Designing Tornado Codes as Hyper Codes for Improved Error Correcting Performance

Digital services are increasingly being delivered to user terminals over wireless multicast networks. When the target service requires uncorrupted data delivery, there is an increasing need for developing techniques for reliable content delivery. In multicast networks, the typical way of providing reliable content delivery is to apply forward error correcting techniques (FEC). In this paper, we introduce a modification to the Tornado code, where we combine the structures of Tornado codes and Hyper codes. Standard Tornado codes have the drawback that they are dependent on the error distribution on the data path. By combining the Tornado code with a Hyper code, we decrease the probability of the Tornado decoder failing due to inopportune error distribution in the source data. We demonstrate, based on a simulated transmission channel, that the error correcting performance is improved, at the cost of slightly longer decoding times, by using a combination of Hyper codes and Tornado codes, compared to the standard Tornado codes.