In this paper, concealment algorithms to reconstruct lost voice packets are discussed. The algorithms are receiver based and its functionality is based on Time Scale Modifications of speech and autocorrelation of a speech signal. The proposed WSOLA algorithm is time domain approach of time scale modification and is used for many applications. Audio signal packet loss concealment is an important application of WSOLA algorithm. WSOLA algorithm extends the packets before the missing packet to conceal the lost packet. Gain controlled Waveform Similarity Overlap and Add (GWSOLA) algorithm is the modified technique of WSOLA. The gain control mechanism is used in the GWSOLA technique which adjusts the level of audio segments to be overlap added to maintain audio signal level consistent. All simulations were performed in MATLAB. Then the output reconstructed signals are compared on the basis of performance parameters MOS value and PESQ value. https://journalnx.com/journal-article/20150224