The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In the cooperative data exchange problem, a group of wireless clients use a shared broadcast channel to exchange packets from a given set X. Each of the clients has a subset of packets in X available to it as a side information. The clients transmit linear combinations of the packets one after the other, until all clients are able to recover all packets in X. This problem arises naturally in many...
Let n ≥ 4. Can the entropic region of order n be defined by a finite list of polynomial inequalities? This question was first asked by Chan and Grant. We showed, in a companion paper, that if it were the case one could solve many algorithmic problems coming from network coding, index coding and secret sharing. Unfortunately, it seems that the entropic regions are not semialgebraic. Are the Ingleton...
Within this paper, we investigate efficient communication by means of network coding in a unicast scenario. Packets can be lost due to errors or attacks, hence, redundant data packets are necessary to ensure a successful transmission. In the ideal case, the level of redundancy should correspond to the given loss rate. However, the loss rate may be unknown in practice. We investigate methods for determining...
We present algorithms for initializing networks that use a convolutional network coding scheme and that may contain cycles. During the initialization process every source node transmits basis vectors and every sink node measures the impulse response of the network. The impulse response is then used to find a relation between the transmitted and the received symbols, which is needed for a decoding...
With random linear network coding, mixed packets contain in their headers information about the coding operations performed on the original packets to allow their recovery by the receiver. This introduces an overhead that could be significant if the packet size is relatively small w.r.t. the size of the generation. In this paper, we propose to remove the part of the added header related to the network...
We present a heuristic for designing vector non-linear network codes for non-multicast networks, which we call quasi-linear network codes. The method presented has two phases: finding an approximate linear network code over the reals, and then quantizing it to a vector non-linear network code using a fixed-point representation. Apart from describing the method, we draw some links between some network...
An increasing number of streaming applications need packets to be strictly in-order at the receiver. This paper provides a framework for analyzing in-order packet delivery in such applications. We consider the problem of multicasting an ordered stream of packets to two users over independent erasure channels with instantaneous feedback to the source. Depending upon the channel erasures, a packet which...
We consider scheduling strategies for point-to-multipoint (PMP) storage area networks (SANs) that use network coded storage (NCS).We present a simple SAN system model, two server scheduling algorithms for PMP networks, and analytical expressions for internal and external blocking probability. We point to select scheduling advantages in NCS systems under normal operating conditions, where content requests...
This work studies the potential and impact of the FRANC network coding protocol for delivering high quality Dynamic Adaptive Streaming over HTTP (DASH) in wireless networks. Although DASH aims to tailor the video quality rate based on the available throughput to the destination, it relies on the TCP protocol for reliability in data delivery. TCP is known to drop its throughput performance by several...
Let n ≥ 4, can the entropic region of order n be defined by a finite list of polynomial inequalities? This question was first asked by Chan and Grant. We show that if it were the case one could solve many algorithmic problems coming from Network Coding, Index Coding and Secret Sharing. Unfortunately, it seems that the entropic regions of order larger than four are not semialgebraic. Actually, we guess...
We study index-coding problems (one sender broadcasting messages to multiple receivers) where each message is requested by one receiver, and each receiver may know some messages a priori. This type of index-coding problems can be fully described by directed graphs. The aim is to find the minimum codelength that the sender needs to transmit in order to simultaneously satisfy all receivers' requests...
Consider the problem of exchanging information in a wireless network with random transmission delays. While the broadcast nature of the wireless medium presents many challenges, it also affords novel coding opportunities when exchanging information. However, straightforward network coding schemes do not perform well under random delay. In this paper, we rigorously define Real Time (RT) coding and...
The two-user broadcast erasure channel with feedback and memory is analyzed. It is shown that memory increases the capacity region for this scenario. Several heuristic algorithms are proposed and analyzed. Although these schemes do not achieve capacity, significant gains can be observed compared to the memoryless case.
This paper shows the potential and key enabling mechanisms for tunable sparse network coding, a scheme in which the density of network coded packets varies during a transmission session. At the beginning of a transmission session, sparsely coded packets are transmitted, which benefits decoding complexity. As the transmission continues and the receivers have accumulated coded packets, the coding density...
We present a novel decoding scheme for slotted ALOHA which is based on concepts from physical-layer network coding (PNC) and multi-user detection (MUD). In addition to recovering individual user packets from a packet collision as it is usually done with MUD, the receiver applies PNC to decode packet combinations that can be used to retrieve the original packets using information available from other...
We consider the problem of securing distributed storage systems (DSS) against an eavesdropper Eve that can observe any subset of nodes of bounded size. The goal is to construct a weakly secure DSS that leaks no meaningful information to Eve. More specifically, Eve should not be able to get any information about any individual data file or a small group of files. The key benefit of the weak security...
A limiting factor for the performance of coded packet networks is the inherent arithmetic complexity of network coding. This is in particular true for high-throughput networks such as IEEE802.11n/ac, but also for lower throughput embedded and mobile systems as well as for alternate applications of network coding such as replication of data in distributed systems. While arithmetic complexity is normally...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.