OFDM Demodulator Synchronization Using Reduced FFT Blocks
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Solution Overview
Problem
Current OFDM-demodulators face challenges in efficiently synchronizing with synchronization signals modulated with larger inverse FFT block lengths, leading to high energy consumption and complexity, which hinders the operation of energy-saving and intelligent sensor radio devices in cellular networks.
Innovation Solution
The proposed OFDM-demodulator reduces energy consumption and complexity by determining synchronization sequences using reduced FFT block lengths, allowing for efficient synchronization with synchronization signals modulated with larger inverse FFT block lengths, and reusing FFT blocks after synchronization is achieved, thereby enabling cost-effective and efficient access to cellular networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the OFDM-demodulator uses the same block length as the synchronization signal modulation (main block length), then synchronization accuracy is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent segments the synchronization process into two independent parts: (1) frequency offset estimation using small block length FFTs on individual OFDM symbols, and (2) synchronization sequence detection using the estimated frequency offset. This segmentation allows the device to avoid performing large block length FFTs while maintaining synchronization accuracy.
Solution Approach 2:
The patent introduces frequency offset estimation as an intermediary step between receiving the synchronization signal and detecting the synchronization sequence. By first estimating the frequency offset using small block length FFTs and then compensating for it before synchronization sequence detection, the system achieves accurate synchronization without requiring large block length processing capabilities.
2Measurement precision
If the OFDM-demodulator uses the same block length as the synchronization signal modulation (main block length), then synchronization accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent segments the synchronization process into two independent parts: (1) frequency offset estimation using small block length FFTs on individual OFDM symbols, and (2) synchronization sequence detection using the estimated frequency offset. This segmentation allows the device to avoid performing large block length FFTs while maintaining synchronization accuracy.
Solution Approach 2:
The patent introduces frequency offset estimation as an intermediary step between receiving the synchronization signal and detecting the synchronization sequence. By first estimating the frequency offset using small block length FFTs and then compensating for it before synchronization sequence detection, the system achieves accurate synchronization without requiring large block length processing capabilities.
3Device complexity
If the OFDM-demodulator uses reduced FFT block length, then energy consumption and complexity are reduced, but the ability to synchronize with larger block length modulation is compromised
Solution Approach 1:
The patent segments the synchronization process into two independent parts: (1) frequency offset estimation using small block length FFTs on individual OFDM symbols, and (2) synchronization sequence detection using the estimated frequency offset. This segmentation allows the device to avoid performing large block length FFTs while maintaining synchronization accuracy.
Solution Approach 2:
The patent changes the processing parameters by using small block length FFTs for frequency offset estimation instead of requiring large block length FFTs for the entire synchronization process. This parameter change enables devices with limited processing capabilities to synchronize with signals modulated using larger block lengths.
4Use of energy by moving object
If the OFDM-demodulator uses reduced FFT block length, then energy consumption and complexity are reduced, but processing capability is compromised
Solution Approach 1:
The patent segments the synchronization process into two independent parts: (1) frequency offset estimation using small block length FFTs on individual OFDM symbols, and (2) synchronization sequence detection using the estimated frequency offset. This segmentation allows the device to avoid performing large block length FFTs while maintaining synchronization accuracy.
Solution Approach 2:
The patent changes the processing parameters by using small block length FFTs for frequency offset estimation instead of requiring large block length FFTs for the entire synchronization process. This parameter change enables devices with limited processing capabilities to synchronize with signals modulated using larger block lengths.
Data Source
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AI summary
It is proposed an OFDM-demodulator (2000) for operating in a device (BS; UE) of a radio communications network (RCN). A first and second egress sample stream (n0,..., nM-1, o0, ..., oP-1) is determined in dependence on a first and second forward Fast Fourier Transform (FFTB1, FFTB2), respectively. It is determined a synchronization sequence (SS) in dependence on the first and second egress sample stream (n0,..., nM-1, oo,..., oP-1).