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We discuss some of the results achieved in the RESCUe project funded by the European Space Agencywhose goal is improving the reliability and capacity of radio links near superior conjunctions i.e. in the presence of phase and amplitude scintillation due to solar wind and solar corona. In this paper in particular the focus is on the error correcting codes that can be used to maintain acceptable values...
NEXCODE is a project promoted by the European Space Agency aimed at research design development and demonstration of a receiver chain for telecomm and links in space missions including the presence of new short low-density parity-check codes for error correction. These codes have excellent performance from the error rate viewpoint but also put new challenges as regards synchronization issues and implementation...
This paper illustrates "MisuraInternetMobile", a national project which has the aim to monitor the QoS performance provided by Italian mobile network operators. This is obtained through measurement campaigns performed on the entire national territory. The main purpose of the project is to give users the possibility to verify the performance that can be achieved in different areas by each...
We propose a variant of the well-known AONT-RS scheme for dispersed storage systems. The novelty consists in replacing the Reed-Solomon code with rateless Luby transform codes. The resulting system, named AONT-LT, is able to improve the performance by dispersing the data over an arbitrarily large number of storage nodes while ensuring limited complexity. The proposed solution is particularly suitable...
The aim of this paper is to study the performance of some coding schemes recently proposed for updating the TC channel coding standard for space applications, in the presence of jamming. Besides low-density parity-check codes, that appear as the most eligible candidates, we also consider other solutions based on parallel turbo codes and extended BCH codes. We show that all these schemes offer very...
We investigate and compare different options for updating the error correcting code currently used in space mission telecommand links. Taking as a reference the solutions recently emerged as the most promising ones, based on Low-Density Parity-Check codes, we explore the behavior of alternative schemes, based on parallel concatenated turbo codes and soft-decision decoded BCH codes. Our analysis shows...
This paper elaborates on the design of Multiple Serially Concatenated Multiple Parity-Check (M-SC-MPC) codes, that are a class of structured Low-Density Parity-Check (LDPC) codes recently proposed by the authors. M-SC-MPC codes are obtained as the serial concatenation of simple component codes, and their associated Tanner graph can be free of short length cycles. In this paper, we adopt a modified...
This paper investigates some theoretical issues related with the truncation of maximum length sequences. It is shown that truncation can have a significant impact on the autocorrelation properties, mining the applicability of these sequences in practical applications. First and second order statistics for the autocorrelation function are considered, and some new relations are presented that simplify...
In this paper we assess, through theoretical arguments and numerical simulations, the performance and complexity of a novel family of quasi-cyclic low-density generator matrix (QC-LDGM) codes. The design of such codes, denoted as ψ-unitary codes, is based on a class of binary circulant matrices recently introduced by the authors. Such matrices can have sparse inverse though being neither identity...
Under some circumstances, the power flux density produced by emissions from a spacecraft suffers the presence of spurious frequencies. This occurs, for example, when idle data with long sequences of zeros are transmitted. At high data rates, randomizers may not be able to solve the problem. Because of the need to comply with the recommendations and standards, this can reflect on severe limits on the...
We propose a novel family of bi-dimensional product codes that can be interpreted as Low-Density Parity-Check (LDPC) codes. They are based on the adoption, as components, of the so-called Multiple Serially Concatenated Multiple Parity-Check (M-SC-MPC) codes, we have recently introduced. The distinctive feature of these codes is encoding and decoding simplicity that make them a valid alternative to...
It is anticipated that the Internet traffic will continue to grow exponentially for the foreseeable future, which will require ever-growing energy (electricity). Since a lot of the Internet traffic growth comes from predictable services (such as video) there is a huge potential for decreasing future Internet energy requirements by synchronizing the operation of routers and scheduling traffic in advance,...
This paper proposes a framework for the integration of various wireless technologies among themselves and with wired backbone(s) to achieve seamless end-to-end quality of service. The basis of such integration is offered by pipeline forwarding a scheduling solution based on the deployment of a common time reference throughout the network. Time based coordination, which ensures the deterministic service...
Various solutions based on both prioritization and resource allocation have been proposed in the literature and standard bodies to support end-to-end quality of service (QoS) in wireless multihop scenarios. However, their performance is not satisfactory in terms of achievable overall network throughput and tradeoff between end-to-end delay and network utilization. This paper proposes time-driven access...
The continuous growth of the Internet might turn network power consumption into a major issue. There is a huge potential for decreasing future Internet energy requirements by synchronizing the operation of routers and scheduling traffic in advance, thus reducing complexity - e.g., header processing, buffer size, switching fabric speedup and memory access bandwidth speedup. Moreover, a lower complexity...
We propose a novel family of low-density parity-check (LDPC) codes that can be obtained as the serial concatenation of very simple components. Codes designed through the proposed approach exhibit very good performance and have a number of benefits, as high flexibility in length and rate and low complexity encoding. In addition, the systematic form of the component codes ensures rate compatibility,...
This paper presents a novel approach in traffic classification that is based on the identification of the service that generates the traffic. This method is, in some sense, orthogonal to current approaches and it can be used as an efficient complement to existing methods to reduce computation and memory requirements. Experimental results on real traffic confirm that this method is extremely effective...
The goal of this paper is to evaluate the efficiency of three versions of the well known gossip algorithm, namely: basic gossip, push-sum and broadcast, for the distributed solution of averaging problems. The main focus is on the impact of link failures that, reducing the network connectivity, decrease the convergence speed. As a similar effect occurs in non fully-meshed networks, because of a limited...
In this paper we report design examples of multiple serially concatenated multiple parity-check (M-SC-MPC) codes, we have recently proposed, that can be suitable for application in high speed wireless networks. We consider some low-density parity-check (LDPC) codes included in the mobile WiMax standard, and compare their performance with that of M-SC-MPC codes having the same parameters. Our results...
This paper presents a new class of easily invertible circulant matrices, defined by exploiting the isomorphism from the ring Mn of n times n circulant matrices over GF(p) to the ring Rn = GF(p)[x]/(xn - 1) of the polynomials modulo (xn - 1). Such class contains matrices free of 4-length cycles that, if sparse, can be included in the parity check matrix of QC-LDPC codes. Bounds for the weight of their...
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