Adaptive and Optimized Scheduling Mechanism for Heterogeneous Wireless Networks Using an Explicit Flag Based Reinjection Approach

The use of mobile devices with multiple interfaces has transformed communication by enabling simultaneous data transfers. This capability has driven the adoption of the Multipath Transmission Control Protocol (MPTCP), which leverages multiple interfaces to transmit data concurrently over different paths, improving overall connectivity. However, several factors affect MPTCP performance, including fluctuations in sub-flows, out-of-order (OOO) packet delivery, and inefficiencies in retransmitting lost packets. Addressing these challenges is crucial for enhancing MPTCP efficiency. Optimizing retransmission strategies can improve both throughput and reliability while mitigating sub-flow irregularities ensuring stable communication. Although various methodologies have been proposed, most existing approaches primarily focus on packet scheduling, with limited emphasis on lost packet retransmission as a distinct issue. This work highlights the importance of retransmission alongside scheduling mechanisms. The proposed approach consists of three key modules, identification of packets requiring retransmission, selection of the optimal path, and transmission of these packets through an active and available route. To achieve this, our methodology marks lost packets with a retransmission flag and efficiently routes them through the selected path, enhancing MPTCP and minimizing delays in data delivery. The proposed scheme was implemented in NS-3.4 and evaluated using delay-sensitive applications. The results demonstrate that our methodology significantly outperforms existing approaches, making it a promising solution for improving MPTCP performance. Specifically, FBMPTCP-CWND and FBMPTCP-SSTHRESH achieve superior performance over the existing methodology by increasing throughput by 5%, reducing jitter by 13%, lowering packet retransmissions by 33%, and decreasing delay by 8%.