NR CSI Feedback Timing Offset for Flexible Subcarrier Spacing
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Solution Overview
Problem
The challenge in the New Radio (NR) system is to match its relatively high flexibility in communication with effective channel state information (CSI) feedback mechanisms, particularly in terms of timing and subcarrier spacing, which existing technologies have not adequately addressed.
Innovation Solution
The method involves sending first information in downlink control information (DCI) to trigger aperiodic or semi-persistent CSI reporting, determining the uplink time domain location based on a time offset and downlink time domain location, and receiving CSI in the specified uplink location, allowing for different time unit lengths for UL and DL transmissions, and potentially different subcarrier spacings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the NR system uses different time unit lengths for UL and DL transmissions to achieve flexibility, then the adaptability is improved, but the timing synchronization between UL and DL becomes more complex
Solution Approach 1:
The patent applies parameter changes by allowing different time unit lengths for UL and DL transmissions independently. The network device can configure different subcarrier spacings and time unit durations for uplink and downlink, enabling flexible adaptation to varying service requirements while maintaining proper timing relationships through configured offsets and mappings.
Solution Approach 2:
The patent introduces a timing offset parameter as an intermediary element that mediates the timing relationship between UL and DL transmissions with different time unit lengths. This offset acts as a bridge that allows the system to handle the complexity of asynchronous timing while maintaining synchronized operation at the protocol level.
2Adaptability or versatility
If the system allows different subcarrier spacings for UL and DL to improve adaptability, then the versatility is improved, but the scheduling complexity increases
Solution Approach 1:
The patent enables different subcarrier spacings for uplink and downlink by treating them as independent configurable parameters. The network device can select different subcarrier spacing values (e.g., 15 kHz for DL, 30 kHz for UL) based on service requirements, and the terminal adapts accordingly through configured mappings between DL and UL time domains.
3Productivity
If the terminal determines UL time domain location based on DL time domain location and time offset, then the scheduling flexibility is improved, but the calculation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the timing offset and time domain location mapping rules through RRC signaling or other higher-layer protocols. The terminal receives and stores these configuration parameters in advance, so that during actual operation, it only needs to perform simple calculations based on pre-established rules rather than complex real-time computations.
Data Source
AI summary
Implementations of the present application provide a wireless communication method and device, being able to match a relatively flexible NR system in terms of CSI feedback. The method comprises: sending first information, the first information being carried in downlink control information (DCI), the first information being used to trigger the terminal to report aperiodic channel state information (CSI) or to report semi-persistent CSI; determining a first uplink time-domain position according to a time offset and a first downlink time-domain position acting as a starting point, the time unit length of the time offset being a time unit length of uplink transmission for CSI reporting, or being a time unit length of downlink transmission performed on the first downlink time-domain position; receiving the CSI reported by the terminal at the first uplink time-domain position.