Search

Accurate indoor positioning remains an open research question. Existing solutions are either expensive, short-range, or inaccurate. A new approach is therefore required to cost-effectively and accurately support localization in large indoor environments. We tackle this problem by introducing a practical optical localization scheme, called OSLo, that cost-effectively scales to support large buildings. OSLo uses a meshed network of low-cost cameras as localization anchors and smart LEDs as tags, which transmit their IDs and context sensor data over the meshed cameras using optical communication. OSLo is capable of localizing dense deployments of tags with an accuracy of under 1 meter at a distance of 35 meters from the localization anchor. Furthermore, smart LED tags can be manufactured for less than $1. We systematically evaluate the performance of OSLo in the context of a real-world car localization use-case at Ford Motor Company in Germany and demonstrate promising results in terms of detection distance, and localization accuracy. ispartof: pages:139-148 ispartof: 22nd IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM) pages:139-148 ispartof: IEEE WoWMoM location:Pisa, Italy date:7 Jun - 11 Jun 2021 status: Published online

The Internet of Things (IoT) is being deployed at large scale in a wide range of long-life applications. Examples range from Industry 4.0 to smart lighting systems. These applications have diverse requirements of non-volatile storage. However, the flash memory that is used in today’s IoT devices offers limited write endurance and must therefore be carefully managed if applications are to deliver on their promises of multiyear lifetimes. Managing the health of flash memory is difficult for application developers, as it requires in-depth hardware and software knowledge, which often needs to the problem being neglected. While various techniques have been proposed to preserve the health of flash memory, prior work tends to focus on a single hardware platform and data type. Furthermore, prior work does not provide lifetime guarantees. This paper tackles this problem by proposing MicroVault, a simple and unified interface for reliable non-volatile data storage on resource-constrained IoT devices. MicroVault enforces developer-specified lifetime guarantees through a range of lifetime extension techniques, which are adaptively applied based upon the needs of the application. Evaluation shows that MicroVault dramatically extends the lifetime of flash memory while minimising overhead.

Remote Attestation (RA) is a security service that detects malware presence on remote IoT devices by verifying their software integrity by a trusted party (verifier). There are three main types of RA: software (SW)-, hardware (HW)-, and hybrid (SW/HW)-based. Hybrid techniques obtain secure RA with minimal hardware requirements imposed on the architectures of existing microcontrollers units (MCUs). In recent years, considerable attention has been devoted to hybrid techniques since prior software-based ones lack concrete security guarantees in a remote setting, while hardware-based approaches are too costly for low-end MCUs. However, one key problem is that many already deployed IoT devices neither satisfy minimal hardware requirements nor support hardware modifications, needed for hybrid RA.This paper bridges the gap between software-based and hybrid RA by proposing a novel RA scheme based on software virtualization. In particular, it proposes a new scheme, called SIMPLE, which meets the minimal hardware requirements needed for secure RA via reliable software. SIMPLE depends on a formally-verified software-based memory isolation technique, called Security MicroVisor (Sμ V). Its reliability is achieved by extending the formally-verified safety and correctness properties to cover the entire software architecture of SIMPLE. Furthermore, SIMPLE is used to construct SIMPLE+, an efficient swarm attestation scheme for static and dynamic heterogeneous IoT networks. We implement and evaluate SIMPLE and SIMPLE+ on Atmel AVR architecture, a common MCU platform.

Massive multiple inputs multiple outputs (MIMO) will be the main physical layer technology of 5G systems. Its idea is to use, for each cell, a large number of antennas to increase the network's performances. In order to improve the throughput, 5G system will be aims to use massive MIMO technique in a dense network. In this article, we focus on the study of the uplink massive MIMO system with small cells. The system performances are modeled and optimized. Simulation results show that using massive MIMO with small cells greatly improves the throughput and number of active users in the cellular networks.

Modern automotive architectures are complex and often comprise of hundreds of electronic control units (ECUs). These ECUs provide diverse services including infotainment, telematics, diagnostics, advanced driving assistance, and many others. The availability of such services is mainly attained by the increasing connectivity with the external world, thus expanding the attack surface. In recent years, automotive original equipment manufacturers (OEMs) and ECU suppliers have become cautious of cyber attacks and have begun fortifying the most vulnerable systems, with hardware-based security modules that enable sandboxing, secure boot, secure software updates and end-to-end message authentication. Nevertheless, insecure legacy ECUs are still in-use in modern vehicles due to price and design complexity issues. Legacy ECUs depend on simple microcontrollers, that lack any kind of hardware-based security. This makes it essential to bridge the gap between modern and legacy ECUs through software-based security by which cyber attacks can be mitigated, thus enhancing the security of vehicles. This paper provides one more step towards highly secure vehicles by introducing a lightweight software-based security framework which provides legacy ECUs with software-based virtualization and protection features along with custom security services. We discuss the motivation for pure software-based approaches, explore the various requirements and advantages obtained, and give an initial insight of the design rationale. Furthermore, we provide a proof of concept implementation and evaluation with a demonstrative use case illustrating the importance of such framework in delivering new diagnostics security services to legacy ECUs. ispartof: pages:1-5 ispartof: IEEE Connected and Autonomous Vehicles Symposium pages:1-5 ispartof: Connected and Automated Vehicles Symposium (CAVS 2019) location:Honolulu, Hawaii, USA date:22 Sep - 23 Sep 2019 status: published

The Cloud Radio Access Network (C-RAN) has clearly emerged as a promising evolution of wireless networks. This architecture consists in decoupling the baseband units (BBUs) from the remote radio heads (RRHs). The BBUs are pooled in the same centralized BBU pool, while the RRHs are distributed through different distant sites. Typically, the one-to-one logical mapping consists in assigning one BBU to one RRH so that distinct frames are generated for each RRH. Also, a logical mapping of one BBU to many RRHs could be established in order to deliver the same frames of a single BBU to a cluster of RRHs. Motivated by the network slicing concept, we propose a hybrid transmission strategy where the resource units (RUs) of each frame are partitioned in two slices. The first one constitutes the unshared slice and is allocated to the cell center users (CCUs) according to the one-to-one logical mapping. The second slice is constituted by a quantity of RUs shared by a cluster of RRHs that belong to the same BBU. This last common slice is transmitted according to the one-to-many mapping in order to be allocated to the cell edge users (CEUs) and to the mobile users (MUs). We also present a flexible solution that dynamically adjusts the BBU-RRH mapping scheme (i.e., one-to-one, one-to-many or hybrid) based on the radio resource usage of BBUs. On the one hand, our proposed solution achieves close packet delay to the one-to-one configuration, while providing lower power consumption and handover frequency. On the other hand, in comparison with the one-to-many configuration, our technique provides lower packet delay and subsequently better Quality of Service (QoS).

Inter-Cell Interference Coordination (ICIC) techniques are proposed as solutions to alleviate the negative impact of interference on system performance, while enhancing the provided Quality of Service (QoS). Typically, the available bandwidth is divided into inner and edge sub-bands. Users are also classified into interior and edge users. The available resources in each zone are exclusively allocated to users belonging to this zone. Mobile users classification is usually based on a threshold that can be either a given mean SINR value or a given distance. However, ICIC approaches based on these static parameters cannot efficiently manage non-homogeneous distribution of users. In this paper, we introduce a dynamic handoff algorithm that aims to adapt static ICIC schemes to uneven distribution of users. Our new solution dynamically computes the classification of active users into interior and edge users, based on a heuristic load balancing algorithm. In our proposal, each cell autonomously reconfigures its bandwidth allocation constraints without modifying bandwidth repartition across the cellular network. This makes the solution well adapted to the non-uniform repartition of users at the multi-cell scale. Simulation results show that the proposed scheme improves bandwidth usage, reduces packet delay, and increases user satisfaction compared to state-of-the-art ICIC techniques.

In this paper, subcarrier allocation problems of wireless Frequency Division Multiple Access systems is studied. The goal of this paper is to introduce new iterative scheduling algorithm for wireless OFDMA systems. These scheduling algorithm maximizes system throughput and guarantees a minimum quality of service for each user. The proposed scheduler is compared to the most used resource allocation algorithms in terms of performance and computational complexity. Based on the simulation results, we note that the proposed scheduling algorithm improves the wireless OFDMA systems performances compared to the classical scheduling methods.

We propose a Wiener-Hammerstein (W-H) channel estimation algorithm for Long-Term Evolution (LTE) systems. The LTE standard provides known data as pilot symbols and exploits them through coherent detection to improve system performance. These drivers are placed in a hybrid way to cover up both time and frequency domain. Our aim is to adapt the W-H equalizer (W-H/E) to LTE standard for compensation of both linear and nonlinear effects induced by power amplifiers and multipath channels. We evaluate the performance of the W-H/E for a Downlink LTE system in terms of BLER, EVM and Throughput versus SNR. Afterwards, we compare the results with a traditional Least-Mean Square (LMS) equalizer. It is shown that W-H/E can significantly reduce both linear and nonlinear distortions compared to LMS and improve LTE Downlink system performance.

In this paper, the principles of coherent optical Fast-OFDM and the modem design with the employment of a Wiener-Hammerstein equalizer (W-H/E) are described. Afterwards, we test 16QAM Fast-OFDM with W-H/E for up to 3500 km of transmission. Finally, we compare coherent optical Fast-OFDM with conventional CO-OFDM using W-H/E.

In this work, we propose a Full Volterra channel equalization for downlink LTE system. For estimation purpose, the LTE standard provides known data as pilots symbols and exploits them through a coherent detection to improve system performance. These drivers are placed in a hybrid way to cover up both time and frequency domain. Our aim is to precise how to adapt the Full Volterra technique to the LTE standard in order to compensate linear and nonlinear effects introduced by power amplifier and multipath channel. We present the comportment of Full Volterra equalizer in term of BLER, EVM (%) and Throughput versus SNR. Then we compare our results with basic RLSequalizercurves. Moreover, it is shown that the Full Volterra model can significantly reduce interferences and nonlinear effects and consequently improves the performances of LTE Downlink System.

It is well known that HARQ technique generates delays du to the retransmissions. Thus, the high speed real time services quality, in High Speed Downlink Packet Access (HSDPA), depends on the number of the retransmissions. Motivated by the important diversity that multiple transmitting antennas and multiple receiving antennas (MIMO) can provide, we study the possibility to avoid HARQ retransmissions by using evolved detector as Multipath Parallel Interference Canceller (MPIC) associated to MIMO. Based on generalized Alamouti codes, then, we demonstrate that MIMO 4×4 + MPIC detector could give better performance than MIMO 2×2 Space-time Rake taking into account the HARQ context.

In this paper, we evaluate by computer simulation the performance of the WCDMA enhanced uplink system with cooperative chip-level hybrid ARQ (HARQ) Chase combining technique over a multi-path Raleigh channels. The fixed relaying protocol used is the amplify-and-forward (AF). At each HARQ retransmission, one relay amplifies and forwards it received signal to the destination. At the node B, relay transmissions are seen as additional receive antennas which are jointly combined at chip-level using a space-time linear minimum square error (LMMSE). The simulation results demonstrate that the performance of the cooperative chip-level Chase combining is better than the non-cooperative chip-level Chase combining when the equivalent signal to noise ratio (SNR) of the inter-users channel and the cooperative channel is superior to the SNR of the direct channel.