International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 05 | May -2017
p-ISSN: 2395-0072
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Review Paper On Implementation Of Low Power Hard Decision Viterbi Decoder In VLSI Shweta Anand Wankhede, Prof.Nilesh Bodne Shweta Anand Wankhede Department Of Electronics and Communication Engineering Vidarbha Institute Of Technology Nagpur,Maharashtra Prof.Nilesh Bodne Department Of Electronics and Communication Engineering Vidarbha Institute Of Technology Nagpur,Maharashtra ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - For correction of errors at the receiver end,
information. To remove this error from the transmission channel, Viterbi decoder is used.
convolutional encoding is used which is a forward error correction technique .Viterbi decoding is the best technique for decoding the convolutional codes but it is limited to smaller constraints length. This paper proposed implementation of low power hard decision viterbi decoder on Xilinx. The techniques used for decoding the data are traceback method and register exchange method.Register exchange method is not appropriate for decoders with long constraint lengths. Therefore in this paper traceback method is used for decoder with long constraint lengths.
2. CONVOLUTION ENCODER Convolution coding with Viterbi decoding is a forward error correction technique that is particularly suited to a channel in which transmitted signal is corrupted mainly by noise [1].
Key Words: Viterbi decoder, convolution encoder, low power, VLSI.
1. INTRODUCTION There are many methods proposed in the error correction field. Viterbi algorithm is one of the best known method. Error correction method consists of three main parts: the convolutional encoding, the error disturbance, and the viterbi decoding. Firstly original data will be convoluted using its specific convolution formula which produce a codeword. Each codeword consists of 2-bits. The original data and its redundant bit represent a codeword. Therefore, if errors occur in the data transmission, we can still manage to reconstruct the correct data using viterbi algorithm.
Figure 1: Convolutional encoder with constraint length k=9 and code rate (k/n)=1/2 In most of real time applications like audio and video applications, the convolutional codes are used for error correction [2]. Parameters for convolutional codes are the following: code rate (R), generating polynomial g (n), and number of input bits (k), number of output bits (n) and constraint length (K). The number of transmitted bits per input bit is known as code rate, e.g., a rate ½ encodes 1 bit and produces 2 bits for transmission.
1.1 PROPOSED WORK The two techniques used for decoding the data are traceback method and register exchange method. Register exchange method uses dynamic register due to which power required is more. Therefore traceback method is used with butterful structure that consumes less power. Viterbi decoder decodes the convolutional codes. But during the transmission of data, error gets added in the original
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