A proposal of adaptive protocol relay capability for real-time media with allowable delay.

In the video and speech transmission using packets, the media synchronization control is applied, especially in the system for real-time transmission. In the system containing the media synchronization, the allowable time delay is defined, and the packet after this delay limit is discarded. In protocols such as ARQ (automated repeat request), where the packet retransmission is executed for error correction, if the delay or the error rate of the channel is large, the packet delay is greatly increased when an error occurs. The packet is discarded when the packet delay exceeds the allowable delay, which produces degradation of quality. This paper proposes an adaptive protocol relay system considering the allowable delay, in order to cope with this problem. In the adaptive protocol relay system, the protocol relay is executed at the relay node, when a certain condition for each packet is satisfied. By reducing the time spent in the packet retransmission due to the error, the number of packets that do not arrive at the receiving terminal within the allowable delay is reduced. This paper examines the effect of the protocol relay on the packet discard rate, when the proposed method is used. The condition for the adaptive control at the relay node is also discussed. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(8): 50–59, 2005; Published online in Wiley InterScience (<URL>www.interscience.wiley.com</URL>). DOI 10.1002/ecja.10031 [ABSTRACT FROM AUTHOR]