In digital speech communication over noisy high packet loss rate wireless channels, improving the overall performance of the realtime speech coding and transmission system is of great importance. A novel joint speech coding and transmission algorithm is proposed by fully exploiting the correlation between speech coding, channel coding and the transmission process. The proposed algorithm requires no algorithm delay and less bandwidth expansion while greatly enhancing the error correcting performance and the reconstructed speech quality compared with conventional algorithms. Simulations show that the residual error rate is reduced by 84.36% and the MOS (Mean Opinion Score) is improved over 38.86%.

Sensor networks, in which a large number of sensor nodes are connected with each other through communication networks, are potential to provide extensive new applications with various research and technical challenges and attracting much attention all over the world. In this paper we describe information and signal processing for sensor networks with emphasis on the concepts of collaboration and fusion as one of the most important issues for the sensor networks. We also review some basic aspects of sensor networks in terms of their features and the network architecture.