International Journal of Wireless Information Networks, 2020
The IEEE 802.11 standard for wireless local area networking (WLAN), commercially known as Wi-Fi, ... more The IEEE 802.11 standard for wireless local area networking (WLAN), commercially known as Wi-Fi, has become a necessity in our day-today life. Over a billion Wi-Fi access points connect close to hundred billion of IoT devices, smart phones, tablets, laptops, desktops, smart TVs, video cameras, monitors, printers, and other consumer devices to the Internet to enable millions of applications to reach everyone, everywhere. The evolution of Wi-Fi technology also resulted in the first commercial piloting of spread spectrum, high speed optical communications, OFDM, MIMO and mmWave pulse transmission technologies, which then became more broadly adopted by cellular phone and wireless sensor networking industries. The popularity and widespread Wi-Fi deployment in indoor areas further motivated innovation in opportunistic cyberspace applications that exploit the ubiquitous Wi-Fi signals. The RF signal radiated from Wi-Fi access points creates an "RF cloud" accessible to any Wi-Fi equipped device hosting or supporting these opportunistic applications. Wi-Fi positioning and location intelligence were the first popular opportunistic applications of Wi-Fi's RF cloud. Today, researchers are investigating opportunistic applications of Wi-Fi signals for gesture and motion detection as well as authentication and security. This paper provides a holistic overview of the evolution of Wi-Fi technology and its applications as the authors experienced it in the last few decades.
Wireless information networks have become a necessity of our day-today life. Over a billion Wi-Fi... more Wireless information networks have become a necessity of our day-today life. Over a billion Wi-Fi access points, hundreds of thousands of cell towers, and billions of IoT devices, using a variety of wireless technologies, create the infrastructure that enables this technology to access everyone, everywhere. The radio signal carrying the wireless information, propagates from antennas through the air and creates a radio frequency (RF) cloud carrying a huge amount of data that is commonly accessible by anyone. The big data of the RF cloud includes information about the transmitter type and addresses, embedded in the information packets; as well as features of the RF signal carrying the message, such as received signal strength (RSS), time of arrival (TOA), direction of arrival (DOA), channel impulse response (CIR), and channel state information (CSI). We can benefit from the big data contents of the messages as well as the temporal and spatial variations of their RF propagation characteristics to engineer intelligent cyberspace applications. This paper provides a holistic vision of emerging cyberspace applications and explains how they benefit from the RF cloud to operate. We begin by introducing the big data contents of the RF cloud. Then, we explain how innovative cyberspace applications are emerging that benefit from this big data. We classify these applications into three categories: wireless positioning systems, gesture and motion detection technologies, and authentication and security techniques. We explain how Wi-Fi, cell-tower, and IoT wireless positioning systems benefit from big data of the RF cloud. We discuss how researchers are studying applications of RF cloud features for motion, activity and gesture detection for human-computer interaction, and we show how authentication and security applications benefit from RF cloud characteristics.
IEEE Journal on Selected Areas in Communications, 1989
This paper analyzes the benefits of using a decision feedback equalizer (DFE) in the indoor radio... more This paper analyzes the benefits of using a decision feedback equalizer (DFE) in the indoor radio environment and examines the results of performance predictions for different channel modelings. It is found that a QPSK/DFE modem with second-order diversity can operate at a data rate which is an order of magnitude higher than a QPSK modem without equalization. A given set of measured profiles of the channel impulse response is interpreted using continuous and discrete channel models. The continuous channel model is represented by the delay power spectrum and the discrete channel model by the envelope delay power spectrum and the arrival rate of the paths. The sensitivity of the performance to the shape of the delay power spectrum, the shape of the envelope delay power spectrum, and the arrival rate of the paths is analyzed.
techniques in IR communication is discussed. Finally, different IR multiple access techniques use... more techniques in IR communication is discussed. Finally, different IR multiple access techniques used in multi-users environments are reviewed. Limitations for IR Communications The rate of data transmission with IR is limited by three sources: multipath, ambient lights, and transient time of the Light Emitting Diodes (LED's). In this subsection these three limitations are briefly reviewed. Limitation Due to Multipath Analysis of the IR optical channel is based on a simple model. If a surface A radiates W watts per unit surface area, the optical power incident on a photosensitive area A is given by PI:
Analysis of the persistency and birth/death of multipath components of the channel impulse respon... more Analysis of the persistency and birth/death of multipath components of the channel impulse response is essential for performance evaluation of indoor geolocation algorithms using indirect paths for ranging. The use of indirect paths via multipath diversity is particularly important for situations where the direct path gets blocked. In this letter, we propose a statistical model for the spatial behavior of the persistency of multipath components as a mobile moves inside a building. Based on empirical data from a measurement calibrated ray tracing algorithm we show that the persistency in a typical building is modeled by log-logistic distribution rather than commonly assumed exponential distribution and path birth can be modeled as a Poisson distribution.
ABSTRACT This paper analyses the effects of training on the performance of neural network handoff... more ABSTRACT This paper analyses the effects of training on the performance of neural network handoff algorithm in a micro-cellular environment. We first describe the neural network handoff decision algorithm as it is applied to the handoff scenario. Then we introduce the effects and performance of the number of training points used for the chosen algorithm. The performance criterion is the number and location of the handoff.
IEEE Journal on Selected Areas in Communications, 1996
This paper uses the results of ray tracing in a typical indooir test area to compare the performa... more This paper uses the results of ray tracing in a typical indooir test area to compare the performance of major radio transmiission techniques that are used as the air interface in evolving standards and major wireless local area network (WLAN) products. The performance of direct sequence (DS) and frequency hopping spread spectrum (FHSS) in the test area are compared with the performance of multicarrier modems, as well as modems using decision feedback equalization (DFE) and sectored antenna systems (SAS). The validity of using ray tracing for performance evaluation is examined by comparing the results with the results of performance evaluation obtained from the empirical measurement of the channel characteristics. Based on the maximum achievable data rate and minimum power requirement (determined in the test area, operation of all modems in bandlimited and power limited applications are discussed. Gaming Yang (S'94-M'95) was born in Nanjing,
2014 International Conference on Computer, Information and Telecommunication Systems (CITS), 2014
Nowadays the deployment of the Wireless Local Area Network (WLAN) is under the limelight of the a... more Nowadays the deployment of the Wireless Local Area Network (WLAN) is under the limelight of the academic community. In a multi-rate data WLAN, the data rate is a function of the distance from the access point (AP). To extend the coverage of the AP to cover a target terminal outside the AP coverage area, relay nodes are deployed between the AP and the target terminal. Therefore, for a given relationship between the throughput and the distance, and a given distance between the access point and the target receiver, there is a minimum number of nodes that provides the maximum throughput to the target receiver. It is always desirable to optimize the deployment from various aspects. These aspects are application-dependent and they range from energy conservation in sensor networks to throughput and coverage maximization in data networks. This paper presents a novel approach to determine the optimal bounds for the Medium Access Control (MAC) throughput at the target receiver in a multi-hop multi-rate wireless data network. We use the principles of linear programming and a model for the physical layer (PHY) throughput-distance relationship to determine the optimal performance bounds for the MAC throughput of a target terminal as a function of distance from the AP and the number of hops. Additionally, we determine the physical locations for the relays to reach the optimal MAC throughput for a target terminal located at a specific distance from the AP.
International Workshop on Wireless Ad-Hoc Networks, 2004.
Abstract In this paper we present a real-time channel simulation environment for performance eval... more Abstract In this paper we present a real-time channel simulation environment for performance evaluation of the indoor geolocation systems using RSS. The EKAHAU positioning software is used as the test positioning system for performance evaluation. ...
Seamless Interconnection for Universal Services. Global Telecommunications Conference. GLOBECOM'99. (Cat. No.99CH37042)
Handoff is an important issue when considering mobility in heterogeneous telecommunication networ... more Handoff is an important issue when considering mobility in heterogeneous telecommunication networks. During the past ten years, telecommunication networks have emerged as a central strategic component in various fields. Today, added flexibility of the heterogeneous wireless networks in the form of robust inter-technology mobility management schemes and sophisticated algorithms is becoming more important. Also data applications and IP protocols have become more important players when designing future architechtures. This paper gives a novel approach to procedures, algorithms and metrics involved in handoff in heterogeneous wireless networks. A network layer Mobile IP based handoflprocedure between WLAN and GPRS is presented as a case study example.
2008 International Wireless Communications and Mobile Computing Conference, 2008
Abstract The concept of indoor localization has attracted considerable attention in the field of ... more Abstract The concept of indoor localization has attracted considerable attention in the field of positioning. It has been reported that time-of-arrival based localization techniques perform superior compared to received signal strength techniques or angle-of-arrival techniques. ...
The International Series in Engineering and Computer Science
The wireless data communication industry has experienced fast development in the past few years. ... more The wireless data communication industry has experienced fast development in the past few years. With the finalization of new series of IEEE 802.11 and ETSI BRAN HIPERLAN standards, new features have been integrated into the conventional wireless LAN, which was introduced as an alternative of fixed LAN. New emerging technologies, such as HomeRF and Bluetooth, are becoming new impetus for the fast expansion of the market. In this paper, we present an overview of the current status and future trends of wireless data communication systems.
International Journal of Wireless Information Networks, 2020
The IEEE 802.11 standard for wireless local area networking (WLAN), commercially known as Wi-Fi, ... more The IEEE 802.11 standard for wireless local area networking (WLAN), commercially known as Wi-Fi, has become a necessity in our day-today life. Over a billion Wi-Fi access points connect close to hundred billion of IoT devices, smart phones, tablets, laptops, desktops, smart TVs, video cameras, monitors, printers, and other consumer devices to the Internet to enable millions of applications to reach everyone, everywhere. The evolution of Wi-Fi technology also resulted in the first commercial piloting of spread spectrum, high speed optical communications, OFDM, MIMO and mmWave pulse transmission technologies, which then became more broadly adopted by cellular phone and wireless sensor networking industries. The popularity and widespread Wi-Fi deployment in indoor areas further motivated innovation in opportunistic cyberspace applications that exploit the ubiquitous Wi-Fi signals. The RF signal radiated from Wi-Fi access points creates an "RF cloud" accessible to any Wi-Fi equipped device hosting or supporting these opportunistic applications. Wi-Fi positioning and location intelligence were the first popular opportunistic applications of Wi-Fi's RF cloud. Today, researchers are investigating opportunistic applications of Wi-Fi signals for gesture and motion detection as well as authentication and security. This paper provides a holistic overview of the evolution of Wi-Fi technology and its applications as the authors experienced it in the last few decades.
Wireless information networks have become a necessity of our day-today life. Over a billion Wi-Fi... more Wireless information networks have become a necessity of our day-today life. Over a billion Wi-Fi access points, hundreds of thousands of cell towers, and billions of IoT devices, using a variety of wireless technologies, create the infrastructure that enables this technology to access everyone, everywhere. The radio signal carrying the wireless information, propagates from antennas through the air and creates a radio frequency (RF) cloud carrying a huge amount of data that is commonly accessible by anyone. The big data of the RF cloud includes information about the transmitter type and addresses, embedded in the information packets; as well as features of the RF signal carrying the message, such as received signal strength (RSS), time of arrival (TOA), direction of arrival (DOA), channel impulse response (CIR), and channel state information (CSI). We can benefit from the big data contents of the messages as well as the temporal and spatial variations of their RF propagation characteristics to engineer intelligent cyberspace applications. This paper provides a holistic vision of emerging cyberspace applications and explains how they benefit from the RF cloud to operate. We begin by introducing the big data contents of the RF cloud. Then, we explain how innovative cyberspace applications are emerging that benefit from this big data. We classify these applications into three categories: wireless positioning systems, gesture and motion detection technologies, and authentication and security techniques. We explain how Wi-Fi, cell-tower, and IoT wireless positioning systems benefit from big data of the RF cloud. We discuss how researchers are studying applications of RF cloud features for motion, activity and gesture detection for human-computer interaction, and we show how authentication and security applications benefit from RF cloud characteristics.
IEEE Journal on Selected Areas in Communications, 1989
This paper analyzes the benefits of using a decision feedback equalizer (DFE) in the indoor radio... more This paper analyzes the benefits of using a decision feedback equalizer (DFE) in the indoor radio environment and examines the results of performance predictions for different channel modelings. It is found that a QPSK/DFE modem with second-order diversity can operate at a data rate which is an order of magnitude higher than a QPSK modem without equalization. A given set of measured profiles of the channel impulse response is interpreted using continuous and discrete channel models. The continuous channel model is represented by the delay power spectrum and the discrete channel model by the envelope delay power spectrum and the arrival rate of the paths. The sensitivity of the performance to the shape of the delay power spectrum, the shape of the envelope delay power spectrum, and the arrival rate of the paths is analyzed.
techniques in IR communication is discussed. Finally, different IR multiple access techniques use... more techniques in IR communication is discussed. Finally, different IR multiple access techniques used in multi-users environments are reviewed. Limitations for IR Communications The rate of data transmission with IR is limited by three sources: multipath, ambient lights, and transient time of the Light Emitting Diodes (LED's). In this subsection these three limitations are briefly reviewed. Limitation Due to Multipath Analysis of the IR optical channel is based on a simple model. If a surface A radiates W watts per unit surface area, the optical power incident on a photosensitive area A is given by PI:
Analysis of the persistency and birth/death of multipath components of the channel impulse respon... more Analysis of the persistency and birth/death of multipath components of the channel impulse response is essential for performance evaluation of indoor geolocation algorithms using indirect paths for ranging. The use of indirect paths via multipath diversity is particularly important for situations where the direct path gets blocked. In this letter, we propose a statistical model for the spatial behavior of the persistency of multipath components as a mobile moves inside a building. Based on empirical data from a measurement calibrated ray tracing algorithm we show that the persistency in a typical building is modeled by log-logistic distribution rather than commonly assumed exponential distribution and path birth can be modeled as a Poisson distribution.
ABSTRACT This paper analyses the effects of training on the performance of neural network handoff... more ABSTRACT This paper analyses the effects of training on the performance of neural network handoff algorithm in a micro-cellular environment. We first describe the neural network handoff decision algorithm as it is applied to the handoff scenario. Then we introduce the effects and performance of the number of training points used for the chosen algorithm. The performance criterion is the number and location of the handoff.
IEEE Journal on Selected Areas in Communications, 1996
This paper uses the results of ray tracing in a typical indooir test area to compare the performa... more This paper uses the results of ray tracing in a typical indooir test area to compare the performance of major radio transmiission techniques that are used as the air interface in evolving standards and major wireless local area network (WLAN) products. The performance of direct sequence (DS) and frequency hopping spread spectrum (FHSS) in the test area are compared with the performance of multicarrier modems, as well as modems using decision feedback equalization (DFE) and sectored antenna systems (SAS). The validity of using ray tracing for performance evaluation is examined by comparing the results with the results of performance evaluation obtained from the empirical measurement of the channel characteristics. Based on the maximum achievable data rate and minimum power requirement (determined in the test area, operation of all modems in bandlimited and power limited applications are discussed. Gaming Yang (S'94-M'95) was born in Nanjing,
2014 International Conference on Computer, Information and Telecommunication Systems (CITS), 2014
Nowadays the deployment of the Wireless Local Area Network (WLAN) is under the limelight of the a... more Nowadays the deployment of the Wireless Local Area Network (WLAN) is under the limelight of the academic community. In a multi-rate data WLAN, the data rate is a function of the distance from the access point (AP). To extend the coverage of the AP to cover a target terminal outside the AP coverage area, relay nodes are deployed between the AP and the target terminal. Therefore, for a given relationship between the throughput and the distance, and a given distance between the access point and the target receiver, there is a minimum number of nodes that provides the maximum throughput to the target receiver. It is always desirable to optimize the deployment from various aspects. These aspects are application-dependent and they range from energy conservation in sensor networks to throughput and coverage maximization in data networks. This paper presents a novel approach to determine the optimal bounds for the Medium Access Control (MAC) throughput at the target receiver in a multi-hop multi-rate wireless data network. We use the principles of linear programming and a model for the physical layer (PHY) throughput-distance relationship to determine the optimal performance bounds for the MAC throughput of a target terminal as a function of distance from the AP and the number of hops. Additionally, we determine the physical locations for the relays to reach the optimal MAC throughput for a target terminal located at a specific distance from the AP.
International Workshop on Wireless Ad-Hoc Networks, 2004.
Abstract In this paper we present a real-time channel simulation environment for performance eval... more Abstract In this paper we present a real-time channel simulation environment for performance evaluation of the indoor geolocation systems using RSS. The EKAHAU positioning software is used as the test positioning system for performance evaluation. ...
Seamless Interconnection for Universal Services. Global Telecommunications Conference. GLOBECOM'99. (Cat. No.99CH37042)
Handoff is an important issue when considering mobility in heterogeneous telecommunication networ... more Handoff is an important issue when considering mobility in heterogeneous telecommunication networks. During the past ten years, telecommunication networks have emerged as a central strategic component in various fields. Today, added flexibility of the heterogeneous wireless networks in the form of robust inter-technology mobility management schemes and sophisticated algorithms is becoming more important. Also data applications and IP protocols have become more important players when designing future architechtures. This paper gives a novel approach to procedures, algorithms and metrics involved in handoff in heterogeneous wireless networks. A network layer Mobile IP based handoflprocedure between WLAN and GPRS is presented as a case study example.
2008 International Wireless Communications and Mobile Computing Conference, 2008
Abstract The concept of indoor localization has attracted considerable attention in the field of ... more Abstract The concept of indoor localization has attracted considerable attention in the field of positioning. It has been reported that time-of-arrival based localization techniques perform superior compared to received signal strength techniques or angle-of-arrival techniques. ...
The International Series in Engineering and Computer Science
The wireless data communication industry has experienced fast development in the past few years. ... more The wireless data communication industry has experienced fast development in the past few years. With the finalization of new series of IEEE 802.11 and ETSI BRAN HIPERLAN standards, new features have been integrated into the conventional wireless LAN, which was introduced as an alternative of fixed LAN. New emerging technologies, such as HomeRF and Bluetooth, are becoming new impetus for the fast expansion of the market. In this paper, we present an overview of the current status and future trends of wireless data communication systems.
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Papers by K. Pahlavan