Time Slot Subslot Segmentation for Wireless Sensor Network Collision Avoidance

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Solution Overview

Problem

In wireless sensor networks, data packet collisions during time-multiplexed channel transmission lead to unreliable data reception due to simultaneous transmissions from different transmitters, causing energy inefficiency and network synchronization issues.

Innovation Solution

Implementing a transmitter with a time slot selector and data packet position selector to dynamically choose a time slot and position within it for each data packet, and a receiver with a time slot analyzer to detect collisions and generate information for adjusting transmission times, thereby reducing collisions and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data packets are transmitted simultaneously over a time-multiplexed channel, then data transmission rate is improved, but collision probability increases causing reliability to deteriorate

Engineering Contradiction:
Improvedata transmission rateVSAvoiddata reception reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The time slot is segmented into multiple subslots, and the data packet position within the time slot is varied by selecting different subslots. This segmentation allows multiple transmitters to share the same time slot without permanent collisions, as they can transmit at different subslot positions, thereby maintaining high transmission rates while improving reception reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The data packet position within the time slot is dynamically varied for at least every i-th data packet transmission. This dynamic adjustment prevents permanent collisions by ensuring that if one transmitter uses a particular subslot, another transmitter can use a different subslot in subsequent transmissions, resolving the contradiction between transmission rate and reliability.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If transmitters use fixed time slots for data transmission, then network synchronization is simplified, but collision probability increases when multiple transmitters share the same time slot

Engineering Contradiction:
Improvenetwork synchronizationVSAvoidcollision avoidance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The time slot is divided into multiple subslots, allowing transmitters to maintain synchronization on the same time slot while avoiding collisions by transmitting at different subslot positions. This segmentation approach preserves the simplicity of time slot-based synchronization while adding a layer of collision avoidance through subslot differentiation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different subslots within the same time slot provide different local transmission qualities or positions. Transmitters can be assigned different subslot positions locally within the time slot structure, allowing them to coexist without collisions while maintaining overall network synchronization at the time slot level.

Inventive Principle:
Principle #3Local quality

3Reliability

If data packets are retransmitted after collisions, then data delivery reliability is improved, but energy consumption increases

Engineering Contradiction:
Improvedata delivery reliabilityVSAvoidtransmitter energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary actions by varying the data packet position before collisions occur. By proactively selecting different subslot positions for different transmitters, the system prevents collisions from happening in the first place, thereby avoiding the need for energy-consuming retransmissions while ensuring reliable data delivery.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention converts the potential harm of collisions into a benefit by using the collision detection mechanism to dynamically assign different subslot positions. What would traditionally be a waste of energy (collisions followed by retransmissions) is transformed into an efficient collision avoidance mechanism that reduces overall energy consumption while maintaining reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If transmitters vary their transmission position within a time slot, then collision probability is reduced, but device complexity increases

Engineering Contradiction:
Improvecollision avoidanceVSAvoidtransmission coordination complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The time slot is segmented into multiple subslots, providing a simple structural framework for position variation. This segmentation approach adds minimal complexity by simply dividing the existing time slot into discrete positions, making it easy for transmitters to select different positions without requiring complex coordination mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the positional parameter of data packet transmission within the time slot. By varying this single parameter (subslot position) rather than implementing complex protocol changes, the system achieves collision avoidance with minimal increase in device complexity, as transmitters only need to select from predefined position options.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2560453B1Method for network organization
Publication Date: 2019.09.11 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP2560453B1 patent drawingFigure 1
  • EP2560453B1 patent drawingFigure 2
  • EP2560453B1 patent drawingFigure 3~4

AI summary

A transmitter for sending data packets over a time-multiplexed channel comprises a time slot selector for selecting a time slot for transmitting a data packet; and a data packet position selector for selecting a data packet time position within the selected time slot, wherein the data packet time position is selected anew for at least every ith data packet. The transmitter is configured for transmitting the data packet in the selected time slot and the selected data packet position within the selected time slot. A method for transmitting data packet is also disclosed. Furthermore, a receiver, a method for receiving data packets and a computer program are additionally described.