Juncheng Jia

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 Clustering Algorithm in Wireless Sensor Networks Using Cooperative Communication

Processing the gathered information efficiently is a key functionality for wireless sensor networks. In generally, the sensor networks often use in-network data aggregation and clustering to optimize network communication. The set of aggregating nodes forms a dominating set of the network graph. Finding the weakly connected dominating set (WCDS) is a promising approach for clustering the WSN. However, finding a minimum WCDS is NP-hard problem for most graphs, and a host of approximation algorithm has been proposed. The aim of the paper is to construct a minimum WCDS as a clustering scheme for WSN. Our clustering schemes construction algorithm includes two phases. First of all, we construct a maximal data aggregation tree (DAT) of the network. The second phase of the algorithm is to choose the nodes (called connectors) to make the WCDS connected. The correctness and performance of our algorithms are confirmed through theoretical analysis and comprehensive simulations.

Cooperative Transmission in Cognitive Radio Ad Hoc Networks

Cognitive radio technology is the key to realize dynamic spectrum access system and promote the spectrum utilization through exploiting the spectrum holes left by primary users. However, the spatial heterogeneity of spectrum availability imposes special challenges for efficient utilization of the spectrum resources for cognitive radio ad hoc networks (CRAHNs). The cross-layer cooperative transmission scheme is a promising approach to improve the efficiency of spectrum utilization and improve the performance of cognitive radio networks. Such an approach leverages relay-assisted discontiguous OFDM (DOFDM) for data transmission at physical and MAC layers in a basic three-node configuration. With this scheme, a relay node will be selected that can bridge the source and the destination using its common channels between those two nodes. In this paper, we investigate the application of such a cooperative transmission scheme to address the spectrum heterogeneity issue in CRAHNs. In particular, we describe several types of cooperative transmission and formulate a new resource allocation problem with joint relay selection and channel allocation. We propose a heuristic algorithm to solve the resource allocation problem, which is based on the metric of utility-spectrum ratio of transmission groups. Simulations demonstrate the performance improvement of the cooperative transmission over the direct transmission.

Congestion Control Based on Consensus in the Wireless Sensor Network

The congestion control algorithm based on the weighted directed graph is designed for the network congestion over the wireless sensor network. The congestion problem is modeled as a distributed dynamic system with time-varying delay, and it can be proven that the sent rate for all nodes converges to the available bandwidth of the sink by the proposed congestion control algorithm. Via Lyapunov function, the validity of the proposed algorithm is shown under the varying network topologies. Ns simulation results indicate that the proposed algorithm restrains the congestion over the wireless sensor network, maintains a high throughput and a low delay time, and also improves the quality of service for the whole network.

A Path Planning Algorithm with a Guaranteed Distance Cost in Wireless Sensor Networks

Navigation with wireless sensor networks (WSNs) is the key to provide an effective path for the mobile node. Without any location information, the path planning algorithm generates a big challenge. Many algorithms provided efficient paths based on tracking sensor nodes which forms a competitive method. However, most previous works have overlooked the distance cost of the path. In this paper, the problem is how to obtain a path with minimum distance cost and effectively organize the network to ensure the availability of this path. We first present a distributed algorithm to construct a path planning infrastructure by uniting the neighbors’ information of each sensor node into an improved connected dominating set. Then, a path planning algorithm is proposed which could produce a path with its length at most c times the shortest Euclidean length from initial position to destination. We prove that the distributed algorithm has low time and message complexity and c is no more than a constant. Under different deployed environments, extensive simulations evaluate the effectiveness of our work. The results show that factor c is within the upper bound proved in this paper and our distributed algorithm achieves a smaller infrastructure size.

A cost-effective scheme for restoring connectivity of disconnected WSNs

Many works on restoring WSN connectivity pursue complete recovery of the original connectivity. Doing so would inevitably incur high time complexity and large number of restoration nodes. However, for many applications, 100% recovery of the original connectivity is not necessary. We propose a scheme for deploying restoration sensors for a disconnected WSN to reconnect the network, achieving remarkable restored connectivity while keeping the number of restoration nodes at a low level. Since an accurate, optimal solution to the problem is NP-hard, we resort to tackling the problem in a greedy and heuristic manner. Analysis and performance evaluation via simulation show that the proposed scheme can restore the networks connectivity to a very good level with relatively low cost in terms of algorithm time and restoration nodes needed.

Joint Selection of Providers and the New Comer for Optimal Repair in Distributed Storage Network with Network Coding

In distributed storage networks (DSN), server failures occur frequently. Although network coding can provide high reliability of storage in DSN, to maintain reliability, a new server, named the new comer, should be firstly implemented to replace the failed server. Then, new comer should download enough data from multiple storage servers, called provider selected from surviving servers to regenerate the lost data. Therefore, the providers, new comer and data routing have a great impact on regeneration time during repair process. In this paper, we jointly consider the providers and new comer selection (JPNS) problem with two objectives of minimizing regeneration time and minimizing transmission cost under the minimum regeneration time guarantee. Specifically, for the first objective, we firstly model the JPNS problem as a mathematical programming and formulate it as an integer linear programming (ILP). We also propose a Heuristic Providers and New Comer Selection (HPNS) algorithm. For the second objective, based on the providers and a new comer selected by the HPNS algorithm, we give a linear programming (LP) to optimally obtain the routing paths and flows from these providers to the new comer with minimum transmission cost. Finally, we conduct extensive simulation experiments and the results show the effectiveness of the proposed algorithms.

Resilient Multipath Routing Mechanism Based on Clustering with Intrusion Tolerance

Wireless sensor networks (WSNs) integrate sensor technology, communication technology and information processing technology; it is a synthetic discipline. WSNs have been applied into almost all walks of life. However, in many special fields, network security is a basic and important factor which we must concern for. This paper introduces the key management scheme after analyzing the security threats of LEACH protocol. At the same time, we adopt several related mechanisms to protect the communication among the sensor nodes and the confidentiality of the data transmission. Also, we use the mixed multipath mechanism among the clusters to improve the security of the network and strengthen the intrusion tolerance.