Turbo Codes

Turbo Codes constitute a major development in the field of Forward Error Correction (FEC).

Exhibiting performance approaching the Shannon limit, Turbo Codes (TC) have seen rapid adoption in the design of modern digital communication systems.

Technical Specs

TC Module Credentials

The Turbo Codes module was developed in collaboration with Dr. Matthew Valenti of West Virginia University and provides support for parallel concatenated turbo codes, including the UMTS specification.

Additional information is also available at the Iterative Solutions web site.

Decoder Implementation

The Embed/Comm TC decoder is of a flexible design. It allows the user to select the implementation of the max* operator computation, and it provides the option of using dynamic halting.

Since the max* operator constitutes a significant portion of the overall decoder complexity, its manner of implementation directly affects the performance and speed of the decoding process. Four variants of the algorithms are available: log-MAP, max-log-MAP, constant-log-MAP, and linear-log-MAP.

Because a decoder rarely requires the maximum number of iterations to converge, using an early stopping criterion will improve throughput.


The Turbo Codes Blockset

The TC blockset adds power to Embed/Comm simulations by providing support for the PCCC variety of turbo codes.

It features efficient encoder and decoder designs, including support for the UMTS specification.
The Embed/Comm TC decoder uses a simple and effective stopping criteria based on the log-likelihood ratio.

TC Module Block Listing

The following blocks are included in the Embed/Comm TC module:
• UMTS Interleaver Generator
• S-Random Interleaver Generator
• Generic Turbo Code Encoder (PCCC)
• Generic Turbo Code Decoder (PCCC)
• UMTS Turbo Code Encoder
• UMTS Turbo Code Encoder