Putting contacts into context

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.

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.

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.

Routing protocol based on social characteristics for opportunistic networks

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.

Significant research has been conducted for maintaining a high standard of communication and good coverage in wireless sensor networks (WSNs), but extra power consumption and mobility issues are not yet fully resolved. This paper introduces a memory-less location mobility-aware Lattice Mobility Model (LMM) for WSNs. LMM is capable of concurrently determining the node and sink mobility. LMM has a lower pause time, fewer control packets, and less node dependency (e.g., the energy consumed by each node in each cycle that is independent of the data traffic). LMM accurately determines a node’s moving location, the distance from its previous location to its current location, and the distance from its existing location to its destination. Many existing mobility models only provide a model how nodes move (e.g., to mimic pedestrian behavior), but do not actually control the next position based on properties of the underlying network topology. To determine the strength of LMM, OMNet++ was used to generate the realistic scenario to safeguard the affected area. The operation in affected area comprises searching for, detecting, and saving survivors. Currently, this process involves a time-consuming, manual search of the disaster area. This contribution aims to identify an energy efficient mobility model for a walking pattern in this particular scenario. LMM outperforms other mobility models, including the geographic-based circular mobility model (CMM), the random waypoint mobility model (RWMM) and the wind mobility model (WMM), The simulation results also demonstrate that the LMM requires the least time to change the location, has a lower drop rate, and has more residual energy savings than do the WMM, RWMM, and CMM.

Wireless network of wearable biomedical sensors by human body shows great potential to enhance the biometrics performance significantly. Meanwhile, it poses prominent characteristics and challenges to physicians and engineers for its particular medical application as compared to other application of wireless sensor networks (WSN). Mobility pattern plays an important role in designing the wireless body sensor networks (WBSN) and will also affect the accuracy of modeling WBSN in health care application. Much of the mobility scenarios generated in current work of wireless body sensor networks has used fairly simple models to generate the mobile topological graph, which bear little resemblance to the actual mobility patterns. This paper is the first attempt to investigate the mobility model in WBSN based on the existing mobility models in wireless data networks and ad hoc networks. We first briefly review the existing mobility models in related research areas such as wireless ad hoc network and cellular networks. Further on, we propose a dedicated and more realistic mobility model named BAMM (Body Area Mobility Model) for wireless body sensor networks by concentrating on the unique characteristics of WBSN and finally study the effects of mobility on the performance of WBSN by simulation experiments.

移动模型是Ad Hoc 网络区别于其他形式网络的重要标志,对其产生的动态网络特性(简称动态特性)进行评估,是研究Ad Hoc 网络的协议仿真和网络相关技术(如拓扑控制和网络性能测量等)的基础性问题.在已有研究的基础上,改进了网络的模型化描述,克服了以往模型无法很好地描述相关联的时空动态特性的缺陷,并在此基础上,提出了移动模型通用的可量化时空动态特性评估方法.通过构建节点空间位置分布,建立网络拓扑时空动态特性的分析模型,深入研究了几种移动模型的动态性.提出一种圆周曲线移动模型,弥补了以往移动模型难以描述现实的曲线移动场景.仿真实验结果表明,该方法能够有效地对现有移动模型的动态性进行评估.实验结果表明,圆周曲线移动模型与以往移动模型相比,具有良好的时空动态特性.;Mobility model is a crucial feature to differentiate ad hoc networks from other networks. The evaluation of dynamic network properties caused by mobility model is the basic problem for research on protocol simulation and related technologies, such as topology control and network performance measurement, in ad hoc networks. In this paper, a model-based description of ad hoc networks is improved to avoid the drawbacks in describing the corresponding space-time dynamic properties. Then a universal evaluation method with measureable space-time dynamic properties is presented. The dynamic properties of several mobility models are studied by constructing the space distribution of the nodes and designing the models for analyzing the topological space-time dynamic properties. Furthermore, a novel mobility model based on circular curve movement is proposed to improve the flexibility and the capability to describe realistic scenarios with curve movement. Simulation with NS2 shows the presented method can effectively evaluate the characteristics of the existing mobility models. The numerical results also show that the proposed mobility model has good dynamic properties in comparison with the existing mobility models.

In recent years, several investigations have been made on "challenged network" [also known as, delay tolerant network (DTN)] architectures highlighting their advantages and disadvantages. In spite of its inherent shortcomings of unreliability and delay, smart-phone based opportunistic network is gaining immense popularity in the research community due to its applicability in different adverse and extreme communication scenarios where traditional communication infrastructure is either unavailable or incapacitated for a long time. Considerable research has been conducted till date to design efficient network architecture for emergency data dissemination in intermittently connected/challenged networks. Different architectures (ranging from flat to multi-tier) are proposed for implementing opportunistic DTN keeping in view of specific application requirements. However, very few of these proposed architectures have been examined from the perspective of a post disaster communication. Moreover, most DTN architectures are designed by aiming towards increasing delivery probability and reducing latency and as a whole, maximizing network throughput; with very little emphasis on its energy efficiency. The impact of different mobility patterns on existing DTN routing algorithms with respect to data dissemination and energy consumption has also not been studied so far. Our objective, in this paper, is to investigate the impact of different mobility patterns on existing DTN routing protocols and existing DTN architectures and subsequently, come up with a suitable energy efficient DTN framework combining suitable architecture and routing protocol that may be used to offer different disaster management services during post-disaster relief operation. We have done an extensive simulation on ONE simulator with different categories of well-known existing DTN architectures, mobility models, DTN routing protocols to study the network performance in terms of delivery probability, energy efficiency and overhead ratio. Based on the simulation results, we have tried to figure out a suitable combination of energy efficient architecture, mobility model and routing protocol that fits well in the post disaster communication scenario.

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.

Movement patterns of mobile nodes significantly affect the performance of a Mobile Ad hoc Network (MANET) routing protocol. Thus, it is essential that the mobility traces generated by a mobility model closely match the trace data collected from experiments. In addition, the probability distribution of mobile nodes (over the simulation area) varies with time before it comes to a steady-state. In other words, distribution of mobile nodes in steady-state is independent of their initial position. If traces generated by a mobility model are used before its steady-state is reached, this variability in distribution may lead to misleading results, called initialization bias. Thus, for credible MANET simulations, it is required that a mobility model used (1) is realistic (i.e., its mobility traces closely match the experimental data) and (2) starts in a steady- state (i.e., there is no initialization bias). In this work, we analyze a recently published realistic mobility model, called SLAW. The SLAW mobility model is based on real GPS traces collected from five outdoor sites. Previous work with SLAW is done by discarding the first few hours of simulation time; however, discarding initial data does not guarantee that the model has reached its steady-state. Thus, the main contribution of our work is that we provide methods for sampling from the steady- state distributions of mobile nodes' locations and pause- times. Sampling from the steady-state distributions allows the SLAW mobility model to start in a steady-state and thus, avoids initialization bias related to the mobility model.

Delay-Tolerant Networks (DTN) are intermittent wireless mobile networks designed to handle communications in environments where network connectivity is often disrupted due to node mobility or the absence of fixed infrastructures.These frequent disconnections lead to repeated communication attempts between nodes, thereby increasing energy consumption.DTN is often deployed in isolated and hard-to-reach environments with limited energy sources, imposing significant constraints on the performance and operational lifetime of individual DTN nodes, as well as the DTN network as a whole.Despite the significant efforts invested by researchers to develop energy-efficient algorithms and models, the problem of energy consumption persists, especially with nonrenewable sources.The motivation for this research is based on the major challenges related to powering mobile nodes in DTN networks, notably due to the absence of reliable and constant energy sources.The energy constraints of the nodes, combined with their mobility, raise problems of energy consumption and durability, leading to communication interruptions, delays, data losses, and a decrease in the overall efficiency of the network.To overcome these challenges, the article proposes a long-term energy management strategy by integrating renewable energy sources, notably solar energy, into the architecture of DTN nodes.The contributions include the modeling of an energyautonomous and sustainable solar-powered DTN node, the evaluation of the energy generated and stored by these nodes, and the validation of the effectiveness of this approach through simulations in the ONE simulator, considering realistic mobility scenarios and communication conditions.The results show that solar DTN nodes have significantly higher residual energy than those with limited power sources.Additionally, social mobility models (MBM, SPMBM) consume more energy than individual models (RW, RWP, RD), while the Spray-and-Wait and PROPHET protocols are more energy-efficient compared to Epidemic and MaxProp.These analyses reveal optimal combinations of DTN protocols and mobility models to reduce energy consumption: the Spray-and-Wait protocol aligns well with social mobility models, while PROPHET is more suited to individual mobility models.

In protocol development for wireless systems, the choice of appropriate mobility models describing the movement patterns of devices has long been recognised as a crucial factor for the successful evaluation of protocols. More recently, wireless protocols have also come into the focus of formal approaches to the modelling and verification of concurrent systems. While in these approaches mobility is also given a central role, the actual mobility modelling remains simplistic since arbitrary node movements are allowed. This leads to a huge behavioural overapproximation that might prevent a successful reasoning about protocol properties. In this paper we describe how to extend a process calculus by realistic mobility models in an orthogonal way. The semantics of our calculus incorporates a notion of global time passing that allows us to express a wide range of mobility models currently used in protocol development practice. Using the behavioural equivalence and pre-order of our calculus, we are furthermore able to compare the strength of these models in our approach.

Mobility modelling plays a pivotal role in evaluating the performance of Mobile Ad Hoc Networks (MANETs), as the movement patterns of nodes strongly influence routing efficiency, connectivity, and network stability. Existing mobility models, particularly entity and group-based frameworks, have proven useful in simulating various MANET applications but remain limited in capturing the complex movement behaviour characteristic of Search-and-Rescue (SAR) operations in disaster scenarios. This study proposes a realistic hybrid mobility model that integrates the essential features of both entity and group mobility paradigms to better represent the coordinated yet flexible dynamics of SAR teams. Three sets of simulations were performed using the Network Simulator 2 (NS2). The first and second simulations focused on generating and combining existing entity and group mobility patterns using the BonnMotion tool, resulting in two composite models (Real1 and Real2). The third simulation compared these models using AODV and DSDV routing protocols under varying node mobility levels and traffic conditions. Key performance metrics, including relative mobility, node degree, partition count, link duration, packet delivery ratio (PDR), throughput, and average end-to-end delay, were analysed. Results demonstrate that it is feasible to concatenate existing mobility models into a coherent hybrid framework. Among the developed models, Real2 exhibited superior performance in most test conditions, yielding higher PDR, lower delay, and more stable connectivity than its constituent models. These findings confirm that the performance of MANETs is highly dependent on mobility realism. Consequently, selecting a model that accurately reflects the behavioural characteristics of the target scenario is essential for credible MANET performance evaluation in emergency response contexts.

Mobility pattern plays an important role in designing the wireless body sensor networks (WBSN) and also would affect the performance of WBSN in health care application. This paper is the first attempt to investigate the mobility model in WBSN based on the existing mobility models in wireless data networks and ad hoc networks. We first briefly review the existing mobility models in related research areas such as wireless ad hoc network and cellular networks. Further, we propose a dedicated mobility model for wireless body sensor networks by concentrating on the unique characteristics of WBSN and finally study the effects of mobility on the performance of WBSN by simulation experiments