Analýza frekvenčního klíčování při přenosu krátkých textových zpráv v pevné telefonní síti

Abstract

SMS is a communication service that allow the exchange of short text messages between terminals belongs to different types of networks. Service of sending SMS, after successful using in mobile networks, was get in to service in fixed networks as well. In this network the two possibilities of delivery exist, first one is data form of delivery and the second one is speech delivery. The work is in their theoretical part focused on analysis of FSK modulation and on description of SMS dates structure according to ETSI recommendations. Analytical part of work was focused on clearing of SMS coding. Almost all messages from different layers of protocols are expressed by hexadecimal numbers, but some of them are expressed by binary numbers. Detailed explanation of meaning of particular messages parameters in obtained data is important for understanding to data exchange between SMS centre and terminal during the SMS messages transfer on fixed line.