SUMMARY We propose a novel channel model of satellite-to-ground optical transmission to achieve a global-scale high-capacity communication network. In addition, we compose an effective channel coding scheme based on low-density generator matrix (LDGM) code suitable for that channel. Because the first successful optical satellite communication demonstrations are quite recent, no practical channe...

Routing in Low-earth-orbit (LEO) satellite system involves the choice of inter-satellite links (ISLs) that connects two home satellites of the mobile terminals. We use a mesh model to formulate the LEO system and proposed 4 mesh-based algorithms. The objective is to minimize the new call blocking probability and the forced termination probability. Also, due to the dynamic topology of the LEO sy...

To assist in the design and understanding of future global networks, this paper describes the practical and simulation experiences gained from a TCP/IP on ATM network over a high speed satellite link and presents performance comparison studies of such networks with the same host/traffic configurations over local area (LAN) and wide area (WAN) networks. It was found that the satellite systems de...

We study the impact of reliability mechanisms introduced at the link layer on the performance of transport protocols in the context of 4G satellite links. Specifically, we design a software module that performs realistic analysis of the network performance, by utilizing real physical layer traces of a 4G satellite service. Based on these traces, our software module produces equivalent link laye...

The paper is concerned with determining the feasibility of performing telesurgery over long communication links. It describes an experimental testbed for telesurgery that is currently available in our laboratory. The tesbed is capable of supporting both wired and satellite connections as well as simulated network environments. The feasibility of performing telesurgery over a satellite link with...

Ki-Dong Lee et al. 211 This paper presents a dynamic resource allocation algorithm with multi-frequency time-division multiple access for the return link of interactive satellite multimedia networks such as digital video broadcasting return channel via satellite systems. The proposed timeslot assignment algorithm, called the very efficient dynamic timeslot assignment (VEDTA) algorithm, gives an...

A small (1-V) modulation of the spacecraft potential is observed on the SCATHA satellite through its effects on the data from four instruments: two particle detectors and two field detectors. We show that there is a strong causal link between the modulation of the potential at this 1-V level and a nonuniform distribution of the photoemissive properties of the conducting material on the surface ...

There are many types of Performance Enhancing Proxies (PEPs). Different types of PEPs are used in different environments to overcome different link characteristics which affect protocol performance [1]. The main examples concerns satellite and wireless networks, which represent the most challenging environments. In the following, the main concepts representing the state of the art of the PEP wi...

Geostationary satellite links have characteristics that can degrade the performance of TCP. The propagation time for a geostationary satellite link is on the order of 0.25 seconds. Thus a satellite can add approximately 0.5 seconds to the round trip time experienced by a TCP packet and the corresponding acknowledgement. This delay time is the primary cause of TCP inefficiency over satellites. T...

Two-Way Satellite Time and Frequency Transfer (TWSTFT) links were first introduced to Coordinated Universal Time (UTC) generation in 1999. These TWSTFT links were calibrated by alignment with the corresponding GPS time links, of which the nominal uncertainty was 5 ns. In the past decade, the primary calibration technique for TWSTFT link calibrations was based on a TWSTFT mobile ground station (...