Mobility aware rate control framework with RTCP for mobile multimedia services

Abstract

Currently, the requirements for multimedia services are increasing in the packet-based network. To accommodate these requirements, a number of QoS control mechanisms for non-TCP flow have been proposed [18, 19, 20, 21, 22, 23]. However, none of them considers the mobile network environment. While the quality degradation such as packet loss or delay jitter in the fixed network is caused only by the network congestion, in the mobile network, it is also caused by wireless link error and users`` mobility. To reflect the wireless environment, the paper [13] proposes the QoS control architecture using RTP monitoring agent at the intersection between wired and wireless network. It enables a sender to distinguish the wireless link error from the network congestion. However, when a mobile host makes a move it also changes the RTP monitoring agents. Thus, this mechanism cannot maintain the information of the media flow, which resides at the RTP monitoring agent, regardless of themobile host``s mobility. In this thesis, we focus our attention on quality degradation due to users`` mobility. A mobile host``s handoff incurs a burst of packet loss temporarily. The existing approaches do their QoS control procedures without discrimination between network congestion and the client``s handoff. Thus, when packet loss occurs due to a mobile host``s handoff, a sender drops down its QoS level even though the mobile host can get higher quality after handoff. Moreover, the mobile host should suffer the inappropriately lower service quality until the previous level of quality is retrieved. It takes quite a long time to retrieve original QoS level so that it offers the network the time to overcome the network congestion. To address this problem, we propose $It\{Fast Recovery Framework}$ using RTCP feedback information. This hides the quality degradation due to handoff from the sender of media flow so that it can control the transmission rate only for the network congestion. In conseque...