Discrete Time Cancellation for RF Coexistence
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Solution Overview
Problem
Radio frequency communication systems face coexistence issues due to mutual desensitization effects between cellular and WiFi transceivers, where signal leakage from one transceiver interferes with the reception of the other, leading to degraded receiver sensitivity, and conventional high-Q bandpass filters are expensive and introduce insertion loss.
Innovation Solution
A mobile device with a discrete time cancellation circuit that generates observation signals to compensate for signal leakage by processing RF receive and transmit signals, using directional couplers to sense incoming and outgoing signals and adapt coefficients to reduce unwanted signal components, thereby enhancing receiver sensitivity and transmitter efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-Q bandpass filters are used to reduce signal leakage, then receiver sensitivity is improved, but device cost increases and insertion loss is introduced
Solution Approach 1:
The patent converts the harmful signal leakage into a useful observation signal by capturing the leaked RF signals through directional couplers and processing them through observation channels. This observed leakage signal is then used by the discrete time cancellation circuit to generate compensating signals that cancel the harmful effects, transforming the problem into a solution.
Solution Approach 2:
The patent introduces observation channels as intermediary components that capture and process the signal leakage before it reaches the victim receiver. These observation channels act as mediators between the aggressor transmitter and the victim receiver, enabling the cancellation circuit to compensate for the leakage effects without requiring high-Q filters.
2Reliability
If high-Q bandpass filters are used to reduce signal leakage, then receiver sensitivity is improved, but signal transmission efficiency deteriorates due to insertion loss
Solution Approach 1:
Instead of using filters that cause insertion loss, the patent converts the harmful leakage signal into a beneficial observation signal that enables active cancellation. The discrete time cancellation circuit generates compensating signals that restore the energy lost to leakage, improving both receiver sensitivity and transmission efficiency without the energy penalty of high-Q filters.
3Reliability
If discrete time cancellation circuits are used to reduce signal leakage, then receiver sensitivity is improved, but device complexity increases
Solution Approach 1:
The patent segments the signal processing function into separate observation channels and cancellation channels. The observation channels capture leakage signals while the cancellation channels process these observations to generate compensating signals. This segmentation allows the complex cancellation function to be integrated into existing transceiver architectures without requiring complete system redesign.
Solution Approach 2:
The observation channels serve multiple functions: they monitor signal leakage, provide feedback for cancellation, and enable coexistence management between different transceiver types. This multi-functionality reduces the need for separate dedicated components, thereby managing device complexity while achieving improved receiver sensitivity.
4Adaptability or versatility
If multiple transceivers operate simultaneously in a mobile device, then communication versatility is improved, but mutual desensitization occurs due to signal leakage
Solution Approach 1:
The patent implements feedback loops where observation channels continuously monitor signal leakage from aggressor transceivers and feed this information to discrete time cancellation circuits. The cancellation circuits then generate compensating signals in real-time to counteract the leakage, enabling multiple transceivers to operate simultaneously without mutual desensitization and maintaining both versatility and reliability.
Data Source
AI summary
Radio frequency (RF) communication systems with coexistence management are provided herein. In certain embodiments, a method of coexistence management in a mobile device includes processing a wireless local area network (WLAN) observation signal to generate WLAN observation data using a WLAN observation channel of a WLAN transceiver, processing an RF cellular receive signal to generate a digital baseband cellular receive signal using a cellular receive channel of a cellular transceiver, processing a cellular observation signal to generate cellular observation data using a cellular observation channel of the cellular transceiver, and compensating the digital baseband cellular receive signal for RF signal leakage based on the WLAN observation data and on the cellular observation data using a discrete time cancellation circuit of the cellular transceiver.