Global Equalizer Self-Interference Cancellation for Hybrid MIMO
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Solution Overview
Problem
Hybrid multi-antenna systems face challenges in self-interference cancellation, particularly in full-duplex and cross-division duplex modes, due to complex nonlinear distortions from power amplifiers, which require accurate modeling and frequent updating of high-complexity models, making it difficult to maintain performance near the noise floor.
Innovation Solution
A global equalizer self-interference canceler is implemented using feedback signals from power amplifiers to estimate and subtract self-interference signals in hybrid multi-antenna systems, learning the channel between transmit and receive paths to replicate interference and improve signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-complexity models are used to accurately model power amplifier nonlinear distortions, then self-interference cancellation performance is improved, but device complexity and computational requirements increase
Solution Approach 1:
The patent segments the self-interference cancellation process into distinct functional blocks: feedback signal acquisition, channel estimation, distortion modeling, and signal subtraction. This modular approach allows each segment to be optimized independently, reducing overall system complexity while maintaining accuracy.
Solution Approach 2:
The patent creates a digital copy of the power amplifier's nonlinear distortion characteristics through channel estimation and modeling. This virtual model replicates the actual hardware behavior, allowing accurate self-interference cancellation without requiring complex real-time hardware processing.
2Reliability
If frequent updating of high-complexity models is performed, then self-interference cancellation performance is maintained, but processing time and computational load increase
Solution Approach 1:
The patent performs channel estimation and distortion modeling using previously acquired feedback signals before they are needed for cancellation. By preparing models in advance and storing them for later use, the system maintains up-to-date cancellation capabilities without requiring frequent real-time computations.
Solution Approach 2:
The patent implements a feedback mechanism where received signals are used to update channel estimates and distortion models. This continuous feedback loop automatically adjusts the cancellation parameters based on actual system behavior, maintaining reliability without manual intervention or excessive processing.
3Measurement precision
If additional hardware such as analog SIC circuitry is added, then self-interference cancellation capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces physical analog self-interference cancellation circuitry with digital signal processing techniques. By using software-based channel estimation, distortion modeling, and signal subtraction, the system achieves equivalent or superior cancellation performance without additional hardware components.
Solution Approach 2:
The patent introduces digital feedback signals as an intermediary between the power amplifier and the receive path. These feedback signals carry information about transmitted signal characteristics, enabling the system to compute and subtract self-interference without direct hardware coupling between transmit and receive chains.
Data Source
AI summary
A method includes transmitting, by a transceiver configured to concurrently transmit over multiple transmit paths and receive over multiple receive paths, one or more signals, the transceiver comprising multiple transmit antennas and multiple receive antennas. The method also includes, for at least one of the multiple receive antennas: receiving one or more feedback signals from one or more power amplifiers associated with the one or more transmitted signals; calculating one or more estimated self-interference (SI) signals based on the one or more feedback signals using an equalizer array comprising a predetermined channel model; and subtracting the one or more estimated SI signals from one or more receive signals received at the at least one receive antenna to obtain one or more residual signals.