Wireless Network Node Reducing False Collisions
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Solution Overview
Problem
Wireless networks face issues with hidden and exposed node problems, leading to false collisions due to the inability of nodes to sense each other's transmissions, especially in dense networks with small maximum transfer units, which can result in unnecessary congestion and power consumption, particularly problematic in low-power applications like ZigBee and IoT networks.
Innovation Solution
A network node equipped with a processor, memory, and an antenna that promiscuously monitors transmissions and acknowledgments, maintains a record, and sends information to other nodes to determine if they are hidden, allowing them to transmit without causing collisions, thereby reducing false collisions and optimizing network efficiency without relying on RTS/CTS messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nodes use CSMA/CA protocol to sense transmissions before transmitting, then collision avoidance is improved, but hidden node problems cause false collisions and reduce network efficiency
Solution Approach 1:
The patent applies preliminary action by having nodes send buffer status information to neighboring nodes before actual data transmission occurs. This allows nodes to proactively inform others of their transmission intentions and buffer states, enabling receiving nodes to make informed decisions about whether to transmit, thereby preventing false collisions before they happen.
Solution Approach 2:
The patent implements feedback mechanisms where nodes continuously exchange buffer status information with neighboring nodes. This feedback loop allows nodes to update their understanding of network conditions in real-time, adjusting their transmission decisions based on current buffer states of neighbors, thus reducing false collisions while maintaining high network utilization.
2Reliability
If RTS/CTS messages are used to reduce hidden node problems, then collision reduction is improved, but network congestion increases and power consumption rises
Solution Approach 1:
The patent extracts the essential collision avoidance function from the complex RTS/CTS handshake protocol. Instead of requiring full RTS/CTS message exchanges, the patent extracts only the critical buffer status information exchange needed to prevent false collisions, thereby maintaining collision reduction benefits while eliminating the excessive overhead and power consumption of complete RTS/CTS procedures.
Solution Approach 2:
The patent applies partial action by implementing a simplified version of the RTS/CTS mechanism. Rather than exchanging complete RTS and CTS messages with all their overhead, the patent exchanges only the necessary buffer status information, achieving sufficient collision avoidance without the excessive action of full handshake protocols.
3Productivity
If nodes transmit data immediately when channel is sensed idle, then network throughput is improved, but false collisions occur due to exposed node problems
Solution Approach 1:
The patent applies preliminary action by having nodes exchange buffer status information before transmitting data. This preliminary exchange allows nodes to determine whether neighboring nodes have empty buffers, enabling immediate transmission when safe while preventing false collisions when neighbors are also transmitting, thus maintaining high throughput with improved reliability.
Data Source
AI summary
A network node for a wireless network and corresponding methods for reducing false 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 promiscuously to monitor and maintain a record of transmissions and acknowledgements received by the network node. The network node is also operable to send information relating to the record to another node in the network for use by the other node in determining that a further node to which the other node sends transmissions is hidden from the network node. In another aspect the network node is operable to determine from information received from a second other network node, that a first other network node is hidden from the second other network node.