The goal of this paper is two-fold. First, to expand an opportunistic network coding protocol for wireless networks, called PlayNCool, in order to incorporate new mechanisms to improve performance in the presence of p...
详细信息
ISBN:
(纸本)9781509059324
The goal of this paper is two-fold. First, to expand an opportunistic network coding protocol for wireless networks, called PlayNCool, in order to incorporate new mechanisms to improve performance in the presence of packet losses. In particular, exploiting additional helper nodes to improve the quality of each link and even across neighbouring links and using simulations to show that an additional reduction of packet transmission in the order of 40% is possible. Second, to advocate for the use of network coding (NC) jointly with software defined networking (SDN) providing an implementation of the expanded PlayNCool protocol using SDN. This implementation uses an architecture developed with OpenFlow switches and a Pox controller to periodically gather statistics related to packet losses and the number of packets coded, recoded and decoded on a per link basis in order to adapt the configuration for the PlayNCool protocol optimally. The measurements carried out were validated with theoretical and simulated results.
Recently, Wang and Chen [1] showed that network coding (NC) can double the throughput as compared to routing in delay-constrained single-unicast communication. This is in sharp contrast to its delay-unconstrained coun...
详细信息
ISBN:
(纸本)9781509018079
Recently, Wang and Chen [1] showed that network coding (NC) can double the throughput as compared to routing in delay-constrained single-unicast communication. This is in sharp contrast to its delay-unconstrained counterpart where coding has no throughput gain. The result reveals that the landscape of delay-constrained communication is fundamentally different from the well-understood delay-unconstrained one and calls for investigation participation. In this paper, we generalize the Koetter-Medard algebraic approach [2] for delay-unconstrained network coding to the delay-constrained setting. The generalized approach allows us to systematically model deadline-induced interference, which is the unique challenge in studying network coding for delay-constrained communication. Using this algebraic approach, we characterize the coding capacity for single-source unicast and multicast, as the rank difference between an information space and a deadline-induced interference space. The results allow us to numerically compute the NC capacity for any given graph, serving as a benchmark for existing and future solutions on improving delay-constrained throughput.
Reliability is an important issue in wireless sensor networks (WSNs). Reliable transmission of data in WSNs is the basic of successful network operation. In this paper, we firstly define the evaluation methods for rel...
详细信息
ISBN:
(数字)9783319607177
ISBN:
(纸本)9783319607177;9783319607160
Reliability is an important issue in wireless sensor networks (WSNs). Reliable transmission of data in WSNs is the basic of successful network operation. In this paper, we firstly define the evaluation methods for reliability in WSNs in terms of evaluation metrics and recovery ways. The technologies to improve reliability for WSNs are summed up in several classifications: retransmission, redundancy, hybrid method and some newly emerging technologies. Some typical protocols are stated and analyzed. Also we compare these technologies in several aspects as the direction for future research.
This paper studies the problem of offloading the fronthaul of Fog Radio Access networks (F-RANs) with smart user equipments (denoted by F-UEs) that can cache files and cooperate with each other to retrieve their reque...
详细信息
ISBN:
(纸本)9781509050192
This paper studies the problem of offloading the fronthaul of Fog Radio Access networks (F-RANs) with smart user equipments (denoted by F-UEs) that can cache files and cooperate with each other to retrieve their requested files. This cooperation between the F-UE devices will reduce the load on the fronthaul of the central baseband processing unit (BBU), thus increasing the overall capacity of the network. By smartly employing network coding (NC), this paper aims to minimize the number of transmissions required from the BBU given a realistic half-duplex transmission scenario. In this setting, F-UE devices can only send or receive at a time, and thus must receive their requested files in maximum two time-slots in order to achieve high quality of experience (QoE). The above problem is first formulated over an NC graph. Being NP-hard, two heuristic algorithms are proposed to solve the problem in real-time. Simulation results show that these proposed heuristics perform closely to the optimal solution. They also demonstrate the significant fronthaul offloading gains achieved by our proposed algorithms.
Oblivious RAM (ORAM) is a primitive for hiding storage access patterns in the context of software protection. With the trend of cloud computing, ORAM also has important applications in privacy-preserving cloud storage...
详细信息
ISBN:
(纸本)9781509056521
Oblivious RAM (ORAM) is a primitive for hiding storage access patterns in the context of software protection. With the trend of cloud computing, ORAM also has important applications in privacy-preserving cloud storage applications. Many ORAMs for cloud storage have been proposed to improve efficiency and security. However, data availability, data confidentiality, and data integrity have not been simultaneously addressed. In this paper, we formalize a new concept of ORAM called RORAM (Robust ORAM by enhancing availability, confidentiality and integrity), which can deal with these three challenges. Furthermore, RORAM not only can achieve a higher security level but also is more efficient compared with previous ORAMs by using linear network coding to reduce the client's computational cost of block encryption/decryption in every read/write operation in previous ORAMs. The security and complexity analyses show that RORAM is provably secure and highly lightweight.
In this study, the error performance analysis of decode and forward (DF) based multiple access relay channel (MARC) system model is investigated for binary phase shift keying (BPSK) modulation when there is co-channel...
详细信息
ISBN:
(纸本)9781509064946
In this study, the error performance analysis of decode and forward (DF) based multiple access relay channel (MARC) system model is investigated for binary phase shift keying (BPSK) modulation when there is co-channel interference effects at relay node and maximum likelihood (ML) approach is used at destination node. MARC system model is one of the important network coding applications in wireless cooperative communication. The simulation results show that MARC system model provides full diversity gain for BPSK modulation.
We state and solve a problem of the optimal geographic caching of content in cellular networks, where linear combinations of contents are stored in the caches of base stations. We consider a general content popularity...
详细信息
ISBN:
(纸本)9783901882906
We state and solve a problem of the optimal geographic caching of content in cellular networks, where linear combinations of contents are stored in the caches of base stations. We consider a general content popularity distribution and a general distribution of the number of stations covering the typical location in the network. We are looking for a policy of content caching maximizing the probability of serving the typical content request from the caches of covering stations. The problem has a special form of monotone sub-modular set function maximization. Using dynamic programming, we find a deterministic policy solving the problem. We also consider two natural greedy caching policies. We evaluate our policies considering two popular stochastic geometric coverage models: the Boolean one and the Signal-to-Interference-and-Noise-Ratio one, assuming Zipf popularity distribution. Our numerical results show that the proposed deterministic policies are in general not worse than some randomized policy considered in the literature and can further improve the total hit probability in the moderately high coverage regime.
The distributed storage system maintains the data at multiple nodes in the network to provide faster access to data. In case of failure of one node the data is made available to the users from other nodes and the lost...
详细信息
ISBN:
(纸本)9781509035199
The distributed storage system maintains the data at multiple nodes in the network to provide faster access to data. In case of failure of one node the data is made available to the users from other nodes and the lost data can be recovered from the surviving nodes. network coding plays an important role in managing the distributed data. Various coding mechanism like Replication, Erasure coding, Local Reconstruction, Regeneration, Hybrid and Double coding have been found beneficial for distributed storage systems. The parameters that make these approaches different from each other are storage requirement, repair bandwidth, node access, fault tolerance etc. This paper proposes a new approach that is capable of repairing the damages with minimum repair bandwidth and occupies less storage compared to other related approaches.
The interest in subspace codes has increased in recent years due to their application in error correction for random network coding. In order to study their properties and find good constructions, the notion of cyclic...
详细信息
ISBN:
(纸本)9781509040964
The interest in subspace codes has increased in recent years due to their application in error correction for random network coding. In order to study their properties and find good constructions, the notion of cyclic subspace codes was introduced by using the extension field structure of the ambient space. However, to this date there exists no general construction with a polynomial relation between k, the dimension of the codewords, and n, the dimension of the entire space. Independently of the study of cyclic subspace codes, Sidon spaces were recently introduced by Bachoc et al. as a tool for the study of certain multiplicative properties of subspaces over finite fields. In this paper it is shown that Sidon spaces are necessary and sufficient for obtaining a full-orbit cyclic subspace code with minimum distance 2k - 2. By presenting several constructions of Sidon spaces, full-orbit cyclic subspace codes are obtained, in which n is quadratic in k. The constructions are based on a variety of tools;namely, Sidon sets, that are sets of integers in which all pairwise sums are distinct, irreducible polynomials, and linearized polynomials. Further, the existence of a Sidon space in which n is linear in k is shown, alongside the fact that any Sidon space induces a Sidon set.
Content delivery network (CDN) allows internet providers to locate their services, to map their coverage into networks without necessarily to own them. CDN is part of the current internet infrastructures, supporting m...
详细信息
Content delivery network (CDN) allows internet providers to locate their services, to map their coverage into networks without necessarily to own them. CDN is part of the current internet infrastructures, supporting multi server applications especially social media. Various works have been proposed to improve CDN performances. Since accesses on social media servers tend to be short but frequent, providing redundant to the transmitted packets to ensure lost packets not degrade the information integrity may improve service performances. This paper examines the implementation of rateless code in the CDN infrastructure. The NS-2 evaluations show that rateless code is able to reduce packet loss up to 50%.
暂无评论