SRS Transmission Across Multiple Slots for Uplink Beam Refinement
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Solution Overview
Problem
In wireless communication systems, especially above 6GHz, channel conditions change rapidly due to additional channel elements, leading to Tx/Rx beam mismatch during beam scanning, which is inefficient and resource-intensive, and existing methods struggle to adaptively manage SRS transmission for uplink beam refinement.
Innovation Solution
A method for a user equipment (UE) to receive control information for SRS transmission across multiple slots or subframes, allowing flexible SRS mapping and transmission based on available resources, including uplink transmission beams and ports, to accommodate the dynamic channel conditions and beam configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beam scanning is performed with short periodicity to track rapid channel changes above 6GHz, then beam tracking accuracy is improved, but processing overhead increases and resource consumption increases
Solution Approach 1:
The patent segments the beam tracking process into two distinct phases: beam scanning (for initial acquisition) and beam refinement (for continuous tracking). This segmentation allows the system to use resource-intensive beam scanning only when necessary (e.g., when beam mismatch is detected), while using lighter beam refinement operations for continuous tracking, thereby reducing overall processing overhead while maintaining tracking accuracy.
Solution Approach 2:
The patent implements periodic beam scanning with configurable intervals rather than continuous scanning. The beam scanning periodicity can be adjusted based on channel conditions, allowing the system to balance between tracking accuracy and resource consumption. During periods of stable channel conditions, scanning can be performed less frequently, reducing overhead while maintaining adequate tracking performance.
2Measurement precision
If the number of SRS transmission beams is increased to cover all uplink transmission beams, then beam refinement accuracy is improved, but resource requirements exceed available slots or subframes
Solution Approach 1:
The patent segments the set of uplink transmission beams into multiple subsets, where each subset contains a manageable number of beams that can be tested within available SRS resources. This segmentation allows comprehensive beam refinement across all beams over multiple SRS transmission occasions, rather than requiring all beams to be tested simultaneously in a single slot or subframe.
Solution Approach 2:
The patent allows the SRS to transmit more beams than can be accommodated in a single slot or subframe by utilizing multiple SRS transmission occasions. This partial action approach tests a subset of beams in each occasion, and the process is repeated across multiple occasions to cover all beams, effectively performing the refinement in stages rather than requiring excessive resources in a single occasion.
3Loss of energy
If beam scanning periodicity is extended to reduce processing overhead, then resource consumption is reduced, but beam tracking becomes insufficient for rapidly changing channels
Solution Approach 1:
The patent employs feedback mechanisms where the base station evaluates SRS measurements and determines whether beam mismatch has occurred. Based on this feedback, the base station can dynamically adjust the beam scanning periodicity - increasing it when beam mismatch is detected (improving reliability) and decreasing it when conditions are stable (reducing overhead). This adaptive feedback-based periodicity adjustment resolves the contradiction between overhead reduction and tracking reliability.
Solution Approach 2:
The patent makes the beam scanning periodicity dynamic rather than fixed. The periodicity can be adjusted based on channel conditions, terminal behavior patterns, and beam tracking performance. This dynamic adjustment allows the system to respond to rapidly changing channels by shortening periodicity when needed while maintaining long periodicity during stable conditions, thereby balancing reliability and overhead.
4Adaptability or versatility
If SRS transmission is configured for all uplink beams simultaneously, then comprehensive beam coverage is achieved, but resource allocation becomes infeasible within single slot or subframe
Solution Approach 1:
The patent segments the SRS transmission configuration into multiple manageable units corresponding to different beam subsets and multiple time occasions. This segmentation transforms the infeasible problem of configuring all beams simultaneously into a series of feasible configurations, where each SRS transmission occasion handles a subset of beams with straightforward resource allocation.
Data Source
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AI summary
A method by which a terminal transmits an SRS comprises the steps of: receiving, from a base station, control information indicating a transmission request of SRS in a plurality of slots or subframes; and transmitting SRSs in the plurality of slots or subframes on the basis of the control information, wherein the control information can be received when the total number of uplink transmission beams or the number of ports for SRS transmission exceeds the maximum number of SRS beams, which can be transmitted in one slot or one subframe, or the number of ports for SRS transmission.