OLSR Research Papers - Academia.edu (original) (raw)

With the rapid development in mobile Wireless Sensor Networks (WSNs), it has become very essential to focus on the efficiency in performance of small sensing nodes operating in WSNs. While designing a routing protocol for mobile sensor... more

With the rapid development in mobile Wireless Sensor Networks (WSNs), it has become very essential to focus on the efficiency in performance of small sensing nodes operating in WSNs. While designing a routing protocol for mobile sensor nodes, the quality parameters like end-to-end delays and routing overhead are always considered. Moreover, the nodes in wirelessly connected mobile networks consume considerable power on routing more than other functionalities. Any modification in a standard routing protocol can also affect routing overhead, end-to-end delays, and energy consumption of nodes. In this paper a new hybrid routing protocol, named as State-Aware Link Maintenance Approach (SALMA), is introduced which is based on Dynamic Source Routing (DSR) and Optimized Link State Routing (OLSR) protocols. The work also focuses on the activeness of nodes in the network operations and defines three states of nodes, that is, white, gray, and black. The work concludes that the proposed protocol gives improvements in some quality of service metrics like lower delay than DSR, lower routing overhead than OLSR, and lesser energy consumption by the network nodes.

Development of multimedia from year to year increasing with the growing support of computer networks such as wireless LAN (WLAN) as a media intermediary. The one of method is streaming multimedia delivery over the internet from the server... more

Development of multimedia from year to year increasing with the growing support of computer networks such as wireless LAN (WLAN) as a media intermediary. The one of method is streaming multimedia delivery over the internet from the server to the client to respond to client requests to a video and audio contained in a computer network. Factors that affect the streaming is bandwidth. These factors may cause the process stream is often disrupted when there is not enough bandwidth so that resulted in the loss and delay in delivery. To reduce the occurrence of loss and delay, a routing protocol is needed that can support multimedia service quality package that will be passed on wireless LAN networks. In this paper will be evaluated on the WLAN performance multimedia services with the help of routing protocol Optimized Link State Routing (OLSR).

Wireless sensor networks are useful for streaming multimedia in infrastructure-free and hazardous environments. However, these networks are quite different from their wired counterpart and are composed of nodes with constrained bandwidth... more

Wireless sensor networks are useful for streaming multimedia in infrastructure-free and hazardous environments. However, these networks are quite different from their wired counterpart and are composed of nodes with constrained bandwidth and energy. Multiple-path transmission is one of the methods for ensuring QoS routing in both wired and wireless environment. Directed diffusion, a well known wireless sensor network protocol, only routes packets through a single path, which barely meets the throughput requirement of multimedia data. Instead, we propose a multipath algorithm based on directed diffusion that reinforces multiple routes with high link quality and low latency. This algorithm retains the merits of the original directed diffusion algorithms, including its energy efficiency and scalability. A hybrid metric of link quality and latency is used as the criterion for path selection. In order to select disjoint paths, we propose a scheme for reinforced nodes to respond negatively to multiple reinforcement messages. We use the NS-2 simulation tool with video trace generated by Multiple Description Coding (MDC) to evaluate the performance. The results show that our algorithm gives better throughput and delay performance, i.e higher video quality, than standard directed diffusion that transmits over a single path, with low overheads and energy consumption.

IETF MANET (mobile ad hoc network) working group has standardized AODV (ad hoc on-demand distance vector) and OLSR (optimized link state routing) as its reactive and proactive routing protocols, respectively. In addition, from the... more

IETF MANET (mobile ad hoc network) working group has standardized AODV (ad hoc on-demand distance vector) and OLSR (optimized link state routing) as its reactive and proactive routing protocols, respectively. In addition, from the transport layer's perspective, TCP (transmission control protocol) is still needed for MANET since it is widely used in the current Internet and suitable for smooth integration with the fixed Internet. Particularly, TCP has its variants, namely TCP-Reno and TCP-Vegas. However, there has been no research work on extensive performance comparison of TCP-Reno and TCP-Vegas over AODV and OLSR. This paper is the first trial to perform the research by using ns-2 simulator. Through the extensive simulations, we found that which to select among routing protocols is more important than which to select among TCP variants, because the performance difference between TCP-Reno and TCP-Vegas over any selected routing protocol is not so much outstanding.

Mobile Ad-Hoc network is a collection of mobile nodes in communication without using infrastructure. As the real-time applications used in today’s wireless network grow, we need some schemes to provide more suitable service for them. We... more

Mobile Ad-Hoc network is a collection of mobile nodes in communication without using infrastructure.
As the real-time applications used in today’s wireless network grow, we need some schemes to provide
more suitable service for them. We know that most of actual schemes do not perform well on traffic which
is not strictly CBR. Therefore, in this paper we have studied the impact, respectively, of mobility models
and the density of nodes on the performances (End-to-End Delay, Throughput and Packet Delivery ratio)
of routing protocol (Optimized Link State Routing) OLSR by using in the first a real-time VBR (MPEG-4)
and secondly the Constant Bit Rate (CBR) traffic. Finally we compare the performance on both cases.
Experimentally, we considered the three mobility models as follows Random Waypoint, Random
Direction and Mobgen Steady State. The experimental results illustrate that the behavior of OLSR change
according to the model and the used traffics.

Voice over Internet Protocol (VoIP) may provide good services through Vehicular ad hoc networks (VANETs) platform by providing services to many application scenarios range from safety to comfort. However, VANETs networks introduce many... more

Voice over Internet Protocol (VoIP) may provide good services through Vehicular ad hoc networks
(VANETs) platform by providing services to many application scenarios range from safety to comfort.
However, VANETs networks introduce many challenges for supporting voice with QoS requirements. In
this paper, our study is based on Inter-Vehicle voice streaming rely on multi-hop fashion. For this task, a
performance evaluation of various audio CODECs will be analyzed by mean of simulations.
Furthermore, we test the impact of network environment on QoS metrics. To achieve good results,
CODECs behaviour is tested by using mobility information obtained from vehicular traffic generator. The
mobility model is based on the real road maps of an urban environment. Focusing on inter-vehicular
voice traffic quality, we provide simulations results in terms of both user level (MOS) metrics and
network level (such as Losses). According to this performance evaluation, we show that G.723.1 CODEC
worked well in the urban VANET environment.

Black hole and Grey hole attack is most happening attacks in Mesh networks. Mesh networks means nonstatic networks with making loops of networks with the help of active hotspots. In Wireless networks all the communication between the... more

Black hole and Grey hole attack is most happening attacks in Mesh networks. Mesh networks means nonstatic networks with making loops of networks with the help of active hotspots. In Wireless networks all the communication between the nodes is happening wirelessly and the nodes are so much resource constraint that it is difficult to employ any security solutions of other ad hoc networks. So they are attacked by malicious nodes. In black hole attack the attacker windup all the information and dropped it. In black hole attack, the series of RREQ (route request) and RREP (route reply) follows the smallest way of networking communication. The fault node always transmit RREP message as it receives RREQ, while managing the receivers sequence number. By the help of fault node packets are dropped. Sometimes fault node is authorised and otherwise it is unauthorised. Black hole attack is type of routing attack and can bring harm to whole network. Grey hole attack is the kind of denial of service attack. In this attack, the router which is mesh behave just not well and a subset of packets are forward and handle by receiver but leave by others. The presences of these attackers are hard to detect in wireless networks because over the wireless link the packets are lost due to bad channel quality. This paper deals with the study of analysis of delay occurs by these attack in Wireless Mesh networks and its types and also discuss about previous study by which we get idea about attack occurs in networks and also study various techniques to detect and prevent network from black hole and grey hole attack. Then we discuss about their result by using simulator OPNET.

Mobile Ad-hoc Networks (MANETs) are independent systems that can work without the requirement for unified controls, pre-setup to the paths/routes or advance communication structures. The nodes/hubs of a MANET are independently controlled,... more

Mobile Ad-hoc Networks (MANETs) are independent systems that can work without the requirement for unified controls, pre-setup to the paths/routes or advance communication structures. The nodes/hubs of a MANET are independently controlled, which permit them to behave unreservedly in a randomized way inside the MANET. The hubs can leave their MANET and join different MANETs whenever the need arises. These attributes, in any case, may contrarily influence the performance of the routing conventions (or protocols) and the general topology of the systems. Along these lines, MANETs include uniquely planned routing conventions that responsively as well as proactively carry out the routing. This paper assesses and looks at the effectiveness (or performance) of five directing conventions which are AOMDV, DSDV, AODV, DSR and OLSR in a MANET domain. The research incorporates executing a simulating environment to look at the operation of the routing conventions dependent on the variable number of hubs. Three evaluation indices are utilized: Throughput (TH), Packet Delivery Ratio (PDR), and End-to-End delay (E2E). The assessment outcomes indicate that the AODV beats other conventions in the majority of the simulated scenarios.

This paper investigates calendar anomalies for one emerging stock market (Bulgaria) and its matured counterpart in the Balkan region (Greece) during the period 2002 – 2008. Five popular calendar effects on both mean and variance are... more

This paper investigates calendar anomalies for one emerging stock market
(Bulgaria) and its matured counterpart in the Balkan region (Greece) during the period
2002 – 2008. Five popular calendar effects on both mean and variance are examined; the
day of the week effect, the January effect, the half month effect, the turn of the month effect
and the time of the month effect. Most of the tested effects exist for Greece. On the other
hand, the effects for Bulgaria are limited and exist only in variance. This contradictory
evidence could be due to different levels of liquidity, capitalisation and maturity for these
markets.

As we know in Mobile Ad hoc network our Nodes are highly mobile. They move around the Network. Due to this network topology and number of neighboring nodes in each node frequently change. Movement of nodes from one to another network also... more

As we know in Mobile Ad hoc network our Nodes are highly mobile. They move around the Network. Due
to this network topology and number of neighboring nodes in each node frequently change. Movement of
nodes from one to another network also affect to the communication between them. As the number of nodes
increases complexity of MANET increases in various issues. Nodes within the cluster communicate directly.
However, nodes communicate outside the cluster through a centralized node that is called a Cluster Head
Gateway (CHG) [1]. Ad hoc wireless network is a dynamic multi-hop network, which is established by a
group of mobile nodes on a shared wireless channel. The shared medium and the multi-hop nature of the
wireless ad hoc networks pose fundamental challenges to the design of an effective resource allocation
algorithm to maximize the aggregated utility of flows, maintaining basic fairness among the multiple flows.
An elected Cluster Head Gateway (CHG) is assigned for communication with all other clusters. The
centralized Cluster Head Gateway can become a bottleneck and possibly cause a lower connectivity for the
clustering system. In this paper we propose a mechanism in which communication outside the cluster is
distributed through separate Cluster Head Gateways with appropriate routing protocols. Here considering
are AODV, DSR, OLSR and TORA routing protocols. We are comparing protocols behaviour on the basis
of following parameters: delay, throughput, traffic sent, traffic received, data dropped and network load
and then check who is giving better performance. Finally, this paper conducts simulation experiments in
the conditions where we are using Multiple CHG to the nodes within a network

Multi Point Relays (MPRs) are those nodes that are calculated and determined by the Optimized Link State Routing protocol (OLSR) in order to minimize and avoid overload inside the Mobile Ad hoc Network (MANET). In this paper, we will... more

Multi Point Relays (MPRs) are those nodes that are calculated and determined by the Optimized Link State Routing protocol (OLSR) in order to minimize and avoid overload inside the Mobile Ad hoc Network (MANET). In this paper, we will present a synthetic study of many techniques and methods for calculating and selecting the MPR nodes using a set of criteria namely energy, mobility, bandwidth, the quality of links, etc. The result of this study shows that most techniques consider a limited number of metrics for selecting the MPR nodes and therefore they are insufficient to allow the OLSR protocol to be quite complete and efficient because several metrics can occur at the same time in the real execution environment. 1. INTRODUCTION The OLSR (Optimized Link State Routing) is a proactive routing protocol dedicated to MANET networks (Mobile Ad hoc Network) for establishing paths between network nodes. The routing process of this protocol is mainly based on the MPR (Multi Point Relay) selection technique in order to reduce the traffic load of the network and also to minimize the path to the destination [1, 2]. the MPRs search procedure launched by the NPC (Node Performing the Computation) makes it possible to detect a set of nodes able to transmit its messages and its data to other nodes far from its range and therefore cover the entire network. The computation of the MPR by the standard algorithm RFC3626 [3] presented below remains basic and insufficient because it does not take into account all the characteristics of the node and the network, for a thorough study of this problem we compared several approaches proposed by researchers in order to improve the quality of service [4, 5] and security level [6, 7] of this protocol against attacks [8, 9]. In the next section, we will present a brief description of a set of OLSR improved versions and approaches especially the MPRs selection technique, then in the third section, we will draw up a summary table of the comparative study and finally, we will conclude our study by analyzing the obtained results.

For next generation wireless networks, supporting quality of service (QoS) in multimedia application like video, streaming and voice over IP is a necessary and critical requirement. Wireless Mesh Networking is envisioned as a solution for... more

For next generation wireless networks, supporting quality of service (QoS) in multimedia application like
video, streaming and voice over IP is a necessary and critical requirement. Wireless Mesh Networking is
envisioned as a solution for next networks generation and a promising technology for supporting
multimedia application.
With decreasing the numbers of mesh clients, QoS will increase automatically. Several research are
focused to improve QoS in Wireless Mesh networks (WMNs), they try to improve a basics algorithm, like
routing protocols or one of example of canal access, but in moments it no sufficient to ensure a robust
solution to transport multimedia application over WMNs.
In this paper we propose an efficient routing algorithm for multimedia transmission in the mesh network
and an approach of QoS in the MAC layer for facilitated transport video over the network studied.

Wireless sensor networks are challenging networks regarding communication because of its resource constrained nature and dynamic network topology. Plenty of research has being going on throughout the world to optimize communication cost... more

Wireless sensor networks are challenging networks regarding communication because of its resource constrained nature and dynamic network topology. Plenty of research has being going on throughout the world to optimize communication cost and ...

In the design of mobile ad hoc networks, a challenging problem is how to route information reliably and efficiently from one node to another in moderate to high level of mobility. Due to mobility, limited residual energy of the node,... more

In the design of mobile ad hoc networks, a challenging problem is how to route information reliably and efficiently from one node to another in moderate to high level of mobility. Due to mobility, limited residual energy of the node, selection of stable and durable path for the communication is the challenge. Also remaining queuing capacity is also affected on the packet loss. Many proposals have been addressed to this problem; however, few papers consider a proactive protocol like Optimized Link State Routing Protocol (OLSR) to better manage the energy consumption and link stability in routing path selection algorithms. In this paper, we explored modification to MPR selection and integrating appropriate routing metrics in the routing decision scheme to lessen effects of reason that lead to more packet loss. Our power-aware version of OLSR is proven by simulations in NS3 under a range of different mobile scenarios and network density. Significant performance gains are obtained in terms of packet loss ratio and MPR count for our modified OLSR version.

Lately, many researchers have focused on implementing the Wireless Sensor Networks (WSNs) in medical applications. However, Wireless Body Area Networks (WBANs) promise to revolutionize health care in the near future. WBAN medical... more

Lately, many researchers have focused on implementing the Wireless Sensor Networks (WSNs) in medical applications. However, Wireless Body Area Networks (WBANs) promise to revolutionize health care in the near future. WBAN medical applications show great promise in improving the quality of life of people and satisfying many requirements of elderly people by enabling them to live safely, securely, healthily and independently. In this paper, we have simulated and analyzed well-known MANET routing protocols in WBAN of elderly long-term health monitoring system to determine which of them is much efficient to overcome MANET challenges in the medical applications. Various performance parameters used for comparison such as end-to-end delay, throughput, and packet loss ratio.