SRS Scheduling via Physical Indication Signal in Unlicensed Spectrum

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Solution Overview

Problem

In Licensed Assisted Access (LAA) systems, sending a sounding reference signal (SRS) in unlicensed spectra is challenging due to shared resource occupancy by multiple systems, leading to incorrect channel state estimation and inflexible triggering mechanisms for user equipment that does not need to transmit data frequently.

Innovation Solution

A method and apparatus that determine an available carrier in an unlicensed spectrum and send a physical indication signal with SRS scheduling information, allowing user equipment to flexibly send SRS based on received scheduling information, even for equipment not scheduled for data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional SRS triggering using scheduling signaling is used in LAA systems, then user equipment scheduled for data transmission can send SRS, but user equipment not scheduled for data transmission cannot send SRS, resulting in inability to obtain channel state for all user equipment

Engineering Contradiction:

ImproveSRS triggering flexibilityVSAvoidchannel state information

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies universality by using a common physical indication signal mechanism that serves multiple purposes: it can trigger SRS for user equipment scheduled for data transmission, and simultaneously trigger SRS for user equipment not scheduled for data transmission. This multi-functional approach allows the base station to obtain channel state information from all user equipment through a unified triggering mechanism, resolving the limitation of the traditional scheduling-signaling-based approach.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements dynamics by enabling the base station to dynamically trigger SRS transmission from any user equipment through physical indication signals, regardless of whether the equipment is currently scheduled for data transmission. This dynamic triggering mechanism allows flexible adaptation to different channel state estimation needs, enabling the base station to request channel state information from specific user equipment at specific times based on actual network conditions.

Inventive Principle:

Principle #15Dynamics

2Productivity

If multiple systems share unlicensed spectrum resources, then spectrum utilization is improved, but carrier resources may be occupied by other systems, preventing LAA user equipment from sending SRS and causing incorrect channel state estimation

Engineering Contradiction:

Improvespectrum utilizationVSAvoidchannel state estimation accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by having the base station send physical indication signals to user equipment before the user equipment transmits SRS. This advance notification allows user equipment to prepare for SRS transmission and ensures the base station is ready to receive and correctly estimate the channel state. The preliminary signaling also enables the base station to coordinate SRS transmission timing with other system activities in the unlicensed spectrum, reducing conflicts and ensuring reliable channel state estimation.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If non-cycle SRS mechanism is used with dynamic activation by base station, then SRS can be triggered on-demand, but once activated, terminal device sends SRS only once and does not periodically send, limiting continuous channel state monitoring

Engineering Contradiction:

ImproveSRS triggering controlVSAvoidchannel state monitoring continuity

Core Design Contradiction:

Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent applies periodic action by enabling the base station to send multiple physical indication signals to user equipment at different time instances, triggering periodic SRS transmissions. Instead of a single one-time SRS transmission after activation, the base station can continuously monitor channel states by sending triggering signals at regular intervals or based on network conditions. This periodic triggering mechanism maintains continuous channel state monitoring capability while preserving the on-demand control flexibility of the non-cycle SRS mechanism.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10820208B2Sounding reference signal scheduling method, sounding reference signal sending method, and apparatuses thereof

Publication Date: 2020.10.27 BEIJING ZHIGU TECH SERVICE

AI summary

Embodiments of this application disclose a sounding reference signal scheduling method, a sounding reference signal sending method, and apparatuses thereof. The sounding reference signal scheduling method comprises: determining an available carrier in an unlicensed spectrum; and in response to the existing available carrier, sending, at least on the available carrier, a physical indication signal, wherein the physical indication signal comprises information related to scheduling of a sounding reference signal of at least one user equipment, and the physical indication signal is used at least to trigger the at least one user equipment to send a sounding reference signal. According to the methods and apparatuses in the embodiments of this application, scheduling information is placed in a physical indication signal that occupies an available carrier; therefore, a sounding reference signal can be scheduled more flexibly.