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The recent popularization of hand-held mobile devices, such as smartphones, enables the inter-connectivity among mobile users without the support of Internet infrastructure. When mobile users move and contact each other opportunistically, they form a Delay Tolerant Network (DTN), which can be exploited to share data among them. Data replication is one of the common techniques for such data sharing...
A distributed space-time block code (STBC) based on a decode-and-forward (DF) protocol is proposed for two-path successive relaying. By making the two relay nodes transmit and listen in turn, the proposed distributed STBC can achieve not only full rate but also full diversity when the relay nodes can correctly decode the information symbols from the source node and when the inter-relay channels are...
This paper focuses on the security problem in unreliable wireless ad hoc networks when involving network coding. A typical example of misbehaviors by bad nodes is presented to show the misbehavior propagation problem of network coding. To reduce the influence of bad nodes, we propose to combine network coding with trust scheme. In our trusted network coding, a trust model is established according...
The usual network message transmission is based on store and forward mechanism. The network node does not process the network messages. Network coding theory has changed this routing form. Toimprove the network transmission capacity, it allows nodes to encode the transmitting messages. Some researches show that the network coding theory makes the node reach the maximal network traffic introduced by...
Network coding is an efficient technique to increase network capacity. COPE is a promising forwarding mechanism which can utilize network coding in a practical way. Different routing algorithms utilizing COPE may have different gains from network coding. In this paper, we discuss the importance of coding-aware routing and the tradeoff between load-balanced and coding-aware routing. We then propose...
In this paper, we show how to compute the Slepian-Wolf lower bound for the reconciliation of physical layer secret keys between two radio terminals. Two coding approaches, including the syndrome method and the parity method, have been proven to require the same number of bits exchanged between two terminals for the reconciliation in the noiseless environment. We also present a practical coding approach...
The success of P2P file sharing systems inspired the development of P2P streaming systems for delivering online multimedia service in the last few years. The capacity of P2P streaming systems, i.e., how many peers can be concurrently serviced by the system, depends on system configurations including network bandwidth, overlay network formation, QoS constraints, membership management, peer selection,...
The recent studies have shown that network coding can benefit peer-to-peer (P2P) content distribution network (CDN) since it eases the packet scheduling and balances the network load by utilizing peers' resources to code. But better coding performance costs increasing computation complexity and buffering space, which may result in higher delay and decoding failure. The situation will be worse if the...
At present, many application layer multicast protocols (ALM) based on multiple description coding (MDC) have been proved to be more scalable and robust than traditional multicast protocols in practical environment. In this paper, we propose an ALM system called SMD for streaming media based on MDC to address the problem of synchronization of available descriptions among maximum hosts. SMD concentrates...
In this paper, we propose a localized network-coding-based packet forwarding protocol for wireless networks, called Opportunistic Asynchronous Information dissemination (OASIS), based on COPE. OASIS not only inherents two features from COPE, opportunistic listening and opportunistic coding, but also introduces a new one, opportunistic information dissemination, which aggressively encodes as many packets...
The traditional way to achieve high data availability in structured P2P network is to replicate the data items preserved on the node to its neighbor nodes. However, in some heterogeneous structured P2P networks, the neighbor nodes are always close to each other in locality. Therefore, if some local disaster happened, it is very likely that some data items would be permanent lost. Moreover, this traditional...
COPE appears as the first wireless network coding approach which can improve the throughput of Wireless Mesh Networks (WMNs). But the established routes in COPE may result in fairly limited coding opportunities and low throughput gain. Although excessive intersections of flows can bring forth more coding opportunities, they may make some nodes overloaded, and decrease the throughput. Furthermore,...
In this paper, we propose a combined SVC-MDC (scalable video coding & multiple description coding) video coding scheme using the multi-core parallel programming paradigm for P2P video streaming, which is denoted Co-SVC-MDC. To date, P2P video streaming applications are widely popular and emphasized, e.g., PPstream and PPlive, because of higher transmission speed and data availability. However,...
With the popularity of VoIP, Push-To-Talk (PTT) services over the IP networks have gained their momentum. This research aims at essential design issues for the quality of service of PTT services. We explore the relationship between the speech quality and system design issues. MOS (Mean Opinion Score), which is raised by the ITU-T (International Telecommunication Union) as one of the most common benchmarks,...
Delay-tolerant networks (DTNs) have the capacity to interconnect the devices in roomy regions unlike todaypsilas networks. In this paper, we propose a routing scheme named time interval routing (TIR) to increase deliver ratio and decrease deliver latency in DTNs. TIR, only using limited and local information as well as simple algorithm, chooses the node in transmission range with the least time interval...
Network coding has recently been applied to wireless networks and has achieved some initial success. Researches in wireless network coding have been mostly focusing on utilizing the broadcast nature of the wireless networks. In this paper, we propose a novel network coding framework for wireless relay networks that also takes into consideration the fading and error prone nature of the wireless networks...
Network coding provides the possibility to maximize network throughput and receives various applications in traditional computer networks, wireless sensor networks and peer-to-peer systems. However, the applications built on top of network coding are vulnerable to pollution attacks, in which the compromised forwarders can inject polluted or forged messages into networks. Existing schemes addressing...
A distributed space-frequency (SF) coded cooperative technique is proposed for broadband wireless ad-hoc networks, where both the channels from the source node to relay nodes and from the relay nodes to the destination node are characterized by frequency-selective fading. Using an SF coding at the source node and a circular shift at each relay node, we propose a scheme that can achieve both cooperative...
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