CPS-OTFS MIMO Transceiver for High-Speed Mobility
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Solution Overview
Problem
Current wireless MIMO transceivers face challenges in maintaining seamless communication during high-speed mobility due to out-of-band radiation, high peak-to-average power ratio (PAPR), and increased bit error rate, exacerbated by time-varying channels and high computational complexity, making them unsuitable for 5G networks with high mobility applications.
Innovation Solution
A wireless MIMO transceiver system that employs Circularly Pulse Shaped Orthogonal Time Frequency Space (CPS-OTFS) signals, using predefined algorithms to generate and process time-frequency signals through multiple antennas, with N-point IFFT and FFT transformations, to reduce waveform dispersion and computational complexity, while controlling inter-symbol and inter-carrier interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MIMO transceivers use rectangular pulse modulation for high-speed mobility communication, then the system can operate under dynamic channel conditions, but it generates very high out-of-band radiation and high PAPR causing increased bit error rate
Solution Approach 1:
The patent changes the waveform parameter from rectangular pulse to circular pulse modulation. This parameter change fundamentally alters the spectral characteristics, reducing out-of-band radiation and PAPR while maintaining communication reliability under high-speed mobility conditions.
Solution Approach 2:
The patent employs circular pulse shaping instead of rectangular pulse shaping. The circular waveform has smoother transitions and better spectral containment properties, which directly reduces out-of-band radiation and PAPR compared to the sharp edges of rectangular pulses.
2Speed
If 5G-NR uses multi-numerology OFDM system with increased sub-carrier bandwidth to combat doppler spread, then the system can support higher vehicular speed scenarios, but proportional decrement of Cyclic Prefix length induces interference when delay and doppler spreads are significant
Solution Approach 1:
The patent replaces the conventional OFDM mechanism with OTFS (Orthogonal Time Frequency Space) modulation. This substitution fundamentally changes how the system handles time-varying channels by transforming the problem domain, allowing the system to maintain performance under high doppler spread without suffering from CP length limitations.
Solution Approach 2:
The patent transitions from frequency-domain modulation (OFDM) to time-frequency-space domain modulation (OTFS). This dimensional change allows the system to exploit the time-frequency plane for signal transmission, providing robustness against both delay spread and doppler spread simultaneously.
3Reliability
If conventional MIMO transceivers use matched filter-based receiver with OTFS to address inter-symbol and inter-carrier interference, then the interference issues are mitigated, but the associated computational complexity makes the solution impractical
Solution Approach 1:
The patent employs channel sounding signals and pilot signals that replicate the structure of data signals. By using these copies for channel estimation and equalization, the system can achieve effective interference cancellation without requiring complex real-time channel inversion operations, thus reducing computational complexity.
Solution Approach 2:
The patent performs channel estimation using sounding signals transmitted in advance before data communication begins. This preliminary channel characterization allows the receiver to prepare equalization parameters beforehand, reducing the computational burden during actual data transmission.
4Reliability
If LMMSE receiver is used with OTFS to enhance interference cancellation capabilities, then communication performance improves, but the computational complexity increases making it unsuitable for high-mobility edge communication applications
Solution Approach 1:
Instead of using the full LMMSE receiver which provides optimal but computationally intensive interference cancellation, the patent employs a simplified receiver design that uses channel sounding signals and pilot signals to achieve sufficient interference cancellation for the specific application scenario, balancing performance and complexity.
Solution Approach 2:
The patent uses inexpensive channel sounding signals and pilot signals that can be transmitted periodically to enable effective channel estimation and equalization. These auxiliary signals are computationally inexpensive to process and provide sufficient channel information without requiring complex real-time signal processing.
Data Source
AI summary
The disclosure relates to method and system for providing a MIMO transceiver in high speed mobility. The method includes dividing, by the wireless MIMO transmitter, transmission data into a plurality of transmit chains corresponding to an antenna. The method further includes generating for the plurality of transmit chains, a Circularly Pulse Shaped Orthogonal Time Frequency Space (CPS-OTFS) time frequency signal based on a first primary parameter. Value of the first primary parameter is determined based on a first predefined algorithm. The method further includes converting for the plurality of transmit chains, the CPS-OTFS time frequency signal to a CPS-OTFS time domain signal based on at least one of a plurality of secondary parameters. A first plurality of N-point Inverse Fast Fourier Transform (IFFT) are employed on the CPS-OTFS time frequency signal. The first plurality corresponds to the number of sub-carriers and N corresponds to a set of time symbols.