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Microwave 2.1 2.2
- 2. 2 Is simply a high radio frequency link specifically designed to provide signal connection between two specific points. Also coined as Line-of- Sight or LOS communications, Radio Link, Point-to-Point communications. Electromagnetic waves with frequencies that range from approximately 500 MHz to 300 GHz or more. λ = c / f .The wavelengths for microwave frequencies fall between 1 cm and 60 cm.
- 3. 3What is MICROWAVE RADIO COMMUNICATION? A communication system that utilizes the radio frequency band spanning 2- 60 GHz. As per IEEE, EM waves between 30 and 300 GHz are called millimeter waves (MMW) since their wavelengths are about 1 -10mm.
- 4. Microwave Radio Communication… The beginning..
- 5. The Power of PowerPoint - thepopp.com 5 Western Union sends the first successful microwave message between New York and Pennsylvania First transcontinental microwave radio system began operation. United States was completely covered by microwave relay stations. The first digital microwave communication towers were developed for small- and medium-capacity networks, eventually expanding to cover the entire United States. 1945 1951 1960s 1970s
- 6. Figure 1: Siae 7.5GHz 16 x 2Mbps digital microwave radio system - all indoor solution late 1980s mid 1990s mid 1990s) Figure 2: PCOM IDU, frequency independent IDU with 16 x 2Mbps ports (tribs) - split mount systems (IDU/ODU) Figure 3: PCOM ODU, 13GHz ODU - split mount systems (IDU/ODU), with waveguide between ODU and antenna 6 Figure 4: Plesiochronous Digital Hierarchy (PDH) multiplexing
- 7. 7 Figure 5: Microwave radio tower with a class 1 parabolic antenna and a class 2 parabolic antenna Figure 6: Microwave radio tower with cellular antennas and a large quantity of class 3 antennas
- 8. Table 1 lists some of the microwave radio-frequency bands available in the United States. 8
- 10. 01 02 03 The Power of PowerPoint - thepopp.com 1 0 o Nature Analog Digital o Distance / Frequency Short Haul Medium Haul Long Haul o Capacity / Bandwidth Light (Narrow Band) Medium (Narrow Band) Large (Wide Band)
- 11. The Power of PowerPoint - thepopp.com Each station requires the purchase or lease of only a small area of land. Radio systems do not require a right-of- way acquisition between stations. Because of their high operating frequencies, microwave radio systems can carry large quantities of information. High frequencies mean short wavelengths, which require relatively small antennas. Radio signals are more easily propagated around physical obstacles such as water and high mountains. Fewer repeaters are necessary for amplification.
- 12. The Power of PowerPoint - thepopp.com Distances between switching centers are less. Underground facilities are minimized. Minimum delay times are introduced. Minimal crosstalk exists between voice channels. Increased reliability and less maintenance are important factors.
- 13. The Power of PowerPoint - thepopp.com It is more difficult to analyze and design circuits at microwave frequencies. Measuring techniques are more difficult to perfect and implement at microwave frequencies. It is difficult to implement conventional circuit components (resistors, capacitors, inductors, and so on) at microwave frequencies. Transient time is more critical at microwave frequencies. It is often necessary to use specialized components for microwave frequencies. Microwave frequencies propagate in a straight line, which limits their use to line-of-sight applications.
- 14. ANALOG vs. DIGITAL MICROWAVE
Editor's Notes
- Microwaves are used in a lot of technologies from mobile phones to satellites and home appliances. A lot of industries rely on microwaves to transmit data and still one of the most viable technologies for a lot of industries.
- Before we go deeper in Microwave Radio Communication let us go back to its History or the Timeline.
- As higher frequency systems were developed it became obvious that large all indoor solutions would not be possible since the attenuation within the waveguide increases significantly with frequency. The solution to this challenge was to split the microwave radio system into an indoor unit (IDU) containing the baseband and modem, connected to an outdoor unit (ODU) containing the microwave transceiver with frequency up-conversion and power amplification in the transmit path, and low noise amp and down converter on the receive side.
- microwave communications systems requires full-duplex (two-way) operation, each frequency band is divided in half with the lower half identified as the low band and the upper half as the high band. At any given radio station, transmitters are normally operating on either the low or the high band, while receivers are operating on the other band.
- Figure 1 shows a typical layout for a microwave radio link. Information originates and terminates at the terminal stations, whereas the repeaters simply relay the information to the next downlink microwave station. Figure 1a shows a microwave radio link comprised of two terminal stations (one at each end) that are interconnected by three repeater stations. As the figure shows, the microwave stations must be geographically placed such that it does not interfere with transmissions between stations. This sometimes necessitates placing the stations on top of hills, mountains, or tall buildings. Figure 1b shows how a microwave radio link appears from above. Again, the geographic location of the stations must be carefully selected such that natural and man-made barriers do not interfere with propagation between stations. Microwave radios propagate signals through Earth’s atmosphere between transmitters and receivers often located on top of towers spaced about 15 miles to 30 miles apart. Therefore, microwave radio systems have the capacity to carry thousands of individual information channels between two points without the need for physical facilities such as coaxial cables or optical fibers.
- Microwave radio Communication uses Microwaves to send data either in short haul or long haul systems. But in the age of Wifi, 3G and LTE (Long Term Evolution), why do we still need to use Microwave Radio Communication?
- >Right-of-way – a legal right of passage over another person’s ground. >This is Because Microwave Radio Communication is powerful enough not to need massive towers. >This means that it is very cost efficient to use microwave radio communications for a lot of systems for business or enterprise. >Microwaves operate at very high frequencies so they travel much faster and require only smaller infrastructure to transmit. >Water and high mountains may interfere with other kinds of signals. Microwaves travel better through them because they are so robust (strongly formed). >Thus Microwaves are much cheaper
- Microwave Radio Communication are more reliable since they require less maintenance. This means that it is cheaper to keep up a microwave radio station than any othr kind of station.
- >Signals that have been transmitted moves so quickly and carries a lot of information thus it requires meticulous circuitry to utilize the microwave frequencies. >usually, you need to hear the reception yourself instead of relying on the data transmitted with the signal. >That is why businesses and enterprises ends up asking engineering firms to design and customize their own transmitters and receivers. > >Despite being able to travel through many mediums without compromising the stored data, they can only travel in straight line. Thus you need to broadcast or retransmit multiple times in several directions to propagate a signal. That is why microwaves in space are hard to capture that brings excitement to scientists. Keep in mind that the software used for controlling the waves of the microwave radio communication needs variety of devices to work best. From Multiplexers, Filters, Amplifiers, Oscillators, Frequency Multipliers, couplers, and links.
- A vast majority of the existing microwave radio systems are frequency modulated which is analog, thru time because of the improvisation they developed the use of either PSK(Phase Shift Keying) or QAM (Quadrature Amplitude Modulation) which are digital. Let me just show you the comparison between analog and digital in terms of transmitting data.