Power amplifier efficiency ceilings due to signal modulation type

Energy efficiency in communications of all types is of growing importance to society. All efficiency loss is due to power dissipation in the electronic circuitry used to implement the communication standard. Selection of the modulation adopted by a standards working group has a dominant role in how much of the energy efficiency available from electronic technologies and circuit structures can be made visible to the communications application. Prediction of whether a particular modulation in consideration will either allow implementers to realize high values of energy efficiency - or will force implementers to use circuit techniques which place a low ceiling on the achievable energy efficiency - is an important step that must be performed during modulation selection deliberations. Prediction of this efficiency cap, if any, is readily achieved by the calculation proposed in this mostly tutorial paper. An initial comparison of presently used signal modulations is provided.