  Achieving a tighter level of aggregation between LTE and Wi-Fi networks at
the radio access network (a.k.a. LTE-Wi-Fi Aggregation or LWA) has become one
of the most prominent solutions in the era of 5G to boost network capacity and
improve end user's quality of experience. LWA offers flexible resource
scheduling decisions for steering user traffic via LTE and Wi-Fi links. In this
work, we propose a Collocated LTE/WLAN Radio Level Integration architecture at
IP layer (C-LWIP), an enhancement over 3GPP non-collocated LWIP architecture.
We have evaluated C-LWIP performance in various link aggregation strategies
(LASs). A C-LWIP node (i.e., the node having collocated, aggregated LTE eNodeB
and Wi-Fi access point functionalities) is implemented in NS-3 which introduces
a traffic steering layer (i.e., Link Aggregation Layer) for efficient
integration of LTE and Wi-Fi. Using extensive simulations, we verified the
correctness of C-LWIP module in NS-3 and evaluated the aggregation benefits
over standalone LTE and Wi-Fi networks with respect to varying number of users
and traffic types. We found that split bearer performs equivalently to switched
bearer for UDP flows and switched bearer outperforms split bearer in the case
of TCP flows. Also, we have enumerated the potential challenges to be addressed
for unleashing C-LWIP capabilities. Our findings also include WoD-Link
Aggregation Strategy which is shown to improve system throughput by 50% as
compared to Naive-LAS in a densely populated indoor stadium environment.
