Full-Duplex Interference Cancellation Using Orthogonal Training Signals
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Solution Overview
Problem
Full-duplex communication systems face significant challenges in mitigating self-interference (SI) and mutual-interference (MI) due to the simultaneous transmission and reception of signals, which can lead to reduced spectral efficiency and network performance.
Innovation Solution
The implementation of multi-stage self-interference cancellation and joint cancellation of mutual-interference and residual SI using orthogonal training signals transmitted during a shared over-the-air training period, allowing for accurate channel estimation and interference mitigation across full-duplex transmit/receive points in multi-cell networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex communication is implemented to double spectral efficiency, then spectral efficiency is improved, but self-interference and mutual-interference increase
Solution Approach 1:
The interference cancellation process is divided into multiple stages: first stage cancels self-interference using locally generated training signals, while second stage cancels mutual-interference from other cells using orthogonally multiplexed training signals from neighboring TRPs. This segmentation allows systematic handling of different interference types.
Solution Approach 2:
Orthogonal training signals are transmitted during a dedicated training period before actual data transmission begins. This preliminary action enables channel estimation and interference cancellation parameters to be established in advance, allowing the system to operate in full-duplex mode with interference mitigation already configured.
2Object-generated harmful factors
If multi-stage interference cancellation is implemented, then interference levels are reduced, but device complexity increases
Solution Approach 1:
The same orthogonal training signals serve multiple purposes: they enable channel estimation for mutual-interference cancellation, provide reference for self-interference cancellation, and facilitate time-of-arrival estimation. This multi-functionality reduces the need for separate signaling mechanisms.
Solution Approach 2:
Orthogonal training signals act as intermediaries between transmit and receive operations. These known signals are transmitted alongside data, enabling the receiver to estimate channels and reconstruct interference components without directly observing the interference itself, simplifying the cancellation process.
3Measurement precision
If orthogonal training signals are transmitted during shared training period, then channel estimation precision is improved, but training period duration increases
Solution Approach 1:
The training periods of multiple transmit/receive points are merged into a shared training period. Orthogonal training signals from different TRPs are transmitted simultaneously during this common period, allowing parallel channel estimation without sequential training overhead, thus reducing total training time while maintaining precision.
Solution Approach 2:
Orthogonal training signals are transmitted periodically during the shared training period at predetermined intervals. This periodic transmission allows channel estimation to be performed at multiple time points, improving estimation accuracy through temporal averaging while keeping the overall training duration constrained.
Data Source
AI summary
Techniques and architectures for multi-stage cancellation of self-interference (SI) and joint cancellation of mutual-interference (MI) and residual SI in signals received by devices of a full-duplex multi-cell network are disclosed. In various examples, channel estimations and interference cancellation operations are performed utilizing multiple orthogonal training signals transmitted by network devices during a common over-the-air training period. Training signals derived from the orthogonal training signals during transmission are utilized to generate SI estimation information and perform at least a first SI cancellation operation on a received signal that includes at least first and second orthogonal training signals. The received signal and orthogonal training signals are then used to estimate a MI channel impulse response and a (residual) SI channel impulse response for use in joint MI/SI cancellation operations on further received signals. Details regarding the design of the orthogonal training signals and a unique system-level delay calibration procedure are also provided.