What is the difference between of the following mobile communication system (2G, 2.5G, 3G, 3.9G, 4G and 4G LTE) generation ?

The difference between the technologies you cited lies at different levels:

·         The first level is at the service each technology offers: the2G is basically a voice oriented technology and it is enhanced to the2.5G to offer some data service but remaining with very low throughputs in the range of473.6 kbps at maximum. The3G is both voice and data oriented with some enhancement of the offered throughput reaching384 Kbps with the UMTS variant and672 Mbps/168Mbps  (DL/UL) with the HSPA+ variant . Finally, the4G is basically a data oriented technology offering high throughputs reaching1 Gbps.

·         The second level of difference is at architectural side, seeing that each technology is based on a different network architecture

·         The third level of difference is at access mode: the2G is based on TDMA, the3G is based on WCDMA while the4G is based on OFDMA.

 

This is at a coarse level the main difference between the technologies you cited. Note that there are also other differences but that need to enter deeply into details 

2G HAVING 16Kbps SPEED ,2.5G HAVING UPTO 64 Kbps SPEED,3G HAVING 2 Mbps SPEED,3.9G HAVING MORE THAN 2Mbps SPEED,4G HAVING 1 GBPS SPEED ,4G LTE HAVING MORE THAN 1 GBPS SPEED WITH MUCH MORE BETTER QUALITY SERVICES.

2G USES DIGITAL CIRCUIT TECHOLOGY WHILE 2.5 G USES GPRS ,EDGE ,CDMA TECHNOLOGY.

3G USES WCDMA TECHNOLOGY,3.9 G USES WCDMA WIFI TECHNOLOGY,

4G USES WIMAX TECHNOLOGY ,4G LTE USES LTE WIFI TECHNOLOGY

Generation     Access Technique    Data rate    carrier BW

2G(GSM)              FDMA/TDMA         9.6 kbps       khz

2.5G(GPRS)          FDMA/TDMA         kbps      khz

2.G(EDGE)        FDMA/TDMA         kbps      khz

3G(UMTS)           WCDMA                 kbps      5 Mhz

3.5(HSDA)           WCDMA               .4           5 Mhz

3.(HSUPA)        WCDMA          UL:5.8 Mbps       5 Mhz

3.8G(HSPA+)       WCDMA           DL:.2 Mbps    5 Mhz

3.9(LTE)            OFDMA& SC-FDMA   Mbps      Mhz

4G(LTE-A)          OFDMA&SC-FDMA     1 Gbps      Mhz

 

A G is a generation.

Within each of those generations there are various competingh standards, and various "half step" improvements.

Each of these is a different modulation scheme, a different protocol stack, different technology architecture, different radio. As a result each one is a complete new network & new modem although, of course, in practise those are combined into one multi-mode physical system.

There is also a lot of marketing spin.

• 1G = analogExamples include NMT, AMPS, TACS, etcThis did not do data.
• 2G = digital, voiceExamples include GSM, D-AMPS, PDCThose could do data but only as analog modem (using the whole channel) at 9.6Kbps2.5G added dedicated digital data (GPRS)2.75G faster data (EDGE)Data rates from 9.6Kbps (GSM) to to 33Kbps (GPRS) 200Kbps or higher(2.75G)
• 3G = digital, supported data, but still circuit switchedUMTS / WCDMA, EvDOIncludes data but still onto circuit switched architecture3.5G faster data, added true always-on / packet data (HSPA)Data rates of 2Mbps-tens of MbpsNB The USA and few other places had a rival technology ("CDMA"). IS95, EvDO. That was marketed as 3G when it was launched, but initially was probably closer to 2.5G and then upgraded to 3G with the EvDO upgraded.
• 4G = wireless broadband OFDMA, flat architecture, true packet switchedPure data: voice as VoIP (VoLTE)Most people say this is LTE & WiMAX, (though some people are waiting for an upgrade to LTE-A, based on a rather silly data rate definition). 4.5G term not widely used but some people say that is LTE-AData rates of Tens of Mbps - Hundreds of Mbps
• 5G = not yet definedMuch faster. Likely to be real ~2020Being argued about now in standards bodies.Will likely be an extension of 4G but with higher data rates & better support for IoTData rates of “1Gbps” are proposed

la prochaine evolution de LTE sera un reseau mobile de 4 eme generation (4G) faisant partie des technologie reseau retenues pour entrer dans l'ensemble IMT-ADVANCED.

2G provide voiceservice, while 2.5G providevoice along with limitied data service. 3G provide both services along with increased data rate of data service. 4G is datat oriented & has increased the data speedwhile in all generations, modulation scheme has been changed while infrastructe has also been changed as generation changes. 

Project Engineer is responsible from concept design/engineering till final commissioning & handover of project but site engineer is responsible primarily for site activities looking at site with the collaboration of contractors to mobilize manpower for construction, site inspection, supervision & to monitor work progress & report their manager, who may be sitting in head office or at site. We can say, A project engineer may be handling role of site engineer as well depending upon organization structure but site engineer role is limited & it is for construction & supervision only.

2G  were based on narrow band digital networks. Signals were transmitted in the digital format and this improved the quality of calls and also reduced the complexity of data transmission

3rd generation of mobile networks has become popular largely thanks to the ability of users to access the Internet over devices like mobiles and tablets. The speed of data transmission on a 3G network ranges between 384KBPS to 2MBPS. This means a 3G network actually allows for more data transmission and therefore the network enables voice and video calling, file transmission, internet surfing, online TV, view high definition videos .

4th Generation mobile networks are believed to provide many value added features. In addition to all the 3G facilities, data transmission is believed to go through the roof with speeds ranging between 100MBPs to 1GBPS. Phew! Happy talking, surfing, conferencing, chatting, networking, partying, or whatever you want to do on your mobile phone.

 

 

the difference is that the new technology now is more aqurate and fast service to all users and subriber due to we are using a fiber optics or gpon facility .

2G is 2nd generation mobile communication (Commonly known as GSM) where we can use for either voice call or Slow Data transfer at a time. Data rate is about 9.6 Kbps. Later 2.5G is introduced with a data rate of about 171 Kbps (Practically 115 Kbps). Later 2.75G ie, EDGE has been introduced with 384 Kbps data rate.

3G is commonly known as UMTS network, speed can available upto 2Mbps. 3G network can be simultaneously used for Voice call as well as Data transfer. Later 3.5G (HSPA) has been introduced with a maximum data rate of 10Mbps (Average 1-3Mbps can be availed)

LTE (Long Term Evolution) is 3GPP release 8 with a data transfer rate of 100Mbps. whereas 3GPP release 10 ie, Advanced LTE is known as 4G network, having a speed upto 1Gbps.

 

4g is the best service for our internet speed i m also using this 4g internet speed