Yanqin Zhu

An Efficient Reliable Communication Scheme in Wireless Sensor Networks Using Linear Network Coding

We address the modeling and design of linear network coding (LNC) for reliable communication against multiple failures in wireless sensor networks (WSNs). To fulfill the objective, we design a deterministic LNC scheme RDLC based on the average number of path failures simultaneously happening in the network other than the maximum number of path failures. The scheme can significantly improve the network throughput comparing with the traditional approaches. In our study, we also investigate the potential of random linear code RRLC for providing reliable communication in WSNs and prove the low bound of the probability that the RRLC can provide the reliable communication. Finally, extensive simulation experiments have been conducted, and the results demonstrate the effectiveness of the proposed LNC schemes.

An efficient communication relay placement algorithm for content-centric wireless mesh networks

In this paper, we investigate a communication relay placement problem to optimize the network throughput in a content-centric wireless mesh networks WMN, in which the WMN is enhanced by including a small set of communication relays and a subset of wireless mesh routers serving as storage nodes. Specifically, we first define the communication relay placement problem in content-centric WMNs. We then model the problem as a mathematical programming and propose a linear programming approach for calculating the achievable network throughput when the positions of communication relays are fixed. Next, to optimally placing the communication relays, we formulate an integer linear programming problem and we develop an efficient near-optimal approximation algorithm based on linear programming relaxation. Finally, extensive simulation experiments have been conducted, and the results demonstrate the effectiveness of the proposed algorithms. Copyright

How Much Delay Has to Be Tolerated in a Mobile Social Network

Message delivery in a mobile social network (MSN) is difficult due to the fact that the topology of such network is sparse and unstable. Various routing schemes for MSNs were proposed to make the message delivery robust and efficient. However, little research has been conducted to explore how much delay has to be tolerated for the message delivery from the source to the destination. Since the social relationships among nodes are stable during a certain period of time, it is expected that the delay of message delivery in MSNs could be modeled with a probability model. In this paper, we take the first step to address this issue. We firstly extract three routing models from the existing routing schemes for MSNs and then develop the probability models of the message transmission delay for each abstract routing model. The simulation results show that the theoretical models match very well the simulation trace statistics.

Data Dissemination in Mobile Wireless Sensor Network Using Trajectory-Based Network Coding

With GPS devices spreading, more mobile nodes are guided by the navigation systems to select better paths. The performance of mobile networks can be improved with the navigation information in nodes. In this paper, we propose a trajectory-based network coding (TBNC) method to disseminate data in mobile wireless sensor network (MWSN). It is designed according to the characteristics of MWSN and is appropriate for the mobile nodes that share anonymously its GPS pretrajectory for the higher bandwidth. Data are disseminated in the topology that is predicted on the basis of the trajectory information. Network coding is used to adapt for the dynamics velocity of mobile nodes. Simulation results show that TBNC is able to cut down 1/2 overhead messages of PRoPHET when mobile nodes share GPS trajectory. It improves the reliability and scalability of MWSN.

Network coding-based real-time retransmission scheme in wireless sensor networks

In wireless sensor networks (WSNs), wireless links are unreliable and sensor nodes may be in sleep mode. Thus, many applications which require reliable broadcast cannot work properly if they lost some packets. In order to make sure every sensor node in the network receives all packets completely and correctly, retransmission of lost packets is indispensable. Many retransmission methods with network coding have been proposed but they do not catch coding opportunity. In this paper, real-time retransmission algorithm based on network coding (NCRR) is proposed to make the average number of transmissions as less as possible. During the transmission of original packets, we detect whether a certain time slot is suitable for retransmitting a coded packet based on recovery ratio. We analyze the number of transmissions with traditional retransmission and with network coding. Compared with existing approaches, simulation results show that our algorithm can effectively reduce the average number of transmissions and improve the transmission efficiency.

SNKC: An Efficient On-the-Fly Pollution Detection Scheme for Content Distribution with Network Coding

Linear network coding (LNC) has attracted significant attention because it has the potential to achieve the throughput capacity of a network. However, transmission systems with LNC are vulnerable to pollution attacks in which normal packets will be corrupted by malicious relay nodes and participate in normal encoding process. The null keys based error detection schemes have been designed to efficiently defend against the pollution attacks, in which null keys is a set of vectors sent from source to relay nodes to verify the correctness of the coded packets. However, the existing Null Key based schemes either cannot efficiently distribute the null keys in large scale networks or defend against collusion attacks. In this paper, we design a Short Null Keys Compression (SNKC) scheme. It is designed to reduce the required amount of null keys distributed by the source, so as to defend against collusion attacks efficiently. Specifically, through the design of SNKC scheme, the size of linear space spanned by all null keys will be significantly reduced.

Optimal Flow Allocation and Linear Network Coding Design for Multiple Multicasts under the Requirements of Information Theoretical Security

Linear network coding (LNC) has great advantages in optimizing throughput, balancing network load, increasing robustness, etc. Since the coded data packets transmitted in the network are linear combinations of original data packets, the attacker cannot decode to obtain the original data when it cannot acquire enough coded data packets. Therefore, LNC can also provide efficient information security against various attacks in a communication network when not using the secret key to encrypt and decrypt. In this paper, we will study the flow allocation and LNC design for multiple multicasts to maximize the secure transmission rate (STR) and minimize the bandwidth cost (BC) under the requirements of information theoretical security (ITS), which is referred to as the Information Theoretically Secure Multiple Multicasts (ITSMM) problem. Firstly, we analyze the ITSMM problem theoretically and prove that it can be transformed to a constrained maximum network flow problem. Then, based on the theoretical analysis, we model the ITSMM problem as two linear programming (LP) formulations, which can firstly obtain the maximum STR, and then find the optimal flow allocation to minimize total BC under the maximum STR guarantee. Finally, we conduct extensive simulations and show the effectiveness of the proposed algorithm.

Optimal Rate Allocation and Linear Network Coding Design for Secure Multicast with Multiple Streams

Recently, network traffic keeps growing rapidly. How to efficiently and securely deliver huge volume of data to multiple devices is a challenging problem. Linear network coding (LNC) is a technique which can be used to improve network throughput, efficiency and security. In this paper, we investigate the secure multicast with multiple streams (SMMS) problem. Specifically, we jointly consider the rate allocation, the transmission topology selection and the secure LNC design together to maximize the secure weighted throughput (SWT) of the multicast. We first define the SMMS problem and theoretically prove a sufficient and necessary condition that a secure multicast LNC exists. Moreover, we also show the construction of the secure multicast LNC and the sufficient condition on the size of the required finite field. We then model the SMMS problem as a nonlinear programming (NLP) and further equivalently transform it as a linear programming (LP) to find the optimal rate allocation and transmission topology based on which a secure multicast LNC exists to achieve the maximum SWT. Finally, we conduct considerable simulations with different parameters to demonstrate the effectiveness of the proposed schemes.

Network coding with crowdsourcing-based trajectory estimation for vehicular networks

It is a great challenge to transmit data in vehicular networks, where the link among nodes is very shaky because of the rapid movement of vehicles. In this paper, we propose a Network Coding with Crowdsourcing-based Trajectory Estimation (NC/CTE) method to transmit data in vehicular networks. Key points are designated beforehand in movement area. Every node estimates which of Key points the other nodes in the discovered area close to at the different times. The estimation is completed by every node in crowdsourcing method based on the pre-trajectory of GPS navigation. Network coding, recoding and reverse forwarding are used for data transmission according to the result of trajectory estimation. Simulation results show that NC/CTE is able to cut down 1/2 overhead messages of TBNC when mobile nodes have shared their GPS trajectories. It improves the reliability and scalability of vehicular networks. �

On the Optimal Provider Selection for Repair in Distributed Storage System with Network Coding

In large-scale distributed storage systems (DSS), reliability is provided by redundancy spread over storage servers across the Internet. Network coding (NC) has been widely studied in DSS because it can improve the reliability with low repair time. To maintain reliability, an unavailable storage server should be firstly replaced by a new server, named new comer. Then, multiple storage servers, called providers, should be selected from surviving servers and send their coded data through the Internet to the new comer for regenerating the lost data. Therefore, in a large-scale DSS, provider selection and data routing during the regeneration phase have great impact on the performance of regeneration time. In this paper, we investigate a problem of optimal provider selection and data routing for minimizing the regeneration time in the DSS with NC. Specifically, we first define the problem in the DSS with NC. For the case that the providers are given, we model the problem as a mathematical programming. Based on the mathematical programming, we then formulate the optimal provider selection and data routing problem as an integer linear programming problem and develop an efficient near-optimal algorithm based on linear programming relaxation (BLP). Finally, extensive simulation experiments have been conducted, and the results show the effectiveness of the proposed algorithm.