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Information-theoretic security through linear network coding (LNC) is achievable only when a limited number of network links with linearly-independent global coding vectors are attacked, while security is not guaranteed otherwise. We incorporate LNC-based security and asymmetric-key cryptography to provide data protection in more realistic cases where the wiretapper attacks an arbitrary number of...
An information flow problem discusses how to transport information over a complicated network. It is known that a linear network code plays an essential role in a certain type of information flow problems, but it is not understood clearly how contributing linear network codes are for other types of information flow problems. One basic problem concerning this aspect is the solvability of information...
Three science and engineering problems of recent interests—index coding, locally recoverable distributed storage, and guessing games on graphs—are discussed and the connection between their optimal solutions is elucidated. By generalizing recent results by Shanmugam and Dimakis and by Mazumdar on the complementarity between the optimal broadcast rate of an index coding problem on a directed graph...
In this work, we formulate and study a data dissemination problem, which can be viewed as a generalization of the index coding problem and of the data exchange problem to networks with an arbitrary topology. We define r-solvable networks, in which data dissemination can be achieved in r > 0 communications rounds. We show that the optimum number of transmissions for any one-round communications...
Consider a set of clients in a broadcast network, each of which holds a subset of packets in the ground set X. In the (coded) cooperative data exchange problem, the clients need to recover all packets in X by exchanging coded packets over a lossless broadcast channel. Several previous works analyzed this problem under the assumption that each client initially holds a random subset of packets in X...
Although Random Linear Network Coding (RLNC) has been shown to reduce the number of transmissions for multi-cast scenarios, there is an inherent signaling overhead to achieve this benefit. Employing a large field result in less transmissions but at the cost of a large coding vector of coefficients. Conversely, a smaller field fewer bits to represent the coding coefficients, but has the drawback of...
In this work we focus on the application of an intra-flow linear random coding scheme over wireless mesh networks. We propose a cross-layer technique to balance the load between relaying nodes, considering the quality of the wireless links. We assess the performance of our proposal by means of an extensive simulation campaign carried out over the ns-3 platform, exploiting a channel model based on...
A new joint message-passing decoder is presented for use in a two-user cooperative wireless network. This decoder is designed for use with the diversity network coding scheme of Xiao et al. [1], which uses nonbinary network codes together with channel coding to achieve high diversity gains. The proposed joint decoder, together with appropriate modifications to the cooperative protocol of [1], significantly...
In this paper, we consider the network coding (NC) enabled three-phase protocol for information exchange between two users in a wireless two-way (bidirectional) relay network. Modulo-based (nonbinary) and XOR-based (binary) NC schemes are considered as information mixture schemes at the relay while all transmissions adopt pulse amplitude modulation (PAM). We first obtain the optimal constellation...
The performance of the transmission control protocol (TCP) with loss-based congestion control is considerably degraded in lossy networks (e.g., wireless networks). Implementing a network coding (NC) with TCP (TCP/NC) helps prevent this performance degradation by introducing lost packet recovery capability without retransmission at a sink by sending redundant combination packets encoded at the source...
Band Codes (BC) have been recently proposed as a solution for controlled-complexity random Network Coding (NC) in mobile applications, where energy consumption is a major concern. In this paper, we investigate the potential of BC in a peer-to-peer video streaming scenario where malicious and honest nodes coexists. Malicious nodes launch the so called pollution attack by randomly modifying the content...
Multimedia services distribution is very dependent on the quality of the communications link. Due to the nature of the related services, these are usually very sensitive to packet loss, delay and jitter, and hence service quality is immediately worsen in harsh scenarios. This paper proposes an OSI-Layer2 cooperative link layer scheme (known as GalaReS) that remarkably improves the multimedia content...
One of the promising architectures for the next generation of content distribution networks is the “cache network”, where each node has cache or local storage.We consider the index coding problem, where a central content server disseminates compressed multiple content data to each client that recovers the target content using the cached content, as side information. The coding scheme discussed in...
As the rapid growth of data, many storage systems have used erasure codes instead of replication to reduce the storage cost under the same level of reliability. Maximum-Distance- Separable (MDS) codes have been the most widely adopted, due to their optimal storage efficiency. It is well understood that the application of codes in storage systems, where the data is less frequently accessed. For the...
A few (single-source) multicast networks were recently discovered with the special property of linearly solvable over a finite field GF(q) but not over a larger GF(q′). In this paper, these networks are extended to a general class N of multicast networks. We obtain a concise condition, in terms of multiplicative subgroup orders in GF(q), for networks in N to be linearly solvable over GF(q). This full...
Suppose that a data storage service provider implements a functional MSR code based distributed storage system (DSS). Consider a scenario where the service provider has implemented an (n1; k1;B; d1; t1) functional MSR code based DSS, where B is the file that is stored. At a later point of time, due to certain considerations (such as storage cost, download bandwidth to repair failed nodes etc.), the...
The energy used to transmit a single bit of data between the devices in sensor networks is equal to the energy for performing hundreds of instructions in those devices. Thus the reduction of the data necessary to transmit, while keeping the same functionality of the employed algorithms is a formidable and challenging scientific task. We describe an algorithm called Small Set of Allowed Coefficients...
This paper considers the multiple-access relay channel in a setting where two source nodes transmit packets to a destination node, both directly and via a relay node, over packet erasure channels. Intra-session network coding is used at the source nodes and inter-session network coding is employed at the relay node to combine the recovered source packets of both source nodes. In this work, we investigate...
Access reservation based on slotted ALOHA is commonly used in wireless cellular access. In this paper we investigate its enhancement based on the use of physical-layer network coding and signature coding, whose main feature is enabling simultaneous resolution of up to K users contending for access, where K ≥ 1. We optimise the slot access probability such that the expected throughput is maximised...
Network coding tends to increase not only the end-to-end delay due to unavoidable buffering of packets, but it also increases the inter-packet delay variations (jitter) due to batching. While an increase in delay does not necessarily adversely affect throughput, sudden delay spikes may interfere with TCP’s congestion avoidance mechanism. Such spikes are a common phenomenon in coded packet networks...
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