Greedy Forwarding Strategy Research Articles

An adaptive and multi-path greedy perimeter stateless routing protocol in flying ad hoc networks

In recent years, flying ad hoc networks (FANET), formed from unmanned aerial vehicles (UAVs), have absorbed the attention of academic and industrial research communities due to their many applications in military and civilian fields. FANETs benefit from unique features, including highly moving UAVs and dynamic topological structure. Therefore, most existing routing protocols, such as the greedy perimeter stateless routing (GPSR), are not compatible with the FANET environment and its specific features. To improve the performance of GPSR in FANET, it is important to address several challenges, namely the selection of the right period for broadcasting hello messages in the network, the selection of the right criteria for selecting the next-hop node, and the improvement of reliability in the data transfer process. In this paper, an adaptive and multi-path greedy perimeter stateless routing (AM-GPSR) protocol is suggested in FANETs. It includes two new strategies, namely adaptive hello strategy and multi-path greedy forwarding strategy. The adaptive hello strategy defines a special hello broadcast period for each UAV according to its speed and error between two estimated and actual positions. Furthermore, the greedy forwarding strategy carries out a filtering operation on candidate nodes and eliminates border UAVs and those that are far from the destination. Then, candidate UAVs are prioritized based on the time to reach the destination and buffer capacity, and UAVs with higher priorities are chosen to send data packets. Finally, AM-GPSR applies a greedy multi-path forwarding strategy to increase reliability in the data transmission process. Lastly, the simulation of AM-GPSR is done via the network simulator version 2 (NS2) to evaluate its performance. This evaluation process includes two different scenarios, i.e. change in the speed of UAVs and change in their communication range. In this process, AM-GPSR is compared with three other methods, namely the aerial greedy geographic routing (AGGR) protocol, the geolocation assisted aeronautical routing protocol (AeroRP), and GPSR. This comparison shows the successful performance of AM-GPSR in terms of delivery success rate, throughput, and delay. Although the control overhead of the proposed method is more than that of AGGR.

Weight-Based PA-GPSR Protocol Improvement Method in VANET.

Vehicle Ad-hoc network (VANET) can provide technical support and solutions for the construction of intelligent and efficient transportation systems, and the routing protocol directly affects the efficiency of VANET. The rapid movement of nodes and uneven density distribution affect the routing stability and data transmission efficiency in VANET. To improve the local optimality and routing loops of the path-aware greedy perimeter stateless routing protocol (PA-GPSR) in urban sparse networks, a weight-based path-aware greedy perimeter stateless routing protocol (W-PAGPSR) is proposed. The protocol is divided into two stages. Firstly, in the routing establishment stage, the node distance, reliable node density, cumulative communication duration, and node movement direction are integrated to indicate the communication reliability of the node, and the next hop node is selected using the weight greedy forwarding strategy to achieve reliable transmission of data packets. Secondly, in the routing maintenance stage, based on the data packet delivery angle and reliable node density, the next hop node is selected for forwarding using the weight perimeter forwarding strategy to achieve routing repair. The simulation results show that compared to the greedy peripheral stateless routing protocol (GPSR), for the maximum distance-minimum angle greedy peripheral stateless routing (MM-GPSR) and PA-GPSR protocols, the packet loss rate of the protocol is reduced by an average of 24.47%, 25.02%, and 14.12%, respectively; the average end-to-end delay is reduced by an average of 48.34%, 79.96%, and 21.45%, respectively; and the network throughput is increased by an average of 47.68%, 58.39%, and 20.33%, respectively. This protocol improves network throughput while reducing the average end-to-end delay and packet loss rate.

UF‐GPSR: Modified geographical routing protocol for flying ad‐hoc networks

AbstractFlying Ad‐hoc Networks (FANETs) has recently gained significant exposure for their emerging military, civil, and commercial applications. In FANETs, all Unmanned Aerial Vehicles (UAVs) can communicate within a restricted wireless communication range without fixed infrastructure. However, the highly dynamic nature of UAVs imposes a significant issue in FANET's communications. Therefore, designing an effective routing strategy is always necessary for sustaining appropriate network performance in FANETs. This paper is interested in modifying Greedy Perimeter Stateless Routing (GPSR) protocol named Utility Function based Greedy Perimeter Stateless Routing (UF‐GPSR) protocol for FANETs. The proposed approach optimizes the greedy forwarding strategy by considering multiple vital parameters of UAVs: residual energy ratio, distance degree, movement direction, link risk degree, and speed, respectively. The proposed UF‐GPSR applies the utility function on these parameters to enhance the routing performance by selecting optimal next‐hop within the communication range. The effectiveness of the proposed work is mathematically evaluated and then simulated through the NS‐3.23 simulator. The experimental outcomes verify that the proposed routing approach enhances the packet delivery ratio and throughput while decreasing packet drop ratio and delay compared to the other routing approaches: GPSR and GPSR‐PPU.

Emergency Data Transmission Mechanism in VANETs using Improved Restricted Greedy Forwarding (IRGF) Scheme

One of the most critical tasks in Vehicular Ad-hoc Networks (VANETs) is broadcasting Emergency Messages (EMs) at considerable data delivery rates (DDRs). The enhanced spider-web-like Transmission Mechanism for Emergency Data (TMED) is based on request spiders and authenticated spiders to create the shortest route path between the source vehicle and target vehicles. However, the adjacent allocation is based on the DDR only and it is not clear whether each adjacent vehicle is honest or not. Hence, in this article, the Improved Restricted Greedy Forwarding (IRGF) scheme is proposed for adjacent allocation with the help of trust computation in TMED. The trust and reputation score value of each adjacent vehicle is estimated based on successfully broadcast emergency data. The vehicles’ position, velocity, direction, density, and the reputation score, are fed to a fuzzy logic (FL) scheme, which selects the most trusted adjacent node as the forwarding node for broadcasting the EM to the destination vehicles. Finally, the simulation results illustrate the TMED-IRGF model’s efficiency compared to state-of-the-art models in terms of different network metrics.

Dynamic Virtual Topology Aided Networking and Routing for Aeronautical Ad-Hoc Networks

Aeronautical Ad-hoc Networks (AANETs) have been proposed as the promising complement to terrestrial networks for promoting the global interconnection to provide in-flight network service, emergency communication, vessel traffic service, etc. However, the large network scale of AANETs may induce severe synchronization overhead when the traditional topology-based networking algorithms are adopted. Moreover, the high-dynamic topology and changeable flight routes make the existing position-based routing algorithms suffer loop routing and forwarding failure. Motivated by these problems, this paper aims at developing efficient and low-cost networking and routing algorithms relying on the concept of dynamic virtual topology which organizes the disordered topology of AANETs into a structural and simplified one. The basic idea is that each connected aircraft is assigned with a unique and sequentially increased Virtual Identifier (VID) and thus all the connected aircrafts are organized into a virtual cluster consisting of one trunk and several branches. An event-driven synchronization mechanism is leveraged for maintaining the virtual topology as well as relieving the communication burden imposed by periodical broadcasting. By jointly considering the geographic locations and the virtual locations of aircrafts, we formulate the routing problem in AANETs as a weighted distance minimization problem, and further propose a novel routing algorithm, namely Trunk-Branch Cooperation aided Routing (TBCR) algorithm. Specifically, TBCR employs the geographic greedy forwarding strategy for enhancing its flexibility and boosts the routing efficiency by adopting the loop-free virtual topology based local forwarding. For extending the networking and routing algorithms to the global range, a multi-domain routing solution is also provided. Extensive experimental results show that the proposed Virtual Topology based Networking (VTN) cooperated with TBCR can reduce at least 30% average end-to-end transmission delay in large-scale AANETs and provide more than 90% lower synchronization overhead than the existing solutions.

LDAB-GPSR: Location PreDiction with Adaptive Beaconing – Greedy Perimeter Stateless Routing Protocol for Mobile Ad Hoc Networks

In mobile ad-hoc networks (MANET), nodes are randomly distributed and move freely, and hence the network may face rapid and unexpected topological changes. In this paper, an improved greedy perimeter stateless routing protocol, called “LDAB-GPSR”, is proposed. LDAB-GPSR mainly focuses on maximizing the packet delivery ratio while minimizing the control overhead. In order to accomplish this, two techniques are introduced, the first one is the location prediction technique in which the greedy forwarding strategy is improved by choosing more stable routes for data forwarding. The second one is the adaptive beaconing technique in which the slow start algorithm is employed to adapt the beacon packet interval time based on the mobility of nodes and the data traffic load instead of using the periodic beaconing strategy. These two strategies together improve the overall performance of the GPSR routing protocol. The performance of the new proposed protocol is evaluated by carrying out several NS-2.35 simulation experiments. The simulation results show that LDAB-GPSR protocol outperforms the GPSR+Predict protocol in terms of packet delivery ratio, control traffic overhead, end to end delay, and throughput. The ratios of enhancement approaches 40%.

Greedy Forwarding Routing Schemes using an Improved K-Means Approach for Wireless Sensor Networks

Reducing energy consumption in wireless sensor networks (WSNs) is one of the main ways to extend network lifetime since, in most cases, sensor nodes are battery-powered and are not rechargeable. One way to achieve this goal is to reduce the amount of redundant data sent to the base station (BS) through an aggregation operation carried out by the coordinating nodes. The clustering approach is considered as one of the most energy-efficient approaches for routing data in WSNs because in this approach the cluster-heads are responsible for the aggregation of the data packets, which reduces the amount of data sent to the BS. In this paper, we propose an approach based on an improved version of the K-Means method. This approach allows to find the appropriate number of clusters and generate clusters based on the radio communication of the nodes (RC). Moreover, to send data to the BS, we propose three greedy forwarding schemes. The first is a pure greedy forwarding (DKM-GF), the second is based on the distance and the residual energy of the relay nodes (DKM-GFE) and the third on the distance, the residual energy of the relay nodes and the energy dissipated to send data from a node to the forwarding node (DKM-GF2E). The proposed routing schemes have been implemented over MATLAB simulator. The results obtained show that our proposals bring significant improvements in terms of energy consumption, network lifetime and the number of packets sent to the base station compared to other protocols.

A Novel Greedy Forwarding Mechanism Based on Density, Speed and Direction Parameters for Vanets

In the recent years, the study and developments of networks that do not depend on any pre-existing infrastructure have been very popular. Vehicular Ad Hoc Networks (VANETs) belong to the class of these networks, in which each vehicle participates in routing by transmitting data for other nodes (vehicles). Due to the characteristics of VANET (e.g. high dynamic topology, different communication environment, frequently link breakage…), the routing process still one of the most challenging aspects. Hence, many routing protocols have been suggested to overcome these challenges. Moreover, routing protocols based on the position of vehicles are the most popular and preferred class, thanks to its many advantages like the less control overhead and the scalability. However, this class suffer from some problems such as frequent link breakages caused by the high-mobility of vehicles, which cause a low PDR and throughput. In this investigation, we introduce a novel greedy forwarding strategy used to create a new routing protocol based on the position of vehicles, to reduce the link breakages and get a stable route that improves the PDR and throughput. The proposed Density and Velocity (Speed, Direction) Aware Greedy Perimeter Stateless Routing protocol (DVA-GPSR) is based on the suggested greedy forwarding technique that utilizes the density, the speed and the direction for selecting the most convenient relaying node candidate. The results of simulation prove that DVA-GPSR protocol outperforms the classical GPSR in all studied metrics like PDR, throughput, and the ratio of routing overhead by changing the quantity of vehicles in urban and highway scenarios.

Routing Strategy of Integrated Satellite-Terrestrial Network Based on Hyperbolic Geometry

The integrated satellite-terrestrial network has the characteristics of large scale, complex, high dynamic and heterogeneousness. Adopting traditional routing methods in the integrated satellite-terrestrial network will cause problems of poor scalability and large routing overhead. Greedy forwarding strategy based on network mapping with hyperbolic geometry works well in large scale network. However, there is no study on applying the network mapping with hyperbolic geometry to complex networks beyond two dimensions, including the integrated satellite-terrestrial network. Based on the method of spherical polar projection, this paper proposes a hyperbolic coordinates mapping algorithm in three-dimensional geographic space suitable for the integrated satellite-terrestrial network. This algorithm gives nodes of heterogeneous layers in the integrated satellite-terrestrial network a unified expression based on four-dimensional hyperbolic coordinates, which helps to quickly identify and locate nodes without global information distribution and scheduling when routing. The routing strategy using greedy forwarding strategy based on this algorithm only costs low storage overhead, as it does not need routing tables. Simulations demonstrate that the performance of the algorithm is hardly affected by the exponential expansion of the network size, which means the property of scalability is excellent. Also, it is stable under heterogeneous network structure, and maintains a stable routing success rate for optimal path selection around 93% with a time complexity of O(n).

An reactive void handling algorithm in sensor networks and IoT emergency management

Geographic routing in sensor networks and internet of things (IoT) prevails recent years as the localization technology advancing. The greedy forwarding is one of outstanding geographic routing schemes for its simplicity and efficiency. The greedy forwarding work efficiently in dense network, but may fails to send a packet further towards destination when encountering communication voids. Thus most geographic routing consists of two elements: 1) greedy forwarding scheme is used as long as possible, 2) a backup scheme resumes tasks when greedy forwarding fails due to local minimum. In this paper, we propose a novel void handling approach that detecting the boundary of voids and then a node in convex hull of boundary is selected as relay node. With the knowledge of relay node, the packets from source run around the void to construct path with less hop count. Simulation results indicate that this algorithm outperform classical geographic routing GPSR in several metrics.

Performance Evaluation of Depth Adjustment and Void Aware Pressure Routing (DA-VAPR) Protocol for Underwater Wireless Sensor Networks

Abstract Underwater wireless sensor network (UWSN) has gained its popularity as a powerful technology for monitoring oceans, sea and river. The sensor node drifting along with ocean current offers 4D (space and time) monitoring for real-time underwater application. However, the main challenge arises from the underwater acoustic communication that results in high propagation delay, packet loss and overhead in the network. In order to overcome these issues, a depth adjustment and void aware pressure routing protocol is proposed for UWSN. A greedy forwarding strategy is used to forward the packet. In case a node fails to forward the packet using greedy forwarding strategy, then it immediately switches to the recovery mode. In the recovery mode, the node determines the new depth using particle swarm optimization technique. The global best value gives the new depth with minimum displacement. The void node forwards the packet with minimum displacement without any packet loss and delay.

Secure Data Sharing Framework via Hierarchical Greedy Embedding in Darknets

Geometric routing, which combines greedy embedding and greedy forwarding, is a promising approach for efficient data sharing in darknets. However, the security of data sharing using geometric routing in darknets is still an issue that has not been fully studied. In this paper, we propose a Secure Data Sharing framework (SeDS) for future darknets via hierarchical greedy embedding. SeDS adopts a hierarchical topology and uses a set of secure nodes to protect the whole topology. To support geometric routing in the hierarchical topology, a two-level bit-string prefix embedding approach (Prefix-T) is first proposed, and then a greedy forwarding strategy and a data mapping approach are combined with Prefix-T for data sharing. SeDS guarantees that the publication or request of a data item can always pass through the corresponding secure node, such that security strategies can be performed. The experimental results show that SeDS provides scalable and efficient end-to-end communication and data sharing.

Hybrid opportunistic and position-based routing protocol in vehicular ad hoc networks

Vehicular ad hoc networks (VANETs) are kind of mobile ad hoc networks (MANETs) which are used to provide communications between mobile vehicles in urban and highway scenario. Due to special characteristics of VANETs such as dynamic topology, frequent disconnection, high vehicular speed and propagation model, designing an efficient routing scheme is one of the most important key issues. In this paper, we propose a hybrid opportunistic and position-based routing protocol in VANETs by considering parameters such as position of nodes, link quality and node density. The proposed method uses a greedy forwarding scheme, in which a sender vehicle chooses a neighbor node with the highest geographical progress to increase the least number of hops between source node and destination vehicle node. Based on opportunistic and position based strategy, the proposed scheme selects optimal candidate nodes and determines appropriate priority for transmitting data. Also, the proposed scheme determines and removes the expired nodes from the routing process. The simulation results in ns-2 indicate performance improvement in terms of packet delivery rate (PDR), throughput and end-to-end delay.

Hot Spot Phenomenon and Greedy Routing Failure in Mobile Ad-hoc Networks

Lately, Greedy Forwarding Strategy (GFS) is express as a basic mechanistic in geographic routing for Mobile Ad Hoc Networks (MANETs). GFS employs the shortest path between two connected nodes. The research’s analysis of networks that using GFS indicates that some areas of the MANET are more decumbent to high traffic load compared with other places. This situation is called hot spot phenomenon. Accordingly, these hot spot nodes become constrained in terms of many issues and seem to be died fast. The performance of GFS becomes limited to these hot spot nodes. The whole MANET fails, as GFS fails to function well in this area. This paper takes an in depth look at the reason behind greedy failure. Lastly, the work concludes the most appropriate characteristics that should be consider for enhancing greedy scheme to be compatible with the unique features of MANET.

TMED: A Spider-Web-Like Transmission Mechanism for Emergency Data in Vehicular Ad Hoc Networks

The vehicular ad hoc network (VANET) is an emerging mobile ad hoc network, which is an important component of the Internet of Things and has been widely applied in intelligent transportation systems in recent years. For large-scale VANETs, it is important to design efficient transmission schemes for time critical emergency data. Greedy perimeter stateless routing protocol is a typical geographic-based routing protocol and greedy perimeter coordinator routing protocol is typical for map-based but they do not consider the QoS of the transmission link and hence are not suitable for emergency data transmissions. Some bioinspired protocols and situation-aware protocols are more suitable for emergency situations. However, they have some limitations in terms of the computational complexity and convergence rate which can cause large time delays. In this paper, we propose a novel spider-web-like transmission mechanism for emergency data (TMED) in vehicular ad hoc networks, in which a spider-web-like transmission model combining geographic information system and electronic maps is established. In this mechanism, the request-spiders and confirmed-spiders are sent out to obtain the transmission path from a source vehicle to a destination vehicle to improve the packet delivery ratio and average transmission delay of emergency data. TMED combines a dynamic multipriority message queue management method with a restricted greedy forwarding strategy based on position prediction to significantly reduce the end-to-end delay of packets. We use SUMO and NS2 to simulate TMED in a city scenario and compare its performance with GPSR, GPCR, and ACAR based on the packet delivery ratio, average transmission delay, and routing overhead. The simulation results show that TMED outperforms these previously proposed protocols.

An Enhanced Queue Management Approach for Greedy Routing in MANETs

Mobile Ad-hoc network (MANET) is the guiding technology of ubiquitous era and a cornerstone in the 4G communication architecture. MANET has limited resources and characterized with high mobility and frequent topology change. Routing in MANET should follow these constrains, otherwise, it can severely degrade the performance of MANET. Owing to Greedy routing (GFS) nature in MANET, a certain part of the MANET becomes congested before other parts. In such area the nodes have failed to forward packets in a timely manner or drop them, thus such nodes called Network Holes. This paper presents a simple and efficient enhanced GFS routing algorithm called Intelligent Fuzzy logic Greedy forwarding Scheme (IFGFS). IFGFS consider the De-congestion level of each mobile node as another selective metric besides distance. In order to validate our algorithm, we rely on a wide simulation experiments. The evaluation results showed the correctness of our new proposed algorithm the adaptive- congestion IFGFS which maximize the performance of the network.

ENHANCED ROUTE SELECTION APPROACH OF GPSR USING MULTIPATH FORWARDING IN VANET

The Vehicular Ad-Hoc Network is infrastructure less network in which vehicles are connected without wires. Routing in Vehicular Ad-hoc Network is challenging nowadays due to increased no of a vehicle, the high mobility of nodes, dynamically changing topology and highly partitioned network, so the challenges on the roads are also increased like roads are full, the safety problem, speed etc. GPSR is a position based algorithm. GPSR uses source node and destination node’s position to forward packets. This protocol uses Greedy Forwarding and Perimeter Forwarding strategies for packet forwarding from source to destination. The proposed system uses the modify beacon packet strategy which includes source node and destination node parameters to route packet. All nodes are initially selected as forwarding node which is a letter on reduced to final routing path after acknowledgment. The proposed system improves the parameters like Packet Delivery Ratio and maintains a number of hop counts.

Fog computing enabling geographic routing for urban area vehicular network

Geographic routing scheme has received considerable attention recently. We present a position-based routing scheme called improved geographic routing (IGR) for the inter-vehicle communication in city environments. IGR uses the vehicular fog computing to make the best utilization of the vehicular communication and computational resources. IGR consists of two modes: (i) junction selection according to the distance to the destination and the vehicle density of each street, and (ii) an improved greedy forwarding strategy to transmit a data packet between two junctions. In the improved greedy forwarding mode, link error rate is considered in the path selection. Simulations are conducted to evaluate the performance of IGR. Simulation results show that IGR has a significant improvement in terms of the achieved packet rate and end-to-end delay.

An Improved Greedy Forwarding Scheme in MANETs

Position-based routing protocols are widely accepted efficient solution for routing in MANETs. The main feature of position-based routing protocols is to use greedy forwarding methods to route data. The greedy forwarding methods select a node, either having maximum progress towards destination (distance-based principle) or minimum deviation with line between source and destination (direction-based strategy). The first method minimizes the hopcount in a path and on the other hand, second method minimizes the spatial distance between source and destination. The distance-based routing has a great impact on the selection of reliable node and the direction based routing plays a major role to increase the stability of route towards destination. Therefore, in this paper authors propose a weighted forwarding method, which combines both the selection, schemes to select an optimal next forwarding node in a range. The simulation results show that the proposed scheme performs better than existing position-based routing protocols.

Link residual lifetime-based next hop selection scheme for vehicular ad hoc networks

In Vehicular Ad Hoc Networks (VANETs), geographic routing protocols rely on a greedy strategy for hop by hop packet forwarding by selecting vehicle closest to the destination as the next hop forwarding node. However, in a high-mobility network such as VANET, the greedy forwarding strategy may lead to packet transmission failure since it does not consider the reliability of the newly formed link when next hop forwarding nodes are chosen. In this paper, we propose a scheme for next hop selection in VANETs that takes into account the residual lifetime of the communication links. In the proposed approach, a source vehicle selects a forwarding vehicle from a given set of candidate vehicles by estimating the residual lifetime of the corresponding links and finding the link with maximum residual lifetime. Initially, we present Kalman filter based approach for estimating the link residual lifetime in VANETs. We then present the details of the proposed next hop selection method. Simulation results show that the proposed scheme exhibits better performance in terms of packet delivery ratio and average end-to-end delay as compared to other conventional method.