MIMO Backscatter Signal Detection With Spatial Interference Filtering
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Solution Overview
Problem
Existing MIMO readers face challenges in efficiently communicating with backscattering devices due to high direct link interference, which overwhelms the backscattered signal, especially in bi-static setups, and the need for expensive full-duplex MIMO technology.
Innovation Solution
A MIMO reader with two antenna panels employs spatial filter coefficients to minimize interference, allowing the detection of backscattered signals by selecting coefficients that reduce direct link interference and using beamforming techniques to transmit and receive signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bi-static MIMO reader setup is used to avoid full-duplex technology, then device complexity and cost are reduced, but direct link interference from transmitting panel to receiving panel increases and overwhelms the backscattered signal
Solution Approach 1:
The patent applies spatial filtering to convert the harmful direct link interference into a manageable signal component. By designing spatial filter coefficients that exploit the known structure of direct link propagation, the system separates the strong direct interference from the weak backscattered signal, effectively converting the interference problem into a solvable signal separation task
Solution Approach 2:
The patent changes the spatial domain parameters by applying spatial filter coefficients to the received signals. These coefficients transform the signal space to separate the direct link component from the backscattered component, allowing the receiver to extract useful information despite the presence of strong direct interference
2Reliability
If spatial filter coefficients are applied to minimize direct link interference, then backscattered signal detection is improved, but signal processing complexity increases
Solution Approach 1:
The patent performs preliminary channel estimation and spatial filter coefficient calculation before actual signal detection. By pre-computing the spatial filters based on channel characteristics and then applying them to the received signals, the system reduces the complexity of real-time processing while maintaining reliable backscattered signal detection
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables reliable detection of low-energy signals from backscattering devices with minimal direct link interference, facilitating the use of low-noise amplifiers and improving communication reliability.
Implementation Method 1
transmitting, from the first antenna panel and whilst applying the selected first spatial filter coefficients, a first signal
Implementation Method 2
By varying this impedance, the backscattering device can affect the properties of the wave that is reflected (backscattered) when the device is illuminated by RF energy
Implementation Method 3
selecting, for the first antenna panel, first spatial filter coefficients with an object to minimize interference from the first antenna panel towards the second antenna panel over a radio propagation channel
Data Source
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AI summary
There is provided mechanisms for detecting a signal communicated by a backscattering device. A method is performed by a MIMO reader that comprises a first antenna panel and a second antenna panel. The method comprises selecting, for the first antenna panel, first spatial filter coefficients with an object to minimize interference from the first antenna panel towards the second antenna panel over a radio propagation channel. The method comprises transmitting, from the first antenna panel and whilst applying the selected first spatial filter coefficients, a first signal. The method comprises receiving, at the second antenna panel, a backscattered signal component of the first signal as backscattered by the backscattering device. The backscattered signal component comprises the signal communicated by the backscattering device. The MIMO reader thereby detects the signal communicated by the backscattering device.