A N+2 protection switching system for synchronous STM-1 signals and plesiochronous 140 Mbit/s signals by using two carrier technique

The availability of a high capacity radio link mainly depends on the reliability of the radio system and the occurrence of fading events. For improving availability and quality of a radio relay link there are protection channels added to the operating channels. In the configuration 1+1 one protection channel is assigned to each operating channel. In the configuration n+2 two protection channels are provided for up to n operating channels. The article describes a protection switching system which was designed for line protection. The system is able to handle STM-1 signals (155 Mbit/s) as well as plesiochronous 140 Mbit/s signals. All special requirements concerning two-carrier systems were taken into consideration