Energy Efficiency in LTE-Advanced Networks with Relay Nodes

This document analyses the energy efficiency of two relaying schemes that represent a possible way to deploy a relay enhanced network: the two hop scheme and the multicast cooperative scheme. Results exist in literature that provide a model for the theoretical evaluation of the capacity improvement that these solutions can yield, however no analysis is available at present on the energy efficiency of these schemes. This work enhances the existing theoretical models for capacity evaluations, providing a first analysis from an energy efficiency point of view of these two approaches, considering a fully loaded network and the total emitted RF power of the transmitting nodes. Results are provided in terms of the Energy Consumption Index (ECI) of these schemes, a metric proposed in the EARTH project for the assessment of the energy consumption of network solutions. The ECI distribution is obtained and compared with the case of a network deployed without relay nodes, showing that besides the possible improvements in capacity, relays are also candidates as a valuable tool to reduce the energy consumption of a telecommunication network.