Reach Centroid Localization Algorithm

As much as accurate or precise position estimation is always desirable, coarse accuracy due to sensor node localization is often sufficient. For such level of accuracy, Range-free localization techniques are being explored as low cost alternatives to range based localization techniques. To manage cost, few location aware nodes, called anchors are deployed in the wireless sensor environment. It is from these anchors that all other free nodes are expected to estimate their own positions. This paper therefore, takes a look at some of the foremost Range-free localization algorithms, detailing their limitations, with a view to proposing a modified form of Centroid Localization Algorithm called Reach Centroid Localization Algorithm. The algorithm employs a form of anchor nodes position validation mechanism by looking at the consistency in the quality of Received Signal Strength. Each anchor within the vicinity of a free node seeks to validate the actual position or proximity of other anchors within its vicinity using received signal strength. This process mitigates multipath effects of radio waves, particularly in an enclosed environment, and consequently limits localization estimation errors and uncertainties. Centroid Localization Algorithm is then used to estimate the location of a node using the anchors selected through the validation mechanism. Our approach to localization becomes more significant, particularly in indoor environments, where radio signal signatures are inconsistent or outrightly unreliable. Simulated results show a significant improvement in localization accuracy when compared with the original Centroid Localization Algorithm, Approximate Point in Triangulation and DV-Hop.

Comparison of Indoor Localization Systems Based on Wireless Communications

Localization using a Wireless Sensor Network (WSN) has become a field of interest for researchers in the past years. This information is expected to aid in routing, systems maintenance and health monitoring. For example, many projects aiming to monitor the elderly at home include a personal area network (PAN) which can provide current location of the patient to the medical staff. This article presents an overview of the current trends in this domain. We introduce the mathematical tools used to determine position then we introduce a selection of range-free and range-based proposals. Finally, we provide a comparison of these techniques and suggest possible areas of improvement.

Cooperative Nodes Localization for Three-Dimensional Underwater Wireless Sensor Network Based on Weighted Centroid Localization Algorithm

The underwater wireless sensor network(UWSN) has the features of mobility by drifting,less beacon nodes,longer time for localization and more energy consumption than the terrestrial sensor networks,which makes it more difficult to locate the nodes in marine environment.Aiming at the characteristics of UWSN,a kind of cooperative range-free localization method based on weighted centroid localization(WCL) algorithm for three-dimensional UWSN is proposed.The algorithm assigns the cooperative weights for the beacon nodes according to the received acoustic signal strength,and uses the located unknown nodes as the new beacon nodes to locate the other unknown nodes,so a fast localization can be achieved for the whole sensor networks.Simulation results indicate this method has higher localization accuracy than the centroid localization algorithm,and it needs less beacon nodes and achieves higher rate of effective localization.

A Novel Multi-Hop Algorithm for Wireless Network with Unevenly Distributed Nodes

Node location estimation is not only the promise of the wireless network for target recognition,monitoring,tracking and many other applications,but also one of the hot topics in wireless network research.In this paper,the localization algorithm for wireless network with unevenly distributed nodes is discussed,and a novel multi-hop localization algorithm based on Elastic Net is proposed.The proposed approach is formulated as a regression problem,which is solved by Elastic Net.Unlike other previous localization approaches,the proposed approach overcomes the shortcomings of traditional approaches assume that nodes are distributed in regular areas without holes or obstacles,therefore has a strong adaptability to the complex deployment environment.The proposed approach consists of three steps:the data collection step,mapping model building step,and location estimation step.In the data collection step,training information among anchor nodes of the given network is collected.In mapping model building step,the mapping model among the hop-counts and the Euclidean distances between anchor nodes is constructed using Elastic Net.In location estimation step,each normal node finds its exact location in a distributed manner.Realistic scenario experiments and simulation experiments do exhibit the excellent and robust location estimation performance.

Location-aided and secure routing protocol for heterogeneous multi-hop wireless networks

Most of the existing routing protocols for heterogeneous multi-hop wireless networks （HWMNs） use on-demand routing protocols owing to their suitability for dynamic topology environments, but it causes wastes of network resources with large number of data packets being broadcast. Furthermore, some nodes in heterogeneous wireless multi-hop networksmay be malicious or selfish nodes which can easily lead to link attacks. A novel routing protocol called trust-based secure routing protocol with auxiliary of nodes＇ location information （TSRAL） is proposed for the establishment of a secure routing protocol with a lower overhead for HWMNs which combines the location information and trust value of nodes to select the next forwarding nodes. The destination node selects an optimal path from multiple paths according to the total trust value and the hop number of routes. Simulation results demonstrate that TSRAL can not only reduce the number of hops and data packets being broadcast in the process of routing but also ensure the safety of the route.