Playout scheduling technique based on normalized least mean square (NLMS) algorithm

Abstract

In the packet-switched networks, real-time quality of multimedia communications can be adversely affected by transmission delays and their variations. Depending on the network conditions (traffic, load, bandwidth, etc.) packets are transmitted through different route paths that provide the optimum flow for the packets and reach the destination with variable delays. In the presence of jitter, the received packets are first queued into a smoothing buffer before being played out. We seek an optimum receiver that is able to receive and schedule the playout of the video packets at the correct time such that the tradeoff between playout delays and packet loss are improved. In this work, we describe the packet flow in packet switched networks and identify the sources of delay that affect the real-time quality of multimedia packet communications. The Normalized Least Mean Square (NLMS) technique to schedule the play out delay for packet voice communications is reviewed and compared with Least-Mean Square (LMS) technique. We introduce packet video systems where we analyze the MPEG variable bit rate (VBR) encoder. Finally, we propose the NLMS technique in videoconferencing application to estimate video playout scheduling to obtain improved real-time video with lower packet losses.