SUMMARY This paper proposes the concept of adaptive multi-rate (AMR), which jointly employs switching between two links and adaptive rate on each link, for hybrid free-space optical/radio-frequency (FSO/RF) systems. Moreover, we present the cross-layer design of AMR switching, which is based on both the physical and link layers with an automatic-repeat request (ARQ) scheme. We develop an analyt...

This paper presents a combination of Free Space Optic systems with WLAN and Satellite Communications to provide Video conferencing and data transfer for use in Civil Military Cooperation and disaster recovery applications. A modular communication system developed at TU Graz is described, which facilitates worldwide access to the Internet or any other network (depending on the particular applica...

The BER and the availability belong among the basic qualitative parameters of free space optical (FSO) links. The BER parameter is usually mentioned by FSO manufacturers, but it is not defined what conditions a certain value of BER stands for. This article deals with problems of measuring the BER of free space optical link and with questions how to determine the probability of unavailability of...

The increase of data-rates that are provided by free-space optical (FSO) communications is essential in our data-driven society. When used satellite and interplanetary networks, these links can ensure fast connections, yet they susceptible to atmospheric disruptions long orbital delays. Delay Disruption Tolerant Networking (DTN) architecture ensures a reliable connection between two end nodes, ...

Free space optics (FSO) has been recognized as a crucial technique to meet the high-bandwidth requirements in future wireless information transmission links. It provides feasible solution last-mile bottleneck problem due its merits that include high-speed data transportation and secure low-latency networks. Due these merits, FSO is reliable technology for health-care biomedical services like of...

Free-space optical (FSO) systems are able to offer the high data-rate, secure, and cost-efficient communication links required for applications such as wireless front- backhauling 5G 6G networks. Despite substantial advancement of FSO over past decades, requirement a line-of-sight connection between transmitter receiver remains key limiting factor their deployment. In this article, we discuss p...

Free-space optical (FSO) communications using intensity modulation and direct detection (IM/DD), is a cost-effective and high bandwidth access technique, which has recently received significant attention and commercial interest for a variety of applications [30, 44]. Optical wireless communication systems are rapidly gaining popularity as effective means of transferring data at high rates over ...

Title of Document: TOPOLOGY CONTROL AND POINTING IN FREE SPACE OPTICAL NETWORKS Yohan Shim, Doctor of Philosophy, 2007 Directed By: Associate Professor Steven A. Gabriel Department of Civil and Environmental Engineering Free space optical (FSO) communication provides functionalities that are different from fiber optic networks and omnidirectional radio-frequency (RF) wireless communications in ...

Radio frequency-based communication has been the dominant way of wireless networking throughout the last two decades. Although new medium access control (MAC) technologies have been adapted to provide better per-node throughput, we have arrived to a point where the frequency spectrum saturates because of the overwhelmingly high data load caused by ever-increasing usage of multimedia content. To...

Because of its high directivity, free-space optical (FSO) communication offers a number advantages. It can, however, give rise to major system difficulties concerning alignment between two terminals. During the link-acquisition step (a.k.a. coarse pointing), ground station can be prevented from acquiring links due pointing errors and insufficient information about unmanned aerial vehicle locati...