Pre-equalizer Phase Shift Estimation for 60 GHz Signal Demodulation
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Solution Overview
Problem
High-frequency wireless communication systems, such as those operating at 60 GHz, face significant challenges in channel estimation and signal demodulation due to severe phase noise and low signal-to-noise ratio, which degrade the accuracy of frequency domain equalization and limit the modulation order of radio receivers.
Innovation Solution
The implementation of a pre-equalizer and optional post-equalizer in radio receivers to estimate and correct phase shifts within the signal, utilizing known signal parts like Golay sequences and guard intervals to derotate data blocks before frequency domain equalization, thereby reducing the impact of phase noise on channel estimation and demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single equalizer is used for frequency domain equalization, then the device complexity is low, but the measurement precision of channel estimation and signal demodulation deteriorates due to phase noise
Solution Approach 1:
The equalization process is divided into two separate stages: a first equalizer performs initial frequency domain equalization, and a second equalizer performs subsequent equalization on the output of the first equalizer. This segmentation allows each equalizer to be optimized for specific functions, with the first equalizer handling coarse correction and the second equalizer refining the estimation, thereby improving overall measurement precision without requiring a single overly complex equalizer structure
Solution Approach 2:
The first equalizer performs preliminary equalization to correct the most significant channel distortions and phase shifts before the signal is processed by the second equalizer. This preliminary action reduces the burden on the second equalizer and improves the overall channel estimation accuracy by addressing major impairments in advance
2Productivity
If the modulation order is increased to transmit more information, then the productivity increases, but the reliability decreases due to severe phase noise and low signal-to-noise ratio at 60 GHz
Solution Approach 1:
The dual equalizer structure provides iterative refinement where the output of the first equalizer feeds into the second equalizer, which can further correct residual errors. This feedback-like progressive correction mechanism enhances the reliability of signal demodulation by continuously improving the signal quality through multiple processing stages, enabling more robust higher-order modulation schemes
Data Source
AI summary
A device includes an input configured to receive a signal, wherein the signal includes at least one data block and a plurality of signal parts known to the device, a first signal part at the beginning of the data block and a second signal part at the end of the data block. The device further includes an equalizer and a pre-equalizer coupled between the input and the equalizer, wherein the pre-equalizer is configured to estimate a phase shift between the plurality of signal parts.