Mobility Models and Behavioural Equivalence for Wireless Networks

The study of mobile ad hoc networks depends on understanding protocols from simulations, before applying on a real world setting. To produce a real-world environment within which an ad hoc network can be formed among a set of nodes, there is a need for the development of a realistic, generic and comprehensive mobility model instead of random-based models. Previously, realistic mobility models such as obstacle mobility and pathway mobility model, etc, has been proposed. In these mobility models, there are movement paths and obstacles that constrain the movements and signals of the nodes. In this paper, we propose a new Obstacle Mobility Model Based On Activity Area. In this model our focus is on the movement pattern of the nodes, first we constructed environment simulation that included predefined pathways and obstacles. Then, we consider several clusters each of which has a given geographic activity area, speed and capacity. The nodes become member of clusters. In our model similar to real world, each node belongs to a particular activity area that its existence probability, in this area, is more than other places. This paper shows that various MANET environments can be modeled based on this work. A sample environment is also simulated and the result is compared with the Obstacle Mobility and Random Waypoint model. The results show that movement pattern and speed of the nodes have a significant influence on the performance of MANET protocols.

SummaryThe advances of localization‐enabled technologies have led to huge volumes of large‐scale human mobility data collected from Call Data Records (CDR), Global Positioning System (GPS) tracking systems, and Location Based Social networks (LBSN). These location data that encompass mobility patterns could generate an important value for building accurate and realistic mobility models and hence important value for fields of application including context‐aware advertising, city‐wide sensing applications, urban planning, and more. In this paper, we investigate the underlying spatio‐temporal and structural properties for human mobility patterns, and propose the Community and Geography Aware Mobility (CGAM) model, which characterizes user mobility knowledge through several properties such as home location distribution, community members' distribution, and radius of gyration. We validate the CGAM synthetic traces against real‐world GPS traces and against the traces generated by the baseline mobility model SMOOTH and assess that CGAM is accurate in predicting the performance of flooding‐based and community‐based routing protocols.

The nature of mobile ad hoc networks (MANETs) makes simulation research provide invaluable support for investigating mobile networking protocols, services and applications. Mobility is one of the main factors in simulation of MANETs, due to the fact that it has a strong impact on the design and performance of the networks. Mobility modeling has been an active field for the past decade, mostly focusing on matching a specific mobility or encounter metric with little focus on matching irregular obstacle constraints in realistic scenarios. Consequently, the existing mobility models (MMs) are almost unrealistic. On the other hand, the lack of systemic evaluation framework for MMs makes the mobility characteristics of MANETs be not properly evaluated. In this paper, a realistic mobility model based on Bezier curves (RMBC) is presented. The model operates in an irregular obstacle environment which restricts node movement and wireless transmission. In the RMBC model, a mobile node can calculate smooth pathways between the obstacles using the Bezier curve characterized by control points. Moreover, the flexible movement manners and the realistic application characteristics determined by RMBC are derived and analyzed, respectively. In order to effectively compare the proposed MM with several classical MMs, an integrated and systemic evaluation framework with a multi-dimensional mobility metric space is achieved. The simulation using NS2 tool is conducted. The results show that the proposed MM performs significantly better than the existing MMs in terms of mobility characteristics of MANETs in realistic scenarios.

Mobile Ad Hoc Network is a collection of mobile nodes forming temporary network. In MANET routing protocols are classified as Proactive, Reactive and Hybrid. The work presented here evaluates performance of three Reactive routing protocols such as AODV, DSR and TORA under six performance metrics such as packet delivery ratio, routing overhead, packet loss, normalized routing load, throughput and end to end delay The nodes follow two realistic mobility models such as Reference Point Group Mobility model (RPGM) and Manhattan Grid (MG) model. This work also presents the statistical analysis of AODV, DSR and TORA in Manhattan Grid (MG) model and Reference Point Group Mobility (RPGM) model in low load with low speed, average load with average speed, high load with high speed and very high load with high speed. Contribution in this work is beneficial in deciding which protocol to choose for better QoS.

The mobility model is one of the most important factors in the performance evaluations of a mobile ad hoc network (MANET). The Manhattan mobility model has been used to model the node's mobility, where the movement pattern of mobile node on streets and roads defined by maps. However, DakNet ad hoc network that uses wireless technology to provide digital connectivity among villages, kiosks and private communication devices and between kiosks and a hub (for non-real time internet access) using low-cost WiFi radio transceivers. One typical mobility behavior is geographical restriction movement. To investigate DakNet scenario an underlying realistic mobility model is desired. In this paper, we propose a novel mobility model “Digital Postal Mobility Model” (DPMM), which closely approximates the mobility patterns in DakNet scenario; it models the movement of nodes at pre-defined path and have a set of destinations and also visit all destination. We demonstrate our proposed mobility model by evaluating various MANET routing protocols, including DSR and DSDV, the performance of DPMM is efficient than existing geographical restricted models and NS simulation results shows that the choice of mobility model has significant impact on network performance.

Realistic mobility models are crucial for the simulation of Delay Tolerant and Opportunistic Networks. The long standing benchmark of reproducing realistic pairwise statistics (e.g., contact and inter-contact time distributions) is today mastered by state-of-the-art models. However, mobility models should also reflect the macroscopic community structure of who meets whom. While some existing models reproduce realistic community structure - reflecting groups of nodes who work or live together - they fail in correctly capturing what happens between such communities: they are often connected by few bridging links between nodes who socialize outside of the context and location of their home communities. In a first step, we analyze the bridging behavior in mobility traces and show how it differs to that of mobility models. By analyzing the context and location of contacts, we then show that it is the social nature of bridges which makes them differ from intra-community links. Based on these insights, we propose a Hypergraph to model time-synchronized meetings of nodes from different communities as a social overlay. Applying this as an extension to two existing mobility models we show that it reproduces correct bridging behavior while keeping other features of the original models intact.

Vehicular Ad Hoc Network (VANET) is a practical solution of intelligent transportation system which combines the interaction between technology and network traffic. To develop VANET communication services, a realistic mobility environment must be primarily generated because it has a significant effect on routing protocol performance. In this paper, a realistic mobility model from Makassar, Indonesia is proposed to test the performance of AODV and OLSR routing protocols in Packet Delivery Ratio (PDR), End To End Delay (E2ED) and Overhead Ratios. The simulation results show that random mobility model produce better PDR with 83% for AODV and 87% for OLSR. Then E2ED showed similar result for both of mobility model. But AODV has the longest delay with 0.54 second on proposed mobility model. It's different with PDR and E2ED, overhead value showed better performance on proposed mobility model ie 0.83 for AODV and 0.67 for OLSR.

Critical and public safety operations require real-time communication from the incident area(s) to the distant operations command center going through the evacuation and medical support areas. Data transmitted throughout such type of network is extremely useful for decisions makers and operations' conducting. Therefore, any delay in communication may cause lives' loss. Above all, the existing infrastructure communication systems (PSTN, WiFi, 4/5 G, etc.) can be damaged and is often not available solution. An alternate option is to deploy autonomous tactical network at unpredictable location and time. However, in this context there are many challenge especially how to effectively rout or disseminate the information. In this paper, we present behavior of varied multi-hops routing protocols evaluated in a disaster-simulated scenario with different communication technologies (i.e. WiFi IEEE 802.11; WSN IEEE 802.15.4; WBAN IEEE 802.15.6). Studied routing strategies are classified: Ad hoc proactive and reactive protocols, geographic-based and gradient-based protocols. To be realistic, we have conducted our simulations by considering a Mall in Doha city in the State of Qatar. Moreover, we have generated a mobility trace to model the rescue teams and crowd movements during the disaster. In conclusion, extensive simulations showed that WiFi IEEE 802.11 is the best wireless technology to consider in an emergency urban with the studied protocols. On the other hand, gradient based routing protocol performed much better especially with WBAN IEEE 802.15.6. Keyword: Tactical Ad-hoc Networks; Public Safety and Emergency; Routing Protocols; IEEE 802.11; IEEE 802.15.4; IEEE 802.15.6; Performance Evaluation I. Introduction Public safety is a worldwide governments' concern. It is a special continuous reactive set of studies, operations and actions in order to predict plan and perform a successful reaction in a disaster case. Coupled with the raise of number and variety of disasters, not only the economies and infrastructures are affected, but significant number of human lives. With regards to the emergency response to these disasters, the role of existing Public Safety Network (PSN) infrastructures (e.g. TETRA, LTE) is extremely vital. However, it is anticipated that, during and after the disasters, existing PSN infrastructures can be flawed, oversaturated or completely damaged. Therefore, there is a growing demand for ubiquitous emergency response system that could be easily and rapidly deployed at unpredictable location and time. Wherefore Wearable Body Area Networks (W-BAN) is a relevant candidate that can play a key role to monitor the physiological status of involved workforces and the affected individuals. Composed by small and low-power devices connected to a coordinator, WBAN communication architecture relies on three levels: On-Body (or intra-Body), Body-to-Body (or inter-Body) and off-Body communication networks. In disaster scenarios, the network connectivity and data is a challenging problem due to the dynamic mobility and harsh environment [1]. It is envisioned that, in case of unavailable or out-of-range network infrastructures, the WBANs coordinators along with WBANs sensors can exploit cooperative and multi-hop body-to-body communications to extend the end-to-end network connectivity. The Opportunistic and Mobility Aware Routing (OMAR) scheme is an on-body routing protocol proposed in one of our earlier works [2]. A realistic mobility model is also a major challenge related to the simulations. To the best knowledge of the authors, no comparable study in disaster context is conducted by considering a realistic disaster mobility pattern. In this paper, we investigate varied classes of multi-hop Body-to-Body routing protocols using a realistic mobility modeling software provided by Bonn University in Germany [3]. The mobility pattern is exploited by the WSNET simulator as a mobility trace of the nodes moving during and after the disaster. Note here that individuals are considered mobile nodes in the scenario. In the conducted simulations, each iteration, one communication technology configuration is selected (i.e. WiFi IEEE 802.11; WSN IEEE 802.15.4; WBAN IEEE 802.15.6), then simulations are ran with the routing protocols (i.e. proactive, reactive, gradient-based and geographical-based). This strategy provides a vision not only on the behavior of the routing protocols in the disaster context, but evaluates the communication technologies in such case also. For proactive, reactive, gradient-based and geographical-based routing protocols, Optimized Link State Routing protocol version 2 (OLSRv2) [4], Ad-hoc On-Demand Distance Vector (AODVv2) [5], Directed Diffusion (DD) [6] and Greedy Perimeter Stateless Routing (GPSR) [7] protocols are selected respectively The remainder of this abstract is organized as follows. In section II, we present briefly the disaster scenario considered. In section III, we explain the results of the simulations. Finally, in Section IV, we conclude and discuss perspectives. II. Landmark disaster scenario we are investigating a disaster scenario (fire triggering) in the “Landmark” shopping mall. The mobility model used is generated by the BonnMotion tool. We assume that the incident is caused by fire into two different locations. Rescuers are immediately called to intervene. We consider that firefighters are divided into 3 groups of vehicles with 26 firefighters in each group. Medical emergency teams that probably could reach the mall just after the incident, are consisting of 6 ambulances with 5 medical staff in each ambulance (30 rescuers in total). Civilians could also help rescuers and they are also considered in the mobility trace generation. Injured individuals are transported from the incident areas to the patients waiting for treatment areas to get first aids. Then, they will be transported to the patients clearing areas where they will be either put under observation or evacuated to hospitals by ambulance or helicopter. A tactical command center conducting the operations is represented by WSNET is an event-driven simulator for wireless networks. WSNET is able to design, configure and simulate a whole communication stack from the Physical to the Application Layer. We benefit from these features to vary the payload with the selected MAC and routing layer in each iteration. These combinations provided a deep review on the possible communication architecture to consider in disaster operations. The following section describes the outcome of these extensive simulations. III. Performance evaluation The main difference between the disaster and any other scenario is the emergency aspect. All flowing data in the network is considered highly important. The probability of packets that did not reach the destination must be zero. For this reason, our evaluation is regarded to the Packet Reception rate (PRR). Likewise, a delayed packet is such like an unreceived packet. That's why we consider the delay as decisive factor. Similarly, the energy consumption is also observed. The following table summarizes the obtained results. In terms of average PRR, WiFi IEEE 802.11 is convincingly better than the two counterparts combined with all the routing protocols. GPSR has a considerable PRR with WBAN IEEE 802.15.6, but the location information of the nodes is considered as known. Regarding the delay, DD is particularly efficient with WiFi and WBAN. To conclude, DD is an efficient routing protocol to consider in case of Indoor operations, while GPSR is most relevant in Outdoor operations where locations can be obtained from GPS. IV. Conclusion Disasters are growing remarkably worldwide. The existing communication infrastructures are not considered a part of the communication recuing system. Consequently, to monitor deployed individuals (rescue teams, injured individuals, etc.) data should be forwarded throughout these individuals (WBANs) to reach a distant command center. In order to evaluate the performance of diverse multi-hop routing protocols, we have conducted extensive simulations on WNSET using a realistic mobility model. The simulations showed that all evaluated routing protocols (i.e.AODVv2, OLSRv2, DD and GPSR) has the best PRR with the WiFi technology. While, DD was found to be the most efficient with the WBAN technology. GPSR also could be considered when the location information is available. Acknowledgment The work was supported by NPRP grant #[6-1508-2-616] from the Qatar National Research Fund which is a member of Qatar Foundation. The statements made herein are solely the responsibility of the authors.

The performance evaluation of ad hoc network components through simulation allows for isolation of parameters, easy access to global quantities and a statistically significant number of repeatable trials. In designing network protocols, it is important to investigate the relationship between global network performance and the underlying locally observed network characteristics. Mobility models are used to define the movement of nodes in the simulation space. A wide variety of mobility models exist, and the choice of mobility model has significant influence over locally observed metrics. Unfortunately, many mobility models exhibit spatial and temporal non-stationarity of important metrics, such that global averages of certain metrics are not representative of local observations. This finding impacts on the development of adaptive ad hoc architectures. This paper explores the spatial stationarity of frequently used mobility models. It focuses on the importance of stationarity in relation to the evaluation of performance studies. The spatial non-stationarity of link statistics, and the impact of this artefact on network performance evaluation is examined for the Toroidal Random Waypoint and Random Direction mobility models. We show that the Toroidal Random Waypoint model exhibits spatial stationarity of link statistics. Furthermore, we demonstrate that network performance studies in spatially stationary environments produce dissimilar results to those produced by non-stationary environments. This shows the importance of spatial stationarity when investigating global network performance and locally observed network characteristics.

Urban pedestrian mobility for mobile wireless network simulation

Evaluating large scale vehicular networks solutions is a great challenge once real experiments are not feasible yet and there are no large scale testbeds available. Thus, the most used evaluation technique is simulation, which requires a realistic mobility model to provide accurate results. However, building large scale realistic vehicular mobility models is a hard task and many important characteristics have been neglected, like the origin-destination (O-D) macroscopic one. In this work it is proposed a trace-based O-D macroscopic model inferred by the adoption of statistical techniques in order to characterize a validated traffic model. This work contributes to the research community by providing a more realistic O-D macroscopic model, which can be considered a complement for many traffic generators available in literature.

With the rapid growth in wireless communication technologies, mobility management research is in great demand. Simulation has become an effective method to study the performance of many mobility issues. A realistic mobility model not only reflects mobile user behavior, but also affects correctness of the simulation results. In a wireless environment, obstacles usually exist within the coverage area. We propose a new detour model by using Delaunay triangulation through the incorporation of obstacles. The proposed mobility model can create detour paths as long as there exist gaps among obstacles. Comparative studies show that our proposed model can construct more detour paths than the Voronoi model.

Within the extent of research activity in the field of vehicular networking, notwithstanding the quantity of simulative studies carried out on protocols performance, the impact of vehicular mobility characterization has been often overlooked. Realistic mobility models are seldom employed, and when used, no comment is usually provided on the different effects that such models have on the results with respect to simpler mobility descriptions. In this paper, we address this issue, and analyze the impact that various levels of details in vehicular mobility modeling have on the simulation of networking protocols.

Connectivity analysis of Vehicular Ad Hoc Networks (VANETs) involves the study of static and dynamic characteristics of the network. Realistic mobility models are essential for both aspects, in order to produce valid configurations of the position of vehicles in one static instant, and to dynamically move such vehicles in an interval of time. Focusing on static connectivity evaluation, we extend the state-of-the-art of the realism of urban mobility models for VANETs, by proposing and implementing an analysis based on a stereoscopic aerial survey over a large European city. Our static connectivity metrics show important differences compared to the model and simulation based results described in the VANET literature.

In order to accurately evaluate new concepts and protocols for mobile communication networks, realistic mobility models are needed. Furthermore, for use cases which have a bidirectional dependency between communication and mobility, changes in communication lead to changes in mobility and vice versa, thus requiring an online coupling between models. Therefore, bidirectional coupling to incorporate realistic mobility patterns is state of the art in the analysis of Vehicular Ad-Hoc Network (VANET) applications.However, the same need exist for use cases where the mobile users are pedestrians rather than vehicles. Therefore, this paper introduces our current, on-going work on connecting OMNeT++ and Vadere, an open source simulation framework for microscopic pedestrian dynamics, to benefit from state of the art pedestrian mobility models in mobile communication use cases. The presented coupling is based on the existing Traffic Control Interface (TraCI) protocol used in the Veins (Vehicles in Network Simulation) framework to connect OMNeT++ with SUMO.