Data Transmission Using Efficient FEC over CDMA Channel

Still Image/Video is one of the most important and also one of the most challenging types of traffic on communication networks. One of the challenges arises because communication networks can insert errors into still Image/Video, and also compressed image or compressed Video is fragile in the presence of errors; that are a single error can propagate over a large portion of the Image/Video. This thesis describes how to protect the content of still Image/Video during transmission by employing error correcting codes. It deals with the concept of transmitting packets with redundancy embedded in it for attempting error recovery and improving the quality at the receiver side. The effect of bit errors on the overall Image/Video quality has been studied. This thesis throws light on the importance of each bit in an Image/Video frame to the overall received quality. We have adopted BCH codes to improve the quality of image or Image/Video. Two types of FEC schemes have been implemented. In the first FEC scheme, data is not prioritized and various segments in the image or Image/Video stream are given equal importance. BCH (63, 51, 2) is used for this case. In the second scheme, a stronger FEC is applied to the first frame (the first I frame) as the important data is found in it. Hence BCH (63, 24, 7) is used for the first frame and BCH (63, 57, 1) is used for the rest inter frames. The main aim of the algorithm is to strengthen the Image/Video stream against most possible error cases and also reduce the percentage of the overhead bits arising because of BCH coding. Keywords— spread spectrum, compression coding, channel control, Run length coding, convolutional code