Cooperation in 4G - Hype or Ripe?

With increasingly congested frequency bands and an ever-growing demand for higher data rates, innovative approaches are needed to increase the spectral efficiency and hence cost per bit/s/Hz overless links. Cooperative systems and radios, which are capable of intelligently forming mutually cooperative entities, are a promising way to achieve this increase in capacity. First technological and then social barriers, however, have prevented us so far from having technologies, systems, or users jointly cooperate. We will try to answer in this article whether the time is ripe for a technology which has recently received so much hype.