In this paper, we present a simple path loss prediction model for link budget analysis in indoor ... more In this paper, we present a simple path loss prediction model for link budget analysis in indoor wireless local area networks (LANs) that use heating, ventilation, and air conditioning (HVAC) cylindrical ducts in 2.4-2.5 GHz frequency band. The model we propose predicts the average power loss between a transmitter-receiver pair in an HVAC duct network. This prediction model greatly simplifies the analysis for a complex duct network, making it a convenient and simple tool for system design. The accuracy of our prediction model is verified by an extensive set of experimental measurements.
Heating, ventilation, and air conditioning (HVAC) ducts in buildings behave as multimode waveguid... more Heating, ventilation, and air conditioning (HVAC) ducts in buildings behave as multimode waveguides when excited at radio frequencies and thus, can be used to distribute radio signals. The channel properties of the ducts are different from the properties of a usual indoor propagation channel. In this paper, we describe physical mechanisms which affect the HVAC channel impulse response and analyze their influence on the delay spread. Those mechanisms include antenna coupling, attenuation, and three types of dispersion: intramodal, intermodal, and multipath. We analyze each type separately and explore the behavior of the delay spread as a function of distance in straight ducts. Experimental channel measurements taken on real ducts confirm the validity of our model.
We report a novel technique for inexpensive high-speed Internet access in buildings. Our work sho... more We report a novel technique for inexpensive high-speed Internet access in buildings. Our work shows that, one can use heating, ventilation, and air conditioning (HVAC) ducts for indoor wireless transmission systems and networks. Measurements and system calculations show that coverage distances in excess of 100 meters from the base station and data rates of up to 100 Mbps should be possible, when HVAC system is used in conjunction with OFDM technology
A common feature of all wireless mobile data networks is the dynamic nature of the propagation en... more A common feature of all wireless mobile data networks is the dynamic nature of the propagation environment. Our work introduces a new level of intelligence into wireless networks by creating a realtime prediction model that runs independently on each mobile node. Such a prediction can assist the routing protocol in making hand-offs or in choosing the best route to a destination, taking into account future RF propagation conditions. Hardware Control (power, antenna, thresholds, etc.)
IEEE Transactions on Microwave Theory and Techniques, 2003
This paper presents a novel technique for analyzing the mode content excited by antennas placed i... more This paper presents a novel technique for analyzing the mode content excited by antennas placed in multimode waveguides. The technique is based on measuring the frequency response between the two antennas coupled into a waveguide and using that information to extract the mode content generated by the transmitting antenna. The technique is applicable to cases in which the mode amplitudes are approximately constant over the frequency range of interest. This method is valuable for determining the mode mix generated by arbitrary transmitting antennas in a multimode waveguide propagation environment. An example of such an environment is heating, ventilation, and air-conditioning (HVAC) ducts used for indoor communications, where an important antenna characteristic is the mode sensitivity (analogous to the antenna directive gain in free space). We validate our technique with the example of a monopole probe antenna coupled into a multimode cylindrical HVAC duct.
Packet level network protocol simulators use simple channel models for computational efficiency. ... more Packet level network protocol simulators use simple channel models for computational efficiency. A typical method for doing this is to compute a packet error probability assuming a certain fading distribution without taking into account time-correlation. This paper introduces work that has been done to model the effect of small-scale fading (Rayleigh and Ricean) within the ns network simulator. It allows for the faithful simulation of a complete fading envelope. The fading models have the appropriate statistics and also time correlational properties obtained from the Doppler spectrum. An efficient implementation based on a simple table lookup is described.
In this paper, we report theoretical channel capacity estimates of heating, ventilation, and air-... more In this paper, we report theoretical channel capacity estimates of heating, ventilation, and air-conditioning (HVAC) ducts based on multi-carrier transmission that uses M-QAM modulation and measured channel responses at 2.4 GHz Industrial, Scientific, and Medical (ISM) band. It is shown that, data rates in excess of 1 Gbps are possible over distances up to 500 m in "matched" ducts (one can think of "matched" ducts as user-friendly ducts, since "matching" can, in principle, eliminate all the multi-path reflections in HVAC ducts). Our work also shows that data rates in excess of 300 Mbps are possible over distances up to 500 m even in the presence of significant multi-path reflections.
IEEE Transactions on Antennas and Propagation, 2003
Heating, ventilation, and air conditioning (HVAC) ducts in buildings are typically hollow metal p... more Heating, ventilation, and air conditioning (HVAC) ducts in buildings are typically hollow metal pipes which can be used as waveguides to carry signals and provide the network access to offices. Knowledge of channel properties is crucial to designing such a communication system. This paper presents a propagation model for a straight HVAC duct terminated at both ends. At high frequencies this duct behaves as a multimode waveguide with a transmitting antenna coupling in and a receiving antenna coupling out. We derive a simple analytical expression for the frequency response of this channel using conventional techniques. Experimental data taken on real circular ducts excited by monopole probe antennas confirm theoretical results. This model represents an initial step toward the development of a tool for planning a wireless distribution system using building HVAC ducts.
In this paper, we describe a UHF radio-frequencyidentification tag test and measurement system ba... more In this paper, we describe a UHF radio-frequencyidentification tag test and measurement system based on National Instruments LabVIEW-controlled PXI RF hardware. The system operates in 800-1000-MHz frequency band with a variable output power up to 30 dBm and is capable of testing tags using Gen2 and other protocols. We explain testing methods and metrics, describe in detail the construction of our system, show its operation with real tag measurement examples, and draw general conclusions.
IEEE Transactions on Circuits and Systems I-regular Papers, 2007
We present for the first time, a fully integrated battery powered RFID integrated circuit (IC) fo... more We present for the first time, a fully integrated battery powered RFID integrated circuit (IC) for operation at ultrahigh frequency (UHF) and microwave bands. The battery powered RFID IC can also work as a passive RFID tag without a battery or when the battery has died (i.e., voltage has dropped below 1.3 V); this novel dual passive and battery operation allays one of the major drawbacks of currently available active tags, namely that the tag cannot be used once the battery has died. When powered by a battery, the current consumption is 700 nA at 1.5 V (400 nA if internal signals are not brought out on testpads). This ultra-low-power consumption permits the use of a very small capacity battery of 100 mA hr for lifetimes exceeding ten years; as a result a battery tag that is very close to a passive tag both in form factor and cost is made possible. The chip is built on a 1m digital CMOS process with dual poly layers, EEPROM and Schottky diodes. The RF threshold power at 2.45 GHz is -19 dBm which is the lowest ever reported threshold power for RFID tags and has a range exceeding 3.5 m under FCC unlicensed operation at the 2.4-GHz microwave band. The low threshold is achieved with architectural choices and low-power circuit design techniques. At 915 MHz, based on the experimentally measured tag impedance (92-j837) and the threshold spec of the tag (200 mV), the theoretical minimum range is 24 m. The tag initially is in a "low-power" mode to conserve power and when issued the appropriate command, it operates in "full-power" mode. The chip has on-chip voltage regulators, clock and data recovery circuits, EEPROM and a digital state machine that implements the ISO 18000-4 B protocol in the "full-power" mode. We provide detailed explanation of the clock recovery circuits and the implementation of the binary sort algorithm, which includes a pseudorandom number generator. Other than the antenna board and a battery, no external components are used.
... Pavel V. Nikitin, Rene Martinez, Shashi Ramamurthy, Hunter Leland, Gary Spiess, and KVS Rao I... more ... Pavel V. Nikitin, Rene Martinez, Shashi Ramamurthy, Hunter Leland, Gary Spiess, and KVS Rao Intermec Technologies Corporation 6001 36th Ave W, Everett, WA, 98203, USA {pavel.nikitin, rene.martinez, shashi.ramamurthy, hunter.leland, gary.spiess, kvs.rao}@intermec.com ...
IEEE Transactions on Microwave Theory and Techniques, 2009
In this paper, we describe the sensitivity and impedance measurement method for UHF RF identifica... more In this paper, we describe the sensitivity and impedance measurement method for UHF RF identification (RFID) chips. The measurements are performed using an RFID tester (RFID reader with variable output power and frequency) and a vector network analyzer. No special impedance matching is required: chips can be connected to standard 50-connectors allowing the sensitivity and threshold impedance to be measured directly in a fast and efficient way. We present experimental data for two UHF Gen2 chips (NXP UCODE G2XM and Impinj Monza 2) in thin-shrink small outline packages. The results have been verified using two chip assemblies matched to 50 . This method can also be applied to chips in other packages: flip-chip, strap, etc.
In this paper, we present a simple path loss prediction model for link budget analysis in indoor ... more In this paper, we present a simple path loss prediction model for link budget analysis in indoor wireless local area networks (LANs) that use heating, ventilation, and air conditioning (HVAC) cylindrical ducts in 2.4-2.5 GHz frequency band. The model we propose predicts the average power loss between a transmitter-receiver pair in an HVAC duct network. This prediction model greatly simplifies the analysis for a complex duct network, making it a convenient and simple tool for system design. The accuracy of our prediction model is verified by an extensive set of experimental measurements.
Heating, ventilation, and air conditioning (HVAC) ducts in buildings behave as multimode waveguid... more Heating, ventilation, and air conditioning (HVAC) ducts in buildings behave as multimode waveguides when excited at radio frequencies and thus, can be used to distribute radio signals. The channel properties of the ducts are different from the properties of a usual indoor propagation channel. In this paper, we describe physical mechanisms which affect the HVAC channel impulse response and analyze their influence on the delay spread. Those mechanisms include antenna coupling, attenuation, and three types of dispersion: intramodal, intermodal, and multipath. We analyze each type separately and explore the behavior of the delay spread as a function of distance in straight ducts. Experimental channel measurements taken on real ducts confirm the validity of our model.
We report a novel technique for inexpensive high-speed Internet access in buildings. Our work sho... more We report a novel technique for inexpensive high-speed Internet access in buildings. Our work shows that, one can use heating, ventilation, and air conditioning (HVAC) ducts for indoor wireless transmission systems and networks. Measurements and system calculations show that coverage distances in excess of 100 meters from the base station and data rates of up to 100 Mbps should be possible, when HVAC system is used in conjunction with OFDM technology
A common feature of all wireless mobile data networks is the dynamic nature of the propagation en... more A common feature of all wireless mobile data networks is the dynamic nature of the propagation environment. Our work introduces a new level of intelligence into wireless networks by creating a realtime prediction model that runs independently on each mobile node. Such a prediction can assist the routing protocol in making hand-offs or in choosing the best route to a destination, taking into account future RF propagation conditions. Hardware Control (power, antenna, thresholds, etc.)
IEEE Transactions on Microwave Theory and Techniques, 2003
This paper presents a novel technique for analyzing the mode content excited by antennas placed i... more This paper presents a novel technique for analyzing the mode content excited by antennas placed in multimode waveguides. The technique is based on measuring the frequency response between the two antennas coupled into a waveguide and using that information to extract the mode content generated by the transmitting antenna. The technique is applicable to cases in which the mode amplitudes are approximately constant over the frequency range of interest. This method is valuable for determining the mode mix generated by arbitrary transmitting antennas in a multimode waveguide propagation environment. An example of such an environment is heating, ventilation, and air-conditioning (HVAC) ducts used for indoor communications, where an important antenna characteristic is the mode sensitivity (analogous to the antenna directive gain in free space). We validate our technique with the example of a monopole probe antenna coupled into a multimode cylindrical HVAC duct.
Packet level network protocol simulators use simple channel models for computational efficiency. ... more Packet level network protocol simulators use simple channel models for computational efficiency. A typical method for doing this is to compute a packet error probability assuming a certain fading distribution without taking into account time-correlation. This paper introduces work that has been done to model the effect of small-scale fading (Rayleigh and Ricean) within the ns network simulator. It allows for the faithful simulation of a complete fading envelope. The fading models have the appropriate statistics and also time correlational properties obtained from the Doppler spectrum. An efficient implementation based on a simple table lookup is described.
In this paper, we report theoretical channel capacity estimates of heating, ventilation, and air-... more In this paper, we report theoretical channel capacity estimates of heating, ventilation, and air-conditioning (HVAC) ducts based on multi-carrier transmission that uses M-QAM modulation and measured channel responses at 2.4 GHz Industrial, Scientific, and Medical (ISM) band. It is shown that, data rates in excess of 1 Gbps are possible over distances up to 500 m in "matched" ducts (one can think of "matched" ducts as user-friendly ducts, since "matching" can, in principle, eliminate all the multi-path reflections in HVAC ducts). Our work also shows that data rates in excess of 300 Mbps are possible over distances up to 500 m even in the presence of significant multi-path reflections.
IEEE Transactions on Antennas and Propagation, 2003
Heating, ventilation, and air conditioning (HVAC) ducts in buildings are typically hollow metal p... more Heating, ventilation, and air conditioning (HVAC) ducts in buildings are typically hollow metal pipes which can be used as waveguides to carry signals and provide the network access to offices. Knowledge of channel properties is crucial to designing such a communication system. This paper presents a propagation model for a straight HVAC duct terminated at both ends. At high frequencies this duct behaves as a multimode waveguide with a transmitting antenna coupling in and a receiving antenna coupling out. We derive a simple analytical expression for the frequency response of this channel using conventional techniques. Experimental data taken on real circular ducts excited by monopole probe antennas confirm theoretical results. This model represents an initial step toward the development of a tool for planning a wireless distribution system using building HVAC ducts.
In this paper, we describe a UHF radio-frequencyidentification tag test and measurement system ba... more In this paper, we describe a UHF radio-frequencyidentification tag test and measurement system based on National Instruments LabVIEW-controlled PXI RF hardware. The system operates in 800-1000-MHz frequency band with a variable output power up to 30 dBm and is capable of testing tags using Gen2 and other protocols. We explain testing methods and metrics, describe in detail the construction of our system, show its operation with real tag measurement examples, and draw general conclusions.
IEEE Transactions on Circuits and Systems I-regular Papers, 2007
We present for the first time, a fully integrated battery powered RFID integrated circuit (IC) fo... more We present for the first time, a fully integrated battery powered RFID integrated circuit (IC) for operation at ultrahigh frequency (UHF) and microwave bands. The battery powered RFID IC can also work as a passive RFID tag without a battery or when the battery has died (i.e., voltage has dropped below 1.3 V); this novel dual passive and battery operation allays one of the major drawbacks of currently available active tags, namely that the tag cannot be used once the battery has died. When powered by a battery, the current consumption is 700 nA at 1.5 V (400 nA if internal signals are not brought out on testpads). This ultra-low-power consumption permits the use of a very small capacity battery of 100 mA hr for lifetimes exceeding ten years; as a result a battery tag that is very close to a passive tag both in form factor and cost is made possible. The chip is built on a 1m digital CMOS process with dual poly layers, EEPROM and Schottky diodes. The RF threshold power at 2.45 GHz is -19 dBm which is the lowest ever reported threshold power for RFID tags and has a range exceeding 3.5 m under FCC unlicensed operation at the 2.4-GHz microwave band. The low threshold is achieved with architectural choices and low-power circuit design techniques. At 915 MHz, based on the experimentally measured tag impedance (92-j837) and the threshold spec of the tag (200 mV), the theoretical minimum range is 24 m. The tag initially is in a "low-power" mode to conserve power and when issued the appropriate command, it operates in "full-power" mode. The chip has on-chip voltage regulators, clock and data recovery circuits, EEPROM and a digital state machine that implements the ISO 18000-4 B protocol in the "full-power" mode. We provide detailed explanation of the clock recovery circuits and the implementation of the binary sort algorithm, which includes a pseudorandom number generator. Other than the antenna board and a battery, no external components are used.
... Pavel V. Nikitin, Rene Martinez, Shashi Ramamurthy, Hunter Leland, Gary Spiess, and KVS Rao I... more ... Pavel V. Nikitin, Rene Martinez, Shashi Ramamurthy, Hunter Leland, Gary Spiess, and KVS Rao Intermec Technologies Corporation 6001 36th Ave W, Everett, WA, 98203, USA {pavel.nikitin, rene.martinez, shashi.ramamurthy, hunter.leland, gary.spiess, kvs.rao}@intermec.com ...
IEEE Transactions on Microwave Theory and Techniques, 2009
In this paper, we describe the sensitivity and impedance measurement method for UHF RF identifica... more In this paper, we describe the sensitivity and impedance measurement method for UHF RF identification (RFID) chips. The measurements are performed using an RFID tester (RFID reader with variable output power and frequency) and a vector network analyzer. No special impedance matching is required: chips can be connected to standard 50-connectors allowing the sensitivity and threshold impedance to be measured directly in a fast and efficient way. We present experimental data for two UHF Gen2 chips (NXP UCODE G2XM and Impinj Monza 2) in thin-shrink small outline packages. The results have been verified using two chip assemblies matched to 50 . This method can also be applied to chips in other packages: flip-chip, strap, etc.
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Papers by Pavel Nikitin