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GSM vs UMTS

This page on GSM vs UMTS describes difference between GSM and UMTS. Both are cellular wireless technologies developed for mobile communications. GSM works on FTDMA principle while UMTS works on CDMA principle.

Initially GSM was developed to take care of voice communications. Later with advent of GPRS/EDGE, data communications have become more popular with this wireless standard. In GSM, one frequency as well as one time slot is dedicated for communication in each direction by the GSM mobile. Hence the name frequency/time division multiple access. It is also referred as FDMA/TDD based system.

In CDMA pseudo random codes (i.e. PN codes) in the form of walsh codes are assigned for communication. These are referred as spreading codes.


Key difference between GSM and UMTS systems

GSM stands for Global system for mobile evolution, developed based on 3GPP standards. GSM network is consists of Mobile station, Base station subsystem(BTS, BSC) and Network(MSC) and operation subsystem. In GSM,data is supported based on GPRS technology.

UMTS stands for Universal Mobile Telecommunications System, developed based on 3GPP standards. UMTS network composed of three main parts UE (User Equipment),Radio Access Network (RAN) and Core Network.Various technologies fall under UMTS based on different releases from 3GPP community. UMTS is also referred as 3G. WCDMA was introduced in R99. Later HSDPA,HSUPA,HSPA,LTE and LTE advanced were introduced consecutive releases from 3GPP. Though UMTS supports both voice and data similar to GSM,certain standards for example HSPA was targetted mainly for increasing the data rate capabilities of UMTS mobile terminals/dongles.

In GSM Base station is referred as BTS and in UMTS it is referred as NodeB. In GSM Mobile subscriber is referred as ME and in UMTS it is referred as UE.

Frame structure,logical channels and frequency bands are different in both the technologies and are explained in following tutorials.

Following table summarizes difference between GSM and UMTS standard based technologies.


Features GSM UMTS
Frequency
Band(MHz)
There are various bands in GSM, the major among them are 850MHz, 900MHz, 1800MHz and 1900MHz, Refer GSM ARFCN to Frequency Conversion➤ There are various bands in UMTS from Band-I to Band-VI, Each band specifies frequency and UARFCN, Refer UMTS UARFCN to Frequency conversion➤
Carrier
Spacing(KHz)
200 KHz 1230 KHz (CDMA version)
Channel
Types
In GSM, channels are divided into traffic channel and control channel based on functionality of use in the system, Refer GSM channels➤ In UMTS, channels are divided into logical, transport and physical based on where tehy are used along with their functions, Refer UMTS channels➤
Multiple
Access
technique
FDMA/TDMA CDMA
Frame Frame duration is about 4.615ms, GSM Frame➤ Frame duration is about 10ms (consisting of 15 slots), UMTS Frame➤
Network Architecture Refer GSM Architecture➤. Refer UMTS Architecture➤.
Channel
rate (Kb/s)
270.833 Kbps 1228.8 kbps (in CDMA)
Modulation
Efficiency
in b/s/Hz
1.35 b/s/Hz 1.0 b/s/Hz (CDMA)
Standard
versions
There are various releases such as R99(WCDMA), R5 (HSDPA), R6(HSUPA) etc. Refer UMTS releases➤. There are various documents specified by ETSI and 3GPP, 3GPPTS 45-series

GSM and UMTS RELATED LINKS

GSM tutorial covering GSM basics,GSM network architecture, network elements,GSM system specifications,GSM frame structure, GSM physical layer or speech processing and network entry,
Refer basic GSM tutorial.

UMTS tutorial covering UMTS Releases,UMTS frequency bands,UARFCN, UMTS multiple access,UMTS frame structure and UMTS network architecture,
Refer basic UMTS tutorial.

What is Difference between

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Difference between SC-FDMA and OFDM
Difference between SISO and MIMO
Difference between TDD and FDD
Difference between 802.11 standards viz.11-a,11-b,11-g and 11-n
OFDM vs OFDMA
CDMA vs GSM
Bluetooth vs zigbee
Fixed wimax vs mobile
wibro vs mobile wimax

RF and Wireless Terminologies


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