OTFS Channel Equalization for Inter-Carrier Interference
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Solution Overview
Problem
Current wireless communication networks face challenges in accommodating high data traffic and maintaining quality of service due to bandwidth limitations, particularly in scenarios with rapid channel variations caused by high mobility, leading to inter-carrier interference (ICI) in multicarrier systems.
Innovation Solution
The implementation of Orthogonal Time Frequency Space (OTFS) modulation, which divides the received signal into segments for channel estimation and equalization in the delay-dimension, effectively mitigating ICI by transforming the channel into a time-invariant 2D convolution in the delay-Doppler domain, allowing for improved robustness and performance without the need for ICI cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional OFDM modulation is used, then bandwidth efficiency is achieved, but inter-carrier interference occurs under rapid channel variations
Solution Approach 1:
The patent transforms the signal processing from traditional time-frequency domain to delay-Doppler domain. By applying 2D Fourier transform to map the time-frequency grid to delay-Doppler grid, the channel variations are converted into a time-invariant 2D convolution form, eliminating inter-carrier interference while maintaining bandwidth efficiency
Solution Approach 2:
The patent changes the fundamental parameters of signal representation by using delay-Doppler domain instead of time-frequency domain. This parameter transformation converts the time-varying channel into a time-invariant equivalent, allowing standard equalization techniques to work effectively without ICI cancellation
2Measurement precision
If channel segmentation is performed for equalization, then detection SNR is enhanced, but processing complexity increases
Solution Approach 1:
The patent divides the received OTFS signal along the delay dimension into multiple segments. Channel estimation and equalization are performed separately for each segment, which enhances detection SNR by reducing the impact of channel variations within each segment while managing processing complexity through localized processing
Data Source
AI summary
A wireless communication method for receiving an orthogonal time frequency space (OTFS) modulated signal includes receiving the OTFS signal over a wireless communication channel, dividing the receiving OTFS signal along a delay-dimension into a plurality of segments, performing, for each segment, channel estimation independent of channel estimation for other segments to generate a plurality of channel estimates, performing, for each segment, channel equalization using a corresponding channel estimate from the plurality of channel estimates to generate a channel-equalized symbol stream, and generating information bits from the channel-equalized symbol stream.