Inter-Frequency Measurement Pattern for LTE Handover Latency
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Solution Overview
Problem
In LTE networks, the time required for user equipment (UE) to perform inter-frequency measurements across multiple FDD carriers increases linearly, leading to potential handover delays and increased power consumption when trying to reduce measurement time, which can result in interrupted or lost traffic for UEs in motion.
Innovation Solution
A mobility control unit estimates the UE's speed and determines a customized measurement pattern, transmitted by the eNB to the UE, indicating when to perform inter-frequency measurements, optimizing the measurement schedule to balance time constraints and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE performs inter-frequency measurements across multiple FDD carriers using traditional methods, then measurement completeness is improved, but the measurement time increases linearly causing handover delays
Solution Approach 1:
The patent segments the inter-frequency measurement process by introducing measurement patterns that divide measurements into different types (intra-pattern and inter-pattern) and organize them across multiple carriers in a structured sequence. This segmentation allows the UE to perform measurements on multiple carriers without requiring continuous measurement gaps, thereby reducing total measurement time while maintaining completeness.
Solution Approach 2:
The patent applies preliminary action by configuring measurement patterns in advance through RRC signaling before the actual measurements are performed. The measurement patterns, including intra-pattern and inter-pattern definitions, are pre-established so that the UE can efficiently execute measurements without real-time decision-making delays, thus reducing handover latency.
2Loss of time
If the measurement time is reduced to avoid handover delays, then responsiveness is improved, but power consumption increases due to accelerated measurement requirements
Solution Approach 1:
The patent implements periodic action through measurement patterns that define regular measurement occasions (intra-pattern) and less frequent inter-pattern measurements. This periodic structure allows the UE to enter low-power states between measurement occasions while still meeting measurement requirements, thereby reducing overall power consumption compared to continuous or accelerated measurement approaches.
Solution Approach 2:
The patent changes measurement parameters dynamically by allowing different measurement patterns to be configured for different carriers and different measurement types. The network can adjust measurement timing, frequency, and duration parameters to optimize the balance between measurement speed and power consumption based on specific network conditions and UE capabilities.
3Measurement precision
If traditional measurement scheduling is used, then measurement accuracy is maintained, but connection stability deteriorates due to measurement gaps causing traffic interruption
Solution Approach 1:
The patent introduces dynamics by implementing flexible measurement patterns that can be adapted to different network conditions and traffic types. The measurement timing and resource allocation are dynamically adjusted through RRC reconfiguration, allowing the system to maintain measurement accuracy while minimizing disruption to ongoing data transmissions, thus improving connection stability.
Data Source
AI summary
Systems and methods for improved inter-frequency measurement are disclosed herein. User equipment (UE) may be configured to communicatively couple to an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (eNB). The eNB may determine a measurement pattern indicating when the UE should perform inter-frequency measurements. The measurement pattern may be selected such that the UE performs measurements more often than once per measurement cycle. The measurement pattern may be selected to balance timing requirements for the UE with increased power consumption that may result from more frequent measurements. The eNB may determine the measurement pattern based on an estimate of UE speed and a number of frequencies to be monitored. A default pattern may be used if the UE speed and/or number of frequencies do not exceed predetermined thresholds.