In recent years, wireless indoor networks have received a lot of scientific and industrial attention. Most systems rely on the use of Orthogonal Frequency Division Multiplexing (OFDM) because of its capability to elegantly cope with multi-path interference. However, while OFDM provides a nice solution for the digital modem, its front-end requirements should be investigated as well. To that goal...

This paper presents the validation methodology established and applied during the development of a wireless LAN application. The target of the development is the implementation of the hardware physical layer of the HIPERLAN/2 wireless LAN protocol and its interface with the upper layers. The implementation of the physical layer (modem) has been validated in two different levels. First, at the f...

During the last 2-3 years, there has been a lot of activities aiming to deploy broadband wireless access systems. The US LMDS auctions in February-March 1998 of 1.3 GHz of spectrum between 27.5 GHz and 31.3 GHz triggered e orts to develop system solutions and standards that have as objective to render LMDS systems competitive to other broadband, and primarily wireline, technologies. The modem d...

Satellite operators have recently begun offering Internet access over their networks. Typically, users connect to the network using a modem for uplink, and a satellite dish for downlink. We investigate how the performance of these networks might be improved by two simple techniques: caching and use of the return path on the modem link. We examine the problem from a theoretical perspective and v...

Brian Tierney has established himself over the course of forty-five years of writing and teaching as one of the world's leading authorities on the history of medieval canon law and political thought. In a series of foundational works, he has offered important new interpretations of the origins of Western constitutionalism, tracing many concepts believed to be modem or early modem innovations to...

The demands currently placed on medium data rate digital transmission services are for increased spectral eeciency and this factor leads to the development of innovative high speed modem archi-tectures. This paper discusses various aspects of the modem development currently being under-taken by the Institute for Telecommunications Research (ITR) at the University of South Australia (USA) in col...

In this paper, we analyze the effects of the distinction between long and short data grants in the Data Over Cable Service Interface specifications (DOCSIS) protocol. According to DOCSIS specifications, the grants for a bandwidth request of a cable modem can be for either short or long data packets. The threshold value classifying a short and long data packet is a system operation parameter and...

Today, underwater acoustic communication is developing for its various applications. For signal transmission in underwater using ocean/ sea/lakes/rivers as a medium an appropriate underwater acoustic system is required. The significant characteristic of ocean makes the underwater communication difficult using electromagnetic waves. The characteristics of an acoustic signal make a good candidate...

To create and demonstrate a reactive survey system, capable of long-term unattended deployments in harsh environments. We refer to such a system as an Autonomous Ocean Sampling Network (AOSN). The goal of the Utility Acoustic Modem effort is to develop a low-power hardware platform and a robust signaling strategy for data communications between components such as robotic vehicles, moorings, or ...