The Research Of Fault Recovery Technology In TETRA System

TETRA system is a radio dedicated command and dispatch system, which is widely used in military, police, public security and other communication systems where the dispatching is urgently needed. More attention should be payed on the research and development of reliability design in TETRA, to match the the demand of users. Fault monitoring and recovery technique are the key parts of reliability design, what are this paper will focus on.The study on monitor and recovery emphasizes the design and implementation of base station controller program. First of all, the existing condition analysis of the reliability design in the TETRA system is given. Then we present the corresponding system architecture, the design of network management, upper computer, fault alarm, etc., which can achieve fault monitoring of system. And the design is based on the devices in the system, so no new investment is needed. The applications of main/standby switch and fallback mode can enhance the self-restoration capability of the system entirely. The proposed dependent hot standby redundancy can ensure fast and reliable switch. Furthermore, fallback mode can maintain the services when the system under link failure.Finally, we propose a dynamic channel re-allocation scheme(DCRAS) to reduce the influence of slots binding in TETRA networks. The simulation results show that DCRAS can considerably reduce the packet data blocking probability and obviously increase the channel utilization at the expense of increased voice blocking probability. Furthermore, the performance is further improved when packet data call for more adjacent channels.