ADMS 2511 Chapter 6: wireless, mobile computing, and mobile commerce
11 Feb 2017
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Adms 2511 ch 6 wireless, mobile computing, and mobile commerce. Enables working time scheduled customized: wireless devices. Small enough to easily carry or wear. Sufficient computing power to perform productive tasks. Communicate wirelessly with internet and other devices. Copy and pass confidential information: wireless transmission media. Transmits data via electromagnetic waves: used for high volume, long distance. Line of sight communications: transmitter/receiver must be in view of each other. Limited to usually 50km apart due to curved earth. Three types of satellites around earth: geostationary (geo, medium earth orbit (meo, low earth orbit (leo) Receives signals through line of sight: but footprints is larger the further away from earth it is. Also use broadcast transmission: sends signals to many receivers at once. Geo: 35,900km above earth, maintain fixed position, limitations. Takes quarter of a second to send and return. Meo: 10,354 km above earth, require more satellites than geo. No propagation delay: must be tracked.
