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 has resulted in two major aggregation features that enable Long Term Evolution (LTE) networks to benefit of unlicensed spectrum via Wireless Local Area Network (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.