is improved, but transmission continuity deteriorates due to frequent LBT interruptions
Solution Approach 1:
The patent combines multiple feedback transmissions into a single feedback opportunity by designating a common feedback timing. This merging approach reduces the number of separate LBT processes required, as fewer individual feedback transmissions need to be scheduled, thereby improving transmission continuity while maintaining compliance with unlicensed band access requirements
3Quantity of substance
If feedback timing overlaps with burst transmission timing, then resource utilization is improved, but transmission efficiency deteriorates due to suspended transmission
Solution Approach 1:
The invention performs preliminary action by designating a common feedback timing in advance that is specifically chosen to avoid overlap with burst transmission timing. This proactive scheduling ensures that feedback transmissions do not conflict with data transmissions, preventing suspended transmission and maintaining high transmission efficiency while effectively utilizing available resources
Data Source
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AI summary
A base station device (100) includes a data channel generating unit (122) that generates a data channel that is transmitted in each of one or more time units included in a first burst; a control channel generating unit (121) that generates a control channel that includes allocation information on the data channel included in the first burst and that includes control information that instructs to collectively feed back a decoding result related to the data channel together with a decoding result related to a second burst that is transmitted after the first burst; a LBT processing unit (140) that judges whether a frequency band for which a license is not needed to use in wireless communication is being used; and a wireless communicating unit (130) that transmits, when it is judged, by the LBT processing unit, that the frequency band is not being used, the first burst having the data channel and the control channel by using the frequency band.