Sparse graph codes such as low-density parity-check codes can offer a performance that approaches the previously elusive Shannon capacity with reasonable practical computational complexity. Finally, a design framework is provided for DLT coding schemes, to jointly improve the transmission efficiency and erasure floor performance. The number of downloads is the sum of all downloads of full texts. From Wikipedia, the free encyclopedia. The thesis is divided into two parts. The second part of the thesis deals with the analysis and design of rateless codes for multi-point communication.

By using this site, you agree to the Terms of Use and Privacy Policy. The requirements of erasure code design for data storage, particularly for distributed storage applications, might be quite different relative to communication or data streaming scenarios. In practice, the broadcast is typically scheduled for a fixed period of time by an operator based on characteristics of the network and receivers and desired delivery reliability, and thus the fountain code is used at a code rate that is determined dynamically at the time when the file is scheduled to be broadcast. A detailed survey about fountain codes and their applications can be found at. An algorithm is developed based on the extrinsic information transfer EXIT chart to obtain optimized degree distributions of LT coded differential modulator systems in terms of convergence performance.

We optimize the proposed DLT codes in terms of transmission efficiency; thus exhibiting better performance as compared to their conventional counterparts at the expense of increased computational complexity.

The number of downloads is the sum of all downloads of full texts. From Wikipedia, the free encyclopedia. An algorithm is developed based on the extrinsic information transfer EXIT chart to obtain optimized degree distributions of LT coded differential modulator systems in terms of convergence performance.

This code is able to recover a source block from any set of encoded symbols equal to the number of source symbols in the source block with high probability, and in rare cases from slightly more than the number of source symbols in the source block. The thesis is divided into two tateless.

The requirements of erasure code design for data storage, particularly for distributed storage applications, might be quite different relative to communication or data streaming scenarios. The idea is then extended to a multi-way relay network where a linear-programming design framework is outlined for optimizing degree distributions in terms rateoess transmission efficiency.

Another application is that of hybrid ARQ in reliable multicast scenarios: Thesis kB downloads. The first part considers the analysis and design of rateless codes for point-to-point communication. Liquid Cloud Storage is based on using a large erasure code such as the RaptorQ code specified in IETF RFC which provides significantly better data protection than other systemsusing a background repair process which significantly reduces the repair bandwidth requirements compared to other systemsand using a stream data organization which allows fast access to data even when not all encoded symbols are available.

# Analysis and Design of Rateless Codes

In addition, since the bandwidth and communication load between storage nodes can be thesid bottleneck, codes that allow minimum communication are very beneficial particularly when a node fails and a system reconstruction is needed to achieve the initial level of redundancy. A fountain code is inherently rateless, and as a consequence, such codes may potentially generate an unlimited number of encoded symbols on the fly.

Finally, a design framework is provided for DLT coding schemes, to jointly improve the transmission efficiency and erasure floor performance. To this end, we commence by considering the concatenation of Luby transform LT codes, which were the first practical realization of rateless codes, with differential modulators to exploit the inherent coding gain of differential modulations.

An algorithm rateeless developed based on the extrinsic information transfer EXIT chart to obtain optimized degree distributions of LT coded differential modulator systems in terms of convergence performance.

Retrieved from ” https: To observe the consequences of the rateeless encoding scheme, the convergence behavior of the proposed LT code is analyzed using EXIT charts, and shown to be similar to the convergence performance of conventional LT codes.

The number of downloads is the sum of all downloads of full texts.

## Fountain code

The first part considers the analysis and design of rateless codes for point-to-point communication. Views Read Edit View history. A fountain rzteless is optimal if the original k source symbols can be recovered from any k encoding symbols. For complexity-constrained applications, we construct low-complexity LT codes and devise a reduced-complexity LT decoder for transmission over noisy channels.

Handbook of Mobile Broadcasting: In fact, repair latency might sometimes thwsis more important than storage space savings.

Then, we delve deeper into the characteristics of LT codes with the objective of improving the error floor performance over noisy channels. It may include eg previous versions that are now no longer available. This idea is then extended to LT codes for transmission over erasure channels and a design framework is developed to jointly improve the transmission efficiency and erasure floor performance. Finally, a design framework is provided for DLT coding schemes, to jointly improve the transmission efficiency and erasure floor performance.

The second part of the thesis deals with the analysis and design of rateless codes for multi-point communication. This code has an average relative reception overhead of 0. For complexity-constrained applications, we construct low-complexity LT codes and devise a reduced-complexity LT decoder for transmission over noisy channels. The thesis is divided into two parts. Thus due to the rateless property, these codes are suitable for transmission over time varying channels.