DCI-Based Semi-Persistent CSI-RS Allocation Latency and Reliability

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Solution Overview

Problem

Current methods for dynamic allocation and deallocation of semi-persistent CSI-RS measurements in wireless communication systems suffer from long allocation and deallocation latencies, particularly with MAC CE based approaches, and lack reliability in DCI based methods due to uncertainty about successful UE reception of dynamic allocation or deallocation signals.

Innovation Solution

Implementing DCI based dynamic allocation and deallocation for semi-persistent CSI-RS measurements, where the wireless device sends a first CSI report after receiving dynamic allocation signaling, and uses a separate trigger message for semi-persistent CSI reporting, allowing the network node to verify successful reception and ensuring reliable initiation and termination of measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If MAC CE based dynamic allocation and deallocation is used for semi-persistent CSI-RS measurements, then reliability of measurement initiation and termination is improved, but allocation and deallocation latencies increase

Engineering Contradiction:

Improvereliability of measurement initiation and terminationVSAvoidallocation and deallocation latencies

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the control signaling into two distinct parts: MAC CE based dynamic allocation signaling for initiating measurements, and a separate trigger message for activating semi-persistent CSI reporting. This segmentation allows the measurement initiation to be decoupled from the reporting activation, enabling faster response times while maintaining reliability through the two-stage approach.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by having the wireless device perform measurements on the semi-persistent CSI-RS resource immediately upon receiving the dynamic allocation signaling, before the semi-persistent CSI reporting is formally triggered. This preliminary measurement phase allows the device to be ready and configured, reducing the overall latency when the actual reporting needs to start.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If DCI based dynamic allocation is used for semi-persistent CSI-RS measurements, then allocation latency is reduced, but reliability deteriorates due to uncertainty about successful UE reception

Engineering Contradiction:

Improveallocation latencyVSAvoidreliability of signal reception verification

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where the network node monitors for the first CSI report from the wireless device after sending dynamic allocation signaling. If the network does not receive the expected CSI report within a predetermined time, it can determine that the dynamic allocation signaling was not successfully received and can retransmit or take corrective action, thereby verifying reception reliability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent uses the first CSI report as an intermediary verification mechanism. Instead of directly confirming receipt of the dynamic allocation signaling, the system uses the subsequent CSI report transmission as an indirect confirmation that the device successfully received and processed the allocation signaling, providing reliable verification without adding significant latency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If separate trigger message is used for semi-persistent CSI reporting activation, then measurement and reporting can be independently controlled, but signaling overhead increases

Engineering Contradiction:

Improveindependent control of measurement and reportingVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent makes the trigger message multi-functional by designing it to serve dual purposes: activating semi-persistent CSI reporting and simultaneously triggering aperiodic CSI reports. This universal trigger approach allows the network to control both reporting types with a single signaling event, reducing overall signaling overhead while maintaining the ability to independently control measurement and reporting activation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11184787B2Systems and methods for reliable dynamic indication for semi-persistent CSI-RS

Publication Date: 2021.11.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

According to certain embodiments, a method in a wireless device is provided that includes receiving, from a network node, dynamic allocation signaling to commence measurement on a semi-persistent CSI-RS resource. A first measurement is performed on the CSI-RS resource. A first CSI report based only on the first measurement is transmitted to the network node. A trigger message is received from the network node that is different from the dynamic allocation signaling. The trigger message triggers semi-persistent CSI reporting, and the wireless device initiates semi-persistent reporting.