OFDM Radar Signal Windowing Without Cyclic Prefix
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing OFDM-based radar systems rely on cyclic prefixes (CP) for transmission and reception, which can limit performance and efficiency due to redundant guard intervals, and are not optimized for radar applications without commonality with communication systems.
Innovation Solution
A method and apparatus for transmitting and receiving OFDM signals without cyclic prefixes, using windowing techniques to select symbols for FFT processing based on estimated channel delays, allowing for channel estimation and improved radar performance without the need for CPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclic prefix (CP) is included in OFDM signal for traditional communication systems, then signal robustness against multipath interference is improved, but radar measurement precision and observation time efficiency deteriorate due to redundant guard intervals
Solution Approach 1:
The patent extracts and removes the cyclic prefix from the OFDM signal structure specifically for radar applications. By taking out the redundant CP portion that is unnecessary for radar's time-delay measurement functionality, the system achieves higher measurement precision and reduced observation time while maintaining signal integrity through alternative processing methods.
Solution Approach 2:
The patent segments the received OFDM signal into multiple symbols and applies windowing functions to select specific portions for FFT processing. This segmentation approach allows the system to process signals without CP while maintaining robustness by distributing the measurement across multiple processed segments.
2Reliability
If cyclic prefix (CP) is included in OFDM signal, then signal transmission reliability is improved, but observation time increases due to redundant guard intervals
Solution Approach 1:
The patent removes the cyclic prefix from the OFDM signal structure for radar applications, extracting only the necessary signal portions for processing. This elimination of redundant guard intervals directly reduces observation time while alternative processing methods maintain transmission reliability.
Solution Approach 2:
The patent enables continuous processing of OFDM symbols without the interruptions caused by CP removal and reassembly. By processing symbols continuously with windowing and selective FFT application, the system reduces total observation time while maintaining reliable signal transmission and reception.
3Measurement precision
If windowing is performed on received discrete time-domain signal to select symbols for FFT, then radar measurement precision is improved, but signal processing complexity increases
Solution Approach 1:
The patent applies windowing functions as a preliminary action before FFT processing to pre-select and prepare the appropriate signal portions. This preliminary windowing step simplifies the subsequent FFT processing by ensuring only relevant symbols are processed, thereby improving measurement precision while managing processing complexity through structured preparation.
Solution Approach 2:
The patent segments the received signal into discrete symbols and applies windowing to select specific segments for FFT processing. This segmentation approach improves measurement precision by focusing processing on relevant signal portions while managing complexity through systematic division and selective processing of signal segments.
Data Source
AI summary
A method of transmitting and receiving an orthogonal frequency division multiplexing (OFDM) signal for radio detection and ranging (radar) applications, and apparatuses performing the method are disclosed. The method includes receiving an OFDM signal in which a cyclic prefix (CP) is not included and converting the received OFDM signal to a received discrete time-domain signal through an analog-to-digital converter (ADC), selecting sub-carrier symbols to be input to a fast Fourier transform (FFT) from among all sub-carrier symbols included in the received discrete time-domain signal by performing windowing on the received discrete time-domain signal by a window that is based on an estimated value of a maximum delay that occurs potentially in a channel, converting the received discrete time-domain signal to a received frequency-domain signal by inputting the selected sub-carrier symbols to the FFT, and performing channel estimation based on the received frequency-domain signal.