Leistungsbewertung von TETRA-Mobilfunksystemen durch Analyse und Emulation ihrer Protokolle

摘要

The European trunked radio standard Terrestrial Trunked Radio (TETRA) is a pure digital information technology usable for small band voice and data transmissions. TETRA marks a new milestone regarding the efficiency of security and business related telecommunication applications. Due to its advanced capability to shield off interception, jamming, and manipulation, TETRA is especially of great intererst for public safety organisations. Additionally, TETRA systems are well suited to police forces, fire brigades, rescue services, etc., because of its group call services and the possibility to maintain radio connections without a network infractructure (walkie talkie mode). TETRA networks are about to be implemented in Europe and Asia. Owing to forthcoming investments of several billions of Euros, an exact knowledge of the technical features of TETRA is essential for network planning and maintenance. It is the main goal of this thesis to evaluate the performance of TETRA systems. In order to carry out these assessments with the help of formal, object-oriented methods, new tools and methods have been developed as part of this thesis for stochastic, event-driven simulations, especially of TETRA systems. Simulations at system level use one TETRA cell and a ring of six co-channel interferer cells. The protocol stacks Voice plus Data (V+D) and Packet Data Optimised (PDO) of the mobile and base stations located in these cells are formally specified in the Specification and Description Language (SDL). The meaning of the parameters of the TETRA random access is examined in hot spot scenarios under consideration of co-channel interference. Furthermore, the effect of collision resolution algorithms and reservation allocation strategies adapted to TETRA is investigated with regard to grade of service, quality of service, throughput, packet delay, and call setup time.