A real-time voice service with the adaptive packet loss recovery scheme in the hybrid residential gateway system

This paper presents a real-time voice service with the adaptive packet loss recovery scheme based on the H.323 protocol, which is one of the service functionalities of the hybrid residential gateway system. The proposed scheme analyzes the characteristics of packet losses based on the Gilbert model, and then describes a mechanism that can recover the lost audio packets with the offset redundant data. Using information periodically reported by a receiver, the sender dynamically adjusts the amount and the offset values of redundant data, with a constraint of minimizing the bandwidth consumption of links. Since the wireless environments could be often characterized by frequent and consecutive packet losses, loss recovery mechanisms need to deal with both the random and consecutive packet losses efficiently. To achieve this, the suggested mechanism uses relatively large and discontinuous exponential offset values. To verify the effectiveness of the mechanism, we extended and implemented RTP/RTCP protocols and applications in the hybrid residential gateway system. The experimental results show that our mechanism, with exponential offset, achieves remarkably low complete packet loss rate and adapts dynamically to the fluctuation of the packet loss pattern in the wired and wireless environments.