Posted inMobile Computing
ROUTING
A satellite system together with gateways and fixed terrestrial networks as shown in Figure 5.1 has to route data transmissions from one user to another as any other network does.…
Posted inMobile Computing
FREQUENCY ALLOCATION
Radio transmission can take place using many different frequency bands. Each frequency band exhibits certain advantages and disadvantages. Figure gives a rough overview of the frequency spectrum that can be…
Posted inMobile Computing
CONNECTION ESTABLISHMENT
The number dialed to reach a mobile subscriber (MSISDN) contains no information at all about the current location of the subscriber. In order to establish a complete connection to a…
Posted inMobile Computing
GSM – Protocol Stack
GSM architecture is a layered model that is designed to allow communications between two different systems. The lower layers assure the services of the upper-layer protocols. Each layer passes suitable…
Posted inInternet Programming
GSM – Architecture
A GSM network comprises of many functional units. These functions and interfaces are explained in this chapter. The GSM network can be broadly divided into: · The Mobile Station (MS) · The…
Posted inMobile Computing
What is GSM?
If you are in Europe or Asia and using a mobile phone, then most probably you are using GSM technology in your mobile phone. · GSM stands for Global System for Mobile Communication. It…
Posted inMobile Computing
Spread Spectrum Multiple Access
Spread spectrum multiple access (SSMA) uses signals which have a transmission bandwidth whose magnitude is greater than the minimum required RF bandwidth. There are two main types of spread spectrum…
Posted inMobile Computing
Frequency Division Multiple Access (FDMA)
FDMA is the basic technology for advanced mobile phone services. The features of FDMA are as follows. FDMA allots a different sub-band of frequency to each different user to access…
Posted inMobile Computing
Time Division Multiple Access (TDMA)
In the cases where continuous transmission is not required, there TDMA is used instead of FDMA. The features of TDMA include the following. TDMA shares a single carrier frequency with…
Posted inMobile Computing
Code Division Multiple Access (CDMA)
Code division multiple access technique is an example of multiple access where several transmitters use a single channel to send information simultaneously. Its features are as follows. In CDMA every…