Mixed-Mode Transceiver Blocker Resilience
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Solution Overview
Problem
Cognitive radio systems face challenges in co-existing with licensed and unlicensed users due to interference from blockers and jammers, and existing spectrum sharing proposals like the 11-band MB-OFDM for UWB communications have high power consumption, limiting their effectiveness.
Innovation Solution
A dual-mode transceiver system that employs a mixed-mode spread-spectrum technique, combining digital and analog domain spreading to increase tolerance to blockers and user collisions, using a pseudo-random sequence to spread the signal in both frequency and time domains, and a multi-level linearly interpolated pseudo-random sequence to reduce bandwidth requirements and improve interference rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spread spectrum techniques are used in cognitive radio systems, then interference tolerance is improved, but power consumption increases significantly
Solution Approach 1:
The patent segments the spread spectrum implementation into two distinct domains: analog domain spreading for robustness against blockers and jammers, and digital domain processing for efficient signal correlation and detection. This segmentation allows each domain to be optimized independently, achieving high interference tolerance through analog spreading while maintaining low power consumption through efficient digital correlation processing.
2Productivity
If spectrum sharing is implemented to accommodate multiple users, then spectrum utilization is improved, but user collision and interference increase
Solution Approach 1:
The patent introduces mixed-mode spread spectrum as an intermediary mechanism that enables multiple users to share the same spectrum without direct collision. By spreading signals in both analog and digital domains with unique pseudo-random codes, the system creates orthogonal signal spaces for different users, allowing simultaneous access to the same frequency resources while maintaining signal distinguishability and reducing inter-user interference.
3Adaptability or versatility
If broadband transceivers operate in underutilized federal spectrum bands, then spectrum availability is improved, but resilience to federal radar blockers decreases
Solution Approach 1:
The patent transitions from narrowband operation to broadband spread spectrum operation across multiple frequency dimensions. By spreading the signal energy across a wide bandwidth in the analog domain and using code division multiplexing in the digital domain, the system can operate in underutilized federal spectrum bands while the wide bandwidth provides inherent resilience to narrowband radar blockers through spectral diversity and processing gain.
Data Source
AI summary
Systems, devices, and methods are provided for mixed-mode signal processing that achieves unprecedented levels of out-of-band and in-band interference suppression. Embodiments of the present disclosure mitigate the effects of blockers and jammers, which have surfaced as issues in emerging cognitive radio systems as those networks struggle to co-exist with licensed and unlicensed users.