Unequal Rate Interference Cancellation in Cross-Polarized Signals
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Solution Overview
Problem
Conventional digital signal processing systems are ineffective in removing co-channel interference when signals have different symbol or chipping rates, as they rely on the assumption that co-channel signals share the same rates, leading to data loss and inefficiency in communication systems dealing with cross-polarization and multi-directional signals.
Innovation Solution
The system receives and processes composite signals with different symbol or chipping rates, samples them at a sufficient rate to recover data, estimates and removes co-channel interference by aligning and decoupling signals, and uses feedback to adjust filters, enabling effective interference cancellation even when signals have disparate rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CPIC methods are used to remove co-channel interference, then interference cancellation is effective when signals have equal rates, but the system fails when signals have different symbol or chipping rates
Solution Approach 1:
The patent changes the fundamental parameter assumption from equal rates to different rates. It introduces rate differentiation as a key parameter, where the system identifies and processes signals with different symbol or chipping rates by estimating the interfering signal's characteristics and subtracting it from the composite signal, thereby resolving the contradiction between reliability and adaptability.
2Productivity
If signals are transmitted at different rates to increase bandwidth utilization, then communication efficiency improves, but co-channel interference corrupts data in each respective signal
Solution Approach 1:
The patent extracts the interfering signal component from the composite signal by estimating the interfering signal's parameters (amplitude, phase, rate) and subtracting it. This extraction process removes the harmful interference while preserving the desired signal, thereby maintaining data integrity while allowing different rate signals to coexist in the same frequency band.
Solution Approach 2:
The patent converts the harmful co-channel interference into a beneficial tool for identification and cancellation. By using the interference pattern itself to estimate and subsequently remove the interfering signal, the system transforms the problematic different-rate transmission into an opportunity for effective interference cancellation, thereby enabling high bandwidth utilization without data loss.
3Productivity
If cross-polarization is used to double bandwidth capacity, then frequency spectrum efficiency improves, but cross-channel interference corrupts signal data
Solution Approach 1:
The patent applies parameter changes by moving beyond the conventional assumption of equal symbol rates for cross-polarized signals. It enables the system to handle different symbol or chipping rates in cross-polarized signals by estimating and canceling interference, thereby maintaining both the bandwidth doubling benefit and the signal integrity despite cross-channel interference.
Data Source
AI summary
A method for receiving and removing co-channel interference from one or more received signals that comprise different symbol or chipping rates can comprise receiving a first composite signal and a second composite signal. The method can also comprise sampling the first composite signal and the second composite signal at a particular sampling rate that is sufficient to recover signal data from both the first composite signal and the second composite signal. Further, the method can comprise estimating from the second composite signal an estimated cross-coupled second signal within the first composite signal. The estimated cross-coupled second signal is estimated from at least the second composite signal at the particular sampling rate. Further still, the method can comprise recovering a substantially decoupled first data signal by removing at least a portion of the co-channel interference caused by the estimated cross-coupled second signal from the composite first signal.