Cellular Phone Power-Down Sequence Flag Mechanism
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Solution Overview
Problem
Existing wireless communication systems face ambiguity when a cellular radio powers down without receiving an acknowledgment signal from the network, leading to uncertainty about its operating state and potential misrouting of messages.
Innovation Solution
A cellular telephone sets a status flag in non-volatile memory if it does not receive an acknowledgment for its power-down message, allowing it to determine its network registration status upon powering up and requesting network access if necessary to update the network's database.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the cellular telephone sends a power-down message without waiting for acknowledgment, then the power-down sequence is completed quickly, but the network may not know whether the telephone is present or reachable
Solution Approach 1:
The patent applies preliminary action by having the cellular telephone send a power-down or de-registration message to the network controller before completing the power-down sequence. This advance notification allows the network to update its records and know that the telephone is transitioning to a powered-down state, resolving the information loss problem while maintaining quick power-down execution
Solution Approach 2:
The patent implements feedback by requiring the network controller to send an acknowledgment message back to the cellular telephone confirming receipt of the power-down message. This feedback loop ensures both the network and the telephone have consistent knowledge of the telephone's state, preventing ambiguity about whether the telephone is present or reachable
2Loss of information
If the cellular telephone waits for acknowledgment before completing power-down, then network knowledge of telephone state is maintained, but the power-down sequence takes longer
Solution Approach 1:
The patent applies preliminary action by sending the power-down message in advance during the power-down sequence, allowing the network to begin updating its records before the telephone fully powers down. This reduces the time the network is in an uncertain state while maintaining reliable state tracking
3Speed
If the cellular telephone does not receive an acknowledgment, then the power-down can be completed quickly, but the telephone powers up in an indeterminate state vis-a-vis the network
Solution Approach 1:
The patent applies preliminary action by having the telephone send the power-down message before completing the power-down sequence. This allows the network to be notified in advance, and if the telephone powers up in an indeterminate state, it can re-send the power-down message to re-establish consistent state knowledge
Solution Approach 2:
The patent implements beforehand cushioning by allowing the telephone to handle the scenario where acknowledgment is not received. The telephone is designed to re-send the power-down message upon power-up if needed, cushioning against the reliability issue of indeterminate states without slowing down the initial power-down execution
Data Source
AI summary
When a cellular telephone is powered down, it sends a power-down message to a network it was previously registered with. If the network does not send, or if the cellular telephone does not receive, an acknowledgement of the power-down message from the network, a status bit referred to as a flag is set (or reset) in a non-volatile memory device in the cellular telephone. The power-down sequence is concluded by the cellular telephone and, the cellular telephone is shut off or put into a reduced power consumption state. When the telephone is turned back on, i.e., returned to its previous state, the flag is evaluated or “tested” to see if it was set (or reset) during the course of powering down. The status or value of the flag when the phone is powered up is then used by the cellular telephone to determine whether it should make a network access request to a network the telephone was registered to, during the power-up operation in order to cause that cellular network to update its database regarding the whereabouts of the powered-up cellular telephone.