Wireless MAC Protocol Beacon Synchronization for Collision Avoidance

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Solution Overview

Problem

In wireless networks, especially those with low power transmitters and mobile nodes, the hidden and exposed terminal problems lead to collisions and inefficiencies due to the inability of nodes to detect ongoing transmissions, resulting in reduced communication reliability and increased energy consumption.

Innovation Solution

Implementing a method where nodes synchronize using beacons and scheduled data transmission periods, with the option to spread transmissions over multiple frequency channels using spread spectrum techniques, to minimize collisions and reduce energy usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nodes transmit data continuously to maintain communication reliability, then communication reliability is improved, but energy consumption increases

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic beacon transmission and scheduled data transmission slots instead of continuous transmission. Nodes wake up at specific intervals to transmit beacons and receive data during scheduled slots, then return to sleep mode. This periodic operation maintains communication reliability by ensuring regular network synchronization and data exchange while dramatically reducing energy consumption compared to continuous transmission.

Inventive Principle:

Principle #19Periodic action

2Reliability

If nodes use carrier sensing to detect ongoing transmissions, then collision avoidance is improved, but the protocol becomes ineffective in hidden terminal scenarios

Engineering Contradiction:

Improvecollision avoidanceVSAvoideffectiveness in hidden terminal scenarios

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses periodic beacon transmission as a preliminary action to establish network synchronization and announce transmission schedules before actual data transmission occurs. Nodes transmit beacons at predetermined intervals and include information about upcoming data slots, allowing other nodes to plan their transmissions in advance and avoid collisions even when they cannot sense ongoing transmissions due to hidden terminal problems.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The beacon signal acts as an intermediary that carries scheduling information between nodes. Instead of relying on direct carrier sensing between transmitting and receiving nodes, the beacon serves as a medium through which nodes communicate their transmission intentions and schedules, enabling collision avoidance in hidden terminal scenarios where direct sensing is ineffective.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the network uses time-slotted frames with beacon periods to organize transmissions, then collision reduction is improved, but protocol complexity increases

Engineering Contradiction:

Improvecollision reductionVSAvoidprotocol complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the communication medium into distinct time slots within periodic frames, with specific slots allocated for beacon transmission and other slots for data transmission. This segmentation organizes random access into structured intervals, reducing collisions by ensuring that nodes transmit beacons and data in designated slots rather than continuously competing for the medium. The segmented structure simplifies collision management while maintaining reasonable protocol complexity through regular, predictable patterns.

Inventive Principle:

Principle #1Segmentation

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 reduces the number of collisions, minimizes energy consumption, and enhances communication reliability by ensuring nodes transmit and receive data efficiently, even in environments with hidden and exposed terminal issues, while maintaining network synchronization.

Implementation Method 1

nodes transmit and receive data efficiently over shared wireless channels

Methodology Applied

Scientific EffectElectromagnetic radiation:

Implementation Method 2

spread transmissions over multiple frequency channels using spread spectrum techniques

Methodology Applied

Scientific EffectSpread spectrum:

Data Source

PatentEP2453705B1Method and system for media access control protocol in a network

Publication Date: 2020.04.29 HP VENTURES AS

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Figure 1C~1D

AI summary

A method for a device to communicate in one operational mode over a wireless network uses any suitable media access control mechanism for periodically communicating scheduled data transmission information between nodes. Scheduled data is then periodically transmitted according to the scheduled data transmission information and neighbor scheduled data is periodically listened for according to the neighbor scheduled data transmission information. Finally, the device is otherwise allowed to enter in a different operational mode.