NR Downlink Measurement With Multi-Level Beam Filtering
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Solution Overview
Problem
The existing LTE measurement framework is inadequate for the beam-centric architecture of New Radio (NR) due to unsynchronized cells, beam blockage, and the need for flexible measurement configurations in diverse scenarios, leading to inefficiencies in cell quality derivation and mobility management.
Innovation Solution
A multi-beam multi-level mobility measurement model is introduced, utilizing idle mode RSs (e.g., NR-SS) and additional RSs (e.g., CSI-RS) with separate filtering and processing for different UE states and mobility levels, including Layer 1, 2, and 3 filtering to derive cell quality from beam measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the existing LTE measurement framework is used in NR beam-centric architecture, then device complexity is reduced by reusing established protocols, but measurement precision deteriorates due to inadequacy in handling beam blockage and unsynchronized cells
Solution Approach 1:
The measurement framework is segmented into multiple levels (Layer 1, Layer 2, Layer 3 filtering) and multiple RS types (idle mode RS and additional RS) to handle different UE states and mobility scenarios separately, allowing precise cell quality derivation for each scenario while maintaining overall framework manageability
Solution Approach 2:
The measurement framework is made dynamic by introducing state-dependent filtering parameters that adapt to different UE states (idle, connected, inactive) and mobility levels, enabling the system to adjust measurement precision according to actual network conditions rather than using fixed LTE parameters
2Measurement precision
If separate filtering and processing for different UE states is implemented, then measurement precision is improved for accurate cell quality derivation, but device complexity increases due to multiple filtering levels
Solution Approach 1:
Different filtering characteristics are applied locally to different UE states and mobility scenarios. Each state (idle, connected, inactive) has optimized filtering parameters tailored to its specific requirements, achieving high measurement precision for each scenario without requiring all devices to implement all filtering levels simultaneously
Solution Approach 2:
The framework performs preliminary measurements using idle mode RS before transitioning to additional RS measurements in connected state. This staged approach allows the system to prepare measurement data in advance and process it through appropriate filtering levels, reducing the computational burden during critical handover decisions
3Productivity
If measurement gaps are reduced to improve productivity, then handover speed is improved, but measurement precision deteriorates due to insufficient sampling time
Solution Approach 1:
The framework enables continuous measurement action by utilizing both idle mode RS (always available) and additional RS (scheduled during connection). This continuity allows the system to maintain measurement precision without relying solely on periodic measurement gaps, as measurements can be performed continuously using the always-available idle mode RS
Solution Approach 2:
The system performs preliminary beam measurements and identifies candidate beams using idle mode RS before actual handover execution. This preliminary action allows the network to prepare handover candidates in advance, reducing the need for extended measurement gaps during critical handover moments while maintaining measurement precision
Data Source
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AI summary
Measurement modeling and filtering may include configurable cell quality derivation method is used for multi-beam based NR networks; a common measurement model that considers different characteristics of the two measurement signals, NR synchronization signal and additional reference signal; and a multi-level measurement filtering approach that handles different mobility scenarios in an NR network. Measurement configuration and procedures may include a measurement gap design during which UE may use to perform measurements for beam sweeping based NR networks; a group of triggering events that may be used to trigger UE mobility management in an NR network; a content format that may be used for the transmission of UE measurement report; a measurement object design (the object on which a UE may perform the measurements) to reduce UE measurement overhead and cost; and a downlink measurement based inter-cell handover procedure that may be used in an NR network.