Introduction to Information Theory

Introduction to Information Theory

• Modern digital communication is founded on Claude Elwood Shannon's 1948 paper titled "A Mathematical Theory of Communication."
• Shannon's work introduced the concept of Information Theory, addressing the challenges of reliable communication.

Shannon’s Definition of Communication

• Communication involves reproducing a message at one location that was selected from another location, either exactly or approximately.
• The meaning of messages is acknowledged but deemed irrelevant to the engineering aspects of communication.

Shannon’s Solution

• Solutions to the communication problem were proposed in Shannon's 1948 publication, shaping the foundation of Information Theory.
• The theory encompasses the processes of encoding, transmitting, and decoding messages effectively across channels.

Key Components of Information Theory

• Source: Origin of the data that needs to be communicated.
• Channel: The medium or method used for transmitting the data.
• Encoding: The process of transforming data into a suitable format for transmission.
• Decoding: The process of converting the encoded data back into its original format.

Example: Disk Storage

• Data compression is achieved through a process like zipping, while data decompression is performed by unzipping.
• CRC (Cyclic Redundancy Check): Added during encoding for error protection, allowing verification of data integrity upon decoding.

Example: VCD and DVD

• Utilizes MPEG encoding for compressing movie data and Reed-Solomon (RS) codes for error correction.
• The system consists of an MPEG encoder for encoding the data onto CD/DVD and an MPEG decoder for playback.

Importance of Error Correction

• Error protection techniques like CRC and Reed-Solomon codes are crucial for maintaining data integrity and ensuring effective communication.