Communication channels between a personal communication device and at least one head-worn device

A hearing assistive system, comprises a personal communication device (10) and a head-worn device (20). The personal communication device (10) has a user interface (12) being adapted for user interaction, a processor (11) controlling the user interface (12) and being adapted to run an application program, a short-range radio (13), and an output transducer (15). The head-worn device (20) has an input transducer (24) adapted for converting sound into an electric signal applied to a processor (21) outputting a modified audio signal via an output transducer (25). The application program is adapted to generate and output a data packet (70) on an audio carrier via the output transducer (15). The head-worn device (20) has an audio signaling block (26) for detecting and decoding the data packet (70) received by the input transducer (24). The head-worn device (20) has a controller (27) for controlling the operation of a short-range radio (28). The audio signaling block (26) is adapted to detect a radio pair command included in the data packet (70), and to instruct the controller (27) to enter pairing mode for the short-range radio (28), accordingly.

BACKGROUND OF THE INVENTION

The present invention relates to hearing assistive system, comprising a personal communication device and at least one head-worn device. The invention, more particularly, relates to a method for handling audio-based communication between the personal communication device and the at least one head-worn device, a method of controlling the head-worn device remotely from the personal communication device, a personal communication device and a computer-readable storage medium having computer-executable instructions for carrying out the invention.

SUMMARY OF THE INVENTION

The purpose of the invention is to provide a hearing assistive system for controlling the radio-frequency signal transmission from a head-worn device.

According to the invention, this purpose is achieved by a hearing assistive system, comprising a personal communication device and a head-worn device. The personal communication device has a user interface being adapted for user interaction, a processor controlling the user interface and being adapted to run an application program, a short-range radio, and an output transducer. The head-worn device having an input transducer adapted for converting sound into an electric signal applied to a processor outputting a modified audio signal via an output transducer. The application program is adapted to generate and output a data packet on an audio carrier via the output transducer. The head-worn device has an audio signaling block for detecting and decoding the data packet received by the input transducer. The head-worn device comprises a controller for controlling the operation of a short-range radio. The audio signaling block is adapted to detect a radio pair command included in the data packet, and to instruct the controller to enter pairing mode for the short-range radio, accordingly.

In one embodiment, the head-worn device is a hearing assistive device, and the processor is configured to compensate a hearing loss of the hearing assistive device user.

According to a second aspect of the invention there is provided a method of controlling a head-worn device remotely from a personal communication device. The personal communication device has a user interface being adapted for user interaction, a processor controlling the user interface and being adapted to run an application program, a short-range radio, and an output transducer. The head-worn device comprises an input transducer adapted for converting sound into an electric signal applied to a processor outputting a modified audio signal via an output transducer, an audio signaling block for detecting and decoding the data packet received by the input transducer, and a controller for controlling the operation of a short-range radio. The method comprises generating and outputting a data packet on an audio carrier via the output transducer of the personal communication device; and receiving the data packet in head-worn device. The audio signaling block is adapted to detect a radio pair command included in the data packet, and to instruct the controller to bring the short-range radio into pairing mode for a predetermined period of time.

According to a third aspect of the invention there is provided a head-worn device has an input transducer adapted for converting sound into an electric signal applied to a processor, the processor being configured to output a modified audio signal via an output transducer. The head-worn device further comprises a short-range radio controlled by a controller, and an audio signaling block for detecting and decoding a data packet sent via an audio carrier and received by the input transducer. The audio signaling block is adapted to detect a radio pair command included in the data packet, and to instruct the controller to bring the short-range radio into pairing mode, accordingly.

DETAILED DESCRIPTION

The current invention relates to a head-worn device20, preferably embodied as a hearing assistive device being adapted to at least partly fit into the ear of the wearer and amplify sound. Hearing assistive devices include Personal Sound Amplification Products and hearing aids. Both Personal Sound Amplification Products (PSAP) and hearing aids are small electroacoustic devices which are designed to process, amplify or limit sound for the wearer. Personal Sound Amplification Products are mostly off-the-shelf amplifiers for people with normal hearing who need a little adjustment in volume (such as during hunting, concerts or bird watching).

Reference is made toFIG. 1, which schematically illustrates a first embodiment of a hearing assistive system, comprising a personal communication device10and a head-worn device20according to the invention. The head-worn device20according to the embodiment shown inFIG. 1is a hearing aid or a hearing assistive device. The personal communication device10may e.g. be a smartphone with an advanced mobile operating system that combines features of a personal computer operating system with features useful for mobile or handheld use.

The head-worn device20or the hearing assistive device has at least one input transducer or microphone24picking up an audio signal and transforming it into an analog signal. An analog-to-digital converter22(e.g. a delta sigma converter) receives the analog signal and provides a digital signal for a digital signal processor21. The digital signal processor21is preferably a specialized microprocessor with its architecture optimized for the operational needs of digital signal processing, and in the illustrated embodiment the processor21is adapted for amplifying and conditioning of the audio signal intended to become presented for the hearing aid user. The amplification and conditioning is carried out according to a predetermined setting stored in a non-volatile memory7(e.g. an EEPROM) in order to alleviate a hearing loss by amplifying sound at frequencies in those parts of the audible frequency range where the user suffers a hearing deficit.

According to the illustrated embodiment of the invention the processor21outputs a digital signal fed to a digital output stage23and an output transducer or a speaker25. The speaker25may be driven as a class D amplifier by the one-bit digital data stream received.

The hearing assistive device includes a controller27which according to the illustrated embodiment is controlling the operation of a short-range radio28and a magnetic induction radio29. The short-range radio28is preferably operating according to the Bluetooth™ protocol. Bluetooth™ is a wireless technology standard for exchanging data over short distances using the ISM band from 2.4 to 2.485 GHz. Bluetooth™ is widely used for short-range communication, for building personal area networks (PAN), and is employed in most mobile phones. Bluetooth™ Low Energy (BLE) has a fixed packet structure with two types of packets; Advertising and Data. The data packets may contain payload as audio for audio streaming or instructions for programming the hearing assistive device. Programming includes two different aspects—acoustic programming refers to setting parameters (e.g. gain and frequency response) affecting the sound output to the user, which carries risk of potentially damaging the residual hearing by making wrong settings; and operational programming refers to settings which do not affect the sound significantly, such as volume control and selection of environmental programs.

The hearing aids20according to the illustrated embodiment are provided to a hearing-impaired user as a set of binaural hearing aids. The magnetic induction radio29provides a low power communication channel for an inter-ear communication between the two hearing aids20. The magnetic induction radio29may operate as a Near-Field Magnetic Induction (NFMI) communication system as known for WBAN systems and may apply FSK modulation, which is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier signal. The operational range for magnetic induction radios29is relatively short; less that 1-2 meters, and with low power as used in hearing assistive devices, the range may preferably be in the range of 20-30 cm. The standard modulation schemes used in typical RF communications (amplitude modulation, phase modulation, and frequency modulation) can be used in near-field magnetic induction system. As an alternative to FSK modulation, PSK modulation or m-ary FSK modulation may be applied. FSK modulation will be robust even in the absence of line of sight between the transmitter and the receiver, while PSK modulation will have a better modulation form for specific use cases. The magnetic induction radio29may be used for exchanging audio between the binaural hearing aids20, for exchanging control parameters between the binaural hearing aids20, or for synchronizing the binaural hearing aids20.

Furthermore, the processor21incorporates according to one embodiment of the invention an audio signaling block (ABS)26for detecting and decoding one or more data packets received by the input transducer24. In another embodiment, the audio signaling block26is adapted for modulating and coding one or more data packets originated from the processor21and to be output from the head-worn device20via the digital output stage23and the output transducer or speaker25.

The head-worn device20includes a replaceable battery6for powering the electronic components. A push button5is illustrated for switching the power on and off. In practice the powering on and off is controlled by opening and closing a battery door present in the housing of the head-worn device20. The head-worn device20furthermore includes a push button switch8providing the user interface for controlling the operation of the head-worn device20. The function of the push button switch8depends on the current mode of head-worn device20.

The personal communication device10may as mentioned earlier be able to communicate with the head-worn device20via respective radios supporting e.g. Bluetooth communication, and in addition to this, the personal communication device10is according to one embodiment of the invention able to transmit a signal40based upon an acoustic coding scheme to the head-worn device20. In one embodiment, the head-worn device20may provide a response signal41to the personal communication device10based upon a similar acoustic coding scheme as indicated with the arrows40and41inFIG. 1.

FIG. 2illustrates the basic elements of a personal communication device10. The personal communication device10includes a general-purpose processor11, which is a central processing unit (CPU) that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. The general-purpose processor11is associated with memory16forming a computer-readable storage medium having computer-executable instructions.

The personal communication device10includes a microphone14for picking up audio, primarily speech, and generating an electronic representation for the audio signal to be fed to the general-purpose processor11. As modern smartphones are multi-radio devices having radio interfaces towards cellular networks as GSM, WCDMA and LTE, short-range networks as WLAN and Bluetooth™, and for positioning as GPS, the personal communication device10includes a connectivity manager18managing telephone calls, data transmission and data receiving via a multi-mode radio including a short-range radio13. The personal communication device10includes a user interface12, such a touchscreen, enabling the user to interact directly with what is displayed.

FIG. 2illustrates that user interface12displays a screen shot for a hearing aid control app19aincluding the audio modulator according to the invention. The screen shot for the hearing aid control app19aincludes a header12ainforming the user about the hearing aid program currently selected, here “Music stream”. The user may select the appropriate program by swiping and tapping the control area comprising the header12a. The list of available hearing aid programs includes traditional hearing aid programs optimized for specific listening situations, streaming programs for streaming audio, telephone conversation or music from the personal communication device10to the head-worn device20, and a specific flight mode program where the short-range radio link between the personal communication device10and the head-worn device20is shut down. The screen shot for the hearing aid control app19aincludes further controls, often hearing aid program dependent. A volume control area12bindicates the current volume by means of a movable bar informing the user about the current volume level relative to the volume range permitted for user adjustment and marked by a triangle permitting the user to slide the movable bar between min and max of the permitted volume range. A hearing aid program control area12cpermits the user to stop the music stream. The user may select the appropriate program by swiping and tapping the hearing aid program control area12c.

The personal communication device10includes a speaker15for output delivered from the general-purpose processor11.

The memory16is illustrated as one unit, but a man skilled in the art is aware that a computer memory comprises a volatile memory part acting as working memory (Random-Access Memory) and requiring power to maintain the stored information, and a non-volatile memory part (e. g. Read-Only Memory, flash memory) in which stored information is persistent after the personal communication device10has been powered off.

The memory16may contain computer-executable instructions for a plurality of application programs19(apps) including an audio modulation app19a. The application programs19may be downloaded from an app store on a remote server or pre-stored in the personal communication device10from factory. The general-purpose processor11runs the computer-executable instructions for the audio modulation app19aand provides an application program having a user interface12being adapted for user interaction. The audio modulation app19aincludes computer-executable instructions for generating a command, often in response to a user interaction, embedding the command in data for at least one data packet70, modulating the data according to a predetermined acoustic coding scheme, and outputting the data packet70on an audio carrier via the output transducer15intended for the head-worn device20. The command contained in the data packet70controls the mode of the head-worn device20. According to the invention, the command contained in the data packet70controls the mode of a radio of the head-worn device20.

One embodiment for a data packet70according to the invention is illustrated with reference toFIG. 6. The data packet70comprises control information and user data, which is also known as the payload. The control information may preferably be a header71, e.g. a sync word or a preamble used to synchronize a data transmission and being a known sequence of data used to identify the start of a frame. The payload72may contain predetermined commands instructing the head-worn device20to perform predetermined actions upon reception of the command. The payload72may also contain instructions to store transmitted data in specified memory locations of the head-worn device20. Furthermore, the data packet70includes in the illustrated embodiment a cyclic redundancy check (CRC) segment73comprising an error-detecting code adapted for detecting accidental changes to raw data. The data packet70has a short check value attached, based on the remainder of a polynomial division of their contents. On retrieval, the calculation is repeated and, in the event the check values do not match, corrective action can be taken against data corruption.

FIG. 3illustrates an embodiment of a head-worn device20according to the invention comprising the audio signaling block26. The audio signaling block26receives the signal picked up by the microphone24and converted into a digital representation by the analog-to-digital converter22from a branch from the signal path in the processor21. In the illustrated embodiment, Frequency-Shift Keying (FSK) is applied as a modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier signal.

At the input of the audio signaling block26, a DC filter31removes DC offset present in the digital signal. A mixer32removes a carrier frequency by mixing down the received signal to base band. Preferably, the carrier frequency is predefined in the range of 8-18 kHz ensuring that the data packet70is present at a sufficiently high frequency in order not to disturb the environment by making an annoying sound and in order that the data packet70is present at a sufficiently low frequency so a hearing aid microphone24and smartphone speaker15and/or microphone14can pick up or, respectively, output the sound. Preferably, the mixer32creates an in-phase (I) component as well as a quadrature (Q) component being shifted 90° in phase relatively to the in-phase (I) component.

An FSK demodulator33receives the in-phase (I) component and the quadrature (Q) component and uses a conventional matched filter approach in FSK to detect which frequency the incoming signal has. Preferably, the received signal is mixed with the possible signal frequencies, and the resulting signal with the highest level corresponds to the transmitted frequency. The highest magnitude for the various frequencies is selected and the corresponding symbol is assigned.

An FSK detector34is adapted to detect the start of the data packet70based on the data contained in the header71, to validate an error free reception based upon the error-detecting code contained in the cyclic redundancy check (CRC) segment73, and to take corrective action against data corruption if possible. When the data packet70has been successfully detected, the FSK detector34extracts the payload72and supplies data to a controller27. The controller27translates the data received from the FSK detector34into commands to perform predetermined actions or into instructions to store transmitted data in specified memory locations of the head-worn device20.

According to the invention, the audio modulation app19aof the personal communication device10has a modulator for modulating audio data signals targeted for the head-worn device20. The audio signaling block26of the head-worn device20demodulates the audio data signal and extracts the content. In some embodiments the audio signaling block26of the head-worn device20has a modulator for modulating audio data signals targeted for the personal communication device10. For this purpose, the audio modulation app19aof the personal communication device10has demodulation facilities for demodulating the audio data signal and extracting the content. Hereby a return way for remote control commands is established, and the head-worn device20may acknowledge that a command has been received successfully and that the instructions have been carried out. The personal communication device10may retransmit a command if the head-worn device20has not acknowledged the reception of an original command within a predetermined period of time.

The invention is also applicable in a fitting situation as the personal communication device10transmits data packets to the head-worn device20. The data packets70contain instructions to store transmitted data in specified memory locations of the head-worn device20. The transmitted data comprise settings by which the processor21is adapted to alleviate a hearing loss by amplifying sound at frequencies in those parts of the audible frequency range where the user suffers a hearing deficit. The personal communication device10successively transmits programming data packets70, for each packet awaiting a responding data package from the head-worn device20verifying that the previous programming data packet70has been successfully received and handled.

When the controller27identifies a need for sending a message to the personal communication device10, a response unit35is instructed to prepare an appropriate command for a data packet70. The data packet70is then transferred to a modulator36providing the audio FSK modulation. The audio FSK modulated data packet70is added to the output from the DSP processor21in a summation point37, and thereafter converted to sound by means of the output stage23and the speaker25.

The audio signaling block26includes a detector block (the DC filter31, the mixer32, the FSK demodulator33, and the FSK detector34) adapted to detect and decode the data packet (70) received by the input transducer (24); and a response block (response unit35and the modulator36) adapted to generate a data packet (70) modulated on an audio carrier and output via the output transducer (25).

The commands from the personal communication device10may include a radio control command, such as a “radio disable command” or a “radio enable command”. These commands control the radios of the head-worn device20. In one embodiment, the short-range radio28is a Bluetooth radio with a 10-meter range, and thereby compelled by the guidelines from Federal Aviation Administration to be suspended in certain situations (The U.S. Department of Transportation's Federal Aviation Administration (FAA) announced in 2013 that it has been determined that airlines can safely expand passenger use of Portable Electronic Devices (PEDs) during all phases of flight.). The magnetic induction radio29has a significantly shorter range and the inter-ear communication between two head-worn devices20will therefore not have to be suspended according to the guidelines from Federal Aviation Administration. When the head-worn devices20in a radio enabled mode60(e.g. normal hearing aid mode), as illustrated with reference toFIG. 4, receive a “radio disable command”, the controller27suspends or disables the short-range radio28and enters a radio disabled mode62(e.g. the flight mode) as indicated by the arrow64. The head-worn device20stays in this mode until the controller27receives a “radio enable command” from the audio signaling block26. Then the controller27enables the short-range radio28and enters the radio enabled mode60as indicated by the arrow63.

According to one embodiment, the audio modulation app19ais controlled by the connectivity manager of the personal communication device10. When the user turns the personal communication device10into flight mode as prescribed by guidelines from Federal Aviation Administration, the audio modulation app19ainterprets the mode change of the personal communication device10as a trigger for automatically instructing the head-worn device20to follow the mode change by automatically sending a “radio disable command”. Hereby the head-worn device20follows the mode of the personal communication device10and enters and leaves automatically the radio disabled mode62without any head-worn device20dedicated user interaction.

When a user receives a new head-worn device20and he intends to pair a personal communication device10to the head-worn device20, according to one embodiment of the invention, the user downloads an app having an audio signaling block26according to the invention and the user initiates the transmission of a “radio pair command”. The head-worn device20will while un-paired be in the radio disabled mode68.

When the audio signaling block26detects a “radio pair command” included in the data packet70, the controller27initiates a pairing mode61for the short-range radio link between the personal communication device10and the head-worn device20. The entering of paring mode is indicated with an arrow66and is normally initiated from the radio disabled mode68. Hereby it becomes easier to pair the two devices, as the head-worn device20no longer needs to be re-booted to initiate paring mode61. The head-worn device20remains in pairing mode61for a predetermined period of time, e.g. 2 minutes, or until pairing has been completed. If pairing was successful, the head-worn device20enters the radio enabled mode60as indicated by an arrow65. If no pairing has been achieved after the predetermined period of time, the head-worn device20resumes the radio disabled mode68as indicated by an arrow67.

It is also possible for the head-worn device20to enter pairing mode61from the radio enabled mode60in case the user indicates via the app that he intends to pair the head-worn device20with an additional personal communication device10. The “radio pair command” may in one embodiment include a user ID previously linked to and known by the personal communication device10.

According to one embodiment of the invention, the reception of a radio control command will cause the processor21, when the contained instruction has been executed, to retrieve a pre-recorded or pre-synthesized speech sequence from an associated memory7of the head-worn device20and play the speech sequence via the speaker25verifying for the user that the instruction has been executed. The “radio disable command” may have an associated speech sequence output saying: “flight mode has been entered”.

FIG. 5illustrates the communication paths between the personal communication device10and the two head-worn devices20-Left and20-Right according to one embodiment of the invention. The two head-worn devices20-Left and20-Right each includes the magnetic induction radio29(FIG. 1) being responsible for the inter-ear communication75between two head-worn devices20. The inter-ear communication75is not regulated by the flight mode guidelines from Federal Aviation Administration and may therefore be mode independent and enabled whenever the two head-worn devices20-Left and20-Right are in operation.

The short-range radio link76and77between the personal communication device10and the respective one of the two head-worn devices20-Left and20-Right is in one embodiment provided by respective Bluetooth radios, and thereby required by the guidelines from Federal Aviation Administration to be suspended. The short-range radio links76and77are mode dependent and will be enabled when the personal communication device10and the two head-worn devices20-Left and20-Right all are in radio enabled mode60or pairing mode61.

The acoustic communication link78and79between the personal communication device10and the respective one of the two head-worn devices20-Left and20-Right is according to the invention provided by the audio modulator app19ain the personal communication device10and the audio signaling block26of the respective one of the two head-worn devices20-Left and20-Right. The acoustic communication link78and79is not subject to the flight mode guidelines from Federal Aviation Administration and is enabled when the two head-worn devices20-Left and20-Right and the personal communication device10are in operation. The means that the personal communication device10is able to act as remote control while the two head-worn devices20-Left and20-Right are in flight mode62, and, very importantly be able to bring back the two head-worn devices20-Left and20-Right to normal radio enabled mode60again.

During a binaural fitting session based upon the acoustic communication link78and79(in case these are one-way), the inter-ear communication link75based upon an inductive link may improve robustness as the two head-worn devices20-Left and20-Right may detect the same acoustically transmitted data. Then the acoustically transmitted data is exchanged/negotiated by the two head-worn devices20-Left and20-Right via the inter-ear communication75. This may reduce the head shadow effect, that may limit robustness when sending packets to a contra laterally positioned head-worn device20(hearing aid) relative to the personal communication device10(smartphone).

Two-Way Acoustic Communication Link

The acoustic communication link78and79may operate well as one-way communication channels, but from an error-control perspective, it is desired that either the hearing aid user receives some kind of notification about that a transferred have been successfully received as indicated earlier by playing back a pre-recorded sequence.

However, it is preferred that the personal communication device10and the two head-worn devices20-Left and20-Right are able to establish a signaling dialog. This may be beneficial in e. g. a hearing aid fitting procedure, a pairing procedure, a self-test procedure or a remote fitting procedure.

In one embodiment, the two head-worn devices20-Left and20-Right can only listen on one channel at a time. The personal communication device10may initiate a two-way acoustic communication link78and79by instructing the two head-worn devices20-Left and20-Right to apply a specific frequency channel which may be in the audible range and may have higher data capacity. The two head-worn devices20-Left and20-Right of a binaural set of hearing aids could be assigned different sync words71to effectively establish two two-way acoustic communication links78and79.

On each acoustic communication link78and79, the personal communication device10would send a packet70and listen for answer from the two head-worn devices20-Left and20-Right. If a response is received, the personal communication device10will send a new packet70—otherwise it will resend the last packet after a certain period of time. This error control method is called Automatic Repeat reQuest (ARQ) and may be used for establishing a reliable link. The communication protocol on top of the physical layer can include: an ARQ scheme, separate control and user planes (control plane could be used to communicate about e.g. encryption or transmission speed), fragmentation of long payloads, multiplexing of logical channels.

Using the acoustic communication links78and79for two-way communication requires that there is a substantially free line of sight between the transducers (microphones and speakers) of the personal communication device10and the head-worn devices20and a short distance, preferably be less than 20 cm, and even better below 10 cm.

Fitting

The smallest hearing aids available on the market, e.g. Completely-In-Canal (CIC) hearing aids, are often offered without radios to minimize its volume. This means that the hearing aid has no Bluetooth radio or inductive radio for providing a reliable link for programming or fitting. According to the invention, the acoustic communication link78and79may be used for transferring fitting data (settings) to the hearing aids to alleviate the hearing loss of the user.

In this scenario the personal communication device10updates the fitting data of the hearing aids or the head-worn devices20by writing fitting data to the non-volatile memory7(e.g. EEPROM). The scenario also covers fine-tuning which differs from the initial hearing aid fitting in the amount of data transferred. By transferring fitting data in smaller packets, the fitter may monitor the progress of the transfer as the head-worn devices20reports the successful reception during the fitting process. Especially in the case of fine-tuning taking place remotely via the Internet (from the computer of the audiologist via the smart phone app19a), the writing of EEPROM data can be accomplished directly from the personal communication device10(smartphone) with no intermediary fitting assistive devices. The app19aof the personal communication device10may also read log data from the head-worn devices20and send these to the clinic (audiologist) or a central server for use in a data-driven update of the fitting. The remote fine-tuning may also be an update that the personal communication device10generates based on the user's input to e.g. Interactive Personalization as described in WO2016004983 A1. If the user wants to store the settings permanently (e.g. as a new program), the personal communication device10needs to write data to the non-volatile memory7(EEPROM) and require acknowledge in this process.

Acoustic Communication Pairing

In order to improve security for the acoustic communication links78and79, a pairing procedure for the personal communication device10and the two head-worn devices20-Left and20-Right may be set up. During the acoustic communication pairing, the personal communication device10and the two head-worn devices20-Left and20-Right may define a communication ID for each of the two acoustic communication links78and79. The communication ID is used in packets sent on the one-way link (e.g. remote control commands) in order to ensure that the users personal communication device10is the only device permitted to control the two head-worn devices20-Left and20-Right.

The communication ID can be e.g. an 8 or 10-bit sequence that must be contained or otherwise encoded into the data packet, e.g. in the sync word71or the payload72. The two head-worn devices20-Left and20-Right will react only to packets containing the correct communication ID. Advantageously, the communication ID may be generated by the head-worn devices20-Left and20-Right (or programmed by the fitting software used when fitting a hearing aid or embedded into the hearing aid during the production). This enables that one or more personal communication devices10may be paired with the hearing aid.

As the two-way acoustic communication link78and79requires the head-worn devices20-Left and20-Right (e.g. hearing aids) are currently not worn, the use of acoustic communication pairing as a pre-pairing for a later Bluetooth pairing provides an improved protection against spurious Bluetooth pairings. For instance, if the hearing aids are available for one-way Bluetooth pairing for 2-3 minutes after boot, the chance of a spurious pairing is more likely than if the hearing aids must be placed next to the phone to make two-way acoustic communication pairing.

The two-way acoustic communication pairing allows the personal communication device10to read the program stack of the head-worn devices20-Left and20-Right for display on the display. This is an improved user experience.

If different hearing aid models use different acoustic communication channels (frequencies, modulation type and speed), the personal communication device10may try all of these and thus find the appropriate one for the specific hearing aid model. This allows that the hearing aid manufacturer may change the communication channel for one-way communication mode from series to series, and just must update the app19afor adding new communication channels (frequencies, modulation type and speed).

The two-way acoustic communication link78and79may be used to enable a self-test of the hearing aid (head-worn device20) and report data back to the personal communication device10to display for the user or to send report data to an audiologist at the clinic. The self-test may ensure that different parts of the electronics function as desired or ensure the integrity of the non-volatile memory7(e.g. EEPROM) by checking e.g. a hash value.

The two-way acoustic communication link78and79may also be used to read out metrics related to the current hearing aid performance, e.g. battery level, active sound classes or other parameters logged by a logging function built into the hearing aid or related to the hearing aid performance/usage. The self-test is carried out by placing the personal communication device10adjacent to the hearing aids, e.g. on a table. By placing the personal communication device10and the head-worn devices20adjacent to each other, it is avoided that the hearing aids are not worn during the self-test, as these are resting safely in the table. Therefor the potential risk of generating loud sounds by the hearing aids in the ear of a user is eliminated.

Furthermore, hearing aids may not operate as in normal mode when performing the self-test, and therefore it is an advantage to know that the hearing aids are not being worn. Furthermore, it will be possible to read-out performance data from the HA without a radio connection, e.g. Bluetooth or magnetic induction (NFMI).

FIG. 7illustrates a two-way communication pattern between the personal communication device10and one of the head-worn devices20. The data session is spilt up in smaller sub-sections, #1-#n. Each sub-section is in the illustrated embodiment initiated by the personal communication device10transmitting a sub-session initiating data packet80.1. In response to the reception of the initiating data packet80.1, the head-worn device20transmits a responding data packet81.1, e.g.confirming a successful reception of the initiating data packet80.1;confirming a successful execution of instructions contained the initiating data packet80.1;confirming a successful writing in a memory of data contained the initiating data packet80.1; orcontaining data read from a memory specified by data contained the initiating data packet80.1.

This communication pattern is controlled by the personal communication device10, and is continued until all subsection, #1-#n, have been completed successfully.

FIG. 8illustrates as flow chart for the transmission process in the two-way communication session as illustrated inFIG. 7. In step90, the personal communication device10transmits a sub-session initiating data packet80.1and waits in step91for a response from the head-worn device20. If the personal communication device10receives a responding data packet81.1within a predefined time limit, e.g. 8 seconds, from the head-worn device20, the personal communication device10deems the first sub-section of the data section to be successfully completed and progresses to step92, in which the personal communication device10checks whether further data packets are present in a transmission queue. If this is the case, the personal communication device10transmits the next sub-session initiating data packet80.2and waits, in step91, for a response. The loop is repeated until the personal communication device10, in step92, find the transmission queue empty. Then the personal communication device10deems the data session to be completed and displays, in step94, a notification in the display12for the manual operator of the personal communication device10and terminates, in step95, the session. The retransmission counter is reset.

In case the personal communication device10does not receive the responding data packet81.1within a predefined time limit in step91, the personal communication device10checks, in step96, whether the number of retransmissions has exceeded a predefined number. The predefined may be set to a fixed number, e.g. 8, or to a floating number depending on the number of planned sub-sections, e.g. one per sub-section. If the predefined number of retransmission has not been reached yet, the personal communication device10retransmits the same sub-session initiating data packet80.1, increments the retransmission counter by one, and waits, in step91, for a response.

If the personal communication device10, in step96, detects that the number of retransmissions has exceeded a predefined number, the personal communication device10interrupts, in step98, the data session and displays an error message for the manual operator of the personal communication device10providing hints about establishing a better connection (lees noisy environment, recommended positioning for the head-worn devices20relatively to the personal communication device10etc.). The personal communication device10and terminates, in step95, the session and resets the retransmission counter.