The evolution of mobile communications technologies

In a competitive market such as mobile telecommunications is very important to predict which technologies will become leaders in the field. In fact, the steady increase of users leads to a proposal for continued technology improvements beyond those already present.

In recent years the development of color screens small but good quality, lower costs of memory and an increase in computational power have made possible the emergence of new mobile devices with high performance. If you add to this an increasing level of awareness among users about the possibilities offered by technology, we understand that the number of available services is continuously increasing, with particular reference to Internet services.

The success of the Internet and services based on IP benefit enormously from the integration with mobile devices, providing a catchment area and in general a much broader spectrum of use. Due to user mobility can also be born different services, specifically dedicated to mobile computing devices such as smartphones, including those based on additional information provided by its own IP, such as geolocalizzazzione.

Before proceeding to an analysis of current communication technologies, which allow the use of such services, throwing a look to the future, it is useful to provide a brief overview of the structure of the first digital mobile communication network, closer in some respects that of a fixed telephone network to the Internet of a network: the technology we're talking about GSM .

GSM

In 1982, the CEPT (Conférence Européenne des Administrations des Postes et des Télécommunications) created a special group for the definition of a pan-European cellular network, the Groupe Speciale Mobile (Group Speciale Mobile, GSM). In 1985 the first list was drawn up standards, and in 1987 was signed the first Memorandum of Understanding: the agreement allowed him to coordinate the development of GSM networks and plan the introduction of services, as well as to coordinate the 'routing and charging .

In 1992, the GSM standard was made ​​official and took on the meaning of the acronym for Global System for Mobile communications (Global System for Mobile Communications), while in 1994 it was introduced the ability to send and receive SMS messages.

GSM is a digital system with multiple access TDMA / FDMA with 8 time slots per carrier bearing and distance between the 200 kHz. The modulation is GMSK and frequency hopping is optional (but almost always used). There is also a power control that is executed on the basis of the estimated distance and signal quality, not only for energy savings, but also to reduce the emission of electromagnetic radiation.

The technique for obtaining a full duplex Frequency Division Duplex (FDD) . This means that different frequencies are used for up-link and down-link. The channel up-link and down-link is 45 MHz (in GSM900) and 95 MHz (GSM1800 networks).

What is important to understand is how to identify the GSM network, basically, a network of circuit-switched communications. It is understood that that at the time of the call, the user request to establish a connection to the first node of the network, that is, in general, the local antenna. This request follows a setup phase in which it is located within the GSM network, a path that connects the sender and the recipient, maintaining the fixed connection and exclusive for the duration of the communication.

This type of connection ensures the delivery of data and sending in the order delay set, and is therefore well suited for voice traffic. We note, however, that use this type of network architecture for the exchange of data (for example, for the use of the services mentioned above) would be rather counterproductive, since the flow of information is not necessarily continuous, but the network is busy (ie circuit remains active) even in times when there has been no transmission of data. The circuit is in fact only released once the communication is completed in its entirety.

GPRS

With the technology GPRS , the mobile communication network starts orinetarsi to packet-switched architecture, or more like that of a network that the Internet is structured with a traditional telephone network.

Fact GPRS (also known as 2.5G, why inserted between GSM, 2G, and UMTS , 3G) makes communication based on data packets. These packets are sent to the network, as it shall send to the addressee in accordance with their policies.

You do not have a virtual circuit between sender and receiver, which allows for a less constrained communication management and overall more efficient, but at the expense of a loss of quality of service when considering a single call.

The communication protocol is in fact best effort type and does not guarantee either the correct reception of the packet that may need to be resent. Although not suitable for voice, GPRS is a step forward in the creation of mobile data exchange, since it avoids the network is occupied even when idle and in general overloading of virtual ciruiti, reliable but expensive. The next step is represented by UMTS.

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