General approach for the comparison of spectrum efficiency of digital mobile radio systems

Evaluation of spectrum efficiency in mobile radio systems is often performed by different authors starting from different working assumptions; that yields results that are not easily comparable outside the `scenario' where they have been achieved. This paper attempts to settle this controversial matter providing some criteria for overcoming these difficulties. The results of this investigation allow to assess that relative capacity comparisons are fairly independent of some quality parameters, such as specified outage probability, or propagation parameters, such as the standard deviation of lognormal shadowing, so that these parameters need not complicate the comparison of competing approaches. As a consequence, a very simple scenario, providing an adequate basis for deriving constant efficiency curves, turns out to be of great relevance for comparisons. Associated with it, a graphic tool, allowing to perform quick relative comparisons among systems, is presented.