A study of TCP performance for mobile SATCOM system over blocking conditions

High throughput while minimizing packet latency are the essential requirements for deploying IP data over a SATCOM channel. To gauge the performance of IP data applications over a SATCOM channel, the performance of TCP/IP is often observed. This paper analyzes the TCP/IP throughput and delay performance characteristics as well as investigates the benefits gained by tuning TCP/IP parameters to mitigate its performance degradation due to delays and blockages inherent to a SATCOM channel. A hardware test bed is used to analyze the TCP/IP behavior under realistic satellite channel conditions. Experimental results are validated using OPNET simulation software. The comparisons show a perfect match between experimental and simulated results. Analysis shows that with the tuning of TCP/IP stack, it is capable of overcoming the effect of satellite channel delay while providing reliable delivery even through frequent blockage events. It is also shown that with a simple link layer retransmission process in place, the performance of TCP/IP can be further improved.