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Aim

Pretest

Theory

Procedure

LDPC Codes

Posttest

References

Feedback

LDPC Codes: Introduction

Choose difficulty:

Beginner

Intermediate

Advanced

In an LDPC code, the Tanner graph is used to represent which of the following?

a: Codeword structure Explanation

Explanation

b: Parity-check matrix Explanation

Explanation

c: Generator matrix Explanation

Explanation

d: Transmission channel Explanation

Explanation

The column weight of an LDPC code's parity-check matrix refers to:

a: The number of rows in the matrix. Explanation

Explanation

b: The number of ones in each column. Explanation

Explanation

c: The number of variable nodes connected to each check node. Explanation

Explanation

d: The number of columns in the matrix. Explanation

Explanation

In a Tanner graph of an LDPC code, what do the variable nodes represent?

a: Parity check equations Explanation

Explanation

b: Codeword coordinate Explanation

Explanation

c: Rows of

H

Explanation

d: Error correction bits Explanation

Explanation

How many edges would the Tanner graph corresponding to the matrix

H = \begin{bmatrix} 1 & 1 & 0 & 1 & 0 & 0 \\ 0 & 1 & 1 & 0 & 1 & 0 \\ 1 & 0 & 1 & 0 & 0 & 1 \end{bmatrix}

contain?

a: 4 Explanation

Explanation

b: 8 Explanation

Explanation

c: 9 Explanation

Explanation

d: 20 Explanation

Explanation

Which of the following best describes the meaning of a

\textit{regular}

LDPC code?

a: All rows have the same weight, and all columns have the same weight. Explanation

Explanation

b: The parity check matrix has full rank. Explanation

Explanation

c: The code has a constant block length. Explanation

Explanation

d: All entries of the parity check matrix are either 0 or 1. Explanation

Explanation

Which of the following statements about Tanner graphs is correct?

a: A Tanner graph is a unipartite graph. Explanation

Explanation

b: A Tanner graph has no variable nodes. Explanation

Explanation

c: A Tanner graph represents a bipartite graph. Explanation

Explanation

d: Tanner graphs are irrelevant to LDPC codes. Explanation

Explanation

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