AMPS was the first-generation analog cellular system developed in the 1970s and 1980s. It used analog FM modulation with 30 kHz channel bandwidths. AMPS was deployed across North America in the early 1980s and introduced cellular communications. However, it had limitations like low capacity and lack of privacy. Successor 2G digital standards like NAMPS and D-AMPS improved capacity but have now been replaced by newer 3G and 4G technologies.

1. AMPS

2. AMPS
A - Advanced
M - Mobile
P - Phone
S - System

3. WHAT IS AMPS?
• AMPS is known as the first generation (1G) analog
commercial cellular systems . It introduced in early
1980s.
• It is based on Analog modulation .
• It is the earliest radio standard in North America.

4. NORTH AMERICAN SYSTEMS
AMPS
NAMPS TDMA CDMA
Generation
2n
d
1st

5. INTRODUCTION
• First Generation (1G) Systems developed late 70’s
early 80’s, deployed in 80’s.
• Advanced Mobile Phone System (AMPS) – USA
• Total Access Communications Systems (TACS) - UK
• Nordic Mobile Telephone (NMT) System –
Scandinavia
• C450 - W. Germany
• NTT System - Nippon Telephone & Telegraph (NTT)

6. FIRST GENERATION SYSTEMS

7. FIRST GENERATION SYSTEMS
• First generation systems targeted to few subscribers
with car phones
• Capacity can be increased by smaller cells but:
• More difficult to place base stations at locations for
necessary radio coverage
• Increased signaling for handoffs, and more frequent
handoffs
• Base stations handle more access requests and registrations

8. AMPS FACTS
• Analog FM modulation
• RF bandwidth 30 kHz.
• Frequency allocated by FCC on 824-849 MHz for
downlink and 869-894 MHz for uplink traffic.
• Uses the same system throughout the US
• Available in U.S., Canada, Hong Kong, New Zealand,
Thailand

9. HISTORY
• Advanced Mobile Phone System is the first generation
wireless in US.
• Earlier systems used line of sight radio (e.g. AT&T’s
Improved Mobile Telephone Service in 1960s)
• AT&T developed cellular concept in 1940s
• 1971 proposed High Capacity Mobile Phone Service to
FCC
• 1979 FCC standardized it as AMPS in 800-900 MHz

10. 1983 ERE CELL PHONE

11. HISTORY OF EVOLUTION
• Motorola developed N-AMPS for low-cost evolution to
digital and increase capacity.
• Divided analog channel into 3 by FDMA, decreasing
bandwidth 30kHz per channel to 10kHz such that
2496 channels can be assigned, in stead of 832 for
the normal AMPS mode.
• Supported by new 100 b/s in-band sub-audible
signaling control channel also used for text
data (paging)

12. HISTORY OF EVOLUTION
• The uniformity of the analogue AMPS system throughout
the US highly contributed to its success of capturing 2/3 of
the analog cellular subscribers worldwide.
• In 1990, A 1900 MHz version of AMPS has been developed,
which allows dual-band/dual-mode 800/1900 MHz
systems. Seamless inter-working between 800 and 1900
MHz networks is possible through dual-band/dual-mode
mobile stations.
• Around 1995, AMPS had an estimated 13 Million

13. AMPS SYSTEM COMPONENTS
• Public Switch Telephone Network (PSTN)
• Mobile Telephone Switching Office (MTSO)
• Cell site with antenna
• Mobile Subscriber Unit (MSU)

14. AMPS ARCHITECTURE

15. AMPS CHARACTERISTICS/FEATURES
• Invented by Bells Labs and first installed in the U.S. in
1982
• Analog FDMA (Frequency Division Multiple Access)
• ISM 800-MHz band
• Base Station → Mobile Station: forward
communication channels (824-849 MHz: 25 MHz
band)
• Base Station ← Mobile Station: reverse
communication channels (869-894 MHz: 25 MHz
band)
• Voice channel – Frequency modulation (30 kHz)
• Control Channels - FSK (Frequency Shift Keying) –

16. AMPS/N-AMPS CHARACTERISTICS
AMPS N-AMPS
• Channel spacing 30 kHz 10 kHz
• Spectrum allocation 40 MHz 40 MHz
• Additional spectrum 10 MHz 10 MHz
• Total number of channels 832 2496
MHz

17. CELLULAR BANDS FOR AMPS

18. AMPS CHARACTERISTICS/FEATURES
• No of Channels
• 832 channels: 25 MHz / 30 kHz, can be shared
by two providers
• Each provider: 416 channels in each cell , 21
channels for control, 395 channels for voice
• Frequency Reuse Factor
• Each cell uses some set of frequencies not used by
any of its neighbors
• Reuse factor 7

19. FREQUENCY REUSE FACTOR OF 7
6
7
5
1
2
3
4
6
7
5
1
2
3
4
6
7
5
1
2
3
4

20. CHANNELS USED BY THE AMPS
• Forward Control Channel (FOCC) – primarily used by
the BS to page and locate the MS’s available within the
coverage area.
• Reverse Control Channel (RECC) – control for the
reverse direction is little involved as a number of MSs
communicate with the BS simultaneously.

21. CHANNELS USED BY THE AMPS
• Forward Voice Channel(FVC) - used for one-to-one
communication from the BS to each individual MS.
(tower to mobile)
• Reverse Voice Channel(RVC) - used for one-to-one
communication from MS to the BS during calls in
progress and is assigned by the MS to BS for its
exclusive use. (mobile to tower)

23. AMPS SYSTEM IDENTIFIERS
Notatio
n
Name Size
bits
Description
MIN Mobile Identifier 34 Assigned by company
to subscriber
ESN Electronic serial no. 32 Assigned by
manufacturer
SID System identifier 15 Assigned by regulators
to a geographical
service area
SCM Station class mark 4 Capability of a mobile
station
SAT Supervisory audio
tone
* Assigned by operating
company to each BST
DCC Digital color code 2 Assigned by operating

24. IDENTIFIERS USED IN AMPS SYSTEM
• Electronic Serial Number (ESN) - A 32-bit binary
number uniquely identifies a cellular unit or a MS and
is established by the manufacturer at the factory.
• System Identification Number (SID) – a unique 15-bit
binary number assigned to a cellular system, assigned
by FCC to every cellular system.
• Mobile identification Number (MIN) - A digital
representation of the MS’s 10-digit directory
telephone number.

25. IDENTIFIERS USED IN AMPS SYSTEM
• Station Class Mark (SCM) - A parameter that identifies
certain characteristics of a MS (Mobile Station). An
example being its frequency capabilities.
• Supervisory Audio Tone (SAT) – The SAT tone is used to
identify users on the same operating frequencies, but in
different cells.
• Digital Color Code (DCC) - A digital representation
equivalent of the supervisory audio tone used in the
AMPS system

26. AMPS TRANSMISSION FORMATTING

27. AMPS - INITIALIZATION

28. AMPS - MOBILE RECEIVES CALL

29. INITIAL AMPS SYSTEM OPERATORS

30. MOBILITY MANAGEMENT IN AMPS
•Initially could not roam freely
• Restricted to limited geographical regions (MSA or
RSA)
• Legal hurdles, billing problems, proprietary systems
in the backhaul
• Implementation of databases/signaling to handle
mobility was not available/standardized

31. MOBILITY MANAGEMENT IN AMPS
• Replaced by ad hoc measures
• Manual clearing house approach
• Follow-me roaming (GTE) – automated clearing
house
• User has to register when he goes to a new location

32. AMPS DISADVANTAGES
• Low calling capacity
• Limited spectrum
• No room for spectrum growth
• Poor data communications
• Minimal privacy
• Inadequate fraud protection

33. SUCCESSOR TECHNOLOGIES
NAMPS (2G)
• NAMPS is a US cellular radio system that combines
existing voice processing with digital signaling.
• NAMPS was designed to solve the problem of low
calling capacity but increases the possibility of
interference because channel bandwidth is reduced.

34. SUCCESSOR TECHNOLOGIES
• Later, many AMPS networks were partially converted to
D-AMPS, often referred to as TDMA. D-AMPS,
commercial deployed since 1993, was a digital, 2G
standard used mainly by AT&T Mobility and U.S.
Cellular in the United States, Canada, Mexico, Brazil,
Russia, Venezuela, and Israel.
• In most areas, D-AMPS is no longer offered and has
been replaced by more advanced digital wireless

36. DIGITAL CELLULAR SYSTEMS
• The advantages of digital cellular technologies over
the analog cellular networks include increased
capacity and security.
• Technology options such as TDMA and CDMA offer
more channels in the same analog cellular bandwidth
and encrypted voice and data.