Sub-terahertz Receiver Using Analog Projection and Joint Demodulation
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Solution Overview
Problem
Current technologies face challenges in demodulating wide frequency strips in the sub-terahertz spectrum due to limitations in digital analog converters and significant phase noise from high-frequency oscillators, particularly in mobile terminals with limited resources.
Innovation Solution
A method combining energy detection and projection of signals onto an analog Fourier base, followed by joint demodulation using a maximum likelihood algorithm, which reduces sampling frequency requirements and mitigates phase noise by using quadrature signals, allowing asynchronous operation and lower sampling frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If coherent architecture with multiple frequency channels is used to demodulate broadband signals, then the frequency band coverage is improved, but the phase noise sensitivity increases and device complexity increases
Solution Approach 1:
The broadband signal is divided into multiple frequency channels, each processed independently through its own demodulation path. This segmentation allows the receiver to handle wide frequency bands while keeping each individual processing chain simple and manageable, avoiding the need for a single complex demodulator.
Solution Approach 2:
A phase noise estimator acts as an intermediary component that measures phase noise from the local oscillator and provides compensation signals to multiple demodulation channels. This mediator approach allows phase noise correction to be distributed across all channels without increasing the complexity of each individual channel's core demodulation logic.
2Speed
If high-frequency oscillators are used for sub-terahertz signals, then the signal frequency coverage is improved, but phase noise increases
Solution Approach 1:
A phase noise estimator continuously monitors the phase noise generated by the high-frequency local oscillator and feeds back compensation information to the demodulation process. This feedback mechanism allows the system to maintain high-frequency operation while actively correcting phase noise degradation in real-time.
Solution Approach 2:
The patent replaces traditional coherent demodulation methods that are highly sensitive to phase noise with energy detection-based demodulation. This substitution reduces the system's sensitivity to phase noise, allowing high-frequency oscillators to be used without proportionally increasing phase noise impact on signal quality.
3Adaptability or versatility
If analog-to-digital converters operate at high sampling frequencies to digitize wide frequency bands, then the digitization capability is improved, but the converter complexity and resource consumption increase
Solution Approach 1:
The wide frequency band is divided into multiple narrower frequency channels, each of which can be digitized at a lower sampling frequency. This segmentation allows the use of simpler, lower-speed analog-to-digital converters while still achieving comprehensive coverage of the broad frequency band through parallel processing of multiple channels.
Data Source
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AI summary
Method of receiving a modulated signal comprising the steps of: - Receiving (201) a signal modulated by pulse position modulation (PPM) or pulse width modulation (PWM) or pulse amplitude modulation (PAM) or amplitude modulation of the "On-Off Keying" (OOK) type, corresponding to the transmission of a sequence of one or more consecutive digital symbols.- Perform squaring (202) of the received signal, - Project (203) the square of the received signal onto several components of an analog signal basis to obtain an analog vector of dimension equal to the number of projection components, the components of the analog signal basis being non-constant functions, - Digitize (204) the analog vector into a digital vector, Demodulate (205) jointly the components of the digital vector using a maximum likelihood algorithm to estimate the transmitted sequence of one or more consecutive digital symbols.