William D. Ivancic

Handover schemes in satellite networks: state-of-the-art and future research directions

Low Earth Orbit (LEO) satellites will work as an important component in future data communication networks. LEO satellites provide low end-toend delays and efficient frequency spectrum utilization, making them suitable for personal communication. However, due to high satellite speed, ongoing communication using LEO constellations experiences frequent handover. In this article we provide an up-to-date, comprehensive literature survey on proposed handover schemes for LEO satellite systems. We also present a detailed classification of handover schemes based on a common framework. We first classify the schemes into link-layer and network-layer handover schemes. Link-layer handover schemes are further classified into three categories: spotbeam handover schemes, satellite handover schemes, and ISL handover schemes. Spotbeam handover schemes are categorized based on channel capacity, handover guarantee, and handover prioritization techniques. Network-layer handover schemes are also classified depending on connection transfer strategies. Finally, we compare the handover schemes using different quality of service (QoS) criteria.

Route optimization in network mobility: Solutions, classification, comparison, and future research directions

Network mobility (NEMO) handles mobility of a set of mobile nodes in an aggregate way using one or more mobile routers. NEMO introduces several advantages, such as reduced signaling, increased manageability, reduced power consumption and conservation of bandwidth when compared to individual host mobility. NEMO Basic Support Protocol (BSP), the IETF standard for NEMO, suffers from a number of limitations, like inefficient route and increased handoff latency. Most of the recent research efforts on NEMO have concentrated on solving the problem of inefficient route resulting in several route optimization schemes to solve the problem. To choose a route optimization scheme, it is very important to have a quantitative comparison of the available route optimization schemes. The objective of this article is to survey, classify and compare the route optimization schemes proposed in the literature over the last five years. We classify the schemes based on the basic approach for route optimization, and compare the schemes based on protocol overhead, such as header overhead, amount of signalling, and memory requirements. We conclude that performance of the classes of schemes has to be evaluated under criteria such as available bandwidth, topology of the mobile network and mobility type.

Effect of delay spike on SCTP, TCP Reno, and Eifel in a wireless mobile environment

Eifel has been proposed as a solution to enhance the performance of TCP during delay spikes in a wireless mobile environment. This paper evaluates and compares the performance of SCTP, TCP, and Eifel during delay spikes. We have shown that although Eifel performs better than TCP Reno and SCTP when there are no packet losses, the opposite is true when packets are lost in the presence of delay spikes. Our results also show that a higher link bandwidth does not always increase the data throughput of SCTP, TCP Reno, and Eifel.

Signalling cost analysis of SINEMO: seamless end-to-end network mobility

IETF has proposed Mobile IPv6-based Network Mobility (NEMO) basic support protocol (BSP) to support network mobility. NEMO BSP inherits all the drawbacks of Mobile IPv6, such as inefficient 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.

SINEMO: an IP-diversity based approach for network mobility in space

IETF proposed network mobility (NEMO) basic support protocol (BSP) to support network mobility. NEMO BSP is an extension of Mobile IP v6 (MIPv6), and inherits all the drawbacks of MIPv6 (like inefficient routing, high handover latency and packet loss rate). Satellites equipped with several IP-enabled devices are an example of network mobility in space networks. In this paper, we propose an IP-diversity based network mobility architecture called SINEMO, and show that SINEMO can exhibit better performance than NEMO BSP in satellite IP networks

SCTP over satellite networks

The stream control transmission protocol (SCTP) has recently been standardized as a new transport layer protocol in the IP suite. In addition to the core features of TCP, SCTP incorporates a number of advanced and unique features which are not available in TCP. The paper investigates the suitability of SCTP for data communications over satellite links. We describe SCTP features that allow SCTP to utilize the bandwidth of satellite networks better, while at the same time avoiding congestion collapse in a shared network. Finally, we provide recommendations on the use of SCTP over satellite networks.

Using Internet nodes and routers onboard satellites

An Internet router was integrated into the UK-DMC remote-sensing satellite as a secondary experimental payload. This commercial product has been orbiting in space for over three years. We describe the integration of the router and satellite and the successful on-orbit testing of the router, which took place using the Virtual Mission Operations Center (VMOC) application as part of a larger systems internetworking exercise. Placing this Cisco router in Low Earth Orbit (CLEO) onboard a small satellite is one step towards extending the terrestrial networking model to the near-Earth space environment as part of a merged space-ground architecture.

Evaluation of SCTP multistreaming over wireless/satellite links

In this paper, we study the impact of multistreaming on the performance of SCTP over satellite networks. We first show that multistreaming results in higher goodput than single streams when the receiver buffer is constrained as in the case of wireless handheld devices. We then demonstrate that the multistreaming feature of SCTP results in reduced buffer requirements at the receiver in the presence of losses in the satellite network. The above advantages makes SCTP an attractive transport protocol for wireless handheld devices.

Application of mobile-IP to space and aeronautical networks

NASA is interested in applying Mobile Internet Protocol (mobile-IP) technologies to its space and aeronautics programs. In particular, mobile-IP will play a major role in the Advanced Aeronautic Transportation Technology (AATT), the Weather Information Communication (WINCOMM) and the Small Aircraft Transportation System; (SATS) aeronautics programs. This paper describes mobile-IP and mobile-routers-in particular, the features, capabilities, and initial performance of the mobile-router is presented. The application of mobile-router technology to NASAs space and aeronautics programs is also discussed.

Large File Transfers from Space Using Multiple Ground Terminals and Delay-Tolerant Networking

Abstract-We use Delay-Tolerant Networking (DTN) to break control loops between space-ground communication links and ground-ground communication links to increase overall file delivery efficiency, as well as to enable large files to be proactively fragmented and received across multiple ground stations. DTN proactive fragmentation and reactive fragmentation were demonstrated from the UK-DMC satellite using two independent ground stations. The files were reassembled at a bundle agent, located at Glenn Research Center in Cleveland Ohio. The first space-based demonstration of this occurred on September 30 and October 1, 2009. This paper details those experiments.