Adaptive Antenna Switching for Interference-Resilient Receivers
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Solution Overview
Problem
Radio systems operating in the 2400-2483.5 MHz ISM band face significant interference from nearby radio signals, leading to spectral regrowth and decreased signal-to-noise ratio due to non-linear distortion in low-cost, low-power receivers, which existing antenna diversity methods fail to adequately address.
Innovation Solution
A communication device with an antenna system that switches between two signals differing in amplitude, using a processing unit to determine and select the signal quality, thereby detecting variations in neighboring interfering signals and choosing the state providing the best signal quality for processing, employing a multiplexer or switch with defined attenuation to reduce spectral regrowth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If antenna diversity selection is used to select the antenna with the strongest signal, then signal strength is improved, but spectral regrowth occurs due to non-linear distortion in the LNA when amplifying high-level interfering signals
Solution Approach 1:
The patent converts the harmful effect of strong interfering signals (which cause spectral regrowth) into a useful indicator for antenna selection. By detecting the presence of strong interfering signals on the currently selected antenna, the system uses this harmful condition to trigger a switch to a different antenna, thereby eliminating the spectral regrowth problem while maintaining strong desired signal reception.
Solution Approach 2:
The system implements feedback by continuously monitoring the signal quality and detecting interfering signals on the currently selected antenna. Based on this feedback, the antenna selection is dynamically adjusted to avoid antennas receiving strong interfering signals that would cause spectral regrowth, thus resolving the contradiction between signal strength and spectral regrowth.
2Use of energy by stationary object
If the receiver front-end is designed for low power and low cost, then power consumption and cost are reduced, but the receiver cannot handle high interference levels without non-linear distortion
Solution Approach 1:
The patent applies dynamics by making the antenna selection adaptive rather than static. The system dynamically switches between different antenna configurations based on real-time detection of interfering signals, allowing a low-power receiver to handle high interference levels by selecting antennas that are currently experiencing less interference, thus resolving the contradiction between low power consumption and interference susceptibility.
3Reliability
If RSSI-based antenna selection is used to select between attenuated and non-attenuated antenna paths, then reception is improved for nearby transmit sources, but interference introduced in the radio front-end itself is not addressed
Solution Approach 1:
The patent applies preliminary action by detecting interfering signals before they cause spectral regrowth in the LNA. The system proactively identifies the presence of strong interfering signals on the currently selected antenna and switches to a different antenna configuration in advance, preventing the harmful non-linear distortion from occurring in the first place.
Data Source
AI summary
The invention relates to a communication device (2) comprising an antenna system (4) provided with at least one antenna (6a, 6b, 6c) for receiving a radio signal and supplying a received radio signal to an output (8) of the antenna system, a low noise amplifier (10) for amplification of the received radio signal to obtain an amplified radio signal, and a processing unit (12) for processing the amplified radio signal. The antenna system (4) is configured to supply in a first state a first antenna signal as the received radio signal and in a second state second antenna signal as the received radio signal, wherein the first antenna signal and second antenna signal differ in amplitude. The antenna system is further configured to switch from state in response to a control signal (14) generated by the processing unit (12).