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Wireless & Mobile Networking: Mobile Radio Propagation. Azizol Bin Abdullah email@example.com (A2.04). Outline. Revisit: Wireless communication -What is radio waves? Types of radio waves Propagation Mechanisms. Wireless Communication. Wireless communication:
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Azizol Bin Abdullah
is transferring of information over electromagnetic waves over atmospheric space(as opposed to long cable)
-Light, microwaves, x-rays, TV and radio transmissions are all kinds of electromagnetic waves.
The electromagnetic spectrum is the distribution of electromagnetic radiation according to energy.
Extremely Low Frequency
3 - 30 Hz
100,000 - 10,000 km
Super Low Frequency
30 - 300 Hz
10,000 - 1,000 km
Ultra Low Frequency
300 - 3000 Hz
1,000 - 100 km
Very Low Frequency
3 - 30 kHz
100 - 10 km
30 - 300 kHz
10 - 1 km
300 - 3000 kHz
1 km - 100 m
3 - 30 MHz
100 - 10 m
Very High Frequency
30 - 300 MHz
10 - 1 m
Ultra High Frequency
300 - 3000 MHz
1 m - 10 cm
Super High Frequency
3 - 30 GHz
10 - 1 cm
Extremely High Frequency
30 - 300 GHz
1 cm - 1 mm
Low frequency means big waves and high frequency equates to small waves. Higher frequency ‘short’ waves is better for long range transmission.
A service band has a specific
purpose, such as FM radio or
Service bands are divided into
channels. Signals sent in different channels do not interfere with one
Channels with wider bandwidths
can carry signals faster.
1. Global System for Mobile in the 900 MHz BandUpper band: 925 to 960 MHz Lower band: 880 to 915 MHz
a) Celcom Celcom ( Malaysia) Berhad
b) Maxis Maxis Mobile Sdn Bhd
c) DiGi DiGi Telecommunication Sdn Bhd
2. Global System for Mobile System in the 1800 MHz BandUpper band: 1805 to 1880 MHz Lower band: 1710 to 1785 MHz
a) CELCOM MOBILE Celcom Mobile Sdn Bhd
b) MAXIS (MMS) Malaysian Mobile Services Sdn Bhd
c) DIGI DiGi Telecommunication Sdn Bhd
3. International Mobile Telecommunications-2000 (IMT2000)
Frequency Division Duplex (FDD)
Upper band: 2110 to 2170 MHzLower band: 1920 to 1980 MHz
Time Division Duplex (TDD)
Frequency: 1915 to 1920MHz Frequency: 2010 to 2025MHz
a) TM Telekom Malaysia Berhad
b) UMTS UMTS (Malaysia) Sdn Bhd
c) TT.COM TT Dotcom Sdn Bhd
d) MITV U Telecom Media Holdings Sdn Bhd
As the formula indicates, the wavelength of a radio signal decreases as its frequency increases.
Measured in Hertz (Cycles per Second)
2 Cycles in one Second, so 2 Hz
Wavelength * Frequency = Speed of Propagation
- Communication from/to a fixed station to/from a MS
- it becomes a multipath propagation channel with fading :- the signal reaches the destination using many different paths (diffraction and reflection)
- The signal strength and quality received varies according to the time
Wave propagation in the multipath channel depends on the actual environment such as:
- the antenna height
- building profile
- roads profile
- terrain profile
Wave propagation is characterized by three aspect:- path loss, slow fading and fast fading.
Path Loss (Lp)
- average propagation loss over a wide area
- it determine by the macroscopic parameter such as:- TR distance, carrier frequency, land profile.
Slow Fading (Ls)
- variation of propagation loss in local area(several 10m)/small area.
Fast Fading (Lf)
- the motion of the terminal in a standing wave that consist many diffracted waves
- the frequency of received signal will not be the same as the source when a wave source and a receiver are moving relative to one another.
- spreading effect :- reflections produce more path with different path length caused the arrival time of each path is different.
- caused by time delayed multipath signals. Also has an impact on the burst error rate of the channel.
- represent the correlation between two fading signal at different frequency
- caused by same frequency