1. Lec 17 Wireless Computer Networks Al-Mustansiryah University
Elec. Eng. Department College of Engineering Fourth Year Class
Lec 17
Wireless

2. 5-2 UNGUIDED MEDIA: WIRELESS
Unguided media transport electromagnetic waves without using a physical conductor. This type of communication is often referred to as wireless communication.
Figure Electromagnetic spectrum for wireless communication

3. Figure 5.13 Wireless transmission waves

4. Radio waves are used for multicast communications, such as radio and television, and paging systems.
They can penetrate through walls.
Use omni directional antennas

5. Figure 5.14 Omni directional antenna

6. Microwaves are used for unicast communication such as cellular telephones, satellite networks, and wireless LANs.
Higher frequency ranges cannot penetrate walls.
Use directional antennas - point to point line of sight communications.

7. Figure 5.15 Unidirectional antennas

8. Infrared signals can be used for short-range communication in a closed area using line-of-sight propagation.