N01-052
TITLE: Compressed Internet Protocol (IP) Data Via Geosynchronous Earth Orbit (GEO)
Satellite Circuits
TECHNOLOGY AREAS: Information Systems
DOD ACQUISITION PROGRAM SUPPORTING THIS TOPIC: ACAT III: Submarine High Data Rate
OBJECTIVE: Investigate and define the characteristics of an optimal protocol for the reliable transmission
of digital data over a Geosynchronous Earth Orbit (GEO) satellite with limited data bandwidth; inconsistent
Bit Error Rate (BER) performance; intermittent operation; and a Local Area Network (LAN) interface on
each end of the communication link.
DESCRIPTION: One of the goals for the next generation of shipboard communication systems is
"transparent" network connectivity: Users wish to send or receive data in a manner that is independent from
the operation of the radio room or the utilization of specific communications circuits. Current plans for the
future submarine computer network systems include the usage of Transmission Control Protocol/Internet
Protocol (TCP/IP), Asynchronous Transfer Mode (ATM), and Local Area Network Emulation (LANE)
protocols.
The execution of these Commercial Off-The-Shelf (COTS) methodologies is beset with unique difficulties
in the submarine operational environment.
Satellite communications links are intermittent and short-term due to the stealth nature of submarine
operations: It is frequently desirable to minimize the length of time at which the submarine is at periscope
depth, which is currently essential for submarine satellite communication. Consequently, “transparent”
network connectivity requires a sophisticated system for queuing data and the execution of a complex array
of Quality of Service (QoS) parameters.
In many operational situations, a submarine is unwilling to transmit a radio signal unless it has a Low
Probability of Detection (LPI) characteristic; many times, complete radio silence is required. In these
situations, it is impossible for the submarine to return the packet reception acknowledgement data that is
required for COTS TCP/IP operation.
The data rate and Bit Error Rate (BER) of submarine-based satellite communications links is frequently
inferior to the typical performance of the same types of links in surface-ship applications. Consequently,
the optimal utilization of data compression and error correction techniques is essential in order to achieve
Fleet requirements for data rates and availability.
COTS TCP/IP and ATM protocols have not been designed to perform well within the above constraints.
Therefore, enhancements to these commercial protocols are essential for the optimal implementation of IP
and ATM protocols within submarine satellite communication systems.
PHASE I: Develop enhancements to COTS IP and ATM protocols; these may be “original” or
based upon published literature. With guidance from the user community, end-to-end simulation scenarios
will be developed and executed. The deliverable will be a report providing a detailed description of the
proposed protocols, simulations, results, and conclusions.
PHASE II: Implement the best approach (or approaches) into hardware and software that
represents a close approximation of actual submarine satellite communication systems. The performance of
the enhanced protocols will be tested under realistic SATCOM link conditions.
PHASE III: The successful protocol enhancements from Phase II will be integrated into actual
Navy-owned submarine communication system hardware. Field-testing will be performed to characterize
the performance of these protocols in comparison with those that are currently in use by the Fleet.
COMMERCIAL POTENTIAL: The protocols developed during this program may be useful in commercial
wireless applications that employ TCP/IP in a low data rate/relatively high BER environment. For
example: TCP/IP via mobile telephone.
REFERENCES:
1. R. Goyal, R. Jain et. al, “Simulation Experiments with Guaranteed Frame Rate for TCP/IP Traffic,”
ATM Forum 97-0607
2. R. Goyal, R. Jain et. al, “UBR+: Improving Performance of TCP over ATM-UBR Service,”
Proceedings ICC’97, June 1997.
3. Allyn Romanov, Sally Floyd, “Dynamics of TCP Traffic Over ATM Networks, “ IEEE Journal of
Selected Areas in Telecommunications, May 1995.
KEYWORDS: TCP/IP; ATM; satellite; protocols; QoS; enhanced