RECENT worldwide explosion of mobile Cellular
system can be most effective key technology for
solution of telecommunication issue in the developing
world and rural area.
- Near future, Cellular will be expanded to every
city and town and major highway of developing
countries.
-
Then rural area can access to the Cellular through
radio relay station(s) (up to 180 km total radio
span in CDMA) if necessary: Cellular deployment
to the city and town make it possible. This is the
key for success of rural telecommunications.
Hence the main focal points for Rura
Telecommunication issues are –
Remarkable trends of wireless communications:
- Worldwide explosion of mobile services.
- Its Convergence with Internet and otherBroadband services.
Traffic capacities required for mobile systems:
Increasing year by year.
Efficient use of radio spectrum is the most
Important Issue.
SDR (SOFTWARE DEFINED RADIO)
___________________________________
Paper No 45C; Copyright © 2006 by the IETE. |
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Technology will play an important role in thisissue, as an essential tool applied to such technologies:
- Dynamic spectrum allocation,
- Spectrum resource sharing
Spectrum Shortcoming Important Issue for
Mobile Services
- 1G: started using 800/900MHz bands with
partially 450MHz band.
- 2G: basically 1G bands; adding 1.8/1.9 GHz
bands.
Allocated bandwidth: 25-40MHz for each
up/downlink in 1-2G.
3G, ITU ALLOCATED 230 MHz IN TOTAL
WITHIN 2GHz BAND BY WRC’92, ADDED
TOTAL 519 MHz WITHIN 0.85/1.8/2.6GHz
BANDS
4G may use 3-4GHz bands
Simply looking above frequency extension to
higher and higher, it seems as if the spectrum issue
would never occur. But realities are as follows:
Restriction of calls
Often done in India when a concentration of calls
is predicted, such as; new year’s greetings, peak demand
hour during day (8-10AM) and evening time (5-8PM),
disaster, as against the demand ‘anytime’. |
