CN102299753A - Method of constructing wireless communication device to obtain motion sensing functionality - Google Patents

Abstract

A system for sensing motion and performing wireless communication, comprising: one or more antennas for transmitting and receiving wireless data communication signals and motion detection electromagnetic waves; one or more electrical switches that switch between electrical paths that activate channel scanning, motion sensing, interference detection, and data communication; a motion sensing receiver that receives motion detection electromagnetic waves; a transceiver that generates a modulated RF signal for wireless data communication and an unmodulated RF signal for motion detection, the unmodulated RF signal bypassing the transceiver modulator; one or more processors that process the motion detection electromagnetic wave data and the detected interference signal data, and transmit and process wireless communication data to and from the transceiver, control the one or more electrical switches, and provide commands to the transceiver.

Description

Method of constructing a wireless communication device for motion sensing functionality

technical field

The invention relates to a wireless data communication system and a system utilizing electromagnetic wave motion sensing. More specifically, the present invention relates to a circuit system that performs the dual functions of wireless data communication and motion sensing in a sequentially timed manner.

Background technique

Traditionally, wireless communication devices (eg, a WiFi network access point or adapter in a WiFi network or a portable phone in a cellular communication network) are used only for data or voice communication. Motion detection systems are often implemented individually as stand-alone devices, such as burglar alarm systems and speed radars.

One motion detection technique is based on the Doppler effect. The Doppler effect is the change in wave frequency of an observer moving relative to/away from the wave source. The frequency of the sensed waves is higher when the observer moves closer to the wave source, but lower when the observer moves away from the wave source. The Doppler effect is also applied to some types of radar. Almost all surfaces reflect electromagnetic waves. To detect moving objects, the radio beam is aimed at the target object. The radio beam is reflected back towards the source of the wave. The wavelength of the reflected wave increases if the target object moves further away from the wave source, and decreases if it gets closer. By measuring the individual continuous waves, the velocity of the target object can be calculated.

In a conventional home automation system, appliances such as lighting systems, air conditioners, etc. are connected with wireless communication devices. The most commonly used wireless communication system is the Zigbee specification (a set of high-level communication protocols utilizing small, low-power digital radios based on the IEEE 802.15.4-2003 standard for low-speed wireless personal area networks (LR-WPAN)). In the Zigbee system, electrical appliances are controlled remotely through a handheld controller device or a computer. To save energy and enhance system flexibility, external motion sensors are also connected to appliances that work with wireless communication devices. Such a structure generally results in complicated installation and higher costs.

In more modern systems, it has been achieved to combine wireless data communication and motion detection technologies into a single system because both include the transmission and reception of electromagnetic waves. One can find several practical applications for this combined system. For example, in lighting control, the lights can be turned on and off through the wireless controller, and when no one is in the room, the lights can be turned off automatically. However, most such systems require the simple combination of two disparate parts to form a single unit, or require dedicated circuitry, resulting in high cost and/or a high degree of complexity. An additional benefit of integrating motion sensing functionality into a wireless communication device is that structural parameters such as detection range, sensitivity, channel can be changed with the same wireless controller used for wireless communication. That means there is no need for a separate additional controller for motion sensing. Furthermore, motion sensing enables interactive operations with the environment because the motion sensing function is integrated into the wireless communication device. For example, by using the channel scanning function of the communication device, the motion sensing module can utilize different channels with different signal strengths, enabling multiple motion sensors to operate simultaneously in a small defined area without causing false motion detections.

In US Patent No. 6,084,530, a modulated backscatter sensor system is disclosed. The backscatter sensor system utilizes a radio frequency identification (RFID) tag to facilitate detection of tag motion, which can be attached to a target object. In this publication, the RFID tag itself transmits RF signals (including analog signals) to the sensor. For RFID data communication and Doppler signal analysis, custom circuits were built. Therefore, the system can only be implemented and applied exclusively using RFID technology. Furthermore, in this system, a modulated carrier signal that is sensitive to interference is used for motion sensing.

US Patent Application Publication No. 2008/0056390 discloses a method of estimating the Doppler frequency of a moving mobile communication device and its motion velocity. In this publication, this method is used in a cellular or WLAN communication network with at least one mobile communication device and a plurality of base stations. The wireless communication coverage area is divided into a plurality of areas within which the mobile communication device can maintain sufficient signal strength. When traveling between regions, the signal gets weaker and stronger as the mobile communication device approaches and then moves away from the zero crossing. The Doppler frequency is then calculated from the attenuation of the preamble and pilot signals exchanged between the mobile communication device and the base station. Therefore, the motion sensing feature in this publication is specific to the cellular or WLAN communication network technology and can only detect the motion of the mobile communication device in the communication network.

Another type of motion sensing involves embedding gyrators into mobile communication devices, enabling the mobile device itself to detect its own motion and communicate this information to base stations in the communication network. US Patent Application Publication No. 2008/0238703 discloses such a system. However, such systems cannot be used to detect the motion of random objects.

Therefore, there is a need in the art for an improved wireless communication system that includes integrated motion detection functionality.

Contents of the invention

According to an embodiment of the present invention, the wireless communication system is modified to include additional motion sensor functionality. The present invention provides motion sensing capability by improving upon traditional wireless communication components, avoiding the use of external devices or having to combine two separate sets of devices dedicated to wireless communication and motion detection. This reduces cost and system complexity.

Additionally, the present invention includes transceivers having a single port for transmitting and receiving RF signals. The transceiver is configured to send and receive data communications via a modulated carrier signal, and is also capable of bypassing its modulator to generate an unmodulated carrier signal for motion detection, thus acting as a transmitter of motion sensing signals . An unmodulated carrier signal is less sensitive to disturbances during motion sensing. To improve the accuracy of motion sensing, the system detects interfering signals in one mode of operation by identifying the ambient noise layer in the detection area. In another mode of operation, the system scans the environment for available frequencies and selects the appropriate frequency as the motion-sensing carrier signal. The advantage is that this allows multiple motion sensors in the same detection area while avoiding co-channel and adjacent channel interference.

In one embodiment, a processor, such as a digital signal processor (DSP), is used to process and analyze motion detection electromagnetic wave data and detected jamming signal data from motion sensing receivers, processing wireless communications received from transceivers data, controls one or more electrical switches, and controls and provides output communication data to the transceiver.

According to various embodiments, one or more electrical switches are used to switch between electrical pathways that activate different operations, including ambient channel scanning, motion sensing, interference detection, and wireless data communication signal transmission and reception. In one embodiment, two electrical switches are used to create three electrical paths: a first electrical path, which connects the first antenna to the transceiver, and to the processor, which enables ambient channel scan operations and Data communication operation; second electrical path connecting the first antenna to the coupler and to the transceiver, then to the processor, connecting the second antenna to the motion sensing receiver connected to the coupler, to the processor, This second electrical path is capable of motion sensing operations; a third electrical path that connects the second antenna to the motion sensing receiver connected to the coupler, to the processor, the coupler to the transceiver, to the processing device, the third electrical path is capable of tamper detection operations.

Description of drawings

In the following, embodiments of the present invention are described in more detail with reference to the accompanying drawings, in which:

Fig. 1 shows the structural diagram of the embodiment of the wireless communication system with motion sensing function;

Fig. 2 shows the structural diagram of the embodiment of the wireless communication system with motion sensing function under the environment channel scanning mode of operation and the data communication mode of operation;

3 shows a block diagram of an embodiment of a wireless communication system with motion sensing functionality in a motion detection mode of operation;

4 illustrates a block diagram of an embodiment of a wireless communication system with motion sensing functionality in a jamming detection mode of operation; and

FIG. 5 shows a flowchart of the operation of a wireless communication system with motion sensing functionality.

Detailed ways

In the following description, a wireless communication system having a motion sensing function and the like and its construction method are explained by way of preferred examples. It will be apparent to those skilled in the art that modifications including additions and/or substitutions can be made without departing from the scope and spirit of the invention. Specific details may be omitted in order not to obscure the invention; however, the disclosure is written to enable one skilled in the art to implement the teachings herein without undue experimentation.

Referring to Figure 1, two electrical switches 103 and 104 are used to create 3 electrical paths: a first electrical path, which connects the first antenna 101 to the transceiver 105, and then to the processor 106, which enables Ambient channel scanning operation and data communication operation; second electrical path that connects first antenna 101 to coupler 110, and in parallel to transceiver 105, then to processor 106, second antenna 102 to motion sensing receiver The mixer 108 of 107 is connected to the coupler 110, then connected to the active filter 109 of the motion sensing receiver 107, the coupler 110 is connected to the transceiver 105, then connected to the processor 106, the second electrical path Enables motion sensing operation; a third electrical path that connects the second antenna 102 to the mixer 108 of the motion sensing receiver 107 connected to a coupler 110 connected to the transceiver 105 and then to The processor 106, the third electrical path is capable of performing an interference detection operation.

Ambient channel scan:

Referring to FIG. 2 , in the ambient channel scan mode of operation, the wireless communication system with motion sensing activates the electrical path connecting the first antenna 101 to the transceiver 105 and then to the processor 106 . The system scans through the frequency spectrum and compares the signals at each scanned frequency for their relative signal strength. The processor 106 is configured to control the transceiver 105 to scan the frequency spectrum of the target detection area, and then perform frequency domain analysis on the received signal at each scanning frequency. A frequency with relatively low signal strength is selected as the motion detection carrier signal frequency. This allows multiple motion sensors in the same detection area while avoiding co-channel and adjacent channel interference.

According to one embodiment, the signal strength analysis complies with the IEEE 802.11 standard, in which a value referred to as Received Signal Strength Indicator (RSSI) represents the signal strength of RF signals swept at different frequencies. In "Converting SignalStrength Percentage to dBm Values" of WildPackets in November 2002, a detailed description of the IEEE 802.11 standard and RSSI is disclosed; the contents thereof are incorporated herein by reference in their entirety.

data communication:

Still referring to FIG. 2 , in the data communication mode of operation, the wireless communication system with motion sensing functionality activates an electrical path connecting the first antenna 101 to the transceiver 105 and then to the processor 106 . Processor 106 provides control signals and outgoing communication data to transceiver 105 . Transceiver 105 includes an internal modulator and a local oscillator for generating modulated signals for wireless data communications. Processor 106 also processes communication data received from transceiver 105 .

Motion Sensing:

Referring to FIG. 3 , in the motion sensing mode of operation, the motion sensing enabled wireless communication system activates the electrical path connecting the first antenna 101 to the coupler 110 and in parallel to the transceiver 105 and then to the processor 106 . The second antenna 102 is connected to the mixer 108 of the motion sensing receiver 107 connected to the coupler 110 and then to the active filter 109 of the motion sensing receiver 107 . Coupler 110 is connected to transceiver 105 and then to processor 106 . The transceiver 105 functions as a transmitter of motion sensing electromagnetic waves, bypassing its internal modulator to generate an unmodulated electromagnetic wave signal at a carrier frequency selected during ambient frequency scanning operation for motion detection. Unmodulated electromagnetic wave signals are transmitted from the first antenna 101 . When the transmitted electromagnetic wave signals are reflected back from the surface of the object, they are received by the second antenna 102 and sent to the motion sensing receiver 107 . Motion sensing receiver 107 includes mixer 108 and active filter 109 . The transmitted electromagnetic wave signal generated by the transceiver 105 is also introduced into the mixer 108 through the coupler 110 . The reflected signal is mixed with the transmitted signal in mixer 108 and then passed through active filter 109 to generate a Doppler signal. Processor 106 analyzes the Doppler signal using short-time Fourier transform or time-domain analysis, where the short-time Fourier transform or time-domain analysis utilizes the desired Doppler signal of 1-25 Hz corresponding to the human motion velocity. Le frequency.

The short-time Fourier transform is a signal processing technique that is often used as the first step in analyzing Doppler signals. The result of the short-time Fourier transform on the Doppler signal is a spectrogram representing the frequency of the reflected RF wave over a short time window. Based on the image of the spectrogram, the presence of human motion can be determined. Details of short-time Fourier transform applications are disclosed in "Application of continuous wave radar for human gait recognition" by Michael, Otero, MITER, the disclosure of which is incorporated herein by reference in its entirety.

Interference detection:

Referring to FIG. 4 , in the jamming detection mode of operation, the wireless communication system with motion sensing function activates the following electrical path: it connects the second antenna 102 to the mixer 108 connected to the coupler 110 of the motion sensing receiver 107 , and then connected to the active filter 109 of the motion sensing receiver 107. Coupler 110 is connected to transceiver 105 and then to processor 106 . Electromagnetic wave signals from the environment are received by the second antenna 102 and then sent to the motion sensing receiver 107 . The transmitted electromagnetic wave signal generated by the transceiver 105 is also introduced into the mixer 108 through the coupler 110 . The ambient signal is mixed with the transmit signal in mixer 108 , passed through active filter 109 , and then analyzed by processor 106 . Since the ambient signals are not reflected signals of the electromagnetic wave signal generated by the transceiver 105, they are noise or interference signals. To avoid false identification of disturbances as human motion, a noise floor is built that encompasses the highest amplitude of the received ambient signal. The noise floor is then factored into the motion detection analysis by processor 105 to eliminate false motion detections.

Fig. 5 has described an embodiment of the wireless communication system with motion sensing function, and this wireless communication system carries out aforementioned four operations continuously within specific system time period (for example frame) , allocates 15ms to environmental frequency scanning, then gives Motion sensing is allocated 800 ms, followed by 400 ms for interference detection, and finally 50 ms for data communication. The cycle begins with an ambient frequency sweep. Selecting the purest channel for the carrier signal for motion detection, the system turns to motion sensing. The system can set an amplitude threshold so that only received signals with amplitudes above the threshold are considered as electromagnetic wave signals reflected back from surfaces of objects detected in the detection area. Once this signal is received and a Doppler signal is generated, the system verifies that the Doppler frequency is within 1-25 Hz to ensure that human motion is detected, otherwise the system continues motion sensing operation. The system can also be configured to check for repetitive motion. In this case, the system continues motion sensing operation even when human motion is detected. Finally, the system detects disturbances to eliminate false motion detections.

Embodiments disclosed herein include processors, which may be implemented by utilizing general or special purpose computing devices, computer processors, or electronic circuits including, but not limited to, digital signal processors (DSPs), application specific integrated circuits (ASICs) ), Field Programmable Gate Arrays (FPGAs), and other programmable logic devices configured or programmed in accordance with the teachings of this disclosure. Based on the teachings of the present disclosure, those skilled in the field of software or electronics can easily construct computer instructions or software codes to run in general-purpose or special-purpose computing devices, computer processors, or programmable logic devices.

The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to those skilled in the art.

The embodiments were chosen and described in order to better explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention through various embodiments with various modifications as are suited to the actual application contemplated. The scope of the invention is to be limited by the appended claims and their equivalents.

Claims (12)

1. A system for sensing motion and performing wireless communication comprising: One or more antennas for transmitting and receiving wireless data communication signals and motion detecting electromagnetic waves; A transceiver having a signal generator and a modulator configured to generate a modulated RF signal for wireless data communication, the transceiver also configured to generate an unmodulated RF carrier signal, the unmodulated The modulated RF carrier signal bypasses the modulator for motion detection; a motion-sensing receiver for receiving motion-detecting electromagnetic waves that have been transmitted by the transceiver, reflected by one or more objects or persons, and received by one or more antennas; one or more electrical switches for switching between activating at least a first electrical path for wireless data communication and activating at least a second electrical path for motion detection, the one or more electrical switches being responsive to a control signal such that A unit period of system operation is divided into at least a portion of time during which the one or more switches are configured for wireless data communication along the first electrical path and another portion of time during which wherein the one or more switches are configured for motion detection along the second electrical path; one or more processors that generate control signals for one or more electrical switches, and process motion-detection electromagnetic wave data from the motion-sensing receivers, and send wireless communication data to and process data from the transceivers Communicates data wirelessly and provides control signals to the transceiver. 2. The system of claim 1, wherein the one or more electrical switches further configure a third electrical pathway for scanning the surrounding environment for available frequencies and selecting the appropriate frequency to generate motion detection electromagnetic waves. 3. The system of claim 1, wherein the motion sensing receiver includes a mixer and a filter. 4. The system according to claim 1, wherein the motion detection electromagnetic wave data from the motion sensing receiver is a Doppler signal generated by a Doppler effect of a moving object reflecting the electromagnetic wave. 5. The system of claim 1, wherein the transceiver includes a single communication port for transmitting and receiving RF signals. 6. The system of claim 1, wherein the transceiver signal generator comprises a local oscillator. 7. The system of claim 2, wherein the one or more processors further control the detection of interfering signals by identifying an ambient noise layer in the detection area. 8. A system for sensing motion and performing wireless communication comprising: One or more antennas for transmitting and receiving wireless data communication signals and motion detecting electromagnetic waves; A transceiver having a signal generator and a modulator configured to generate a modulated RF signal for wireless data communication, the transceiver also configured to generate an unmodulated RF carrier signal, the unmodulated The modulated RF carrier signal bypasses the modulator for the motion detection electromagnetic wave signal; a motion-sensing receiver for receiving motion-detecting electromagnetic waves that have been transmitted by the transceiver, reflected by one or more objects or persons, and received by one or more antennas; one or more electrical switches for switching between activating at least a first electrical path for wireless data communication and activating at least a second electrical path for motion detection, the one or more electrical switches being responsive to a control signal such that A unit period of system operation is divided into at least a portion of time during which the one or more switches are configured for wireless data communication along the first electrical path and another portion of time during which wherein the one or more switches are configured for motion detection along the second electrical path; one or more processors that process motion detection electromagnetic wave data, transmit wireless communication data to and process wireless communication data from the transceiver, provide control signals to one or more electrical switches, and provide control signals to the transceiver ; Wherein, the system is configured to participate in a wireless network to communicate with one or more electrical appliances or devices having a wireless communication function, so that when the system detects motion, the system transmits wireless data to the one or more electrical appliances or devices, to control the operation of one or more electrical appliances or devices. 9. A method for sensing motion and performing wireless communication comprising: Transmitting and receiving wireless data communication signals and motion detection electromagnetic waves through one or more antennas; Through a transceiver having a signal generator and a modulator, a modulated RF signal for wireless data communication is generated, and an unmodulated RF carrier signal is generated that bypasses the modulator for motion detection ; Using a motion sensing receiver, sensing received motion detecting electromagnetic waves that have been transmitted by the transceiver, reflected by one or more objects or persons, and received by one or more antennas; Activating at least a first electrical path for wireless data communication and activating at least a second electrical path for motion detection are configured using one or more configurable switches responsive to a control signal to enable the system The unit period of operation is divided into at least a portion of time during which the one or more switches are configured for wireless data communication along the first electrical path and another portion of time during which , one or more switches configured for motion detection along the second electrical path; Through one or more processors, the motion detection electromagnetic wave data received by the motion sensing receiver is processed, the wireless communication data is sent to the transceiver and the wireless communication data is processed from the transceiver, and the control signal is sent to one or more electronic devices. switch and send to the transceiver. 10. The method according to claim 9, wherein the motion detection electromagnetic wave data from the motion sensing receiver is a Doppler signal generated by a Doppler effect of a moving object reflecting the electromagnetic wave. 11. The method of claim 9, further comprising scanning the surrounding environment for available frequencies and selecting an appropriate frequency to generate the motion detection electromagnetic waves. 12. The method of claim 11, wherein the one or more processors further control the detection of interfering signals by identifying an ambient noise layer in the detection area.

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