Data transmissions over wireless channels are affected by attenuation, distortion, interference and noise, which affect the receiver’s ability to receive correct information. Convolution encoding with Viterbi decoding is a powerful method for forward error correction. Convolution encoders and Viterbi decoders play an important role in digital communication especially, when channel is noisy and introduces errors in transmitted signal. The use of re-transmission methods is not efficient and has large latency measure up to the rising speed and data rates of communication links, the need of new techniques arise here to be compatible with those systems. Convolution encoding with forward error correction Viterbi decoding is designed. Implementation parameters for the decoder have been determined through simulation and the decoder should be implemented on a Xilinx FPGA SPARTAN 3E Kit. Verilog HDL language is used as a design entry.
Rakhi B. Menon : completed her B.Tech in Electronics & Communication Engineering under Mahatma Gandhi University. Currently she is pursuing M.Tech in Electronics with specialization in VLSI and Embedded System under Cochin University of Science and Technology (CUSAT).
Dr. Gnana Sheela K : received her Ph D in Electronics & Communication from Anna University, Chennai. She is working as a Professor, Department of ECE, TOC-H Institute of Science and Technology. She has published 20 international journal papers. She is life member of ISTE.
Soft decision decoding
Trace back method
The aim was the construction and design of a convolutional encoder with a Viterbi decoder that can encode a bit stream of digital information and outputs a codeword that has a capability to be transmitted to the destination and then decoded. The encoder was designed with rate 2/3. The Viterbi decoder design had been driven in such a way that it would calculate the decoding path with the minimum metric to be passed to the decoder output port. The trace back method used to decode data from metrics stored in a 16-bit decoding window to generate the decoded output. The decoder has a capability of detecting any error occurs while transmitting over the channel.
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