(V KEERTHY RAI)

Turbo coding is an advanced forward error correction algorithm. It will be a standard component in third generation (3G) wireless communication systems, like those employing Wideband Code Division Multiple Access (W-CDMA). W-CDMA systems must handle online multimedia applications as well as conventional voice communications. The principle of Turbo Coding is that the encoder generates a data stream consisting of two independently encoded data streams and a single un encoded data stream. The two parity streams are weakly correlated due to the interleaving. In the turbo decoder, the two parity streams are separately decoded with soft decision outputs, referred to as.extrinsic. information. The strength of the turbo decoding results from the sharing of the extrinsic information in a number of iterations. The extrinsic information is passed from one parity decoding step to the other, from one iteration to the other. In this project, we decompose low complexity turbo decoder architecture by using SB/DB modes. These are the extra pattern in the generation but We proposed that our architecture employs power consumption in the order of Mw power by dynamically using SB/DB Mode algorithm depending upon the Wireless Environment. Compared to existing the proposed method low complexity and power consumption. Key Terms: Error-correcting code (ECC),Log-BCJR algorithm, turbo code