A dynamic spectrum access MAC appliqué for legacy military radios

There is interest in dynamically allocating spectrum due to the high degree of usage and interference in DoD wireless communications bands. While all bands may not always exhibit high usage, there are times and locations where radio usage is interrupted due to inability to access spectrum. With this in mind, the DoD has undertaken programs such as DARPA neXt Generation (XG) and Wireless Network After Next (WNAN) to develop methods for dynamic spectrum access (DSA). In DSA, a radio or set of radios may select to use a frequency channel at any given time on the basis of the sensed signal activity (or interference temperature) in that channel. Currently fielded military radios do not have such a DSA capability. The situation among DoD radios is such that there exist a variety of means of introducing DSA. Among these are: development of entirely new DoD radios, modification of the software load of current software-defined DoD radios to give them DSA capability, and finally the addition of a hardware and/or software applique to interface with existing DoD radios, particularly those not software-defined. Of course there will also be a class of DoD radios that are not suited for the addition of DSA capability. The DARPA WNAN Program is pursuing the first method above, by developing a new radio. The second method above is being pursued in the DARPA XG Program by modifying radio software to add DSA protocols and sensing. In this paper we consider a military radio set (the AN/PRC-117F and the like) which has the necessary features to allow a hardware/software sensing applique to be integrated with it resulting in a radio/sensor suite with cognitive features. This paper describes the design and implementation of such an applique, along with controlling software and its integration with the PRC-117F in a prototype fashion. The applique has been developed and tested in a laboratory environment.