Multi-User Signal Detection With Iterative Interference Cancellation
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Solution Overview
Problem
Mobile satellite return link systems face challenges in delivering and processing high-rate data with limited bandwidth, as weak user signals are buried in multi-user access interference, making it difficult to detect multiple user signals simultaneously.
Innovation Solution
An advanced multi-user detection method for mobile satellite return link receivers, which includes iterative interference cancellation, dynamic or static energy burst detection, and adaptive channel estimation to sequentially decode and subtract user signals, enabling real-time detection even in scenarios with more users than the system's capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional spread-spectrum correlation receiver is used, then the system structure is simple, but only user signals with strong signal strength can be retrieved successfully while weak user signals are buried in multi-user access interference
Solution Approach 1:
The patent segments the detection process into multiple iterative stages. In each iteration, the receiver detects and cancels one dominant user signal, then proceeds to detect the next strongest signal in the remaining composite signal. This sequential segmentation allows weak signals to be detected after stronger interfering signals are removed, significantly improving measurement precision without requiring excessively complex hardware
Solution Approach 2:
The patent applies preliminary channel estimation and signal parameter detection before the main detection process. By预先 estimating channel characteristics and signal parameters, the receiver prepares accurate reference information that enables subsequent precise detection and cancellation of user signals, improving overall detection accuracy while maintaining reasonable system complexity
2Productivity
If the bandwidth is limited, then the system can operate within available spectrum resources, but the data rate and capacity are constrained and multiple user signals arrive superimposed and congested
Solution Approach 1:
The patent extracts individual user signals from the superimposed composite signal through iterative detection and cancellation. By sequentially extracting and removing detected user signals from the composite signal, the receiver can identify and decode multiple user signals that would otherwise be indistinguishable, effectively increasing the data rate within the limited bandwidth
Solution Approach 2:
The patent implements feedback through iterative interference cancellation. Each detected and cancelled user signal is subtracted from the composite signal, and the cancelled signal is fed back into the detection process to improve subsequent detections. This feedback mechanism enables the system to achieve higher effective capacity by continuously refining signal separation, allowing more users to communicate simultaneously within the limited bandwidth
3Adaptability or versatility
If iterative interference cancellation is implemented, then multiple user signals can be detected sequentially with different power profiles, but the processing complexity increases
Solution Approach 1:
The patent employs dynamic adaptation in the iterative detection process. The receiver dynamically adjusts detection parameters, cancellation depths, and processing steps based on the detected signal characteristics and interference levels in each iteration. This dynamic approach enables the system to handle varying numbers of users with different power profiles effectively, achieving high adaptability while optimizing processing complexity for each specific scenario
Data Source
AI summary
A method for detecting multi-user signals including conducting a first energy burst detection detecting a first plurality of user signals as a first energy burst, attempting to decode a user signal from the first plurality of signals within the first energy burst, cancelling out a first user signal from the first energy burst if the first user signal is successfully decoded from the first energy burst, determining a second user signal to be discarded if the second user signal is not successfully decoded from the first energy burst, conducting a second energy burst detection detecting a second plurality of signals as a second burst, and iteratively cancelling out the first user signal successfully decoded from the first energy burst from the second energy burst, wherein the second energy burst detection is conducted when all user signals within the first energy burst are either cancelled out or determined to be discarded.