WLAN Jammer and Interference Canceller for Hidden Node Conflict Resolution
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Solution Overview
Problem
In wireless local area networks (WLANs), interference between STAs (stations) can lead to signal conflicts and reduced throughput due to long distances or obstructions, causing hidden node problems where STAs cannot detect each other's signals, resulting in simultaneous transmissions and interference.
Innovation Solution
A wireless device with a receiver, jammer, and interference canceller is used to detect WLAN signals and send interference signals on the same channel, generating a reconstruction signal to cancel interference, ensuring proper signal reception without additional air interface resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If STAs send signals simultaneously due to hidden node problem, then channel utilization increases, but signal interference occurs and reception reliability deteriorates
Solution Approach 1:
The AP sends a preliminary interference signal before receiving the STA signal to preemptively occupy the channel. This preliminary action prevents other STAs from transmitting simultaneously, thereby maintaining high channel utilization while ensuring reliable signal reception by eliminating potential interferers.
Solution Approach 2:
The patent converts the harmful self-interference signal (which would normally degrade reception) into a beneficial channel reservation mechanism. By intentionally transmitting an interference signal and then canceling it at the receiver, the system benefits from channel occupancy notification to other STAs, preventing collisions and improving overall reception reliability.
2Reliability
If AP sends interference signal to prevent collisions, then signal reception reliability improves, but device complexity increases due to additional jammer and interference canceller components
Solution Approach 1:
The patent merges the interference signal generation function into the existing transmitter chain and the interference cancellation function into the existing receiver chain. By reusing existing hardware components for dual purposes, the system achieves reliable signal reception without proportionally increasing device complexity.
Solution Approach 2:
The transmitter is designed to serve dual functions: normal data transmission and interference signal generation for channel reservation. Similarly, the receiver performs both standard signal reception and interference cancellation. This multi-functionality reduces the need for dedicated separate components, thereby limiting the increase in device complexity while maintaining high reliability.
3Reliability
If interference signal is sent continuously to maintain channel occupancy, then signal reception reliability is maintained, but energy consumption increases
Solution Approach 1:
Instead of continuous interference signal transmission, the system employs periodic transmission synchronized with the expected STA transmission times. The interference signal is sent only during critical reception periods when STA signals are expected, and remains inactive during other times, thereby maintaining reception reliability while significantly reducing energy consumption compared to continuous transmission.
Data Source
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AI summary
A wireless device and a wireless local area network signal receiving method is provided. The wireless device includes a receiver, a jammer, an interference canceller, a first antenna, and a second antenna. The receiver is connected to the first antenna, the jammer is connected to the second antenna, an input end of the interference canceller is connected to the second antenna, and an output end of the interference canceller is connected to the first antenna. The receiver is configured to detect a wireless local area network signal; the jammer is configured to send, by using the second antenna, an interference signal on a channel on which the wireless local area network signal is located; and the interference canceller is configured to: generate, based on the interference signal, a reconstruction signal used to cancel the interference signal received by the first antenna, and provide the reconstruction signal at the output end. This avoids a wireless local area network signal conflict, and occupies no additional air interface resource. In addition, interference in the receiver can be canceled in a process of sending the interference signal, thereby ensuring that the receiver can properly receive the wireless local area network signal.