The protocols described here are from the GSM and the
CDMA protocol families and most are common to both protocol
For more protocols related to cellular protocols see
the following families:
for a description of SS7 protocols.
information on cellular and telecom protocol testing
described here include:
||Base Station Management Application Part
||BSS Application Part
||BSS Managment Application Part
||Base Transceiver Station Management
||Direct Transfer Application Part for CDMA
||Direct Transfer Application Part for GSM
||Mobile Internet Protocol
||Short Message Service
||Short Message Transfer Layer Protocol
In 1989, GSM responsibility
was transferred to the European Telecommunication Standards
Institute (ETSI), and phase I of the GSM specifications were
published in 1990. Commercial service was started in mid1991,
and by 1993 there were 36 GSM networks in 22 countries, with
25 additional countries having already selected or considering
GSM In addition to Europe, South Africa, Australia, and many
Middle and Far East countries have chosen to adopt GSM. By the
beginning of 1994, there were 1.3 million subscribers worldwide.
The acronym GSM now (aptly) stands for Global System for Mobile
From the beginning, the planners of GSM wanted
ISDN compatibility in services offered and control signaling
used. The radio link imposed some limitations, however, since
the standard ISDN bit rate of 64 Kbps could not be practically
The digital nature of GSM allows data, both
synchronous and asynchronous data, to be transported as a bearer
service to or from an ISDN terminal. The data rates supported
by GSM are 300 bps, 600 bps, 1200 bps, 2400 bps, and 9600 bps.
The most basic teleservice supported by GSM
is telephony. A unique feature of GSM compared to older analog
systems is the Short Message Service (SMS). Supplementary services
are provided on top of teleservices or bearer services, and
include features such as international roaming, caller identification,
call forwarding, call waiting, multiparty conversations,
and barring of outgoing (international) calls, among others.
Code Division Multiple
Access (CDMA) is a digital air interface standard, claiming
eight to fifteen times the capacity of traditional analog cellular
systems. It employs a commercial adaptation of a military spread-spectrum
technology. Based on spread spectrum theory, it gives essentially
the same services and qualities as wireline service. The primary
difference is that access to the local exchange carrier (LEC)
is provided via a wireless phone.
Though CDMAs application in cellular
telephony is relatively new, it is not a new technology. CDMA
has been used in many military applications, such as:
- Anti-jamming (because of the spread signal,
it is difficult to jam or interfere with a CDMA signal).
- Ranging (measuring the distance of the
transmission to know when it will be received).
- Secure communications (the spread spectrum
signal is very hard to detect).
CDMA is a spread spectrum technology, which
means that it spreads the information contained in a particular
signal of interest over a much greater bandwidth than the original
signal. With CDMA, unique digital codes, rather than separate
RF frequencies or channels, are used to differentiate subscribers.
The codes are shared by both the mobile station (cellular phone)
and the base station, and are called pseudo-random code sequences.
Since each user is separated by a unique code, all users can
share the same frequency band (range of radio spectrum). This
gives many unique advantages to the CDMA technique over other
RF techniques in cellular communication.
CDMA is a digital multiple access technique
and this cellular aspect of the protocol is specified by the
Telecommunications Industry Association (TIA) as IS-95. In CDMA,
the BSSAP is divided into the DTAP and BSMAP (which corresponds
to BSSMAP in GSM).
Cellular Family Protocol
BSMAP | BSSAP
| BSSMAP | BSSAPLE | BSSLAP | BTSM
| CC | DTAP
(CDMA) | DTAP (GSM)
| MM | Mobile
IP | RR | SMS