Towards LTE-Advanced and LTE-A Pro Network Simulations: Implementing Carrier Aggregation in LTE Module of ns-3

Abstract

Carrier aggregation (CA) technology was introduced in 3GPP specification in Release 10, in 2011, as part of Long Term Evolution Advanced (LTE-A) standardization. Most of the operators recognized it as the most important technology in LTE-A since it allows to quickly turn investment in additional LTE carriers into higher data rates. This is because CA allows a quick adoption and an efficient usage of fragmented and non-contiguous spectrum. Additionally, CA is a key technology for enabling some of LTE-A Pro technologies which are proposed in Release 13 and 14, such as, aggregation with unlicensed frequencies in the downlink, known as licensed assisted access (LAA), and LAA with aggregation in the uplink, known as enhanced LAA (eLAA). In this paper we describe the CA extension of the LTE module of ns-3 network simulator that we have implemented and contributed to ns-3 community. Firstly, we describe the motivation and technology background. Then, we describe the extension from a technical perspective, highlighting the new application interface being introduced, and the modifications of prior ns-3 LTE model involving the control and data planes of both the user equipment (UE) and evolved node B (eNB) protocol stack. Finally, we provide description of example scenarios and the validation of the carrier aggregation feature providing a performance comparison of the LTE system with and without CA capability.