Along with a conventional cellular communication there are professional mobile radio communication systems, i.e. trunking mobile radio communication. Trunking communication is crucial for public and commercial enterprises and companies, which need professional and reliable radio communication by virtue of their activities.

Trunking mobile radio communication is a two-way mobile radio communication system, which uses a range of ultra-short waves. In fact the system is similar to a cellular communication: user terminals and base stations (BS), equipment to extent communication range - retransmitter and controller that operates the station, processes transmitter channels (switches them) and provides and output to city telephone network. Trunking networks may be single-zone (contain only one BS) or multizone (several BS).

Trunking communication system supports the following functions:

Instantaneous communication (0.2-0.5 s) within a group of subscribers, which may be preset;

• group members redistribution during communication session;
• call priority system;
• connection protection even in case of base station failure;
• transmission of a broadcasting signal to network subscribers;
• fast network reconfiguring.

Advantages of trunking radio communication is an economy of frequency resources, almost instantaneous connection, independent work of groups of subscribers and combination thereof into one group, if necessary, support of different types of calls, data transfer, automatic telephone exchange.

Today mobile communication trunking systems are widely used for solution of a narrow range of professional objectives and it is used by such organizations as the Ministry of Emergencies, security agencies, taxi companies, etc.