This paper presents a new construction of Maximum-Distance Separable (MDS) Reed-Solomon erasure codes based on Fermat Number Transform (FNT). Thanks to FNT, these codes support practical coding and decoding algorithms with complexity O(n log n), where n is the number of symbols of a codeword. An open-source implementation shows that the encoding speed can reach 150Mbps for codes of length up to several 10,000s of symbols. These codes can be used as the basic component of the Information Dispersal Algorithm (IDA) system used in a several P2P systems.

Abstract-In this paper we propose a low-rate coding method, suited for application-layer forward error correction. Depending on channel conditions, the coding scheme we propose can switch from a fixed-rate LDPC code to various low-rate GLDPC codes. The source symbols are first encoded by using a staircase or triangular LDPC code. If additional symbols are needed, the encoder is then switched to the GLDPC mode and extra-repair symbols are produced, on demand. In order to ensure small overheads, we consider irregular distributions of extra-repair symbols optimized by density evolution techniques. We also show that increasing the number of extra-repair symbols improves the successful decoding probability, which becomes very close to 1 for sufficiently many extra-repair symbols.

Abstract-This paper presents new FEC codes for the erasure channel, LDPC-Band, that have been designed so as to optimize a hybrid iterative-Maximum Likelihood (ML) decoding. Indeed, these codes feature simultaneously a sparse parity check matrix, which allows an efficient use of iterative LDPC decoding, and a generator matrix with a band structure, which allows fast ML decoding on the erasure channel. The combination of these two decoding algorithms leads to erasure codes achieving a very good trade-off between complexity and erasure correction capability.

In this paper, we propose a structured peer-to-peer (P2P) distribution scheme based on Fast Fourier Transform (FFT) graphs. We build a peer-to-peer network that reproduces the FFT graph initially designed for hardware FFT codecs. This topology allows content delivery with a maximum diversity level for a minimum global complexity. The resulting FFTbased network is a structured architecture with an adapted network coding that brings flexibility upon content distribution and robustness upon the dynamic nature of the network. This structure can achieve optimal capacity in terms of content recovery while solving the problem of last remaining blocks, even for large networks.

Header Compression techniques are now widely Satellite communications can strongly benefit from HC, as used in wireless and satellite communications. The main draw-any other communication means. However, some properties back of these techniques is to weaken the transmission against bit must be considered in the setting of the parameters of the HC error or packet losses. Indeed, a corrupted or missing header can lead to a non-decompression of consecutive packets and then to protocols First, the extremely large Round-Trip Time (RTT), a disconnection until the reception of a non-compressed packet. roughly 500 ms for geostationary satellite (merely one second The parameters of the header compression system should then in a DVB-S/DVB-RCS scenario), can have a strong impact be carefully determined. In this paper, we first review the main on the protocols using bidirectional links. Moreover, a large header compression protocols standardized for a unidirectional proportion of satellite applications does not have return link link. This analysis allows us to build a simple generic header prprto of stli applican doessnotlhavebrecturnal compression model depending on few parameters characterizing (e.og.lDVB-SH [1]) and then can not safely use bidirectonal a header compression protocol. The evaluation of this model in compression protocols. The second property is that, contrary cases corresponding to particular applications allows us to draw to some 3G-based protocol stacks, protocol stacks used in some first lessons for the use of header compression in Satellite satellite communications (MPE, ULE, AAL5 and now GSE) communications. do not allow the error bit to pass up to the link layer. Thus, Index Terms-Header compression protocols, packet error the channel observed by the HC protocol is a packet erasure rate, reliability, resynchronization time lal channel. In order to evaluate and parametrize HC techniques on