1G - Mobile voice

First-Generation Analog

Advanced Mobile Phone Service (AMPS).

• In North America, two 25-MHz bands allocated to AMPS.

  • One for transmission from base to mobile unit.

  • One for transmission from mobile unit to base.

• Each band split in two to encourage competition.

• Frequency reuse exploited.

Characterization

Most popular 1G system during 1980s

• Advanced Mobile Phone System (AMPS).

• Nordic Mobile Phone System (NMTS).

• Total Access Communication System (TACS).

• European Total Access Communication System (ETACS).

Key features (technology) of 1G system

• Frequency 800 MHz and 900 MHz.

• Bandwidth: 10 MHz (666 duplex channels with bandwidth of 30 KHz).

• Technology: Analogue switching.

• Modulation: Frequency Modulation (FM).

• Mode of service: voice only.

• Access technique: Frequency Division Multiple Access (FDMA).

Disadvantages of 1G system

• Poor voice quality due to interference.

• Poor battery life.

• Large sized mobile phones (not convenient to carry).

• Less security (calls could be decoded using an FM demodulator).

• Limited number of users and cell coverage.

• Roaming was not possible between similar systems.