Maximum Likelihood Decoding

Keywords: maximum likelihood decoding, digital communication, data storage, noise, interference, wireless communication systems, optical communication systems, digital storage systems, probability, likelihood estimation, python Introduction Maximum likelihood decoding is a technique used to determine the most likely transmitted message in a digital communication system, based on the received signal and statistical models of noise and interference. … Read more

Hard and Soft decision decoding

What are hard and soft decision decoding Hard decision decoding and soft decision decoding are two different methods used for decoding error-correcting codes. With hard decision decoding, the received signal is compared to a set threshold value to determine whether the transmitted bit is a 0 or a 1. This is commonly used in digital … Read more

Reed Solomon Codes – Introduction

The Hamming codes described in the previous articles are suitable for random bit errors in a sequence of transmitted bits. If the communication medium is prone to burst errors (channel errors affecting contiguous blocks of bits) (missing symbols are called erasures ), then Hamming code may not be suitable. For example in CD, DVD and … Read more

Hamming Code : construction, encoding & decoding

Keywords: Hamming code, error-correction code, digital communication, data storage, reliable transmission, computer memory systems, satellite communication systems, single-bit error, two-bit errors. What is a Hamming Code Hamming codes are a class of error-correcting codes that are commonly employed in digital communication and data storage systems to detect and correct errors that may occur during transmission … Read more

Shannon theorem – demystified

Shannon theorem dictates the maximum data rate at which the information can be transmitted over a noisy band-limited channel. The maximum data rate is designated as channel capacity. The concept of channel capacity is discussed first, followed by an in-depth treatment of Shannon’s capacity for various channels. Introduction The main goal of a communication system … Read more

Random Variables, CDF and PDF

Random Variable: In a “coin-flipping” experiment, the outcome is not known prior to the experiment, that is we cannot predict it with certainty (non-deterministic/stochastic). But we know the all possible outcomes – Head or Tail. Assign real numbers to the all possible events (this is called “sample space”), say “0” to “Head” and “1” to … Read more