Effects of Platform EMI in Synchronized Cooperative Broadcast Systems

On military platforms, several communication systems are colocated with electronic systems. The resulting electromagnetic environment can degrade communication performance. This is particularly evident in vehicles and other small platforms, where a lot of equipment is installed in a small space. A consequence of high electromagnetic interference (EMI) levels is a reduced communication range for radio systems. The focus of this article is to analyze how a complex interference situation affects frequency-hopping ad hoc networks using synchronized cooperative broadcast (SCB). SCB is a communication technique used by modern tactical wideband radios and a form of cooperative relaying. The interference environment, both background environment and platform interference, is viewed in terms of an increasing equivalent noise figure of the radio receiver. Additionally, there is interference from colocated radio systems yielding internetwork interference. The impact on SCB network performance from these interference sources is analyzed. The results show that SCB is robust toward interference in terms of a maintained high delivery ratio. However, in situations with low network diversity, EMI problems on some platforms can affect the whole network performance.