Sensor Network Collision Reduction via Segmented CAP Phases
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Solution Overview
Problem
In sensor networks, collisions of telegrams occur when multiple sensor nodes try to communicate with a receiving node simultaneously, leading to energy wastage and unreliable data transmission due to the inability to discriminate between overlapping transmissions.
Innovation Solution
Divide the reception period into time segments with probabilities for each sensor node to send telegrams based on predetermined parameters, such as ordinal numbers, data age, or priority, to minimize collisions and ensure collision-free transmission periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple sensor nodes transmit telegrams simultaneously to a receiving node, then data transmission speed increases, but collision probability increases and transmission reliability deteriorates
Solution Approach 1:
The CAP phase is divided into multiple time segments (first CAP segment, second CAP segment, etc.), allowing sensor nodes to transmit telegrams in different time slots. This segmentation reduces collision probability while maintaining overall transmission throughput, as nodes can attempt retransmission in subsequent segments without blocking other transmissions entirely.
Solution Approach 2:
The system uses periodic synchronization telegrams and structured CAP phases with repeated transmission opportunities. Sensor nodes can attempt transmissions in periodic intervals, and the receiving node periodically opens reception windows, creating a rhythmic transmission pattern that manages collisions systematically while maintaining productivity.
2Loss of time
If sensor nodes transmit telegrams without synchronization, then transmission delay decreases, but collision probability increases and energy wastage increases
Solution Approach 1:
The receiving node sends synchronization telegrams before the CAP phase to pre-coordinate transmission times with sensor nodes. This preliminary synchronization establishes expected transmission windows, allowing nodes to prepare and transmit at optimal times without excessive delays, while the structured CAP phases prevent energy wastage from random collision-based retransmissions.
3Reliability
If a receiving node opens reception window for a long duration, then probability of receiving telegrams increases, but time resources are consumed and collision discrimination becomes more difficult
Solution Approach 1:
The reception window is divided into multiple CAP phases with distinct time segments. Each segment provides a controlled opportunity for telegram reception, maintaining high reception probability through multiple attempts while limiting the duration of each individual reception window. This segmentation allows the system to spread reception time across multiple shorter intervals rather than one long continuous window.
Data Source
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AI summary
The method involves prompting sensor nodes (B-D) to transmit sensor data e.g. status data, to a receiving node (A) by transmitting synchronization telegram (ST) upon collision-free reception of an application telegram. The sensor data is transmitted directly in a telegram (T) by the sensor nodes at which the sensor data to be transmitted is accumulated. A preset part of the sensor nodes is prompted to transmit telegrams for which the prompted nodes are encrypted in the synchronization telegram upon transmission of the synchronization telegram.