Energy efficient power allocation for carrier aggregation enabled communications systems

The Energy Efficiency (EE) of Carrier Aggregation (CA) enabled communications systems is studied. In more detail, the problem of the optimal power allocation for CA enabled systems exploiting multiple Parallel Frequency Bands (PFBs) is addressed based on an EE maximization criterion. Both the case of full Channel State Information at the Transmitter (CSIT) as well as the case of quantized CSIT are studied and novel EE-optimal power allocation algorithms are derived. The derived algorithms are used in order to investigate the relation between the system's EE and the system design parameters, e.g. The number of PFBs, the number of feedback bits and the fading conditions. Focusing on the problem of optimal feedback allocation, it is shown by means of simulations that the optimal allocation of feedback to the PFBs is related to the fading conditions. Moreover, focusing on the problem of the selection of the number of PFBs, it becomes evident that the optimal selection of the number of PFBs is strongly related to the number of available feedback bits. Thereby, the interplay between EE-optimal feedback and power allocation design and system parameters is explored. 2016 IEEE.Scopu