Thread CSMA Sliding Window Channel Assessment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In wireless IoT networks, the increasing number of devices leads to conflicts over unlicensed channels, resulting in inefficient communication due to the lack of effective channel assessment and back-off mechanisms, which can cause collisions and transmission failures.

Innovation Solution

Implementing carrier-sense multiple access (CSMA) and carrier aggregation with sliding window-based channel assessment and back-off periods in thread devices, allowing them to determine channel occupancy and idle times accurately before transmitting, thereby reducing collisions and improving transmission success rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple devices transmit on unlicensed channels simultaneously, then communication throughput increases, but channel collisions increase and transmission reliability deteriorates

Engineering Contradiction:

Improvecommunication throughputVSAvoidtransmission reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing channel assessment before transmission through sliding window-based channel scans. Devices scan channels during initial and second sliding windows to detect occupancy status before attempting transmission, preventing collisions by ensuring the channel is idle first.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics through adaptive back-off mechanisms where the back-off duration is dynamically adjusted based on channel conditions. The second sliding window's third time period is determined based on power distribution from the initial sliding window, allowing the system to adapt transmission timing to current channel state.

Inventive Principle:

Principle #15Dynamics

2Reliability

If channel assessment is performed continuously, then transmission reliability improves, but energy consumption increases

Engineering Contradiction:

Improvechannel assessment accuracyVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by performing channel scans at specific intervals using sliding windows rather than continuously. The initial sliding window with N symbol durations is followed by a second sliding window with a third time period determined based on power distribution, creating a periodic assessment rhythm that balances reliability and energy consumption.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent implements partial action by performing channel assessment only for the necessary duration to determine channel occupancy. The third time period of the second sliding window is determined based on power distribution from the initial window, performing just enough scanning to make an informed transmission decision without excessive energy expenditure.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If back-off period is extended to reduce collisions, then transmission reliability improves, but transmission delay increases

Engineering Contradiction:

Improvecollision avoidanceVSAvoidtransmission delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamics through adaptive back-off mechanisms where the back-off duration is dynamically adjusted based on channel conditions. The third time period of the second sliding window is determined based on power distribution from the initial sliding window, allowing shorter back-off when channel is clear and longer back-off when occupied, optimizing both reliability and delay.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies feedback by using power distribution information from the initial sliding window to determine the duration of the third time period in the second sliding window. This feedback mechanism allows the system to adjust back-off duration based on actual channel occupancy patterns, reducing unnecessary delays while maintaining collision avoidance.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11510245B2Thread boost mode for carrier-sense multiple access/carrier aggregation (CSMA/CA)

Publication Date: 2022.11.22 APPLE INC

AI summary

An approach is described for a wireless device comprising a transceiver and a processor communicatively coupled to the transceiver. The processor is configured to detect a packet for transmission; scan, using the transceiver, a channel during an initial sliding window, the initial sliding window having N symbol durations; determine a power distribution of the initial sliding window based on the channel scan; determine that the channel is occupied during a first time period of the initial sliding window based at least on the power distribution; and determine a second sliding window having a second time period and a third time period. The second time period overlaps with the initial sliding window and a length of the third time period is determined based at least on the power distribution. The processor is further configured to scan, using the transceiver, the channel during the third time period; determine that the channel is idle during the third time period of the second sliding window; and transmit, using the transceiver, the packet to a second wireless device on the channel responsive to the third time period being idle.