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.
Network codes designed specifically for distributed storage systems have the potential to provide dramatically higher storage efficiency for the same availability. One main challenge in the design of such codes is the exact repair problem: if a node storing encoded information fails, in order to maintain the same level of reliability we need to create encoded information at a new node. One of the...
Churn resilience is an important issue for current Peer-to-Peer(P2P) networks, where peers dynamically and freely join and leave the system with or without warning. In this paper we focus on improving an existing anonymous peer-to-peer network design [8] by adding churn-resilience to it. Churn resilience is achieved by employing the properties of threshold secret sharing schemes. The paper describes...
LandHouse is a distributed storage system that is made up of some regular graphs and is organized by distributed hash table. However, the master server is the performance bottleneck of LandHouse. Moreover, when using traditional data block strategy, the regular graph Petersen can't work to its best extent. Therefore, a new architecture with modified node deployment is designed to optimize the original...
Network coding is a promising technology which allows coding of multiple packets in routers. Random linear network coding (RLNC), a distributed network coding scheme, insists each node to forward independent random linear combinations of incoming packets through its outgoing links. RLNC appends a header which contains the information about how the linear combinations are taken. We observe that some...
Link failures in wide area networks are common. To recover from such failures, a number of methods such as SONET rings, protection cycles, and source rerouting have been investigated. Two important considerations in such approaches are the recovery time and the needed spare capacity to complete the recovery. Usually, these techniques attempt to achieve a recovery time less than 50 ms. In this paper...
We propose a close-to-capacity dirty-paper coding framework which employs multi-level low density parity-check (LDPC) and trellis coded quantization. The proposed coding framework is robust in the sense that it performs close to capacity in the high as well as the low rate regimes. This is in contrast to existing practical DPC schemes which perform well at one of these regimes, but never both. In...
Network coding is known to be a promising technology to increase the bandwidth capacity in wireless networks. To our best knowledge, there is limited work on studying the available bandwidth for a given path with network coding. This paper presents a new method to estimate the available bandwidth of a path that considers network coding and wireless interference simultaneously. We show that our estimated...
This paper investigates the performance of network coding (NC) in unreliable wireless networks and the integration with TCP protocol. As the wireless nodes have limited processing capacity and energy, it will be difficult for them to deal with complex problems. Coding and decoding with traditional NC will cause a large overhead for wireless nodes. It is necessary to improve the NC scheme for applying...
We propose two compute-and-forward coding schemes for the bi-directional relay channel with inter- symbol interference (ISI) based on lattice codes and study their achievable rates. The first coding scheme is similar in spirit to coded orthogonal frequency division multiplexing (OFDM) with independent coding across sub-carriers and uses nested-lattice code with a power allocation strategy that can...
Regenerating codes are a class of codes for distributed storage networks that provide reliability and availability of data, and also perform efficient node repair. Another important aspect of a distributed storage network is its security. In this paper, we consider a threat model where an eavesdropper may gain access to the data stored in a subset of the storage nodes, and possibly also, to the data...
We consider wireless multicasting over lossy links and explore the benefit of cooperative strategies in which multicast receivers exchange messages. A key feature of the problem considered here is that the source downlink channel has a higher loss rate than the channels between pairs of receivers; this feature implies that completion time may be reduced by offloading transmissions to receiver-receiver...
We consider the analysis and design of space-time trellis codes (STTCs) for a cooperative relay channel operating in amplify-and- forward (AF) mode assuming the source and destination nodes are equipped with multiple antennas but the relay node has single antenna. We derive a pairwise error probability (PEP) expression for the performance of STTCs in this type of channels. A simple upper- bound on...
We investigate the error floor performance of Luby Transform (LT) codes over the additive white Gaussian noise channel. We first derive a lower bound on the bit error rate for an LT code, which we subsequently use to show that the corresponding error floor is predominantly caused by low-degree variable nodes. Based on this observation, we propose a modified encoding scheme for LT codes that provides...
Among the "store-carry-forward" kind of protocols, the two-hop relay and its variants have become a class of attractive routing protocols for the mobile ad hoc networks (MANETs) due to its efficiency and simplicity. This paper focuses on the performance modeling for two-hop relay with erasure coding, a promising technique for improving the delay performance of conventional two-hop relay...
This paper investigates the possibility of packet error recovery in a cooperative cluster of mobile devices. We assume that these devices receive data from a broadcast transmission on their primary network interface (e.g. LTE network), and they are using a secondary network interface (e.g. ad hoc WLAN network) to form a cooperative cluster in order to exchange missing data packets among each other...
We show that the performance of relay selection can be improved by employing relays with buffers. Under the idealized assumption that no buffer is full or empty, the best source-relay and the best relay-destination channels can be simultaneously exploited by selecting the corresponding relays for reception and transmission, respectively. The resulting relay selection scheme is referred to as max-max...
This paper presents a new class of rate-compatible LDPC codes, protograph-based Raptor-like (PBRL) codes. The proposed PBRL codes are jointly decodable with an iterative belief propagation decoder. As with Raptor codes, additional parity bits can be easily produced by exclusive-or operations on the precoded bits, providing extensive rate compatibility. This paper provides a design procedure that optimizes...
The broadcast nature of wireless links makes wireless networks an attractive environment for intersession network coding. Most intersession network coding protocols exploit this property, but ignore the diversity among the links by turning off coding when the channels are lossy. Other protocols deal with the packets separately - not as members of flows - which makes the intersession network coding...
In this paper, we propose a Cooperative Differential Space-Time Spreading (CDSTS) scheme employing multiple relays, which eliminates the demanding requirement of channel estimation both at the relays and at the destination. More explicitly, the source node employs differential encoding during the first transmission interval, and the multiple relays perform Differential Space-Time Spreading (DSTS)...
Network coding may improve network efficiency. However, it is not necessary to code every link to meet a given transmission rate. In this paper, we consider the NP-hard problem of minimizing the number of coding links of a network for a given target transmission rate. Chemical Reaction Optimization (CRO) is a general purpose metaheuristic, which have been demonstrated to be effective in many optimization...
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.