Wireless Network Node Collision Avoidance via Promiscuous Timing
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Solution Overview
Problem
Wireless networks face collisions due to the hidden node and exposed node problems, where nodes cannot sense each other's transmissions, leading to inefficiencies and increased congestion, especially in dense networks with small maximum transfer units like ZigBee and IoT applications.
Innovation Solution
A network node operates in promiscuous mode to receive acknowledgments, determine timing information from these acknowledgments, and use this information to schedule transmissions, reducing the probability of collisions without relying on RTS/CTS messages, thereby reducing network traffic and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RTS/CTS messages are used to avoid collisions, then collision avoidance is improved, but network congestion and overhead increase
Solution Approach 1:
The patent extracts only the essential timing information from the RTS/CTS handshake procedure, discarding the actual RTS/CTS message exchange. Nodes capture timing data from overheard acknowledgments and use this extracted information for collision avoidance, eliminating the overhead of full RTS/CTS messages while retaining the collision avoidance benefit
Solution Approach 2:
The patent performs preliminary timing information collection by having nodes operate in promiscuous mode to capture acknowledgments before actual data transmissions occur. This preliminary action allows nodes to pre-determine transmission schedules based on observed timing patterns, avoiding the need for real-time RTS/CTS negotiation
2Ease of operation
If nodes use CSMA/CA with carrier sensing, then simple protocol operation is maintained, but hidden node collisions cannot be avoided
Solution Approach 1:
The patent introduces timing information derived from overheard acknowledgments as an intermediary mechanism. This timing information acts as a mediator that provides hidden nodes with knowledge of ongoing transmissions without requiring direct carrier sensing or complex RTS/CTS handshakes, thus maintaining protocol simplicity while improving reliability
Solution Approach 2:
The patent segments the collision avoidance function from the main data transmission protocol. Instead of integrating complex sensing or handshake procedures into the data path, it separates timing information collection (done via promiscuous mode listening) from data transmission, allowing simple CSMA/CA operation while adding reliability through the segmented timing-based scheduling layer
3Reliability
If promiscuous mode listening is used to gather timing information, then collision avoidance is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic promiscuous mode listening intervals rather than continuous monitoring. Nodes alternately switch between active data transmission and periodic timing information collection, reducing energy consumption while still gathering sufficient timing data for effective collision avoidance scheduling
Solution Approach 2:
The patent enables nodes to self-configure their transmission schedules by autonomously extracting timing information from overheard acknowledgments. This self-service approach eliminates the need for centralized coordination or continuous energy-intensive monitoring, as each node independently learns and adapts to network timing patterns
Data Source
AI summary
A network node for a wireless network and corresponding methods for reducing collisions in a wireless network, a wireless network, a wireless sensor network and a smart building including a wireless sensor network. The network node includes a processor, memory and an antenna. The network node is operable in a promiscuous mode to: receive at least one acknowledgement, wherein each acknowledgement is an acknowledgement of a respective transmission sent by another node through the wireless network; determine, from the at least one acknowledgement, timing information relating to the timing of the respective transmission(s) sent by the other node; and use the timing information to schedule transmissions sent by the node to reduce the probability of collisions of with transmissions sent by the other node.