Difference between AMPS and D-AMPS Cellular Systems
AMPS
The first generation (1G) of cellular mobile communication systems, called the Advanced Mobile Phone System. In Advanced Mobile Phone System (AMPS), each mobile phone uses a 32-bit serial number and a 10 digit (34-bit) phone number in its PROM. Out of the 10 digits in telephone number, 3 digits (10 bits) are used for area code and 7 digits (24 bits) are used for Subscriber Number.
When a phone is switched on, it scans a pre-programmed list of 21 control channels to find the most powerful signal. The phone then digitally broadcasts its 32-bit serial number and 34-bit phone number along with error detection codes. Though the voice channels are analogue and the control signals are digital.
D-AMPS
Digital Advanced Mobile Phone System (D-AMPS) is the second generation of AMPS and fully uses digital signals with backward compatibility with AMPS. It uses 30 kHz channels and channels can be a mix-up of analogue and digital systems. The MSC can determine which channel is analogue and which channel is digital. It can also change the channel type from analogue to digital and vice-versa. The MSC manages the handoff completely.
AMPS vs D-AMPS
| 1. It stands for Advanced Mobile Phone System | 1. It stands for Digital Advanced Mobile Phone System |
| 2. AMPS was used for the first generation (1G) of mobile networks. | 2. D-AMPS was used for the second generation (2G) of mobile networks. |
| 3. AMPS uses Frequency Division Multiple Access (FDMA) for connecting mobile phones to the mobile networks. | 3. D-AMPS uses a combination of Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) for connecting mobile phones to the mobile networks. |
| 4. AMPS provides less signal clarity than D-AMPS | 4. D-AMPS provides greater signal clarity than AMPS |
| 5. AMPS provides less security than D-AMPS. | 5. D-AMPS provides better security than AMPS. |