Energy‐efficiency region for multiple access channels

To investigate the trade‐off between energy efficiency (EE) and spectral efficiency (SE) for Gaussian multiple access channels (MACs), a novel concept of the EE region is developed. The EE region for the time division multiple access system is also derived and compared. The SE–EE trade‐off order is introduced to explicitly describe how fast the EE decays with SE in the high SE region. For a symmetric MAC, a constraint on SE–EE trade‐off orders is derived and the Pareto optimum can be achieved by the corner points on the EE region.