International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The growing need to transmit larger telemetry streams from the receiving site to the processor location over greater distances is requiring newer and more creative techniques. This paper reports efforts to use Asynchronous Transfer Mode (ATM) technology and inverse multiplexing to provide an economical system to interface telemetry streams into the public network for reliable transmission. Cost savings are available immediately for programs that are willing to meet the synchronization criteria today. Lab testing has shown the feasibility of using cost efficient techniques for data transmission. This document describes the investigation that is currently underway that could provide a significant change to the way telemetry data is transmitted from receiver sites to data processing sites. Instead of using dedicated lines with dedicated bandwidth regardless of the program being supported, the approach that has been tested in a lab environment would allow the dynamic allocation of bandwidth using ATM over a variety of carrier services. The combination of ATM and inverse multiplexing allows telemetry data rates above 1.5 Megabits per second (Mbps) to be transmitted over multiple T1 (1.544 Mbps) lines. Previously, the only choice when data rates exceeded 1.5 Mbps was to use an entire DS-3 (45 Mbps). Now it is possible to transmit intermediate sized data rates (1.5 to 8 Mbps) by bonding multiple T1s to provide the desired data throughput.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Asynchronous Transfer Mode (ATM) is a technology that is experiencing tremendous growth in the commercial telecommunications sector. Leveraging commercial investment and introducing ATM into today’s flight test range, while ensuring that all requirements are satisfied, are paying large dividends in capability and efficiency. The flight test community imposes unique requirements specifically with regards to telemetry that are not the norm of the commercial telecommunications industry. Efforts are underway at the Air Force Flight Test Center (AFFTC), Edwards Air Force Base (AFB) to implement an ATM system for all range communications. This paper addresses the unique requirements imposed by the flight test community, a revolutionary breakthrough from a commercial ATM vendor, and other challenges experienced while implementing this system. The system being implemented at Edwards will carry all types of range data over SONET/ATM hybrid equipment and interface to other flight test ranges and facilities over a mix of commercial leased lines and dedicated microwaves.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / As the number of telemetry applications at sites increases, the need for a higher bandwidth link from site-to-site grows. The use of an inverse T1 multiplexer allows the site to utilize multiple T1 lines rather than more costly higher bandwidth lines. There are many advantages to using a recognized packet standard, such as IRIG-107/98, over simply routing the streams through T1 lines. One advantage is that there is a total separation of data stream clock from T1 transmission clock, reducing synchronization circuitry and overhead. Another advantage is that the use of packets also allows for a smooth reconstructed clock phase on the receiving site, creating a virtually seamless transmission of clock and data. And, finally, by using a recognized packet standard, the inverse T1 multiplexer may easily be integrated into ranging and telemetry systems already incorporating packetized telemetry. This paper will discuss the combination of packets and inverse multiplexing to achieve an expandable transmission system capable of delivering a high bandwidth data stream across multiple T1 lines.

Computing devices are commonly equipped with multiple transport technologies such as IrDA, Bluetooth and WiFi. Transport switching technologies, such as Quality of Transport (QoT), take advantage of this heterogeneity to keep network sessions active as users move in and out of range of various transports or as the networking environment changes. During an active session, the goal is to keep the device connected over the best transport currently available. To accomplish that, this thesis introduces a two-phase decision making protocol. In phase one, intra-device prioritization, users indicate the relative importance of criteria such as speed, power, service charge, or signal range through a comprehensive user interface. QoT-enabled devices process this information with the prioritized soft constraint satisfaction (PSCS) scoring function to ascertain the transport that best meets the user's needs. The second phase, inter-device negotiation, facilitates two QoT-enabled devices in agreeing to a unified selection of the best transport. This phase uses a modified version of the PSCS scoring function based on the preferences of both users. Additionally, devices may utilize multiple transports simultaneously to more accurately meet user demands. The PSCS scoring function considers pairs of transports and calculates the ratio that will yield the desired performance. Another set of functions, also presented in this thesis, is then used to accomplish the desired performance level despite the potential introduction of additional overhead.