Microwave systems transmit high-speed radio signals in a line of sight path between relay stations i.e transmission from one antenna to another usually placed on top of buildings, towers, hills and mountains peaks.
Microwave system transmits high-speed singles in a line of sight path relay stations spaced approximately 25 to 35 miles apart. It has much lower error rate and communication links can be made over large distance. simply, straight line through the air rather than through wires.
Networks using radio signal transmission do not require a direct physical connection between computer. Instead each participating computer attaches to an antenna, which can both transmit and receive radio signals.
Although radio transmission do not bend around the surface of the earth Radio frequency technology can be combined with satellites to provide communication across longer distance. Satellites have now become an integral part of the worldwide communication system. It is nothing more than microwave radio relay station.
They have the capability of a direct line of sight path and almost the earth’s entire surface. so, they can transmit high speed microwave or radio-signal to the transmitters on the ground (earth).
A ground station on one side of the ocean transmits a signal to the satellite. Which then sends the signal to a ground station on the other side. A single satellite usually contains multiple transponders device that consist of a radio receiver and transmitter that operate independently typically six to twelve.
Each transponder uses a different radio frequency, making it possible for multiple communications to proceeds simultaneously. This uses satellites orbiting 22000 miles above the earth for transmitting the data from relaying station at one end of the globe to the receiving station at the other end of the globe, it accounts for most long-distance international communication.
The wireless remote controls used with appliances such as televisions and stereos communicate with infrared transmissions. Infrared is limited to a small area (e.g a single room), and usually requires that the transmitter be pointed tower the receiver.
Infrared hardware is inexpensive compared to other mechanism, and does into require and antenna.
Computer networks can use infrared technology for data communication. For example, it is possible to equip a large room with single infrared connection that provide network access to all computer in the room.
Computers can remain in contact with the network while they are moved within the room infrared networks are especially convenient for small portable computers because infrared offers the advantages of wireless communications without requiring the use of antennas.
Bluetooth technology that enables short-range wireless connections between desktop and notebook computer, handhelds, personal digital assistants, mobile phones, camera phones, printers, digital cameras, headsets, keyboards and even a computer mouse.
Bluetooth wireless technology uses a globally available frequency band 2.4 GHz for worldwide compatibility with the 10 meter range.