Alternating Frequency Wireless Alarm Communication
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Solution Overview
Problem
Existing wireless communication systems for social alarms, such as those used by elderly or disabled individuals, often experience signal degradation due to standing waves in specific environments, leading to failed connections and inability to transmit alarm signals, which cannot be effectively addressed by increasing transmitter power without reducing battery life or violating regulations.
Innovation Solution
A method and device that utilize two alternating frequencies for communication, where the primary frequency is used under normal conditions and switched to a secondary frequency if communication is not established, with the first unit remaining in a primary receiving mode for a longer duration than the secondary mode to improve connection reliability without increasing complexity or power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power of the transmitter of the mobile unit is increased to improve signal level in standing wave environments, then the signal quality is improved, but the battery life is shortened
Solution Approach 1:
The patent changes the frequency parameter of the radio signal from a single fixed frequency to multiple alternating frequencies. By switching between different frequency bands (e.g., 869.2 MHz and 869.4 MHz), the system finds frequencies that are not affected by standing waves, thereby improving signal quality without increasing transmitter power and preserving battery life.
2Reliability
If frequency-hopping techniques are used to improve resistance to radio frequency interference, then the reliability is improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent segments the frequency band into multiple discrete channels and alternates between them in a predetermined sequence. This segmentation approach simplifies the control system compared to continuous frequency-hopping, as the transmitter and receiver only need to switch between a limited set of predefined frequencies rather than continuously synthesizing new frequencies.
Solution Approach 2:
The patent implements periodic switching between different frequency channels according to a predetermined sequence. This periodic action allows both transmitter and receiver to synchronize easily by following the same timing pattern, reducing the complexity of synchronization mechanisms while maintaining reliability.
3Device complexity
If a single predetermined frequency is used for communication, then the device complexity is minimized, but the reliability fails in standing wave environments
Solution Approach 1:
The patent makes the communication system multi-functional by enabling it to operate on multiple frequency channels. The transmitter and receiver are designed to handle several frequencies, making the system adaptable to different environmental conditions caused by standing waves, thereby improving reliability without significantly increasing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly enhances the probability of establishing a reliable radio communication session between the mobile unit and the base unit, ensuring effective alarm signal transmission even in environments with standing waves, while minimizing battery drain and maintaining compliance with regulatory standards.
Implementation Method 1
a first unit (10) and a mobile second unit (12) both comprise a transmitter and a receiver operating at the same frequency
Data Source
Figure 1~2
Figure 3
AI summary
A method and a device for wireless communication between a first unit (10) and at least one second unit (12). The second unit (12) is activated by a user to send an alarm signal at a first frequency. If the second unit (12) does not receive an acknowledge signal at said first frequency from the first unit (10) after repeating the alarm signal the second unit (12) repeats the sending of an alarm signal at a second frequency. The first unit continuously alternates between said first frequency and said second frequency, so as to be able to receive the alarm signal. After receiving the alarm signal an acknowledge signal is sent using the same frequency as the frequency of the alarm signal. The device includes a conventional radio chip (14), a switch (18) and a micro controller (22). The micro controller controls the radio chip and the switch to send and receive at alternating frequencies.