# What is the difference between hard decoding and soft decoding?

## What is the difference between hard decoding and soft decoding?

Whereas a hard-decision decoder operates on data that take on a fixed set of possible values (typically 0 or 1 in a binary code), the inputs to a soft-decision decoder may take on a whole range of values in-between.

**What is meant by soft decoding?**

Soft decision decoding is a class of algorithms that takes a stream of bits or a block of bits and decodes them by considering a range of possible values that it may take. It considers the reliability of each received pulse to form better estimates of input data.

### What is Viterbi decoding scheme?

The Viterbi algorithm is the most resource-consuming, but it does the maximum likelihood decoding. It is most often used for decoding convolutional codes with constraint lengths k≤3, but values up to k=15 are used in practice. Viterbi decoding was developed by Andrew J.

**Which decoding method is used for Viterbi algorithm?**

Viterbi algorithm is utilized to decode the convolutional codes. Again the decoding can be done in two approaches. One approach is called hard decision decoding which uses Hamming distance as a metric to perform the decoding operation, whereas, the soft decision decoding uses Euclidean distance as a metric.

#### How does Viterbi algorithm work?

The purpose of the Viterbi algorithm is to make an inference based on a trained model and some observed data. It works by asking a question: given the trained parameter matrices and data, what is the choice of states such that the joint probability reaches maximum?

**What is soft demodulation?**

Abstract—Soft demodulation is a basic module of traditional communication receivers. It converts received symbols into soft bits, that is, log likelihood ratios (LLRs). However, in the non- ideal additive white Gaussian noise (AWGN) channel, it is difficult to accurately calculate the LLR.

## Why do we need a decoder?

The decoder is an electronic device that is used to convert a digital signal to an analog signal. It allows a single input line and produces multiple output lines. The decoders are used in many communication projects that are used to communicate between two devices.

**What is Viterbi decoding in digital communication?**

The Viterbi algorithm is based on the Maximum-Likelihood decoding technique. The main purpose of the decoder is to select the code word with the minimum distance between the received signal and the code word. The Viterbi algorithm can use either hard or soft decisions.

### What is the purpose of the Viterbi algorithm?

**What is Viterbi used for?**

Originally conceived by Andrew Viterbi as an error-correction scheme for noisy digital communication, the Viterbi algorithm provides an efficient method for Forward Error Correction (FEC) that improves channel reliability.

#### Is Viterbi algorithm optimal?

We show that the Viterbi algorithm runtime is optimal up to subpolynomial factors even when the number of distinct observations is small.