Introduction
Overview of technologies

For completeness and integrity of our initial review, it would be certainly more appropriated to introduce a comprehensive analysis of wireless technologies that are closely related to the topic presented in this module.

The first category of radio communication technologies can include analogue and digital cordless systems that complement, and in some cases completely replace, traditional telephones. This category undoubtedly includes CT (Cordless Telephone) system in versions CT0, CT1, CT2 and DECT (Digital European Cordless Telephone) system. The purpose of the above mentioned systems is to replace fixed wired subscriber line and enable the mobility within a limited area to the users. It is, therefore, in principle the most typical narrowband access system for the implementation of fixed wireless telephone network subscriber denoted as WLL (Wireless Local Loop).

The second category is represented by both analogue and digital cellular (further in the module referred to simply as cellular) systems forming the infrastructure of distinctive mobile radio networks. As an example, the 1st generation systems (that are analogue) are denoted as NMT (Nordic Mobile Telephone). These were followed by systems of the 2nd generation (digital) like GSM (Global System for Mobile Communication), afterwards by systems of the 3rd generation known as UMTS (Universal Mobile Telecommunication System), and finally, by the systems of the 4th generation such as LTE-A (Long Term Evolution-Advance). These technologies will be described in detail in the following chapters.

As the third category, we can integrate wireless technology used to meet the requirements and needs of participants in the personal, local, metropolitan and wide networks by means of PAN (Personal Area Network), LAN (Local Area Network), MAN (Metropolitan Area Network) and WAN (Wide Area Network). These include standard IrDA (Infrared Data Association) in versions 1.0 and 1.1, then currently a dynamically developing Bluetooth ™ technology. To complete the survey we have to also indicate the WLAN (Wireless Local Area Network) technology based on 802.11x standard and HIPERLAN (High Performance Local Area Network), which is a European alternative for IEEE 802.11.

The fourth category can be combined with technologies that provide so-called paging. The term represents one-way radio systems providing radio contact services. The radio paging systems include European ERMES (European Radio Message System) or RDS (Radio Data System) global system.

The last and the fifth, but in its own way a little specific category of radio systems, are satellite communications. It is not an access system in the strict sense because its coverage includes a substantial portion of the earth's surface and next to intercontinental connections are of particular importance for marine and aviation coverage and inaccessible, sparsely populated areas. As a representative of this category can be mentioned analogue and digital systems such is INMARSAT (International Mobile Satellite Organization), Iridium or Globalstar.

The satellite positioning systems are a complementary category in our overview. This includes, in particular, the American GPS (Global Positioning System) system, the emerging European system named as Galileo and the Russian system known GLONASS. All these systems are abbreviated as GNSS (Global Navigation Satellite System). Categorized list of all technologies used for mobile communication is presented in Figure 2.

Overview of technologies for mobile communication

Further we will describe the digital cellular systems in details in the following chapters.