# Exercise 3.6Z: Concepts of 3G Mobile Communications Systems

Terms of the 3G mobile radio systems (except one entry )

On the right there are various terms used in 3G mobile communications systems.

Third generation systems include, for example, the following standards:

• $\text{IMT–2000}$:   This abbreviation stands for $\rm I\hspace{-0.01cm}$nternational $\hspace{0.05cm}\rm M\hspace{-0.01cm}$obile $\hspace{0.05cm}\rm T\hspace{-0.01cm}$elecommunications at the year $2000$;
• $\text{UMTS}$:   $\rm U\hspace{-0.01cm}$niversal $\rm M\hspace{-0.01cm}$obile $\rm T\hspace{-0.03cm}$elecommunication $\rm S\hspace{-0.01cm}$ystem.

Only one of the twenty listed terms is out of the ordinary.  This is a system extension of  $\rm GSM$.

Notes:

• This task refers to the chapter Characteristics of UMTS.
• Reference is also made to the main chapter  UMTS   of the book "Examples of Communication Systems".

### Questionnaire

1

Which of the following statements are correct?

 IMT-2000 is a subset of UMTS. UMTS is a subset of IMT-2000.

2

Which statements do the color assignments in the graphic allow?

 Red entries describe system variants of UMTS. Green entries describe system variants of UMTS. Blue entries describe system variants of UMTS.

3

Continue to look at the color assignment in the graphic. What is valid?

 Red entries belong to IMT-2000, not to UMTS. Green entries belong to IMT-2000, not to UMTS.

4

Which base units secure the transport layer in UMTS?

 The "Core Network"  (CN), the "Gateway Mobile Switching Center"   (GMSC), the "Mobile Switching Center"   (MSC), the "Base Station"   (for UMTS:   "Node B"), the "Radio Network Controller"   (RNC), the "UMTS Terrestrial Radio Access Network"   (UTRAN).

5

Which facilities handle data switching for UMTS?

 The "Core Network"  (CN), the "Gateway Mobile Switching Center"   (GMSC), the "Mobile Switching Center"   (MSC), the "Base Station"   (for UMTS:   "Node B"), the "Radio Network Controller"   (RNC), the "UMTS Terrestrial Radio Access Network"   (UTRAN).

### Solution

#### Solution

(1)  Correct is the solution 2:

• The IMT-2000 standard includes in a first level "W-CDMA",  "TD-CDMA",  "TDMA"  and "FD-TDMA",
where only the first two mentioned variants are simultaneously attributed to the UMTS standard.
• From this follows:   UMTS is a subset of IMT-2000, not vice versa.

(2)  All entries belonging to UMTS are marked in red in the table   ⇒   Answer 1:

• $\rm W-CDMA$  includes
1.   "UTRA-FDD", the FDD component of the European UMTS standard,
2.   the American "cdma 2000 system", which, however, does not belong to UMTS.
• Added to  $\rm TD-CDMA$  are:
1.   "UTRA-TDD", the TDD component of UMTS,
2.   the Chinese "TD-SCDMA", now integrated into the UMTS-TDD standard.

(3)  Correct is the solution 2:

The three system variants that belong to IMT-2000 but not to UMTS are:

• $\rm TDMA$:   This includes further developments of the GSM offshoot "EDGE" and its American counterpart "UWC-136",
• $\rm FD-TDMA$,   the further development of the cordless telephony standard "DECT"',
• the American standard  $\rm cdma$.

(4)  Correct are answers 1, 4 and 6, as you can read in the book "Examples of Communication Systems" in chapter  UMTS Network Architecture.

(5)  From the above link it also appears that answers 2, 3 and 5 apply here.

By the way:
The only term in the graphic on the information page that does not refer to UMTS is "GPRS"   ⇒  "General Packet Radio Service" is a GSM extension.