DPSK Receiver Dual-Path Adaptation for Transmitter Imperfections
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Solution Overview
Problem
Existing DPSK receivers face performance limitations when receiving signals from both 'dirty' and 'clean' transmitters, particularly in Bluetooth Enhanced Data Rate modes, due to fixed parameter settings, leading to suboptimal error rates and increased complexity.
Innovation Solution
A DPSK receiver with a dual-path architecture that dynamically selects between 'dirty' and 'clean' transmitter receive paths based on phase error estimates, using wide and narrow frequency offset estimation lowpass filters and demodulation reference filters, to adapt to transmitter imperfections and reduce error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a receiver is optimized for a 'dirty' transmitter with fixed parameter settings, then it can receive packets from dirty transmitters, but the error rate increases when receiving from clean transmitters
Solution Approach 1:
The receiver dynamically switches between two sets of parameter settings (dirty and clean) based on real-time detection of transmitter characteristics. The system monitors phase error estimates and automatically selects the appropriate receive path, transforming a static fixed-parameter receiver into a dynamic adaptive one that can optimize performance for different transmitter types without manual intervention.
Solution Approach 2:
The invention changes key receiver parameters including frequency offset estimation bandwidth, filter coefficients, and demodulation reference settings based on the detected transmitter type. By modifying these parameters dynamically, the receiver adapts its behavior to match the characteristics of the incoming signal, reducing errors for both dirty and clean transmitters.
2Reliability
If a receiver uses wide frequency offset estimation lowpass filter for dirty transmitters, then it can track frequency variations, but it increases complexity and reduces performance for clean transmitters
Solution Approach 1:
The receiver is segmented into multiple parallel processing paths: a first receive path with wide-frequency-offset estimation for dirty transmitters and a second receive path with narrow-frequency-offset-estimation for clean transmitters. Each path has its own dedicated filters and processing elements, allowing both modes to operate simultaneously without interference, thereby reducing overall system complexity compared to a single adaptive path.
Solution Approach 2:
The system dynamically selects which receive path to activate based on real-time detection of transmitter characteristics. By monitoring phase error estimates and comparing them against thresholds, the receiver automatically switches between wide and narrow filter configurations, optimizing frequency tracking performance for the current transmission conditions without maintaining both paths active at all times.
3Device complexity
If a receiver uses fixed parameter settings to simplify design, then device complexity is reduced, but it cannot adapt to different transmitter qualities
Solution Approach 1:
The receiver architecture is segmented into distinct first and second receive paths with specialized parameters for dirty and clean transmitters respectively. Each path includes its own frequency offset estimation unit, filter set, and demodulation reference generator. This segmentation allows the system to maintain simple, dedicated paths for each transmitter type while adding adaptability through the switching mechanism that selects the appropriate path based on detected transmitter characteristics.
Data Source
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AI summary
The invention discloses a DPSK-receiver for adapting to the imperfection of a transmitter consisting in an undesired time-dependent variation of the carrier frequency. The objective to present an apparatus and a method for adapting a receiver to the imperfection of a transmitter will be solved therein that a frequency offset estimation unit comprises a first and a second phase estimation unit and a dirty-clean-selector, whereas the first phase estimation unit, outputting a first phase error estimate edirty(k), comprises a first frequency offset estimation lowpass filter having a wider filter bandwidth than a second frequency offset estimation lowpass filter of the second phase estimation unit, outputting a second phase error estimate eclean(k), and the dirty-clean-selector is configured to compare a ratio of the second and first phase error estimates against a threshold value T and outputting a binary comparison result c(k), and the demodulation reference estimation unit comprises a first and a second filter, whereas the first filter as part of a "dirty"- receive-path of the receiver has a wider filter bandwidth than the second filter as part of a "clean"-receive-path of the receiver, whereas if the ratio of the second and first phase error estimates falls below the threshold value T the "clean"-receive path is used for outputting received information bits otherwise the "dirty"-receive path is used.