Full Duplex Reconfigurable Antenna Self-Interference Cancellation
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Solution Overview
Problem
Full-duplex wireless communications face limitations in managing self-interference signals, particularly in transceivers where antenna separation is limited, hindering the potential for increased spectral efficiency and data rates.
Innovation Solution
A full-duplex reconfigurable antenna system with a multi-reconfigurable antenna (MRA) capable of dynamically changing its radiation patterns, polarization, and operating frequency, combined with a heuristic-based approach to reduce training overhead, achieves significant passive self-interference suppression and enhances the Signal-of-Interest to Interferer Ratio (SIR) for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex mode is used to double spectral efficiency, then data transmission rate is improved, but self-interference signals are generated that degrade signal quality
Solution Approach 1:
The patent segments the self-interference cancellation process into three distinct stages: passive suppression (physical isolation and antenna design), active cancellation (analog domain interference subtraction), and digital cancellation (digital signal processing). This multi-stage segmentation allows each method to address specific aspects of self-interference, achieving cumulative cancellation效果 of up to 95 dB while maintaining full-duplex spectral efficiency.
Solution Approach 2:
The patent implements preliminary self-interference cancellation measures before the receive signal processing. Passive suppression techniques (antenna isolation, shielding) are applied first to reduce the interference power level, followed by active cancellation that subtracts a scaled version of the transmit signal from the receive signal. This preliminary action prevents the self-interference from overwhelming the weak received signals, enabling full-duplex operation.
2Object-generated harmful factors
If antenna separation is increased to reduce self-interference, then signal quality is improved, but device size and complexity increase
Solution Approach 1:
The patent changes multiple antenna parameters simultaneously to achieve self-interference suppression without increasing physical separation. This includes adjusting antenna polarization (e.g., orthogonal polarizations for TX and RX), modifying radiation patterns through beamforming, and tuning operating frequencies. These parameter changes enable effective self-interference cancellation in compact transceiver designs, achieving 45 dB passive suppression with minimal antenna separation.
3Object-generated harmful factors
If reconfigurable antenna is used to dynamically adjust radiation patterns, then self-interference suppression is improved, but training overhead increases
Solution Approach 1:
The patent applies partial reconfiguration of antenna parameters rather than exhaustive optimization. Instead of continuously adjusting all antenna parameters, the system selectively reconfigures specific parameters (such as polarization or beam direction) based on current channel conditions and interference levels. This partial action approach achieves sufficient self-interference suppression (45 dB SIR gain) while minimizing training overhead and maintaining low latency.
Data Source
AI summary
Embodiments of transceivers with one or more reconfigurable antennas are described. In one embodiment, a reconfigurable antenna transceiver includes a transmit chain, a receive chain, and a reconfigurable antenna having a plurality of reconfigurable modes. The transceiver may also include an antenna controller configured to set a mode of the reconfigurable antenna. According to other aspects, the transceiver may also include a signal processor configured to transmit a set of training symbols during a training interval. The antenna controller may be further configured to select a respective mode of the reconfigurable antenna for each training symbol in the set of training symbols. Additionally, the antenna controller may be configured to calculate a received Signal-of-Interest to Interferer Ratio (SIR) for each training symbol of the set of training symbols. In this context, a system utilizing a reconfigurable antenna may achieve significant rate improvement compared to half-duplex systems.