Multicast Protocol Reducing Latency and Energy in TDMA Networks

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current multicast communication protocols in low-power wireless networks, such as IEEE 802.15.4, face challenges in efficiently managing multicast packets, leading to high energy consumption, end-to-end latency, and reliability issues due to the lack of native multicast support and the use of unicast or broadcast transmissions.

Innovation Solution

A modified Bidirectional Multicast RPL Forwarding (BMRF) algorithm that allows for the selection between link layer unicast and broadcast communication, utilizing Time Slotted Channel hopping (TSCH) at the MAC layer to provide deterministic access and reduce interference, along with Time Division Multiple Access (TDMA) for reliable broadcast re-transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If link layer unicast transmission is used for multicast communication, then reliability is improved through acknowledgements, but energy consumption and end-to-end latency increase due to individual packet delivery to each subscriber

Engineering Contradiction:

ImprovereliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by transmitting broadcast packets only the necessary number of times (excessive but controlled) to achieve reliable delivery without full unicast redundancy. The system determines optimal retransmission counts based on network conditions, applying just enough repetition to ensure reliability while avoiding the excessive energy cost of full unicast to each node.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the transmission parameter from individual unicast packets to broadcast packets with controlled retransmission counts. This parameter change allows the system to maintain reliability through multiple transmissions while reducing energy consumption by using efficient broadcast mechanics rather than repeated unicast handshakes with each subscriber.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If link layer broadcast transmission is used for multicast communication, then energy consumption and end-to-end latency are reduced, but reliability deteriorates due to lack of acknowledgements

Engineering Contradiction:

Improveenergy consumptionVSAvoidreliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements periodic action through controlled retransmission of broadcast packets. Instead of single transmission, the system periodically retransmits broadcast packets a determined number of times, creating rhythmic transmission cycles that increase delivery probability while maintaining the energy efficiency of broadcast rather than continuous unicast acknowledgements.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent introduces feedback mechanisms where the system monitors transmission outcomes and adjusts retransmission counts accordingly. This feedback allows the broadcast system to improve reliability by retransmitting only when necessary, rather than always using energy-intensive unicast with acknowledgements, thus resolving the reliability-deficiency of basic broadcast.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If CSMA-based MAC layer is used for radio access, then ease of operation is improved, but end-to-end latency increases due to non-deterministic channel access and collision avoidance delays

Engineering Contradiction:

Improveease of operationVSAvoidend-to-end latency

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-scheduling transmission time slots and determining retransmission counts before actual data transmission. This preliminary planning eliminates the need for real-time collision avoidance delays, as nodes know in advance when they can transmit and how many retransmissions will occur, thus reducing end-to-end latency while maintaining operational simplicity.

Inventive Principle:

Principle #10Preliminary action

4Quantity of substance

If broadcast transmission is used with multiple subscribers, then bandwidth efficiency is improved, but energy is wasted when fewer subscribers are interested due to lack of selective delivery

Engineering Contradiction:

Improvebandwidth efficiencyVSAvoidenergy consumption

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by transmitting broadcast packets only the necessary number of times based on actual subscriber interest and network conditions. Rather than always using full unicast to each subscriber or unnecessary broadcast repetitions, the system determines the optimal partial number of transmissions needed to reach interested parties, thus avoiding energy waste while maintaining bandwidth efficiency.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP4005294B1Systems and methods for smart broadcast for multicast communication over an IP-based TDMA network

Publication Date: 2025.06.04 SAFRAN PASSENGER INNOVATIONS LLC

Figure 1
Figure 2
Figure 3

AI summary

Systems, processes and methods are described for increasing the reliability of packet delivery while reducing end-to-end latency and power consumption in a low power wireless network. The packet is forwarded during a transmit timeslot utilizing link layer broadcast transmissions. A preset number of retransmission timeslots are provided to retransmit the packet. To reduce energy consumption for recipients, a recipient can enter a sleep mode after receiving the packet for the remaining retransmit timeslots.