arXiv subjects

Adnan Aijaz

Publications and source records attributed to Adnan Aijaz.

63 records · Page 4Linked to original sources

arXiv2019

On Performance Evaluation of Random Access Enhancements for 5G uRLLC

One of the key challenges in realizing ultra-reliable low-latency communications (uRLLC) for factories-of-the-future (FoF) applications is to enhance the cellular random access channel (RACH) procedure. The state-of-the-art LTE RACH procedure does not fulfil the latency requirements for envisioned FoF applications. Moreover, it becomes challenging due to congestion and overloading from massive machine type communication (mMTC) devices leading to collisions especially in a densely populated factory scenarios. The main objective of this paper is to conduct a comprehensive performance evaluation of different random access (RA) enhancements for uRLLC over 5G wireless networks. Our performance evaluation is based on a realistic system-level simulator. The core enhancements considered in this work include early data transmission (EDT), reserved preambles and the use of flexible physical (PHY) layer numerology. We also propose three new RA enhancements for uRLLC. Performance evaluation demonstrates that the proposed RA enhancements can fulfil the 3GPP control plane target of less than 10 ms latency with 99.99% reliability in factory environments.

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arXiv2018

Toward a Tactile Internet Reference Architecture: Vision and Progress of the IEEE P1918.1 Standard

The term Tactile Internet broadly refers to a communication network which is capable of delivering control, touch, and sensing/actuation information in real-time. The Tactile Internet is currently a topic of interest for various standardization bodies. The emerging IEEE P1918.1 standards working group is focusing on defining a framework for the Tactile Internet. The main objective of this article is to present a reference architecture for the Tactile Internet based on the latest developments within the IEEE P1918.1 standard. The article provides an in-depth treatment of various architectural aspects including the key entities, the interfaces, the functional capabilities and the protocol stack. A case study has been presented as a manifestation of the architecture. Performance evaluation demonstrates the impact of functional capabilities and the underlying enablers on user-level utility pertaining to a generic Tactile Internet application.

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arXiv2018

X-FDR: A Cross-Layer Routing Protocol for Multi-hop Full-Duplex Wireless Networks

The recent developments in self-interference (SI) cancellation techniques have led to the practical realization of full-duplex (FD) radios that can perform simultaneous transmission and reception. FD technology is attractive for various legacy communications standards. In this paper, after discussing the opportunities of FD technology at the network layer, we present a cross-layer aided routing protocol, termed as X-FDR, for multi-hop FD wireless networks. X-FDR exploits a Physical (PHY) layer model capturing imperfection of SI cancellation. At the medium access control (MAC) layer, X-FDR adopts an optimized MAC protocol which implements a power control mechanism without creating the hidden terminal problem. X-FDR exploits the unique characteristics of FD technology at the network layer to construct energy-efficient and low end-to-end latency routes in the network. Performance evaluation demonstrates the effectiveness of X-FDR in achieving the gains of FD at higher layers of the protocol stack.

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arXiv2017

Simultaneous Transmit and Receive Operation in Next Generation IEEE 802.11 WLANs: A MAC Protocol Design Approach

Full-duplex (FD) technology is likely to be adopted in various legacy communications standards. The IEEE 802.11ax working group has been considering a simultaneous transmit and receive (STR) mode for the next generation wireless local area networks (WLANs). Enabling STR mode (FD communication mode) in 802.11 networks creates bi-directional FD (BFD) and uni-directional FD (UFD) links. The key challenge is to integrate STR mode with minimal protocol modifications, while considering the co-existence of FD and legacy half-duplex (HD) stations (STAs) and backwards compatibility. This paper proposes a simple and practical approach to enable STR mode in 802.11 networks with co-existing FD and HD STAs. The protocol explicitly accounts for the peculiarities of FD environments and backwards compatibility. Key aspects of the proposed solution include FD capability discovery, handshake mechanism for channel access, node selection for UFD transmission, adaptive acknowledgement (ACK) timeout for STAs engaged in BFD or UFD transmission, and mitigation of contention unfairness. Performance evaluation demonstrates the effectiveness of the proposed solution in realizing the gains of FD technology for next generation WLANs.

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arXiv2017

Coop-RPL: A Cooperative Approach to RPL-based Routing in Smart Grid AMI Networks

The next generation of electric grid has a scalable and reliable bi-directional communication infrastructure known as Advanced Metering Infrastructure (AMI) to allow monitoring and controlling of grid resources. In this kind of communication system, comprising thousands of resource-constrained nodes such as smart meters, the routing protocol plays a critical role to guarantee reliability and low latency for data delivery. The Routing Protocol for Low Power and Lossy Networks (RPL) currently is standardized by IETF which is expected to meet the requirements of AMI networks as the standard routing protocol. On the other hand, cooperative routing has gained a lot of attention recently. Cooperative routing improves performance over traditional routing by exploiting the broadcasting nature of wireless channels. Our objective in this paper is to propose a cooperative approach to RPL for application in AMI networks. Our proposed protocol, termed as Coop-RPL, is specially designed for the challenges of AMI networks. Coop-RPL ensures reliable packet transmission by selecting an optimal relay node. Performance evaluation demonstrates the efficiency of Coop-RPL for AMI networks with the aim of achieving increased PDR, and reduced number of retransmissions and end-to-end delay.

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arXiv2017

Comments on "CRB-RPL: A Receiver-based Routing Protocol for Communications in Cognitive Radio Enabled Smart Grid"

A recent paper by Yang et al. [1] proposed CRB-RPL as a new RPL-based routing protocol for communications in cognitive radio (CR) enabled smart grid. Essentially, CRB-RPL adopts the operation of CRB-MAC, which is a medium access control (MAC) protocol for cognitive machine-to-machine (M2M) communications, and depicts it as a network layer enhancement. CRB-RPL suffers from a number of technical flaws in terms of protocol operation and analytical aspects. The main objective of this paper is to highlight these technical flaws of CRB-RPL and provide corrections to analytical modeling.

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arXiv2015

Realizing the Tactile Internet: Haptic Communications over Next Generation 5G Cellular Networks

Prior Internet designs encompassed the fixed, mobile and lately the things Internet. In a natural evolution to these, the notion of the Tactile Internet is emerging which allows one to transmit touch and actuation in real-time. With voice and data communications driving the designs of the current Internets, the Tactile Internet will enable haptic communications, which in turn will be a paradigm shift in how skills and labor are digitally delivered globally. Design efforts for both the Tactile Internet and the underlying haptic communications are in its infancy. The aim of this article is thus to review some of the most stringent design challenges, as well as proposing first avenues for specific solutions to enable the Tactile Internet revolution.

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arXiv2015

On Practical Aspects of Mobile Data Offloading to Wi-Fi Networks

Data traffic over cellular networks is exhibiting an ongoing exponential growth, increasing by an order of magnitude every year and has already surpassed voice traffic. This increase in data traffic demand has led to a need for solutions to enhance capacity provision, whereby traffic offloading to Wi-Fi is one means that can enhance realised capacity. Though offloading to Wi-Fi networks has matured over the years, a number of challenges are still being faced by operators to its realization. In this article, we carry out a survey of the practical challenges faced by operators in data traffic offloading to Wi-Fi networks. We also provide recommendations to successfully address these challenges.

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arXiv2015

A Green Perspective on Wi-Fi Offloading

Due to increased energy consumption and carbon emissions of the ICT industry, operators worldwide are focusing on reducing energy consumption of their networks from financial as well as corporate responsibility perspectives. The subject of green or energy efficient operation of cellular access network has attracted a lot of attention in the research community recently. In this regard, dynamically powering down the radio network equipment has emerged as a promising solution. In literature, research around this type of techniques has mainly focused on quantifying the energy saving potential. However, little efforts have been made towards practical realization of these energy saving concepts. On the other hand, Wi-Fi networks are undergoing a paradigm shift towards ubiquity. The main objective of this paper is to provide novel mechanisms for practically realizing the concept of improving power efficiency in the cellular access network through opportunistically offloading users to Wi- Fi networks. These mechanisms are based on the principles of cognitive network management. Performance evaluation shows the potential of proposed mechanisms as a viable solution for achieving energy efficiency in the cellular access network.

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