(a)                First Generation (IG) System: These are voice oriented analog cellular and cordless telephones. These systems use two separate frequency bands for forward (from base station to mobile) and reverse (from mobile to base station) links. Such a system is referred to as frequency division duplex (FDD) scheme. The typical allocated overall band in each direction was25 KHz. The dominant spectra of operation for these systems were the 800 and 900 MHz bands. All the first generation   (IG) system use analog frequency modulation for which the transmission power requirement depends on the transmission bandwidth.

    Classification of Mobile Communication Systems

Mobile radio communication means any radio communication between two terminals of which one or both are in motion. Mobile radio communication systems can be classified as follows:

(a)        Radio Phones (or walkie-talkies): These are two-way radios such as citizen band radios which are allocated channels for anyone to use whenever the channels are free. This system affords no privacy to the user.