In order-to-realize speech communication by means of best-effort packet communications, which is inherently unsuitable for real-time processing, VoIP addresses the fundamental problem of degradation of communications quality by errors such as packet loss and delay. In the present research, based on the two-sided PWR method, an error concealment technique based on waveform replication, a method of performing error concealment more effectively by taking account of the pitch variations of the speech data in the loss frame is proposed. Evaluation experiments with SNR, PESQ, and DMOS as the metrics suggest the effectiveness of the proposed method. (c) 2005 Wiley Periodicals, Inc.