Aperiodic SRS Trigger Offsets for Dynamic Slot Formats
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Solution Overview
Problem
Existing methods for triggering aperiodic sounding reference signals (SRS) lack flexibility due to fixed triggering offsets, leading to potential transmission issues when slot formats change dynamically.
Innovation Solution
Configuring multiple candidate triggering offsets for aperiodic SRS resource sets using RRC signaling and activating them with MAC CEs, allowing transmission in the first available slot that meets specific conditions, such as being a valid UL slot with no overlapping UL signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed triggering offset is configured for aperiodic SRS, then the configuration is simple, but the flexibility is limited when slot formats change dynamically
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed triggering offset to a dynamic selection mechanism. Multiple candidate triggering offsets are configured, and the UE dynamically selects the appropriate offset based on the current slot format indicated by DCI format 2_0. This allows the SRS transmission to adapt to changing slot formats while maintaining a manageable configuration structure.
Solution Approach 2:
The patent changes the parameter of triggering offset from a fixed value to a selectable set of candidate values. The UE determines which candidate offset to use based on the indicated slot format, effectively changing the offset parameter dynamically rather than being fixed, thereby resolving the contradiction between flexibility and complexity.
2Reliability
If a triggering offset is configured for aperiodic SRS, then the SRS can be transmitted, but the transmission may fail when the indicated slot is not a valid UL slot or has conflicting UL signals
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple candidate triggering offsets that are sorted in ascending order. The UE prepares these candidate offsets in advance and uses them to determine the appropriate transmission slot based on the indicated slot format, ensuring reliable transmission before the actual SRS transmission occurs.
Solution Approach 2:
The patent implements feedback by having the UE determine the triggering offset based on the slot format indication received in DCI format 2_0. The UE uses this feedback information (slot format indication) to select the appropriate candidate offset, ensuring the SRS is transmitted in a valid UL slot without conflicts, thereby improving reliability.
3Reliability
If multiple candidate triggering offsets are configured and selected based on slot format, then the flexibility and reliability are improved, but the complexity of determining the correct offset increases
Solution Approach 1:
The patent applies preliminary action by pre-sorting the candidate triggering offsets in ascending order and pre-determining which offsets correspond to valid UL slots. This preparation eliminates the need for complex real-time determination, as the UE simply needs to select from the pre-organized candidate list based on the slot format indication.
Solution Approach 2:
The patent segments the candidate triggering offsets into different categories based on their validity for UL transmission. By dividing the offsets into valid and invalid categories and organizing them in a sorted list, the UE can easily determine the correct offset without complex measurement or detection, reducing the difficulty while maintaining high reliability.
Data Source
AI summary
Methods and apparatuses for triggering an aperiodic SRS are disclosed. A method comprises receiving a RRC signaling configuring N triggering offsets for each of P aperiodic SRS resource sets, where N is 1 or more, P is 1 or more; receiving a MAC CE to activate one or more triggering offset(s) among all configured triggering offsets for each of M out of the P aperiodic SRS resource sets, where M is 1 to P; receiving a DCI containing a non-zero SRS request field triggering at least one aperiodic SRS resource set, wherein at least one triggering offset of each triggered aperiodic SRS resource set is activated by the MAC CE; and transmitting SRS resources contained in each triggered aperiodic SRS resource set in the first available slot among all candidate slots indicated by the activated triggering offsets for each triggered aperiodic SRS resource set.