Anti-aliasing Channel Estimation for Multicarrier Signals
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Solution Overview
Problem
Existing multicarrier systems face channel aliasing issues, leading to inaccurate channel response estimation and compromised transmission quality due to aliased signals.
Innovation Solution
An anti-aliasing channel estimation apparatus and method that includes a synchronizing unit for clock recovery and data synchronization, a signal transforming unit using Fast Fourier Transform, an equalizing unit based on sampling phase and equalization coefficients, and a channel estimating unit to calculate channel and aliased signal responses for each subcarrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing channel estimation methods are used in multicarrier systems, then the estimation process is simple, but the channel response cannot correctly reflect the channel condition due to channel aliasing
Solution Approach 1:
The patent segments the channel response into two distinct components: the actual channel response and the aliased signal response. By separating these components mathematically, the system can estimate each independently using training sequences and sampling phase information, thereby improving estimation accuracy without requiring complete system redesign
Solution Approach 2:
The patent performs preliminary clock recovery and sampling phase estimation before channel estimation. This preliminary action provides the necessary sampling phase information that is then used to correctly separate and estimate the channel response and aliased signal response, preventing aliasing errors from propagating through the estimation process
2Reliability
If channel aliasing is not compensated, then the system operation is simple, but the transmission quality deteriorates due to inaccurate channel estimation
Solution Approach 1:
The patent uses training sequences transmitted at known positions to obtain feedback information about the sampling phase and channel characteristics. This feedback is then used to adjust the channel estimation process, compensating for aliasing effects and improving transmission reliability through iterative refinement
Solution Approach 2:
The patent introduces sampling phase information as an intermediary element that mediates between the received signal and the channel estimation. This intermediary provides the necessary correction factor to separate the aliased components from the true channel response, improving reliability without direct modification of the physical channel
Data Source
AI summary
An anti-aliasing channel estimation apparatus and method and a receiver where the anti-aliasing channel estimation method includes: performing clock recovery and data synchronization on a received multicarrier signal with channel aliasing, to obtain a synchronized time-domain signal and a sampling phase; calculating an estimation signal after passing through a channel and being aliased based on a training sequence and the sampling phase, and obtaining a channel response and an aliasing signal response of each subcarrier of the multicarrier signal based on the estimation signal and the frequency-domain signal. Therefore, channel estimation may be performed on the multicarrier signal with channel aliasing, influence of the channel aliasing on the bit error rate may be lowered, and transmission quality of the system may be improved.