Description

GSM/GPRS/3G/4G

GSM technology :

The GSM system was designed as a second generation (2G) cellular phone technology. One of the basic aims was to provide a system that would enable greater capacity to be achieved than the previous first generation analogue systems. GSM achieved this by using a digital TDMA (time division multiple access approach). By adopting this technique more users could be accommodated within the available bandwidth. In addition to this, ciphering of the digitally encoded speech was adopted to retain privacy. Using the earlier analogue cellular technologies it was possible for anyone with a scanner receiver to listen to calls and a number of famous personalities had been "eavesdropped" with embarrassing consequences.

GSM basics:

The GSM cellular technology had a number of design aims when the development started:

• It should offer good subjective speech quality
• It should have a low phone or terminal cost
• Terminals should be able to be handheld
• The system should support international roaming
• It should offer good spectral efficiency
• The system should offer ISDN compatibility

GSM Network Architecture:

The GSM network architecture as defined in the GSM specifications can be grouped into four main areas:

• Mobile station (MS)
• Base-Station Subsystem (BSS)
• Network and Switching Subsystem (NSS)
• Operation and Support Subsystem (OSS)

The different elements of the GSM network operate together and the user is not aware of the different entities within the system.

GPRS:

GSM was the most successful second generation cellular technology, but the need for higher data rates spawned new developments to enable data to be transferred at much higher rates.

The first system to make an impact on the market was GPRS. The letters GPRS stand for General Packet Radio System, GPRS technology enabled much higher data rates to be conveyed over a cellular network when compared to GSM that was voice centric.

GPRS technology became the first stepping-stone on the path between the second-generation GSM cellular technology and the 3G W-CDMA / UMTS system. With GPRS technology offering data services with data rates up to a maximum of 172 kbps, facilities such as web browsing and other services requiring data transfer became possible. Although some data could be transferred using GSM, the rate was too slow for real data applications.

GPRS benefits

GPRS technology brings a number of benefits for users and network operators alike over the basic GSM system. It was widely deployed to provide a realistic data capability via cellular telecommunications technology.

GPRS technology offered some significant benefits when it was launched:

• Speed:   One of the headline benefits of GPRS technology is that it offers a much higher data rate than was possible with GSM. Rates up to 172 kbps are possible, although the maximum data rates realistically achievable under most conditions will be in the range 15 - 40 kbps.
• Packet switched operation:   Unlike GSM which was used circuit switched techniques, GPRS technology uses packet switching in line with the Internet. This makes far more efficient use of the available capacity, and it allows greater commonality with Internet techniques.
• Always on connectivity:   A further advantage of GPRS is that it offers an "Always On" capability. When using circuit switched techniques, charges are based on the time a circuit is used, i.e. how long the call is. For packet switched technology charges are for the amount of data carried as this is what uses the services provider's capacity. Accordingly, always on connectivity is possible.
• More applications:   The packet switched technology including the always on connectivity combined with the higher data rates opens up many more possibilities for new applications. One of the chief growth areas that arose from GPRS was the Blackberry form of mobile or PDA. This provided for remote email applications along with web browsing, etc.
• CAPEX and OPEX:   The Capital expenditure (CAPEX) and operational expenditure (OPEX) are two major concerns for operators. As GPRS was an upgrade to existing GSM networks (often implemented as a software upgrade achieved remotely), the capital expenditure for introducing GPRS technology was not as high as deploying a complete new network. Additionally OPEX was not greatly affected as the basic base-station infrastructure remained basically the same. It was mainly new core network elements that were required. 

What is 3G Technology?

3G is the next generation of technology which has revolutionized the telecommunication industry. Apart from increasing the speed of communication, the objective of this technology is to provide various value added services like  video calling, live streaming, mobile internet access, IPTV, etc on the mobile phones. These services are possible because the 3G spectrum provides the necessary bandwidth.

Technically speaking 3G is a network protocol which refers to the generations of mobile phones and telecommunication equipments which are compatible with the International Mobile Telecommunications-2000 (IMT-2000) standards stated by International Telecommunication Union (ITU). The basic requirement for compiling to IMT-2000 standards is that the technology should provide peak data rates of atleast 200 kbit/s. It’s worth mentioning that speed isn’t the only criteria for deciding whether the network protocol is 3G or not. 3G isn’t just any high speed network but a protocol which has its own standards defined under IMT-2000 by ITU.

3G Technology is designed for multimedia communication. It provides services like higher data transfer rates. One of its key visions is to provide seamless global roaming, enabling users to move across borders while using the same number and handset. According to ITU it is expected that IMT-2000 will provide higher transmission rates: a minimum speed of 2Mbit/s for stationary or walking users, and 348kbit/s in a moving vehicle. 

4G Techhnology

4G technology is meant to provide what is known as “ultra-broadband” access for mobile devices, and the International Telecommunications Union-Radio communications sector (ITU-R) created a set of standards that networks must meet in order to be considered 4G, known as the International Mobile Telecommunications Advanced (IMT-Advanced) specification.

What are the 4G Standards?

First, 4G networks must be based on an all Internet protocol (IP) packet switching instead of circuit-switched technology, and use OFMDA multi-carrier transmission methods or other frequency-domain equalization (FDE) methods instead of current spread spectrum radio technology. In addition, peak data rates for 4G networks must be close to 100 megabit per second for a user on a highly mobile network and 1 gigabit per second for a user with local wireless access or a nomadic connection. True 4G must also be able to offer smooth handovers across differing networks without data loss and provide high quality of service for next-gen media.

One of the most important aspects of 4G technology is the elimination of parallel circuit-switched and packet-switched network nodes using Internet Protocol version 6 (IPv6). The currently used standard, IPv4, has a finite limitation on the number of IP addresses that can be assigned to devices, meaning duplicate addresses must be created and reused using network address translation (NAT), a solution that only masks the problem instead of definitively solving it. IPv6 provides a much larger number of available addresses, and will be instrumental in providing a streamlined experience for users.