Blind Signal Separation Using Unique Filter Tagging in MIMO Systems
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Solution Overview
Problem
In MIMO systems, blind identification of CSI results in multiple solutions with permutations, making it impossible to assign separated source signals to specific sources without additional information, and conventional methods reduce system throughput or require redundant data transmission.
Innovation Solution
The method involves filtering and tagging signals with unique filters at the transmitter and using inverse filters at the receiver to restore signal properties, allowing for permutation-free separation by adjusting gains to remove interfering signals within the same frequency band or time slot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If training data is used to estimate channel state information in MIMO systems, then signal separation accuracy is improved, but system throughput is reduced
Solution Approach 1:
The patent applies preliminary action by pre-filtering source signals with unique filters before transmission. This tagging process prepares the signals in advance so that they can be separated without requiring training data during reception, thereby eliminating the throughput penalty associated with training sequences while maintaining separation accuracy
Solution Approach 2:
The patent introduces unique filters as intermediary elements between the source signals and the transmission channel. These filters act as mediators that embed identifying characteristics into each signal, enabling the receiver to separate mixed signals without needing training data, thus resolving the contradiction between separation accuracy and throughput
2Productivity
If complete blind identification is used to separate mixed signals, then system throughput is maintained, but permutation ambiguity prevents correct source signal assignment
Solution Approach 1:
The patent applies local quality by assigning unique local characteristics (unique filters) to each source signal before transmission. This creates distinct local properties in the mixed signals that allow the receiver to identify and assign each separated signal to its correct source, eliminating permutation ambiguity while maintaining blind operation and throughput efficiency
3Loss of information
If redundant data transmission is used to resolve permutation ambiguity, then source signal assignment accuracy is improved, but system throughput is reduced
Solution Approach 1:
The patent uses preliminary action by embedding unique filter tags in source signals before transmission. This advance preparation provides the necessary identification information within the signal itself, eliminating the need for redundant data transmission while maintaining accurate source signal assignment and preserving system throughput
Data Source
AI summary
A method of blindly separating a signal, wherein, for at least one source, a filter uniquely defined for a source is determined for each source, the method comprising the steps of: applying an inverse filter corresponding to inverse of the filter to one or more of multiple outputs of the received signal so as to restore property of the corresponding source; and adjusting gain of each of outputs which have been filtered by the inverse filter, under constraint that a sum of weighted multiplexed filtering output signals has the same property as an original signal of the corresponding source, in order to remove other sources or interfering signals which occupy the same frequency band or transmission time interval.