Overview of Mobile Radio Systems in North America

This page provides an overview of various mobile radio systems used in North America, including AMPS, NAMPS, USDC, CDPD, IS-95, GSC, POCSAG, FLEX, DCS-1900 (GSM), PACS, MIRS, and iDEN.

Mobile Radio System Overview

The following table summarizes the key characteristics of these systems:

TYPE	YEAR	MULTIPLE ACCESS	FREQUENCY BAND	MODULATION	BW
AMPS	1983	FDMA	824-894 MHz	FM	30 kHz
NAMPS	1992	FDMA	824-894 MHz	FM	10 kHz
USDC	1991	TDMA	824-894 MHz	Pi/4 DQPSK	30 kHz
CDPD	1993	FH/ Packet	824-894 MHz	GMSK	30 KHz
IS-95	1993	CDMA	824-894 MHz/ 1.8-2.0 GHz	QPSK /BPSK	1.25 MHz
GSC	1970s	Simplex	Many	FSK	12.5 KHz
POCSAG	1970s	Simplex	Many	FSK	12.5 KHz
FLEX	1993	Simplex	Many	4-FSK	15 KHz
DCS-1900 (GSM)	1994	TDMA	1.85-1.99 GHz	GMSK	200 KHz
PACS	1994	TDMA/ FDMA	1.85 -1.99 GHz	Pi/4 DQPSK	300 KHz
MIRS	1994	TDMA	Many	16QAM	25 KHz
iDen	1995	TDMA	Many	16QAM	25 KHz

Explanation of Terms:

• TYPE: The name of the mobile radio system. This could be a cellular standard, a paging system, or a specialized mobile radio (SMR) system.
• YEAR: The year the system was introduced or became commercially available.
• MULTIPLE ACCESS: The method used to allow multiple users to share the same frequency band (FDMA, TDMA, CDMA).
• FREQUENCY BAND: The range of radio frequencies used by the system.
• MODULATION: The type of modulation used to encode information onto the radio signal (FM, GMSK, QPSK, etc.).
• BW: The bandwidth or channel width occupied by a single communication channel.