Performance Of Ad-hoc Networks Research Articles

Analysis of link time in Mobile Ad-Hoc Networks (MANET)

In the past decade, a steady increase has been noticed in the number of mobile users and the use of mobile communication. In wireless communication links are stable. Duration of the link is the most important design by which the performance of the mobile Ad Hoc network (MANET) can be determined. In this research article, a derivative metric of graph theory attained from mobility model technique in Ad Hoc network of casually moving object, link duration of probability density function (PDF)been examined by using three mobility models namely random waypoint, random direction, and freeway model. The performance is based on the node speed, transmission range, the density of node, area of simulation, and computational complexity with time. By using Monte Carlo simulations, the reliability and robustness of models have been analyzed. The main advantage of the proposed scheme is implemented is an easy hardware platform because of the concept in mobility models and the easiness of code.

Evaluating the Impact of Thermal Noise on AODV, DSDV and DSR Routing Protocols in Mobile Ad-hoc Networks

Because of their good support and easy deployment, wireless ad-hoc networks are currently widely being used for many industrial or military applications. Like other communication networks, environmental conditions can have considerable impact on the performance of wireless ad-hoc networks. Temperature is a good example which results in thermal agitation of the charge carriers. Consequently, we should be able to precisely estimate the performance of these networks in various environmental conditions to see whether they satisfy our expectations or not before any deployment. Investigating the effect of Thermal noise on the routing performance of Wireless Ad-hoc Networks is something never done before. This paper evaluates the impact of Thermal noise on the routing capability of Mobile Ad-hoc Networks (MANETs); which are a kind of Wireless ad-hoc Networks; in existence of thermal noise. The results can be a useful guidance for outdoor implementation of MANETs for industrial process automation and control applications.

Performance Evaluation of the IBETX Routing Metric Over DSDV Routing Protocol in Wireless Ad hoc Networks

Wireless ad-hoc networks are characterized by a collection of wireless mobile nodes that dynamically form a temporary network without the use of any pre-defined network infrastructure or centralized administration. They have attributes such multi-hop wireless connectivity, continuously changing topology and easy deployment. The increasing demands that are made by users pose a challenge in the improvement of the quality of wireless ad-hoc networks. The performance of wireless ad-hoc networks depend on the efficiency of routing protocols, especially the routing metric operating within it. In this paper, the performance of the recently proposed routing metric Interference Bandwidth Adjusted Expected transmission count (IBETX) metric is compared with two prominent existing metrics, the Expected transmission count (ETX) and the Inverse Expected Transmission count (InvETX) over the Destination Sequenced Distance Vector (DSDV) routing protocol. The performance differentials are analysed using varying packet rates and node densities. From the simulations results, IBETX metric outperforms the ETX and InvETX metric because it implements the bandwidth sharing mechanism and makes use of the information available at the MAC layer. It can also be noted that it is very sensitive to data traffic rate. It performs well in low and medium node densities.

Application of 3GPP LTE and IEEE 802.11p Systems to Ship Ad-Hoc Network with the Existence of ISI

In order to provide high data rate and real time services under maritime environment, link-level performance of ship ad-hoc network (SANET) based on 3GPP LTE and IEEE 802.11p (WAVE) specifications are investigated and discussed in this paper. The measured maritime channel, whose delay spread is longer than the length of guard interval (GI) of both 3GPP LTE and IEEE 802.11p specifications, is adopted for the link-level simulations. For the purpose of eliminating inter-symbol interference (ISI) due to insufficient GI length, double antenna pattern (DAP) scheme and advanced time-domain decision-feedback equalizer (DFE) are proposed for LTE and WAVE systems, respectively. The proposed DFE removes the ISI in a same manner as the residual inter-symbol interference cancellation (RISIC) algorithm, but the inter-carrier interference (ICI) is reduced via cyclicity removal instead of cyclicity restoration used in the RISIC algorithm. Compared with existing schemes, our proposed DFE is a robust technique to overcome the severe ISI channel which has a comparatively large delay spread. Based on simulation results, not only comparisons between systems are discussed, but also some reformative suggestions are given.

A Cross Layer Protocol for Improving the Performance of Ad Hoc Networks

To implement the cross layer protocol for improving the performance of multi-hop wireless network by routing, scheduling the transmission and traffic management. Unicast and multicast routes are established in coordination with the scheduling of transmissions and bandwidth reservations in a way that bandwidth and delay guarantees can be enforced on a per-hop and end-to-end basis. It establishes and maintains loop-free routes from sources to destinations. Traffic management is done by priority based queuing system. In addition, the routing algorithm establishes enclaves, which restrict the spread of control information to those nodes that are likely to participate as forwarders of a given data flow, rather than the entire network. Performance achieved by reducing the end-to-end delay, efficient packet delivery and reducing the communication overhead. By Simulation, comparing the existing protocols, this protocol attains better performance for elastic traffic, less delay and effective data delivery with less communication overhead. Further more, performance can be enhanced by scheduling the transmission more efficiently using token bucket filter scheme.

Area Partition-Based Suppression Algorithm for Contention-Based Forwarding in Mobile Ad-Hoc Networks

Contention-Based Forward (CBF) has proven to achieve a very good performance in mobile ad-hoc networks. Compare with other greedy forward algorithm, CBF is much more robust and have low maintenance network overheads. On the other hand, the main issue of CBF is to avoid packet duplication. Duplication is very easy to occur due to the hidden nodes problem. In this paper we introduce an area partition-based suppression algorithm for CBF in mobile ad-hoc networks. This algorithm sets the transmission area of a node into two areas: suppression area and none-suppression area. In the none-suppression area, the algorithm still use the SS-CBF (Sender Suppression-CBF) algorithm, in the suppression area, this paper will use a new equation to avoid packet duplication. The result shows that the new protocol could reduce the network overheads and do not cost extra transmission time.

Clustering Wireless Sensor and Wireless Ad Hoc Networks using Dominating Tree Concepts

The most important criterion for achieving the maximum performance in wirless sensor and ad-hoc networks is to clustering the nodes. Many clustering schemes have been proposed for different ad-hoc networks. In sensor networks the energy stored in the network nodes is limited and usually infeasible to recharge. The clustering schemes for these networks therefore aim at maximizing the energy efficiency. In mobile ad hoc networks the moment of the network nodes may quickly change the topology resulting in the increase of the overhead message in topology maintenance, the clustering schemes for mobile ad hoc networks therefore aim at handling topology maintenance, managing node movement or reducing overhead. In this paper we proposed an algorithm which gives connected dominating set of a tree.

The Spectral Efficiency of Slotted CSMA Ad-Hoc Networks with Directional Antennas

The performance of wireless ad-hoc networks (WANET) is mainly limited by its self-interference. This interference can be mitigated by applying smart access mechanisms and smart antennas. In this paper we analyze the performance of WANETs applying two-phase slotted carrier sense multiple access (CSMA) mechanism and utilizing directional antennas. We present simple expressions that enable a high accuracy evaluation of the network area spectral efficiency (ASE). The results show that directional antennas only affect the ASE through a scaling factor, which depends on the antennas pattern and the channel path loss. The ASE expression also provides a simple and accurate evaluation of the optimal system parameters, including the optimal network density, interference threshold and users' rates. In particular, the ASE gain for a CSMA WANET over an ALOHA WANET is shown to be approximated very well by the exponent of the back-off probability. The accuracy of the results and the usefulness of the optimization procedure are also illustrated through numerical simulations.

Impact of Rate Control on the Performance of a Cognitive Radio Ad-Hoc Network

Location awareness allows to define a concurrent transmission region where a primary and a secondary networks can coexist. In this paper we investigate the impact of channel rate control on the performance of a cognitive radio ad hoc network overlaying an infrastructure-based system. The proposed algorithm adequately adjusts the secondary user rate to be as large as possible while respecting a given constraint on the achievable primary rate. As a consequence, the rate control scheme expands the concurrent transmission region and increases the average rate of the secondary users, without affecting the primary. Numerical results show that it is possible to increase the throughput of the cognitive ad-hoc network and therefore increase the efficiency of the spectrum utilization.

A Study of Ad Hoc Network Performance in Disaster Response

Management problems are prevalent within ad hoc networks of public and nonprofit organizations that engage in disaster relief. This study explores the enabling factors that have an impact on the performance of public-nonprofit networks during disaster response and outcome factors that are influenced by the network performance. A survey is conducted among 288 disaster managers and analyzed by Partial Least Squares (PLS). The analysis reveals that a general openness to collaborate, collaboration experience, mutuality, and coordination have a strong impact on the performance of public-nonprofit networks. The network performance highly influences the long-term outcomes of a disaster response. The whole network of organizations can be strengthened and single organizations can acquire new knowledge. The results of this study help to derive implications for the management of public and nonprofit organizations active in disaster management operations.

A Simple but Efficient Scheme for Reliable Connectivity and High Performance in Ad-hoc Wireless Networks

This paper presents a simple but efficient scheme incorporating a reputation-based approach and a cross-layer approach, called the SIM scheme, for maintaining reliable connectivity and high performance in ad-hoc wireless networks. The SIM scheme incorporates the following two things: an ad-hoc routing scheme with a reputation-based approach exploiting the game theory concept based on an evolutionarily stable strategy, and a cross-layer approach between the network layer and the transport layer employing a reputation-based approach.

Decentralized Detection in Ad hoc Sensor Networks With Low Data Rate Inter Sensor Communication

Decentralized binary detection problem in ad-hoc sensor networks where a link between two sensors is on with a certain probability is considered in this paper. We propose a consensus based detection scheme where sensors exchange their local decisions, update their own decisions based on the exchanges and finally reach a consensus about the state of nature. We analyze the error probability and convergence of this decision consensus scheme. We show that with our scheme, the detection performance in ad-hoc networks is asymptotically equivalent to that of a parallel sensor network where all the local decisions are processed by a central node (fusion center) in the sense that the error exponents are the same. The probability distribution of the consensus time is also studied. Simulation and numerical results are given to verify the theoretical results.

Improving Energy Efficiency and Network Lifetime of Manets Through Ec-Mac Protocol

A MANET is an ad hoc network that can change locations and configure itself, and use wireless connections to connect various networks. The performance of Mobile Ad Hoc Networks (MANETs), is improved using Energy Conservation-MAC Protocol along with DEL-CMAC Protocol in terms of energy efficiency and network lifetime. This can be achieved through LZW (Lempel,Ziv and Welch) compression technique. The best relay selection strategy is incorporated, which selects the best relay based on residual energy and location information. To improve the spatial reuse and an innovative NAV (network allocation vector) setting is provided to deal with the varying transmitting power of the source and relay terminals. It provides the best selection algorithm to select the cooperative node with better channel condition, higher transmission rate, best relay and more balanced energy consumption.

Prepare Tone: Enhancing Broadcast-Packet Transmission of Multiple Rendezvous Mac Performance in Multiple-Channel Ad Hoc Network

Multiple Rendezvous approaches utilized multi-channel which was only with a single transceiver radio may enhance Mac throughputs of multi-channel ad hoc network no less than that of other approaches which need extra radios or hardware for time synchronization. However, for the media-access methods of Multiple Rendezvous, nodes in ad hoc network should be listening on different channels to preserve the control packets of any data transmission with noneinterference each other. Therefore, for any broadcast data packet or multicast data packet, it should be transmitted to its destinations like a set of single-cast data packets. And then other performances of ad hoc network as routing may be reduced by the high overload of broadcast packet. In order to reduce the transmission number of a broadcast packet, a method of using prepare tones (single-cast tone and broadcast tone) before data-packet transmission is presented, we called it PTMC (Prepare Tone for Media-access Control). In the method of PTMC, any broadcast packet will be send out only once to preserve it can reach any idle destination, which is not sending or receiving any data-packets at that time, nevertheless any single-cast packet will be matched and send out just as MAXM done. Simulation results among PTMC, MAXM and SSCH show: If every broadcast packet was send to potential receivers one by one, the throughputs of ad hoc network routed by AODV and media controlled by MAXM or SSCH may not be improved as the available channel number is increasing, for reasons of the routing discovery time increasing. Using PTMC to solve this problem, whatever data-traffics or available channels are provided, the throughput of PTMC will be better than the other two. Thus with available channels increasing, the throughput of PTMA is improved.

Stitching Algorithm: A Network Performance Analysis Tool for Dynamic Mobile Networks

The performance analysis of the mobile ad-hoc network (MANET) is a challenging issue. In this paper, network tomography is studied to analyse the network performance in a dynamic MANET. For such a purpose, a network tomography analytical model is proposed for a dynamic network environment. Expected Maximization (EM) algorithm for network tomography is able to estimate the network performance parameter in accordance to network performance observations. Our study is different than current network tomography approaches where are applied for static wired network. Over the dynamic network, we proposed a new algorithm that is called Stitching algorithm to aggregate the dynamic performance. Specifically, the stitching algorithm concatenates the performance parameter i.e. link delay, from distinguish time periods. Therefore, the network behaviour as well as the corresponding performance in a mobile ad-hoc network can be derived over a continuous period.

Impact of Correlated Mobility on Delay–Throughput Performance in Mobile Ad Hoc Networks

We extend the analysis of the scaling laws of wireless ad hoc networks to the case of correlated nodes movements, which are commonly found in real mobility processes. We consider a simple version of the Reference Point Group Mobility model, in which nodes belonging to the same group are constrained to lie in a disc area, whose center moves uniformly across the network according to the i.i.d. model. We assume fast mobility conditions and take as a primary goal the maximization of per-node throughput. We discover that correlated node movements have a huge impact on asymptotic throughput and delay and can sometimes lead to better performance than the one achievable under independent nodes movements.

Design and Performance Analysis of Underwater Acoustic Networks

We analyze the performance of underwater acoustic ad-hoc networks in the presence of interference. We assume a uniform distribution of nodes over a finite area, and focus for simplicity on a two-dimensional network. The node-to-node channel is modeled using frequency dependent path loss and Ricean fading. We adopt a communication theoretic approach and study the sustainable number of hops through the network as an indicator of the network connectivity, as well as power and bandwidth requirements. The network operation is highly dependent on the node density with two distinct regions of limited performance: the coverage-limited region, where the number of nodes in the network is small, and the interference-limited region, where the number of nodes is large. We show that a desired level of connectivity can be achieved through a judicious selection of the operating frequency, power and bandwidth. Numerical examples illustrate the results of the analysis. These results motivate us to propose a hierarchical underwater acoustic sensor network architecture in which the sensors and the collector stations operate in distinct layers. The hierarchical architecture is supported by the property of the acoustic underwater transmission medium that for each transmission distance there exists an operating frequency for which the narrow-band signal-to-noise ratio is maximized. The sensors and the collector stations are consequently allocated different operating frequencies. We assume a uniform distribution of both sensors and collector stations over the finite area of the sensing field, and model the channel accordingly. The analysis is performed under the assumption that there is interference from other nodes within the same layer of the hierarchy. Numerical examples illustrate the network performance and demonstrate that the preferred operating frequencies ensure network operation without any cross-interference between the collector network and the sensor network.

Experimental Analysis of UDP Performance in Mobile Ad Hoc Networks with Different Routing Protocols and varying payload

The purpose of this paper is to investigate the performance of UDP over various routing protocols in ad hoc networks. For this investigation we have chosen three routing schemes, DSDV, DSR and AODV and four network scenarios of 4, 8, 16 and 32 nodes of various node mobility speeds. Results are produced by evaluating throughput and end to end packet delay over the UDP connection through simulation experiments.

Movement Control Algorithms for Improving Topology Control Performance in Ad Hoc Networks

在无线Ad Hoc 网络中,拓扑控制算法能够使节点的传输功率小于最大传输功率,从而可以节省网络能量,提高网络容量.由于节点分布的随机性,在节点较为稀疏的区域,拓扑控制算法存在着局限性,因而提出了移动控制算法来改善拓扑控制算法的性能.在保证网络连通性的前提下,算法首先根据收集到的信息,通过构造网络最小生成树确定较长的通信链路,并移动网络中的部分节点使这些链路缩短,从而显著减小网络中较大的通信半径,提高了拓扑控制的性能.仿真实现了PMST-P,PMST-UV和LMST-LUV 这3 种移动控制算法,并对它们的性能进行了讨论和相互比较.;In Ad Hoc networks, topology control is designed to save energy and increase network capacity by enabling nodes to use proper transmission power, which is usually much smaller than the maximal transmission power. However, the randomicity of network deployment and node movement results in a non-uniform distribution of nodes. In a region where nodes are sparse, the distance between two nodes may be much longer than that in a dense region, so the transmission power is not able decrease and does not depend on which topology control algorithm is adopted. For the first time, this paper proposes movement control algorithms to improve performance of topology control by moving a subset of nodes to desiring positions. Based on the minimum spanning tree of the network topology graph, addition links are determined. Moreover, addition links are shortened and large communication range may be reduced by moving some nodes. Three movement algorithms, PMST-P, PMST-UV and LMST-LUV, are realized, and their performance is compared with each other with respect to maximum communication range, total moving distance and etc. using simulations.

Two Relay Strategies in Multi-Node Cooperative Communications in Ad-Hoc Networks

In this patent, we propose and compare two different relaying strategies in cooperative communications involving channel coding, network coding and turbo decoding in a wireless Ad-Hoc network scenario. A wireless Ad-Hoc Network is a decentralized network where each node can join the cooperative communication as a relay by decoding and forwarding data from other nodes to the destination. In this work multiple nodes send data to the destination with the assistance of a single relay node where the decode-and-forward (DF) protocol is adopted. One relay strategy uses network coding after the relay successfully receives and decodes information frames from all source nodes. The other strategy uses recursive systematic convolutional (RSC) channel coding at the relay for the interleaved, decoded information steams from all source nodes. At the destination, turbo decoding is carried out for both schemes. We show through simulations that both methods have a fast turbo decoding convergence within two or three iterations. The second one provides a better performance when the signal-to-noise ratio in the relay link is relatively high. However, in the case where the relay link is weak, the first one with network coding outperforms. This result indicates that different channel conditions require different relaying strategies and a proper switch between strategies in the relay may improve the overall performance of Ad-Hoc networks.