LTE Handover Based on SINR Quality Metrics
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Solution Overview
Problem
In 4G LTE networks, wireless communication devices often experience poor connection quality due to high signal strength but low signal quality, primarily caused by interference from overlapping cells, leading to unstable data rates and VoLTE audio issues, as current handover decisions rely on signal power rather than quality metrics.
Innovation Solution
A method where wireless communication devices measure and compare signal-to-interference-plus-noise ratio (SINR) across cells, modifying measurement reports to trigger handovers to neighbor cells with better channel quality, and adjust uplink transmissions based on estimated interference to achieve target block error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover decisions are based on signal power levels (RSRP), then the handover process is simple and fast, but connection quality and throughput are degraded due to interference from overlapping cells
Solution Approach 1:
The patent changes the handover decision parameter from signal power (RSRP) to signal quality (SINR). The mobile device measures SINR values for both serving and neighbor cells, and uses these quality metrics to trigger handovers. This parameter change directly addresses the technical contradiction by prioritizing connection quality over simple power-based decisions, thereby resolving the issue of poor throughput despite strong signal strength.
Solution Approach 2:
The patent replaces the traditional network-controlled handover mechanism with a device-side autonomous decision mechanism. Instead of relying on the network to make handover decisions based on reported RSRP values, the mobile device autonomously measures SINR, compares quality metrics, and modifies measurement reports to trigger handovers. This substitution enables quality-based decisions at the device level, improving connection quality while maintaining operational simplicity.
2Productivity
If the mobile device measures and compares SINR for handover decisions, then connection quality and throughput are improved, but the measurement and processing complexity increases
Solution Approach 1:
The patent implements partial measurement action by measuring SINR only on specific resource elements that carry reference symbols from serving and neighbor cells, rather than measuring across all resource elements. The device interpolates SINR values to a range of resource elements across multiple resource blocks spanning an averaging time interval. This partial measurement approach reduces processing complexity while still providing sufficient quality information for handover decisions, thereby enabling improved throughput without excessive complexity.
Solution Approach 2:
The mobile device performs autonomous SINR measurement, comparison, and handover triggering without requiring complex network-side processing. The device measures SINR on reference symbols, computes quality metrics locally, and autonomously modifies measurement reports to trigger handovers when quality conditions are met. This self-service approach enables quality-based handovers with minimal network involvement, improving throughput while keeping device complexity manageable.
3Reliability
If the mobile device modifies measurement report values to trigger handover, then handover to better quality cells is achieved, but measurement report accuracy is compromised
Solution Approach 1:
The patent introduces SINR-based quality metrics as an intermediary layer between raw signal measurements and handover decisions. Instead of directly modifying RSRP values in measurement reports, the device measures SINR, uses it to determine handover eligibility, and then modifies report values accordingly. This intermediary quality metric enables reliable handover decisions based on actual connection quality while maintaining a structured approach to measurement reporting, balancing handover reliability with measurement precision.
Data Source
AI summary
Method and apparatus to trigger a handover of a mobile device from a serving cell to a neighbor cell based on signal quality are disclosed. The mobile device measures signal strength and signal quality for the serving cell. When the signal strength exceeds a network-defined threshold and the signal quality falls below a mobile device defined threshold, the mobile device measures at least one neighbor cell. When a neighbor cell exceeds the network-defined threshold for signal strength and also meets the mobile device defined signal quality threshold, the mobile device sends a measurement report to the serving cell to trigger the handover. The measurement report includes modified values that indicate the serving cell does not meet network-defined threshold values and that the neighbor cell outperforms the serving cell.