License-free communication using digital mobile radio standards and spread spectrum




McQuay, Colter James Alexander

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The concept of using spread spectrum and open radio standards to provide license-free, short range Peer-to-Peer (P2P) communication is explored. This research makes use of the Time Compression Overlap Add (TC-OLA) algorithm to transparently spread the spectrum of the Digital Mobile Radio (DMR) standard; this allows for reuse of existing hardware, software, and expertise relating to this well established protocol. Initial high level hardware designs of a communication device established the need to implement a proof of concept system which could be validated against Radio Frequency (RF) regulations. This proof of concept system was constructed using a hardware implementation of DMR processed through custom TC-OLA blocks in GNU Radio (GR). A spectral and performance analysis of this system was performed, showing that this approach has several benefits over existing license free communication options.



DMR, dPMR, TCOLA, Spread Spectrum, LMR, Mobile Radio, ISM, Radio Communications