Exercise 3.2: GSM Services

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List of GSM services

Any  Public Land Mobile Network  (PLMN) must provide the fixed network infrastructure and so-called  Interworking Functions  (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.

The basis for data transmission is the carrier services, where the maximum data rate is $\text{9.6 kbits/s}$ .

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

• the telephone service,
• the fax service,
• the short message service  (SMS).

Various ancillary services belong to each phase of GSM development:

• call display, call forwarding and caller ID in phase 1,
• call waiting, hold  (Hold)  and conference call  (CONF)  in phase 2,
• General Packet Radio Service  (GPRS), High Speed Circuit-Switched Data  (HSCSD), Enhanced Data Rates for GSM Evolution  (EDGE) in phase 2+.

Hint:

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

Questions

1

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

	bearer services,
	teleservices,
	supplementary services.

2

What is the maximum data rate for GSM data transmission?

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

3

Which statements are true for teleservices?

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

4

Which additional services originate from GSM phase 2?

	Call forwarding,
	Call Waiting,
	General Packet Radio Service  (GPRS),
	Conference Call  (CONF).

5

What technology is used in  High Speed Circuit-Switched Data  (HSCSD)?

	Packet switching,
	circuit switching.

Solution

Solution

(1)  Correct is the proposed solution 1:

• Carrier 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 proposed solutions 1 and 3:

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

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

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

(5)  Correct is the proposed solution 2:

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