Characterizing TCP/IP for High Frequency Communication Systems

Abstract

TCP/IP over HF has largely been avoided due to high error rates and the low bandwidth available. With Wideband HF (WBHF) gaining traction around the world, TCP/IP over HF is being revisited and options are starting to be explored. Although WBHF provides more bandwidth over what was previously available, it does not overcome the error prone behavior of the HF channel which is governed by physics and environmental conditions. In this paper we examine the characteristics of TCP/IP when it operates in an HF environment. We derive the thresholds of key variables that impact TCP/IP communications and analyze the protocol with respect to other communication parameters. We then discuss the interdependencies of TCP parameters when applied to an HF environment. Based on these findings, we recommend a set of design principles for HF-TCP, a TCP stack for TCP over HF communications. Experimentation is conducted on a model built in OMNet +++ with its individual modules fine-tuned to provide the capability to simulate HF environmental factors.