Green distributed antenna systems: Optimized design and upper bound for energy efficiency

Energy efficiency in Distributed Antenna Systems (DAS) has been an overlooked subject in favor of achieving the required coverage. In this paper, we demonstrate that DAS energy efficiency can be improved (in Joule/bit) up to an order of magnitude with retained Quality of Service. We also demonstrate that for an optical-wireless system there can be an optimum number of antennas which maximizes the energy efficiency.