VISIBLE: Virtual Congestion Control with Boost ACKs for Packet Level Steering in LWIP Networks

Abstract

Tightly coupled LTE-Wi-Fi networks have emerged as a promising solution for improving capacity and coverage of wireless networks. Different architectures which realize this integration includes LTE-Wi-Fi radio level interworking with IPSec tunnel (LWIP) and LTE-Wi-Fi Aggregation (LWA). The major issue with these architectures is that they do not exhibit expected performance when TCP is employed, i.e., TCP throughput decreases compared to using either LTE or Wi-Fi for transmission. Also, Multipath TCP (MPTCP) is inefficient while aggregating LTE and Wi-Fi links, especially when the link rates are incomparable. In this paper, we propose VIrtual congeStion control wIth Boost acknowLdgEment (VISIBLE) algorithm for LWIP networks which encompasses an efficient packet level traffic steering technique for steering Downlink traffic across LTE and Wi-Fi links of LWIP node and Boost ACK technique to reduce the number of duplicate ACKs (DUP-ACKs) delivered to the TCP sender. Unlike MPTCP, VISIBLE+LWIP uses both LTE and Wi-Fi links efficiently even if their link rates are incomparable and reduces unnecessary DUP-ACKs. We have developed VISIBLE+LWIP framework in NS-3 and compared its performance with the state-of-the-art MPTCP algorithms. We could observe that the proposed VISIBLE algorithm has doubled the throughput of basic LWIP and outperformed throughput of MPTCP by 37%. Also, it has enhanced the throughput by 30% as compared to basic LWA.