3GPP LTE-WLAN Aggregation Technologies: Functionalities and Performance Comparison

The use of license-exempt bands offers a promising opportunity to additionally enhance operator networks to meet the future traffic demand. The recent specification efforts in 3GPP have resulted in two major aggregation features that enable LTE networks to benefit from unlicensed spectrum via WLAN. In this article, we provide a thorough overview of these features known as, LTE-WLAN aggregation (LWA) and LTE-WLAN radio level integration with IP security tunnel (LWIP). The article presents and motivates the design choices of protocol architectures, procedures, mobility, and security. It also proposes flow control algorithms suitable for both technologies, which aim at the best usage of licensed and unlicensed spectrum. Simulation results show the performance unveiling the potential gains of these features in different load conditions, also in a comparative manner, showing that LWA substantially outperforms LWIP.