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EVOLUTION OF WIRELESS COMMUNICATION

EVOLUTION OF WIRELESS COMMUNICATION. SHUSHRUTHA K S. AMPS. The Advanced Mobile Phone System is one of the earliest commercial cellular systems.

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EVOLUTION OF WIRELESS COMMUNICATION

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  1. EVOLUTION OF WIRELESS COMMUNICATION SHUSHRUTHA K S

  2. AMPS • The Advanced Mobile Phone System is one of the earliest commercial cellular systems. • AMPS technology is currently deployed throughout North America and AMPS-derivative systems are deployed in a majority of worldwide cellular markets • AMPS was invented at Bell Labs and initially deployed in the U.S. in the early 1980

  3. AMPS -FEATURES • Analog FM modulation • Frequency allocated for AMPS is 824-849 MHz for downlink and 869-894 MHz for uplink traffic. • RF bandwidth 30 kHz. • The band can accommodate 832 duplex channels, among which 21 are reserved for call setup, and the rest (811)for voice communication. • Available in U.S., Canada, Hong Kong, New Zealand, Thailand • A narrowband versus exists with a 10 kHz channel spacing, such that 2496 channels can be assigned, in stead of 832 for the normal AMPS mode.

  4. AMPS-CHANNELS • Each physical channel is 30 kHz wide and is dedicated to a single mobile station for the duration of the call while the mobile is in the current cell. • Each call uses a dedicated forward channel paired with a dedicated reverse channel at a 45 MHz offset. Some of the channel pairs (21 of them) are used for control purposes in the AMPS environment. • Analog frequency modulation (FM) with 8 kHz deviation is used in the traffic channels, which convey voice conversations. • Binary frequency shift keying (FSK) at 10 kbps-a digital modulation technique-is used in the control channels used for signalling. • AMPS channels can suffer from interference, which sounds like static to a user; analog signals suffering from multipath fading cannot be corrected. • Finally, AMPS radio resource management is based on signal strength,

  5. AMPS - ROAMING • Since no cellular service provider covers the entire country, • Mobile carriers must provide service to one another's customers for those customers to be able to receive service whenever they are outside of their home area. This capability to receive service while in another service provider's domain is called roaming. • All signalling between systems was proprietary in nature and the roaming capability had to be manually administered. • In early years, intercarrier business relationships sometimes abused the customers' need for roaming, with service providers sometimes surprising subscribers with excessive "roaming charges." This has cost the cellular industry much in terms of reputation and customer relations.

  6. AMPS CELLULAR OPERATION

  7. AMPS CELLULAR OPERATION • 21 predefined control channels. • System identification or SID of the MSC • Registers • Mobile identification number • Electronic serial number

  8. Reference • http://www.leapforum.org/published/internetworkMobility/split/node37.html

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