Exercise 3.2: GSM Services

From LNTwww

List of GSM services

Any  "Public Land Mobile Network"  $\rm (PLMN)$  must provide the fixed network infrastructure and so-called  "interworking functions"  $\rm (IWF)$.  This is the only way to provide the desired services at the user interface.

GSM services are divided into three categories:

  • Bearer services,
  • Tele services,
  • Supplementary services.

Basis for data transmission are the  bearer services,  where the maximum data rate is  $\text{9.6 kbits/s}$.

Tele services  are end-to-end services.  The most important of these are:

  1. the telephone service,
  2. the fax service,
  3. the short message service  $\rm (SMS)$.

Various  supplementary services  belong to each phase of GSM development:

  1. "call display",  "call forwarding"  and  "caller ID"  in phase 1,
  2. "call waiting",  "hold"  and  "conference call"  in phase 2,
  3. "GPRS",  "HSCSD",  "EDGE"  in phase 2+.

Hint:  The exercise belongs to the chapter  "General Description of GSM".



Which of the GSM services are the basis for data transmission?

bearer services,
supplementary services.


What is the maximum data rate for GSM data transmission?

$2.4 \ \rm kbit/s$.
$7.8 \ \rm kbit/s$.
$9.6 \ \rm kbit/s$.


Which statements are true for teleservices?

Tele services are end-to-end services.
A distinction is made between synchronous and asynchronous tele services.
Examples are the telephone, fax and SMS services.


Which supplementary services originate from GSM phase 2?

"Call Forwarding",
"Call Waiting",
"General Packet Radio Service"  $\rm (GPRS)$,
"Conference Call"  $\rm (CONF)$.


What technology is used in  "High Speed Circuit-Switched Data"  $\rm (HSCSD)$?

Packet switching,
circuit switching.


(1)  Correct is the  proposed solution 1:

  • Bearer services form the basis for data transmission.
  • They provide the technical means to transport data in a secured manner.

(2)  Correct is the  proposed solution 3:

  • The maximum data rate for GSM data transmission is  $9.6 \rm kbit/s$.
  • There are synchronous and asynchronous as well as circuit-switched and packet-switched data transmission.

(3)  Correct are the  proposed solutions 1 and 3:

  • Proposition 2 is incorrect:
  • The terms  "synchronous"  and  "asynchronous"  play a role only in connection with bearer services.

(4)  Correct are the  proposed solutions 2 and 4:

  • In contrast,  "call forwarding"  belongs to GSM phase 1 and  "General Packet Radio Service"  $\rm (GPRS)$  to phase 2+.

(5)  Correct is the  proposed solution 2:

  • "High Speed Circuit-Switched Data"  $\rm (HSCSD)$  was introduced as a circuit-switched transmission technology.
  • In contrast,  "General Packet Radio Service"  $\rm (GPRS)$  operates as packet-switched and  "Enhanced Data Rate for GSM Evolution"  $\rm (EDGE)$  can be described as circuit-switched data service.