Minimum Hop Count Research Articles

A Context-Aware M2M-Based Middleware for Service Selection in Mobile Ad-Hoc Networks

This paper proposes a novel middleware for service selection in mobile ad-hoc networks with a particular focus on scenarios immediately and subsequently afterwards an emergency. The proposed middleware, operating on a mobile user’s hand-held device and collecting the user’s contexts through machine-to-machine connectivity, has three major contributions as compared to the current literature. The middleware, based on the collected contexts, firstly classifies a service request, e.g., safety-related or comfort service. Then, it initiates the required network connectivity for service discovery, i.e., the ad-hoc connectivity when an infrastructure-based network is inaccessible. Finally, the middleware selects the service based on a method specifically proposed for that service category, including pre-defined realistic user contexts, to access it. The simulation results show that the middleware achieves up to 12 percent higher success rate compared to the minimum hop count service selection method. Compared with the same method, it has a response time up to 50 percent lower for the safety-related but 80 percent higher for the comfort services. Yet, the middleware attains up to 96 percent user satisfaction rate for both service classes.

Nexthop selection mechanism for nodes with heterogeneous transmission range in VANETs

The frequent relocating of vehicles will significantly degrade the routing performance of a VANET. One of the proposed routing approaches to relieve this drawback adopts a greedy fashion to relay the packets hop-by-hop by selecting the nearest neighboring vehicle to the destination as the nexthop forwarder. It is an efficient method of packet routing when the transmission range of each vehicle in the VANET is of the same fixed length. Recently, as heterogeneous wireless networks have become popular, wireless terminals are generally equipped with multiple wireless access network interfaces to improve the quality of transmission and to gain a good signal while relocating. However, the greedy approach of nexthop forwarder selection will not always use the minimum hop counts of the routing path for VANET heterogeneous transmission range nodes. In this paper, we propose a nexthop selection mechanism for VANETs which takes the heterogeneous environment into consideration. A minimum hop count prediction method is firstly proposed to help the current packet-carrying vehicle node to estimate the minimum hop counts required from each neighbor to the destination. Subsequently, based on the estimated values, the routing decision can be made. The simulation results show that our proposed method exhibits better performance in terms of the average end-to-end delay and the packet delivery ratio comparisons than the compared methods.

An Energy Efficient Routing Protocol for Wireless Sensor Networks using A-star Algorithm

Sensors are regarded as significant components of electronic devices. In most applications of wireless sensornetworks (WSNs), important and critical information must be delivered to the sink in a multi-hop and energy-efficientmanner. Inasmuch as the energy of sensor nodes is limited, prolonging network lifetime in WSNs is considered to bea critical issue. In order to extend the network lifetime, researchers should consider energy consumption in routingprotocols of WSNs. In this paper, a new energy-efficient routing protocol (EERP) has been proposed for WSNs usingA-star algorithm. The proposed routing scheme improves the network lifetime by forwarding data packets via theoptimal shortest path. The optimal path can be discovered with regard to the maximum residual energy of the nexthop sensor node, high link quality, buffer occupancy and minimum hop counts. Simulation results indicate that theproposed scheme improves network lifetime in comparison with A-star and fuzzy logic(A&F) protocol.

A Cross-Layer Delay-Aware Node Disjoint Multipath Routing Algorithm for Mobile Ad Hoc Networks

Future mobile Ad hoc networks (MANETs) are expected to be based on all-IP architecture and be capable of carrying multitudinous real-time multimedia applications such as voice, video and data. It is very necessary for MANETs to have a reliable and efficient routing and quality of service (QoS) mechanism to support diverse applications which have variances and stringent requirements for delay, jitter, bandwidth, packet loss. Routing protocols such as AODV, AOMDV, DSR and OLSR use shortest path with the minimum hop count as the main metric for path selection, hence are not suitable for delay sensitive real time applications. To support such applications delay constrained routing protocols are employed. These Protocols makes path selection between source and destination based on the delay over the discovered links during routing discovery and routing table calculations. We propose a variation of a node-disjoint Multipath QoS Routing protocol called Cross Layer Delay aware Node Disjoint Multipath AODV (CLDMAODV) based on delay constraint. It employs cross-layer communications between MAC and routing layers to achieve link and channel-awareness. It regularly updates the path status in terms of lowest delay incurred at each intermediate node. The performance of the proposed protocol is compared with single path AODV and NDMR protocols. Proposed CLDM-AODV is superior in terms of better packet delivery and reduced overhead between intermediate nodes.

Energy Conscious Routing in MANET

The Mobile ad hoc network (MANET) are infrastructure-less, self-organizing, rapidly deployable wireless networks, they are highly suitable for applications involving special outdoor events, communications in regions with no wireless infrastructure, emergencies and natural disasters, and military operations. Routing is one of the key issues in MANETs due to their highly dynamic and distributed nature. In particular, energy efficient routing is the most important design criteria for MANETs since mobile nodes will be powered by batteries with limited capacity. The routing mechanism is based on minimum hop counts, the distance between each pair of nodes becomes larger and hence higher transmission power is required for the communication. Power failure of a mobile node not only affect the node itself but also its ability to forward packets on behalf of others and thus the overall network lifetime. The low residual energy might be one of the reasons of route breakage. Also the mobility of nodes makes link failure and retransmission of packet. In this paper we have modified the Energy Conscious DSR protocol which has basic protocol Dynamic Source routing (DSR). The paper focuses on the mobility of nodes, low residual energy which is the cause of route breakage and packet retransmission, which get solved and communication is keep going without any interruption and the network lifetime increases. We have validated our proposed protocol through ns-2.34 and evaluated the performance of the networks by considering few energy metrics. We got the results as our modified ECDSR outperforms DSR and Ad-Hoc on demand Distance Vector (AODV) in performance analysis.

Energy efficient network protocol architecture for narrowband power line communication networks

This paper presents newly researched and developed network layer protocol for narrowband power line communication (PLC) within the last mile of advanced metering management systems. This communication medium is known for its low data rates and issues with signal propagation and noise inherence. After the network properties are introduced and some of the published PLC routing papers are discussed, our network layer protocol concept is described with emphasis on the routing algorithm and route optimizations. The protocol is designed to optimize the energy efficiency of the PLC network. The next part of the paper briefly describes the network simulator and its model, which was used during the protocol development and debugging. Several networks with constant and dynamic channel parameters were simulated. The results are presented at the end of the paper. Final results proving energy efficiency and its positive influence on the network performance are presented in comparison to the minimum hop count metric.

RE-ATTEMPT: A New Energy-Efficient Routing Protocol for Wireless Body Area Sensor Networks

Modern health care system is one of the most popular Wireless Body Area Sensor Network (WBASN) applications and a hot area of research subject to present work. In this paper, we present Reliability Enhanced-Adaptive Threshold based Thermal-unaware Energy-efficient Multi-hop ProTocol (RE-ATTEMPT) for WBASNs. The proposed routing protocol uses fixed deployment of wireless sensors (nodes) such that these are placed according to energy levels. Moreover, we use direct communication for the delivery of emergency data and multihop communication for the delivery of normal data. RE-ATTEMPT selects route with minimum hop count to deliver data which downplays the delay factor. Furthermore, we conduct a comprehensive analysis supported by MATLAB simulations to provide an estimation of path loss, and problem formulation with its solution via linear programming model for network lifetime maximization is also provided. In simulations, we analyze our protocol in terms of network lifetime, packet drops, and throughput. Results show better performance for the proposed protocol as compared to the existing one.

Energy Efficient CCC based AODV Routing Protocol for Cognitive Radio Ad-Hoc Networks

Spectrum mobility in Cognitive radio ad-hoc networks introduces additional energy consumption apart from joint channel-path selection. Application data transmission in CR routing is based on channel-route path selected from common control channel (CCC). Hence, CCC plays a pivotal role in selecting and managing energy efficient channel-routes in Cognitive radio ad-hoc networks. State-of-the-art CR routing protocols either use 2.4 GHz unlicensed dedicated CCC (global) or licensed PU free CCC (local) for channel-path selection which results in higher energy consumption due to longer channel hop-count and higher control channel switching delays. Several small slices of unlicensed frequencies (433 MHz/868 MHz/902-928 MHz) are existing in lower spectral bands which are not efficiently utilized. This paper proposes a low rate (902 MHz) energy efficient CCC based AODV protocol to broadcast route control messages which select energy efficient channel- route paths through minimizing hop count, link failures, routing overhead and end-to-end data transmission delay. Experimental results show that the performance of the proposed AODV protocol outperforms compared with existing CCC based CR- AODV routing protocols. 

Understanding Error Propagation in Multihop Sensor Network Localization

In multihop localization procedures where not every node at unknown positions (i.e., sensors) can directly measure distances to nodes at known positions (i.e., anchors), sensor localization errors normally propagate (i.e., increase) as sensors progressively more distant from anchors are localized. To understand error propagation, we consider a primitive localization scenario: Nodes are deployed within a disk according to a homogeneous Poisson point process, the nodes around the disk center are anchors, the other nodes are sensors, and sensors are localized from the disk center to the outside in a hop-by-hop manner. Supposing noisy distance measurements between adjacent nodes, we analyze the quantitative relationship among sensor localization errors, minimal hop counts from sensors to anchors, the sensor density, and the noise level of distance measurements. This relationship clearly reflects the properties of error propagation and is greatly helpful to the design and deployment of large-scale sensor networks. Finally, a simulation analysis based on actual localization procedures and the Cramer-Rao lower bound confirms our results.

A Low-Cost Anchor Placement Strategy for Range-Free Localization Problems in Wireless Sensor Networks

The deployment of anchor nodes (or beacon nodes) is a key element in the design of range-free localization schemes for wireless sensor networks (WSNs). The majority of range-free localization schemes deploy numerous anchor nodes within the monitored region. However, in certain cases (e.g., hazardous areas), it may not be possible to manually install anchor nodes within the monitored region of a WSN. In this study, very few anchor nodes are installed at the boundary of a WSN monitored region to estimate the locations of unknown sensors. The locations of the unknown sensors are estimated based on the minimum hop counts to the anchor nodes. The average hop distance is estimated by applying parameters derived from prior experiments. The simulation results show that the range error of the proposed localization scheme can be as low as 0.15. The localization accuracy, computation cost, and communication cost of the proposed scheme are compared with those of the well-known DV-Hop method.

Randomized Throughput-Optimal Oblivious Routing for Torus Networks

In this paper, we study the problem of optimal oblivious routing for 1D and 2D torus networks. We introduce a new closed-form oblivious routing algorithm called W2TURN that is worst-case throughput optimal for 2D torus networks. W2TURN is based on a weighted random selection of paths that contain at most two turns. Restricting the maximum number of turns in routing paths to just two enables a simple deadlock-free implementation of W2TURN. In terms of average hop count, W2TURN outperforms the best previously known closed-form worst-case throughput optimal routing algorithm called IVAL [CHECK END OF SENTENCE]. When the network radix is odd, W2TURN achieves the minimum average hop count that can be achieved with 2-turn paths while remaining worst-case throughput optimal. When the network radix is even, W2TURN comes very close to achieving the minimum average hop count while remaining worst-case throughput optimal, within just 0.72 percent on a 12\times 12 torus. We also describe another routing algorithm based on weighted random selection of paths with at most two turns called I2TURN and show that I2TURN is equivalent to IVAL. However, I2TURN eliminates the need for loop removal at runtime and provides a closed-form analytical expression for evaluating the average hop count. The latter enables us to demonstrate analytically that W2TURN strictly outperforms IVAL (and I2TURN) in average hop count. Finally, we present a new optimal weighted random routing algorithm for rings called Weighted Random Direction (WRD). WRD provides a closed-form expression for the optimal distribution of traffic along the minimal and nonminimal directions in a ring topology to achieve minimum average hop count while guaranteeing optimal worst-case throughput. Based on our evaluations, in addition to being worst-case throughput optimal, W2TURN and WRD also perform well in the average case, and outperform the best previously known worst-case throughput optimal routing algorithms with closed-form descriptions in latency and throughput over a wide range of traffic patterns.

Gray Relevance Algorithm Based Routing Protocol in Ad Hoc Network

The characteristics of nodes moving arbitrarily and the network topology changing frequently lead to AODV routing protocol, which uses minimum hop-count as the metric for route selection, facing intermittent connectivity frequently which would cause QoS of network degradation in Ad Hoc Network. In this paper, we integrate three cross layer infor-mation which consists of the remaining energy of nodes, the remaining queue length and the hop-count from source node to destination node. Then we present the GRA-AODV routing protocol based on the gray relevance algorithm. By comparing the simulation and experimental results, in the case of slightly increase in routing overhead, the improved Gray Relevance Algorithm-AODV routing possesses lower average end to end delay and lower packet loss rate, and it has superior robustness in the mobile Ad Hoc Network with network topology changing frequently.

Range-Free Localization Scheme in Wireless Sensor Networks Based on Bilateration

A low-cost yet effective localization scheme for wireless sensor networks (WSNs) is presented in this study. The proposed scheme uses only two anchor nodes and uses bilateration to estimate the coordinates of unknown nodes. Many localization algorithms for WSNs require the installation of extra components, such as a GPS, ultrasonic transceiver, and unidirectional antenna, to sensors. The proposed localization scheme is range-free (i.e., not demanding any extra devices for the sensors). In this scheme, two anchor nodes are installed at the bottom-left corner (Sink X) and the bottom-right corner (Sink Y) of a square monitored region of the WSN. Sensors are identified with the same minimum hop counts pair to Sink X and Sink Y to form a zone, and the estimated location of each unknown sensor is adjusted according to its relative position in the zone. This study compares the proposed scheme with the well-known DV-Hop method. Simulation results show that the proposed scheme outperforms the DV-Hop method in localization accuracy, communication cost, and computational complexity.

An Oblivious Routing Algorithm for 3D Mesh Networks to Achieve a New Worst-Case Throughput Bound

1/2 network capacity is often believed to be the limit of worst-case throughput for three-dimension (3D) mesh networks. However, this paper provides a new worst-case throughput bound, which is higher than 1/2 network capacity, for odd radix 3D mesh networks. In addition, we propose a routing algorithm called uniform solo-minimal (USM) routing that can achieve this new worst-case throughput bound in odd radix mesh networks. For the even radix case, we prove that USM achieves the optimal worst-case throughput, namely, half of network capacity. USM considers all routing paths with at most one dimensional minimal-distance routing and distributes the traffic loads uniformly to other two left dimensions. Theoretical analysis and simulation results show that USM outperforms existing routing algorithms in worst-case throughput. Moreover, USM achieves good average-throughput and performs very well under different traffic matrices at the expense of (5/3)× minimal average hop count.

Energy-aware routing in hybrid optical network-on-chip for future multi-processor system-on-chip

With the development of Multi-Processor System-on-Chip (MPSoC) in recent years, the intra-chip communication is becoming the bottleneck of the whole system. Current electronic network-on-chip (NoC) designs face serious challenges, such as bandwidth, latency and power consumption. Optical interconnection networks are a promising technology to overcome these problems. In this paper, we study the routing problem in optical NoCs with arbitrary network topologies. Traditionally, a minimum hop count routing policy is employed for electronic NoCs, as it minimizes both power consumption and latency. However, due to the special architecture of current optical NoC routers, such a minimum-hop path may not be energy-wise optimal. Using a detailed model of optical routers we reduce the energy-aware routing problem into a shortest-path problem, which can then be solved using one of the many well known techniques. By applying our approach to different popular topologies, we show that the energy consumed in data communication in an optical NoC can be significantly reduced. We also propose the use of optical burst switching (OBS) in optical NoCs to reduce control overhead, as well as an adaptive routing mechanism to reduce energy consumption without introducing extra latency. Our simulation results demonstrate the effectiveness of the proposed algorithms.

A Novel Range-Free Localization Scheme for Wireless Sensor Networks

This paper present a low-cost yet effective localization scheme for the wireless sensor networks. There are many studies in the literature of locating the sensors in the wireless sensor networks. Most of them require either installing extra hardware or having a certain amount of sensor nodes with known positions. The localization scheme we propose in this paper is range-free, i.e., not requiring extra hardware devices, and meanwhile it only needs two anchor nodes with known position. Firstly, we install the first anchor node at the lower left corner (Sink X) and the other anchor node at the lower right corner (Sink Y). Then we calculate the minimum hop counts for each unknown node to both Sink X and Sink Y. According to the minimum hop count pair to Sink X and Sink Y of each node, we can virtually divide the monitored region into zones. We then estimate the coordinate of each sensor depending on its located zone. Finally, we adjust the location estimation of each sensor according to its relative position in the zone. We simulate our proposed scheme and the well-known DV-Hop method. The simulation results show that our proposed scheme is superior to the DV-Hop method under both low density and high density sensor deployments.

Enhancing Performance of MAODV Routing Protocol for Wireless Mesh Network using Integrated Multiple Metrics Technique (IMMT)

Customarily, the design of an efficient routing protocol for Wireless Mesh Networks (WMNs) demands suffi- cient consideration of the pertinent features. This is due to the fact that WMNs can be permanent or semi-permanent networks. Moreover, a reliable path from the source to the destination can be maintained using an improved and better performance metrics. Currently, the most widely used performance metric is the minimum hop-count which is based on the assumption that communication links are either working well or not working at all. This assumption is true for wired networks however this is impractical for wireless networks where numerous links suffer from intermediate loss ratios, low throughput, inter- ference and other inherent limitations. Consequently, researchers have proposed a number of performance metrics for WMNs. It has also been shown that integrating multiple performance metrics into a routing protocol is effective for attaining optimal performance since it is highly probable that a single performance metric will not be able to satisfy the comprehensive re- quirements of WMNs. This paper presents a technique of integrating multiple routing metrics in order to optimize the per- formance of a routing protocol. The proposed technique is implemented on Multicast Ad-hoc On-Demand Distance Vector (MAODV) routing protocol. Simulation results show a statistically significant performance improvement over standard MAODV for WMNs.

A Self-Optimizing Scheme for Energy Balanced Routing in Wireless Sensor Networks Using SensorAnt

Planning of energy-efficient protocols is critical for Wireless Sensor Networks (WSNs) because of the constraints on the sensor nodes' energy. The routing protocol should be able to provide uniform power dissipation during transmission to the sink node. In this paper, we present a self-optimization scheme for WSNs which is able to utilize and optimize the sensor nodes' resources, especially the batteries, to achieve balanced energy consumption across all sensor nodes. This method is based on the Ant Colony Optimization (ACO) metaheuristic which is adopted to enhance the paths with the best quality function. The assessment of this function depends on multi-criteria metrics such as the minimum residual battery power, hop count and average energy of both route and network. This method also distributes the traffic load of sensor nodes throughout the WSN leading to reduced energy usage, extended network life time and reduced packet loss. Simulation results show that our scheme performs much better than the Energy Efficient Ant-Based Routing (EEABR) in terms of energy consumption, balancing and efficiency.

An energy-balancing clustering approach for gradient-based routing in wireless sensor networks

Clustering significantly reduces the energy consumption of each individual sensor in a wireless sensor network (WSN), and also increases the communication load on cluster heads. Because of the unbalanced energy consumption among cluster heads, the hot spots problem will arise when using the multihop forwarding model for the intercluster communication. Unequal clustering is an effective way to balance the energy consumption of cluster heads. In this paper, we present an Energy-Balancing unequal Clustering Approach for Gradient-based routing (EBCAG) in wireless sensor networks. It partitions the nodes into clusters of unequal size, and each sensor node maintains a gradient value, which is defined as its minimum hop count to the sink. The size of a cluster is decided by the gradient value of its cluster head, and the data gathered from the cluster members should follow the direction of descending gradient to reach the sink. Simulation results show that EBCAG balances the energy consumption among the cluster heads, and significantly improves the network lifetime.

BANDWIDTH-SENSITIVE ROUTING: FROM INDIVIDUALISM TO COLLECTIVISM

The routing metric is the measure by which a routing protocol chooses paths between pairs of source and destination nodes in the network. Routing metric has a significant impact on the network resource utilization. The most well-known intradomain routing disciplines in today's Internet are the minimum hop count routing (e.g., Routing Information Protocol (RIP)) and the shortest path routing (e.g., Open Shortest Path First (OSPF) and intermediate system to system (IS-IS)). In the former case, the routing metric is the number of hops over the path and in the latter one, the metric is evaluated with respect to an additive link weight function. In this article, we study the impact of these two types of metrics on routing of bandwidth-sensitive traffic in the network. We first argue that the main characteristics of a bandwidth-sensitive routing problem can be captured elegantly through transforming the problem from the networking domain into the sociology area. This model reveals that the minimum hop count is indeed a dominant Individualist view of resource management in the Internet, whereas the shortest-path metric has a collectivist trend. We then propose a novel hybrid metric, which combines the benefit of both sociological systems. Through extensive simulations, we show that our proposed scheme yields much better results, with respect to the number of admitted requests and delay of paths, compared with other well-known counterparts.