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Papers by William Ivancic

NASA Earth Science …, 2008

In support of satellite-ATM interoperability, researchers at the NASA Lewis Research Center perfo... more In support of satellite-ATM interoperability, researchers at the NASA Lewis Research Center performed asynchronous transfer mode (ATM) quality-of-service experiments using MPEG-2 (ATM application layer 5, AAL5) over ATM over an emulated satellite link. The purpose of these experiments was to determine the free-space link quality necessary to use the ATM protocol to transmit high-quality multimedia information. The experimental results have been submitted to various International Telecommunications Union (ITU) study groups in order to improve and modify current standards and recommendations for the telecommunications industry. Quality-of-service parameters for Class I, stringent class requirements for ITU-T I.356 are currently being debated. The experimental results presented will help to establish these quality-of-service thresholds. This material will also be useful in the development of the ITU-R WP-4B's Draft Preliminary New Recommendation on the Transmission of Asynchronous ...

been developed as a reliable transport protocol to carry PSTN signaling messages over an IP netwo... more been developed as a reliable transport protocol to carry PSTN signaling messages over an IP network. Multistream-ing is one of its powerful features to overcome some of the bottlenecks of single streamed protocols such as TCP. In this paper, we study the impact of multistreaming on the performance of SCTP over error prone satellite networks. We show that multistreaming results in higher goodput and reduces the bu®er requirements at the wireless receiver. I.

IETF has proposed Mobile IPv6-based Network Mobility (NEMO) basic support protocol (BSP) to suppo... more IETF has proposed Mobile IPv6-based Network Mobility (NEMO) basic support protocol (BSP) to support net-work mobility. NEMO BSP inherits all the drawbacks of Mobile IPv6, such as inefcient routing path, single point of failure, high handover latency and packet loss, and high packet overhead. To address these drawbacks, we proposed an IP diversity-based network mobility management scheme called Seamless IP-diversity based NEtwork MObility (SINEMO). In this paper, we develop an analytical model to analyze and compare the signalling costs of SINEMO and and NEMO BSP. Our analysis shows that SINEMO reduces the signalling cost by a factor of two when compared to NEMO BSP. I.

Mobile IP, a IETF standard to handle mobility of Internet hosts has some existing problems like h... more Mobile IP, a IETF standard to handle mobility of Internet hosts has some existing problems like high handover latency, packet loss, inefficient routing etc. To overcome these problems, we designed alternative novel approach called S eamless I P diversity based Generalized Mobility Architecture ( SIGMA), which utilizes multihoming and uses a transport layer protocol, Stream Control Transmission Protocol (SCTP). In our previous work, we have achieved a low latency handoff when MN moves between adjacent wireless network. Our analysis of our system showed that Mobile Node (MN) in SIGMAsuffers some instability during handoff (i.e.,) MN makes use of multiple interface cards while in the overlapping region of the wireless network, which is due to the in-efficient handoff scheme of SIGMA. This instability can be eliminated by using a efficient handoff scheme, thus enhancing the stability of theSIGMA. So the objective of this paper is to design an efficient handoff scheme for SIGMA to overco...

2019 Integrated Communications, Navigation and Surveillance Conference (ICNS), 2019

The popular Internet Protocol (IPv4) has been used operationally in space on the Disaster Monitor... more The popular Internet Protocol (IPv4) has been used operationally in space on the Disaster Monitoring Constellation (DMC) satellites for remote sensing tasks since 2003. The UK-DMC satellite carries the Cisco router in Low Earth Orbit (CLEO) as an experimental payload, and use of IPv4 with CLEO and to command and control the UK-DMC satellite was demonstrated in 2004. As a commercial Internet router, CLEO is also capable of using the newer IPv6 protocol, and of securing communications using IPsec. We describe our experiences in using IPv6 and IPsec onboard this satellite, and as part of a larger merged space/ground infrastructure built around use of the Internet Protocol. This is the first time that IPsec and IPv6 have been operated onboard a satellite in orbit.

Telecommunication Systems

ABSTRACT

15th International Communicatons Satellite Systems Conference and Exhibit

14th International Communication Satellite Systems Conference and Exhibit

NASA-Lewis' Space Electronics Div. supports ongoing research in advanced satellite communicat... more NASA-Lewis' Space Electronics Div. supports ongoing research in advanced satellite communication architectures, onboard processing, and technology development. Recent studies indicate that meshed VSAT (very small aperture terminal) satellite communication networks using FDMA (frequency division multiple access) uplinks and TDMA (time division multiplexed) downlinks are required to meet future communication needs. One of the critical advancements in such a satellite communication

ABSTRACT Asynchronous transfer mode (ATM) quality of service (QoS) experiments were performed usi... more ABSTRACT Asynchronous transfer mode (ATM) quality of service (QoS) experiments were performed using MPEG-2 (ATM application layer 5, AAL5) over ATM over an emulated satellite link. The purpose of these experiments was to determine the free-space link quality necessary to transmit high-quality multimedia information by using the ATM protocol. The detailed test plan and test configuration are described herein as are the test results. MPEG-2 transport streams were baselined in an errored environment, followed by a series of tests using, MPEG-2 over ATM. Errors were created both digitally as well as in an IF link by using a satellite modem and commercial gaussian noise test set for two different MPEG-2 decoder implementations. The results show that ITU-T Recommendation 1.356 Class 1, stringent ATM applications will require better link quality than currently specified; in particular, cell loss ratios of better than 1.0 x 10(exp -8) and cell error ratios of better than 1.0 x 10(exp -7) are needed. These tests were conducted at the NASA Lewis Research Center in support of satellite-ATM interoperability research.

Nasa Sti Recon Technical Report N, Jul 1, 1988