Randomized Preamble Binary Words for Battery-Powered IoT Peripherals
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Solution Overview
Problem
In building automation and alarm systems, peripherals with limited battery power experience reduced operating time due to unnecessary radio module activations caused by detecting preambles from nearby centralized devices, leading to frequent battery replacements or recharging.
Innovation Solution
A method and device that randomly select binary words for a preamble, optimizing radio frequency reception by using autocorrelation and intercorrelation criteria to minimize prolonged listening and synchronization errors, thereby reducing power consumption and avoiding interference from other devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined preamble is used by multiple centralized devices, then devices can detect and synchronize with radio frames, but peripheral devices experience unintended activations due to detecting preambles from unauthorized centralized devices
Solution Approach 1:
The preamble is segmented into two parts: a first part (p1) that is predetermined and known by all devices, and a second part (p2) that is randomly generated and specific to each centralized device. This segmentation allows peripheral devices to efficiently detect the presence of a radio frame using the common first part while uniquely identifying the authorized centralized device through the second part, thereby preventing unintended activations from unauthorized devices.
Solution Approach 2:
Different parts of the preamble serve different functions with different requirements. The first part (p1) is designed for universal detection and synchronization with specific properties (such as alternating bits pattern), while the second part (p2) is customized for each centralized device to provide unique identification. This local quality differentiation resolves the contradiction by optimizing each part for its specific purpose.
2Reliability
If the radio module remains active to detect preambles continuously, then no preamble is missed, but battery power is consumed excessively
Solution Approach 1:
The radio module operates in periodic cycles rather than continuously. It alternates between active detection phases (listening for preambles) and sleep phases (low power consumption). During active phases, the module detects preambles and processes data frames. During sleep phases, it consumes minimal power. This periodic operation maintains reliable detection capability while significantly reducing average power consumption compared to continuous operation.
Solution Approach 2:
The system uses the structure of the radio frame itself (the preamble) to trigger activation. Instead of using an external timer or control signal to wake the radio module, the module remains in a low-power state and is automatically activated only when it detects the specific preamble pattern in the radio frequency environment, making the activation self-triggered and energy-efficient.
3Object-affected harmful factors
If a unique preamble is assigned to each centralized device, then unintended activations are prevented, but the complexity of preamble management increases
Solution Approach 1:
The preamble structure is segmented into a common first part (p1) and a device-specific second part (p2). The first part can be hard-coded or pre-configured in all devices, eliminating the need for complex distribution and management. Only the simpler second part needs to be uniquely assigned to each centralized device, significantly reducing overall system complexity compared to managing entirely unique preambles.
Solution Approach 2:
The system merges a standardized, universally-known preamble structure (first part) with device-specific identification data (second part). This combination allows all devices to share common detection logic for the first part while maintaining unique identification through the second part, simplifying the overall management architecture compared to using completely custom preambles for each device.
Data Source
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AI summary
The invention relates to a method for determining binary words forming a preamble of a data frame transmitted by a centralised device to a peripheral device, wherein the centralised device: - detects (E300) when the centralised device is set to a connection mode; - randomly selects (E301) a sub-set of binary words; - randomly selects (E302), from the selected sub-set, a first and a second binary word; - transfers (E304) a data frame formed by a predetermined preamble and by at least one data packet comprising at least the first and second selected binary words; - receives (E305) a data frame transferred in response by a peripheral device and connects the peripheral device to the centralised device; - uses (E306) the first and second selected binary words to form a preamble formed by the concatenation of the two selected binary words in order to transfer each data frame to the connected peripheral device.