Dynamic Spectrum Access provides a group of radios with the ability to adapt to a changing RF environment by coordinating simultaneous changes to known, good frequencies amongst all radios in the group. This paper describes an implementation of DSA on a previously fielded software defined radio supporting networks of up to 16 radios. A TDMA protocol operating at the application level was used for DSA control communications using the same waveform as the voice communications. The DSA application controlled switching between the voice waveform and an FM waveform used for radio spectrum sensing. All nodes in the network shared spectrum quality data implementing a distributed channel quality algorithm enabling cooperative as well as individual or “blind” switching to new frequencies as required to maintain optimal network voice communications. Frequency harvesting, the discovery of new frequencies for use in the network, was performed using a third party broadband receiver running channel quality analysis software.
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