A comparison of modified convolutional codes with sequential decoding and turbo codes

In an effort to achieve bandwidth efficient but reliable communications at lower signal-to-noise ratios, NASA is evaluating its presently developed coding techniques by conducting simulations and tests. These tests will form a basis for comparison of these systems and some newly proposed systems for NASA´s coding standards. NASA´s present coding standards support convolutional inner codes and Reed-Solomon outer codes. Simulations of coding techniques under development indicate that some variation of convolutional codes with sequential decoding achieve a performance close to that of turbo codes. Compared to the turbo codes these convolutional codes advantages in computational complexity and aspects such as free and open architectures