Ivo Maljevic - Academia.edu (original) (raw)

Papers by Ivo Maljevic

IEEE Internet of Things Journal, 2023

IEEE Transactions on Vehicular Technology

Digital Threats: Research and Practice

MAC-layer spoofing, also known as identity spoofing, is recognized as a serious problem in many p... more MAC-layer spoofing, also known as identity spoofing, is recognized as a serious problem in many practical wireless systems. IoT systems are particularly vulnerable to this type of attack as IoT devices (due to their various limitations) are often incapable of deploying advanced MAC-layer spoofing prevention and detection techniques, such as cryptographic authentication. Signal-level device fingerprinting is an approach to identity spoofing detection that is highly suitable for sensor-based IoT networks but can be also utilized in many other types of wireless systems. Previous research works on signal-level device fingerprinting have been based on rather simplistic assumptions about both the adversary’s behavior and the operation of the defense system. The goal of our work was to examine the effectiveness of a novel system that combines signal-level device fingerprinting with the principles of Randomized Moving Target Defense (RMTD) when dealing with a very advanced adversary. The ob...

Proceedings of ISSSTA'95 International Symposium on Spread Spectrum Techniques and Applications

In this paper the comparison of error probabilities achieved by four nonlinear diversity combinin... more In this paper the comparison of error probabilities achieved by four nonlinear diversity combining schemes for fast frequency hopping (FFH) BFSK in a fading channel with worst-case partial-band jamming is made. In studied schemes, the quadratic detector samples are nonlinearly combined, forming an adaptive gain control (AGC) receiver, self-normalizing (SNORM) receiver, clipped diversity combining (CDC) receiver and ratio statistic (RS)

2010 IEEE 24th International Conference on Advanced Information Networking and Applications Workshops, 2010

Virtualization technology has enabled applications to be decoupled from the underlying hardware p... more Virtualization technology has enabled applications to be decoupled from the underlying hardware providing the benefits of portability, better control over execution environment and isolation. It has been widely adopted in scientific grids and commercial clouds. Since virtualization, despite its benefits incurs a performance penalty, which could be significant for systems dealing with uncertainty such as High Performance Computing (HPC) applications where jobs have tight deadlines and have dependencies on other jobs before they could run. The major obstacle lies in bridging the gap between performance requirements of a job and performance offered by the virtualization technology if the jobs were to be executed in virtual machines. In this paper, we present a novel approach to optimize job deadlines when run in virtual machines by developing a deadline-aware algorithm that responds to job execution delays in real time, and dynamically optimizes jobs to meet their deadline obligations. Our approaches borrowed concepts both from signal processing and statistical techniques, and their comparative performance results are presented later in the paper including the impact on utilization rate of the hardware resources.

IEEE Journal on Selected Areas in Communications, 1996

The influence of code synchronization errors on the performance of direct-sequence spread-spectru... more The influence of code synchronization errors on the performance of direct-sequence spread-spectrum (DS/SS) communication systems is investigated. Insight is gained in the degradation of some basic performance parameters due to the tracking bias of a noncoherent delay lock loop (DLL). The performance parameters investigated are the bit-error probability, throughput and delay. Numerical results show that for receivers with an early-late spacing of il = 1, using a noncoherent DLL, the results of a system performance analysis in a fast fading environment can be much too optimistic if the tracking errors are ignored.

High data rates, low-power consumption, and low complexity will be the most important parameters ... more High data rates, low-power consumption, and low complexity will be the most important parameters in the design of the nextgeneration mobile terminals. In this paper we are introducing a new paradigm in the design of direct sequence spread spectrum receiver by combining analog and digital signal processing. The main difference with respect to the conventional all-digital receiver design approach is that the proposed mixed analog/digital processing results in a symbol rate sampling rather than the high-rate subchip sampling. Analog signal despreading is the key part of the proposed receiver solution, which is based on a five-port device, a passive RF square-law-type device. It is used to perform two important tasks at the same time, namely, the direct conversion and analog despreading. To achieve lower complexity, the proposed receiver uses rectangular instead of pulse-matched despreading at the cost of only a small performance degradation. Also, we propose a new noncoherent pseudonoi...

2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017

Numerous candidate systems have emerged to address the connectivity requirements of Low Power Wir... more Numerous candidate systems have emerged to address the connectivity requirements of Low Power Wireless Access (LPWA) Internet of Things (IoT) applications for massive Machine Type Communication (MTC). This paper analyzes the radio interface design of LoRaWAN systems operating in the North American 915 MHz licence-exempt frequency band. After providing a detailed overview of LoRaWAN system and connectivity structuring, the performance of LoRaWAN radio interface under the default North American mode of operation is thoroughly analyzed. Specifically, coverage, capacity and End Device (ED) throughput rates are determined for defined LoRaWAN Data Rate (DR) classes. Analysis of the LoRaWAN radio interface reveals a requirement of non-uniform ED distribution to attain maximal coverage and capacity, with the DR class achieving maximal coverage providing 1% of the peak capacity and the DRs providing 76% of the maximal capacity confined within 26% of the peak coverage area.

IEEE Communications Magazine, 2019

In this paper we examine the effect of the unresolvable multipath on the performance of mobile un... more In this paper we examine the effect of the unresolvable multipath on the performance of mobile unit that uses antenna diversity scheme for three different types of tracking algorithms. In the first algorithm, the tracking is performed on the basis of the single antenna output. The second algorithm involves RAKE like tracking, where all antenna outputs are combined before tracking. The last algorithm is based on independent tracking for each antenna. It has been shown that the best performance in terms of bit error rate at the receiver is achieved with independent tracking in the presence of unresolvable multipath.

2004 IEEE 15th International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE Cat. No.04TH8754)

Four different digital delay locked loops for PN code tracking in DS-CDMA systems are compared in... more Four different digital delay locked loops for PN code tracking in DS-CDMA systems are compared in this paper. Three of them, namely coherent, noncoherent and modified tracking schemes are well known. The fourth is the new scheme that we propose here as an alternative to the noncoherent (L2 norm) DLL. The new scheme is based on L1 norms of the early and late correlator output signals that are used to form an error signal. The error signal is used to control the local PN code delay. It has been shown that L1 norm based tracking offers similar performance in terms of tracking jitter to that of L2 norm tracking and as such is a viable candidate for implementation because it is computationally less demanding when implemented on DSPs.

IEEE Communications Magazine

Wireless Personal Communications, 2016

In this paper, we present an original design for an Ethernet switch with crosspoint-queued crossb... more In this paper, we present an original design for an Ethernet switch with crosspoint-queued crossbar switching fabric and analyze its performance. Recently, significant progress has been made on performance analysis of crosspoint queued crossbar switches using analytical and simulation methods. We propose a hardware implementation on the NetFPGA platform that can provide reliable results obtained in an experimental environment. It is shown that the proposed design performs as expected and outperforms reference design under some incoming traffic conditions.

Wireless Personal Communications, 2016

Rapid increase in number and diversity of Internet-connected devices raises many challenges for t... more Rapid increase in number and diversity of Internet-connected devices raises many challenges for the traditional network architecture, which is not designed to support a high level of scalability, real-time data delivery and mobility. To address these issues, in this paper we present a new model of Internet of Things architecture which combines benefits of two emerging technologies: software-defined networking and Fog computing. Software-defined networking implies a logically centralized network control plane, which allows implementation of sophisticated mechanisms for traffic control and resource management. On the other hand, Fog computing enables some data to be analysed and managed at the network edge, thus providing support for applications that require very low and predictable latency. In the paper, we give detailed insight into the system structure and functionality of its main components. We also discuss the benefits of the proposed architecture and its potential services.

Crosspoint queued (CQ) switch architecture has been brought back into focus last year and evaluat... more Crosspoint queued (CQ) switch architecture has been brought back into focus last year and evaluated in several recent papers. In this paper, previous research has been extended to the 16x16 switch behavior under few more nonuniform traffic patterns, in order to finalize some general conclusions. Four selection policies are used to implement scheduler: longest queue first, round-robin, frame based round robin matching and random. From the results of our earlier work and results from this paper, one general conclusion can be derived: the implemented algorithm has no influence on the switch performance with long enough buffers implemented, regardless of switch size and traffic pattern.

Packet delay variation analysis for 32x32 crosspoint queued switch under uniform and IBP arrival ... more Packet delay variation analysis for 32x32 crosspoint queued switch under uniform and IBP arrival traffic are presented in this paper. Different buffer sizes and several scheduling algorithms are observed: longest queue first, round robin, exhaustive round robin and frame based round robin matching. Results show that the least packet delay variation, among observed algorithms, causes round robin algorithm.

2014 22nd Telecommunications Forum Telfor (TELFOR), 2014

Software defined networking (SDN) is a new paradigm for wired networks which cleanly decouples co... more Software defined networking (SDN) is a new paradigm for wired networks which cleanly decouples control and the date plane, leaving all control functionality to logically centralized entity. By centralizing network intelligence it provides better visibility of the network conditions, and hence allows more sophisticated traffic management. In this paper, we investigate how the adoption of SDN concept can improve efficiency of heterogeneous wireless environments. We present architectural solution for SDN-based wireless networks, and elaborate on opportunities it provides from various perspectives. In order to exploit benefits of scalable cloud infrastructure, integration of Network Function Virtualization (NFV) is proposed. In particular, the proposed architectural solution allows fast deployment of new services for network operators, gives flexible content delivery options for application providers, and provides improved quality of experience (QoE) for end users.

ABSTRACT In this paper, the performance analysis of a 2×2 crosspoint queued switch is presented. ... more ABSTRACT In this paper, the performance analysis of a 2×2 crosspoint queued switch is presented. The analysis is performed under the non-admissible traffic pattern, for three scheduling algorithms: round-robin, frame-based-round-robin-matching and longest-queue-first. Throughput, average cell latency and memory requirements for buffer implementation are observed. In addition to these parameters which are usually used for switch performance evaluation, inter-flow fairness is also analyzed. The results show that very long buffers are required in order to achieve good performance under the traffic overload, even for small switches. The longest-queue-first algorithm showed higher throughput and lower memory requirements, but worse latency and fairness than other two observed algorithms.

Packet delay variation analysis for a 32x32 crosspoint queued switch under uniform and IBP arriva... more Packet delay variation analysis for a 32x32 crosspoint queued switch under uniform and IBP arrival traffic is presented in this paper. Different buffer sizes and several scheduling algorithms are observed: longest queue first, round robin, exhaustive round robin and frame based round robin matching. Results show that the least packet delay variation, among observed algorithms, causes round robin algorithm.

IEEE Internet of Things Journal, 2023

IEEE Transactions on Vehicular Technology

Digital Threats: Research and Practice

MAC-layer spoofing, also known as identity spoofing, is recognized as a serious problem in many p... more MAC-layer spoofing, also known as identity spoofing, is recognized as a serious problem in many practical wireless systems. IoT systems are particularly vulnerable to this type of attack as IoT devices (due to their various limitations) are often incapable of deploying advanced MAC-layer spoofing prevention and detection techniques, such as cryptographic authentication. Signal-level device fingerprinting is an approach to identity spoofing detection that is highly suitable for sensor-based IoT networks but can be also utilized in many other types of wireless systems. Previous research works on signal-level device fingerprinting have been based on rather simplistic assumptions about both the adversary’s behavior and the operation of the defense system. The goal of our work was to examine the effectiveness of a novel system that combines signal-level device fingerprinting with the principles of Randomized Moving Target Defense (RMTD) when dealing with a very advanced adversary. The ob...

Proceedings of ISSSTA'95 International Symposium on Spread Spectrum Techniques and Applications

In this paper the comparison of error probabilities achieved by four nonlinear diversity combinin... more In this paper the comparison of error probabilities achieved by four nonlinear diversity combining schemes for fast frequency hopping (FFH) BFSK in a fading channel with worst-case partial-band jamming is made. In studied schemes, the quadratic detector samples are nonlinearly combined, forming an adaptive gain control (AGC) receiver, self-normalizing (SNORM) receiver, clipped diversity combining (CDC) receiver and ratio statistic (RS)

2010 IEEE 24th International Conference on Advanced Information Networking and Applications Workshops, 2010

Virtualization technology has enabled applications to be decoupled from the underlying hardware p... more Virtualization technology has enabled applications to be decoupled from the underlying hardware providing the benefits of portability, better control over execution environment and isolation. It has been widely adopted in scientific grids and commercial clouds. Since virtualization, despite its benefits incurs a performance penalty, which could be significant for systems dealing with uncertainty such as High Performance Computing (HPC) applications where jobs have tight deadlines and have dependencies on other jobs before they could run. The major obstacle lies in bridging the gap between performance requirements of a job and performance offered by the virtualization technology if the jobs were to be executed in virtual machines. In this paper, we present a novel approach to optimize job deadlines when run in virtual machines by developing a deadline-aware algorithm that responds to job execution delays in real time, and dynamically optimizes jobs to meet their deadline obligations. Our approaches borrowed concepts both from signal processing and statistical techniques, and their comparative performance results are presented later in the paper including the impact on utilization rate of the hardware resources.

IEEE Journal on Selected Areas in Communications, 1996

The influence of code synchronization errors on the performance of direct-sequence spread-spectru... more The influence of code synchronization errors on the performance of direct-sequence spread-spectrum (DS/SS) communication systems is investigated. Insight is gained in the degradation of some basic performance parameters due to the tracking bias of a noncoherent delay lock loop (DLL). The performance parameters investigated are the bit-error probability, throughput and delay. Numerical results show that for receivers with an early-late spacing of il = 1, using a noncoherent DLL, the results of a system performance analysis in a fast fading environment can be much too optimistic if the tracking errors are ignored.

High data rates, low-power consumption, and low complexity will be the most important parameters ... more High data rates, low-power consumption, and low complexity will be the most important parameters in the design of the nextgeneration mobile terminals. In this paper we are introducing a new paradigm in the design of direct sequence spread spectrum receiver by combining analog and digital signal processing. The main difference with respect to the conventional all-digital receiver design approach is that the proposed mixed analog/digital processing results in a symbol rate sampling rather than the high-rate subchip sampling. Analog signal despreading is the key part of the proposed receiver solution, which is based on a five-port device, a passive RF square-law-type device. It is used to perform two important tasks at the same time, namely, the direct conversion and analog despreading. To achieve lower complexity, the proposed receiver uses rectangular instead of pulse-matched despreading at the cost of only a small performance degradation. Also, we propose a new noncoherent pseudonoi...

2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017

Numerous candidate systems have emerged to address the connectivity requirements of Low Power Wir... more Numerous candidate systems have emerged to address the connectivity requirements of Low Power Wireless Access (LPWA) Internet of Things (IoT) applications for massive Machine Type Communication (MTC). This paper analyzes the radio interface design of LoRaWAN systems operating in the North American 915 MHz licence-exempt frequency band. After providing a detailed overview of LoRaWAN system and connectivity structuring, the performance of LoRaWAN radio interface under the default North American mode of operation is thoroughly analyzed. Specifically, coverage, capacity and End Device (ED) throughput rates are determined for defined LoRaWAN Data Rate (DR) classes. Analysis of the LoRaWAN radio interface reveals a requirement of non-uniform ED distribution to attain maximal coverage and capacity, with the DR class achieving maximal coverage providing 1% of the peak capacity and the DRs providing 76% of the maximal capacity confined within 26% of the peak coverage area.

IEEE Communications Magazine, 2019

In this paper we examine the effect of the unresolvable multipath on the performance of mobile un... more In this paper we examine the effect of the unresolvable multipath on the performance of mobile unit that uses antenna diversity scheme for three different types of tracking algorithms. In the first algorithm, the tracking is performed on the basis of the single antenna output. The second algorithm involves RAKE like tracking, where all antenna outputs are combined before tracking. The last algorithm is based on independent tracking for each antenna. It has been shown that the best performance in terms of bit error rate at the receiver is achieved with independent tracking in the presence of unresolvable multipath.

2004 IEEE 15th International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE Cat. No.04TH8754)

Four different digital delay locked loops for PN code tracking in DS-CDMA systems are compared in... more Four different digital delay locked loops for PN code tracking in DS-CDMA systems are compared in this paper. Three of them, namely coherent, noncoherent and modified tracking schemes are well known. The fourth is the new scheme that we propose here as an alternative to the noncoherent (L2 norm) DLL. The new scheme is based on L1 norms of the early and late correlator output signals that are used to form an error signal. The error signal is used to control the local PN code delay. It has been shown that L1 norm based tracking offers similar performance in terms of tracking jitter to that of L2 norm tracking and as such is a viable candidate for implementation because it is computationally less demanding when implemented on DSPs.

IEEE Communications Magazine

Wireless Personal Communications, 2016

In this paper, we present an original design for an Ethernet switch with crosspoint-queued crossb... more In this paper, we present an original design for an Ethernet switch with crosspoint-queued crossbar switching fabric and analyze its performance. Recently, significant progress has been made on performance analysis of crosspoint queued crossbar switches using analytical and simulation methods. We propose a hardware implementation on the NetFPGA platform that can provide reliable results obtained in an experimental environment. It is shown that the proposed design performs as expected and outperforms reference design under some incoming traffic conditions.

Wireless Personal Communications, 2016

Rapid increase in number and diversity of Internet-connected devices raises many challenges for t... more Rapid increase in number and diversity of Internet-connected devices raises many challenges for the traditional network architecture, which is not designed to support a high level of scalability, real-time data delivery and mobility. To address these issues, in this paper we present a new model of Internet of Things architecture which combines benefits of two emerging technologies: software-defined networking and Fog computing. Software-defined networking implies a logically centralized network control plane, which allows implementation of sophisticated mechanisms for traffic control and resource management. On the other hand, Fog computing enables some data to be analysed and managed at the network edge, thus providing support for applications that require very low and predictable latency. In the paper, we give detailed insight into the system structure and functionality of its main components. We also discuss the benefits of the proposed architecture and its potential services.

Crosspoint queued (CQ) switch architecture has been brought back into focus last year and evaluat... more Crosspoint queued (CQ) switch architecture has been brought back into focus last year and evaluated in several recent papers. In this paper, previous research has been extended to the 16x16 switch behavior under few more nonuniform traffic patterns, in order to finalize some general conclusions. Four selection policies are used to implement scheduler: longest queue first, round-robin, frame based round robin matching and random. From the results of our earlier work and results from this paper, one general conclusion can be derived: the implemented algorithm has no influence on the switch performance with long enough buffers implemented, regardless of switch size and traffic pattern.

Packet delay variation analysis for 32x32 crosspoint queued switch under uniform and IBP arrival ... more Packet delay variation analysis for 32x32 crosspoint queued switch under uniform and IBP arrival traffic are presented in this paper. Different buffer sizes and several scheduling algorithms are observed: longest queue first, round robin, exhaustive round robin and frame based round robin matching. Results show that the least packet delay variation, among observed algorithms, causes round robin algorithm.

2014 22nd Telecommunications Forum Telfor (TELFOR), 2014

Software defined networking (SDN) is a new paradigm for wired networks which cleanly decouples co... more Software defined networking (SDN) is a new paradigm for wired networks which cleanly decouples control and the date plane, leaving all control functionality to logically centralized entity. By centralizing network intelligence it provides better visibility of the network conditions, and hence allows more sophisticated traffic management. In this paper, we investigate how the adoption of SDN concept can improve efficiency of heterogeneous wireless environments. We present architectural solution for SDN-based wireless networks, and elaborate on opportunities it provides from various perspectives. In order to exploit benefits of scalable cloud infrastructure, integration of Network Function Virtualization (NFV) is proposed. In particular, the proposed architectural solution allows fast deployment of new services for network operators, gives flexible content delivery options for application providers, and provides improved quality of experience (QoE) for end users.

ABSTRACT In this paper, the performance analysis of a 2×2 crosspoint queued switch is presented. ... more ABSTRACT In this paper, the performance analysis of a 2×2 crosspoint queued switch is presented. The analysis is performed under the non-admissible traffic pattern, for three scheduling algorithms: round-robin, frame-based-round-robin-matching and longest-queue-first. Throughput, average cell latency and memory requirements for buffer implementation are observed. In addition to these parameters which are usually used for switch performance evaluation, inter-flow fairness is also analyzed. The results show that very long buffers are required in order to achieve good performance under the traffic overload, even for small switches. The longest-queue-first algorithm showed higher throughput and lower memory requirements, but worse latency and fairness than other two observed algorithms.

Packet delay variation analysis for a 32x32 crosspoint queued switch under uniform and IBP arriva... more Packet delay variation analysis for a 32x32 crosspoint queued switch under uniform and IBP arrival traffic is presented in this paper. Different buffer sizes and several scheduling algorithms are observed: longest queue first, round robin, exhaustive round robin and frame based round robin matching. Results show that the least packet delay variation, among observed algorithms, causes round robin algorithm.