Methods and apparatus for low audio fallback from remote devices using associated device speaker

Methods and apparatus for configuring a portable communication device are disclosed. The methods include receiving an incoming audio signal, adjusting the incoming signal audio level based on a volume control setting, generating an ultrasonic audio signal having an audio level independent of the volume control setting, mixing the incoming signal with the ultrasonic signal to generate a mixed audio signal, outputting the mixed signal to a remote audio device, receiving a remote audio signal from the remote device, and comparing the remote signal audio level to one or more thresholds to determine whether to output a compensated audio signal to a speaker. The remote signal may be detected by the remote device in response to sound output from the remote device based on the mixed signal, and the compensated signal audio signal may be adjusted based on an estimated loss in loudness associated with the remote signal audio level.

BACKGROUND OF THE INVENTION

Feature rich electronic devices, including portable communication devices, have evolved from simple analog devices to multifunction computing systems with different devices that may each have a speaker and a microphone. The system may include a portable communication device and a remote device. During a communication, the speaker of a remote device typically is configured as the speaker of the system for playing audio output and the microphone of the remote device typically is configured as the microphone of the system for capturing audio input.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein are systems, methods, apparatus, and non-transitory, computer-readable storage media for configuring a portable communication device for low audio fallback.

In one embodiment, a disclosed portable communication device may include an audio communication interface configured to send and receive audio with a remote audio device, a speaker configured to output sound, and a processor. The processor may be configured to receive an incoming audio signal, adjust an audio level of the incoming audio signal that is received based on a setting of a volume control, mix the incoming audio signal having the adjusted audio level with an ultrasonic audio signal to generate a mixed audio signal, output the mixed audio signal to the remote audio device using the audio communication interface, receive a remote audio signal from the remote audio device using the audio communication interface, and compare an audio level of the remote audio signal to one or more thresholds to determine whether to output a compensated audio signal to the speaker. The ultrasonic audio signal may have an audio level independent of the setting of the volume control. The remote audio signal may be detected by the remote audio device in response to sound output from the remote audio device based on the mixed audio signal. The compensated audio signal may have an audio level adjusted based on an estimated loss in loudness associated with the audio level of the remote audio signal.

In one embodiment, a disclosed method for configuring a portable communication device may include receiving an incoming audio signal, adjusting an audio level of the incoming audio signal that is received based on a setting of a volume control, generating an ultrasonic audio signal, mixing the incoming audio signal having the adjusted audio level with the ultrasonic audio signal to generate a mixed audio signal, outputting the mixed audio signal to the remote audio device, receiving a remote audio signal from the remote audio device, and comparing an audio level of the remote audio signal to one or more thresholds to determine whether to output a compensated audio signal to a speaker. The ultrasonic audio signal may have an audio level independent of the setting of the volume control. The remote audio signal may be detected by the remote audio device in response to sound output from the remote audio device based on the mixed audio signal. The compensated audio signal may have an audio level adjusted based on an estimated loss in loudness associated with the audio level of the remote audio signal.

In one embodiment, a disclosed non-transitory, computer-readable storage medium may have program instructions stored thereon that when executed by an electronic processor cause the electronic processor to perform receiving an incoming audio signal, adjusting an audio level of the incoming audio signal that is received based on a setting of a volume control, generating an ultrasonic audio signal, mixing the incoming audio signal having the adjusted audio level with the ultrasonic audio signal to generate a mixed audio signal, outputting the mixed audio signal, receiving a remote audio signal output from the remote audio device, and comparing an audio level of the remote audio signal to one or more thresholds to determine whether to output a compensated audio signal to a speaker. The ultrasonic audio signal may have an audio level independent of the setting of the volume control. The remote audio signal may be detected by the remote audio device in response to sound output from the remote audio device based on the mixed audio signal. The compensated audio signal may have an audio level adjusted based on an estimated loss in loudness associated with the audio level of the remote audio signal.

In at least some embodiments of the present disclosure, the processor configured to compare the audio level of the remote audio signal to one or more thresholds may be further configured to determine whether a battery of the remote audio device has an acceptable level of charge based on the audio level of the remote audio signal being above a first threshold. The determination not to output the compensated audio signal may be based on the determination that the battery of the remote audio device has the acceptable level of a charge. Some embodiments of the present disclosure may include a portable communication device with a microphone configured to detect sound that is output by the remote audio device in which the processor is configured to compare the remote audio signal to an audio signal detected by the microphone to determine whether the remote audio device is defective and enable the microphone of the portable communication device to detect audio signals based on the determination that the remote audio device is defective.

Referring now toFIG. 1, there is provided an illustration of one embodiment of an example electronic communication system100, in accordance with some embodiments. In the illustrated example, electronic communication system100may include portable communication device105, remote audio device110, and secondary remote audio device115. In public-safety or mission-critical environments, portable communication device105may be mounted near the waist of an individual. In certain public-safety or mission-critical environments that are loud, remote audio device110may be communicatively coupled to portable communication device105and mounted near the shoulder of an individual. In even louder environments, secondary remote audio device115may be mounted in or near at least one ear of an individual and communicatively coupled to one or more devices, such as portable communication device105and remote audio device110.

Portable communication device105may support one or more types of communication, including but not limited to audio communication and data communication, using one or more types of transmission, including but not limited to a direct-mode, conventional, or trunked land mobile radio (LMR) standard or protocol such as ETSI Digital Mobile Radio (DMR), a Project 25 (P25) standard defined by the Association of Public Safety Communications Officials International (APCO), Terrestrial Trunked Radio (TETRA), or other LMR radio protocols or standards. In other embodiments, the portable communication device105may support a Long Term Evolution (LTE) (including LTE-Advanced or LTE-Advanced Pro compliant with, for example, the 3GPP TS 36 specification series) or 5G (including a new radio (NR) air interface compliant with the 3GPP TS 38 specification series) protocol, among other possibilities, over which multimedia broadcast multicast services (MBMS), single site point-to-multipoint (SC-PTM) services, or Mission Critical Push-to-talk (MCPTT) services may be provided, or over which an open mobile alliance (OMA) push to talk (PTT) over cellular (OMA-PoC), a voice over IP (VoIP), an LTE Direct or LTE Device to Device, or a PTT over IP (PoIP) application may be implemented. Direct mode LTE standards may additionally or alternatively be implemented as well, including but not limited to the LTE Direct device-to-device standard. Portable communication device105may include speaker120to output sound and one or more microphones, such as microphones125and135, to detect sound. Skilled artisans will appreciate that although one front-facing speaker and two front-facing microphones are shown, portable communication device105may include, in any suitable orientation, any suitable number of speakers to output sound and any suitable number of microphones to detect sound. For example, portable communication device105may include one or more speakers and one or more microphones oriented to be facing any variety of suitable directions, such as front-facing, rear-facing, top-facing, or bottom-facing.

Portable communication device105may include volume control130to adjust the volume of sound output from speaker120. Volume control130may allow for one or more inputs to adjust the volume of sound output from speaker120. For example, volume control130may include one button for increasing the volume and one button for decreasing the volume. Skilled artisans will appreciate that portable communication device105may include a microphone adjustment control to adjust the sensitivity of microphones125and135to detected sound. Volume control and microphone adjustment control may each be implemented as a physical control on the exterior of portable communication device105or as a virtual control displayed on screen122of portable communication device105. Portable communication device105may provide be powered by a portable energy source, such as a battery, whose status may be provided by battery status indicator140. Skilled artisans will appreciate that battery status indicator140may be implemented as a dedicated indicator visible from the exterior of portable communication device105or as a virtual indicator display on screen122of portable communication device105.

Portable communication device105may be communicatively coupled to remote audio device110via an audio communication interface. The audio communication interface may be wired or wireless. For example, a wired audio communication interface may input and output audio signals via audio communication terminal145, remote audio communication connector150, remote audio communication cable155, and remote audio communication terminal156to remote audio device110. As another example, a wireless audio communication interface may use a Bluetooth protocol. In various embodiments, remote audio device110may be implemented as a remote speaker microphone (RSM) accessory to portable communication device105. Remote audio device110may include a remote microphone185to detect sound and remote speaker190to output sound. Skilled artisans will appreciate that any number of speakers and any number of microphones may be included in remote audio device110in any suitable orientation and arrangement. In various embodiments, remote audio device100may include volume control175, remote battery status indicator180, and remote power port195. Volume control175may be used to adjust the volume of sound output from remote speaker190. Remote audio device110may be powered by one or more power sources, including but not limited to a battery in the housing of remote audio device110, remote power port195, and portable communication device via the audio communication interface, such as via audio communication terminal145, remote audio communication connector150, remote audio communication cable155, and remote audio communication terminal156. Remote battery status indicator180may provide the status of the power source for remote audio device110.

Remote audio device110may be communicatively coupled to secondary remote audio device115via any suitable interface, including but not limited to a wired or wireless interface. For example, a wired interface may include secondary remote audio communication terminal160, secondary remote audio communication connector170, and secondary remote audio cable165. Secondary remote audio device115may include a secondary microphone166and secondary speaker168, which may provide additional sound output and sound detection. For example, when remote audio device110is communicatively coupled to secondary remote audio device115, the audio input and output of remote audio device110may be disabled and the low audio fallback approach may be paused.

In various embodiments, portable communication device105may not receive indications from remote audio device110about the status of the remote audio device110, which may indicate a fault with remote audio device110, including but not limited to whether the wired interface to remote audio device110is damaged, whether one or more components of remote audio device110are damaged, such as remote microphone185or remote speaker190, and whether the battery of remote audio device110is depleted. In public-safety or mission-critical environments, a user of the portable communication device105and remote audio device110may be unable to hear or be notified of incoming communications when one or more components associated with remote audio device110are damaged or the battery of remote audio device110is depleted. In various embodiments, the loudness, also known as intensity, of audio output from remote speaker190of remote audio device110may diminish as the battery of remote audio device110approaches depletion. When the battery of remote audio device110is depleted, remote speaker190may output audio at a diminished loudness or may stop output of audio. In various embodiments, portable communication device105may be configured to determine whether there is a fault associated with remote audio device110. When a fault is detected, portable communication device105may enable an individual in public-safety or mission-critical environments to hear or be notified of incoming communications by falling back to use one or more components of portable communication device105, including but not limited to outputting sound via speaker120and detecting sound via microphone125and135.

Referring now toFIG. 2, there is provided a block diagram illustrating selected elements of an example portable communications device200including an application processing unit240, in accordance with some embodiments. In various embodiments, portable communications device200may be a multifunction radio, a mobile telephone, a laptop computer, a tablet computer, a smart phone, or another type of electronic communication device.

As illustrated in this example embodiment, application processing unit240may include a Read Only Memory (ROM)210, a Random Access Memory (RAM)220, an electronic processor230, an input/output interface225, and an external memory interface235, all of which are coupled to a system bus205through which they communicate with each other. In various embodiments, electronic processor230may include a microprocessor, a microcontroller, a system-on-chip, a field-programmable gate array, a programmable mixed-signal array, or, in general, any system or sub-system that includes nominal memory and that is capable of executing a sequence of instructions in order to control hardware elements of portable communications device200.

In this example embodiment, ROM210stores program instructions215, at least some of which may be executed by electronic processor230to perform the methods described herein. For example, at least some of the operations of method400illustrated inFIG. 4, operations of method500illustrated inFIG. 5, operations of method600illustrated inFIG. 6A, or operations of method650illustrated inFIG. 6Bmay be performed by program instructions executing on application processing unit240. In some embodiments, program instructions215may include program instructions that when executed on application processing unit240implement other functionality features of portable communications device200. In some embodiments, program instructions215may be stored in another type of non-volatile memory, such as a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a PROM (Programmable Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory) or a Flash memory. RAM220may, from time to time, store data representing inputs to one or more methods illustrated inFIG. 4,FIG. 5,FIG. 6A, andFIG. 6B, such as data received from one or more of input/output device260through input/output interface225. RAM220may also store data used in performing other functions of the portable communications device200.

In this example embodiment, input/output interface225may include one or more analog input interfaces, such as one or more A/D converters, or digital interfaces for receiving signals or data usable in performing the methods described herein. For example, input/output interface225may include interfaces through which application processing unit240may be coupled to other elements portable communications device200. In the illustrated example, application processing unit240is shown coupled to a transceiver255and one or more input/output devices260. Transceiver255may, at various times, receive audio communications for playback over a speaker, such as speaker120, or transmit audio captured using one or more microphones, such as microphones125and135. One or more components of application processing unit240, such as processor230, may receive an incoming audio signal from transceiver255. In various embodiments, transceiver255may be or include a land mobile radio (LMR) transceiver, a long term evolution (LTE) transceiver, a WiFi transceiver, or another type of audio transceiver. In some embodiments, application processing unit240may be coupled to input/output devices260that implement one or more of a microphone, or a speaker, such as those illustrated inFIG. 1and described above. Any or all of these input/output devices260may be configured to send data to or receive data from application processing unit240over one or more data lines through input/output interface225, in various embodiments. Similarly, any or all of these input/output devices260may be configured to assert or receive a control signal from application processing unit240over one or more connections through input/output interface225. In response to receiving various inputs from input/output devices260, the processor230may execute program instructions to determine how, when, and whether to configure one or more components of portable communications device200, including but not limited to one or more microphones and one or more speakers, based on the status of a remote audio device.

In some embodiments, application processing unit240may be coupled to input/output devices260that implement other functionality features of portable communications device200, such as a keyboard, a mouse, a touch panel, a switch, an additional microphone, a video camera, a display, an additional speaker, an infrared sensor, one or more other sensors, and the like over input/output interface225.

External memory interface235may include one or more interfaces through which application processing unit240may be coupled to an external memory (not shown). Such an external memory may include, for example, a hard-disk drive (HDD), an optical disk drive such as a compact disk (CD) drive or digital versatile disk (DVD) drive, a solid state drive (SSD), a tape drive, a flash memory drive, or a tape drive, to name a few.

Referring now toFIG. 3, there is provided a block diagram illustrating selected elements of an example electronic communication system300, in accordance with some embodiments. Electronic communication system300may include portable communication device302and remote audio device304. In various embodiments, portable communication device302may be implemented as portable communication device200as described forFIG. 2with support for various functionality as described herein using program instructions executed by a processor. Portable communication device302may receive incoming audio signal306, which may be an analog or digital audio signal. For example, an analog audio signal may be received by a transceiver, such as transceiver255as described forFIG. 2. The analog audio signal may be converted to a digital audio signal and processed by one or more components of portable communication device302, including but not limited to an analog-to-digital converter (ADC) and digital signal processor (DSP). Incoming audio signal306may represent one or more communications, including but not limited to an incoming call and an alert notification tone.

The audio level of incoming audio signal306may be adjusted by volume control308for output by a speaker, such as local speaker366or remote speaker328. Volume control308may amplify incoming audio signal306based on a volume control setting for portable communication device302. In various embodiments, volume control308may be implemented using instructions executable by a processor of portable communication device308. For example, volume control130as described forFIG. 1may be used to adjust the audio level of incoming audio signal306. Skilled artisans will appreciate that a plurality of settings may be used to adjust the audio level of a plurality of communications represented by incoming audio signal306. For example, volume control308may include a separate setting for each communication represented by incoming audio signal306. Volume control308may provide adjusted incoming audio signal310to mixer316. Portable communication device302may include an ultrasonic audio signal generator312to provide an ultrasonic audio signal314with an audio level independent of volume control308. In various embodiments, ultrasonic audio signal generator312may be implemented using program instructions executed by a processor. Those instructions, when executed, may provide a digital audio signal with ultrasonic audio information representing sound waves at a frequency above the upper limit of human hearing. For example, the ultrasonic audio signal may represent sound waves at or above 18 kHz. Mixer316may mix adjusted incoming audio signal310with ultrasonic audio signal314to generate mixed audio signal320. Mixed audio signal320may be a digital audio signal with information representing adjusted incoming audio signal310and ultrasonic audio signal314. Mixer316may be implementing using dedicated hardware, such as an audio mixer, or using program instructions executable by a processor.

Audio output of mixed audio signal320may be balanced between portable communication device302and remote audio device304using audio output switch356using remote speaker level adjustment signal352as described in more detail below. Audio output switch356may provide balanced output audio signal322to remote audio device304. Skilled artisans will appreciate that balanced output audio signal322may be provided to remote audio device304as an analog or digital audio signal. Balanced output audio signal322may be received at remote audio communication connection324of remote audio device304. In some embodiments, remote audio communication connection324may be implemented using an audio communication terminal, such as remote audio communication terminal156for remote audio device110as described forFIG. 1.

Balanced output audio signal322may be coupled to power amplifier (PA)326of remote audio device304. Power amplifier326may output amplified mixed audio signal327to remote speaker328to output sound330. Sound330may comprise audio corresponding to the incoming audio signal306and ultrasonic audio signal314. In some embodiments, portable communication device302may drive remote speaker328of remote audio device304when the battery of remote audio device304is depleted for output sound330to be output. Microphone334of remote audio device may detect and be used to capture audio via path332that may represent a reproduction of ultrasonic audio signal314. Microphone334may be located in proximity to remote speaker328to reduce detection of reflected sounds that are output by remote speaker327but reflected off one or more surfaces. Microphone334may provide remote audio signal336to remote audio communication connection324.

Portable communication device302may receive remote audio signal336, which may be input to remote speaker level comparator340. Ultrasonic audio signal314may also be input to remote speaker level comparator340via318. Remote speaker level comparator340may compare remote audio signal336to one or more of ultrasonic audio signal314and one or more thresholds. For example, the ultrasonic audio level of remote audio signal336may be compared to a first threshold. When the ultrasonic audio level of remote audio signal336is above a first threshold, it may be determined that remote audio device304has an acceptable level of charge in its battery. However, when the ultrasonic audio level of remote audio signal336is below the first threshold, the ultrasonic audio level of remote audio signal336may be compared to a second threshold. When the ultrasonic audio level of remote audio signal336is above a second threshold, it may be determined that remote audio device304has a depleted battery. However, when the ultrasonic audio level of remote audio signal336is below the second threshold, the ultrasonic audio level of remote audio signal336may be compared to a third threshold. The third threshold may correspond to no audio level for remote audio signal336. When the ultrasonic audio level of remote audio signal336is equal to the third threshold, it may be determined that remote audio device304is damaged. Otherwise, it may be determined that the remote audio device304is coupled to a secondary remote audio device (not shown) and fallback in audio output from the remote audio device304to the portable communication device302may be disabled. One or more of the thresholds may be predefined or adjusted, such as by calibration or dynamic control. For example, the thresholds may be predefined based on a type of remote audio device. As another example, the thresholds may be adjusted based on dynamic control by an individual or an automated calibration routine.

In some embodiments, remote speaker level comparator340may perform high-pass filtering of remote audio signal336to isolate ultrasonic audio information. High-pass filtering of remote audio signal336by remote speaker level comparator340may be implemented using an audio high-pass filter or by using program instructions that perform high-pass filtering on a digital audio signal when executed by a processor (not shown) in portable communication device302. Remote speaker level comparator340may perform a comparison between remote audio signal336and an ultrasonic audio signal via path318. In various embodiments, the comparison may be performed by a hardware comparator, including but not limited to an op-amp based comparator and a CMOS-based comparator, or by using program instructions that perform comparison between digital audio signals when executed by a processor (not shown) of portable communication device302. Remote speaker level comparator340may output remote speaker level adjustment signal352to control audio output switch356in any suitable manner. For example, audio output switch356may select either balanced output audio signal322or balanced local audio signal360based on output remote speaker level adjustment signal352. As another example, audio output switch356may select either balanced output audio signal322or both balanced output audio signal322and balanced local audio signal360based on output remote speaker level adjustment signal352. Output remote speaker level adjustment signal352may select balanced local audio signal360when it is determined that the battery of remote audio device304is depleted or remote audio device304is damaged.

When balanced local audio signal360is selected, outgoing volume control362may adjust balanced local audio signal360based on compensation value358, which may represent the level of compensation to be applied to the incoming audio information in balanced local audio signal360. For example, compensation value358may be calibrated based on the distance and orientation between one or more components of the remote audio device304, including but not limited to remote speaker328and microphone344of the remote audio device304, and one or more components of portable communication device302, including but not limited to local speaker366and local microphone344of the portable communication device302. As another example, compensation value358may be based on the estimated loss in loudness, which may be determined by a comparison between the ultrasonic audio signal314and the audio level of the remote audio signal336. Outgoing volume control362may output compensated output audio signal364to local speaker366to output audio368.

When microphone344of remote audio device304is defective, portable communication device302may detect the problem and fallback to local microphone344. Remote ultrasonic audio332may be detected and captured using local microphone344of portable communications device302via path342. Microphone344may be implemented using one or more microphones located on one or more sides of portable communications device302to provide local audio signal346. Microphone comparator350may compare the ultrasonic audio level of remote audio signal336via338with the ultrasonic audio level of local audio signal346. The comparison by microphone comparator350may be used to determine whether remote speaker328of remote audio device304or microphone344of remote audio device304is defective. For example, remote speaker328of remote audio device304may be defective when the ultrasonic audio level of remote audio signal336and the ultrasonic audio level of local audio signal346are substantially equal and may each be below a threshold. As another example, microphone344of remote audio device304may be defective when the ultrasonic audio level of remote audio signal336is below the ultrasonic audio level of local audio signal346by any suitable difference, including but not limited to a predefined difference based on the type of remote audio device304and a calibrated difference based on the distance between the remote audio device304and portable communication device302and the orientation of one or more components thereof. Microphone comparator350may be implemented using a hardware comparator, including but not limited to an op-amp based comparator and a CMOS-based comparator, or by program instructions that compare digital audio signals when executed by a processor portable communication device302. When it is determined that microphone344of remote audio device304is defective, local microphone enable signal354may enable microphone344to detect and be used to capture audio for outgoing audio communications.

Referring now toFIG. 4, there is provided a flowchart illustrating selected elements of an example method400for configuring a portable communication device for low audio fallback, in accordance with some embodiments. While a particular order of operations is indicated inFIG. 4for illustrative purposes, the timing and ordering of such operations may vary where appropriate without negating the purpose and advantages of the examples set forth in detail throughout the remainder of this disclosure. For example, method400may operate periodically to configure a portable communication device for low audio fallback.

In this example embodiment, method400begins with block405inFIG. 4and continues with block410, where an incoming audio signal may be received. In some embodiments, the incoming audio signal may be an incoming push-to-talk call or other audio communication. The incoming audio signal may be received by a processor via any suitable path, such as via transceiver255which may be coupled to processor230in application processing unit240as described forFIG. 2. The incoming audio signal may represent communication in analog or digital form. In some embodiments, when the incoming audio signal represents communication in analog form, one or more analog-to-digital converters (ADCs) may be used to convert an analog audio signal to a digital form.

At block415, the method may include adjusting the audio level of the incoming audio signal based on a volume control setting. Skilled artisans will appreciate that the volume control setting may represent one or more physical or virtual controls for the audio level. For example, a separate volume control may be provided for each communication represented by the incoming audio signal, including but not limited to communications corresponding to a push-to-talk call and an alert tone. In some embodiments, the volume control setting may adjust the audio level of the communication associated with the incoming audio signal without adjusting the audio level of other audio information embedded in the incoming audio signal, including but not limited to an alert tone embedded in the incoming audio signal. For example, volume control130of portable communication device105as described forFIG. 1may adjust the audio level of the incoming audio signal. The audio level may be adjusted using any suitable technique, including but not limited to amplification, such as described for volume control308forFIG. 3.

At block420, the method may include generating an ultrasonic audio signal. The ultrasonic audio signal may have an audio level independent of the volume control setting and may provide audio information at a constant audio level. The ultrasonic audio signal may represent audio in the frequency range above the audible range for human hearing, such as between 18 to 20 kHz. In various embodiments, the ultrasonic audio signal may be generated by program instructions when executed by a processor.

At block425, the method may include mixing the incoming audio signal having the adjusted audio level with the ultrasonic audio signal to generate a mixed audio signal. The mixed audio signal may represent a plurality of communications, such as an incoming push-to-talk call, alert tone, and ultrasonic audio tone. Mixing may be preformed by a dedicated audio mixer or program instructions configured to mix audio when executed by a processor.

At block430, the method may include outputting the mixed audio signal to a remote audio device. The remote audio device may receive the mixed audio signal and then output sound representing the mixed audio signal. For example, remote audio device304as described forFIG. 3may receive an audio signal and output sound using remote speaker328. Skilled artisans will appreciate that the remote audio device may perform active or passive amplification of the mixed audio signal. The sound output may be detected and captured using a microphone of the remote audio device, which in turn may output a remote audio signal to the portable communication device.

At block435, the method may include receiving a remote audio signal from the remote audio device. The remote audio signal may be received via a wired connection, such as remote audio signal336as described forFIG. 3, or a wireless connection, such as a connection using a Bluetooth protocol.

At block438, the method may include filtering the remote audio signal to isolate an ultrasonic audio signal within the remote audio signal. Filtering may be implemented as a high-pass filter using analog components, digital logic, or program instructions configured to perform filtering on digital audio when executed by a processor, such as processor230as described forFIG. 2. The high-pass filter may filter audio information below a predetermined frequency such that ultrasonic audio is isolated in the resulting remote audio signal.

At block440, the method may include comparing the audio level of the remote audio signal to one or more thresholds, such as described for method500inFIG. 5. In some embodiments, the thresholds and audio level may be compensated based on the ultrasonic audio tone. When the audio level is below one or more thresholds, it may be determined that the remote audio device cannot output or detect sound. One or more aspects of the remote audio device may inhibit its operation, including but not limited to a depleted battery of the remote audio device that does not have an acceptable level of charge and damage to the audio path of the remote audio device. In various embodiments, the remote audio device may be communicatively coupled to a secondary remote audio device, which may reduce the audio level of the remote audio signal. For example, the speaker of the secondary remote audio device may not sufficiently amplify audio signals representing ultrasonic audio. As another example, the microphone of the secondary remote audio device may not detect sound output by the speaker of the secondary remote audio device or the remote audio device. Accordingly, the audio level of the remote audio signal may be significantly inhibited by the microphone of the secondary remote audio device.

At block445, the method may include determining whether to output a compensated audio signal to a speaker. The determination may be based on the comparison of the audio level of the remote audio signal to one or more thresholds. For example, when the audio level of the remote audio device is above the one or more thresholds, it may be determined that the battery of the remote audio device has an acceptable level of charge and that a compensated audio signal should not be output to the speaker. However, when the audio level of the remote audio signal is below one or more thresholds, it may be determined that the battery of the remote audio device is depleted and does not have an acceptable level of charge or that the audio path of the remote audio device is damaged, and that a compensated audio signal should be output to the speaker. As another example, when the audio level of the remote audio device is at an intermediate level, which may be between one or more thresholds, it may be determined that a secondary remote audio device is communicatively coupled to the remote audio device and that a compensated audio signal should not be output to the speaker. In some embodiments, when it is determined that a secondary remote audio device is communicatively coupled to the remote audio device, method400may be paused for a period to disable low audio fallback from a remote audio device.

When it is determined that a compensated audio signal should be output, method400may proceed to block450where a compensated audio signal may be output to the speaker. The compensated audio signal may have an audio level adjusted based on the estimated loss in loudness and the effective distance between the portable communication device and remote audio device. In various embodiments, the effective distance may be based on the actual distance and orientation between the portable communication device and remote audio device. In various embodiments, the estimated loss in loudness may be associated with the audio level of the remote audio signal and determined based on a comparison between the audio level of the remote audio signal and the ultrasonic audio signal that is generated. For example, compensation value358as described forFIG. 3may provide an indication of the estimated loss in loudness to outgoing volume control362, which may output compensated output audio signal364to local speaker366.

At block460, the method may include displaying an indication representing that the compensated audio signal is output to the speaker. The display may be implemented using a physical indicator, such as a light emitting diode (LED), or a virtual indicator, such as an icon on a display, such as display122of portable communication device105as described forFIG. 1.

When it is determined that a compensation audio should not be output, method400may proceed to block455where a mixed output signal may continue to be output to the remote audio device. At block465, the method may include displaying an indication representing that the compensated audio signal is not output to the speaker. In various embodiments, the display may be implemented using a physical or virtual indicator.

Referring now toFIG. 5, there is provided a flowchart illustrating selected elements of an example method500for comparing the audio level of a remote audio signal with one or more thresholds, in accordance with some embodiments. While a particular order of operations is indicated inFIG. 5for illustrative purposes, the timing and ordering of such operations may vary where appropriate without negating the purpose and advantages of the examples set forth in detail throughout the remainder of this disclosure.

In this example embodiment, method500begins with block502inFIG. 5and continues with block504, where one or more thresholds may be adjusted based on the type of remote audio device. Different types of remote audio devices may output sound with a speaker and detect sound with a microphone resulting in a remote audio signal with varying characteristics, including but not limited to the loudness of the audio represented by the remote audio signal and the frequency response of the audio represented by the remote audio signal. These characteristics may be predetermined based on one or more parameters of different types of remote audio device, including but not limited to specifications of the remote audio device and device characterization of the remote audio device. The type of remote audio device may be defined in any suitable manner, including but not limited to predefining the type of remote audio device, specifying the type of remote audio device by user input, and selecting the type of remote audio device based on an identification of the remote audio device. Skilled artisans will appreciate that adjustments may be made to one or more thresholds or the remote audio signal to provide adjustment based on the type of remote audio device.

At block506, the method may include calibrating one or more thresholds based on the distance between the microphone and speaker of the remote audio device. The sound detected by the microphone may vary based on the distance and orientation between the speaker and the microphone of the remote audio device. A calibration tone may be output by the speaker and detected by the microphone to define the amount of calibration to apply to the one or more thresholds. Skilled artisans will appreciate that calibration information may be applied to one or more thresholds or the remote audio signal to compensate for the distance and orientation between the speaker and the microphone of the remote audio device.

At block510, the method may include determining whether the audio level of the remote audio signal is above a first threshold. The comparison between the audio level of the remote audio signal and one or more thresholds may be performed using a hardware comparator to compare analog audio signals or a processor configured to execute program instructions to compare digital audio signals. When the audio level of the remote audio signal is above the first threshold, it may be determined that the battery of the remote audio device has an acceptable level of charge at block515. When the audio level of the remote audio signal is below the first threshold, it may be determined that one or more problems with the remote audio device result in a lower loudness of audio output from the remote audio device.

At block520, the method may include determining whether the audio level of the remote audio signal is above a second threshold. The second threshold may be less than the first threshold. When the audio level of the remote audio signal is above the second threshold and below the first threshold, it may be determined that the battery of the remote audio device is depleted without an acceptable level of charge at block525. When the audio level of the remote audio signal is below the first and second thresholds, it may be determined that a secondary remote audio device is communicatively coupled to the remote audio device or that an audio path of the remote audio device is damaged.

At block530, the method may include determining whether the audio level of the remote audio signal is above a third threshold. The third threshold may be less than the first and second thresholds. In some embodiments, the third threshold may correspond to the lack of an audio level in the remote audio signal. When the audio level of the remote audio signal is above the third threshold and below the first and second thresholds, it may be determined that the remote audio device is communicatively coupled to a secondary remote audio device at block535. The communicative coupling of the secondary remote audio device may prevent the detection of low audio fallback. When the audio of the remote audio signal is below the first, second, and third thresholds, it may be determined that an audio path of the remote audio device is damaged at540. When the audio path of the remote audio device is damaged, audio output may fall back to the portable communication device.

Referring now toFIG. 6A, there is provided a flowchart illustrating selected elements of an example method600for remote audio device defect determination, in accordance with some embodiments. While a particular order of operations is indicated inFIG. 6Afor illustrative purposes, the timing and ordering of such operations may vary where appropriate without negating the purpose and advantages of the examples set forth in detail throughout the remainder of this disclosure.

In this example embodiment, method600begins with block605inFIG. 6Aand continues with block610, where a remote audio signal may be received from a remote audio device. The remote audio signal may be an analog or digital audio signal, such remote audio signal336as described forFIG. 3.

At block615, the method may include detecting an audio signal using a local microphone. The audio signal may correspond to the sound output by the remote audio device. For example, microphone125or135of portable communication device105as described forFIG. 1may detect an audio signal corresponding to sound output by remote speaker190of remote audio device110. As another example, microphone344of portable communication device302as described forFIG. 3may detect an audio signal via path342. In various embodiments, detection of the audio signal may include conversion of sound waves that are received to an electronic representation of the sound waves, such as a digital or analog audio signal.

At block620, the method may include filtering the remote audio signal to isolate ultrasonic audio. Filtering may be implemented as a high-pass filter using analog components, digital logic, or program instructions configured to perform filtering on digital audio when executed by a processor, such as processor230as described forFIG. 2. The high-pass filter may filter audio information below a predetermined frequency such that ultrasonic audio is isolated in the resulting remote audio signal.

At block625, the method may include filtering the detected audio signal to isolate ultrasonic audio. Filtering of the detect audio signal may be performed in a similar manner to the filtering for the remote audio signal. In some embodiments, the analog components or program instructions may be shared, at least in part, between the filtering of the detected audio signal and remote audio signal.

At block630, the method may include comparing the remote audio signal that is filtered for ultrasonic audio with the detected audio signal that is filtered for ultrasonic audio. The comparison between the remote audio signal and detected audio signal may evaluate the audio levels of the ultrasonic audio in each of the audio signals. For example, microphone comparator350as described forFIG. 3may compare the ultrasonic audio level of local audio signal346with the ultrasonic audio level of remote audio signal336. The comparison may be performed using a hardware comparator to compare analog audio signals or a processor configured to execute program instructions to compare digital audio signals.

At block635, the method may include determining whether the remote audio device is defective based on the comparison between the remote audio signal and detected audio signal. The remote audio device may be determined to be defective when the audio level associated with the remote audio signal is below a threshold corresponding to the audio level of the detected audio signal. In some embodiments, the threshold may be adjusted based on a type of remote audio device and may be calibrated based on the distance and orientation between the remote audio device and the portable communication device. For example, the threshold may be increased by the calibration information when the distance between remote audio device and portable communication device increases because the audio signal detected by the local microphone at block615may have a reduced audio level.

When it is determined that the remote audio device is not defective, method600may proceed to block610. Otherwise, at block640, a local microphone may be enabled to detect audio signals. The fallback from the audio detection of the remote audio device may enable the portable communication device to continue communications when one or more components of the remote audio device, such as the microphone of the remote audio device, are defective.

Referring now toFIG. 6B, there is provided a flowchart illustrating selected elements of an example method650for remote audio device defect determination using ultrasonic audio output, in accordance with some embodiments. While a particular order of operations is indicated inFIG. 6Bfor illustrative purposes, the timing and ordering of such operations may vary where appropriate without negating the purpose and advantages of the examples set forth in detail throughout the remainder of this disclosure.

In this example embodiment, method650begins with block605inFIG. 6Band continues with block608, where ultrasonic audio is output using a local speaker. For example, local speaker366as described forFIG. 3may output ultrasonic audio based on the ultrasonic audio signal214.

At block610, the method may include receiving a remote audio signal from a remote audio device, as the described for block610ofFIG. 6A. At block615, an audio signal may be detected using the local microphone. The audio signal may correspond to the ultrasonic audio output using the local speaker at block608. For example, microphone125or135of portable communication device105as described forFIG. 1may detect an audio signal corresponding to sound output by local speaker120of portable communication device105.

At block630, the method may include comparing the remote audio signal having ultrasonic audio with the detected audio signal having ultrasonic audio, such as described for block630ofFIG. 6A.

At block635, the method may include determining whether the remote audio device is defective, such as described for block635ofFIG. 6B. One or more components of the remote audio device may be defective, such as the speaker of the remote audio device.

When it is determined that the remote audio device is not defective, method650may continue to block608. Otherwise, at block640, a local microphone may be enabled to detect audio signals. In some embodiments, the local speaker may also be enabled to output sound. The fallback from the audio detection of the remote audio device may enable the portable communication device to continue communications when one or more components of the remote audio device, such as the speaker of the remote audio device, are defective.

In at least some embodiments, the systems, methods, and apparatus described herein for configuring a portable communication device for low audio fallback may provide technical benefits when compared to existing techniques for audio communications. The described techniques use ultrasonic audio, without user intervention, to determine whether an existing remote audio device, without any modification to the remote audio device, has one or more problems, including but not limited to a depleted battery, damaged audio path, defective remote speaker, and defect remote microphone. The described techniques include detecting when a secondary audio device is being used for audio communications to avoid false activations of low audio fallback. The determination whether an existing remote audio device has a problem includes an approach to mix an ultrasonic audio tone with an incoming audio signal, communicate the mixed audio signal to the remote audio device, receiving a remote audio signal from the remote audio device that represents the ultrasonic audio tone, and comparing the audio level of the remote audio signal that is associated with the ultrasonic audio tone to one or more thresholds. This approach provides for adjustments to the portable communication device's speaker volume to compensate for the loss in audio playback loudness from the remote audio device. Systems without low audio fallback require user invention, without any notification to the user, to replace or disable remote audio devices with one or more problems. For example, some types of remote audio devices may stop audio output when the battery of the device is depleted and thus a user may not be able to notice the problem or distinguish a depleted battery from a pause in audio communications. Other systems may enable a user to disable communications via remote audio devices, but may require user intervention to determine the appropriate loudness of the local speaker. By comparing the signal level of the generated ultrasonic audio tone to the remote audio signal detected at the remote audio device, the described techniques may dynamically adjust the loudness of the local speaker.

In addition, unlike some existing approaches, the techniques described herein do not require modifications to the hardware of the portable communication device or remote audio device. Instead, the techniques described herein may use existing radio capabilities without any hardware changes.