Why 800MHz?
Hi friends.Welcome to my new post . This time i came with a topic on Cellular mobiles
Now a days Mobile phone is common thing for every one.At least there is one mobile for every 50 peoples in our country. So we should learn about mobile communication and its frequencies.
Why people are going for these Cellular Mobile Phones, rather than using conventional mobile telephone systems ?
Because conventional mobiles have below limitations
Because conventional mobiles have below limitations
- Limited Service Capability
- Poor service Performance
- Inefficient spectrum Utilization
Here Spectrum utilization plays important role in today's scenario ,as number of users increasing rapidly from day to day
So let us talk about Spectrum using in Cellular Communication
In Cellulars we are using 800MHz. there is a story behind this.Today i will tell you about that
We have FCC , Which is known to be as Federal Communication Commission.This FCC decides everything for cellulars.It Made a decision for using 800MHz in Cellular communication
The FCC's decision to choose 800MHz was made because of severe spectrum limitations at lower frequency bands.
FM broadcasting services operate in the vicinity of 100MHz.
The Telivision broadcasting service starts at 41MHz and extends up to 960MHz.
Air-to-ground systems use 118 to 136MHz;military aircraft use 225 to 400MHz.The maritime mobile service is located in the vicinity of 160MHz.Also fixed-station services are allocated portions of the 30 to 100-MHz band. Therefore, it was hard for FCC to allocate a spectrum in the lower portions of the 30- to 400-MHz band since the spectrum in the lower portions of the 30- to 400-MHz band since the services of this band had become so crowded. On the other hand, mobile radio transmission cannot be applied at 10GHz or above because severe propagation path loss, multipath fading, and rain activity make the medium improper for mobile communications.
Fortunately, 800 MHz was originally assigned to educational TV channels. Cable TV service became a big Factor in the mid-70s and shared the load of providing TV channels. This situation opened up the 800-MHz band to some extent, and the FCC allocated a 40-MHz system at 800 MHz to mobile radio cellular systems.
Although 800 MHz is not the ideal transmission medium for mobile radio, it has been demonistrated that cellular mobile radio system that does not go beyond this frequency band can be deployes. Needless to say, the medium of trasmitting an 800-MHz signal, although it is workable, is already very difficult.
So let us talk about Spectrum using in Cellular Communication
In Cellulars we are using 800MHz. there is a story behind this.Today i will tell you about that
We have FCC , Which is known to be as Federal Communication Commission.This FCC decides everything for cellulars.It Made a decision for using 800MHz in Cellular communication
The FCC's decision to choose 800MHz was made because of severe spectrum limitations at lower frequency bands.
FM broadcasting services operate in the vicinity of 100MHz.
The Telivision broadcasting service starts at 41MHz and extends up to 960MHz.
Air-to-ground systems use 118 to 136MHz;military aircraft use 225 to 400MHz.The maritime mobile service is located in the vicinity of 160MHz.Also fixed-station services are allocated portions of the 30 to 100-MHz band. Therefore, it was hard for FCC to allocate a spectrum in the lower portions of the 30- to 400-MHz band since the spectrum in the lower portions of the 30- to 400-MHz band since the services of this band had become so crowded. On the other hand, mobile radio transmission cannot be applied at 10GHz or above because severe propagation path loss, multipath fading, and rain activity make the medium improper for mobile communications.
Fortunately, 800 MHz was originally assigned to educational TV channels. Cable TV service became a big Factor in the mid-70s and shared the load of providing TV channels. This situation opened up the 800-MHz band to some extent, and the FCC allocated a 40-MHz system at 800 MHz to mobile radio cellular systems.
Although 800 MHz is not the ideal transmission medium for mobile radio, it has been demonistrated that cellular mobile radio system that does not go beyond this frequency band can be deployes. Needless to say, the medium of trasmitting an 800-MHz signal, although it is workable, is already very difficult.
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