Adaptive RSSI Threshold for Wi-Fi to Cellular Offloading

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Solution Overview

Problem

Current wireless user terminals automatically switch to Wi-Fi connections over cellular networks without considering network conditions, leading to suboptimal service quality due to congestion or poor signal quality in Wi-Fi cells, even when cellular networks offer better performance.

Innovation Solution

Implementing a traffic steering method that correlates cellular network cells with Wi-Fi cells and uses an adaptive Received Signal Strength Indicator (RSSI) threshold to control access, ensuring users connect to Wi-Fi only when throughput is comparable to cellular networks, thereby optimizing network selection based on predicted performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If user terminals automatically switch to Wi-Fi connections, then data traffic is offloaded from cellular network, but service quality deteriorates when Wi-Fi is congested or has poor signal

Engineering Contradiction:
Improvedata traffic offloadingVSAvoidservice quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic network selection by continuously monitoring network conditions (signal strength, throughput, latency) and adapting the preferred network between Wi-Fi and cellular based on real-time performance. This resolves the contradiction by making the network selection flexible rather than static, ensuring service quality is maintained while still achieving traffic offloading when Wi-Fi conditions are favorable.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms that monitor network performance metrics and use this information to adjust network selection decisions. By continuously measuring actual service quality on Wi-Fi networks and comparing it against cellular network performance, the system can dynamically switch networks to maintain optimal service quality while achieving traffic offloading benefits.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If user terminals prefer Wi-Fi connections, then network selection is simplified, but performance deteriorates when Wi-Fi conditions are poor

Engineering Contradiction:
Improvenetwork selectionVSAvoiddata throughput
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent implements self-service network selection where the terminal autonomously evaluates network conditions and makes switching decisions without user intervention. The system automatically monitors signal strength, throughput, and other performance metrics, then independently determines whether to switch between Wi-Fi and cellular networks, maintaining both ease of operation and optimal data throughput.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The network selection process is made dynamic by continuously adapting to changing network conditions. The terminal automatically adjusts its preferred network based on real-time performance measurements, ensuring that data throughput is optimized while maintaining simple automated operation without requiring user configuration or intervention.

Inventive Principle:
Principle #15Dynamics

3Productivity

If strict Wi-Fi preference is enforced, then traffic offloading is maximized, but service reliability decreases during Wi-Fi congestion

Engineering Contradiction:
Improvetraffic offloadingVSAvoidconnection stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the parameter of network preference from a fixed strict preference to a dynamic preference based on network conditions. By monitoring parameters such as signal strength, throughput, and latency, the system adjusts its Wi-Fi preference level accordingly - maintaining strong Wi-Fi preference when conditions are good for maximum traffic offloading, but reducing preference or switching to cellular when congestion or poor signal threatens connection stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements dynamic network preference that adapts to changing Wi-Fi conditions. Rather than enforcing strict Wi-Fi preference unconditionally, the terminal continuously evaluates network performance and dynamically adjusts its preference, maintaining traffic offloading benefits when Wi-Fi is reliable while ensuring connection stability by switching to cellular when Wi-Fi degrades.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2989832B1Conditional offloading from WLAN to cellular network
Publication Date: 2019.08.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2989832B1 patent drawingFigure 1
  • EP2989832B1 patent drawingFigure 2A~2B
  • EP2989832B1 patent drawingFigure 3

AI summary

Wi Fi/3GPP access selection techniques are used to control selection by a user terminal between cellular network cells and Wi-Fi cells. Cellular network cells providing overlapping coverage with Wi-Fi cells are correlated with the Wi-Fi cells. A received signal strength threshold is determined for each Wi-Fi cell based on an average throughput of the cellular network cells correlated with the Wi-Fi cell. The Wi Fi user terminal admit threshold is used to control the effective coverage of the Wi-Fi cell. A user terminal operating within a cellular network cell is admitted to a Wi-Fi only if it is within the effective coverage area of the Wi-Fi cell as determined by the received signal strength threshold. Increasing the threshold shrinks the effective coverage area of the Wi-Fi cell to allow user terminal only of strong RSSI to make connection to the Wi Fi Cell, and steers user terminal of weak RSSI away from the Wi-Fi cell. In contrary, decreasing the threshold expands the effective coverage area of the Wi-Fi cell and effectively allows more user terminal making connection to the Wi-Fi cell.