Power-Constrained UE Wi-Fi Cellular Handoff
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Solution Overview
Problem
Link budget limited user equipment devices, such as wearable devices, face challenges in managing power consumption and maintaining effective communication due to limited wireless communication capabilities and smaller batteries, which hinders efficient handover between WLAN and cellular networks.
Innovation Solution
The user equipment device determines performance thresholds for non-cellular network connections and transitions its cellular radio from a non-communication state to an online state to perform handover of voice communications from the non-cellular network to the cellular network, allowing for efficient power management and data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cellular radio is kept in online state for seamless handover, then handover reliability is improved, but power consumption increases
Solution Approach 1:
The system performs preliminary actions by keeping the cellular radio in idle state (not fully offline) to maintain basic network registration and signaling capability. This allows the device to quickly transition to active state when handover is needed, without maintaining full power consumption continuously. The cellular side initiates handover preparation in advance, reducing the need for continuous monitoring on the wearable device.
Solution Approach 2:
The radio state is made dynamic rather than static. The cellular radio transitions between idle and active states based on network conditions and handover requirements. The system dynamically adjusts the operational state of the cellular radio, maintaining connectivity when needed while conserving power during stable Wi-Fi operation.
2Reliability
If the cellular radio transitions from non-communication state to online state for handover, then connection quality is improved, but handover time increases
Solution Approach 1:
The network side performs preliminary handover preparation actions before the actual handover is triggered. The cellular network pre-establishes the necessary signaling paths and network resources, so when the wearable device needs to handover, the cellular radio can transition to online state and immediately establish connection without full re-registration delays.
Solution Approach 2:
The cellular network acts as an intermediary that manages the handover process. The network controller coordinates the transition, managing the cellular radio state changes and network resource allocation, which streamlines the handover process and reduces the time required for the device to establish cellular connection.
3Use of energy by moving object
If Wi-Fi is used for data communication, then power consumption is reduced, but connection reliability deteriorates
Solution Approach 1:
The cellular network serves as a mediator or backup channel. While Wi-Fi is the primary communication interface for power efficiency, the cellular radio remains available as a mediator that can take over when Wi-Fi connection quality deteriorates. The system intelligently switches between these two communication paths based on connection conditions.
Solution Approach 2:
The system changes operational parameters by switching between Wi-Fi and cellular networks based on connection quality thresholds. When Wi-Fi connection parameters (signal strength, stability) fall below acceptable levels, the system transitions to cellular network, adjusting the communication parameters dynamically to maintain reliability while managing power consumption.
Data Source
AI summary
Methods and systems are disclosed for performing seamless voice call handover and data handoff between a cellular network and a non-cellular (e.g., Wi-Fi) network, by a link budget limited user equipment device (UE) in standalone mode. The cellular radio may be maintained in a non-communication mode when not in use, to prevent power and peak power issues that may be unique to link budget limited devices. In response to poor non-cellular performance in support of a voice call, the UE may transition the cellular radio from the non-communication state to an online state. If the cellular network indicates that packet-switched calls are supported, then the UE may initiate handover of the voice call to the cellular network. Various methods for seamless handoff of data communications are also disclosed, in both the presence and the absence of a voice call. Various metrics are disclosed to enhance handoff determinations.