On the design and performance evaluation of compressed speech transmission over wireless channel

Wireless Transmission of a speech signal with low Bit Error Rate is one of the major challenges in Communication Systems particularly in cellular environment. In this paper a new technique to evaluate the performance of coded speech at a low data rates using Linear Predictive Coding (LPC) and Quadrature Phase Shift Keying (QPSK) modulation has been realized and simulated. A test recorded speech signal is compressed using Linear Predictive Coding and transmitted using QPSK modulation. We compare the performance of a speech signal compressed with LPC with that compressed with LPC and modulated using QPSK. It is found that the performance of the speech signal with LPC and QPSK modulation outperforms the other technique. The performance has been evaluated using Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR) Compression Ratio (CR) and Bit Error Rate (BER). The proposed scheme will serve as a useful tool for simulating the transmission of a compressed speech signal.