Aperiodic SRS Transmission on Unlicensed Spectrum
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Solution Overview
Problem
Existing terminal devices cannot send aperiodic SRS on a carrier of an unlicensed spectrum due to fixed symbol constraints, particularly in the LAA system, which hinders efficient communication.
Innovation Solution
An access network device sends specific indication information to a terminal device to instruct it to send an aperiodic SRS on a dynamically determined symbol within a subframe, allowing flexible allocation of symbols for SRS transmission based on channel assessment and system configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed symbols in a subframe are used to send aperiodic SRS, then the terminal device can send aperiodic SRS on predetermined symbols, but the terminal device cannot send aperiodic SRS when those fixed symbols are used to send downlink data or other uplink data
Solution Approach 1:
The patent applies dynamics by transitioning from fixed, predetermined symbol locations for aperiodic SRS transmission to dynamic, flexible symbol selection. The network device determines specific symbols within a first symbol set based on real-time channel conditions and resource availability, allowing the SRS transmission timing to adapt dynamically rather than being constrained by pre-configured fixed positions.
Solution Approach 2:
The patent changes the parameter of symbol location from fixed to variable. By introducing a first symbol set with multiple possible symbol positions and allowing the network device to select specific symbols based on current system state, the parameter of symbol location transforms from a static predetermined value to a dynamic selectable parameter that can be adjusted according to channel assessment and resource availability.
2Adaptability or versatility
If flexible symbol allocation is implemented for aperiodic SRS transmission, then terminal devices can send aperiodic SRS on unlicensed spectra, but requires additional indication information transmission from network device
Solution Approach 1:
The patent segments the symbol set into a first symbol set containing multiple candidate symbols, and further segments the indication information into compact fields that identify specific symbols within this set. This segmentation allows the system to manage the flexibility of symbol selection without requiring excessive indication information, as the indication only needs to specify which symbol from the predefined first symbol set should be used.
Solution Approach 2:
The first symbol set serves multiple functions: it provides candidate positions for aperiodic SRS transmission, enables flexible resource allocation, and works with the indication information to achieve both adaptability and efficient signaling. This multi-functional design allows the same symbol set structure to support various transmission scenarios without requiring separate mechanisms for each case.
Data Source
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AI summary
Embodiments of the present invention provide an aperiodic SRS transmission method and an apparatus, and relate to the communications field, so as to resolve a problem that an existing terminal device cannot send an aperiodic SRS on a carrier of an unlicensed spectrum. The transmission method includes: obtaining, by a terminal device, first indication information, where the first indication information is used to instruct the terminal device to send an aperiodic sounding reference signal SRS on a first symbol in a first subframe; and sending, by the terminal device, the aperiodic SRS on the first symbol based on the first indication information.