CSI and HARQ Feedback Timing for Faster 5G NR Link Adaptation
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Solution Overview
Problem
Existing 5G NR communication systems face challenges in efficiently adapting modulation and coding schemes, code rate, and transmission power due to the lack of timely and accurate channel state information (CSI) reporting, particularly in conjunction with hybrid automatic repeat request (HARQ) feedback.
Innovation Solution
The method enables a user equipment (UE) to determine whether to report CSI together with HARQ feedback, and a base station to indicate and receive this combined feedback, allowing for faster and more accurate adaptation of MCS, code rate, and transmission power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CSI reporting is enabled separately from HARQ feedback, then channel state information can be obtained, but the adaptation speed of MCS and code rate is delayed
Solution Approach 1:
The patent combines CSI reporting with HARQ feedback transmission by multiplexing the CSI report and HARQ feedback into a single uplink signal. This merging allows the base station to receive both channel state information and acknowledgment signals simultaneously, eliminating the time delay between obtaining CSI and using it for MCS adaptation, thus resolving the contradiction between measurement precision and adaptation speed.
Solution Approach 2:
The patent enables the UE to prepare and transmit CSI reports in advance of actual data transmission needs. By configuring the UE to report CSI at predetermined intervals or upon trigger events before the base station needs to adapt MCS, the system performs preliminary action that allows faster subsequent adaptation without waiting for real-time CSI measurement.
2Loss of information
If separate CSI reporting is implemented, then channel state information is available, but transmission latency increases
Solution Approach 1:
The patent merges CSI reporting with HARQ feedback transmission, allowing both information types to be conveyed in a single uplink transmission opportunity. This eliminates the sequential transmission process where CSI is sent separately before or after data, thereby reducing overall transmission latency while maintaining complete information flow.
Solution Approach 2:
The patent establishes continuous feedback loops where CSI reporting is integrated into the existing HARQ feedback timing. This ensures that channel state information is continuously available to the base station without interrupting the data transmission flow, maintaining continuous useful action and preventing latency accumulation.
3Measurement precision
If CSI reporting timing is extended, then more accurate channel measurement is possible, but adaptation responsiveness decreases
Solution Approach 1:
The patent configures the UE to perform channel measurement and CSI report preparation in advance based on predicted transmission conditions. By performing preliminary action at optimal measurement moments rather than waiting for real-time needs, the system achieves both high measurement precision and rapid subsequent adaptation responsiveness.
Solution Approach 2:
The patent implements dynamic adjustment of CSI reporting timing based on actual transmission conditions. The system can flexibly adjust when CSI measurement and reporting occur to match the base station's adaptation needs, allowing optimal measurement precision at the right moment without fixed delays that would reduce responsiveness.
Data Source
AI summary
A user equipment (UE) receives downlink communication that triggers a channel state information (CSI) report. Then the UE determines whether to report CSI together with hybrid automatic repeat request (HARQ) feedback. Then the UE transmits the CSI and the HARQ feedback based on the determining whether to report the CSI together with the HARQ feedback.