Aperiodic Reference Signal Slot Offsets for Uplink Beam Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently determining uplink precoders for non-codebook-based transmission due to insufficient time for beam switching when aperiodic downlink reference signals are triggered, leading to suboptimal beamforming configurations.
Innovation Solution
The implementation of a downlink reference signal resource slot offset and the use of Medium Access Control (MAC) control elements for dynamic configuration of downlink reference signal resources, allowing UEs to determine quasi co-location assumptions and adjust uplink beams more flexibly, even when aperiodic signals are triggered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aperiodic downlink reference signals are triggered with minimal slot offset, then system responsiveness and resource utilization are improved, but insufficient time is provided for UE beam switching and QCL determination
Solution Approach 1:
The base station configures multiple downlink reference signal resources in advance with different slot offsets, preparing multiple QCL assumptions beforehand. When an aperiodic reference signal is triggered, the UE can immediately use the pre-configured QCL assumption corresponding to the triggered resource, eliminating the need for real-time QCL determination and beam switching during the short slot offset period.
2Adaptability or versatility
If multiple downlink reference signal resources are configured with different slot offsets, then flexible beam switching and accurate QCL determination are enabled, but configuration complexity increases
Solution Approach 1:
Multiple downlink reference signal resources are configured with different slot offsets, where each resource serves as a universal template for QCL assumptions. The base station can trigger any of these pre-configured resources depending on the current beam switching state, making the configuration system universally applicable to different beam switching scenarios without requiring separate configurations for each case.
Solution Approach 2:
The system dynamically selects which downlink reference signal resource to trigger based on real-time beam switching requirements. The base station adjusts the triggering of specific reference signal resources according to the UE's beam switching capability and current state, enabling flexible adaptation without permanent configuration complexity for all possible scenarios.
3Measurement precision
If QCL assumption determination is performed in real-time, then accurate uplink precoder determination is achieved, but processing time and complexity increase
Solution Approach 1:
Multiple QCL assumptions are determined and configured in advance corresponding to different downlink reference signal resources with different slot offsets. The UE prepares multiple QCL assumptions beforehand, so when an aperiodic reference signal is triggered, the UE can immediately retrieve and use the appropriate pre-determined QCL assumption without performing real-time QCL determination, thus maintaining accuracy while reducing processing time.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive sounding reference signal (SRS) resource set configuration information that indicates an aperiodic SRS resource set, an aperiodic downlink reference signal resource associated with the aperiodic SRS resource set, and a slot offset associated with the aperiodic downlink reference signal resource. The UE may receive downlink control information indicating that the aperiodic SRS resource set is triggered and determine a quasi co-location assumption for the aperiodic downlink reference signal resource based on the slot offset associated with the aperiodic downlink reference signal resource. The UE may measure the aperiodic downlink reference signal resource in a slot indicated by the slot offset based on the quasi co-location assumption.