one of the limitations of orthogonal frequency division multiplexing (ofdm) in many applications is its sensitivity to frequency shifts, errors normally referred to as carrier frequency offset (cfo). although, this small offset is negligible in conventional single carrier communication systems, it is a severe problem in the ofdm systems. because, the carriers in ofdm are inherently closely spac...

— This paper discusses the characteristics of a space-to-space multiple-input, multiple-output (MIMO) communication channel that distinguish it from more common terrestrial MIMO communication channels. These characteristics imply that the channel matrices for space communication channels have a particularly simple structure that leads to statistical characteristics that are both predictable and...

This paper is motivated by exploring the impact of the number of channels on the achievable communication latency for a specific communication task. We focus on how to utilize the multiple channels to speed up four group communications including broadcast, aggregation, gathering, and gossiping in wireless networks under protocol interference model. Four scheduling algorithms are developed for t...

Modern computer-supported cooperative work applications (CSCW) supporting same-time/di erentplace interaction are required to open several communication channels. Each of these channels has its own Quality of Service (QoS) and is implemented by a speci c protocol stack. Typically, these channels need to be synchronized but inter-stack dependencies are hard to express with current communication ...

Given the possibility of communication systems failing catastrophically, we investigate limits to communicating over channels that fail at random times. These channels are finitestate semi-Markov channels. We show that communication with arbitrarily small probability of error is not possible. Making use of results in finite blocklength channel coding, we determine sequences of blocklengths that...

We discuss the challenge of scalable dissemination approach in a world where the number of communication channels and interaction possibilities is growing exponentially, particularly on the Web, Web 2.0, and semantic channels. Our goal is to enable smaller organizations to fully exploit this potential. We have developed a new methodology based on distinguishing and explicitly interweaving conte...

Distributed computing and parallel computing study different kinds of systems, but they both study concurrent algorithms that run on collections of processors. In parallel computing, processors are tightly coupled, which usually means they move in lockstep, communication between processors is fast, and neither processors nor communication channels suffer from errors. By contrast, in a distribut...

1 Communication channels are major components of computer communication networks. They provide the physical mediums over which signals, representing data, are transmitted from one node of the network to another node. Communication channels can be classiied into two main categories: point-to-point channels and shared channels. Typically, the backbone of wide area networks (WANs) consists of poin...

The creation of covert channels in public computer networks can prove an effective means of information hiding and secret communication. With the widespread adoption of the Internet the TCP/IP suite of protocols have become pervasive, and therefore an attractive target for covert channel exploitation. This paper gives a brief overview of covert channels in communication networks, and presents a...