Có 28+ tài liệu thuộc chủ đề "tín hiệu kênh"
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21.1 INTRODUCTION. Mobile ad hoc networks consist of wireless hosts that communicate with each other in the absence of a fixed infrastructure. Thus, routes between two hosts in a network may consist of hops through other hosts in the network. The task of finding and maintaining routes in the network is nontriv- ial since host mobility causes frequent unpredictable topological...
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22.1 INTRODUCTION. One of the major advantages of LEO satellites (as opposed to geostationary—GEO—satellites) is that they are closer to the Earth’s surface. Second, the footprint of each satellite moves continuously, implying a high mobility of the whole network, in contrast with other cellular systems.. 22.2 TOPOLOGIES. All such factors determine the topology of the network, as shown in this...
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In the case of IP, for example, the datagram is not guaranteed to arrive intact at all members of the destination group or in the same order relative to other datagrams [1].. The multicast service is critical in applications characterized by the close collaboration of teams (e.g., rescue patrols, mil- itary battalions, scientists, etc.) with requirements for audio and video...
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Broadcasting is one of the fundamental tasks in network communication. Its goal is to transmit a message from one node of the network, called the source, to all other nodes.. Every node can reach a given subset of other nodes, de- pending on the power of its transmitter and on the topographic characteristics of the sur- rounding region.. Nodes of...
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The mobile node uses two IP ad- dresses: a fixed home address and a care-of address that changes at each new point of at- tachment.. Packets destined to a mobile node are routed first to their home network—a network identified by the network prefix of the mo- bile node’s (permanent) home address. At the home network, the mobile node’s home...
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26.1 INTRODUCTION. The field of mobile computing is the result of the merger of these advances in computing and communication with the aim of providing a seamless and ubiquitous com- puting environment for mobile users. In mobile computing, however, these problems become more difficult to solve, mainly because of the narrow bandwidth of the wireless communication channels, the relatively short...
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27.1 INTRODUCTION. In this chapter, we review the main characteristics of applications of pervasive comput- ing in Section 27.2, discuss the architecture of pervasive computing software in Section 27.3, and review key open protocols in Section 27.4.. 27.2 PERVASIVE COMPUTING APPLICATIONS. Context awareness translates to adaptation of the behavior of an application as a func- tion of its current environment....
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28.1 INTRODUCTION. Another major factor that presents a real opportunity for data networking in indoor environments is the massive growth and usage of the Inter- net. These users might need to send data files to each other, run some local applications or use any of the existing internet-based applications available on wired terminals located within their range. Some of the...