COMMUNICATION METHOD AND SYSTEM FOR ELECTRONIC DEVICES - Patent application

Abstract

The present invention relates to a method and a corresponding system for establishing communication between two electronic devices, the method comprising: transmitting, from a first of the devices, a first acoustic signal within a predetermined frequency range for at least one predetermined time period, the acoustic signal including a recognizable code, the code including connection information; receiving an acoustic signal at a second of the devices and analyzing the code, the analysis including recognizing at least one predetermined time period; and transmitting a second signal to establish communication with the first device based on the code.

Description

[Technical Field]

[0001] The present invention relates to a method and system for providing communication between electronic devices. In particular, the communication involves the use of acoustic signals to establish communication between two or more nearby electronic devices. This includes electronic devices that can use time-modulated or other coded acoustic signals to transmit acoustic messages (e.g., protocol messages or coded messages) having limited information, e.g., an encoded version of at least one of the device's own network address, to enable nearby electronic devices to connect to the sending electronic device. [Background technology]

[0002] Many electronic devices, such as mobile phones and laptops, include acoustic transducers capable of transmitting and receiving acoustic signals. The acoustic signals may be in the infrasonic range, the audible frequency range, or the ultrasonic range. If the acoustic signal is in the audible frequency range, the acoustic message will be audible to humans unless the frequency used by the acoustic message and its amplitude can be hidden in another audible signal (e.g., a notification sound from the transmitting device, music playback, a voice command, etc.) transmitted by either the electronic device in question or a nearby electronic device that masks the audible acoustic message. U.S. Patent Application Publication No. 2021 / 0037210 describes a system in which a device transmits an ultrasonic signal, which is received by a receiving device, and the address of the transmitting device is extracted, which can be used to provide a WiFi connection or the like between the two devices. US Patent Application Publication No. 2012 / 0214416 describes devices capable of establishing communication, where one of the devices sends an invitation signal within the transmitted acoustic signal and the other device is configured to accept the invitation and allow the connection; a similar solution is also disclosed in US Patent Application No. 2020 / 314654.

[0003] In US Patent Application Publication No. 2019 / 0394567, a solution uses acoustic signals to analyze the surroundings, which may include a code. The transmitted code is used to analyze the surroundings, and any communication with other units in the surroundings is performed by transmitting packets using wireless transmissions using electronic communication protocols. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2021 / 0037210 [Patent Document 2] U.S. Patent Application Publication No. 2012 / 0214416 [Patent Document 3] U.S. Patent Application Publication No. 2020 / 314654 [Patent Document 4] U.S. Patent Application Publication No. 2019 / 0394567 Summary of the Invention [Means for solving the problem]

[0005] One problem associated with the prior art is that transmitting acoustic messages incurs some power consumption. While the systems discussed in U.S. Patent Application Publication No. 2021 / 0037210 are stationary and typically connected to a power source, many devices rely on limited battery capacity, and therefore an object of the present invention is to reduce the power consumption of the system and devices therein. Another problem is that continuous signal transmission increases the general noise level and interference in an environment containing several devices attempting to communicate acoustic messages and / or representing other systems using the same acoustic frequency range. An object of the present invention is to provide a solution, including a method and system, that aims to solve these problems. This is achieved as set forth in the accompanying claims.

[0006] The invention therefore relates to a communication established based on a first acoustic signal comprising a recognizable code over a period of time, and a second device receiving the acoustic signal with the code, analyzing the acoustic signal and the time period and using the code to establish communication with the first device. Thus, the first device has an acoustic transmitter (such as a speaker) and the second device has a receiver (such as a microphone).

[0007] The present invention can be used to encode data using time modulation on a single acoustic signal (e.g., a sine wave signal) or multiple acoustic signals (e.g., multiple sine waves with different frequencies designated F1, F2, F3, etc.) and transmit that data in an acoustic message to other nearby electronic devices.

[0008] Several embodiments of the present invention may be considered. In some cases, the acoustic message contains information that enables the receiving electronic device to connect to the sending electronic device using a preferred communication network (e.g., Bluetooth, Wi-Fi, 5G, etc.). The transmitted signal may also contain additional information about the electronic device beyond its network address or the services it offers. The additional information may include the SSID of the wireless network to which the sending electronic device is connected and a monotonically increasing sequence number or timestamp to ensure that consecutive acoustic messages are different. A forward error correction scheme (e.g., Reed-Solomon FEC) may also be used to enable correction of errors in the reception process in the second device. One example is a protocol message embedded in the acoustic message that includes a challenge, network type, protocol, and corresponding port number to be used to connect to the sending electronic device. In some embodiments, the transmitted signal may also include the network address of another electronic device, which may or may not have the capability to transmit the acoustic signal itself. In some embodiments, the transmitted signal may include multiple network addresses and supplemental information about the electronic device. The transmitted signal may, in some embodiments, include a network address and supplemental information for a set of electronic devices identified by that network address.

[0009] The basic principle of the present invention is that an acoustic signal only needs to be transmitted from a first electronic device for a specific time period (e.g., a time-modulated or coded signal) or repeatedly transmitted at a specific rate (e.g., 2 Hz) to allow a second electronic device with an acoustic receiver to receive the signal and, through software or hardware processing, demodulate or decode the received signal to detect the transmitted signal. Since the demodulating second device can detect the exact transmission period of the acoustic signal transmitted by the first device, the first and second devices can exchange information by sending a set of consecutive acoustic signals, the information being encoded using the time period of the transmitted acoustic signal. The first device can increase its data rate by transmitting data in parallel with transmitting information simultaneously at multiple acoustic frequencies using unique time periods.

[0010] If a first device transmits a signal coded using one or more sine waves or sine wave pulses (e.g., 100-200 ms), the second device can decode the signal by extracting the sine waves or sine wave pulses using a deep neural network trained for signal processing or decoding. The number of unique codes depends on the number of different sine wave frequencies available for coded communication between devices in the coded message and the number of sine wave pulse frequencies used by the first device. In the case where 20 different sine wave frequencies are available and the first device uses three different sine wave pulses in each message, the number of unique sine wave pulse triplets is 1140. When using multiple sine waves, the separation of the sine waves may need to take into account the Doppler effect, as described, for example, in NO20221244; otherwise, the separation should be at least 150-200 Hz when the user is walking.

[0011] The specific time period used to modulate the device may be defined as a period during which the signal exceeds a limit at one set of frequencies that can be detected by a distant second device. The signal may be repeated or continued at a lower volume and / or alternative frequency. Furthermore, the second device may adjust its sensitivity or frequency depending on the reception, searching for signals at other frequencies and amplitudes.

[0012] The invention will now be described in more detail with reference to the accompanying drawings, which illustrate the invention by way of example. [Brief explanation of the drawings]

[0013] [Figure 1] 1 illustrates a system according to the present invention, including a first and a second device. [Figure 2] FIG. 1 illustrates a process according to a first embodiment of the present invention. [Figure 3] FIG. 10 illustrates a transmitted signal according to another embodiment of the present invention using multiple frequencies. [Figure 4] FIG. 10 illustrates a transmitted signal according to yet another embodiment of the present invention using variable amplitude to distinguish signal durations. [Figure 5] FIG. 2 illustrates a time sequence of a transmitted signal in the time domain. [Figure 6] FIG. 1 illustrates compensation for variable signal strength. [Figure 7] FIG. 6 shows a time sequence of signals according to FIG. 5; [Figure 8] FIG. 1 illustrates the use of several frequencies. [Figure 9] FIG. 1 illustrates the use of several frequencies. DETAILED DESCRIPTION OF THE INVENTION

[0014] 1, the present invention involves at least one first device 1 and a second device 2. The first device 1 includes a first processor 3 that generates a signal to be transmitted to a speaker or similar transducer 4 capable of transmitting an acoustic signal within a selected frequency range and thus behaving like an acoustic message, the acoustic signal including a recognizable code or protocol message. As discussed below, the acoustic message directly or indirectly includes information for obtaining wireless communications, including, for example, an Internet Protocol / IP address for a WiFi connection.

[0015] The second device 2 includes a microphone 5 or similar transducer capable of receiving signals within a selected acoustic frequency range and transmitting the received signals to a second processor 6. The second processor 6 is configured to analyze the received signals to find a code and, if applicable, forward the code to a communication unit 7, which is configured to transmit a WiFi signal requesting access to the address of the first device. Alternatively, the second device may request further information about the device through a lookup service using data communication (e.g., WiFi) or a local lookup from an updated device information database in the second device. The device information lookup may provide the information necessary for the second device to initiate data communication (e.g., WiFi, Bluetooth) with the first device, or with another device if the first device is acting as a proxy for the device with which the second device needs to communicate. WiFi communication may be initiated when the signal is received in the WiFi unit of the first device.

[0016] Alternatively, the second device may respond by generating and transmitting an acoustic response signal 10 through a speaker in the second device, which may be received by the first device at 12, analyzed at 13, and, if applicable, provide extracted information to the first processor 3. This may be the case when the first device requests the second device's IP address and the second device responds by transmitting its address using an acoustic signal. This may be necessary if the coded signal from the first device is not unique, preventing the first device from being uniquely identified by the transmitted code. In that case, the second device may initiate an acoustic handshake with the first device using another predefined, pseudo-randomly generated coded or modulated signal known to the intended first device and the corresponding second device. These handshake messages may use the same or a different frequency range as previous messages between the devices. Although the encoded message may require a prolonged handshake process to identify the first device, the number of duplicate first devices is immediately reduced by using this acoustic handshake process.

[0017] Yet another alternative is for the second device 2 to transmit a request signal, either acoustically or using wireless communication, to activate the first device to transmit the modulated or coded message.

[0018] In use, the first and second devices may not be the only ones in the vicinity. The area may include several first devices and other devices that can be selected by a user interface, and users of different devices may be allowed to initiate by choosing the device with the highest amplitude or by connecting to a device that is recognized by the first or second device, for example when a communicated code is stored in the device. The user may select a particular audio message or first device, or the audio message may be set to give priority to some devices.

[0019] The present invention is particularly directed to an acoustic message signal being transmitted from a first device that includes a code for establishing device communication using wireless communication such as WiFi or Bluetooth.

[0020] Sound messages can be sent continuously or as time-separated messages at a fixed or variable message rate within a specific time period (e.g., "use a 2 Hz message rate, send a new message every 500 ms"). If sound messages are sent continuously, the beginning of the sound message needs to be identifiable. Sound messages may also include random shifts based on a pseudorandom number generator with a known seed known to both devices (e.g., up to 30% of the time between two sound messages, given a predefined rate). One option is to begin the sound message with a time-modulated time period that is identifiably larger than the largest number to be encoded. Another option is to change the amplitude value of the sine wave to a third level that is lower than the time-modulated time period but significantly different from the amplitude level during the time-modulated time period. A third option is to include a fixed preamble or flag, such as those used for link layer protocols such as HDLC (i.e., a flag sequence field). A fourth option would be to change the frequency, phase, amplitude level, or any combination of these changes in a identifiable pattern that can be detected by the second device using either signal processing or a neural network engine trained to detect patterns transmitted by the first device.

[0021] In some scenarios, the first device does not send any unsolicited acoustic messages to save power and avoid sending acoustic signals unnecessarily. In these scenarios, any second device that enters the first device's space should instead send its own acoustic request message to the first device to request an acoustic message with the necessary information. Once the first device receives, processes, decodes, and interprets the request, the first device begins sending acoustic messages at a high message rate. The first device may use a backoff mechanism where the message rate is reduced until a minimum message rate is reached. Once the second device extracts the information in the acoustic message, it can send a message to the first device over the communication network to inform the first device that the acoustic message was successfully received. The message from the second device may include data indicating to the first device that transmission of the acoustic message is no longer required or that the acoustic message should be sent X more times, where X is a predefined configuration value or is included in the message from the second device.

[0022] The first device or any other motion-detecting device in the space may use motion detection, such as an inertial measurement unit, to trigger distance measurement or estimation to the nearest user in the space and use that information to determine when to send an acoustic message. Distance measurement may be performed using an acoustic signal, as discussed in NO20221247, without adding additional coding to the signal. Other activity measurements may be used as triggers, such as a touchscreen / sensor, a light sensor, or a recognition sound. The first device may begin sending an acoustic message when motion or activity is detected within the space or room in which the first device is located, as discussed in NO20221246, in which propagation time and phase shifts may be used to detect the relative distance between two devices using an acoustic signal that includes at least one acoustic transducer on one device and at least one transducer on the second device. When the direction is measured, one of the devices has two transducers that receive or transmit the acoustic signal. The transmission of the acoustic message may be stopped when the motion detector no longer detects any motion. The acoustic message may also be stopped if the distance exceeds a certain limit.

[0023] In some embodiments, multiple second devices may be allowed to communicate with the first device. In these situations, the first device should continue to send sound messages for a preconfigured period of time, based either on the number of messages or on absolute time. In some cases, the first device may use a backoff mechanism where the time between sound messages is doubled until a maximum value is reached. The first device may be configured to continue sending sound messages at this message rate to ensure that later devices can still receive the sound messages. An alternative is for the newly arrived second device to send a sound message itself requesting that the first device begin a new sequence of sound message transmissions.

[0024] While processing the acoustic message, the second device may measure the SNR and possibly amplitude value of the acoustic signal and include this information in a message sent over the communication network to the first device or a proxy-type device. According to one embodiment, the first device may use these values ​​to modify either a characteristic such as the amplitude or frequency of the acoustic signal or the transmission unit used for time modulation.

[0025] In one embodiment of the present invention, shown in FIG. 2, a first device transmits an encoding of its IPv4 network address using a single acoustic frequency. In this example, the first device's network address is 192.168.86.2. In FIG. 2, the first device sends a sinusoidal signal with four distinct time periods, with the amplitude within a predefined range for 192 samples during the first distinct time period. In the second, third, and fourth distinct time periods, the signal is within the allowable amplitude range for 168, 86, and 2 samples. In some scenarios, the second device will be unable to detect the number of samples during the time period to within a single sample. In situations where the second device does not have the resolution to detect the time period to within a single sample for various reasons, the first device can extend the transmission period to identify the number M by transmitting a signal for N*(M+1) samples, where N is the size of the transmission unit. The reason for adding one transmission unit as an offset (i.e., M+1) is to be able to encode the number 0. If M is 0, the distinguishable time period is N samples. If M is 1, the distinguishable time period is N*2 samples. The second device must take the zero offset into account when calculating the number M from the measured time period of the received signal. If the transmission unit is 2, the IP address will be transmitted during distinguishable time periods of 386, 338, 174, and 6 samples. The second device detects the distinguishable time period, divides the detected time period by the transmission unit (i.e., N=2), and subtracts the zero offset (i.e., N=2) to arrive at the IP address 192.168.86.2. With N=1, the detection period for an IP address using a single sine wave frequency as described above is 193 + 169 + 87 + 3 = 452 samples. At 48 kHz, the detection period with N=1 is approximately 10 milliseconds.

[0026] In another embodiment of the invention, a first device transmits its IP address using four simultaneous sine wave signals, combining time modulation with the use of multiple frequencies. The sine wave frequencies must be spaced far enough apart in frequency (Hz) that the second device receives data from each of them at exactly the same time. The sine wave frequencies typically must be spaced 100-300 Hz apart to handle the Doppler effect of a walking user.

[0027] If the second device has sensors (e.g., gyroscopes and accelerometers, Hall-effect sensors, or other sensors that provide rotational or linear velocity) that can be used to measure the second device's movement in any direction along the line between the first and second devices, the second device can adjust to any Doppler shift in the frequency transmitted by the first device, for example, as described in NO20221244. Another option is for the second device to ignore the acoustic message if the motion sensor indicates that the second device is moving more than a predefined amount. If so, the second device waits until it no longer encounters any problems related to the Doppler shift in frequency. Using a transmission unit of N, the IP address 192.168.86.2 is transmitted using four different sinusoidal frequencies with time periods of N*(192+1), N*(168+1), N*(86+1), and N*(2+1) samples, respectively. As mentioned above, the detection period for an IP address using four simultaneous sine wave frequencies is the time period of the largest number transmitted. In this example, the detection period is the transmission time of the largest number N*(192+1)=N*193 samples. At 48 kHz, the detection period is approximately N*4 milliseconds.

[0028] In one embodiment of the present invention, a first device transmits an encoded version of its IPv4 network address using a single acoustic frequency. In this example, the first device's network address is 192.168.86.2, which is 0xC0-0xA8-0x56-0x02 in hexadecimal. If the first device transmits a sinusoidal signal with eight distinct time periods, each time-modulated time period corresponds to a nibble in the hexadecimal representation of the IPv4 network address. For a time-modulated time period of 0xC, N*(0xC+1)=N*13. The remaining time-modulated time periods are N*1, N*11, N*9, N*6, N*7, N*1, and N*3. In total, the detection period is N*38 samples.

[0029] Although the most common data unit in most embodiments is a 4-bit nibble, the first device may partition the acoustic message into a series of bits and transmit the acoustic message using just two different time-modulated time periods corresponding to the values ​​0 and 1.

[0030] The first device may listen for other sources transmitting on at least one overlapping or interfering frequency used by the first device. If so, the first device may delay transmission until the other sources stop transmitting. If the other sources continue to transmit interfering acoustic signals, the first device may change the frequency of the sine wave or waves encountering the unwanted interference to eliminate or reduce the effect of the interference from the other transmitting sources. The concept of frequency hopping to avoid interference is described in more detail in Norwegian Patent Application No. NO 20220394. Because the first device may change one or more of the frequencies used for time modulation, the second device must be prepared to handle receiving an unknown or predefined set of frequencies. Detecting multiple frequencies is possible with FFT processing. To ensure that a specific frequency is used for the acoustic message, the message should include the preamble described above to clarify that this is the beginning of the acoustic message. Because the first device may use multiple frequencies to transmit the sound message, all or some of which may be transmitted on non-standard frequencies, the frequency number (e.g., F1, F2, F3, F4, etc.) required to ensure correct decoding of the sound message must be included in the sound message.

[0031] In another embodiment of the present invention, shown in FIG. 3, a first device may encode data using time modulation in combination with the use of multiple frequencies, designated f1, f2, f3, and f4, and transmit the data in an acoustic message to another nearby electronic device. It may be possible to transmit a 16-byte IPv6 address using 16 simultaneous sine wave signals. The sine wave frequencies must be sufficiently spaced in frequency (Hz) so that a second device can receive data from each of them at exactly the same time. As described above, the detection period for an IPv6 address using 16 simultaneous sine wave frequencies is the time period of the largest number transmitted. In this example, the detection period is the transmission time of the largest number of samples, N*(255+1)=N*256. At 48 kHz, the maximum detection period is approximately N*5.4 milliseconds.

[0032] In another embodiment of the present invention, the first device uses various amplitude levels to shorten the detection period, as shown in FIG. 4. When transmitting an IP address (e.g., 192.168.86.2), the first device varies the amplitude to encode the IP address. The first device increases the amplitude level until the amplitude of the sinusoidal signal is within the acceptable range and transmits the sinusoidal signal for a time period corresponding to the first byte of the IP address (i.e., N*(192+1) samples), then reduces the amplitude until it is below the acceptable range, or preferably to zero amplitude, and holds it there for a time period corresponding to the second byte of the IP address (i.e., N*(168+1) samples). The amplitude is again increased until it is within the acceptable range and holds it there for a time period corresponding to the third byte of the IP address (i.e., N*(86+1) samples), then reduces the amplitude to below the acceptable range and holds it there for a time period corresponding to the fourth byte of the IP address (i.e., N*(2+1) samples). By using the length of the time period, intermediate time periods where the amplitude is below the acceptable range can reduce the overall detection time.

[0033] The first device transmits an acoustic message within a frequency range compatible with a preconfigured sampling rate appropriate for the output of the first device's audio system and the input of the second device, which receives and samples the received signal. Some platforms support only a 48 kHz sampling rate for input and output, while other platforms support higher sampling rates, such as 96 kHz, 192 kHz, 384 kHz, etc. If the time modulation uses a specific number of samples as the transmission unit rather than absolute time in microseconds, the first and second devices must agree on both the frequency and sampling rate to be used. Based on the frequency used by the first and second devices, to limit the power consumption of one or both devices, the first and second devices should select the lowest sampling rate from a set of preconfigured sampling rates that still allows the use of a transmission frequency according to the Nyquist sampling theorem; for example, a frequency of 25 kHz requires the lowest sampling rate above 2 * 25 kHz = 50 kHz. If an acoustic message is sent using time modulation at a sinusoidal frequency of 25 kHz, a sampling rate above 50 kHz is required. If an acoustic message is sent from a first device with time modulation at a frequency of 22.5 kHz, the sampling rate must be greater than 2*22.5 kHz = 45 kHz. The first and second devices may need to be pre-configured with the time-modulated frequency that should be used to correctly send and receive the acoustic message.

[0034] In some embodiments, the second device may include at least one acoustic transmitter capable of transmitting an acoustic message back to the first device using time modulation on the same or a separate frequency set. The message may be interpreted as an acknowledgment of receipt of the acoustic message sent by the first device. The acknowledgment may also include a hash or CRC of the acoustic message sent by the first device. If the acoustic message from the first device includes a timestamp or monotonically increasing sequence number, the first device may filter out acknowledgments from the second device that are too old or outside the acceptable window for the timestamp or sequence number.

[0035] In some embodiments, the second device may send a time-modulated acoustic message asking the first device to increase its transmission unit if the time-modulated message is not discernible with the current signal-to-noise ratio. This may be necessary in situations with interference from other sources or reverberation effects from the time-modulated signal itself.

[0036] There are other modulation techniques that are more efficient and can increase the bit rate of acoustic communication. However, time modulation is a simple technique that can be implemented in small electronic devices with limited processing power. While it is not ideal for transferring large amounts of data, it is sufficient for short messages (e.g., messages) between electronic devices.

[0037] The amplitude level of the acoustic message should preferably be adjusted to suit the space into which the acoustic message is being transmitted. This may be a configurable option based on the size of the space or portion of the space that can be used as needed by the receiver of the acoustic message. A calibration process can also be used, in which a first device transmits a continuous signal at a specific amplitude level and a predefined frequency, and a second device, in this case used for calibration, is moved to the far end of the space to provide feedback on the amplitude. The second device accepts the specific amplitude level by sending a message to the first device using the communication network. If the second device can reliably detect the signal at the current amplitude, the first device may reduce the amplitude, and the experiment can be repeated. This iterative process of trying specific amplitude levels can continue until the amplitude level is at the minimum acceptable amplitude level for the second device at the far end of the space. The calibration process can also be used to select the frequency used by the first device to avoid influences from other sources or reverberation effects from large reflectors or surfaces.

[0038] Another challenge with the time modulation scheme discussed here is the effect that reflections from various surfaces can have on the transmission period and how large the transmission unit needs to be to correctly identify the transmission period. The transmission unit can also be selected during a calibration process when the first device is installed. During this calibration process, the first device can send a known time-modulated sequence of numbers using a specific transmission unit. The transmission unit can also be increased by changing the configuration or setup of the first device, either automatically or manually by an IT supervisor. The transmission unit should be increased from N=1 up to a value of N that allows the second device to reliably identify the number sequence. The number sequence should include neighboring numbers, etc., to make it easier for the second device to determine whether the transmission unit is acceptable. Because the calibration process should be performed after the first device is installed, the selection of the transmission unit takes into account the actual space in which the first device operates when determining the transmission unit. If the first device is moved elsewhere (e.g., to a mobile device), the calibration process may have to be repeated. The calibration process may be repeated if at a later stage the second device detects that it did not successfully decode the acoustic message from the first device (e.g., an incorrect value in the acoustic message).

[0039] Each time-modulated time period must have both a beginning and an end. For amplitude-based acoustic signals, as shown in FIG. 5, an alternative is a sudden increase or decrease in amplitude to signal the beginning and end of the time-modulated time period, respectively. The amplitude increase (i.e., the beginning of the time period) may be an upward ramp of the signal from a significant lower amplitude level (e.g., 0 amplitude) until a selected amplitude level is reached. The amplitude decrease (i.e., the end of the time period) may be a downward ramp of the signal to a significant lower amplitude level (e.g., 0 amplitude) until a lower amplitude level is reached. The upward and downward ramp periods should be as short and steep as possible to avoid audible effects (e.g., popping noise) from the acoustic output device. The lower amplitude level and the upward / downward ramp periods may also be included in the calibration process for selecting transmission units, discussed above, to ensure that the beginnings and ends of these time periods are part of the transmission unit selection. It is possible to use a higher amplitude in the middle of the time-modulated time period, but this increases power consumption and makes it harder to distinguish between the time-modulated signal from the direct path between the first and second devices and reverberations bouncing off other objects and surfaces in space. There are other ways to identify the beginning and end of a time-modulated time period, such as pulses of separate but different frequencies, signal phase shifts, etc., but changing the amplitude is by far the simplest.

[0040] The amplitude level can be important in some cases. Figure 6 shows that the amplitude level can change by several dB when people are moving around in a space. This means that the difference between the allowable amplitude level of the time-modulated time periods and the lower level in the middle of these periods needs to be higher than the change caused by people moving around in the space. It is also possible to frequently send an additional amplitude detection sine wave at a frequency close to the frequency used for time modulation. This amplitude detection sine wave is transmitted at the same amplitude as the time-modulated one. If the amplitudes of both sine wave signals are changed equally up or down at the same time, this is caused by a wall being removed or people or objects moving around in the space. If only the time-modulated frequency is changing its amplitude, this is done by the first device as part of the time modulation scheme to start or end a time period. If the first device is using time modulation of multiple frequencies to transmit an acoustic message at a higher bandwidth, the first device can also, in many situations, compare the amplitude changes in all of the sinusoidal signals to determine whether the amplitude changes were accidental or intentionally made by the time modulation first device. Furthermore, even if the first device is transmitting at multiple frequencies, separate amplitude control signals may be easier.

[0041] In one embodiment of the present invention, the second device may not be able to receive the acoustic message within the ultrasonic range. If the second device can receive the acoustic message within the audible range, the first device may use a lower sampling rate that, due to aliasing, will mirror the transmitted frequency around the sampling rate of the second device. If the time-modulated time period is based on actual time or the transmission unit of the sampling rate used by the first device is known, the second device can calculate the absolute time of the transmission unit. Using this information, the second device can extract the acoustic message by receiving and processing the aliased frequency transmitted by the first device. If this aliasing causes further problems with the correct interpretation of the time-modulated time period, a forward error correction scheme may be used when creating the acoustic message.

[0042] The first device may be a wifi hotspot, a video conferencing system and a controllable light source, a speaker system, etc. Any electronic device that provides information to other devices allows the other devices to connect to a particular service, electronic device or network.

[0043] If the network address extracted by the second device from the acoustic message is not the correct address or the second device cannot connect to the device due to network problems, the second device can try all of the other network addresses in the acoustic message, one by one, until it finds one that works. If the acoustic message did not include any optional network addresses, the second device can send an acoustic message to the first device. The second device should listen for other acoustic sources in the environment and, if necessary due to interference problems, delay transmission or possibly change the frequency or set of frequencies before sending the acoustic message to the first device or the device with which the second device should communicate. If the acoustic message includes an error message, the error message should indicate what the problem is, and the second device can then request an alternative network address from the first device, which will be sent in a new acoustic message from the first device. If none of the alternative network addresses work, the second device should send an acoustic message indicating that the communication channel is broken.

[0044] If neither the first nor the second device contains any network interface connected to the logically shared communications network, or if none of the advertised communications channels are working for unknown reasons, the only viable option for the devices is to communicate using acoustic messaging based on some kind of modulation technique, which may be time modulation.

[0045] In one embodiment of the present invention, the first device is a lighting fixture that can be controlled by a smartphone app. When the smartphone app receives an audio message with information about the lighting fixture, the app can connect to the lighting fixture's control unit and take over control of the specific lighting fixture based on the lighting fixture's ID embedded in the audio message. If there are multiple lighting fixtures, the smartphone app can use positioning as described in U.S. Patent Application Publication No. 2017 / 0083285 or WO2020 / 046137 to select the lighting fixture to control. This can be done even if there are multiple lighting fixtures in the same space, as long as the lighting fixtures are transmitting audio messages one after the other. The smartphone app can align a line passing through at least two of its audio receivers perpendicular to the direction of the lighting fixture to be controlled. When a second device, also pointing to a smartphone, receives an audio message belonging to the first device, the second device can use the information in the audio message to connect to the control unit and assume control of the lighting fixture.

[0046] In another embodiment of the present invention, the first device is a monitoring device that tracks whether a second device is still nearby. The first device can monitor multiple second devices if they can be identified by their unique time-modulated or coded acoustic messages. These second devices can use either time-division multiplexing or frequency multiplexing to prevent their acoustic messages from interfering with each other. If any of the acoustic messages monitored by the first device disappears, it means that the corresponding second device has stopped working or the first device has been removed from a space or room. The first device may also be a security device that can sound an alarm or send an alarm message to indicate that a particular device is no longer working properly, has been removed, or has been stolen.

[0047] Figures 8 and 9 illustrate the use of several frequencies. In Figure 8, a signal 22 is transmitted that includes three different frequency bands. The receiver can detect the signal and its corresponding signal duration to analyze and detect the transmitted code. In Figure 9, there are three different signals, each containing three different frequencies. As mentioned above, there are 20 different sinusoidal frequencies available, and the first device uses three different sinusoidal pulses in each message, so the number of unique sinusoidal pulse triplets is 1140. This improves the receiver's ability to distinguish between different signal sources.

[0048] In summary, the present invention relates to a method and system for establishing communication between two electronic devices over a wireless communication system, each of the devices also including an acoustic transducer. The method comprises: transmitting, from a first one of the devices, a first acoustic signal within a predetermined frequency range for at least one predetermined time period, the acoustic signal including a code recognizable to a second device, the code including information for enabling a connection between the devices; receiving an acoustic signal at a second of the devices and analyzing the code, the analysis including recognizing at least one predetermined time period; transmitting a second signal from a second device that has established communication with the first device based on the code; Includes.

[0049] The transmitted acoustic signal may be composed of a plurality of acoustic frequencies, the code comprising information in at least two of the acoustic frequencies, or alternatively the code is comprised in a sequence of acoustic signals within said time period.

[0050] The second signal may be an acoustic or electromagnetic communication system, and the communication when established may be within electromagnetic range, and the transmitted code includes an IP address or similar for connecting to the first device.

[0051] The transmission of the first acoustic signal may be initiated by motion detected in the vicinity of the first device, for example, using a motion sensor in one of the devices or an external sensor. The transmission of the first acoustic signal is initiated upon receipt of a request signal from the second device.

[0052] The present invention also relates to a communication system including at least two electronic devices. As described above, a first device is configured to transmit a first acoustic signal within a predetermined frequency range for at least one predetermined time period, the acoustic signal including a recognizable code, the code including connection information enabling communication between the devices. A second device is configured to receive and analyze the transmitted signal, the analysis including detecting at least one predetermined time period, and upon detecting the code, transmit a second signal to establish communication with the first device.

[0053] As mentioned above, the transmitted acoustic signal is made up of a plurality of acoustic frequencies and the code contains information in at least two of the acoustic frequencies, or alternatively, the code is contained in the sequence of the acoustic signal within said time period.

[0054] A device in the system may include both an acoustic transmitter and a receiver, thus enabling communication by acoustic signals within a particular frequency range, preferably outside the audible range, preferably within the ultrasonic range, and therefore the second signal may also be an acoustic signal.

[0055] The second signal is an electromagnetic communication signal, particularly when the established communication is within electromagnetic range. The transmitted code includes an IP address or similar that allows the second device to connect to the first device through an IP network. [Explanation of symbols]

[0056] 1. First Device 2 Second Device 3 First Processor 4 transducers 5 Microphone 6 Second Processor 7. Communication Unit

Claims

1. 1. A method for establishing communication between two electronic devices, comprising: transmitting, from a first one of the devices, a first acoustic signal within a predetermined frequency range for at least one predetermined time period, the acoustic signal including a recognizable code, the code including connection information; receiving the acoustic signal at a second one of the devices and analyzing the code, the analysis including recognizing the at least one predetermined time period; transmitting a second signal to establish communication with the first device based on the code; A method comprising:

2. The method of claim 1 , wherein the transmitted acoustic signal is comprised of a plurality of acoustic frequencies, and the code contains information in at least two of the acoustic frequencies.

3. The method of claim 1 , wherein the code is included in a sequence of acoustic signals within the time period.

4. The method of claim 1 , wherein the second signal is an acoustic signal.

5. The method of claim 1 , wherein the second signal is an electromagnetic communication signal and the established communication is within an electromagnetic range.

6. The method of claim 5 , wherein the transmitted code includes an IP address or the like for connecting to the first device.

7. The method of claim 1 , wherein the transmission of the first acoustic signal is initiated by motion detected in the vicinity of the first device.

8. The method of claim 1 , wherein the transmitting of the first acoustic signal is initiated upon receipt of a request signal from the second device.

9. 1. A communication system including at least two electronic devices, wherein a first device is configured to transmit a first acoustic signal within a predetermined frequency range for at least one predetermined time period, the acoustic signal including a recognizable code, the code including connection information, and a second device is configured to receive and analyze the transmitted signal, the analysis including detection of at least one predetermined time period, and upon detection of the code, transmit a second signal to establish communication with the first device.

10. 10. The system of claim 9, wherein the transmitted acoustic signal is comprised of a plurality of acoustic frequencies, and the code contains information in at least two of the acoustic frequencies.

11. The system of claim 9 , wherein the code is included in a sequence of acoustic signals within the time period.

12. The system of claim 9 , wherein the second signal is an acoustic signal.

13. 10. The system of claim 9, wherein the second signal is an electromagnetic communication signal and the established communication is within an electromagnetic range.

14. The system of claim 13 , wherein the transmitted code includes an IP address or the like for connecting to the first device.

15. 10. The system of claim 9, wherein the transmission of the first acoustic signal is initiated by motion detected in the vicinity of the first device.

16. The system of claim 9 , wherein the transmission of the first acoustic signal is initiated upon receipt of a request signal from the second device.

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