Dynamic SRS Scheduling for mmWave Channel Estimation
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Solution Overview
Problem
Current wireless communication systems face challenges in dynamically adjusting sounding reference signal (SRS) parameters for efficient channel estimation and data transmission, particularly in millimeter wave frequencies, due to increased path loss and the need for flexible scheduling of UEs, which often results in costly and inflexible pre-configuration of SRS parameters by upper layers.
Innovation Solution
A method and apparatus for dynamic SRS scheduling, where a base station identifies an SRS configuration for a user equipment (UE) and transmits an SRS grant message with indicated parameters, allowing the UE to autonomously adjust SRS transmissions based on channel conditions or environment measurements, enabling flexible scheduling and improved resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SRS parameters are pre-configured by upper layers, then system reliability is maintained, but scheduling flexibility and adaptability deteriorate
Solution Approach 1:
The patent implements dynamic SRS parameter adjustment by introducing a physical layer mechanism that allows real-time modification of pre-configured parameters. The base station can dynamically indicate SRS transmission parameters through physical downlink control channel (PDCCH) messages, enabling the system to adapt to changing channel conditions and scheduling requirements while maintaining a fallback to pre-configured values for stability.
Solution Approach 2:
The patent changes the state of SRS parameters from static pre-configured values to dynamically adjustable parameters. By introducing a physical layer indication mechanism, the system can modify SRS transmission parameters such as frequency position, time position, and cyclic shift based on current channel conditions and scheduling needs, resolving the contradiction between adaptability and reliability.
2Productivity
If SRS parameters are dynamically adjusted, then scheduling flexibility improves, but system complexity and signaling overhead increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring SRS parameter sets at the upper layer before dynamic adjustment is needed. These pre-configured parameter sets serve as a foundation that reduces the complexity of real-time adjustments, as the physical layer only needs to indicate selections from pre-defined options rather than managing all parameters from scratch.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of physical layer indication messages that mediate between the pre-configured parameters and the actual SRS transmission. This intermediary layer simplifies the complexity by providing a standardized interface for parameter adjustment, where the base station sends concise indication messages rather than managing complex parameter sets directly.
3Adaptability or versatility
If multiple DCI formats indicate different SRS parameters, then scheduling adaptability improves, but parameter consistency and reliability deteriorate
Solution Approach 1:
The patent applies inversion by reversing the traditional approach to parameter indication. Instead of allowing multiple DCI formats to independently indicate parameters and hoping for consistency, the system inverts the logic by establishing a hierarchy where the first received indication takes precedence and subsequent indications are ignored if they contradict, thus ensuring parameter consistency while maintaining adaptability.
Solution Approach 2:
The patent applies preliminary anti-action by preemptively preventing parameter contradictions through a rule that ignores subsequent DCI indications when a previous indication has already been received. This preliminary protective measure avoids the harmful effect of parameter inconsistency before it can occur, ensuring reliable SRS transmission even when multiple DCI formats are involved.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described. A base station may identify a sounding reference signal (SRS) configuration for user equipment (UE). The base station may transmit an SRS grant message to a UE indicating the SRS configuration. An indication of SRS parameters may be included in the SRS grant message, and may include the SRS parameters or a location of the SRS parameters. That is, SRS parameters may be transmitted in a control channel with the SRS grant message or may be separately sent in a data channel as indicated by the indication of SRS parameters. In some cases, SRS parameters may be determined based on previously received UE feedback regarding channel conditions or power limitations. Alternatively, the base station may make its own environment measurements or assign SRS parameters autonomously. The UE may signal SRS transmissions to the base station according to the SRS grant message.