30-07-2012, 04:23 PM
Mobile Networking
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What is mobile networking?
Mobile networking refers to technology that can support voice and/or data network connectivity
using wireless, via a radio transmission solution. The most familiar application of mobile networking
is the mobile phone. In the past, wireless communications predominantly used circuit switching to
carry voice over a network; however, more recently both voice and data are being transmitted over
both circuit-switched and packet-switched networks.
The radio spectrum allocated to mobile networks has expanded over time. Below is a summary of
the generations of mobile networking.
Second Generation (2G)
1991 – GSM launch
The second generation of mobile systems was based on digital transmission with a number of
different standards (GSM, ERMES, CT2, CT3, DCS 1800, DECT). GSM (Global System for Mobile)
communications is the most popular standard in use today, using 900MHz and 1800MHz frequency
bands. GSM mobile systems developed digital transmission using SIM (Subscriber Identity Module)
technology to authenticate a user for identification and billing purposes, and to encrypt the data
to prevent eavesdropping. The transmission uses TDMA (Time Division Multiple Access) and
CDMAOne (Code Division Multiple Access One) techniques to increase the amount of information
transported on the network. Mobility is supported at layer 2, which prohibits seamless roaming
across heterogeneous access networks and routing domains. This means each operator must cover
the whole area or have agreements in place to permit roaming.
Fourth Generation (4G)
2007+?
4G is still at the research stage. It is based on an ad hoc networking model where there is no need for
a fixed infrastructure operation. Ad hoc networking requires global mobility features (e.g. Mobile IP) and
connectivity to a global IPv6 network to support an IP address for every mobile device. Seamless roaming
in heterogeneous IP networks (e.g. 802.11 WLAN, GPRS and UMTS) will be possible with higher data
rates, from 2Mbit/s to 10–100Mbit/s, offering reduced delays and new services. As mobile devices will not
rely on a fixed infrastructure, they will require enhanced intelligence to self configure in ad hoc networks
and have routing capabilities to route over a packet-switched network.