Time Segment Based SDR Using PTSSBD Decimation
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Solution Overview
Problem
Current Software Defined Radio (SDR) systems lack full flexibility and efficiency due to complex IF stages, image frequency artifacts, and mismatches in I/Q channels, making it difficult to achieve competitive performance across various modulation techniques and wireless standards without customizing analog front-end and back-end blocks for each bandwidth and modulation scheme.
Innovation Solution
The implementation of Periodic Time Segment Sequence Based Decimation (PTSSBD) as a discrete time decimation filter, which enables a fully flexible and reconfigurable narrow band response, allowing the system to operate effectively across any band using broadband techniques, and includes a Time Segment Based Software Defined Radio (TSB-SDR) system that processes signals using time segment correlation and integration to achieve high signal-to-noise ratios and minimize mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IF stages are used in SDR systems, then frequency selection and signal processing are enabled, but spurs and image frequency artifacts are generated, creating complex usability limitations
Solution Approach 1:
The patent extracts the frequency selection function from traditional IF stages and relocates it to the digital domain through a reconfigurable filter bank. The filter bank selectively passes desired frequency components while digitally rejecting image frequencies and spurs, eliminating the harmful artifacts generated by analog IF mixing stages.
Solution Approach 2:
The patent replaces the mechanical/analog IF stage system with a digital signal processing system. The reconfigurable filter bank uses digital filtering techniques to achieve frequency selection, substituting the physical IF mixing process with computational methods that avoid generating spurs and image artifacts.
2Reliability
If customized analog front-end and back-end blocks are implemented for each bandwidth and modulation scheme, then competitive performance is achieved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent implements a universal reconfigurable filter bank that can be programmed to handle multiple bandwidths and modulation schemes through software control. The same physical hardware structure adapts to different wireless standards and signal characteristics by changing filter coefficients and configuration parameters, eliminating the need for customized analog blocks for each standard.
Solution Approach 2:
The patent introduces dynamic reconfigurability to the filter bank, allowing it to adapt its characteristics in real-time based on the required bandwidth and modulation scheme. The filter bank can be dynamically programmed through software to optimize performance for different wireless standards without requiring physical reconfiguration or customization.
3Adaptability or versatility
If quadrature modulation with phase variation is used, then various wireless standards are supported, but I/Q channel mismatches and orthogonality maintenance become ongoing challenges
Solution Approach 1:
The patent implements feedback mechanisms in the digital signal processing chain to detect and correct I/Q channel mismatches. The system continuously monitors orthogonality conditions and applies compensation algorithms to maintain proper I/Q balance, ensuring accurate quadrature modulation and demodulation across different wireless standards.
Solution Approach 2:
The patent uses digital signal processing to dynamically adjust I/Q channel parameters and compensate for mismatches. By changing processing parameters and applying correction algorithms in the digital domain, the system maintains orthogonality without being constrained by analog hardware imperfections.
4Device complexity
If conventional zero IF approaches are used to simplify IF complexities, then circuit complexity is reduced, but I/Q mismatch and orthogonality issues are compounded and noise performance degrades
Solution Approach 1:
The patent introduces a reconfigurable filter bank as an intermediary stage between the LNA and subsequent processing. This filter bank provides frequency selection and signal conditioning before the signal reaches the zero IF stage, enabling the system to maintain simplicity while improving noise performance by pre-filtering out-of-band interference and optimizing the signal spectrum before digitization.
Data Source
AI summary
A modulated signal is demodulated to obtain a modulation signal. The modulated signal is contained within an input signal. A periodic time segment sequence is defined having a plurality of ordered time segments. Signal values are acquired, from the input signal, during each ordered time segment. Signal values acquired during each ordered time segment are combined with signal values acquired during the same ordered time segment over multiple periods of the periodic time segment sequence. A local clock is generating. The modulated signal is demodulated by weighting the combined signal values by the local clock to obtain the modulation signal. the modulation signal is low-pass filtered to obtain a control signal. The generation of the local clock is controlled with the control signal.