SRS Configuration via Joint DCI Indication
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Solution Overview
Problem
In LTE-A systems, accurately and flexibly indicating sounding reference signal (SRS) configurations to terminals is challenging due to the large amount of information and limited resources of the physical downlink control channel (PDCCH), leading to potential confusion when multiple DCI messages contain SRS configuration information.
Innovation Solution
Generating and transmitting at least two pieces of downlink control signaling DCI, each including SRS configuration information elements, to jointly indicate an SRS configuration, allowing for coordinated and unified indication of SRS parameters such as transmission time, frequency domain position, bandwidth, and antenna ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple DCI messages are used to indicate SRS configuration information, then the flexibility and accuracy of SRS configuration indication is improved, but the confusion and complexity in processing multiple DCI messages increases
Solution Approach 1:
The terminal feeds back the subframe index where SRS is transmitted to the base station. This feedback mechanism allows the base station to confirm which DCI message successfully triggered the SRS transmission, resolving ambiguity when multiple DCI messages are present. The feedback loop enables the system to maintain high configuration indication accuracy while managing the complexity of multiple DCI messages through explicit confirmation.
2Speed
If SRS configuration information is delivered through PDCCH, then the real-time control capability is improved, but the overhead of PDCCH increases
Solution Approach 1:
The SRS configuration information is segmented into two parts: semi-static parameters (transmission time, frequency domain position, bandwidth, hopping bandwidth) are delivered through higher layer signaling (RRC), while dynamic parameters (trigger information, cyclic shift, comb) are delivered through PDCCH. This segmentation reduces PDCCH overhead by moving bulk configuration data to higher layers, while retaining real-time control capability for dynamic parameters through PDCCH.
3Adaptability or versatility
If multiple DCI messages with SRS configuration information elements are transmitted in a subframe, then the flexibility of SRS configuration is improved, but the confusion in triggering SRS transmission increases
Solution Approach 1:
The terminal performs preliminary actions by monitoring and comparing multiple DCI messages before triggering SRS transmission. The terminal applies priority rules to determine which DCI message takes precedence when multiple messages with SRS configuration information elements are received in the same subframe. This preliminary decision-making process ensures reliable SRS triggering by establishing clear selection criteria before transmission occurs.
Solution Approach 2:
The terminal provides feedback about which DCI message triggered the SRS transmission by feeding back the subframe index to the base station. This feedback mechanism resolves confusion by allowing the base station to identify which specific DCI message successfully triggered the SRS, enabling reliable configuration interpretation even when multiple DCI messages are present.
Data Source
AI summary
A method for transmitting a sounding reference signal and a method and device for indicating a configuration are provided. A method for indicating a sounding reference signal configuration may include: generating at least two pieces of downlink control signaling DCI, where each of the at least two pieces of DCI includes a sounding reference signal SRS configuration information element; and transmitting the at least two pieces of DCI in a subframe to a terminal, so that the SRS configuration information elements in the at least two pieces of DCI are used to jointly indicate an SRS configuration. Solutions of embodiments of the present invention can improve accuracy and flexibility of indicating an SRS configuration.