Salman Ali

Network Challenges for Cyber Physical Systems with Tiny Wireless Devices: A Case Study on Reliable Pipeline Condition Monitoring

The synergy of computational and physical network components leading to the Internet of Things, Data and Services has been made feasible by the use of Cyber Physical Systems (CPSs). CPS engineering promises to impact system condition monitoring for a diverse range of fields from healthcare, manufacturing, and transportation to aerospace and warfare. CPS for environment monitoring applications completely transforms human-to-human, human-to-machine and machine-to-machine interactions with the use of Internet Cloud. A recent trend is to gain assistance from mergers between virtual networking and physical actuation to reliably perform all conventional and complex sensing and communication tasks. Oil and gas pipeline monitoring provides a novel example of the benefits of CPS, providing a reliable remote monitoring platform to leverage environment, strategic and economic benefits. In this paper, we evaluate the applications and technical requirements for seamlessly integrating CPS with sensor network plane from a reliability perspective and review the strategies for communicating information between remote monitoring sites and the widely deployed sensor nodes. Related challenges and issues in network architecture design and relevant protocols are also provided with classification. This is supported by a case study on implementing reliable monitoring of oil and gas pipeline installations. Network parameters like node-discovery, node-mobility, data security, link connectivity, data aggregation, information knowledge discovery and quality of service provisioning have been reviewed.

Routing protocols in Delay Tolerant Networks - a survey

Delay Tolerant Networks (DTN) are a class of networks that lack continuous connectivity between nodes due to limited wireless radio coverage, widely scattered mobile nodes, constrained energy resources, high levels of interference or due to some other similar channel impairment. Examples of such networks are those operating in mobile networks or extreme terrestrial environments, or simply as planned networks in space. The term disruption-tolerant network is also occasionally used in place of DTN. Routing in DTN is challenging because of frequent and long duration periods of non-connectivity. Several routing protocols have been proposed with strategies ranging from flooding to opportunistic approaches. Due to the diversity of available strategies, there is a need to properly classify and evaluate their performance with various angles. In this paper, we study state of the art routing protocols and give a comparison between them with respect to the characteristic features and methodology involved. The pros and cons of each, their performance and open research issues are also discussed.

A utility based resource allocation scheme with delay scheduler for LTE service-class support

LTE standard defines strict requirements for service classes in order to provide end users with exceptional QoS characteristics including fast connectivity and high data rates. However there is no standard scheduling algorithm defined for LTE and the task of protecting end user satisfaction while maintaining service class restrictions is left upon the service provider and currently is an open issue. To address this challenge, in this work we proposed a two-level scheduler with a utility based game theoretic application in the first level that distributes physical resource blocks among classes with different QoS requirements and a delay based air interface scheduling algorithm in the second level that satisfies the strict levels of delay budget requirements defined for LTE classes. A cooperative game is formed between different service class flows by use of a sigmoid utility function that allows for distribution of resources. Lagrangian formulation is used to find the associated Pareto Optimality. The delay based scheduler checks each users packet delay in its respective service class and makes scheduling decisions in the downlink direction utilizing current channel conditions. Simulation results carried out with key performance matrices including throughput, packet loss ratio, system delay and fairness index proved the usefulness and efficacy of the proposed approach as compared to existing Proportional Fair, Exponential Rule and M-LWDF algorithms.

Genetic algorithms in wireless networking: techniques, applications, and issues

In recent times, wireless access technology is becoming increasingly commonplace due to the ease of operation and installation of untethered wireless media. The design of wireless networking is challenging due to the highly dynamic environmental condition that makes parameter optimization a complex task. Due to the dynamic, and often unknown, operating conditions, modern wireless networking standards increasingly rely on machine learning and artificial intelligence algorithms. Genetic algorithms (GAs) provide a well-established framework for implementing artificial intelligence tasks such as classification, learning, and optimization. GAs are well known for their remarkable generality and versatility and have been applied in a wide variety of settings in wireless networks. In this paper, we provide a comprehensive survey of the applications of GAs in wireless networks. We provide both an exposition of common GA models and configuration and provide a broad-ranging survey of GA techniques in wireless networks. We also point out open research issues and define potential future work. While various surveys on GAs exist in the literature, our paper is the first paper, to the best of our knowledge, which focuses on their application in wireless networks.

A capacity and minimum guarantee-based service class-oriented scheduler for LTE networks

Quality-of-service (QoS) requirements have always posed a challenge from scheduling perspective and it becomes more complicated with the emergence of new standards and applications. Classical techniques like maximum throughput, proportional fair, and exponential rule have been used in common network scenarios but these techniques fail to address diverse service requirements for QoS provisioning in long-term evolution (LTE). These QoS requirements in LTE are implemented in the form of delay budgets, scheduling priorities, and packet loss rates. Scheduler design for LTE networks therefore requires handling service class attributes but preciously proposed scheduling methods ignored service class-based design and focused more on single network prospect. To address service class requirements in LTE, we propose a modified radio resource management-based scheduler with minimum guarantee in the downlink following network capacity and service class attributes defined in LTE standard. The scheduler takes advantage of best available channel conditions while maintaining data rates corresponding to minimum resources guaranteed for all major classes including the best effort class. A method is proposed to determine the scheduling resource capacity of active users in LTE networks with an admission control to limit the number of users according to available resources. In addition to closely matched theoretical and simulated active users that can be accommodated in the system, promising results are provided for system delay, throughput, and user mobility.

Fuzzy-based spectrum handoff and Channel selection for Cognitive Radio Networks

Cognitive Radio Networks have changed the communication paradigm by opportunistically using available spectrum. In such networks, Secondary User vacates the channel when it detects the Primary User. The frequent channel switching degrades the throughput of Cognitive Radio Networks. Current schemes suggest only the selection of Primary Channel if there is not any licensed user available. We propose the fuzzy-based system to estimate gain of candidate channels so that the most advantageous channel can be selected. We also incorporate the Signal-to-Interference-plus-Noise Ratio with Primary User Interference to take handoff decision. We claim that Quality-aware channel selection along with primary user susceptibility is important to improve the throughput of Cognitive Radio Networks. Particularly, in multi-radio, multi-channel cognitive radio networks, the throughput can be increased by not only parallel transmissions but also by selecting the channels with higher channel gain.

Performance Analysis on Packet Delivery Ratio and End-to-End Delay of Different Network Topologies in Wireless Sensor Networks (WSNs)

Wireless sensor networks (WSNs) are receiving more popularity in mission critical and delay sensitive industrial applications because they offer low latency and reliable message transmission. In applications like gas leakage detection, monitoring of pressure and industrial process control etc. reliable communication between sink and the sensing nodes is very important. In wireless sensor networks sensing nodes are placed very densely in different environments and mostly with no defined network topology. In industrial setup, the placement of the sensing nodes plays a very important role, most importantly it increases overall system throughput by efficiently transmitting the calibrated readings and providing maximum security to the industrial devices. In this paper we aim to investigate, how different topological settings effects packet delivery ratio (PDR) and End-to-End delay in wireless sensor networks? This paper also focuses on the performance study of three different network topological settings for mission critical applications. We evaluated the performance of wireless sensor network (WSN) by placing the sensor nodes in three different topological designs namely Linear, Tier one and Split Tier one.

Reliable monitoring of oil and gas pipelines using wireless sensor network (WSN) — REMONG

Development in the domain of embedded systems and communication technologies have created an industrial need to automate tasks and to render more control. Rapid advancement in data processing technologies, wireless communication, evolution of Micro-Electromechanical Systems, business intelligence, process planning and control has created a room for improvement in all areas of industrial practices related to oil and gas processing. Reliable monitoring whilst reporting to remote control rooms in a timely manner for oil and gas carrying pipelines creates a bigger challenge due to its lengthy span. In this paper, we investigate and propose an oil and gas pipeline monitoring solution based on wireless sensor networks with reliability focus on leakage sensing and wireless data communication. The system is developed indigenously and provides capability of reporting pipeline health related statistics stretched over large geographical areas.

A Delay-Scheduler Coupled Game Theoretic Resource Allocation Scheme for LTE Networks

LTE standard defines classes with granular requirements in order to provide QoS with fast connectivity and high data rates. The basic Release-8 of LTE and the subsequent modifications do not specify any scheduling algorithm making the task of improving user satisfaction more difficult. In our work, we proposed a two-level scheduler with game theoretic application that distributes resources among classes with fairness and then implements a delay based scheduler to satisfy the strict levels of delay budget requirements of LTE classes. A coalition is formed between different class flows by use of bargaining cooperative game that allows for distribution of physical resource blocks in a fair manner via Shapely function. The delay based scheduler checks and compares users packet delay in a service class to make scheduling decisions in the downlink utilizing recent user reported channel conditions. Simulation results carried out with key performance matrices like packet loss ratio, throughput, fairness index and system delay prove the effectiveness of the proposed approach as compared to Exponential Rule, Proportional Fair and M-LWDF algorithms and its usefulness for supporting both real time and non-real time traffic is verified.

Secure end-to-end communication over GSM and PSTN networks

GSM (Global System for Mobiles) is the most widely spread mobile communication system in the world. An important objective in mobile communication systems is secure speech communication. GSM suffers from various security weaknesses. The GSM voice traffic is secure outside the core network but it has no security over the core network. This system can be made thoroughly secure by encrypting the speech which is to be transmitted on the GSM voice channel. In this paper we have demonstrated a real-time prototype of an end-to-end secure communication system developed in MATLAB Simulink. Our technique comprises of encryption of the speech before entering the GSM handset which adds security and confidentiality to our communication. The encryption algorithm is private to the communicating GSM subscribers and even the service providing company will not judge what was said. This is amazing because now the GSM channel will become exclusively concealed and confidential to the two subscribers so that even the company people cannot listen to them.