Simulating Real-Time Aspects of Wireless Sensor Networks

Wireless Sensor Networks (WSNs) technology has been mainly used in the applications with low-frequency sampling and little computational complexity. Recently, new classes of WSN-based applications with different characteristics are being considered, including process control, industrial automation and visual surveillance. Such new applications usually involve relatively heavy computations and also present real-time requirements as bounded end-to- end delay and guaranteed Quality of Service. It becomes then necessary to employ proper resource management policies, not only for communication resources but also jointly for computing resources, in the design and development of such WSN-based applications. In this context, simulation can play a critical role, together with analytical models, for validating a system design against the parameters of Quality of Service demanded for. In this paper, we present RTNS, a publicly available free simulation tool which includes Operating System aspects in wireless distributed applications. RTNS extends the well-known NS-2 simulator with models of the CPU, the Real-Time Operating System and the application tasks, to take into account delays due to the computation in addition to the communication. We demonstrate the benefits of RTNS by presenting our simulation study for a complex WSN-based multi-view vision system for real-time event detection

EETP-MAC: energy efficient traffic prioritization for medium access control in wireless body area networks

[EN] Wireless body area network (WBAN) has witnessed significant attentions in the healthcare domain using biomedical sensor-based monitoring of heterogeneous nature of vital signs of a patient's body. The design of frequency band, MAC superframe structure, and slots allocation to the heterogeneous nature of the patient's packets have become the challenging problems in WBAN due to the diverse QoS requirements. In this context, this paper proposes an Energy Efficient Traffic Prioritization for Medium Access Control (EETP-MAC) protocol, which provides sufficient slots with higher bandwidth and guard bands to avoid channels interference causing longer delay. Specifically, the design of EETP-MAC is broadly divided in to four folds. Firstly, patient data traffic prioritization is presented with broad categorization including Non-Constrained Data (NCD), Delay-Constrained Data (DCD), Reliability-Constrained Data (RCD) and Critical Data (CD). Secondly, a modified superframe structure design is proposed for effectively handling the traffic prioritization. Thirdly, threshold based slot allocation technique is developed to reduce contention by effectively quantifying criticality on patient data. Forth, an energy efficient frame design is presented focusing on beacon interval, superframe duration, and packet size and inactive period. Simulations are performed to comparatively evaluate the performance of the proposed EETP-MAC with the state-of-the-art MAC protocols. The comparative evaluation attests the benefit of EETP-MAC in terms of efficient slot allocation resulting in lower delay and energy consumption.The research is supported by Ministry of Higher Education Malaysia (MOHE) and conducted in collaboration with Research Management Center (RMC) at University Teknologi Malaysia (UTM) under VOT NUMBER: R.J130000.7828.4F859Ullah, F.; Abdullah, AH.; Kaiwartya, O.; Lloret, J.; Arshad, MM. (2020). EETP-MAC: energy efficient traffic prioritization for medium access control in wireless body area networks. Telecommunication Systems. 75(2):181-203. https://doi.org/10.1007/s11235-017-0349-518120375

IEEE 802.15.4 MAC Protocol Study and Improvement

IEEE 802.15.4 is a standard used for low rate personal area networks (PANs). It offers device level connectivity in applications with limited ower and relaxed throughput requirements. Devices with IEEE 802.15.4 technology can be used in many potential applications, such as home networking, industry/environments monitoring, healthcare equipments, etc, due to its extremely low power features. Although the superframe beacons play the key role in synchronizing channel access in IEEE 802.15.4, they are sources for energy inefficiency. This research focuses on exploring how to optimize the beacons, and designing novel schemes to distribute the information that are supposed to be delivered to a subset of PAN devices. In this work, an acknowledgement based scheme is proposed to reduce the energy consumption in the distribution of guaranteed time slot (GTS) descriptors. Based on the observation that the superframe beacon frame has global impact on all PAN devices, an energy-efficient channel reservation scheme is presented to deliver the information (GTS descriptors and pending addresses). In addition, the problem of channel underutilization is studied in the contention free period. To address the problem, a new GTS allocation scheme is proposed to improve the bandwidth utilization

A Multi-Hop 6LoWPAN Wireless Sensor Network for Waste Management Optimization

In the first part of this Thesis several Wireless Sensor Network technologies, including the ones based on the IEEE 802.15.4 Protocol Standard like ZigBee, 6LoWPAN and Ultra Wide Band, as well as other technologies based on other protocol standards like Z-Wave, Bluetooth and Dash7, are analyzed with respect to relevance and suitability with the Waste Management Outsmart European FP7 Project. A particular attention is given to the parameters which characterize a Large Scale WSN for Smart Cities, due to the amount of sensors involved and to the practical application requested by the project. Secondly, a prototype of sensor network is proposed: an Operative System named Contiki is chosen for its portability on different hardware platforms, its Open Source license, for the use of the 6LoW-PAN protocol and for the implementation of the new RPL routing protocol. The Operative System is described in detail, with a special focus on the uIPv6 TCP/IP stack and RPL implementation. With regard to this innovative routing proto col designed specifically for Low Power Lossy Networks, chapter 4 describes in detail how the network topology is organized as a Directed Acyclic Graph, what is an RPL Instance and how downward and upward routes are constructed and maintained. With the use of several AVR Atmel modules mounting the Contiki OS a real WSN is created and, with an Ultrasonic Sensor, the filling level of a waste basket prototype is periodically detected and transmitted through a multi-hop wireless network to a sink nodeope

Enabling Mobile Service Continuity across Orchestrated Edge Networks

Edge networking has become an important technology for providing low-latency services to end users. However, deploying an edge network does not guarantee continuous service for mobile users. Mobility can cause frequent interruptions and network delays as users leave the initial serving edge. In this paper, we propose a solution to provide transparent service continuity for mobile users in large-scale WiFi networks. The contribution of this work has three parts. First, we propose ARNAB architecture to achieve mobile service continuity. The term ARNAB means rabbit in Arabic, which represents an Architecture for Transparent Service Continuity via Double-tier Migration. The first tier migrates user connectivity, while the second tier migrates user containerized applications. ARNAB provides mobile services just like rabbits hop through the WiFi infrastructure. Second, we identify the root-causes for prolonged container migration downtime. Finally, we enhance the container migration scheme by improving system response time. Our experimental results show that the downtime of ARNAB container migration solution is 50% shorter than that of the state-of-the-art migration.This work has been partially funded by the H2020 Europe/Taiwan joint action 5G-DIVE (Grant #859881) and also partially funded by the Ministry of Science and Technology, under the Grant Number MOST 108-2634-F-009-006 - through Pervasive Artificial Intelligence Research (PAIR) Labs, Taiwan

The role of cross-layered designs in wireless body area network

With recent advancement, Wireless Body Area Network (WBAN) plays an important role to detect various diseases of a patient in advance and informs the medical team about the life threatening situation. WBAN comprises of small intelligent Biomedical sensors which are implanted inside patient body and attached on the surface of a patient to monitor different vital signs, namely; respiratory rate, ECG, EMG, temperature, blood pressure, glucose. The routing layer of WBAN has the same challenging problems as similarly faced in WSN but the unique challenge is the temperature-rise during monitoring of vital signs and data transmission. IEEE 802.15.6 MAC Superframe of WBAN is different from IEEE 802.15.4 MAC of WSN and provides channels to emergency and non-emergency data for transmission. As similarly seen in WSN, PHY layer of IEEE 802.15.4 and IEEE 802.15.6 provide various modulation techniques for data transmission. The purpose of this study is to familiar with routing layer, MAC layer and PHY layer in the cross-layer design of WBA

Performance Analysis of Drive-thru Internet Access

Drive-thru Internet is considered to be an important solution to provide Internet access for vehicles. By deploying cost-effective and high bandwidth roadside WiFi networks, a vehicle can upload/download considerable data when drive through the coverage area, whereby a myriad of automotive applications can be employed, such as intelligent transportation system, infotainment applications like video/audio streaming, webpage browsing, etc. However, the high mobility of vehicles leads to the intermittent connection between a vehicle and roadside Access Points (APs), which would cause the Internet access delay and throughput degradation. In this thesis, we propose comprehensive modeling and analysis for the drive-thru Internet access performance considering the overhead of the access procedure, which includes the steps of network detection, user authentication and network parameters assignment. We also consider the situation that a vehicle drives through multiple roadside APs' coverage areas and evaluate the performance of traffic offloading from cellular networks to roadside WiFi networks. In specific, firstly, we develop an analytical model to study the dependency of the drive-thru Internet access delay with different factors, i.e., the wireless channel conditions, the number of co-associated WiFi clients, and the employed authentication mechanism, such as the WiFi Protected Access II (WPA2)-Pre-Shared Key (PSK) and the WPA2-802.1X modes. The access procedure is modeled as a discrete Markov chain to calculate the time to exchange all management frames and to evaluate the Internet access delay. The accuracy of the analytical model is studied via computer simulations, as well as experimental testing using Commercial Off-The-Shelf (COTS) WiFi products, together with a channel emulator that emulates the wireless channel conditions in a vehicular environment. Simulation and experiment results validate the accuracy of the proposed analytical model which provides useful guidelines for future selection/development of suitable WiFi network access schemes in a vehicular environment. Secondly, we take a further step to analyze the throughput performance of the drive-thru Internet access. The mobility of the vehicle is modeled as the transition of a series of zones in the coverage area, which is defined based on the relationship between the WiFi link rate and the distance of the AP and the vehicle. A three dimensional (3D) Markov model is proposed to combine the zone transition process and the transmission of the management frames and calculate the average throughput under conditions of different numbers of co-associated WiFi clients, channel qualities and different access protocols. Thirdly, we consider that when the vehicle drives through multiple roadside WiFi networks, and employ the Vehicle-to-Vehicle (V2V) assisted WiFi offloading mechanism, where nearby vehicles that associated to different APs can use their idle WiFi resource to offload part of peer's data traffic. The offloading performance is calculated by modeling the intermittent WiFi transmission as an M/G/1/K queueing process, and the performance gain of the V2V assistance is also analyzed. In summary, the research works in this thesis should provide guidelines for future research and development of drive-thru Internet