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Published on: March 20, 2017
Full duplex transmission operation of a 2.45-GHz asynchronous spread spectrum using a SAN convolver
K Tsubouchi1, H Nakase, A Namba
1Res. Inst. of Electr. Commun., Tohoku Univ., Sendai.
Summary
This study presents an asynchronous spread spectrum (SS) modem using a ZnO-SiO(2)-Si surface acoustic wave (SAW) convolver for efficient 2.45-GHz band communication. The developed modem demonstrates robust self-jamming rejection, achieving a 10(-6) bit error rate.
Area of Science:
- Electrical Engineering
- Materials Science
- Telecommunications
Background:
- Surface Acoustic Wave (SAW) devices offer unique signal processing capabilities.
- Spread Spectrum (SS) modulation enhances communication robustness against interference.
- Efficient modem design is crucial for wireless communication systems.
Purpose of the Study:
- To implement an asynchronous Spread Spectrum (SS) modem operating in the 2.45-GHz band.
- To utilize a Zinc Oxide–Silicon Dioxide–Silicon (ZnO-SiO(2)-Si) surface acoustic wave (SAW) convolver for modem functionality.
- To evaluate the modem's performance, particularly its self-jamming rejection capabilities.
Main Methods:
- Implementation of a full duplex asynchronous SS modem using Direct-Sequence/Code-Shift-Keying (DS/CSK) modulation.
- Employment of a ZnO-SiO(2)-Si SAW convolver for asynchronous demodulation.
- Utilizing pseudonoise (PN) codes from a preferred pair of m-sequences (period 127) at a 14 MHz code rate.
- Incorporation of an RF isolator and SS process gain to mitigate self-interference.
Main Results:
- Successful implementation of the asynchronous SS modem in the 2.45-GHz band.
- Demonstration of asynchronous demodulation leveraging the SAW convolver's correlation properties.
- Effective reduction of self-interference through RF isolator and SS process gain.
- Confirmation of adequate self-jamming rejection with a bit error rate (BER) of 10(-6) at a desired-to-undesired-signal ratio of -78.3 dB.
Conclusions:
- The ZnO-SiO(2)-Si SAW convolver is an efficient component for asynchronous SS modem implementation.
- The developed modem exhibits strong self-jamming rejection, suitable for robust wireless communication.
- The asynchronous demodulation approach using SAW convolvers is a viable technique for high-frequency band applications.
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