Toward the Implementation of MPTCP Over mmWave 5G and Beyond: Analysis, Challenges, and Solutions

5G and beyond 5G networks are going to be an inseparable part of human lives in the future. They will dominate any aspects of everyday activities from smart homes, remote surgery, and smart cities to autonomous driving, which demand high throughput through low latency end-to-end communication. Consequently, employing higher frequencies in millimeter-wave for the coming cellular networks will be inevitable. On the one hand, millimeter-wave can provide massive data rates; on the other hand, it suffers from some shortcomings such as blockage and misalignment that can occur because of the susceptible characteristic of the high frequencies. These flaws can mislead TCP in adjusting its sending rate efficiently and reduce the connection quality that a user discerns. Deploying Multipath TCP (MPTCP) is one of the schemes that can relieve the aforementioned issues and assist in utilizing the new generation mobile networks' high potential by leveraging its features in exploiting diverse paths in networks such as NR or LTE. A well-designed MPTCP can select the best path among the available ones, so it can enhance the perceived user experience. This paper fills the gap of having a comprehensive overview of MPTCP and its deployment over 5G and beyond 5G networks. It analyses millimeter-wave-based cellular networks, MPTCP procedures and parameters, state-of-the-art MPTCP congestion control mechanisms and schedulers, and the probable solutions that may enhance the protocol's functionality in cellular communication.