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Distributed Storage Systems (DSS) have seen increasing levels of deployment in data centers and in cloud storage provider networks. They provide efficient and cost-effective ways to store large amounts of data and ensure resilience to failures by using mirroring and coding schemes at the block and file level. While mirroring techniques provide an efficient way to recover lost data, they require excess...
Multipath TCP (MPTCP) is a promising extension of TCP to spread data across several subflows enabling multiple path support. Like TCP, MPTCP suffers from performance degradation when deployed in wireless networks. It tends to interpret random link losses as congestion signals. Yet, the protocol is showcased for handheld devices with multiple radios to enable throughput aggregation and seamless handover...
A lot of research shows that network coding can significantly improve the performance of multi-cast transmission. However, due to the inherent disadvantage of network coding, it is very vulnerable to pollution attacks in which adversaries can inject bogus data. Moreover, those bogus data will be used with legitimate data at the downstream nodes, resulting in the failure of decoding original data as...
Network coding is becoming a very important technology to improve the reconstructing performance of distributed storage systems due to its high reliability and low redundancy. Update is a typical and important operation involved in the network-coding-based systems. However, the overhead incurred by the update operation has a significant impact on the system performance. Traditionally, the small updated...
Caching is an effective way to reduce peak-hour network traffic congestion by storing some contents at user's local cache. Maddah-Ali and Niesen (MAN) initiated a fundamental study of caching systems by proposing a scheme (with uncoded cache placement and linear network coding delivery) that is provably optimal to within a factor 4.7. In this paper, when the cache contents and the user demands are...
With network coding, data flows from the source to the destinations may be jointly coded in some intermediate nodes to achieve the maximum network capacity. There is scarcely any theory to systematically model and evaluate the loss of network coding. Without such a theory, the analysis of network coding under various settings is far from practical. To fill the vacancy, we introduce a loss model into...
In network coding theory, when wiretapping attacks occur, secure network coding is introduced to prevent information from being leaked to adversaries. In practical network communications, secure constraints vary with time. How to effectively deal with information transmission and information security simultaneously under different security-levels is introduced in this paper as variable-security-level...
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...
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, by right of the concise form and remarkable effect, has been applauded around the world since its emergence especially in the field of wireless communication. However, we find the superiority of network coding may be concealed by the over redundant information in coded packets under certain circumstances. That is, the back-and-forth coding at intermediate nodes makes the old information...
Caching decreases content access time by keeping contents closer to the clients. In this paper we show that network coding chunks of different contents and storing them in cache, can be beneficial. Recent research considers caching network coded chunks of same content, but not different contents. This paper proposes three different methods, IP, layered-IP and Greedy algorithm, with different performance...
The problem of minimizing the decoding delay in Generalized instantly decodable network coding (G-IDNC) for both perfect and lossy feedback scenarios is formulated as a maximum weight clique problem over the G-IDNC graph in . In this letter, we introduce a new lossy G-IDNC graph (LG-IDNC) model to further minimize the decoding delay in lossy feedback scenarios. Whereas the G-IDNC graph represents...
Inspired by the discrepancy between past theoretical analysis and real measurements for high-load scenarios for inter-session network coding, we pinpoint and analyze the source of this discrepancy in wireless networks implementing a CSMA/CA medium access scheme. Our analysis shows that CSMA/CA is very sensitive to asymmetric channel losses caused by channel conditions. Leveraging this analysis, we...
The advantages of coded cooperative data exchange has been studied in the literature. In this problem, a group of wireless clients are interested in the same set of packets (a multicast scenario). Each client initially holds a subset of packets and wills to obtain its missing packets in a cooperative setting by exchanging packets with its peers. Cooperation via short range transmission links among...
We consider a network where multiple sources communicate via a single relay to sinks with non-uniform and unequal demands. The LT distributions employed at the sources may be ill-matched to the demands of the sinks connected to the relay. We consider a probabilistic “morphing” of two or more fountain-encoded streams into a single stream better suited for the demand patterns downstream of the relay...
In this paper, we study delivery of two nested message sets over combination networks with an arbitrary number of receivers, where a subset of receivers (public receivers) demand only the lower priority message and a subset of receivers (private receivers) demand both the lower and the higher priority messages. We give a complete rate region characterization over combination networks with three public...
Recent research indicates that packet transmission employing random linear network coding can be regarded as transmitting subspaces over a linear operator channel (LOC). In this paper we propose the framework of linear operator broadcast channels (LOBCs) to model packet broadcasting over LOCs, and we do initial work on the capacity region of constant-dimension multiplicative LOBCs (CMLOBCs), a generalization...
We consider the multiple unicast problem under network coding over directed acyclic networks when there are two source-terminal pairs, s1 — t1 and s2 — t2. Current characterizations of the multiple unicast capacity region in this setting have a large number of inequalities, which makes them hard to explicitly evaluate. In this work we consider a slightly different problem. We assume that we only know...
In this paper, we study the effect of packet feedback loss events on the broadcast completion delay performance of instantly decodable network coding. These feedback loss events result in a continuous lack of knowledge about the reception status at different subsets of receivers. This lack of knowledge creates a challenge in selecting efficient packet combinations in subsequent transmissions. To solve...
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