Cyclic Prefix Modification for Signal Separation
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Solution Overview
Problem
In telecommunications systems, especially those using xDSL or OFDM techniques, separating data signals received by a transmission/reception device is challenging due to interference from other signals, requiring methods to identify and isolate specific signals without increasing network equipment costs or complexity.
Innovation Solution
Modifying the size of the cyclic prefix in data blocks before transmission allows for the separation of data signals using a cyclic autocorrelation function, enabling effective identification and interference correction without additional processing or equipment modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a blind identification method using precoding algorithms is applied to separate data signals, then signal separation capability is improved, but device complexity and implementation cost increase
Solution Approach 1:
The patent changes the parameter of cyclic prefix length in data blocks to create distinctive cyclostationary characteristics for different data signals. By modifying this structural parameter rather than applying complex precoding algorithms, the system achieves signal separation capability while avoiding increased device complexity. The cyclic prefix length modification creates unique autocorrelation signatures that enable blind identification without requiring additional processing equipment.
2Measurement precision
If precoding sequences are applied to modify cyclostationary periodicity for signal separation, then data signal identification is improved, but implementation complexity increases
Solution Approach 1:
The patent applies preliminary action by modifying the cyclic prefix length during the data block preparation stage, before transmission. This preliminary modification of the data structure embeds the identification characteristic directly into the transmitted signal, eliminating the need for complex real-time precoding operations at transmission and simplifying the overall implementation while maintaining data signal identification capability.
3Device complexity
If cyclic prefix size is modified before transmission, then signal separation is simplified, but data block structure changes
Solution Approach 1:
The patent accepts the necessary change in data block structure (cyclic prefix length) as a trade-off to achieve simplified signal processing. By varying this parameter across different data blocks or signals, the system creates distinguishable autocorrelation patterns that enable straightforward signal separation using cyclic autocorrelation functions, reducing overall processing complexity despite the structural modification.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method simplifies signal processing, reduces interference noise, and maintains data integrity without altering the transmitted data, making it applicable to existing systems and cost-effective.
Implementation Method 1
modifying the cyclostationary periodicity of the data signals carried by the links of the system
Implementation Method 2
applying a cyclic autocorrelation function. Such a function is a second-order statistical function which, when applied to one or more data signals, induces source effects related to the cyclostationary periodicity
Data Source
Figure 1A~2B
Figure 3~7
Figure 5A~5B
AI summary
A method is provided for sending at least a first data signal and a second data signal, the data being divided into data blocks of fixed size including a header field of predetermined size, the data signals being sent to at least one data processing device adapted to apply a cyclic autocorrelation function with parameter k enabling the first and second data signals to be identified. The value of the parameter k is a function of a ratio between the size of the data blocks and the predetermined size of the header field. The method includes modifying the size of the header field of the data blocks before sending the first data signal, the value of the parameter k and the size of the data blocks remaining unchanged. A method is also provided for processing signals sent in accordance with the sending method.