PTSSBD Filtering for SDR Signal Acquisition
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Solution Overview
Problem
Current Software Defined Radio (SDR) technologies lack flexibility and efficiency in switching between different modulation techniques and wireless standards, due to complex IF stages and I/Q mismatch issues, leading to suboptimal performance and high costs.
Innovation Solution
The implementation of Periodic Time Segment Sequence Based Decimation (PTSSBD) filtering technique, which enables a fully flexible and reconfigurable narrow band response using broadband techniques, allowing for effective signal processing across any band and modulation scheme through Time Segment Based Software Defined Radio (TSB-SDR) systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional IF stages are used in SDR systems, then signal processing capability is improved, but device complexity and I/Q mismatch issues increase
Solution Approach 1:
The patent extracts the I/Q mixing and filtering functions from the traditional IF stage and relocates them to the baseband digital domain. The analog front end is simplified to only perform RF-to-DC conversion and basic filtering, while all complex signal processing operations are performed digitally, eliminating the complexity of analog IF stages and their associated I/Q mismatch problems.
Solution Approach 2:
The patent replaces the mechanical/analog IF stage with a digital signal processing system. The analog mixing and filtering operations are substituted with digital correlation and decimation operations, eliminating the need for precise analog component matching and reducing sensitivity to manufacturing variations.
2Reliability
If customized analog front-end receiver blocks are implemented for each wireless standard, then reception performance is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent implements a universal baseband processing architecture that can handle multiple wireless standards and modulation schemes through software configuration. The same hardware platform performs correlation, filtering, and demodulation for different standards by loading appropriate digital signal processing algorithms, eliminating the need for multiple customized analog front-ends and reducing manufacturing costs.
3Adaptability or versatility
If quadrature modulation with phase variation is used, then communication capability is improved, but I/Q mismatch and orthogonality maintenance complexity increase
Solution Approach 1:
The patent replaces analog I/Q mixing operations with digital correlation operations. Instead of using analog quadrature mixers that require precise 90-degree phase matching, the system uses digital reference signals correlated with the received signal in the baseband domain, eliminating I/Q mismatch and orthogonality maintenance issues while preserving full quadrature modulation capability.
4Device complexity
If zero IF approach is implemented, then I/Q mismatch issues are reduced, but noise performance degrades
Solution Approach 1:
The patent segments the signal processing into distinct stages: RF-to-DC conversion, digital correlation with time-segmented reference signals, and baseband reconstruction. This segmentation allows the system to process the signal in manageable portions, applying appropriate filtering and correlation operations at each stage to maintain noise performance while avoiding I/Q mismatch problems.
Data Source
AI summary
Values representative of modulation signal components are extracted from a modulated signal. The modulated signal contains a modulation signal. A periodic time segment sequence is defined having at least four ordered time segments. Multiple sets of signal values are acquired from the modulated signal. For each signal value, a difference in the modulated signal during each of two of the ordered time segments is acquired, as the signal value. The two ordered time segments differ in their order within the sequence by half of the number of ordered time segments in the sequence. Each set is acquired over multiple repetitions of the periodic time segment sequence. Each set is acquired during different ordered time segments than each other set. Each signal value is representative of a modulation signal component.