TAILIEUCHUNG - Lecture Wireless and mobile computing – Chapter 4: Transmission media

The following will be discussed in this chapter: Transmission media, transmission media classification, transmission media characteristics and design specifications, guided and unguided media, wireless transmission frequencies, antennas, wireless propagation. | Transmission Media Lecture 4 Overview Transmission media Transmission media classification Transmission Media characteristics and design specifications Guided and Unguided media Wireless Transmission Frequencies Antennas Wireless Propagation 1 Transmission Media The transmission medium is the physical path by which a message travels from sender to receiver. Computers and telecommunication devices use signals to represent data. These signals are transmitted from a device to another in the form of electromagnetic energy. Examples of Electromagnetic energy include power, radio waves, infrared light, visible light, ultraviolet light, and X and gamma rays. All these electromagnetic signals constitute the electromagnetic spectrum 2 Electromagnetic Spectrum 3 Not all portion of the spectrum are currently usable for telecommunications Each portion of the spectrum requires a particular transmission medium Transmission Media Classification 4 Guided media, which are those that provide a conduit from one device to another. Examples: twisted-pair, coaxial cable, optical fiber. Unguided media (or wireless communication) transport electromagnetic waves without using a physical conductor. Instead, signals are broadcast through air (or, in a few cases, water), and thus are available to anyone who has a device capable of receiving them. Transmission Media Classification 5 Characteristics and quality determined by medium and signal For guided, the medium is more important For unguided, the bandwidth produced by the antenna is more important Key concerns are data rate and distance 5 Transmission Media Classification One key property of signals transmitted by antenna is directionality. In general, signals at lower frequencies are omnidirectional; that is, the signal propagates in all directions from the antenna. At higher frequencies, it is possible to focus the signal into a directional beam 6 6 Transmission Media Classification 7 Signals of low frequency (like voice signals) are .

• Quản trị mạng
• Mobile computing
• Wireless and mobile computing
• Services data
• Wireless communication
• Transmission media
• Wireless propagation
• Transmission fundamentals
• Mobile computing transmission fundamentals
• Mobile computing simulations
• Network simulation
• Addressing routing
• Visualization tool
• Signals for conveying information
• Digital data transmission
• Mobile systems
• Mobile services
• Lecture Electronic commerce
• Electronic commerce
• Define mobile commerce
• Personal digital assistant
• Wireless mobile computing
• Lecture Mobile applications overview
• Mobile applications overview
• Mobile computing devices
• Mobile applications becoming ubiquitous
• Mobile cloud computing
• Mobile web services
• Cloud computing
• Medical cloud multi agent system
• New mobile medical
• Introduction to Mobile Cloud Computing
• MCC Architecture
• Advantages of MCC
• MCC Applications
• MCC Issues
• Error control
• Digital communication system
• Error detection
• Cyclic Redundancy Check
• Software defined radio
• Satellite communications
• Satellite foot print
• Wireless LAN technology
• Electromagnetic radiation spectrum
• Wireless media standards
• Requirement of protocol
• OSI model
• Protocol suit
• Network access layer
• Transport layer