Difference between AMPS and D-AMPS Cellular Systems
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.
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.|