Wireless Sensor Network Tone Patterns for Message Type Identification
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Solution Overview
Problem
In wireless sensor networks, nodes often experience interference and collisions during the radio-frequency (RF) wakeup procedure, making it challenging to correctly determine the message type when awakened by multiple nodes simultaneously, which can lead to incorrect actions being performed.
Innovation Solution
A specific tone or pattern of tones is sent after the wakeup tone to indicate the required action for the awakened node, using distinct frequencies or patterns to differentiate message types, allowing nodes to determine the message type even in the presence of multiple transmitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nodes wake up periodically to sample the wireless channel for wakeup signals, then energy consumption is reduced by keeping nodes in power down mode most of the time, but interference and collisions occur when multiple nodes are simultaneously awakened by multiple transmitters
Solution Approach 1:
The patent introduces a tone signal as an intermediary between the wakeup signal and the data packet. This tone signal carries message type information that helps the awakened node correctly identify the type of message being sent, even when multiple transmitters are active simultaneously. The tone acts as a mediator that resolves the ambiguity caused by simultaneous wakeups and enables reliable message type determination despite the energy-efficient sleep-wake operation mode.
2Reliability
If nodes remain in active mode to receive messages after being awakened, then message reception reliability is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic wake-up operation where nodes transition between sleep and active modes at regular intervals. During each wake period, nodes sample the channel for wakeup signals and tone indicators. This periodic action allows nodes to maintain message reception capability while minimizing energy consumption by staying in low-power mode for most of the time, only becoming active when a wakeup signal is detected.
3Adaptability or versatility
If multiple transmitters send wakeup signals simultaneously, then network coverage and message delivery opportunities increase, but interference and collisions make it difficult to determine message type correctly
Solution Approach 1:
The patent applies local quality by assigning different characteristics (tones) to different message types. Each transmitter embeds a specific tone pattern that corresponds to the type of message being sent. This allows the receiver to locally distinguish between different message types even when multiple transmitters are active simultaneously, preventing information loss about message type despite the increased network coverage and simultaneous transmissions.
Data Source
AI summary
A system and method for operating a wireless network provides for sending a wakeup tone, periodically waking up from a sleep mode to listen for the wakeup tone, upon receiving the wakeup tone, listening for at least one second tone, the at least one second tone being one of (i) a tone in a frequency different from the wakeup tone and (ii) a pattern of tones including at least one frequency different from the wakeup tone, and upon receiving the at least one second tone, performing an action based on the at least one second tone.