Advanced VoIP systems for mobile use

The use of VoIP in moving vehicles on UMTS , CDMA 2000 and LTE presents challenges due to varying signal levels, handover interruptions,  intermittent lack of coverage etc. Car antenna solutions need to be optimized for coping with difficult conditions. By maintaining several active connections simultaneously over several  operators and/or radio techniques, such as LTE and CDMA, access to functioning VoIP can be ascertained. Stationary routers can be used to link phone calls to available open connections at activated mobile routers. As with fixed land line connections, calls can be transferred to subsequent numbers and handled by the first open connection. In one already implemented set up, a voip call aimed at a router A at a fixed location is transferred to the mobile router B if this router is activated. The transfer can be further directed to a third router C which is outside the car if this router is activated when the car stops for a visit. This flexibility is not achieved with the GSM system which lacks the option to only transfer calls to the most recently activated device. Furthermore, transfers are based on IP and do not incur any costs.

The aim of this thread is to discuss possible solutions - also auf Deutsch.