Examples described herein relate to backscatter communication systems and methods. Examples are described which include radio frequency communication devices having both backscatter and non-backscatter communication modes, and the re-use of the same hardware components to generate both backscatter and non-backscatter communication signals.
Backscatter communication offers the potential for significant energy savings compared to conventional wireless links such as Bluetooth, Zigbee, WiFi, etc. However, backscatter communication requires the presence of a carrier source in the environment at an appropriate frequency. If such a carrier source is not available in the environment, backscatter communication may not be practical. It is thus desirable to provide a radio frequency communication device with the option to use either backscatter communication, or non-backscatter communication. Such a device could take advantage of the significant energy savings of backscatter communication when a carrier source is available in the environment, while still retaining the ability to communicate when no carrier source is available in the environment.
Examples of radio frequency communication devices are described herein. An example radio frequency communication device may include a backscatter transmitter circuit, a non-backscatter transmitter circuit, and an antenna. The backscatter transmitter circuit and the non-backscatter transmitter circuit may be in communication with the antenna. A single antenna may be used for both backscatter and non-backscatter transmission.
In some examples, a backscatter transmitter circuit may include a transistor and the transistor may modulate the impedance presented to the antenna.
In some examples, a bias signal may be applied to a control terminal of the transistor. The control terminal may be a gate terminal of a field effect transistor (FET) or a base terminal of a bipolar junction transistor.
In some examples, the transistor may modulate the impedance presented to the antenna, and that impedance may be controlled by the bias signal, to form a backscatter transmitter. The same transistor may be used as a power amplifier for a non-backscatter transmitter.
In some examples, the transistor may have a drain voltage or a collector voltage of substantially zero volts when the transistor is being used as a backscatter transmitter.
In some examples, the bias signal may be a baseband signal of a communication standard such as the Bluetooth, Wi-Fi, IEEE 802.11, Zigbee, Z-Wave, or LoRa communication standards.
Examples of a method are described herein. An example method may include determining a communication mode for a radio frequency communication device from among a plurality of modes including a backscatter mode and a non-backscatter mode. In such a method, a bias condition for a transistor may be selected depending on whether the radio frequency communication device is in a backscatter or a non-backscatter mode. Such a determination may be based at least in part on the presence or absence of a carrier signal in the environment near the radio frequency communication device.
Certain details are set forth below to provide a sufficient understanding of described examples. However, it will be clear to one skilled in the art that examples may be practiced without various of these particular details. In some instances, well-known circuits, control signals, timing protocols, and/or software operations have not been shown in detail in order to avoid unnecessarily obscuring the described examples.
In this description, the phrases “conventional wireless transmitter” and “conventional wireless transceiver” should be understood to refer to a non-backscatter wireless transmitter or transceiver respectively. One feature of a non-backscatter wireless transmitter is that such devices produce their own communication carrier. This is in contrast to backscatter based devices which depend on an externally supplied carrier. Such a non-backscatter wireless transmitter or transceiver may implement one or more wireless communication standards, including but not limited to Bluetooth, Bluetooth Low Energy, Zigbee, Z-Wave, Wi-Fi, IEEE 802.11, IEEE 802.15.4, or LoRa.
In this description, a carrier source may refer to either a modulated or un-modulated radio frequency signal which may serve as a carrier for a backscatter communication system. In some examples, the carrier source may be provided specifically for the purpose of serving as a carrier for a backscatter communication system, while in other examples, the carrier source may be an ambient source such as an AM radio, FM radio, digital television, cellular, land-mobile, satellite, or other signal which may be present in the environment.
It should further be appreciated that backscatter modulation may be accomplished by varying the impedance presented to the terminal(s) of an antenna. As is well known in the state of the art, a varying impedance presented to the terminals of an antenna will cause a change in the reflection by the antenna of a signal incident on the antenna. If the varying impedance is time-varying, a sequence of different reflection states having a different amplitude and/or phase will thus be created. When a signal from a carrier source is incident on an antenna, such a sequence of different reflection states form a sequence of communication symbols. Such symbols may have a one-bit binary representation, if there are two reflection states. Alternatively, if there are more than two reflection states, a multi-bit binary representation may be used to describe the communication symbols. A sequence of communication symbols can be interpreted by a receiver as a multi-bit message that can thus be transmitted from the radio frequency communication device via such a backscatter communication approach.
Some examples include a hybrid architecture for radio frequency communication devices that re-uses the same hardware to selectively operate in either backscatter or conventional (non-backscatter) modes. In one example, a single FET stage is used as both a Class-C power amplifier for a conventional 2.4 GHz, 1 Mbps GFSK Bluetooth Low Energy transmitter with efficiency of approximately 78%, as well as a 10 Mbps BPSK modulator in an ultra-low power backscatter mode. A transmitter energy consumption of 81 nJ/bit is achieved in the conventional mode, while only 32 pJ/bit is required in the BPSK backscatter mode. The data rate of the backscatter mode can be de-coupled from the conventional mode such that the backscatter link can operate at 10× the rate of the conventional link, while achieving over three orders of magnitude power savings. This approach is equally applicable to other communication standards such as WiFi (IEEE 802.11), Zigbee (IEEE 802.15.4), Z-Wave, LoRa, etc.
Digital bus 105 interconnects the digital logic block 101 to a conventional (non-backscatter) wireless transmitter 102, which may be comprised of a single-chip radio frequency transmitter or transceiver (combined transmitter and receiver). In one example, the transceiver may comprise a Nordic Semiconductor nRF24L01+ transceiver chip although others are suitable for this application. Other transmitter implementations such as discrete or multi-chip transmitters are likewise suitable.
The transmitter 102 provides a transmit signal via a transmit path 106 to a power amplifier (PA) 103. In one example, the power amplifier 103 may be comprised of a common source Class-C power amplifier implemented by a field effect transistor (FET) such as an enhancement mode pseudomorphic high electron mobility transistor (e-pHEMT), although other types of transistors such as conventional FETs or bipolar junction transistors (BJTs) are also suitable. In some examples, the power amplifier 103 may be integrated with the aforementioned transmitter 102 on the same semiconductor substrate.
The output of the power amplifier 103 drives an antenna 104 which may comprise any type of antenna known in the art such as a dipole antenna, a whip antenna, a patch antenna, a planar inverted-F antenna (PIFA), etc.
In some examples, one or more control lines 107, 108 may interconnect the digital logic with the power amplifier to control one or more parameters of the power amplifier. In one example, one or more control lines 107 and 108 from the microcontroller may control a drain bias signal VDD and a gate bias signal VG or VGG to a FET based power amplifier (PA) 103 respectively.
The power amplifier block 103 can be used as both a conventional power amplifier for the signal generated by the conventional wireless transmitter as well as a backscatter modulator for backscatter communication. In such examples, the radio frequency communication device may have at least two modes of operation, one mode of operation corresponding to a conventional (non-backscatter) mode, and another mode of operation corresponding to a backscatter mode. Such a system has the advantages of lower complexity and lower cost than other approaches in which the power amplifier block 103 is not re-used between the two modes.
In a conventional (non-backscatter) communication mode, the conventional wireless transmitter 102 may be enabled, for example via a digital control signal conveyed by digital bus 105. One control line 107 may cause the drain bias signal VDD to be set to a power supply voltage such as 3.3V or 5V. A second control line 108 may cause the gate bias signal (VG) to be set to zero volts to enable Class-C operation of the FET PA. In this mode, the FET stage acts as a common source power amplifier to increase the radio frequency power sent to the antenna 104. Using a pHEMT such as the Avago ATF-54143 device, a 2.4 GHz Class C amplifier may have a gain of approximately 10-15 dB and a maximum (compressed) output power of +17 dBm.
In the backscatter modulator mode, in one example, the conventional wireless transmitter may be shut down via a command from the digital logic 101 via the digital bus 105. Alternatively, a “sleep/wake” control line may be provided from the digital logic 101 to the transmitter 102 to shut down the transmitter 102. In this mode, a control line 107 may cause the drain bias VDD of the power amplifier 103 to be set to substantially zero volts. In this mode, the FET PA will not function as an amplifier. Instead, a sequence of digital symbols, which may comprise a baseband signal, having two or more voltage levels are fed from the digital logic 101 to the gate bias VG on the FET via control line 108. In response to the sequence of symbols, the FET modulates its drain to source impedance. This modulation is in turn applied to the antenna 104 to form a backscatter modulation. The backscatter modulation may take the form of an amplitude shift keying (ASK), phase shift keying (PSK), or combinations thereof such as quadrature amplitude modulation (QAM) or orthogonal frequency division multiplexing (OFDM) signals.
In some examples, the sequence of digital symbols may comprise a baseband signal of a communication standard including, but not limited to Bluetooth, Bluetooth Low Energy, Zigbee, Z-Wave, Wi-Fi, IEEE 802.11, IEEE 802.15.4, or LoRa. In such examples, the backscattered signal from the antenna 104 may be compatible with the communication standard, while retaining the power advantages of the backscatter communication modality.
In a backscatter mode, the carrier source 503 is disabled by a carrier enable signal 507, and the energy incident on the antenna 505 is coupled via the coupler 504 to the modulator 502, and is reflected from the modulator 502 back to the antenna 505 to form a backscattered signal.
In a conventional (non-backscatter) transmission mode, the carrier source 503 is enabled by control signal 507. An optional carrier frequency select signal 508 may be used to select the frequency of the carrier source 503. Further optional control signals may include control over the amplitude and/or phase of the carrier source 503.
Coupler 504 may split the carrier signal 503 into two or more portions according to a coupling fraction determined by the design of the coupler and the terminating impedances at each port. A first portion of the carrier signal from carrier source 503 is coupled via the coupler 504 into the backscatter modulator 502, and the reflected energy therefrom is coupled back through the coupler 504 into the antenna 505. A second portion of the carrier signal is coupled via the coupler 504 directly into the antenna 505. The signal at the antenna 505 port therefore consists of the sum of the modulated first portion and the unmodulated second portion. This combination therefore includes both carrier energy as well as modulation sidebands such as the upper sideband, lower sideband, or both upper and lower sidebands forming a double sideband signal. In some examples, the phases of the first portion and the second portion are controlled such that they at least partially cancel when summed at the antenna 505 port to reduce or eliminate the carrier at the antenna 505 port, leaving only the upper and/or lower modulation sideband(s). In further examples, the phases of the first portion and the second portion are controlled so as to suppress both the carrier and one of the upper and lower sidebands, to yield a single sideband signal.
In some examples, the coupler 504 may comprise a directional coupler. A directional coupler may be fabricated using a printed circuit on the same substrate as the rest of the radio frequency communication device (as in e.g. a pair of coupled microstrip transmission lines) or may alternatively be formed from a component directional coupler. In such examples, the “through” path of the coupler 504 may be disposed between the backscatter modulator 502 and the antenna 505. One end of the “coupled” path may be connected to the carrier source 503. The other end of the “coupled” path may be terminated in a terminating impedance. In such examples, the direction of the termination and the carrier source may be configured so as to at least partially cancel the carrier appearing at the antenna 505 port.
In some examples, the coupler 504 may comprise a transmission line segment, such as a microstrip transmission line segment, disposed between the backscatter modulator 502 and the antenna. The carrier source 503 may then be connected to the transmission line segment via a series element such as a resistor, a capacitor, or an inductor (or combinations thereof) such that the impedance presented by the combination of the series element plus the output impedance of the carrier source 503 may be substantially greater than that of the transmission line segment. In one example, the impedance of the transmission line segment and the antenna may be approximately 50 ohms. The output impedance of the carrier source 503 may also be approximately 50 ohms. A series element comprising a resistor of 1K ohms may be used to ensure that the carrier source 503 does not unduly affect the impedance of the transmission line segment.
In such examples, the carrier source 503 may be disabled for the radio frequency communication device to operate in a backscatter mode. To operate in a conventional (non-backscatter) transmit mode, the carrier source 503 may be enabled, and its frequency may be set by an optional control line or bus under the control of the digital logic 501. The backscatter modulator 502 is then operated to produce different reflection coefficients at the corresponding port of the coupler 504. The resulting impedance matching states at the coupler 504 yield upper and/or lower modulation sideband(s) at the antenna port, which are then transmitted by the system.
In one example, the conventional (non-backscatter) mode, a transmitter 602 generates a band-pass signal with a self-generated carrier, such as a 1 Mbps GFSK Bluetooth Low Energy (BLE) signal, which is amplified by a power amplifier 603 having a FET 607 operating as a Class-C amplifier. The Class-C amplifier may in some examples have a gain of 14 dB and 1 dB compression point (P1 dB) of +15.5 dBm at 2.450 GHz. In saturation, the PA may be capable of up to +17 dBm output with a power added efficiency (PAE) of around 78%. The power amplifier may be driven by a low-cost, low power Nordic Semiconductor nRF24L01+ transceiver chip forming transmitter 602 with a power output of 0 dBm. Using the BLE-specified 1 Mbps GFSK modulation, the PA's measured output power may be +14 dBm while the DC power consumed may be 44 mW, for a PA efficiency of 61%. In this example, given the 81 mW total DC power consumed by the PA and the nRF24L01+, and a 242 μs, 242 bit BLE advertising packet, the conventional-mode energy per bit is 81 nJ/bit.
In the backscatter mode, the transmitter 602 is kept in sleep mode via sleep/wake signal 610 and/or digital bus 606, the drain bias is removed from the FET 607 via the PA drain bias control signal 608, and backscatter signaling is accomplished by modulating the gate bias 609 at a rate limited only by the speed of the digital logic 601. In this mode, the FET 607 functions as a two-state impedance switch to produce two reflection coefficients, ΓA and ΓB, at the antenna 605 port, depending on whether the gate bias voltage 609 is zero volts or 3.3 V respectively. In some examples, the reflection coefficients at the antenna port may be ΓA=0.0083−j0.1579 and ΓB=−0.7040+j0.6343. The difference between these two reflection coefficients, ΔΓ=0.7123−j0.7922, determines the magnitude and phase of the backscattered signal. The power consumption in the backscatter mode is simply the energy required to charge and discharge the sum of the device gate capacitance and the impedance matching capacitances. In one example, the total capacitance is ≈12 pF so an energy of ½*C*V{circumflex over ( )}2=65 pJ is expended to charge the gate. Thus, the energy per bit consumed by the backscatter modulator mode is ≈32.6 pJ/bit on average which is over 1000×lower energy per bit than the radio frequency communication device may consume in the conventional (non-backscatter) mode.
From the foregoing it will be appreciated that, although specific examples have been described herein for purposes of illustration, various modifications may be made while remaining with the scope of the claimed technology. One of ordinary skill in the art will appreciate that the above examples are illustrative and non-limiting in nature. Other variations may be employed, including different types of components or combinations of components for implementing the same or similar functions as one or more of the circuit elements shown herein.
This application claims the benefit under 35 U.S.C. § 119 of the earlier filing date of U.S. Provisional Application Ser. No. 62/472,381 filed Mar. 16, 2017, the entire contents of which are hereby incorporated by reference in their entirety for any purpose.
Number | Name | Date | Kind |
---|---|---|---|
4298280 | Harney | Nov 1981 | A |
4916460 | Powell | Apr 1990 | A |
5220330 | Salvail et al. | Jun 1993 | A |
5321599 | Tanamachi et al. | Jun 1994 | A |
5649296 | Maclellan et al. | Jul 1997 | A |
5663710 | Fasig et al. | Sep 1997 | A |
5784686 | Wu et al. | Jul 1998 | A |
5995040 | Issler et al. | Nov 1999 | A |
6084530 | Pidwerbetsky et al. | Jul 2000 | A |
6094450 | Shockey | Jul 2000 | A |
6243012 | Shober et al. | Jun 2001 | B1 |
6259408 | Brady et al. | Jul 2001 | B1 |
6297696 | Abdollahian et al. | Oct 2001 | B1 |
6611224 | Nysen et al. | Aug 2003 | B1 |
6745008 | Carrender et al. | Jun 2004 | B1 |
6765476 | Steele et al. | Jul 2004 | B2 |
6838989 | Mays | Jan 2005 | B1 |
6870460 | Turner et al. | Mar 2005 | B2 |
6970089 | Carrender | Nov 2005 | B2 |
7180402 | Carrender et al. | Feb 2007 | B2 |
7215976 | Brideglall | May 2007 | B2 |
7358848 | Mohamadi | Apr 2008 | B2 |
7469013 | Bolt et al. | Dec 2008 | B1 |
7535360 | Barink et al. | May 2009 | B2 |
7796016 | Fukuda | Sep 2010 | B2 |
7839283 | Mohamadi et al. | Nov 2010 | B2 |
7961093 | Chiao et al. | Jun 2011 | B2 |
7995685 | Wang et al. | Aug 2011 | B2 |
8026839 | Weber | Sep 2011 | B2 |
8120465 | Drucker | Feb 2012 | B2 |
8170485 | Hulvey | May 2012 | B2 |
8284032 | Lee et al. | Oct 2012 | B2 |
8391824 | Kawaguchi | Mar 2013 | B2 |
8526349 | Fisher | Sep 2013 | B2 |
8797146 | Cook et al. | Aug 2014 | B2 |
8952789 | Dardari | Feb 2015 | B2 |
8971704 | Cavaliere et al. | Mar 2015 | B2 |
9312950 | Deyle | Apr 2016 | B1 |
9357341 | Deyle | May 2016 | B2 |
9680520 | Gollakota et al. | Jun 2017 | B2 |
9973367 | Gollakota et al. | May 2018 | B2 |
10033424 | Gollakota et al. | Jul 2018 | B2 |
10079616 | Reynolds et al. | Sep 2018 | B2 |
20020015436 | Ovard et al. | Feb 2002 | A1 |
20030043949 | O'Toole et al. | Mar 2003 | A1 |
20030133495 | Lerner et al. | Jul 2003 | A1 |
20030174672 | Herrmann | Sep 2003 | A1 |
20040005863 | Carrender | Jan 2004 | A1 |
20040210611 | Gradishar et al. | Oct 2004 | A1 |
20050053024 | Friedrich | Mar 2005 | A1 |
20050099269 | Diorio et al. | May 2005 | A1 |
20050201450 | Volpi et al. | Sep 2005 | A1 |
20050248438 | Hughes | Nov 2005 | A1 |
20050265300 | Rensburg | Dec 2005 | A1 |
20060044147 | Knox et al. | Mar 2006 | A1 |
20060045219 | Wang et al. | Mar 2006 | A1 |
20060082458 | Shanks et al. | Apr 2006 | A1 |
20060087406 | Willins et al. | Apr 2006 | A1 |
20060109127 | Barink et al. | May 2006 | A1 |
20060220794 | Zhu | Oct 2006 | A1 |
20060236203 | Diorio et al. | Oct 2006 | A1 |
20060261952 | Kavounas et al. | Nov 2006 | A1 |
20070018904 | Smith | Jan 2007 | A1 |
20070046434 | Chakraborty | Mar 2007 | A1 |
20070069864 | Bae et al. | Mar 2007 | A1 |
20070096876 | Bridgelall et al. | May 2007 | A1 |
20070109121 | Cohen | May 2007 | A1 |
20070111676 | Trachewsky et al. | May 2007 | A1 |
20070115950 | Karaoguz et al. | May 2007 | A1 |
20070201786 | Wuilpart | Aug 2007 | A1 |
20070210923 | Butler et al. | Sep 2007 | A1 |
20070285245 | Djuric et al. | Dec 2007 | A1 |
20070293163 | Kilpatrick | Dec 2007 | A1 |
20080131133 | Blunt et al. | Jun 2008 | A1 |
20080136646 | Friedrich | Jun 2008 | A1 |
20080165007 | Drago et al. | Jul 2008 | A1 |
20080180253 | Ovard et al. | Jul 2008 | A1 |
20080207357 | Savarese et al. | Aug 2008 | A1 |
20080211636 | O'Toole et al. | Sep 2008 | A1 |
20080225932 | Fukuda | Sep 2008 | A1 |
20080252442 | Mohamadi et al. | Oct 2008 | A1 |
20090201134 | Rofougaran | Aug 2009 | A1 |
20090243804 | Fukuda | Oct 2009 | A1 |
20100156651 | Broer | Jun 2010 | A1 |
20100271188 | Nysen | Oct 2010 | A1 |
20110053178 | Yang | Mar 2011 | A1 |
20110260839 | Cook et al. | Oct 2011 | A1 |
20120001732 | Kawaguchi | Jan 2012 | A1 |
20120002766 | Kawaguchi | Jan 2012 | A1 |
20120051411 | Duron et al. | Mar 2012 | A1 |
20120112885 | Drucker | May 2012 | A1 |
20120245444 | Otis et al. | Sep 2012 | A1 |
20120311072 | Huang et al. | Dec 2012 | A1 |
20120313698 | Ochoa et al. | Dec 2012 | A1 |
20130028305 | Gollakota et al. | Jan 2013 | A1 |
20130028598 | Cavaliere et al. | Jan 2013 | A1 |
20130069767 | Ovard et al. | Mar 2013 | A1 |
20130176115 | Puleston et al. | Jul 2013 | A1 |
20130215979 | Yakovlev et al. | Aug 2013 | A1 |
20130223270 | Cheng | Aug 2013 | A1 |
20130265140 | Gudan et al. | Oct 2013 | A1 |
20130286959 | Lou et al. | Oct 2013 | A1 |
20130322498 | Maquire | Dec 2013 | A1 |
20140016719 | Manku | Jan 2014 | A1 |
20140044233 | Morton | Feb 2014 | A1 |
20140113561 | Maguire | Apr 2014 | A1 |
20140313071 | Mccorkle | Oct 2014 | A1 |
20140364733 | Huang et al. | Dec 2014 | A1 |
20150108210 | Zhou | Apr 2015 | A1 |
20150311944 | Gollakota et al. | Oct 2015 | A1 |
20150381269 | Deyle | Dec 2015 | A1 |
20160094933 | Deyle | Mar 2016 | A1 |
20160266245 | Bharadia et al. | Sep 2016 | A1 |
20160365890 | Reynolds et al. | Dec 2016 | A1 |
20170180075 | Gollakota et al. | Jun 2017 | A1 |
20170180178 | Gollakota et al. | Jun 2017 | A1 |
20170180703 | Kovacovsky et al. | Jun 2017 | A1 |
20170331509 | Gollakota et al. | Nov 2017 | A1 |
20180331865 | Ziv et al. | Nov 2018 | A1 |
20180358996 | Gollakota et al. | Dec 2018 | A1 |
20180375703 | Kellogg et al. | Dec 2018 | A1 |
20190116078 | Gollakota et al. | Apr 2019 | A1 |
Number | Date | Country |
---|---|---|
2976734 | Jan 2016 | EP |
2014153516 | Sep 2014 | WO |
2015123306 | Aug 2015 | WO |
2015123341 | Aug 2015 | WO |
2016100887 | Jun 2016 | WO |
2017027847 | Feb 2017 | WO |
2017132400 | Aug 2017 | WO |
2017176772 | Oct 2017 | WO |
2018075653 | Apr 2018 | WO |
2018187737 | Oct 2018 | WO |
Entry |
---|
US 10,187,177 B2, 01/2019, Gollakota et al. (withdrawn) |
US 10,187,241 B2, 01/2019, Gollakota et al. (withdrawn) |
Cadence, “Cadence Spectre RF Option”, http://www.cadence.com/products/rf/spectre_rf_simulation/pages/default.aspx. (Retrieved Jul. 19, 2018). |
DigiPoints. DigiPoints Series vol. 1 Leader Guide Module 9—Network Architectures. Sep. 18, 2015, pp. 9.i-9.18. |
IEEE, “IEEE Standard for Ethernet”, http://standards.ieee.org/getieee802/download/802.11-2012.pdf., Dec. 28, 2012. |
Maxim Integrated, “2.4GHz to 2.5GHz 802.11 g/b FR Transceiver, PA, and Rx/Tx/Antenna Diversity Switch”, https://datasheets.maximintegrated.com/en/ds/MAX2830.pdf. (Retrieved Jul. 19, 2018). |
Nasa, “A Wi-Fi Reflector Chip to Speed Up Wearables”, http://www.jpl.nasa.gov/news/news.php?feature=4663. Jul. 22, 2015. |
Qualcomm, “AR9462 Single-chip, 2.4/5GHz, 2-stream 802.11a/b/g/n and BT 4.0+HS SoC Solution with SST Technology”, http://www.qca.qualcomm.com/wp-content/uploads/2013/11/AR9462.pdf. (Retrieved Jul. 19, 2018). |
Qualcomm. “QCA4002/4004 Qualcomm low-power Wi-Fi”, http://www.eeworld.com.cn/zt/wireless/downloads/QCA4002-4004FIN.pdf. (Retrieved Jul. 19, 2018). |
Synopsys, “Concurrent Timing, Area, Power and Test Optimization”, http://www.synopsys.com/Tools/Implementation/RTLSynthesis/DesignCompiler/Pages/default.aspx. (Retrieved Jul. 19, 2018). |
U.S. Appl. No. 15/752,214 entitled ‘Backscatter Devices and Network Systems Incorporating Backscatter Devices’ filed Feb. 12, 2018, pp. all. |
Unknown, “Altera de1 fpga development board”, http://www.terasic.com.tw/cgi-bin/page/archive.pl?No=83.(Retrieved Jul. 19, 2018). |
Unknown, “Analog Devices HMC190BMS8/190BMS8E”, https://www.hittite.com/content/documents/data_sheet/hmc190bms8.pdf. (Retrieved Jul. 19, 2018). |
Unknown, “Nest Cam Indoor”, https://nest.com/camera/meet-nest-cam/?dropcam=true. 2018. (Retrieved Jul. 19, 2018). |
“Advanced Television Systems Committee (ATSC) (Sep. 1995) “ATSC Digital Television Standard,” ATSC Doc. A/53, 74 pages”, Sep. 1995. |
“Analog Devices (retrieved Apr. 2016) “ADG919 RF Switch Datasheet,” available online at: http://www.datasheet-pdf.com/PDF/ADG919-Datasheet-AnalogDevices-140819”, Apr. 2016. |
“Analog Devices, Inc. (retrieved Jan. 2016) “ADG902 RF switch datasheet,” available online at: http://www.analog.com/static/imported-files/data_sheets/adg901_902.pdf”, Jan. 2016. |
“Axcera.com (retrieved Jan. 2016) “8VSB vs. COFDM,” available online at: http://www.axcera.com/downloads/technotes-whitepapers/technote_4.pdf”, Jan. 2016. |
“DiBEG (May 2014; retrieved Jan. 2016) “The Launching Country,” available online at: http://www.dibeg.org/world/world.html”, May 2014. |
“E. Inc. (retrieved Apr. 2016) “Universal software radio peripheral,” available online at: http://ettus.com”, Apr. 2016. |
“Encounternet (retrieved Jan. 2016) “The Encounternet Project,” available online at: http://encounternet.net/”, Jan. 2016. |
“Federal Communications Commission (retrieved Jan. 2016) “41 dBu service contours around ASRN 1226015, FCC TV query database,” available online at: http://transition.fcc.gov/fcc-bin/tvq?list=0&facid=69571”, Jan. 2016. |
“STMicroelectronics (Jul. 2012) “TS 881 Datasheet,” 1 page”, Jul. 2012. |
Anthony,, Sebastian , ““Free energy harvesting from TV signals, to power a ubiquitous internet of things””, ExtremeTech, google search, Jul. 8, 2013, 8 pages, Jul. 8, 2013. |
Bharadia, et al., “Backfi: High Throughput WiFi Backscatter”. In Proceedings of the 2015 ACM Conference on Special Interest Group on Data Communication, Aug. 2015. |
Bharadia, et al., ““Full duplex backscatter””, Proceedings of the 12th ACM Workshop on Hot Topics in Networks, Article No. 4, pp. 1-7, Nov. 2013. |
Bharadia, et al., ““Full duplex radios””, Proceedings of the ACM SIGCOMM 2013 (SIGCOMM '13), pp. 375-386, Aug. 2013. |
Bohorquez, et al., ““A 350μW CMOS MSK transmitter and 400μW OOK super-regenerative receiver for medical implant communications””, IEEE Journal of Solid-State Circuits, 44(4):1248-1259, Apr. 2009. |
Buettner, , ““Backscatter Protocols and Energy-Efficient Computing for RF-Powered Devices””, PhD Thesis, University of Washington, Seattle, WA, 144 pages, Retrieved Jan. 2016., 2012. |
Buettner, et al., ““Dewdrop: An energy-aware runtime for computational RFID””, Proceedings of the 8th USENIX Conference on Networked Systems Design and Implementation (NSDI'11), pp. 197-210, Mar. 2011. |
Buettner, et al., ““RFID Sensor Networks with the Intel WISP””, Proceedings of the 6th ACM Conference on Embedded Network Sensor Systems (SenSys '08), pp. 393-394, Nov. 2008. |
Chen, et al., Denis Guangyin Chen et al, “Pulse-Modulation Imaging—Review and Performance Analysis”, IEEE Transactions on Biomedical Circuits and Systems, vol. 5, No. 1, Feb. 2011, at 64. |
Chokshi, et al., “Yes! Wi-Fi and Bluetooth Can Coexist in Handheld Devices”, Emerging and Embedded Business Unit, Marvell Semiconductor, Inc., Mar. 2010. |
Dayhoff, , ““New Policies for Part 15 Devices””, Federal Communications Commission (FCC) Telecommunications Certification Body Council (TCBC) Workshop 2005, 13 pages, May 2005. |
Dementyev, et al., ““Wirelessly Powered Bistable Display Tags””, ACM International Joint Conference on Pervasive and Ubiquitous Computing (UbiComp '13), pp. 383-386, Sep. 2013. |
Dementyev, A. et al., ““A Wearable UHF RFID-Based EEG System””, 2013 IEEE International Conference on RFID (RFID), pp. 1-7, Apr.-May 2013. |
Duarte, et al., ““Full-duplex wireless communications using off-the-shelf radios: Feasibility and first results””, 2010 Conference Record of the 44th Asilomar Conference on Signals, Systems and Computers (ASILOMAR), pp. 1558-1562, Nov. 2010. |
Duarte, , ““Full-duplex Wireless: Design, Implementation and Characterization””, Ph.D. thesis, Rice University, 70 pages, Apr. 2012. |
Duc, et al., “Enhancing Security of EPCGlobal Gen-2 RFID against Traceability and Cloning”, Auto-ID Labs Information and Communication University, Auto-ID Labs White Paper No. WP-SWNET-016, 11 pages, Retrieved Jan. 2016, 2006 copyright. |
Elliott, , ““Average U.S. Home Now Receives a Record 118.6 TV Channels, According to Nielsen””, available online at: http://www.nielsen.com/us/en/insights/pressroom/2008/average_u_s_home.html, Jun. 2008. |
Ensworth, et al., “Every smart phone is a backscatter reader: Modulated backscatter compatibility with bluetooth 4.0 low energy (ble) devices”. 2015 IEEE International Conference on RFID. (Retrieved Jul. 19, 2018). |
Gorlatova, et al., ““Energy harvesting active networked tags (EnHANTs) for ubiquitous object networking””, IEEE Wireless Communications, 17(6):18-25, Dec. 2010. |
Greene, et al., “Intel's Tiny Wi-Fi Chip Could Have a Big Impact”. MIT Technology review, Sep. 21, 2012. |
Guo, et al., ““Virtual full-duplex wireless communication via rapid on-off-division duplex””, 48th Annual Allerton Conference on Communication, Control, and Computing (Allerton), pp. 412-419, Sep.-Oct. 2010. |
Jain, et al., ““Practical, real-time, full duplex wireless””, Proceedings of the 17th Annual International Conference on Mobile Computing and Networking (MobiCom'11), pp. 301-312, Sep. 2011. |
Javed, et al., Sajid Javed et al, Background Subtraction via Superpixel-Based Online Matrix Decomposition With Structured Foreground Constraints, ICCVW '15 Proceedings of the 2015 IEEE International Conference on Computer Vision Workshop, Dec. 2015. |
Johnston, Scott , “Software Defined Radio Hardware Survey”, Oct. 2011, 31 pgs. |
Kellogg, et al., ““Bringing gesture recognition to all devices””, Proceedings of the 11th USENIX Conference on Network Systems Design and Implementation (NSDI'14), pp. 303-316, Apr. 2014. |
Kellogg, et al., “Wi-Fi Backscatter: Internet Connectivity for RF-Powered Devices”, University of Washington, SIGCOMM'14, Aug. 17-22, 2014. |
Khannur, et al., “A Universal UHF RFID reader IC in 0.18-μm CMOS Technology”. Solid-State Circuits, IEEE Journal of, 43(5):1146-1155, May 2008. |
Kim, et al., ““Flush: a reliable bulk transport protocol for multihop wireless networks””, Proceedings of the 5th International Conference on Embedded Networked Sensor Systems (SenSys '07), pp. 351-365, Nov. 2007. |
Kleinrock, et al., ““Packet Switching in Radio Channels: Part I—Carrier Sense Multiple-Access Modes and Their Throughput-Delay Characteristics””, IEEE Transactions on Communications, 23(12):1400-1416, Dec. 1975. |
Kodialam, et al., ““Fast and reliable estimation schemes in RFID systems””, Proceedings of the 12th Annual International Conference on Mobile Computing and Networking (MobiCom '06), pp. 322-333, Sep. 2006. |
Koomey, JG et al., ““Implications of Historical Trends in the Electrical Efficiency of Computing””, IEEE Annals of the History of Computing, 33(3):46-54, Aug. 2011. |
Kuester, et al., ““Baseband Signals and Power in Load-Modulated Digital Backscatter,” IEEE Antenna and Wireless Propagation Letter, vol. II, 2012, pp. 1374-1377, Nov. 2012.” |
Lazarus, , ““Remote, wireless, ambulatory monitoring of implantable pacemakers, cardioverter defibrillators, and cardiac resynchronization therapy systems: analysis of a worldwide database””, Pacing and Clinical Electrophysiology, 30(Suppl 1):S2-S12, Jan. 2007. |
Liang, et al., ““Surviving wi-fi interference in low power zigbee networks””, Proceedings of the 8th ACM Conference on Embedded Networked Sensor Systems (SenSys '10), pp. 309-322, Nov. 2010. |
Liu, et al., ““Ambient Backscatter: Wireless Communication out of Thin Air””, Proceedings of the Association for Computing Machinery (ACM) 2013 Conference on Special Interest Group on Data Communications (SIGCOMM), pp. 39-50, also in ACM SIGCOMM Communication Review, 43(4):39-50, Aug./Oct. 2013. |
Liu, et al., ““Digital Correlation Demodulator Design for RFID Reader Receiver””, IEEE Wireless Communications and Networking Conference (WCNC 2007), pp. 1666-1670, Mar. 2007. |
Liu, et al., ““Enabling Instantaneous Feedback with Full-duplex Backscatter””, Proceedings of the 20th Annual International Conference on Mobile Computing and Networking (MobiCom'14), pp. 67-78, Sep. 2014. |
Lu, et al., “Enfold: Downclocking OFDM in WiFi”. In Proceedings of the 20th annual international conference on Mobile computing and networking, pp. 129-140. ACM, Sep. 2014. |
Lu, et al., “Slomo: Downclocking WiFi Communication”. In NSDI, pp. 255-258, Apr. 2013. |
Mace, , ““Wave reflection and transmission in beams””, Journal of Sound and Vibration, 97(2):237-246, Nov. 1984. |
Manweiler, et al., “Avoiding the Rush Hours: Wifi Energy Management via Traffic Isolation”. In MobiSys, Jul. 2011. |
Mastrototaro, , ““The MiniMed Continuous Glucose Monitoring System””, Diabetes Technology & Therapeutics, 2(Suppl 1):13-18, Dec. 2000. |
Merritt, , “Atheros targets cellphone with Wi-Fi chip”, EE Times (Nov. 2, 2009), http://www.eetimes.com/document.asp?doc_id=1172134. |
Metcalfe, et al., ““Ethernet: Distributed packet switching for local computer networks””, Communications of the ACM, 19(7):395-404, Jul. 1976. |
Mishra, et al., ““Supporting continuous mobility through multi-rate wireless packetization””, Proceedings of the 9th Workshop on Mobile Computing Systems and Applications (HotMobile '08), pp. 33-37, Feb. 2008. |
Mittal, et al., “Empowering developers to estimate app energy consumption”. In MobiCom, Aug. 2012. |
Murray Associates, , “The Great Seal Bug Part 1”, Murray Associates, Mar. 2017. |
Mutti, et al., ““CDMA-based RFID Systems in Dense Scenarios: Concepts and Challenges””, 2008 IEEE International Conference on RFID, pp. 215-222, Apr. 2008. |
Naderiparizi, et al., Saman Naderiparizi etal, “Ultra-Low-Power Wireless Streaming Cameras”, arXiv:1707.08718v1, Jul. 27, 2017, Cornell University Library. |
Navaneethan, et al., Navaneethan, VM. Security Enhancement of Frequency Hopping Spread Spectrum Based on Oqpsk Technique. IOSR Journal of Electronics and Communication Engineering. May 2016. 62. |
Nikitin, et al., ““Passive tag-to-tag communication””, 2012 IEEE International Conference on RFID (RFID), pp. 177-184, Apr. 2012. |
Nikitin, et al., ““Theory and measurement of backscattering from RFID tags””, IEEE Antennas and Propagation Magazine, 48(6):212-218, Dec. 2006. |
Obeid, et al., ““Evaluation of spike-detection algorithms for a brain-machine interface application””, IEEE Transactions on Biomedical Engineering, 51(6):905-911, Jun. 2004. |
Occhiuzzi, et al., ““Modeling, Design and Experimentation of Wearable RFID Sensor Tag””, IEEE Transactions on Antennas and Propagation, 58(8):2490-2498, Aug. 2010. |
Pandey, et al., ““A Sub-100 μ W MICS/ISM Band Transmitter Based on Injection-Locking and Frequency Multiplication””, IEEE Journal of Solid-State Circuits, 46(5):1049-1058, May 2011. |
Parks, et al., ““A wireless sensing platform utilizing ambient RF energy””, 2013 IEEE Topical Conference on Biomedical Wireless Technologies, Networks, and Sensing Systems (BioWireleSS), pp. 154-156, Jan. 2013. |
Parks, Aaron N. et al., “Turbocharging Ambient Backscatter Communication”, SIGCOMM, Aug. 2014, 1-12. |
Pillai, et al., ““An Ultra-Low-Power Long Range Battery/Passive RFID Tag for UHF and Microwave Bands With a Current Consumption of 700 nA at 1.5 V””, IEEE Transactions on Circuits and Systems I: Regular Papers, 54(7):1500-1512, Jul. 2007. |
Proakis, et al., “Digital communications”. 2005. McGraw-Hill, New York. (Retrieved Jul. 19, 2018). |
Qing, et al., ““A folded dipole antenna for RFID””, IEEE Antennas and Propagation Society International Symposium, 1:97-100, Jun. 2004. |
Rabaey, et al., ““PicoRadios for wireless sensor networks: the next challenge in ultra-low power design””, 2002 IEEE International Solid-State Circuits Conference, Digest of Technical Papers (ISSCC), 1:200-201, Feb. 2002. |
Ransford, et al., ““Mementos: system support for long-running computation on RFID-scale devices””, ACM SIGPLAN Notices—Proceedings of the 16th International Conference on Architecturla Support for Programming Languages and Operating Systems (ASPLOS '11), 46(3):159-170, Mar. 2011. |
Rao, KVS et al., ““Antenna design for UHF RFID tags: a review and a practical application””, IEEE Transactions on Antennas and Propagation, 53(12):3870-3876, Dec. 2005. |
Rattner, et al., “Connecting the Future: It's a Wireless World”, Sep. 2013. |
Roy, et al., ““RFID: From Supply Chains to Sensor Nets””, Proceedings of the IEEE, 98(9):1583-1592, Jul. 2010. |
Sample, et al., ““Design of an RFID-Based Battery-Free Programmable Sensing Platform””, IEEE Transactions on Instrumentation and Measurement, 57(11):2608-2615, Nov. 2008. |
Sample, et al., ““Experimental results with two wireless power transfer systems””, IEEE Radio and Wireless Symposium (RAWCON), pp. 16-18, Jan. 2009. |
Seigneuret, et al., ““Auto-tuning in passive UHF RFID tags””, 2010 8th IEEE International NEWCAS Conference (NEWCAS), pp. 181-184, Jun. 2010. |
Sen, et al., ““CSMA/CN: Carrier sense multiple access with collision notification””, Proceedings of the 16th Annual International Conference on Mobile Computing and Networking (MobiCom'10), pp. 25-36, Sep. 2010. |
Smith, JR et al., ““A wirelessly-powered platform for sensing and computation””, ACM International Joint Conference on Pervasive and Ubiquitous Computing (UbiComp 2006), 4206:495-506, Sep. 2006. |
So, et al., ““Multi-channel mac for ad hoc networks; handling multi-channel hidden terminals using a single transceiver””, Proceedings of the 5th ACM International Symposium on Mobile Ad Hoc Networking and Computing, pp. 222-233, May 2004. |
Srinivasan, et al., ““An empirical study of low-power wireless””, ACM Transactions on Sensor Networks (TOSN), vol. 6, Issue 2, Article No. 16, Feb. 2010. |
Thomas, et al., ““A 96 Mbit/sec, 15.5 pJ/bit 16-QAM modulator for UHF backscatter communication””, 2012 IEEE International Conference on RFID (RFID), IEEE RFID Virtual Journal, pp. 185-190, Apr. 2012. |
Tubaishat, et al., ““Sensor networks: an overview””, IEEE Potentials, 22(2):20-23, Apr.-May 2003. |
Walden, , ““Analog-to-digital converter survey and analysis””, IEEE Journal on Selected Areas in Communications, 17(4):539-550, Apr. 1999. |
Welbourne, et al., ““Building the Internet of Things Using RFID: The RFID Ecosystem Experience””, IEEE Internet Computing, 13(3):48-55, May-Jun. 2009. |
Wuu, et al., ““Zero-Collision RFID Tags Identification Based on CDMA””, 5th International Conference on Information Assurance and Security (IAS '09), pp. 513-516, Aug. 2009. |
Yi, et al., ““Analysis and Design Strategy of UHF Micro-Power CMOS Rectifiers for Micro-Sensor and RFID Applications””, IEEE Transactions on Circuits and Systems I: Regular Papers, 54(1):153-166, Jan. 2007. |
Ying, et al., “A System Design for UHF RFID Reader”. In Communication Technology, 2008. ICCT 2008. 11th IEEE International Conference on, pp. 301-304. IEEE, Nov. 2008. |
Zalesky, et al., ““Integrating segmented electronic paper displays into consumer electronic devices””, 2011 IEEE International Conference on Consumer Electronics (ICCE), pp. 531-532, Jan. 2011. |
Zhang, et al., ““Frame retransmissions considered harmful: improving spectrum efficiency using micro-ACKs””, Proceedings of the 18th Annual International Conference on Mobile Computing and Networking (MobiCom '12), pp. 89-100, Aug. 2012. |
Zhang, et al., “EkhoNet: High Speed Ultra Low-power Backscatter for Next Generation Sensors”, School of Computer Science, University of Massachusetts, Amherst, MA 01003, Sep. 2014. |
U.S. Appl. No. 16/343,088 titled “Backscatter Systems, Devices, and Techniques Utilizing CSS Modulation and/or Higher Order Harmonic Cancellation” filed Apr. 18, 2019. |
Number | Date | Country | |
---|---|---|---|
20180269909 A1 | Sep 2018 | US |
Number | Date | Country | |
---|---|---|---|
62472381 | Mar 2017 | US |