Aperiodic SRS Resource Retention for Rapid Uplink CSI Acquisition
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Solution Overview
Problem
In LTE and LTE-A systems, there is a significant time delay in obtaining uplink channel state information (CSI) for the base station due to the need to reconfigure resources for periodic SRS after time-over or failed scheduling requests, and there is no effective method to utilize aperiodic SRS for rapid scheduling.
Innovation Solution
The method involves the user equipment (UE) not releasing preconfigured resources for aperiodic SRS transmission after time-over or failed scheduling requests, allowing it to transmit aperiodic SRS using these resources upon receiving indication from the base station, enabling rapid CSI acquisition and scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the base station reconfigures resources for periodic SRS after time-over or failed scheduling requests, then the uplink CSI can be obtained, but a significant time delay occurs
Solution Approach 1:
The UE maintains preconfigured aperiodic SRS resources in advance without releasing them after time-over or failed SR. When the base station needs uplink CSI, it can immediately trigger aperiodic SRS transmission using these pre-existing resources, eliminating the time delay associated with resource reconfiguration while ensuring accurate CSI measurement
2Productivity
If the UE releases periodic SRS resources after time-over or failed scheduling requests, then resource utilization is improved, but the base station cannot obtain uplink CSI rapidly
Solution Approach 1:
The system dynamically switches between periodic and aperiodic SRS modes. The UE maintains aperiodic SRS resources that can be activated on-demand via DCI triggering. When rapid CSI acquisition is needed, the base station triggers aperiodic SRS; otherwise, periodic SRS continues, optimizing both resource utilization and CSI acquisition speed based on actual network conditions
3Adaptability or versatility
If the base station uses DCI to trigger aperiodic SRS, then scheduling flexibility is enhanced, but the method is ineffective when UE has released SRS resources
Solution Approach 1:
The UE performs beforehand cushioning by maintaining aperiodic SRS resources in a ready state without releasing them after time-over or failed SR. This ensures that when the base station sends DCI triggering, the resources are already prepared and available, making the aperiodic SRS transmission reliable while preserving scheduling flexibility
Data Source
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Figure 2B~3
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AI summary
Disclosed are a method for triggering an aperiodic sounding reference symbol, a base station and a user equipment. The method comprises not releasing by a user equipment a resource used for transmitting an aperiodic sounding reference symbol configured by a base station for the user equipment, if the user equipment desynchronizes or the user equipment fails to transmit a scheduling request to the base station; executing a random access procedure by the user equipment; and transmitting by the user equipment the aperiodic sounding reference symbol on the unreleased resource used for transmitting an aperiodic sounding reference symbol configured by a base station for the user equipment according to indication information issued by the base station for indicating the user equipment to transmit an aperiodic sounding reference symbol if the random access succeeds. It is made possible through the embodiment that the base station rapidly obtains uplink channel state information (CSI) of the user equipment (UE) to thereby rapidly schedule transmission of uplink data of the user equipment (UE).