Aperiodic SRS Configuration via Higher Layer Signaling
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Solution Overview
Problem
Existing methods for configuring aperiodic SRS in LTE-A systems lead to increased resource consumption on the Physical Downlink Control Channel (PDCCH) and inefficiencies in resource allocation, especially with multiple activated users, due to the need for specific DCI formats and high bit usage.
Innovation Solution
Implementing semi-static configuration of aperiodic SRS through higher layer signaling, allowing flexible sub-frame and frequency domain configurations, and enabling aperiodic SRS transmission in multiple sub-frames to reduce system delay and increase detection bandwidth, while maintaining flexible timing without excessive scheduling limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SRS-specific DCI format is introduced for aperiodic SRS configuration, then dynamic resource configuration capability is improved, but PDCCH resource consumption increases significantly
Solution Approach 1:
The patent merges the aperiodic SRS configuration functionality into existing DCI formats (DCI format 0/1A for aperiodic SRS, DCI format 4 for periodic SRS) rather than creating a separate dedicated format. This combining approach allows the base station to configure aperiodic SRS resources using the same control channel structures already in use for other uplink grants, thereby avoiding additional PDCCH resource consumption while maintaining dynamic configuration capability.
Solution Approach 2:
The DCI formats are designed to serve multiple functions: they can carry both periodic SRS configuration (via DCI format 4) and aperiodic SRS configuration (via DCI format 0/1A with specific flags). This multi-functionality allows a single control signal structure to handle different SRS configuration needs, reducing the overall control channel overhead while providing adaptable resource allocation.
2Adaptability or versatility
If multiple activated users are supported with aperiodic SRS, then system flexibility is improved, but resource consumption on PDCCH becomes excessive
Solution Approach 1:
By merging aperiodic SRS configuration into existing DCI formats that are already used for uplink grants, the patent enables multiple users to be served without requiring separate dedicated control formats for each user's SRS configuration. The same DCI structure can be reused across multiple users, reducing the cumulative control overhead while maintaining the ability to flexibly activate SRS for different users.
3Reliability
If periodic SRS is used with long dispatching cycle, then uplink channel sounding is achieved, but physical resource consumption increases
Solution Approach 1:
The patent introduces dynamic activation and deactivation mechanisms for aperiodic SRS through DCI formatting, allowing the base station to flexibly control when SRS transmission occurs based on actual channel conditions and scheduling needs. This dynamic approach replaces the fixed periodic transmission pattern, enabling the system to activate SRS only when needed for channel sounding while avoiding continuous resource consumption during periods when channel conditions are stable or data transmission is not required.
Solution Approach 2:
While aperiodic SRS is activated dynamically, the system maintains the ability to perform periodic channel sounding when needed through the aperiodic mechanism. The base station can trigger multiple aperiodic SRS transmissions in sequence if continuous channel monitoring is required, effectively achieving periodic sounding behavior without the resource consumption of true periodic configuration.
Data Source
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AI summary
Embodiments of the present invention disclose a transmission method and device for aperiodic Sounding Reference Signal (SRS). By applying the technical solution of the embodiments in the present invention, a Base Station (BS) performing semi-static configuration of the aperiodic SRS on a mobile terminal through higher layer signaling to decrease signaling overhead. On the one hand, different sub-frames can be set with different or the same Cycle Shift (CS) and resource positions to increase the flexibility of system setting; On the other hand, aperiodic SRS may be transmitted in a plurality of sub-frames to reduce system delay and increase detection bandwidth. Moreover, the relatively flexible timing mode can be set in the terminal without bringing too many limits on the scheduling.