Abstract: Recently, 5G systems started to explore the usage of mmWave bands both for access and backhaul due to the extremely large portion of bandwidth available. Cellular systems operating at such frequencies would achieve a significantly higher capacity than current systems. Due to the propagation characteristics at those frequency bands, highly directional links may frequently switch between Line-of-sight and outage if the beam is blocked by obstacles. Such intermittent connectivity combined with high throughput however causes TCP to perform very badly. In this paper, we study the performance of several TCP variants in intermittend mmWave links. We focus on latency aspects as 5G systems should be designed for very low latency. We use ns-3 in emulation mode (DCE) and experiment with real Linux TCP implementations. Unfortunately, all TCP variants that we evaluated, increase the latency tremendously when the mmWave link characteristics switch from Line-of-sight to non Line-of-sight. In addition, when applying bufferbloat solutions such as CoDel, the latency can be controlled at the expense of low throughput. Based on our findings, we develop a method which transparently tunes the receive window of the TCP connections both for upload and download to effectively maintain low latency while at the same time achieving high capacity.