Frequency Offset Acquisition in TDS-OFDM Multipath Environments
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Solution Overview
Problem
Conventional frequency offset estimation methods for TDS-OFDM systems are inaccurate in multipath transmission environments, leading to unreliable compensation.
Innovation Solution
A method and apparatus that shift a sequence signal by multiple frequencies in the frequency domain to generate shifted sequence signals, allowing for the determination of a reliable frequency offset value between a transmitter and a receiver, utilizing a two-phase operation to derive and fine-tune the estimated frequency offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional frequency offset estimation method using PN sequence and loop filter is used, then the system can operate in simple transmission environments, but the frequency offset estimation becomes extremely inaccurate in multipath transmission environments
Solution Approach 1:
The patent segments the received signal into multiple frequency-shifted versions and processes each separately. By dividing the frequency offset estimation into multiple discrete frequency shifts and comparing results, the method achieves accurate estimation in multipath environments where conventional single-path methods fail.
Solution Approach 2:
The patent changes the frequency parameter of the received signal by applying multiple different frequency shifts. This parameter transformation allows the system to identify the correct frequency offset by comparing shifted versions, making the estimation robust against multipath interference that confuses conventional methods.
2Measurement precision
If frequency shifting operation is performed at multiple different frequencies, then the frequency offset estimation accuracy is improved, but the computational complexity and processing time increase
Solution Approach 1:
The patent applies partial frequency shifting by selecting a limited number of discrete frequency shifts rather than continuous scanning. This partial action approach achieves sufficient estimation precision without requiring exhaustive processing, balancing accuracy with computational feasibility.
Data Source
AI summary
A frequency offset acquisition method includes: receiving a specific sequence signal transmitted through a channel; shifting a frequency of the specific sequence signal at a plurality of different frequencies in frequency domain to thereby generate a plurality of shifted sequence signals respectively; and determining an estimated frequency offset value between a transmitter and a receiver according to the shifted sequence signals.