Cyclic Prefix Correlation for Interference Detection in Cognitive Radio
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Solution Overview
Problem
Current communication systems using cognitive radio technology face challenges in determining interference levels between primary and secondary networks, particularly in OFDM schemes, where existing methods lack effective interference detection mechanisms.
Innovation Solution
An apparatus and method that utilize a signal receiver, correlator, and interference determination unit to compute correlation values of cyclic prefixes in signals from both networks, allowing for the determination of interference levels and identification of signal existence without separate time slots, using a correlator to compute correlation values of cyclic prefixes and determining interference based on these values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cognitive radio technology is used to recycle frequency resources, then frequency resource utilization is improved, but interference determination between primary and secondary networks becomes difficult
Solution Approach 1:
The patent extracts the cyclic prefix portion from the OFDM signal and uses it as a reference for interference detection. By separating and analyzing only the cyclic prefix (which contains distinctive temporal patterns) rather than the entire signal, the system can effectively determine interference presence and level between primary and secondary networks, resolving the contradiction between efficient frequency reuse and reliable interference detection.
Solution Approach 2:
The patent performs preliminary analysis of the cyclic prefix before full signal processing. The cyclic prefix is analyzed in advance to determine interference conditions, allowing the system to make interference determination decisions based on this preliminary information. This enables timely suspension or adjustment of secondary network operations before full interference occurs.
2Measurement precision
If separate time slots are allocated for signal identification, then signal detection accuracy is improved, but time efficiency deteriorates
Solution Approach 1:
The patent merges the signal identification function with the existing OFDM signal processing structure. Instead of allocating separate time slots for signal detection, the system identifies signals by analyzing the cyclic prefix portions that are already present in the received signal. This integration eliminates the need for additional time slots while maintaining detection accuracy, as the cyclic prefix analysis provides sufficient information for interference determination.
Data Source
AI summary
An interference determination apparatus, including a signal receiver to receive a first signal of a primary network and a second signal of a secondary network; a correlator to compute a correlation value of a first cyclic prefix included in the first signal and a correlation value of a second cyclic prefix included in the second signal; and an interference determination unit to determine an interference level or whether the interference occurs between the primary network and the secondary network, using the correlation value of the first cyclic prefix and the correlation value of the second cyclic prefix.