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Adnan Aijaz

Publications and source records attributed to Adnan Aijaz.

At least 55 records · Page 3Linked to original sources
arXiv2022

Demo: Untethered Haptic Teleoperation for Nuclear Decommissioning using a Low-Power Wireless Control Technology

Haptic teleoperation is typically realized through wired networking technologies (e.g., Ethernet) which guarantee performance of control loops closed over the communication medium, particularly in terms of latency, jitter, and reliability. This demonstration shows the capability of conducting haptic teleoperation over a novel low-power wireless control technology, called GALLOP, in a nuclear decommissioning use-case. It shows the viability of GALLOP for meeting latency, timeliness, and safety requirements of haptic teleoperation. Evaluation conducted as part of the demonstration reveals that GALLOP, which has been implemented over an off-the-shelf Bluetooth 5.0 chipset, can be a replacement for conventional wired TCP/IP connection, and outperforms WiFi-based wireless solution in same use-case.

cs.NI↗
arXiv2021

Recursive Periodicity Shifting for Semi-Persistent Scheduling of Time-Sensitive Communication in 5G

Various legacy and emerging industrial control applications create the requirement of periodic and time-sensitive communication (TSC) for 5G/6G networks. State-of-the-art semi-persistent scheduling (SPS) techniques fall short of meeting the requirements of this type of critical traffic due to periodicity misalignment between assignments and arriving packets that lead to significant waiting delays. To tackle this challenge, we develop a novel recursive periodicity shifting (RPS)-SPS scheme that provides an optimal scheduling policy by recursively aligning the period of assignments until the timing mismatch is minimized. RPS can be realized in 5G wireless networks with minimal modifications to the scheduling framework. Performance evaluation shows the effectiveness of the proposed scheme in terms of minimizing misalignment delay with arbitrary traffic periodicity.

cs.NI↗
arXiv2021

Infrastructure-less Wireless Connectivity for Mobile Robotic Systems in Logistics: Why Bluetooth Mesh Networking is Important?

Mobile robots have disrupted the material handling industry which is witnessing radical changes. The requirement for enhanced automation across various industry segments often entails mobile robotic systems operating in logistics facilities with little/no infrastructure. In such environments, out-of-box low-cost robotic solutions are desirable. Wireless connectivity plays a crucial role in successful operation of such mobile robotic systems. A wireless mesh network of mobile robots is an attractive solution; however, a number of system-level challenges create unique and stringent service requirements. The focus of this paper is the role of Bluetooth mesh technology, which is the latest addition to the Internet-of-Things (IoT) connectivity landscape, in addressing the challenges of infrastructure-less connectivity for mobile robotic systems. It articulates the key system-level design challenges from communication, control, cooperation, coverage, security, and navigation/localization perspectives, and explores different capabilities of Bluetooth mesh technology for such challenges. It also provides performance insights through real-world experimental evaluation of Bluetooth mesh while investigating its differentiating features against competing solutions.

cs.RO↗
arXiv2021

Demystifying the Performance of Bluetooth Mesh: Experimental Evaluation and Optimization

Mesh connectivity is attractive for Internet-of- Things (IoT) applications from various perspectives. The recent Bluetooth mesh specification provides a full-stack mesh networking solution, potentially for thousands of nodes. Although Bluetooth mesh has been adopted for various IoT applications, its performance aspects are not extensively investigated in literature. This paper provides an experimental evaluation of Bluetooth mesh (using Nordic nRF52840 devices) with an emphasis on those aspects which are not well-investigated in literature. Such aspects include evaluation of unicast and group modes, performance under different traffic patterns, impact of message segmentation, and most importantly, latency performance for perfect reliability. The paper also investigates performance enhancement of Bluetooth mesh based on different techniques including parametric adjustments, extended advertisements (introduced in Bluetooth 5.0), power control, and customized relaying. Results provide insights into system-level performance of Bluetooth mesh while clarifying various important issues identified in recent studies.

cs.NI↗
arXiv2021

Evaluating the Performance of Over-the-Air Time Synchronization for 5G and TSN Integration

The IEEE 802.1 time-sensitive networking (TSN) standards aim at improving the real-time capabilities of standard Ethernet. TSN is widely recognized as the long-term replacement of proprietary technologies for industrial control systems. However, wired connectivity alone is not sufficient to meet the requirements of future industrial systems. The fifth-generation (5G) mobile/cellular technology has been designed with native support for ultra-reliable low-latency communication (uRLLC). 5G is promising to meet the stringent requirements of industrial systems in the wireless domain. Converged operation of 5G and TSN systems is crucial for achieving end-to-end deterministic connectivity in industrial networks. Accurate time synchronization is key to integrated operation of 5G and TSN systems. To this end, this paper evaluates the performance of over-the-air time synchronization mechanism which has been proposed in 3GPP Release 16. We analyze the accuracy of time synchronization through the boundary clock approach in the presence of clock drift and different air-interface timing errors related to reference time indication. We also investigate frequency and scalability aspects of over-the-air time synchronization. Our performance evaluation reveals the conditions under which 1 \(μ\)s or below requirement for TSN time synchronization can be achieved.

cs.NI↗
arXiv2021

Open and Programmable 5G Network-in-a-Box: Technology Demonstration and Evaluation Results

The fifth-generation (5G) mobile/cellular technology is a game changer for industrial systems. Private 5G deployments are promising to address the challenges faced by industrial networks. Programmability and open-source are two key aspects which bring unprecedented flexibility and customizability to private 5G networks. Recent regulatory initiatives are removing barriers for industrial stakeholders to deploy their own local 5G networks with dedicated equipment. To this end, this demonstration showcases an open and programmable 5G network-in-a-box solution for private deployments. The network-in-a-box provides an integrated solution, based on open-source software stack and general-purpose hardware, for operation in 5G non-standalone (NSA) as well as 4G long-term evolution (LTE) modes. The demonstration also shows the capability of operation in different sub-6 GHz frequency bands, some of which are specifically available for private networks. Performance results, in terms of end-to-end latency and data rates, with a commercial off-the-shelf (COTS) 5G device are shown as well.

cs.NI↗
arXiv2021

Closing the Loop: A High-Performance Connectivity Solution for Realizing Wireless Closed-Loop Control in Industrial IoT Applications

High-performance real-time wireless connectivity is at the heart of the Industrial Internet-of-Things (IIoT). Realizing wireless closed-loop control is crucial for various mission-critical IIoT systems. Existing wireless technologies fall short of meeting the stringent performance requirements of closed-loop control. This paper presents a novel wireless solution, called \textsf{GALLOP}, for realizing closed-loop control over multi-hop or single-hop networks. \textsf{GALLOP} adopts a pragmatic design approach for addressing the challenges of wireless closed-loop control. Key design aspects of \textsf{GALLOP} include control-aware bi-directional scheduling for cyclic exchange, robust retransmission techniques based on cooperative multi-user diversity and low-overhead signaling for scalable operation. \textsf{GALLOP} has been specifically designed for control loops that are closed over the whole network with dynamics on the order of few milliseconds. Performance evaluation based on extensive system-level simulations and hardware implementation on a Bluetooth 5 testbed demonstrates that \textsf{GALLOP} provides high-performance connectivity with very low and deterministic latency, very high reliability and high scalability, to meet the stringent requirements of wireless closed-loop control for versatile IIoT applications.

cs.NI↗
arXiv2021

Energy-Efficient MAC for Cellular IoT: State-of-the-Art, Challenges, and Standardization

In the modern world, the connectivity-as-we-go model is gaining popularity. Internet-of-Things (IoT) envisions a future in which human beings communicate with each other and with devices that have identities and virtual personalities, as well as sensing, processing, and networking capabilities, which will allow the developing of smart environments that operate with little or no human intervention. In such IoT environments, that will have battery-operated sensors and devices, energy efficiency becomes a fundamental concern. Thus, energy-efficient (EE) connectivity is gaining significant attention from the industrial and academic communities. This work aims to provide a comprehensive state-of-the-art survey on the energy efficiency of medium access control (MAC) protocols for cellular IoT. we provide a detailed discussion on the sources of energy dissipation at the MAC layer and then propose solutions. In addition to reviewing the proposed MAC designs, we also provide insights and suggestions that can guide practitioners and researchers in designing EE MAC protocols that extend the battery life of IoT devices. Finally, we identify a range of challenging open problems that should be solved for providing EE MAC services for IoT devices, along with corresponding opportunities and future research ideas to address these challenges.

cs.NI↗
arXiv2021

System Performance Insights into Design of RIS-assisted Smart Radio Environments for 6G

In state-of-the-art wireless networks, the radio environment is beyond the control of the operators which leads to several issues. For example, signal attenuation limits radio connectivity, multi-path propagation results in fading phenomena and reflections/refractions from large objects are the main sources of uncontrollable interference. To overcome these issues, a new technology referred to as reconfigurable intelligent surfaces (RISs) has been brought to light. RISs, whose interactions with the electromagnetic waves are reconfigurable, are at the heart of the smart radio environments for beyond 5G (or 6G) wireless systems. Research on design of smart radio environments is still in infancy. To this end, this paper provides performance insights for design of RIS-assisted smart radio environments. By extending a recent system-level simulator and through extensive simulations, it investigates the impact of positioning/placement of RISs, the number of reflecting elements and the tilt/rotation of RISs in both single and multi-RIS environments. Results reveal that these aspects are crucial to achieving capacity and reliability enhancements in smart radio environments.

cs.NI↗
arXiv2020

6TiSCH++ with Bluetooth 5 and Concurrent Transmissions

Targeting dependable communications for industrial Internet of Things applications, IETF 6TiSCH provides mechanisms for efficient scheduling, routing, and forwarding of IPv6 traffic across low-power mesh networks. Yet, despite an overwhelming body of literature covering both centralized and distributed scheduling schemes for 6TiSCH, an effective control solution for large-scale multi-hop mesh networks remains an open challenge. This paper addresses this with a novel approach that eliminates much of the routing and link-layer overhead incurred by centralized schedulers, and provides a robust mechanism for data dissemination synchronization within 6TiSCH. Specifically, we leverage the physical layer (PHY) switching capabilities of modern low-power wireless platforms to build on recent work demonstrating the viability of Concurrent Transmission (CT)-based flooding protocols across the Bluetooth 5 (BT 5) PHYs. By switching the PHY and MAC layer at runtime, we inject a BT 5-based CT flood within a standard IEEE 802.15.4 TSCH slotframe, thereby providing a reliable, low-latency scheme for 6TiSCH control messaging. We present an analytical model and experimental evaluation showing how our solution not only exploits the BT 5 high data-rate PHY layers for rapid data dissemination, but can also provide reliable 6TiSCH association and synchronization even under external radio interference. We further discuss how the proposed technique can be used to address other open challenges within the standard.

cs.NI↗
arXiv2020

Demo: Slicing-Enabled Private 4G/5G Network for Industrial Wireless Applications

Private deployments of 4G and 5G networks in industrial environments are beneficial from various aspects. Private 4G/5G networks typically face the challenge of supporting heterogeneous industrial applications. This technology demonstration highlights the importance of network slicing in private 4G/5G networks. It shows that network slicing is crucial for performance guarantees in multi-service co-existence scenarios. With network slicing, our private 4G/5G network successfully supports closed-loop control, event-driven control and video streaming applications.

cs.NI↗
arXiv2020

Recent Results on Proportional Fair Scheduling for mmWave-based Industrial Wireless Networks

Millimeter wave (mmWave) communication has recently attracted significant attention from both industrial and academic communities. The large bandwidth availability as well as low interference nature of mmWave spectrum is particularly attractive for industrial communication. However, inherent challenges such as coverage and blockage of mmWave communication cause highly fluctuated channel quality. This paper explores wireless medium access control (MAC) schedulers for mmWave-based industrial wireless applications. Our objective is to design a high-performance and enhanced fairness MAC scheduling algorithm that responds rapidly to channel variations. The key contribution of our work is a method to modify the standard proportional fair (SPF) scheduler. It introduces more flexibility and dynamic properties. Compared to the SPF, our enhanced proportional fair (EPF) scheduler not only improves the priority for users in poor channel conditions but also accelerates the reaction time in fluctuated channel conditions. By providing higher fairness for all users and enhancing system robustness, it particularly adapts to the scatter-rich industrial mmWave communication environment. Through extensive performance evaluation based on the widely accepted network simulator (ns-3), we show that the new scheduler achieves better performance in terms of delivering ultra-low latency and reliable services over mmWave-based industrial communication.

cs.NI↗
arXiv2020

Private 5G: The Future of Industrial Wireless

High-performance wireless communication is crucial in digital transformation of industrial systems which is driven by Industry 4.0 and the Industrial Internet initiatives. Among the candidate industrial wireless technologies, 5G (cellular/mobile) holds significant potential. Operation of private (non-public) 5G networks in industrial environments is promising to fully unleash this potential. This article provides a technical overview of private 5G networks. It introduces the concept and functional architecture of private 5G while highlighting the key benefits and industrial use-cases. It explores spectrum opportunities for private 5G networks. It also discusses design aspects of private 5G along with the key challenges. Finally, it explores the emerging standardization and open innovation ecosystem for private 5G.

cs.NI↗
arXiv2020

High-Performance Industrial Wireless: Achieving Reliable and Deterministic Connectivity over IEEE 802.11 WLANs

Communication for control-centric industrial applications is characterized by the requirements of very high reliability, very low and deterministic latency and high scalability. Typically, IEEE 802.11-based wireless local area networks (WLANs), also known as Wi-Fi networks, are deemed ineligible for industrial control applications owing to insufficient reliability and non-deterministic latency. This paper proposes a novel solution for providing reliable and deterministic communication, through Wi-Fi, in industrial environments. The proposed solution, termed as \textsf{HAR\(^\text{2}\)D-Fi} (\underline{H}ybrid channel \underline{A}ccess with \underline{R}edundancy for \underline{R}eliable and \underline{D}eterministic Wi-\underline{Fi}), adopts hybrid channel access mechanisms for achieving deterministic communication. It also provides temporal redundancy for enhanced reliability. \textsf{HAR\(^\text{2}\)D-Fi} implements different medium access control (MAC) designs that build on the standard physical (PHY) layer. Such designs can be classified into two categories: (a) MAC designs with pre-defined (physical) time-slotted schedule, and (b) MAC designs with virtual time-slotted schedule. Performance evaluation, based on analysis and system-level simulations, demonstrates the viability of \textsf{HAR\(^\text{2}\)D-Fi} for control-centric industrial applications.

cs.NI↗
arXiv2019

Toward Real-Time Wireless Control of Mobile Platforms for Future Industrial Systems

The use of mobile platforms (MPs) is particularly attractive for various industrial applications. This demonstration highlights the importance of remote control of MPs and shows its viability over a high-performance wireless solution designed for closed-loop control. Further, it shows the viability of formation control of a network of MPs through a leader-follower approach underpinned by high-performance wireless.

cs.NI↗
arXiv2019

Packet Duplication in Dual Connectivity Enabled 5G Wireless Networks: Overview and Challenges

Enabling ultra-reliable low latency communications (uRLLC) over 5G wireless networks creates challenging design requirements, particularly on the air-interface. The stringent latency and reliability targets require enhancements at different layers of the protocol stack. On the other hand, the parallel redundancy protocol (PRP), wherein each data packet is duplicated and transmitted concurrently over two independent networks, provides a simple solution for improving reliability and reducing latency in wireless networks. PRP can be realized in cellular networks through the dual connectivity (DC) solution. Recently, 3GPP has introduced packet duplication functionality in 5G wireless networks. To this end, this paper provides an overview of the packet duplication functionality in 5G, in light of recent developments within 3GPP, and also highlights the related technical challenges.

cs.NI↗
arXiv2019

Exploiting CSMA/ECA and Adaptive Sensitivity Control for Simultaneous Transmit and Receive in IEEE 802.11 WLANs

Ever since the feasibility of in-band full-duplex (FD) at the Physical (PHY) layer has been established, several studies have emerged investigating protocol aspects of enabling FD operation in various legacy wireless technologies. Recently, the adoption of a simultaneous transmit and receive (STR) mode for next generation wireless local area networks (WLANs) has received significant attention. Enabling STR mode (FD communication mode) in 802.11 WLANs creates bi-directional FD (BFD) and uni-directional FD (UFD) links. STR mode in 802.11 WLANs must be enabled with minimal protocol modifications while accounting for the co-existence and compatibility with legacy nodes and protocols. This paper provides a novel solution, that can leverage carrier sense multiple access with enhanced collision avoidance (CSMA/ECA) and adaptive sensitivity control mechanisms, for enabling STR operation. The key aspects of the proposed solution include co-existence with legacy nodes, identification of eligible nodes for UFD, optimization of secondary BFD and UFD transmissions, and creation of UFD opportunities. Performance evaluation demonstrates that the proposed solution is effective in achieving the gains provided by STR operation.

cs.NI↗