Connected Mode Mobility Measurement for Narrowband UEs
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Solution Overview
Problem
Narrowband UEs, such as Cat-M1 UEs, face challenges with connected mode mobility due to the need for measurement gaps, which interrupt communications and are computationally burdensome for network scheduling, especially as more devices are deployed, leading to increased scheduling demands and interference with non-narrowband UEs.
Innovation Solution
Narrowband UEs autonomously collect signal quality measurements from neighboring cells, reducing the need for network-scheduled measurement gaps by tuning opportunistically to measure and report cell reference signals, thereby aiding handover decisions and minimizing communication interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement gaps are scheduled for narrowband UEs to perform connected mode mobility measurements, then signal quality measurement capability is improved, but communication interruptions increase and network scheduling complexity increases
Solution Approach 1:
The narrowband UE autonomously determines measurement timing and performs measurements without network-scheduled measurement gaps. The UE self-manages the measurement process by selecting appropriate PRBs and timing based on its own reception schedule, eliminating the need for network coordination and reducing communication interruptions.
Solution Approach 2:
The network provides measurement configuration information in advance through system information blocks or RRC messages, including neighbor cell frequencies and measurement objects. This preliminary provision of measurement parameters allows the UE to perform autonomous measurements without requiring real-time network scheduling of measurement gaps.
2Measurement precision
If measurement gaps are scheduled for narrowband UEs, then mobility measurement capability is improved, but network computational burden increases
Solution Approach 1:
The UE autonomously determines measurement timing and performs measurements without network-scheduled measurement gaps. The UE self-manages the measurement process by selecting appropriate PRBs and timing based on its own reception schedule, eliminating the need for network coordination and reducing communication interruptions.
Solution Approach 2:
The measurement scheduling function is extracted from the network and transferred to the UE. Instead of the network scheduling measurement gaps for each UE, the UE independently determines when and how to perform measurements, significantly reducing network computational burden especially when serving thousands of narrowband UEs.
3Measurement precision
If narrowband UEs tune away from allocated PRBs to perform measurements, then neighbor cell signal quality can be measured, but communication with serving cell is interrupted
Solution Approach 1:
The UE performs measurements on only the necessary center six PRBs rather than tuning away from all allocated PRBs. By limiting measurements to specific PRBs that carry synchronization signals and reference signals, the UE can obtain neighbor cell measurements while maintaining communication on other allocated PRBs, reducing communication interruptions.
Solution Approach 2:
The network provides measurement configuration information in advance through system information blocks or RRC messages, including neighbor cell frequencies and measurement objects. This preliminary provision of measurement parameters allows the UE to perform autonomous measurements without requiring real-time network scheduling of measurement gaps.
Data Source
AI summary
A method, apparatus, and system for lessening impact of connected mode mobility measurement is disclosed. A user equipment (UE) may reduce network management complexity by autonomously collecting signal quality measurements for neighboring cells. By autonomously tuning at opportune times for the UE, signal quality measurements may be obtained and reported to a serving cell. In another implementation, the UE examines the broadcast system information of both the serving base station against that of the neighboring base stations. Based on the included bandwidth information, the UE selects appropriate narrowband radio frequency subcarriers to perform signal quality measurement.