1. Day 6 Wireless Media

2. Frequencies Spectrum of frequencies divided up –Frequencies are assigned by FCC for task Radio Phones Microwave Satellite communication Light XRay Gamma Ray

3. Radio AM750 –750,000 Hz –50,000 Watt –Clear Channel Local, Regional, Clear Channel –Omni directional

4. Analogue Cell phones Cells –1 block (1/2 mile) – 50 miles –Adjacent blocks use different frequencies –Low power transmission ensures no crosstalk –Setup channel Sends signal that phone is on and in this cell area Used when dialing a number Used to receive a call –Technologies Advanced Mobile Phone Service (AMPS) –Frequency Division Digital-Advanced Mobile Phone Service (DAMPS) –Frequency and Time Division

5. Digital Cells PCS – 2 nd generation –Code Division Multiple Access (CDMA) Verizon, Sprint, –Global System for Mobile Communication (GSM) [also time division] Uses TDMA (Time division multiple access) Tmobile, Cingular (AT&T)

6. Bluetooth (802.15.1) 2.45Ghz –Rotates over 79 channels ever 1/1600 second Class 1 –100M Class 2 –10M Class 3 –1M Can transmit through objects V1, 1.1, 1.2: 721,000 bits/second –Most current phones/earpieces are 1.2 V2: 2.1mbps

7. 802.11 B –11Mbps (max), 6.5Mbps (norm) –2.4Ghz –Range 100 feet A –54Mbps (max), 25Mbps (norm) –5.3Ghz –Range 100 feet G –54Mbps (max), 25Mbps (norm) –2.4Ghz –Range 100 feet N –540Mbps (max), 200Mbps (norm) –2.4Ghz or 5Ghz –Range 160 feet

8. Microwave 100,000,000Hz – 1,000,000,000Hz (Ghz) Used all the time in rural and urban areas –Directional and line of sight –Range 15-30 miles Bad in snow, rain Can be blocked by buildings, trees etc.

9. Satellite Up and down to satellite –Can send signals long distances around earth –2,500 in orbit today –http://science.nasa.gov/Realtime/jtrack/ 3d/JTrack3D.htmlhttp://science.nasa.gov/Realtime/jtrack/ 3d/JTrack3D.html

10. Orbit Close (Low Earth Orbit LEO) –100 – 1000 Miles –Less propagation delay –Constantly must orbit Changes position Passes over point 15-16 times/day Middle-Earth-Orbit (MEO) –1000 – 22,300 miles –GPS (29 satellites) Each circles earth twice per day @ 12,600 miles 4 satellites are in line of sight always from anywhere on earth Each contain an atomic clock 1575.42Mhz

11. Geosynchronous Stays in same position over earth –22,300 miles out 0.25 seconds to reach & return from satellite –Easy to transmit to because you only have to lock on once, no tracking –If over equator they don’t move from the prospective of the earth. –If not over equator, they oscillate and require a tracking motor to keep a lock on

12. Infrared Remote controls IR ports on laptops, printers etc. Close range only –Typically <5 feet Line of sight only Low bandwidth –Typically 9600baud –Can be as high as 16Mbps

13. Laser Without fiber can be used to transmit Not very popular Can be very high speed Line of sight

14. Choice Decision Cost –Installation –Maintenance –Right of way Speed –Max data transfer speed –Propagation speed Distance –Choice of wire/wireless –Interference Environment –Wind, rain, snow, sunspots Security –Wiretapping