On Digital Radio Receiver Performance in Electromagnetic Interference Environments

adiated emission from electronic equipment, co-located to a digital radio receiver, can affect receiving performance. It is therefore of great importance that this undesired emission be considered in the early design phase of a system containing radio equipment. For this purpose, methods to estimate the performance degradation on digital radio receivers in such environment must be available. From a military point of view, such methods are necessary for at least two important situations; 1) The communication system is not subject to interference from hostile jammers. In this case, undesired electromagnetic interference will decrease the operating range of the radio link. 2) The communication system is subject to interference from hostile jammers. In this case, the ability to withstand jamming is degraded by the undesired interference, as the latter degrades the signal protection devices in the communication system. A tactical consequence of this is that the jammer can obtain the same result at a larger distance than if no inherent interference is present. In this thesis, a method of performing this kind of performance analysis is proposed when the interference from co-located equipment is expressed in parameters from international standards concerning maximum allowed radiated interference limits. As existing standards were developed with respect to analog radio receivers, a method of relating these standards to digital radio receivers is needed. A method to relate an interference level to the bit error probability of a digital radio receiver exposed to that interference is proposed and evaluated. It is shown that the method proposed gives an estimated bit error probability that is close enough to the true value to be used in system design applications. The method is shown to give satisfactory results for both the non-jamming and the jamming cases With this method it is possible to compare the impact of different standard emission limits and, for instance, make a trade-off between economics and the tactical demands on a complex system. _______________________________________________________________________________________ 2 _______________________________________________________________________________________ 3