To properly acknowledge the individuals who positively impacted my life at WPI, I will resort to ... more To properly acknowledge the individuals who positively impacted my life at WPI, I will resort to using two quotes by David Joseph Schwartz and John Quincy Adams:. .. David Joseph Schwartz: "Here is the basic rule for winning success. Let's mark it in the mind and remember it. The rule is: Success depends on the support of other people. The only hurdle between you and what you want to be is the support of other people." I would like to extend my utmost gratitude to Vice Provost of Research, Prof. Bogdan M. Vernescu who was instrumental in opening a new beginning for my Ph.D. endeavor at WPI. In few occasions that I have had the pleasure of meeting with Prof. Varnescu, he inspired me by his respectful mannerism, his willingness to support, and his sound advice. And more close to home, ECE department, Department Head, Prof. Yehia Massoud resolved my administration issue very quickly and efficiently. I greatly appreciate his whole humble demeanor despite his high scholarly achievements. We have a proverb in IRAN that states: "The more fruitful the tree, the more bent it is" and, on the contrary, a fruitless tree with its light weight stands upright!. .. John Quincy Adams: "If your actions inspire others to dream more, learn more, do more and become more, you are a leader." My advisor, Prof. Kaveh Pahlavan can easily be described by the above quote. With his accomplishment and tenure track for many years, he does not swing his weight against the student and on the contrary, there is no iota of ill-intention towards any student. Under Prof. Pahlavan's leadership, I have greatly benefitted from his selflessness, keenness and visionary ideas. We have shared many laughs and has made this endeavor highly educational and fun. Dedicated to two dearest ladies of my life, my Mother, & my Wife. .. Omar Khayyám, Rubaiyat: "To wisely live your life, you don't need to know much Just remember two main rules for the beginning: You better starve, than eat whatever And better be alone, than with whoever.". . .
2015 International Conference on Computing, Networking and Communications (ICNC), 2015
Indoor navigation using RF signals has attracted tremendous attention in the recent years. Howeve... more Indoor navigation using RF signals has attracted tremendous attention in the recent years. However, indoor localization using RF signaling is very challenging and does not provide adequate precision for many applications. In this paper we use Particle Filter (PF) to integrate the Received Signal Strength (RSS) of WiFi and the Time Of Arrival (TOA) of UWB RF signaling for precise cooperative localization in indoor environment. The choice for PF is due to non-linear and Non-Gaussian channel models for RF localization algorithm. We use channel models for the RSS of WiFi and the TOA of UWB. The performance of the PF results are evaluated in a typical indoor scenario and are compared with the Cramér-Rao-Lower-Bound (CRLB) for Hybrid (UWB & WiFi) in Cooperative (COOP) and non-Cooperative (NCOOP) modes.
A novel statistical angle-of-arrival (AOA) model for indoor geolocation applications is presented... more A novel statistical angle-of-arrival (AOA) model for indoor geolocation applications is presented. The modeling approach focuses on the arrivals of the multipath components with respect to the line-of-sight (LOS) path which is an important component especially when indoor geolocation applications are considered. The model is particularly important for indoor applications where AOA information could be utilized for tracking indirect paths to aid in precise ranging in harsh and dense multipath environments where LOS path might be blocked due to obstructions. The results have been obtained by a measurement calibrated ray-tracing (RT) tool.
Infostation contains a radio transceiver that provides wireless access to portable devices random... more Infostation contains a radio transceiver that provides wireless access to portable devices randomly crossing their coverage area. In this application, the size of the transferred information is a function of the travelling angle of crossing, velocity of the mobile terminal, and the data rate of the Infostation which is a function of the distance between the terminal and the Infostation. This paper provides a general framework to analysis the information transfer during random crossing of the coverage area of an Infostation. This analysis derives the statistics of the average information and throughput as a function of throughput-distance relationship of an Infostation. Utilizing the results of this analysis, performance of Infostation using IEEE 802.11b, g, and n WLAN standard technologies are also compared.
2012 6th International Symposium on Medical Information and Communication Technology (ISMICT), 2012
Body area network is expected to be the next breakthrough invention with great potential due to m... more Body area network is expected to be the next breakthrough invention with great potential due to miniaturization of wireless communication devices. One of the major challenges for design of sensor devices for wireless communications inside human body is the accessibility of the medium for performance evaluation. It is practically impossible to install a development module for a sensor inside the human body and when the sensor designed we need expensive procedure with physician supervisions to examine the performance of the sensors. In this paper, we introduce an interference controllable, repeatable real-time hardware platform for performance evaluation of a typical in-body sensor chipset used in most implant applications (Zarlink ZL70101 ADK operating at 402-405 MHz) utilizing an existing multipath channel emulator (Elektrobit PROPSim TM C8) to analyze the performance of the communication link between a sensor located inside the human body and a body mounted sensor. We show how link quality is analyzed by observing the packet reception rate under three different transmission alternatives.
2015 International Conference on Computing, Networking and Communications (ICNC), 2015
The hybrid localization system applications nowadays not only mitigate the inaccuracy of standalo... more The hybrid localization system applications nowadays not only mitigate the inaccuracy of standalone RF localization approach, but also increase the reliability in the absence of supporting Radio Frequency (RF) infrastructure. One of the outstanding hybrid approaches is the Radio Frequency Identification(RFID) assisted inertial navigation system, which is notable for its low cost, simple implementation and extraordinary accuracy. Previous work on such hybrid system fails to find out the correlation between the deployment of the multiple calibration points and the indoor localization accuracy. In this paper, we use the Android smart phone to build a hybrid localization platform and conduct measurements with multiple RFID calibration tags. Based on the measurement results, we define a mathematical model which includes the calibration point number, RFID tag density and the RFID tag-to-corner distance to describe the deployment effect on the localization accuracy. Such model facilitates the future study on algorithm design, system evaluation and application development.
2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, 2011
Many current and future medical devices are wearable and the human body is used as a carrier for ... more Many current and future medical devices are wearable and the human body is used as a carrier for wireless communication, which implies that the human body is a crucial part of the transmission medium in Body Area Networks (BANs). In order to understand the propagation characteristics of the human body, it is imperative to analyze the Doppler spread spectrum, which is caused by human body motions. Using a network analyzer, Doppler spreads and coherence time of temporal variations caused by human body motions can be measured and analyzed using a single tone waveform for different scenarios in a shielded room. From the narrowband measurement results, the Doppler spread varies approximately from 0.6Hz to 12Hz for different scenarios, the RMS Doppler bandwidth is in the range from 0.6Hz to 4Hz, and the coherence time differs from 20ms to 1s, all of which are measured at the Medical Implant Communication Service (MICS) band, the Industrial Scientific Medical (ISM) band and the Ultra-Wideband (UWB) band. Root mean square fittings of three different functions to received signal strength measurements were performed for different scenarios. Results show that the Gaussian function generally provides a good fitting model, which is independent of center frequencies.
2012 IEEE International Conference on Communications (ICC), 2012
Performance evaluation is an essential step in the development and deployment of an indoor TOA lo... more Performance evaluation is an essential step in the development and deployment of an indoor TOA location system, in order to see the influence of multipath condition on ranging and localization accuracy. For field testing approach, multipath condition is invisible, uncontrollable and unrepeatable. Also it is usually not convenient due to system deployment. This paper presents a multipath visible, controllable and repeatable realtime testbed for indoor TOA location performance evaluation, based on RF channel emulator and Ray-tracing software. The testbed can provide accurate performance evaluation in specific indoor environments or specific multipath conditions without deployment. We evaluate the performance of an IEEE 802.15.4a Standard location system in typical office building with this testbed. The result was compared with the performance obtained in field testing to validate the feasibility of the testbed approach.
2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2013
Localization of Wireless Capsule Endoscope (WCE) inside the small intestine is a very challenging... more Localization of Wireless Capsule Endoscope (WCE) inside the small intestine is a very challenging problem, which is very important for the diagnosis of certain diseases. Previous studies have shown that Time-of-Arrival (TOA) localization can be more effective than Received Signal Strength (RSS) based localization. Performance evaluation of TOA-based localization techniques for WCE requires understanding of wideband RF propagation characteristics from the internals of small intestines. Since these measurements are difficult, we need to resort to simulation techniques and validating the results of simulations with empirical measurements. In this paper, we first validate the measurements of wideband characteristics of RF signals pertinent to TOA in homogeneous tissues using a SEMCAD X simulation software platform. Then we use the software for simulation of TOA from inside the human body and the small intestine. Finally, we analyze and assess TOA techniques regarding the nonhomogeneous environment inside the human body.
2012 6th International Symposium on Medical Information and Communication Technology (ISMICT), 2012
In this paper we analyze the accuracy of narrowband and wideband localization techniques inside t... more In this paper we analyze the accuracy of narrowband and wideband localization techniques inside the homogeneous human tissues using a fast finite difference time domain (FDTD) technique. In the narrowband localization, the phase of the received carrier signal is used for ranging measurements, whereas for the wideband transmission, the time of arrival (TOA) of the received signal is used. For fast computations, we introduce a new perspective to FDTD simulations of radio propagation by considering each simulation set for a given location of antennas as a Linear Time Invariant (LTI) discrete-time system. This way a set of simulations for a variety of transmitted waveforms can be reduced to only one simulation to determine the impulse response of the simulated channel between the two antennas and the convolution of the set of waveforms with this impulse response. A typical simulation using FDTD takes several minutes to a few hours and each convolution takes only a few seconds, resulting in a huge reduction in computational time.
2011 IEEE Topical Conference on Biomedical Wireless Technologies, Networks, and Sensing Systems, 2011
In this paper, we evaluate the factors affecting the accuracy achievable in localization of an en... more In this paper, we evaluate the factors affecting the accuracy achievable in localization of an endoscopic wireless capsule as it passes through the digestive system of the human body. Using a three-dimension full electromagnetic wave simulation model, we obtain bounds on the capsulelocation estimation errors when the capsule is in each of three individual organs: stomach, small intestine and large intestine. The simulations assume two different external sensor arrays topologies. We compare these performance bounds and draw the conclusion that location-estimation errors are different for different organs and for various topologies of the external sensor arrays.
2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012
This paper presents an analysis on localization accuracy of a capsule used for wireless endoscopy... more This paper presents an analysis on localization accuracy of a capsule used for wireless endoscopy application when there are random variations in transmit power of sensor nodes. We use a three-dimensional human body model and the log normal model for Received Signal Strength (RSS) radio propagation from the implant to the sensor nodes on the body surface to find accuracy bounds in three digestive organs, namely stomach, small intestine, and large intestine, which form the human Gastro-Intestinal (GI) track. The analysis is done using Bayesian Crameŕ-Rao bound assuming that the transmit power is random process with known prior distribution. We provide analysis of the factors affecting localization accuracy including various organ environment, external sensor array topology. The simulation results show that the capsule localization inside large intestine is affected the most with the transmit power randomness, while wireless capsule can be localized with best accuracy inside the small intestine. Finally, we propose an approach to improve the attainable accuracy bounds.
International Journal of Embedded and Real-Time Communication Systems, 2012
In this invited paper, the authors introduce an overview of the fundamentals of radio frequency (... more In this invited paper, the authors introduce an overview of the fundamentals of radio frequency (RF) channel measurement and modeling techniques needed for localization inside the human body. To address these fundamentals, the authors use capsule endoscopy as an example application. The authors first provide the results of the Cramer Rao Lower Bound (CRLB) for received signal strength (RSS) based endoscopy capsule localization, inside the human body, using existing path-loss models for radio propagation. Then challenges demanding further research are highlighted for attaining more precise localization using the time-of-arrival (TOA) based ranging techniques.
Compared the measurement results in two different bandwidths, Ultra-wide band (UWB 3-10 GHz) and ... more Compared the measurement results in two different bandwidths, Ultra-wide band (UWB 3-10 GHz) and Narrow Band (NB 402MHz). We figured out the multi path situation by comparing the measurement results in empty flat box and in the homogenous tissue. The maximum distance of the measurement in this paper is 9 cm considering the huge path-loss in UWB measurement. Based on the analysis of the DME, the TOA of the first peak in UWB measurement and the phase of signal in narrowband measurement can both provide the accurate location information for BAN application.
International Journal of Wireless Information Networks, 2012
Many current and future medical devices are wearable and human body is used as a carrier for wire... more Many current and future medical devices are wearable and human body is used as a carrier for wireless communication, which implies human body to be a crucial part of the transmission medium in body area networks (BANs). In order to understand the propagation characteristics around human body, the statistical model is derived for communication links in the medical implant communication service band, industrial scientific medical band and ultra-wideband based on the narrowband measurement. The channel model of diffracting components around human body were different from one scenario to another. Moreover, second order statistics, including level crossing rate and fade duration, are presented for each scenario to evaluate the link quality and outage performance for on-body to on-body scenario. Using a network analyzer, Doppler spread spectrum in frequency domain and coherence time in time domain from temporal variations of human body movements are also analyzed from diverse perspectives. Additionally, the shape of Doppler spread spectrum is fitted to describe the relationship of power and frequency. The proposed on-body to on-body channel model for human body motions can be used to better design wireless network protocols for BANs.
International Journal of Wireless Information Networks, 2012
In this paper, we derive and analyze cooperative localization bounds for endoscopic wireless caps... more In this paper, we derive and analyze cooperative localization bounds for endoscopic wireless capsule as it passes through the human gastrointestinal (GI) tract. We derive the Cramer-Rao bound (CRB) variance limits on location estimators which use measured received signal strength (RSS). Using a three-dimension human body model from a full wave simulation software and log-normal models for RSS propagation from implant organs to body surface, we calculate bounds on location estimators in three digestive organs: stomach, small intestine and large intestine. We provide analysis of the factors affecting localization accuracy, including various organ environments, external sensor array topology, number of pills in cooperation and the random variations in transmit power of sensor nodes. We also do localization accuracy analysis for the case when transmit power of the sensor is random with known priori distribution. The simulation results show that the number of receiver sensors on body surface has more influence on the accuracy of localization than the number of pills in cooperation inside the GI tract, The large intestine is affected the most with the transmit power randomness.
A framework f o r statistical modeling of the wideband character-ABSTRACT istics o f t h e freque... more A framework f o r statistical modeling of the wideband character-ABSTRACT istics o f t h e frequency-selective f a d i n g m u l t i p a t h indoor radio channel f o r geolocation applications is presented. Multipath characteristics o f the channel are divided into three classes according t o availability and the strength of the direct line of sight (DLOS) path w i t h respect t o the other paths. Statistics o f t h e error in estimating the t i m e o f arrival o f t h e DLOS p a t h i n a b u i l d i n g is related t o t h e receiver's sensitivity and dynamic range. The effects of external walls on estimating t h e location o f the DLOS path
... 4(2) (2007) 129141 Sengupta, I., see Datta, R. 4(1) (2007) 6174 Suma, MN, Bybi, PC and Moha... more ... 4(2) (2007) 129141 Sengupta, I., see Datta, R. 4(1) (2007) 6174 Suma, MN, Bybi, PC and Mohanan, P., A Wideband Hybrid Printed Monopole/Rectangular Patch Antenna 4(1) (2007) 5359 Suma, MN, see Joseph, M. 4(1) (2007) 4351 ...
Designations used by companies to distinguish their products are often claimed as trademarks. All... more Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. It is sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom. If professional advice or other expert assistance is required, the services of a competent professional should be sought. MATLAB ® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks does not warrant the accuracy of the text or exercises in this book. This book's use or discussion of MATLAB ® software or related products does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or particular use of the MATLAB ® software.
2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733)
I am also very grateful to my fellow WPI friends, Bardia Alavi, Engin Ayturk, Mohammed Heidari fo... more I am also very grateful to my fellow WPI friends, Bardia Alavi, Engin Ayturk, Mohammed Heidari for their continuous help and support. Their acquaintance has made my experience at WPI a remarkable one. I am extremely grateful to members of the thesis committee, Professor Fred Looft and Professor Wenjing Lou. I also take the opportunity to express my gratitude for the Fulbright Association and AMIDEAST for providing this valuable opportunity which funded my graduate studies.
To properly acknowledge the individuals who positively impacted my life at WPI, I will resort to ... more To properly acknowledge the individuals who positively impacted my life at WPI, I will resort to using two quotes by David Joseph Schwartz and John Quincy Adams:. .. David Joseph Schwartz: "Here is the basic rule for winning success. Let's mark it in the mind and remember it. The rule is: Success depends on the support of other people. The only hurdle between you and what you want to be is the support of other people." I would like to extend my utmost gratitude to Vice Provost of Research, Prof. Bogdan M. Vernescu who was instrumental in opening a new beginning for my Ph.D. endeavor at WPI. In few occasions that I have had the pleasure of meeting with Prof. Varnescu, he inspired me by his respectful mannerism, his willingness to support, and his sound advice. And more close to home, ECE department, Department Head, Prof. Yehia Massoud resolved my administration issue very quickly and efficiently. I greatly appreciate his whole humble demeanor despite his high scholarly achievements. We have a proverb in IRAN that states: "The more fruitful the tree, the more bent it is" and, on the contrary, a fruitless tree with its light weight stands upright!. .. John Quincy Adams: "If your actions inspire others to dream more, learn more, do more and become more, you are a leader." My advisor, Prof. Kaveh Pahlavan can easily be described by the above quote. With his accomplishment and tenure track for many years, he does not swing his weight against the student and on the contrary, there is no iota of ill-intention towards any student. Under Prof. Pahlavan's leadership, I have greatly benefitted from his selflessness, keenness and visionary ideas. We have shared many laughs and has made this endeavor highly educational and fun. Dedicated to two dearest ladies of my life, my Mother, & my Wife. .. Omar Khayyám, Rubaiyat: "To wisely live your life, you don't need to know much Just remember two main rules for the beginning: You better starve, than eat whatever And better be alone, than with whoever.". . .
2015 International Conference on Computing, Networking and Communications (ICNC), 2015
Indoor navigation using RF signals has attracted tremendous attention in the recent years. Howeve... more Indoor navigation using RF signals has attracted tremendous attention in the recent years. However, indoor localization using RF signaling is very challenging and does not provide adequate precision for many applications. In this paper we use Particle Filter (PF) to integrate the Received Signal Strength (RSS) of WiFi and the Time Of Arrival (TOA) of UWB RF signaling for precise cooperative localization in indoor environment. The choice for PF is due to non-linear and Non-Gaussian channel models for RF localization algorithm. We use channel models for the RSS of WiFi and the TOA of UWB. The performance of the PF results are evaluated in a typical indoor scenario and are compared with the Cramér-Rao-Lower-Bound (CRLB) for Hybrid (UWB & WiFi) in Cooperative (COOP) and non-Cooperative (NCOOP) modes.
A novel statistical angle-of-arrival (AOA) model for indoor geolocation applications is presented... more A novel statistical angle-of-arrival (AOA) model for indoor geolocation applications is presented. The modeling approach focuses on the arrivals of the multipath components with respect to the line-of-sight (LOS) path which is an important component especially when indoor geolocation applications are considered. The model is particularly important for indoor applications where AOA information could be utilized for tracking indirect paths to aid in precise ranging in harsh and dense multipath environments where LOS path might be blocked due to obstructions. The results have been obtained by a measurement calibrated ray-tracing (RT) tool.
Infostation contains a radio transceiver that provides wireless access to portable devices random... more Infostation contains a radio transceiver that provides wireless access to portable devices randomly crossing their coverage area. In this application, the size of the transferred information is a function of the travelling angle of crossing, velocity of the mobile terminal, and the data rate of the Infostation which is a function of the distance between the terminal and the Infostation. This paper provides a general framework to analysis the information transfer during random crossing of the coverage area of an Infostation. This analysis derives the statistics of the average information and throughput as a function of throughput-distance relationship of an Infostation. Utilizing the results of this analysis, performance of Infostation using IEEE 802.11b, g, and n WLAN standard technologies are also compared.
2012 6th International Symposium on Medical Information and Communication Technology (ISMICT), 2012
Body area network is expected to be the next breakthrough invention with great potential due to m... more Body area network is expected to be the next breakthrough invention with great potential due to miniaturization of wireless communication devices. One of the major challenges for design of sensor devices for wireless communications inside human body is the accessibility of the medium for performance evaluation. It is practically impossible to install a development module for a sensor inside the human body and when the sensor designed we need expensive procedure with physician supervisions to examine the performance of the sensors. In this paper, we introduce an interference controllable, repeatable real-time hardware platform for performance evaluation of a typical in-body sensor chipset used in most implant applications (Zarlink ZL70101 ADK operating at 402-405 MHz) utilizing an existing multipath channel emulator (Elektrobit PROPSim TM C8) to analyze the performance of the communication link between a sensor located inside the human body and a body mounted sensor. We show how link quality is analyzed by observing the packet reception rate under three different transmission alternatives.
2015 International Conference on Computing, Networking and Communications (ICNC), 2015
The hybrid localization system applications nowadays not only mitigate the inaccuracy of standalo... more The hybrid localization system applications nowadays not only mitigate the inaccuracy of standalone RF localization approach, but also increase the reliability in the absence of supporting Radio Frequency (RF) infrastructure. One of the outstanding hybrid approaches is the Radio Frequency Identification(RFID) assisted inertial navigation system, which is notable for its low cost, simple implementation and extraordinary accuracy. Previous work on such hybrid system fails to find out the correlation between the deployment of the multiple calibration points and the indoor localization accuracy. In this paper, we use the Android smart phone to build a hybrid localization platform and conduct measurements with multiple RFID calibration tags. Based on the measurement results, we define a mathematical model which includes the calibration point number, RFID tag density and the RFID tag-to-corner distance to describe the deployment effect on the localization accuracy. Such model facilitates the future study on algorithm design, system evaluation and application development.
2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, 2011
Many current and future medical devices are wearable and the human body is used as a carrier for ... more Many current and future medical devices are wearable and the human body is used as a carrier for wireless communication, which implies that the human body is a crucial part of the transmission medium in Body Area Networks (BANs). In order to understand the propagation characteristics of the human body, it is imperative to analyze the Doppler spread spectrum, which is caused by human body motions. Using a network analyzer, Doppler spreads and coherence time of temporal variations caused by human body motions can be measured and analyzed using a single tone waveform for different scenarios in a shielded room. From the narrowband measurement results, the Doppler spread varies approximately from 0.6Hz to 12Hz for different scenarios, the RMS Doppler bandwidth is in the range from 0.6Hz to 4Hz, and the coherence time differs from 20ms to 1s, all of which are measured at the Medical Implant Communication Service (MICS) band, the Industrial Scientific Medical (ISM) band and the Ultra-Wideband (UWB) band. Root mean square fittings of three different functions to received signal strength measurements were performed for different scenarios. Results show that the Gaussian function generally provides a good fitting model, which is independent of center frequencies.
2012 IEEE International Conference on Communications (ICC), 2012
Performance evaluation is an essential step in the development and deployment of an indoor TOA lo... more Performance evaluation is an essential step in the development and deployment of an indoor TOA location system, in order to see the influence of multipath condition on ranging and localization accuracy. For field testing approach, multipath condition is invisible, uncontrollable and unrepeatable. Also it is usually not convenient due to system deployment. This paper presents a multipath visible, controllable and repeatable realtime testbed for indoor TOA location performance evaluation, based on RF channel emulator and Ray-tracing software. The testbed can provide accurate performance evaluation in specific indoor environments or specific multipath conditions without deployment. We evaluate the performance of an IEEE 802.15.4a Standard location system in typical office building with this testbed. The result was compared with the performance obtained in field testing to validate the feasibility of the testbed approach.
2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2013
Localization of Wireless Capsule Endoscope (WCE) inside the small intestine is a very challenging... more Localization of Wireless Capsule Endoscope (WCE) inside the small intestine is a very challenging problem, which is very important for the diagnosis of certain diseases. Previous studies have shown that Time-of-Arrival (TOA) localization can be more effective than Received Signal Strength (RSS) based localization. Performance evaluation of TOA-based localization techniques for WCE requires understanding of wideband RF propagation characteristics from the internals of small intestines. Since these measurements are difficult, we need to resort to simulation techniques and validating the results of simulations with empirical measurements. In this paper, we first validate the measurements of wideband characteristics of RF signals pertinent to TOA in homogeneous tissues using a SEMCAD X simulation software platform. Then we use the software for simulation of TOA from inside the human body and the small intestine. Finally, we analyze and assess TOA techniques regarding the nonhomogeneous environment inside the human body.
2012 6th International Symposium on Medical Information and Communication Technology (ISMICT), 2012
In this paper we analyze the accuracy of narrowband and wideband localization techniques inside t... more In this paper we analyze the accuracy of narrowband and wideband localization techniques inside the homogeneous human tissues using a fast finite difference time domain (FDTD) technique. In the narrowband localization, the phase of the received carrier signal is used for ranging measurements, whereas for the wideband transmission, the time of arrival (TOA) of the received signal is used. For fast computations, we introduce a new perspective to FDTD simulations of radio propagation by considering each simulation set for a given location of antennas as a Linear Time Invariant (LTI) discrete-time system. This way a set of simulations for a variety of transmitted waveforms can be reduced to only one simulation to determine the impulse response of the simulated channel between the two antennas and the convolution of the set of waveforms with this impulse response. A typical simulation using FDTD takes several minutes to a few hours and each convolution takes only a few seconds, resulting in a huge reduction in computational time.
2011 IEEE Topical Conference on Biomedical Wireless Technologies, Networks, and Sensing Systems, 2011
In this paper, we evaluate the factors affecting the accuracy achievable in localization of an en... more In this paper, we evaluate the factors affecting the accuracy achievable in localization of an endoscopic wireless capsule as it passes through the digestive system of the human body. Using a three-dimension full electromagnetic wave simulation model, we obtain bounds on the capsulelocation estimation errors when the capsule is in each of three individual organs: stomach, small intestine and large intestine. The simulations assume two different external sensor arrays topologies. We compare these performance bounds and draw the conclusion that location-estimation errors are different for different organs and for various topologies of the external sensor arrays.
2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012
This paper presents an analysis on localization accuracy of a capsule used for wireless endoscopy... more This paper presents an analysis on localization accuracy of a capsule used for wireless endoscopy application when there are random variations in transmit power of sensor nodes. We use a three-dimensional human body model and the log normal model for Received Signal Strength (RSS) radio propagation from the implant to the sensor nodes on the body surface to find accuracy bounds in three digestive organs, namely stomach, small intestine, and large intestine, which form the human Gastro-Intestinal (GI) track. The analysis is done using Bayesian Crameŕ-Rao bound assuming that the transmit power is random process with known prior distribution. We provide analysis of the factors affecting localization accuracy including various organ environment, external sensor array topology. The simulation results show that the capsule localization inside large intestine is affected the most with the transmit power randomness, while wireless capsule can be localized with best accuracy inside the small intestine. Finally, we propose an approach to improve the attainable accuracy bounds.
International Journal of Embedded and Real-Time Communication Systems, 2012
In this invited paper, the authors introduce an overview of the fundamentals of radio frequency (... more In this invited paper, the authors introduce an overview of the fundamentals of radio frequency (RF) channel measurement and modeling techniques needed for localization inside the human body. To address these fundamentals, the authors use capsule endoscopy as an example application. The authors first provide the results of the Cramer Rao Lower Bound (CRLB) for received signal strength (RSS) based endoscopy capsule localization, inside the human body, using existing path-loss models for radio propagation. Then challenges demanding further research are highlighted for attaining more precise localization using the time-of-arrival (TOA) based ranging techniques.
Compared the measurement results in two different bandwidths, Ultra-wide band (UWB 3-10 GHz) and ... more Compared the measurement results in two different bandwidths, Ultra-wide band (UWB 3-10 GHz) and Narrow Band (NB 402MHz). We figured out the multi path situation by comparing the measurement results in empty flat box and in the homogenous tissue. The maximum distance of the measurement in this paper is 9 cm considering the huge path-loss in UWB measurement. Based on the analysis of the DME, the TOA of the first peak in UWB measurement and the phase of signal in narrowband measurement can both provide the accurate location information for BAN application.
International Journal of Wireless Information Networks, 2012
Many current and future medical devices are wearable and human body is used as a carrier for wire... more Many current and future medical devices are wearable and human body is used as a carrier for wireless communication, which implies human body to be a crucial part of the transmission medium in body area networks (BANs). In order to understand the propagation characteristics around human body, the statistical model is derived for communication links in the medical implant communication service band, industrial scientific medical band and ultra-wideband based on the narrowband measurement. The channel model of diffracting components around human body were different from one scenario to another. Moreover, second order statistics, including level crossing rate and fade duration, are presented for each scenario to evaluate the link quality and outage performance for on-body to on-body scenario. Using a network analyzer, Doppler spread spectrum in frequency domain and coherence time in time domain from temporal variations of human body movements are also analyzed from diverse perspectives. Additionally, the shape of Doppler spread spectrum is fitted to describe the relationship of power and frequency. The proposed on-body to on-body channel model for human body motions can be used to better design wireless network protocols for BANs.
International Journal of Wireless Information Networks, 2012
In this paper, we derive and analyze cooperative localization bounds for endoscopic wireless caps... more In this paper, we derive and analyze cooperative localization bounds for endoscopic wireless capsule as it passes through the human gastrointestinal (GI) tract. We derive the Cramer-Rao bound (CRB) variance limits on location estimators which use measured received signal strength (RSS). Using a three-dimension human body model from a full wave simulation software and log-normal models for RSS propagation from implant organs to body surface, we calculate bounds on location estimators in three digestive organs: stomach, small intestine and large intestine. We provide analysis of the factors affecting localization accuracy, including various organ environments, external sensor array topology, number of pills in cooperation and the random variations in transmit power of sensor nodes. We also do localization accuracy analysis for the case when transmit power of the sensor is random with known priori distribution. The simulation results show that the number of receiver sensors on body surface has more influence on the accuracy of localization than the number of pills in cooperation inside the GI tract, The large intestine is affected the most with the transmit power randomness.
A framework f o r statistical modeling of the wideband character-ABSTRACT istics o f t h e freque... more A framework f o r statistical modeling of the wideband character-ABSTRACT istics o f t h e frequency-selective f a d i n g m u l t i p a t h indoor radio channel f o r geolocation applications is presented. Multipath characteristics o f the channel are divided into three classes according t o availability and the strength of the direct line of sight (DLOS) path w i t h respect t o the other paths. Statistics o f t h e error in estimating the t i m e o f arrival o f t h e DLOS p a t h i n a b u i l d i n g is related t o t h e receiver's sensitivity and dynamic range. The effects of external walls on estimating t h e location o f the DLOS path
... 4(2) (2007) 129141 Sengupta, I., see Datta, R. 4(1) (2007) 6174 Suma, MN, Bybi, PC and Moha... more ... 4(2) (2007) 129141 Sengupta, I., see Datta, R. 4(1) (2007) 6174 Suma, MN, Bybi, PC and Mohanan, P., A Wideband Hybrid Printed Monopole/Rectangular Patch Antenna 4(1) (2007) 5359 Suma, MN, see Joseph, M. 4(1) (2007) 4351 ...
Designations used by companies to distinguish their products are often claimed as trademarks. All... more Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. It is sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom. If professional advice or other expert assistance is required, the services of a competent professional should be sought. MATLAB ® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks does not warrant the accuracy of the text or exercises in this book. This book's use or discussion of MATLAB ® software or related products does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or particular use of the MATLAB ® software.
2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733)
I am also very grateful to my fellow WPI friends, Bardia Alavi, Engin Ayturk, Mohammed Heidari fo... more I am also very grateful to my fellow WPI friends, Bardia Alavi, Engin Ayturk, Mohammed Heidari for their continuous help and support. Their acquaintance has made my experience at WPI a remarkable one. I am extremely grateful to members of the thesis committee, Professor Fred Looft and Professor Wenjing Lou. I also take the opportunity to express my gratitude for the Fulbright Association and AMIDEAST for providing this valuable opportunity which funded my graduate studies.
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Papers by Kaveh Pahlavan