OUTAGE PROBABILITY ANALYSIS FOR CELLULAR MOBILE RADIO SYSTEMS SUBJECTTO NAKAGAMI FADING AND SHADOWING

Empirical studies confirm that the received radio signals in certain c ellular systems are well modelled by Nakagami statistics. Therefore, p erforming relevant systems studies can be potentially useful to a syst em designer. A very useful statistical measure for characterizing the performance of a mobile radio system is the probability of outage, whi ch describes the fraction of time that the signal-to-interference rati o (SIR) drops below some threshold. A more refined criterion for the o utage is the Failure to simultaneously obtain a sufficient SIR and a m inimum power level for the desired signal. Thus, we derive new express ions for the probability of outage where a mobile unit receives a Naka gami desired signal and multiple, independent, cochannel Nakagami inte rferers. A salient feature of our results is that, unlike some previou s studies, the outage expressions do not restrict the Nakagami fading parameter m, to strictly integer values. Furthermore, since the receiv ed signals in mobile radio also experience log-normal shadowing, we an alyze the case where the received signals are modelled by a composite of Nakagami and log-normal distributions. Outage probabilities are com puted and graphically presented for several cases. The effect of speci fying a minimum signal requirement for adequate reception is found to introduce a floor on the outage probability. It is also found that sha dowing in macrocellular systems severely degrades the desired quality of service by increasing the reuse distance necessary for a given outa ge level.