Intelligent Busy Tone Generator for Wireless Collision Avoidance
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Solution Overview
Problem
Existing wireless communication systems face challenges in avoiding communication transmission collisions, particularly in hidden-node scenarios, where nodes are not directly visible to each other, leading to interference and inefficiencies in bandwidth usage, as current solutions like RTS/CTS protocols are not fully effective and require hardware adaptations or consume bandwidth.
Innovation Solution
An intelligent busy tone generator (IBTG) is introduced in the access point to transmit a busy tone upon uplink preamble acquisition, significantly shortening the collision window by mimicking a carrier sequence, allowing hidden nodes to detect channel occupancy without altering existing wireless devices or consuming additional bandwidth, and incorporating interference cancellation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RTS/CTS protocols are used to address hidden-node problem, then collision avoidance is improved, but bandwidth consumption increases and device complexity increases
Solution Approach 1:
The patent extracts the essential function of collision notification from the complex RTS/CTS handshake protocol. Instead of requiring full RTS/CTS exchanges, the access point extracts and transmits only the necessary collision warning information through a simplified busy tone mechanism, reducing bandwidth consumption while maintaining collision avoidance effectiveness.
Solution Approach 2:
The patent creates a simplified copy of the collision notification function. Rather than implementing the complete RTS/CTS protocol stack, the system uses a busy tone that copies the essential warning signal function, eliminating the need for complex packet exchanges while preserving the core collision avoidance capability.
2Reliability
If RTS/CTS protocols are used to address hidden-node problem, then collision avoidance is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential collision warning function from the RTS/CTS protocol suite. The access point monitors uplink transmissions and generates simple busy tone signals, eliminating the need for complex RTS/CTS packet processing and protocol state management at both access point and client devices.
Solution Approach 2:
The system implements a simplified copy of the collision notification mechanism. Instead of full RTS/CTS protocol stacks, devices use basic busy tone detection and generation capabilities, dramatically reducing the complexity of protocol implementation while maintaining the essential collision avoidance function.
3Productivity
If carrier sense with collision avoidance is used, then bandwidth utilization is improved, but hidden-node interference increases
Solution Approach 1:
The patent implements a feedback mechanism where the access point monitors uplink transmissions from hidden nodes and generates busy tone signals in response. This feedback loop allows the access point to notify hidden nodes of ongoing transmissions, enabling them to sense the busy channel state and avoid collisions, thus maintaining high bandwidth utilization while eliminating hidden-node interference.
Solution Approach 2:
The access point acts as an intermediary between hidden nodes. It monitors the wireless medium, detects ongoing transmissions, and generates busy tone signals that mediate communication between hidden nodes that cannot directly sense each other. This intermediary function resolves the hidden-node problem while preserving efficient bandwidth utilization.
Data Source
AI summary
Disclosed are systems and methods which provide a busy tone or signal for use in communication collision avoidance in a wireless network, such as a WLAN, a cellular network, or other point-to-multipoint wireless network. An intelligent busy tone generator, upon the proper conditions, transmits a busy tone or signal to one or more wireless device which may otherwise be hidden from particular communications. According to embodiments the busy tone mimics a carrier sequence of an actual transmission to facilitate the wireless devices recognizing the channel as busy. Because the original uplink packet may be interfered by transmission of a busy tone carrier-sense sequence, embodiments are provided with interference cancellation capability. Interference cancellation circuitry of embodiments may operate in a plurality of modes, including a training mode (including an online training mode, an offline training mode, and a hybrid or combined mode) and an operating mode.