Impact Of Node Mobility Research Articles

Impact of node mobility on the DL based uplink and downlink MIMO-NOMA network

Impact of node mobility on the DL based uplink and downlink MIMO-NOMA network

Adaptive AF/DF Two-Way Relaying in FD Multiuser URLLC System With User Mobility

We consider a full-duplex (FD)-enabled multi-user two-way communication system with adaptive amplify-and-forward (AF)/decode-and-forward (DF) relaying protocol. All the users are assumed to be mobile and to have FD abilities. The effect of mobility, which results in time-selective fading, is modeled using a first-order autoregressive (AR1) process. The fading channel-based approach characterizes the residual self-interference (RSI) at the FD relay, user nodes and is modeled as a Rician distributed random variable. This paper constitutes the most critical use case of 5G, i.e., ultra-reliable low latency communication (URLLC), which adopts short-packets finite blocklength (FB) codes to spin out into the mission-critical applications where strict latency and reliability requirements are highly desirable. The outage performance of the system is studied over independent and non-identically distributed complex Gaussian (Rayleigh envelope) channels with imperfect channel state information (CSI) for with and without URLLC use cases. The closed-form expressions for the outage probability and block error rate (BLER) are derived for the absolute channel power-based scheduling scheme considering the different Doppler power spectra models and the effect of co-channel interference (CCI). The expressions for the asymptotic outage probability are also derived. The presented analysis is compared with baseline schemes, e.g., the results derived with adaptive AF/DF relaying are also compared with both AF and DF relaying, and the performance of the FD transmissions is compared to that of half-duplex (HD) transmissions. The impact of node mobility, RSI, FBL, number of user pairs, and imperfect CSI on the system performance is investigated. Moreover, essential insights are obtained related to the performance gain and region of the superiority of the adaptive AF/DF relaying scheme. The derived analytic results are validated through Monte Carlo simulations. Furthermore, at high transmit power, the outage performance for the adaptive AF/DF protocol approaches the derived asymptotic floor.

Multivariate fuzzy logic‐based ad hoc on‐demand distance vector protocol under the impact of node mobility in wireless ad hoc networks

SummaryEfficient routing of generated packets through the network with minimal overhead in path discovery and subsequent route maintenance is the fundamental objective required in the modern wireless network operation. Recently, the application of autonomic computational learning techniques for design and optimization of routing protocols in ad hoc networks is substantially gaining the research interest. The commonly deployed soft computing methodology of fuzzy inference system is capable of handling uncertain and imprecise networking information related to the frequently changing states of generic mobile technologies. In this paper, we propose a novel fuzzy logic‐based ad hoc on‐demand distance vector (FL‐AODV) routing protocol employing the multivariate cross‐layer design architecture to optimize the multiple performance parameters in wireless ad hoc networks. This fuzzy optimization framework essentially applies the header length from data link and physical layers, route timeout from network layer, and node mobility speed from application layer as inputs to the fuzzification interface. Besides, bit rate for application layer and communication range parameter for data link layer are scrutinized as the fuzzy outputs derived from the defuzzifier. The designed adaptive routing protocol is extensively assessed through simulation experimental analysis under the varying effects of node mobility conditions. Various network performance attributes including the reception cache hit, packet delivery ratio, packet errors, ping loss rate, mean throughput, and delay are computed and analyzed for comprehensive comparison between the presented fuzzy‐based FL‐AODV and classical AODV routing mechanisms. Finally, we compare our fuzzy routing model with previous algorithms to demonstrate its efficacy in terms of key performance metrics of throughput and delay.

Improvising packet delivery and reducing delay ratio in mobile ad hoc network using neighbor coverage‐based topology control algorithm

SummaryMobile ad hoc network (MANET) is an infrastructure‐less network. Every Node act as a sender as well as receiver while sending a packet. Neighbor coverage probabilistic rebroadcasting (NCPR) protocol plays a momentous role in MANET for determining a route by helping the transitional nodes to onward a packet when the mobile nodes are not in the transmission space. This protocol minimizes the interference among node and increases the network capacity. There occurs a delay in the network while sending a packet via failure route or channel. Before sending a packet in the network, all the neighbor nodes have to be verified to avert congestion in the network. Quality of service (QoS) plays an important role in the development of MANET. In this research work, delay and neighbor connectivity‐based constrain is focused. The impact of node mobility during interference and delay is examined using network coding‐based topology control algorithm. By using this algorithm, irrelevant links are identified and detached from the topology. The simulation result shows that neighbor coverage established topology control algorithm for delay (NCTCAD) can reduce the delay and upturn the performance in MANETs.

Exploring the Impact of Node Correlation on Transmission Reuse in MANETs

The main advantage of multicast over multi-unicast is the existence of transmission reuse, i.e., the cooperation among destinations. This intrinsic characteristic benefits the multicast regarding the enhancement of transmission efficiency. Consequently, multicast is extensively studied under various wireless environments. Yet people still have limited understanding on the impact of node mobility on the transmission reuse when multicast is applied instead of multiple unicast. In this paper, we focus on the correlated mobility which captures the feature of real mobility processes, to study its influence on transmission reuse in mobile ad hoc networks (MANETs). Specifically, we quantify the transmission reuse as multicast gain , i.e., the capacity ratio of multicast and multi-unicast under certain delay constraint. We design a multi-layer routing protocol and propose different kinds of causal scheduling policies, under which the overall multicast capacity-delay tradeoff is derived by exploring various correlation degrees of node mobility. Compared with the capacity-delay tradeoff in unicast case, we calculate the multicast gain. Results show that the correlation of node mobility greatly influences the multicast gain, and in certain cases network can achieve the upper bound of multicast gain regardless of the logarithmic factor.

Assessing node mobility impact on routing performances in MANETs

Mobile ad hoc network (MANET) plays a major role in enabling data communication in infrastructures-less areas. Network performance relies on the capacity of mobile nodes to process data packet and deliver it to the right destination at lower cost. Since nodes are free to move toward random destination, data delivery from a source to a destination might be disturbed due to frequent topology changes. Hence, mobility in mobile ad hoc network represents the main issue that should be addressed carefully while designing routing protocols. The purpose of this paper is to study the impact of node mobility on the performance of well-known routing protocols such as destination-sequenced distance vector (DSDV), dynamic source routing (DSR) and ad-hoc on demand distance vector (AODV). We assessed the efficiency of each protocol under high mobility environment using various values of speed and pause. Performance assessment is based on the conventional metrics such as latency, throughput, packet delivery ratio (PDR) and routing overhead. Moreover, we introduced two new metrics called path change factor (PCF) and route repair influence (RRI) for accuracy purpose. The study demonstrates that AODV has better performances in high mobility environment.

On QoS evaluation for ZigBee incorporated Wireless Sensor Network (IEEE 802.15.4) using mobile sensor nodes

The design of an efficient and scalable Wireless Sensor Network (WSN) to accommodate the fluctuations in topology, node-mobility, node-density, and network-size is an exigent task. A meticulous investigation is necessitated to implement the sensor nodes in an appropriate topology at optimum node-mobility in ZigBee incorporated WSN networks to offer optimum Quality of Services (QoS). Subsequently, an attempt to compute the comprehensive recital of a non-beacon mode based 802.15.4/ZigBee integrated WSN network is demonstrated. An analytical model is designed using parameters such as back-off number, retransmission limit, and back-off exponent considering the impact of node-mobility which has not reported earlier. Further, the investigation is carried out experimentally by evaluating the different QoS metrics, for instance, throughput, network load, bit error rate (BER), received power, signal to noise ratio (SNR) and end-to-end delay for diverse node-density and network-size of a mobile Wireless Sensor Network. Based on the measurements obtained, the authors recommend implementing the mobile sensor nodes in a cluster-tree fashion to afford the best possible QoS services.

Joint impact of nodes-mobility and channel estimation error on the performance of two-way relay systems

This paper presents the performance analysis of a two-way relay system with nodes-mobility (NM) and channel estimation errors (CEE) under time-varying Rayleigh fading. Herein, analog network coding protocol is employed at the relay node. All the participating nodes are half-duplex and equipped with single-antenna devices. Specifically, we utilize first-order Markovian model to characterize the impact of NM in the channel. Along with the NM, we also consider that the CEE may exist in practical scenarios, where nodes require to estimate the channel state information. By incorporating these factors, we first derive the instantaneous end-to-end (e2e) signal-to-noise ratios (SNRs) at two source nodes. Then, we obtain the exact closed-form expressions for distribution and density functions of the two e2e SNRs. After that, we derive the accurate expressions of various performance metrics, viz., sum-bit error rate, overall outage probability, and ergodic sum-rate. Further, to attain more insights into the considered system, we deduce the asymptotic behavior of these performance metrics. Finally, numerical and Monte-Carlo simulation results are provided to validate our theoretical analysis and to illustrate the impact of NM and CEE on the performance measures of the considered system.

Impact of Node Mobility on MANETs Routing Protocols under Random Waypoint, Group and File Mobility Models

In present study, researcher has investigated the impact of node mobility by evaluating the performances of different routing protocols using mobility models. Detailed simulations were carried out, using QualNet simulator with varying node density. In the simulation study the Random Waypoint, Group and File mobility models were considered. Simulation results illustrated that, the performance of routing protocols significantly affect with the mobility models. Overall, the performance of various routing protocols is highly affected under the Random Waypoint mobility model than that of File and Group mobility models. It has happened because of frequent node movement under the Random Waypoint mobility model than that of other mobility models.

Interference-Based Topology Control Algorithm for Delay-Constrained Mobile Ad Hoc Networks

As the foundation of routing, topology control should minimize the interference among nodes, and increase the network capacity. With the development of mobile ad hoc networks (MANETs), there is a growing requirement of quality of service (QoS) in terms of delay. In order to meet the delay requirement, it is important to consider topology control in delay constrained environment, which is contradictory to the objective of minimizing interference. In this paper, we focus on the delay-constrained topology control problem, and take into account delay and interference jointly. We propose a cross-layer distributed algorithm called interference-based topology control algorithm for delay-constrained (ITCD) MANETs with considering both the interference constraint and the delay constraint, which is different from the previous work. The transmission delay, contention delay and the queuing delay are taken into account in the proposed algorithm. Moreover, the impact of node mobility on the interference-based topology control algorithm is investigated and the unstable links are removed from the topology. The simulation results show that ITCD can reduce the delay and improve the performance effectively in delay-constrained mobile ad hoc networks.

Oceanic forces and their impact on the performance of mobile underwater acoustic sensor networks

SummaryThis paper focuses on the performance analysis of Underwater Wireless Acoustic Sensor Networks (UWASNs) with passively mobile sensor nodes moving because of the influence of major oceanic forces. In an UWASN, passive node mobility is inevitable. Therefore, the performance analysis of UWASNs renders meaningful insights with the inclusion of a mobility model, which represents realistic oceanic scenarios. In this regard, the existing works on performance analysis of UWASNs lack the consideration of major dominating forces, which offer impetus for a node's mobility. Additionally, the existing works are limited to only shallow depths and coastal areas. Therefore, in this paper, we have proposed a physical mobility model, named Oceanic Forces Mobility Model, by incorporating important realistic oceanic forces imparted on nodes. The proposed model considers the effects of node mobility in 3‐D space of water. We also present an analysis on the impact of node mobility on the performance of UWASNs in terms of network dispersion and localization. Simulation results indicate performance degradation of UWASNs in the presence of oceanic forces—localization coverage decreases by 36.70%, localization error increases nearly by 21.14%, and average energy consumption increases by 3% approximately. Copyright © 2014 John Wiley & Sons, Ltd.

Using Trust to Secure Geographic and Energy Aware Routing against Multiple Attacks

To address the vulnerability of geographic routing to multiple security threats such as false routing information, selective forwarding and the Sybil attack in wireless sensor networks, this paper proposes a trust-based defending model against above-mentioned multiple attacks. Considering the characteristics of resource-constrained sensor nodes, trust values of neighboring nodes on the routing path can be calculated through the Dirichlet distribution function, which is based on data packets' acknowledgements in a certain period instead of energy-consuming monitoring. Trust is combined with the cost of geographic and energy aware routing for selecting the next hop of routing. At the same time, the initial trust is dynamically determined, service requests are restricted for malicious nodes in accordance with trust values, and the impact of node mobility is weakened by the trust evolution. The simulation results and analysis show that the proposed model under multiple attacks has advantages in packet delivery ratio and network lifetime over the existing models.

Mitigating the impact of node mobility using mobile backbone for heterogeneous MANETs

Routing in Mobile Ad hoc Network (MANET) has been an active research area in the past few years. It is observed that as the mobility of nodes increases, the performance of existing cluster based routing protocols tends to deteriorate rapidly. Although many mobility based clustering schemes have been proposed to address this problem, majority of these proposals assume the movement of nodes follows group mobility. In this paper, we propose a new cluster based routing protocol FASTR which utilizes mobile backbone to mitigate the impact of node mobility for networks with high node mobility and low group mobility. Our scheme eliminates the delay caused by cluster head election and enables nodes to start communication immediately after joining a cluster. Through simulation and analysis, our protocol is shown to possess good scalability, incur lower control overhead and achieve higher packet delivery ratio than existing OLSR and HOLSR routing protocols for various node mobility. Furthermore, unlike other proactive routing protocols, the control overhead of FASTR is shown to be independent of node mobility and consume less network resources than HOLSR and OLSR.

IEEE 802.11b based ad hoc networking and its performance in mobile channels

It is widely believed that IEEE 802.11 standard is aimed mainly for fixed indoor wireless local area networks and is not suited for mobile applications, even though the IEEE 802.11b systems may work in either infrastructure mode or ad hoc mode. The impact of node mobility on ad hoc network performance has already been studied intensively, but these studies mostly do not consider temporal fluctuations of the mobile wireless channel due to the Doppler shift. An investigation of the mobility impact on the performance of IEEE 802.11b ad hoc systems with Rician/Rayleigh fading under different node velocities is presented. A comprehensive and in-depth analysis of the impacts of a multitude of different signal distortions on an IEEE 802.11b system performance is also presented. Specifically, the authors study the bit-error rate performances with respect to node velocities for different modulation schemes. The simulation results show that, owing to its extremely low implementation and deployment cost, the current IEEE 802.11b standard has its potential to be deployed in a mobile ad hoc environment if the line-of-sight path between transmitter and receiver exists.

Distributed clustering algorithms for data-gathering in wireless mobile sensor networks

One critical issue in wireless sensor networks is how to gather sensed information in an energy-efficient way since the energy is a scarce resource in a sensor node. Cluster-based architecture is an effective architecture for data-gathering in wireless sensor networks. However, in a mobile environment, the dynamic topology poses the challenge to design an energy-efficient data-gathering protocol. In this paper, we consider the cluster-based architecture and provide distributed clustering algorithms for mobile sensor nodes which minimize the energy dissipation for data-gathering in a wireless mobile sensor network. There are two steps in the clustering algorithm: cluster-head election step and cluster formation step. We first propose two distributed algorithms for cluster-head election. Then, by considering the impact of node mobility, we provide a mechanism to have a sensor node select a proper cluster-head to join for cluster formation. Our clustering algorithms will achieve the following three objectives: (1) there is at least one cluster-head elected, (2) the number of cluster-heads generated is uniform, and (3) all the generated clusters have the same cluster size. Last, we validate our algorithms through an extensive experimental analysis with Random Walk Mobility (RWM) model, Random Direction Mobility (RDM) model, and a Simple Mobility (SM) model as well as present our findings.

A Method of Selecting Steady Path Based on Neighbor Change Ratio in Mobile Ad Hoc Networks

Node mobility is one of the dominant factors causing decreased performance in mobile ad hoc networks and restricting network scalability. Selecting stable paths is an effective way to reduce the impact of node mobility. Current methods of selecting stable paths in mobile ad hoc networks suffer from several shortcomings. They may need a hardware function support for geographical position location or cross-layer function support for sending signal strength information to upper layers. In this paper, a new method of selecting stable paths based on the neighbor change ratio is proposed. Neither the special hardware support nor the cross-layer support is needed in this new method. NCR-AODV (neighbor change ratio Ad hoc on-demand distance vector) routing protocol is an extension of the AODV (Ad hoc on-demand distance vector) on-demand route protocol with the new method. The new protocol selects the path which has smaller hop counts and less local topology changes to forward data. The simulation results show that NCR-AODV protocol decreases the long path break probability and improves the network performance.

Relaying in mobile ad hoc networks: The Brownian motion mobility model

Mobile ad hoc networks are characterized by a lack of a fixed infrastructure and by node mobility. In these networks data transfer can be improved by using mobile nodes as relay nodes. As a result, transmission power and the movement pattern of the nodes have a key impact on the performance. In this work we focus on the impact of node mobility through the analysis of a simple one-dimensional ad hoc network topology. Nodes move in adjacent segments with reflecting boundaries according to Brownian motions. Communications (or relays) between nodes can occur only when they are within transmission range of each other. We determine the expected time to relay a message and compute the probability density function of relaying locations. We also provide an approximation formula for the expected relay time between any pair of mobiles.