Random Waypoint Model Research Articles

IMPLEMENTATION AND OPTIMIZATION OF RWP MOBILITY MODEL IN WSNS UNDER TOSSIM SIMULATOR

Mobility has always represented a complicated phenomenon in the network routing process. This complexity is mainly facilitated in the way that ensures reliable connections for efficient orientation of data. Many years ago, different studies were initiated basing on routing protocols dedicated to static environments in order to adapt them to the mobile environment. In the present work, we have a different vision of mobility that has many advantages due to its 'mobile' principle. Indeed, instead of searching to prevent mobility and testing for example to immobilize momentarily a mobile environment to provide routing task, we will exploit this mobility to improve routing. Based on that, we carried out a set of works to achieve this objective. For our first contribution, we found that the best way to make use of this mobility is to follow a mobility model. Many models have been proposed in the literature and employed as a data source in most studies. After a careful study, we focused on the Random Waypoint mobility model (RWP) in order to ensure routing in wireless networks. Our contribution involves a Random Waypoint model (in its basic version) that was achieved on the TOSSIM simulator, and it was considered as a platform for our second (and main) contribution, in which we suggested an approach based RWP where network nodes can collaborate and work together basing on our recommended algorithm. Such an approach offers many advantages to ensure routing in a dynamic environment. Finally, our contributions comprise innovative ideas for suggesting other solutions that will improve them.

Performance Analysis of OLSR Protocol in Mobile Ad Hoc Networks

Optimized Link State Routing Protocol (OLSR) is an efficient routing protocol used for various Ad hoc networks. OLSR employs the Multipoint Relay (MPR) technique to reduce network overhead traffic. A mobility model's main goal is to realistically simulate the movement behaviors of actual users. However, the high mobility and mobility model is the major design issues for an efficient and effective routing protocol for real Mobile Ad hoc Networks (MANETs). Therefore, this paper aims to analyze the performance of the OLSR protocol concerning various random and group mobility models. Two simulation scenarios were conducted over four mobility models, specifically the Random Waypoint model (RWP), Random Direction model (RD), Nomadic Community model (NC), and the Reference Point Group Model (RPGM) with a low as well as high random range mobility of the nodes. Moreover, BonnMotion Software and Network simulator NS-3 used to implement the simulation scenarios. Further, the performance of the OLSR protocol analyzed and evaluated based on latency, routing overhead, and packet loss ratio metrics. According to the results, the OLSR protocol provides the best performance over the RWP model in a low mobility environment, whereas the Nomadic mobility model is suitable for OLSR protocol in a high mobility environment.

Interference Distribution for Directional Beamforming Mobile Networks

In this paper, we model the aggregate interference power in directional beamforming mobile networks. The work considers the random waypoint model to describe the mobility of the nodes and adopts directional beamforming for communication. The major contribution of this paper is the statistical characterization of the aggregate interference caused by directional beamforming transmissions of mobile interferers to a given node positioned at a reference point. The analysis assumes Rayleigh and Rician small-scale fading channels, a distance-based path-loss large-scale fading model, and a three gain levels sectored antenna model. The quality of the proposed approximations has been confirmed through various simulations for different mobility scenarios, channel conditions, and beamforming parameters, highlighting the effect of directional communication along with mobility on the aggregate interference. To demonstrate the practical application of the work, we use two different estimators for the interference characterization. The results confirm the effectiveness of the estimators even when adopting a small set of samples.

On the Use of LoRaWAN for Mobile Internet of Things: The Impact of Mobility

A long-range wide-area network (LoRaWAN) targets both mobile and static Internet of Things (IoT) applications; it is suited to IoT applications, which require a large coverage area while consuming less power at a low data rate; it provides a solution for transferring data between IoT devices with a minimum cost in terms of power, at the expense of higher latency. LoRaWAN was designed for static low-power long-range networks. However, several IoT solution applications involve the use of mobility. Therefore, this study investigates the usage of LoRaWAN in the field of mobile Internet of Things applications such as bike rentals, fleet monitoring, and wildlife and animal tracking applications. Using the OMNeT++ simulator, two different well-known mobility models are used to investigate the influence of mobility on the performance of mobile LoRaWAN. The results show that intense LoRaWAN networks can operate under a high velocity and varying traffic load. It can be observed that the random waypoint model combination yields a better performance, but at the cost of higher collisions and energy consumption. As a consequence, the results suggest the reconsideration of mobile IoT solutions over LoRaWAN.

RWP+: A New Random Waypoint Model for High-Speed Mobility

In this letter, we emulate real-world statistics for mobility patterns on road systems. We then propose modifications to the assumptions of the random waypoint (RWP) model to better represent high-mobility profiles. We call the model under our new framework as RWP+. Specifically, we show that the lengths of the transitions which constitute a trip, are best represented by a lognormal distribution, and that the velocities are best described by a linear combination of normal distributions with different mean values. Compared to the assumptions used in the literature for mobile cellular networks, our modeling provides mobility metrics, such as handoff rates, that better characterize actual emulated trips from the collected statistics.

Performance of an Underwater Optical Wireless Link With a Randomly Placed or Moving Receiver

The current work investigates the outage probability of a vertical diffused line-of-sight underwater optical wireless communication link where a fixed transmitter at the sea surface communicates with a receiver floated below sea level, which may be still but randomly placed at a given location or moving following the random waypoint model. In both considered scenarios, the channel gain follows a random distribution making the problem mathematically challenging. Novel mathematical expressions are derived for the channel gain statistics for either random placement and mobility effects. Afterward, the signal-to-noise ratio statistics are extracted, assuming indirect modulation/direct detection at the receiver. Hence, the outage probability and the average bit-error-rate for on-off keying are readily calculated. Finally, some relevant numerical results are depicted in a series of figures to highlight the overall performance.

Physical layer security analysis of a dual-hop hybrid RF-VLC system

Abstract In this paper, we investigate the secrecy performance of a dual-hop hybrid radio frequency–visible light communication (RF–VLC) system in which we consider a single source antenna (S) transmitting data signals via RF channel through decode and forward (DF) relay (R) toward an authorized receiving antenna (D) at the destination via VLC channel. In this system, we assume that the eavesdropper (E) attempts to eavesdrop the RF channel (S,R) during transmission of the signal. The relay decodes the incoming RF signal into corresponding optical signal and retransmits toward destination via VLC channel (R,D). The RF and VLC channels of the hybrid system are modelled using generalized-K fading distribution and generalized Lambertian radiant intensity distribution respectively. Also the receiver is assumed to be mobile and its mobility is defined by random waypoint (RWP) model. The channels statistics are used to derive the exact analytical expressions for average secrecy capacity and intercept probability in terms of Meijer’s G-function. The derived closed form analytical expressions are the efficient tool to illustrate the impact of variation in different channel parameters on the secrecy performance, namely, shadowing parameters of RF channel, field of view (FOV), semiangle, and the order of Lambertian emission of the VLC channel. Further, numerical analysis is carried out to support the mathematical analysis of the RF–VLC hybrid system.

CEBD: Contact-Evidence-Driven Blackhole Detection Based on Machine Learning in OppNets

Blackhole detection in the opportunistic networks offers an effective means to mitigate the routing performance degradation but faces many challenges from corrupted nodes due to their collusion behaviors. Most existing effort in the literature focuses on the blackhole feature extraction from the message exchange. However, the decay effect of features and the forged features from the corrupted node, which acts as the rational node in performing message exchange, degrade the performance of the detection. In this article, we investigate the evidence construction, i.e., the direct and indirect evidence with the statistical parameters in message exchange. Specifically, we construct behavior classifiers to distinguish the blackhole behaviors from rational ones and design the collusion filtering strategy to improve the detection accuracy by separating corrupted nodes from rational ones, laying a behavior identification foundation. The contact evidence-driven blackhole detection (CEBD) based on machine learning is proposed to improve the routing performance. The soundness of the proposed scheme is verified statistically and the detection accuracy is evaluated based on random waypoint model (RWP) trace and Shanghai taxi trace. Extensive simulations show that our scheme outperforms the benchmarks, including SDBG, Li, and MDS, in terms of the delivery ratio in various scenarios.

On outage performance of IRS‐assisted wireless communication with user mobility following RWP model

An intelligent reflecting surface (IRS)-assisted wireless communication system with user mobility following random waypoint (RWP) model is investigated, where the user receives the reflection signal from the IRS controlled by the access point (AP) via a programmable controller, and the IRS is mounted on an unmanned aerial vehicle which is only an auxiliary device to enable IRS reflection communication at a certain altitude. As user moves, the AP makes the reflected beamforming of the IRS following with the user through coding the unit-element of the IRS. To investigate the effect of joint IRS feature and user mobility on the outage performance, the cumulative distribution function of the received signal-to-noise ratio of the mobile user is first derived and then the close-form expression for the outage probability is obtained. Numerical simulations are performed to validate the accuracy of the analytical results. The solutions are also compared with that for conventional amplify-and-forward relay system. Insights are drawn related to the number of meta-surface elements, and the maximum activity radius of mobile user.

Link discontinuity and optimal route data delivery for random waypoint model

In mobile ad hoc network (MANET), the traffic load impacts energy utilization and throughput. It can be overcome by efficient congestion control and link discontinuity identifier techniques. To improve the overall network performance of MANET, the link discontinuity and optimal route data delivery (LDORDD) protocol has been implanted based on AOMDV protocol is proposed along with cross-layer design. In this approach, local route recovery and transmission queue management (TQM) activities are used to control the packet's drop and congestion. This protocol works on buffering the incoming packets at the TQM layer, which controls the packets drop by locally repairing the route. The simulation results of the LDORDD protocol is evaluated in terms of network throughput, packet delivery ratio, and average end to end delay. The numerical and graphical representation of the LDORDD proves that the network resource rudiments are enhanced when compared to the existing methods.

Cooperative Spectrum Sensing using Mobile Full-Duplex Cognitive Radio and Non-time-slotted Primary user Activity

An In-band-full-duplex (FD) technology-empowered cognitive radio (CR) system with a non-time-slotted primary user activity is presented in this work. FD here means that the transmission and reception can be performed at the same frequency and time simultaneously. Moreover, to incorporate the mobility of the CR, the random waypoint model is used. The non-time-slotted primary user activity implies that the primary and the secondary network are not synchronized. Non-time-slotted means that the primary user can be active or inactive during the CR's sensing/transmission duration. In the conventional time-slotted model, the primary user changes its state during the initial time and not later in the CR sensing window. The performance of the considered FD-CR network is observed in a Rayleigh fading environment. Specifically, the expression for miss-detection probability is derived. It is observed that the CR mobility and non-time-slotted primary activity would very much affect the miss-detection probability. Also, the proposed system with an efficient self-interference suppression mechanism outperforms the conventional half-duplex CRN.

Evaluating the Mobility Impact on the Performance of Heterogeneous Wireless Networks Over η – μ Fading Channels

The 5G and beyond networks will intrinsically accommodate a wide range of use-case scenarios and expand the limit of legacy mobile systems. The 5G network architecture can handle the seamless operation of various wireless channels in a heterogeneous environment. The $\eta $ - $\mu $ fading model is well-suited for versatile channels as it adapts to different fading behaviors in a broad-range propagation for non-line-of-sight (NLOS) circumstances. This paper evaluates the performance of heterogeneous wireless networks using $\eta $ - $\mu $ fading channel under mobility conditions. We incorporated the random waypoint (RWP) model with $\eta $ - $\mu $ distribution to model the dynamic behavior of non-homogeneous fading. The derivation of expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the received signal power for a mobile network in all three-dimensional topologies is extracted. Consequently, the outage probability (OP) and average bit error rate (ABER) are analyzed to quantify the performance of the mobile system. The effect of co-channel interference (CCI) is investigated based on a desired and interfering signal transmitted in mobile networks. The proposed novel-form can characterize the performance of a mobile user, and the derivation is useful for measuring the effect of noise and interference on the signal. Finally, the novel-form applicability analyzes the impact of mobility incorporated in different fading channels such as Nakagami-m, Nakagami-q (Hoyt), Rayleigh, and one-sided Gaussian distributions.

Secrecy Performance Analysis of Air-to-Ground Communication With UAV Jitter and Multiple Random Walking Eavesdroppers

Flexible mobility and random jitter are two unique features of UAV communication platforms. Although advantages of mobility have been extensively explored, the random jitter of UAV platforms, caused by airflow and body vibrations, has been rarely studied. This work aims to answer the two fundamental questions: i) how to analyze the secrecy performance when considering UAV jitter and ii) can this inherent characteristic of UAV be exploited to enhance secrecy? Detailed, we study the modeling and analysis of UAV jitter on the secrecy performance in an air-to-ground (A2G) wiretap system with multiple non-colluding eavesdroppers, where a UAV-mounted transmitter equipped with directional antennas illuminates ground terminals in a finite area. Random waypoint model is applied to characterize the mobility of eavesdroppers. To be specific, by modeling UAV jitter in both horizontal azimuth and vertical elevation, distortion and shift of UAV illumination area are analyzed. Further, beam-illumination probability of a randomly located ground terminal is obtained. Following which, a tractable framework for analyzing the secrecy coverage probability (SCP) and ergodic secrecy capacity (ESC) is developed. Expressions for SCP and ESC are derived with characterizations for the signal-to-noise ratio received at legitimate receiver and eavesdroppers. Finally, extensive simulations are provided to validate the theoretical analysis. This is the first work to find that UAV jitter can be exploited to enhanced secrecy performance of A2G wiretap system with appropriate UAV height and beamwidth.

Analysis and modelling the effects of mobility, Churn rate, node’s life span, intermittent bandwidth and stabilization cost of finger table in structured mobile P2P networks

Today P2P (Peer-to-Peer) networks are gaining popularity for sharing the contents. Due to massive spreading of Internet, these networks are also growing fast. MP2P (Mobile P2P) networks are attracting many users due to increase in the Internet-based mobile applications. These networks suffer from many challenges which are not considered for analysis and modelling adequately. We focus on few challenges like mobility of users, churn rate, intermittent bandwidth, shorter life span of mobile nodes, stabilization of finger table, etc. in this paper. We analytically analyse these challenges and define the effects of different parameters over the performance. Traditional P2P protocols are designed for wired networks and when these are implemented for mobile networks then mobility effect of users adds more challenge for researchers. We select two types of mobility models namely FF (Fluid Flow) and RWP (Random Waypoint) models to model the users’ mobility. The churn rate of the mobile nodes makes network overlay management and content searching more difficult in MP2P networks. We select finger table-based protocols which are widely deployed in the P2P networks. But these protocols can’t perform well in the mobile P2P networks due to mobility of the users. The mobility of the users and churn rate of the mobile nodes create failure in lookup of finger table and induce more cost to update the finger table. We consider these challenges and quantify the failure rate of mobile nodes, life span of mobile nodes, available bandwidth, cost of stabilization of finger table per node, etc. in this proposal. The proposed model is useful for modelling the performance of MP2P networks performance in various wireless environments like Mobile Ad hoc Networks (MANETs), Wireless Mesh Networks (WMNs), Wireless Sensor Networks (WSNs), Vehicular Ad hoc Networks (VANETs), Wireless LAN (WLAN), Wireless MAN (WMAN), etc.

On the Security–Reliability and Secrecy Throughput of Random Mobile User in Internet of Things

Physical-layer security (PLS) in Internet of Things (IoT) has attracted great attentions recently. Although mobility is an intrinsic property of IoT networks, most of the existing works only investigate the secure transmission design for static users. To fill this gap, this article specifically investigates the secrecy throughput maximization problems for the mobile IoT user under two typical mobility models: 1) random waypoint model (RWP) and 2) random direction model (RD). The insights about how the mobility patterns, and security–reliability requirements affect the mobile user’s secrecy throughput are revealed. First, in order to establish the relationship between security and reliability of the mobile user, a general analytic framework is provided to derive the closed-form expressions of transmit secrecy outage probability (TSOP) for the mobile user. Second, two transmission schemes are proposed to maximize the secrecy throughput of the mobile user by ensuring a certain level of transmit probability (TP) and TSOP requirements. The numerical and simulation results verify the validity and effectiveness of the proposed schemes, and indicate that by adopting appropriate mobility pattern, the user’s secrecy throughput can be improved, and the constraint on its moving region can be largely reduced. Those properties are lightweight and feasible to enhance security for many mobile IoT scenarios.

Evaluating the feasibility of random waypoint model for indoor wireless networks

Trace‐driven simulations supported by long‐term and human‐based indoor mobility traces are able to properly validate the effectiveness and efficiency of the algorithms, protocols or applications utilized in indoor wireless networks. Nevertheless, most of the mobility models adopted in the existing works are simplified variations of random waypoint (RWP) model. To evaluate the feasibility of RWP model, we extract the real‐time mobility trace of a one‐month period human‐based raw dataset and quantitatively compare the extracted trace to that of RWP model. The comparison results reveal the inaccuracy of RWP model. We also evaluate the use of the indoor mobility trace while studying different mobility‐aware problems of indoor wireless networks.

The impact of mobility model on handover rate in heterogeneous multi-tier wireless networks

Heterogeneous multi-tier wireless networks deploy many small cells to overcome the scarcity of bandwidth for broadband wireless access. However, increasing the number of cells increases the rate of required handover as a mobile user passes through the boundaries of these cells leads to more signaling overhead. We address the impact of mobile users’ mobility model in the urban areas on the handover rate. We use two real data sets to model the mobility pattern of pedestrians and drivers, considering their different velocity, move length, and pause time distributions. We use Poisson Point Processes to model the spatial distribution of base stations and assume that the number of handovers is equal to the number of times the users’ trajectories cross the cell’s boundaries. We derive the distribution function of the handover rate by using the distribution function of the velocity of users. Simulation results are provided to justify the deployed mobility model and the derived analytical results for the handover rate. We find that while the trend of the handover rate against the density of base stations and bias values at different tiers deploying the derived realistic mobility models and simple random waypoint model is the same, the total number of handovers in the network has different behavior. Interestingly, we found that if the number of users increases beyond a threshold, the handover rate decreases, suggesting that the hand over rate is bounded.

A Hybrid Mobile Node Localization Algorithm Based on Adaptive MCB-PSO Approach in Wireless Sensor Networks

In this paper, a hybrid adaptive MCB-PSO node localization algorithm is proposed for three-dimensional mobile wireless sensor networks (MWSNs), which considers the random mobility of both anchor and unknown nodes. An improved particle swarm optimization (PSO) approach is presented with Monte Carlo localization boxed (MCB) to locate mobile nodes. It solves the particle degeneracy problem that appeared in traditional MCB. In the proposed algorithm, a random waypoint model is incorporated to describe random movements of anchor and unknown nodes based on different time units. An adaptive anchor selection operator is designed to improve the performance of standard PSO for each particle based on time units and generations, to maintain the searching ability in the last few time units and particle generations. The objective function of standard PSO is then reformed to make it obtain a better rate of convergence and more accurate cost value for the global optimum position. Furthermore, the moving scope of each particle is constrained in a specified space to improve the searching efficiency as well as to save calculation time. Experiments are made in MATLAB software, and it is compared with DV-Hop, Centroid, MCL, and MCB. Three evaluation indexes are introduced, namely, normalized average localization error, average localization time, and localization rate. The simulation results show that the proposed algorithm works well in every situation with the highest localization accuracy, least time consumptions, and highest localization rates.

Evaluation of RF Energy Harvesting by Mobile D2D Nodes Within a Stochastic Field of Base Stations

Radio frequency energy harvesting can prolong the battery life and improve energy efficiency of device-to-device (D2D) communication. In this paper, we analyze the performance of a mobile D2D device powered by EH from the transmissions of underlying cellular base stations (BSs), whose locations are modeled as a homogeneous Poisson point process. We model the movements of D2D nodes via a modified random waypoint model. Log-distance path loss and Rayleigh fading are considered, and EH takes place solely within harvesting zones surrounding each BS and each D2D user harvests energy for a fixed number of charging time slots before attempting to transmit. We derive the probability of a D2D device being within an EH region surrounding BSs after multiple movements, and the probability of being within the fully charged state using a Markov-chain approach taking into account temporal effects. Moreover, the statistics of the harvested energy are characterized, and subsequently, the outage probability of a D2D transmission utilizing the harvested energy is derived. We show that the number of movements required to be within a harvesting region increases significantly when the harvesting threshold power increases, and that the number of harvesting time slots should be selected judiciously.

RETRACTED ARTICLE: Congestion control load balancing adaptive routing protocols for random waypoint model in mobile ad-hoc networks

Congestion is the main issue for routing in the mobile system which overall degrading performance in the network due to inadequate accessibility of resources of the wireless network of the nature, node mobility and dynamic topology of the wireless network. Congestion causes packet loss, time and energy wastage by connection failure and by mobile node failure. Congestion could be recognized as a base of deployment, link capacity node and routing routes of the network. The congestion detected on node-link by a source node along with the node of the path, which distributes traffic flow over the alternative node paths by considering routing path availability of the network. This paper has proposed a congestion control load balancing adaptive routing protocol (CCLBARP) algorithms on the direction to reduce delay, system routing overhead, congestion and enhances the life of network in MANET. The proposed congestion control technique is compared with original existing routing protocols such as DYMO and DSR of MANET in terms of throughput, end-to-end delay, packet drops average jitter, packet delivery ratio and normalized routing overhead of the network and this CCLBARP get outperformed the DSR and DYMO.