RF Front-End Cancellation Paths for Full-Duplex Radios
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Full duplex radio communication systems experience significant self-interference due to the system's own transmission interfering with its own reception, leading to diminished data throughput and reduced signal-to-noise ratio (SNR).
Innovation Solution
Implementing a transceiver with a main transmitter and canceller transmitter to generate RF transmit and cancellation signals, amplified by power amplifiers, and splitting these signals into multiple paths for cancellation, combined with the received signal in both the RF and digital domains to cancel self-interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex radio technology is used to double spectral efficiency, then spectral efficiency is improved, but self-interference from the system's own transmission interferes with reception, reducing data throughput
Solution Approach 1:
The patent applies preliminary anti-action by generating a cancellation signal that is the inverse of the expected self-interference signal before it reaches the receiver. The canceller transmitter creates an RF cancellation signal that, when combined with the received signal, pre-neutralizes the self-interference from the main transmitter, allowing the receiver to detect the desired signal without degradation.
Solution Approach 2:
The patent introduces an intermediary cancellation signal path that mediates between the harmful self-interference and the desired received signal. The canceller transmitter and canceller receiver create an intermediate cancellation path that generates and processes the cancellation signal, which then combines with the received signal to eliminate the harmful self-interference component.
2Duration of action of moving object
If the same frequency is used for continuous transmitting and receiving, then continuous communication capability is improved, but the transmit signal interferes with the receive signal, reducing signal-to-noise ratio
Solution Approach 1:
The system applies preliminary anti-action by continuously generating cancellation signals that preemptively counteract the self-interference. The canceller transmitter continuously produces RF cancellation signals that are combined with the received signal before processing, ensuring that the transmit signal does not degrade the signal-to-noise ratio of the received signal.
Solution Approach 2:
The patent maintains continuity of useful action by enabling simultaneous continuous transmission and reception on the same frequency. The cancellation mechanism operates continuously alongside the main transmit and receive paths, allowing the system to maintain uninterrupted full-duplex communication without sacrificing signal quality.
3Productivity
If self-interference cancellation is implemented to maintain data throughput, then data throughput is improved, but the system complexity increases with additional transmitters, receivers, and signal processing paths
Solution Approach 1:
The patent applies segmentation by dividing the radio system into distinct functional segments: a main transmitter-receiver path and a separate canceller transmitter-receiver path. This segmentation allows the self-interference cancellation function to be implemented as a modular addition rather than requiring complete system redesign, managing complexity through functional separation.
Solution Approach 2:
The canceller transmitter and canceller receiver serve multiple functions: they generate cancellation signals, process received signals, and combine outputs to eliminate self-interference. This multi-functionality reduces the need for additional dedicated components, managing system complexity by having the cancellation path perform multiple roles in the overall interference mitigation process.
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Apparatus and methods for self-jamming cancellation in full duplex radios are disclosed herein. In certain embodiments, an RF front-end system includes a main power amplifier that amplifies an RF transmit signal from a main transmitter of a transceiver and a canceller power amplifier that amplifies an RF cancellation signal from a canceller transmitter of the transceiver. The RF front-end system operates to split the amplified RF cancellation signal into two or more cancellation signals including a first cancellation signal that is combined with an RF receive signal and a second cancellation signal that is combined with a sensed transmit signal from an output of the main power amplifier. The RF receive signal and the first cancellation signal are combined and provided to a main receiver of the transceiver, while the sensed transmit signal and the second cancellation signal are combined and provided to a canceller receiver of the transceiver.