Generalised link-layer adaptation with higher-layer criteria for energy-constrained and energy-sufficient data terminals

It has long been recognised that a wireless communication system can be more efficient if link-layer parameters such as modulation order are adapted to the channel conditions. The most common optimising criterion is spectral efficiency (bps/Hertz) subject to very low bit-error constraint. But this criterion is not appropriate for practical communication networks fitted with strong data-packet error detection and a mechanism for selective packet re-transmission. In such scenario, packet-oriented criterion for link adaptation, such as the "goodput", seems more appropriate. Herein we follow recent literature in performing link adaptation under "goodput" oriented criterion. But we focus on axiomatic properties of the packet-success rate function (PSRF). The benefits are generality, robustness and technical accuracy. In particular, our analysis applies to arbitrary combinations of link-layer parameters, as long as the resulting PSRF is an S-curve. We obtain a robust result: a set of possible link configurations can be ranked by the slope of a tangent line from the origin to the graph of a scaled version of the PSRF. Some link configurations can dominate others under all scenarios. We consider separately energy-limited (e.g., battery-fed) and energy-sufficient (e.g., vehicular) terminals, and provide graphical illustration of our results.