Virtual Grid Architecture Research Articles

FTGAF-HEX: fuzzy logic based two-level geographic routing protocol in wireless sensor networks

Minimization of energy consumption has become a major challenge in wireless sensor networks (WSNs) as it directly corresponds to the network lifetime. In WSNs, geographic adaptive fidelity (GAF) is one of the most energy efficient location based protocol which extends the network lifetime by identifying equivalence between sensors using geographic location information and then keeping unnecessary sensors in sleep state, while maintaining application fidelity. Still traditional GAF cannot reach to the optimum energy usage since it needs more hop count to transmit data packets to the base station called sink. As a result, it leads to higher energy usage and packet delay due to participation of more sensors. In this paper, a fuzzy logic based topology management protocol named FTGAF-HEX, which bases on GAF is proposed to achieve minimum packet delay with higher energy conservation. Furthermore, we propose to use a generalized version of GAF based on honeycomb virtual grid architecture called Hexagonal GAF (GAF-HEX) to replace the square grid with hexagonal one. Analysis and simulation results show significant improvement of the proposed work compared to traditional GAF in the aspect of various performance metrics i.e., total hop count, energy consumption and distance covered by the data packet before reaching the sink. As a result, compared to traditional GAF-HEX, it needs 37–44% less hop count and consumes 17–24% less energy to prolong the network lifetime.

Comparison of Energy Efficient Data Transmission Approaches for Flat Wireless Sensor Networks

In this paper we have analyzed energy efficient neighbour selection algorithms for routing in wireless sensor networks. Since energy saving or consumption is an important aspect of wireless sensor networks, its precise usage is highly desirable both for the faithful performance of network and to increase the network life time. For this work, we have considered a flat network topology where every node has the same responsibility and capability. We have compared two energy efficient algorithms and analyzed their performances when all sensor nodes in a network have either homogeneous or heterogeneous energy with increase in number of nodes, time rounds and node failures. Wireless sensor networks consist of number of small nodes deployed in an area under supervision. Each node has limited storage, computational and sensing capability and limited energy resource, as nodes are battery operated. Since energy is the main concern in wireless sensor networks (WSN) to maximize the performance and to increase the lifetime of a network, various approaches are implemented to reduce energy consumption in a network. Most of the energy is consumed during idle period and during transmission of data from one node to another i.e. routing. An efficient media access control (MAC) and routing protocol should be designed to save energy. While MAC protocol targets at reduction of energy in scanning and accessing the channel, routing protocol helps to reduce the energy requirement for end-to-end transmission. In WSN, there are number of routing protocols that have been proposed for different network criteria. Based on the network topology WSN protocols have been categorized as - flat network protocols and hierarchical protocols as shown in Figure 1. Protocols that fall under hierarchical class select one head amongst all and form a hierarchy (1). This hierarchy may be a cluster, a chain or a grid. Cluster head or a leader collects the information from all the other nodes in its region and sends it to the sink node or gateway node. Some examples are low energy adaptive clustering hierarchy (LEACH), power efficient gathering in sensor information systems (PEGASIS), virtual grid architecture (VGA), etc. The work presented in this paper considers flat protocols and thus we are not including descriptions of hierarchical protocols and will only be

Parameterized Affect of Transmission-Range on Lost of Network Connectivity (LNC) of Wireless Sensor Networks

Wireless Sensor Networks, referred to as WSNs, are made up of various types of sensor nodes. Recent developments in micro electro-mechanical technology have given rise to new integrated circuitry, microprocessor hardware and nano technology, wireless technology, and advanced networking routing protocols. Hospitals and health service facilities, the armed forces, and even residential customers represent a potential huge market for these devices. The problem is that existing sensor network nodes are incapable of providing the support needed to maximize usage of wireless technology. For this reason, there are many novel routing protocols for the wireless sensor networks proposed recently. One is Hierarchical or cluster-based routing. In this paper, we analyze three different types of hierarchical routing protocols: Low Energy Adaptive Clustering Hierarchy (LEACH), Power-Efficient Gathering in Sensor Information Systems (PEGASIS), and Virtual Grid Architecture (VGA). We tried to analyze the performance of these protocols, including the power consumption and overall network performance. We also compared the routing protocol together. This comparison reveals the important features that need to be taken into consideration while designing and evaluating new routing protocols for sensor networks. The simulation results, using same limited sensing range value, show that PEGASIS outperforms all other protocols while LEACH has better performance than VGA. Furthermore, the paper investigates the power consumption for all protocols. On the average, VGA has the worst power consumption when the sensing range is limited, while VGA is the best when the sensing range is increased. Using homogeneous nodes can greatly prolong sensor network’s life time. Also, The network lifetime increases as the number of clusters decreases

Efficient virtual-backbone routing in mobile ad hoc networks

Since the physical topology of mobile ad hoc networks (MANETs) is generally unstable, an appealing approach is the construction of a stable and robust virtual topology or backbone. A virtual backbone can play important roles related to routing and connectivity management. In this paper, the problem of providing such a virtual backbone with low overhead is investigated. In particular, we propose an approach, called virtual grid architecture (VGA), that can be applied to both homogeneous and heterogeneous MANETs. We study the performance tradeoffs between the VGA clustering approach and an optimal clustering based on an integer linear program (ILP) formulation. Many properties of the VGA clustering approach, e.g., VGA size, route length over VGA, and clustering overhead are also studied and quantified. Analytical as well as simulation results show that average route length over VGA and VGA cardinality tend to be close to optimal. The results also show that the overhead of creating and maintaining VGA is greatly reduced, and thus the routing performance is improved significantly. To illustrate, two hierarchical routing techniques that operate on top of VGA are presented and evaluated. Performance evaluation shows that VGA clustering approach, albeit simple, is able to provide more stable (long lifetime) routes, deliver more packets, and accept more calls.

End-to-end support for statistical quality of service in heterogeneous mobile ad hoc networks

In heterogeneous mobile ad hoc networks (MANETs), different types of mobile devices with diverse capabilities may coexist in the same network. The heterogeneity of MANETs makes end-to-end support for quality of service (QoS) guarantees more difficult than in other types of networks, not to mention the limited bandwidth and frequent topology changes of these networks. Since QoS routing is the first step toward achieving end-to-end QoS guarantees in heterogeneous MANETs, we propose a QoS routing protocol for heterogeneous MANETs. The proposed protocol, called virtual grid architecture protocol (VGAP), uses a cross-layer approach in order to provide end-to-end statistical QoS guarantees. VGAP operates on a fixed virtual rectilinear architecture (virtual grid), which is obtained using location information obtained from global positioning system (GPS). The virtual grid consists of a few, but possibly more powerful, mobile nodes known as ClusterHeads (CHs) that are elected periodically. CHs discover multiple QoS routes on the virtual grid using an extended version of the open shortest path first (OSPF) routing protocol and an extended version of WFQ scheduling policy that takes into account the wireless channel state. Moreover, VGAP utilizes a simple power control algorithm at the physical layer that provides efficient energy savings in this heterogeneous setting. Simulation experiments show that VGAP has a good performance in terms of packet delivery ratio, end-to-end packet delay, call blocking probability, and network scalability.

Mapping uniform loop nests onto distributed memory architectures

This paper deals with scheduling, mapping and partitioning techniques for uniform loop nests. Target machines are SPMD distributed memory parallel computers. We use affine-by-statement scheduling and affine-by-variable mapping to synthesize a virtual grid architecture from the original loop nest. The virtual grid architecture is then partitioned into a physical processor grid. The key to the mapping strategy is the communication graph, which enables us to derive optimal mappings, i.e. where the number of communications is proved to be minimal. The partitioning technique extends the methods developed for systolic array design methodologies to loop nests with several statements.