In the past telecommunications were dominated by telephony. But now data communications are getting more and more important. Future networks, often called Next Generation Networks (NGN), will have to cope both with bursty computer data traffic and with real-time data streams such as telephony, video, and multimedia. Packet network technology is currently regarded as the most promising NGN approach. However, the real-time capability of today’s packet network technology is still insufficient. This paper proposes a new solution for improving jitter performance of real-time communication services over packet networks in presence of high levels of packet delay variation. The idea is to synchronize both the transmitting and the receiving end systems to a stable common reference clock provided by a Global Navigation Satellite System (GNSS). GNSS-receivers installed in the access networks distribute the common time signal to the end systems. Simulations done for a scenario with G.729 coded voice communication over two medium-sized Ethernet LANs and a long-distance path in the global Internet show clearly, that a substantial reduction of the residual jitter at the receiving end can be achieved. In the case studied, standard deviation of the residual jitter was approximately 200 μs, compared to 3.0 ms with stateof- the-art packet network technology based on the Real-Time Protocol RTP.
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