Digital UWB Pulse Shaping for FCC Mask and NBI Avoidance
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Solution Overview
Problem
Ultra-wideband (UWB) communication systems face challenges in maximizing power and bandwidth within the FCC spectral mask while avoiding narrow-band interference (NBI) and carrier frequency offset/jitter, especially in multi-band systems, due to limitations in existing pulse shaping techniques.
Innovation Solution
The use of a digital filter in UWB transmitters to generate digitally filtered pulses that maximize power and bandwidth within the FCC spectral mask, reduce power in NBI frequency bands, and adapt to changes in interference and regulatory requirements, employing techniques such as the Parks-McClellan algorithm for filter design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional UWB transmitters utilize carrier modulation and baseband analog filtering, then the system can generate UWB pulses, but the power and bandwidth within the FCC spectral mask are not maximized and the system is susceptible to carrier frequency offset and jitter
Solution Approach 1:
The patent replaces the mechanical/analog carrier modulation system with a digital filtering system. Instead of using local oscillators and analog mixers that are prone to frequency offset and jitter, the invention uses digital signal processing to generate UWB pulses directly from baseband signals, eliminating the carrier frequency stability issues inherent in analog systems.
Solution Approach 2:
The patent changes the spectral parameters of the UWB signal by applying digital filters with specifically designed transfer functions. These filters are optimized to maximize power within the FCC spectral mask while maintaining pulse integrity, thereby improving both power efficiency and reliability without requiring carrier modulation.
2Area of stationary object
If UWB transmitters operate across the full UWB spectrum, then bandwidth is maximized, but narrow-band interference from WLAN and other services cannot be avoided
Solution Approach 1:
The patent applies local quality by designing digital filters with frequency-selective characteristics that allow different parts of the UWB spectrum to be treated differently. The filters are configured to pass desired UWB frequencies while attenuating specific narrow-band interference frequencies, thereby maintaining overall bandwidth utilization while protecting against harmful interference at specific frequency locations.
Solution Approach 2:
The patent converts the presence of narrow-band interference into a design constraint that benefits the system. By identifying WLAN and other NBI frequency bands, the invention designs digital filters that actively suppress these interference frequencies, transforming the harmful interference problem into an opportunity to demonstrate the superiority of digital filtering over analog approaches.
3Power
If digital filtering is implemented in UWB transmitters, then power and bandwidth within FCC spectral mask can be maximized and NBI avoided, but the device complexity increases compared to conventional analog filtering
Solution Approach 1:
The patent applies segmentation by dividing the digital filtering function into discrete, manageable components such as tap coefficient sets and filter stages. This modular approach allows the complex digital filtering task to be broken down into simpler operations that can be efficiently implemented in digital signal processors or FPGAs, reducing the practical complexity burden.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and storing optimal tap coefficient sets for different filtering requirements. Instead of performing complex real-time filter design, the system uses pre-computed coefficients that are loaded into the digital filter, significantly reducing the computational complexity and processing requirements during actual UWB signal generation.
4Adaptability or versatility
If the UWB spectrum is shared with WLAN and other services, then frequency band utilization is improved, but interference to and from these services occurs
Solution Approach 1:
The patent applies preliminary anti-action by proactively designing digital filters that suppress UWB signal components in WLAN and other protected frequency bands before transmission. This pre-emptive approach prevents interference from occurring in the first place, allowing UWB systems to share the spectrum with WLAN and other services without causing harmful effects, thereby improving overall frequency band utilization.
Data Source
AI summary
The invention provides an ultra-wideband (UWB) transmitter and various techniques for generating digitally filtered UWB pulses that substantially maximize power and bandwidth in one or more frequency bands while allowing narrow-band interference (NBI) to be avoided, e.g. interference to and from wireless local area networks (WLANs). In particular, the UWB transmitter utilizes a digital filter to generate digitally filtered UWB pulses to substantially maximize power and bandwidth in the Federal Communications Commission (FCC) spectral mask for UWB communications. In one embodiment, the invention provides a method comprising generating digitally filtered ultra-wide band (UWB) pulses to substantially maximize power in one or more frequency bands of a UWB spectrum and to substantially reduce power in one or more NBI frequency bands of the UWB spectrum. The invention may be implemented without modifying the analog components of existing UWB transmitters.