Performance Evaluation of Carrier Aggregation as a Diversity Technique in mmWave Bands

Millimeter wave (mmWave) frequencies have been selected to provide the high data rates and capacity targeted by the next generation (5G) of mobile communication networks. Compared to the sub 6-GHz bands that have been historically exploited by popular communication systems, mmWave bands suffer from adverse radio propagation degradations such as higher path loss and blockage, however they provide significantly larger bandwidths and lower levels of usage than sub 6-GHz bands. Mobile operators can employ Carrier Aggregation (CA) techniques to combine the newly acquired spectrum in mmWave bands with their already allocated spectrum in sub 6-GHz bands. The use of CA as a technique to combine chunks of spectrum in a transparent manner for higher layers of the protocol stack has been widely researched. In this paper, a different focus is considered by exploring the use of CA as a diversity technique in order to further improve the network capacity under various radio propagation scenarios. The obtained results indicate that CA can effectively be exploited as a diversity technique to optimize the overall system performance and increase the network capacity, with the optimum number of component carriers depending on the radio propagation distance.