Carrier Frequency Offset Estimating Device for OFDM Systems
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Solution Overview
Problem
Carrier frequency offsets in wireless communication systems cause Inter-Carrier Interferences (ICIs), leading to inaccuracy and decreased efficiency due to discrepancies in oscillator frequencies between signal transmitters and receivers.
Innovation Solution
A carrier frequency offset estimating device comprising a transforming circuit, a cosine effect eliminating circuit, a model creating circuit, and an estimating circuit that transforms multi-carrier signals into single-carrier signals, eliminates cosine effects, creates linear data models, and estimates frequency offsets using these models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carrier signals are transmitted over communication channel, then wireless communication can be established, but frequency offsets occur due to oscillator mismatches causing Inter-Carrier Interferences
Solution Approach 1:
The patent applies preliminary action by estimating the frequency offset before demodulation processing. The system calculates the frequency offset between transmitter and receiver oscillators in advance, then applies compensation to prevent Inter-Carrier Interferences during the actual data reception, thereby maintaining communication accuracy without requiring retransmission.
2Productivity
If frequency offset estimation is performed to reduce ICIs, then communication efficiency improves, but system complexity increases due to additional processing circuits
Solution Approach 1:
The patent extracts the frequency offset estimation function as a separate, dedicated processing module that operates independently from the main data transmission and demodulation paths. This extraction allows the system to add necessary processing capability while keeping the core communication flow simple and efficient, minimizing the impact on overall system complexity.
Data Source
AI summary
A carrier frequency offset estimating device for estimating frequency offsets of a multi-carrier signal includes a transforming circuit, a cosine effect eliminating circuit, a model creating circuit, and an estimating circuit. The transforming circuit receives the multi-carrier signal and transforms the multi-carrier signal to single-carrier signals. The cosine effect eliminating circuit eliminates cosine effects in the single-carrier signals to form single-carrier signals without the cosine effects. The model creating circuit creates linear data models according to the single-carrier signals without the cosine effects. The estimating circuit estimates the frequency offsets of the multi-carrier signal according to the linear data models. A carrier frequency offset estimating system is also provided.