Iterative CCI Detection for Multibeam Satellite Receivers
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Solution Overview
Problem
Multibeam satellite systems face significant challenges in mitigating Co-Channel Interference (CCI) due to memory effects, which are exacerbated by aggressive frequency reuse, leading to performance degradation and increased complexity in existing receivers.
Innovation Solution
A modular receiver-based CCI mitigation system that processes composite signals at the user terminal, partitioning interferer symbols into dominant and non-dominant groups to generate A Posteriori Probabilities, using a Soft-In Soft-Out (SISO) Iterative Divide-And-Conquer (IDAC) detector to effectively handle memory effects without exponential complexity increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aggressive frequency reuse (reuse factor 1 or 2) is employed to increase spectral efficiency, then system capacity and spectral efficiency are improved, but co-channel interference severity increases dramatically
Solution Approach 1:
The patent segments the interference mitigation task into multiple detection stages: first detecting desired symbols, then using those detections to detect interfering symbols, and iteratively refining both. This segmentation allows the system to handle severe CCI by breaking down the complex detection problem into manageable steps, enabling aggressive frequency reuse while maintaining performance
Solution Approach 2:
The patent implements iterative feedback between desired symbol detection and interferer symbol detection. Each detection round uses the results from the previous round to improve subsequent detections, allowing the system to converge to near-capacity performance even under severe CCI conditions with aggressive frequency reuse
2Adaptability or versatility
If receiver-based CCI compensation is implemented to overcome gateway limitations, then feasibility and adaptability are improved, but receiver complexity increases
Solution Approach 1:
The receiver is segmented into modular functional blocks: a desired symbol detector, an interferer symbol detector, and an iterative detection controller. This segmentation makes the complex receiver easier to implement and maintain while preserving the adaptive capabilities needed for severe CCI environments
Solution Approach 2:
The patent implements dynamic adaptation through iterative detection, where the receiver adjusts its detection parameters and strategies based on the detected signal characteristics and interference levels. This dynamic behavior enables the receiver to adapt to varying CCI conditions without requiring overly complex fixed architecture
3Measurement precision
If iterative detection with memory effects compensation is used to achieve near-capacity performance, then detection accuracy is improved, but computational complexity increases exponentially
Solution Approach 1:
The patent segments the iterative detection process into distinct phases: initial desired symbol detection, interferer symbol detection using detected desired symbols, and iterative refinement. This segmentation prevents exponential complexity growth by processing symbols in manageable groups rather than considering all possible symbol combinations simultaneously
Solution Approach 2:
The patent performs preliminary detection of desired symbols before detecting interferer symbols. This preliminary action provides a foundation for subsequent interferer detection, reducing the computational burden by eliminating the need to simultaneously consider all symbol detections from scratch in each iteration
Data Source
AI summary
A communications apparatus to receive a composite signal including a desired signal and interferer signals, where the desired signal may include desired symbols and the interferer signals may include interferer symbols. The system may include N frameworks, each framework may include a detector to partition the desired symbols and the interferer symbols based on an interference severity into a dominant group and a non-dominant group, and to generate A Posteriori Probabilities (APP) of the desired symbols and the interferer symbols. The detector of each of the N frameworks generates the APP based on a feedback of a priori probabilities from each of the N frameworks.