The invention relates to a method of establishing a wireless network comprising a first and a second hearing assistance device and an external device.

In general, establishing a communication network requires two steps: first, the devices have to be paired, and then the devices have to be connected. The pairing procedure typically involves the exchange of a device identification and information related to security, e.g. information for deriving a shared encryption key; the connection procedure involves the exchange of information concerning network protocol and timing (i.e. in order to synchronize to a network clock), frequency hopping sequence, etc. From a network protocol's perspective, two devices, such as hearing assistance devices, are considered as separate devices, so that, in order for the two devices to communicate with a third device, the two devices need to be individually paired with the third device, thereby requiring two separate pairing interactions. From a user's perspective, pairing interactions are cumbersome and therefore should be avoided as far as possible.

EP 1 701 567 A1 relates to a communication method wherein a first Bluetooth device which is paired to a second Bluetooth device uses the connectivity of the second device to a network for accessing the network. WO 03/056746 A1 relates to a communication system comprising a plurality of devices, wherein a group encryption key is established and distributed among the devices in order to simplify pairing of the devices.

US 7,813,762 B1 relates to a wireless communication adapter which is connected to a direct audio input of a BTE hearing aid in order to connect the hearing aid with a remote device. The adapter uses a Bluetooth standard and is provided with a multi- pairing capability.

It is an object of the invention to provide for a method of establishing a wireless network comprising a first and a second hearing assistance device and an external device, wherein pairing can be achieved in a particularly simple manner, it is a further object to provide for a corresponding hearing assistance system. According to the invention, these objects are achieved by methods as defined in claims 1 , 3 and 7 and systems as defined in claims 22, 23 and 24, respectively.

The invention is beneficial in that, using one of the two hearing assistance devices for assisting pairing of the other hearing assistance device with the external device, the pairing procedure can be simplified from a user's perspective by reducing the user's interactions required to achieve pairing of the two hearing assistance devices with the external device. Preferably, the network uses a Bluetooth protocol.

Preferred embodiments of the invention are defined in the dependent claims.

Hereinafter, examples of the invention will be illustrated by reference to the attached drawings, wherein:

Fig. 1 is a schematic block diagram of an example of a hearing assistance system according to the invention;

Fig. 2 is a sequence diagram of an example of a pairing procedure of a hearing assistance system like that shown in Fig. 1 ; Fig. 3 is a schematic illustration of the procedure of Fig. 2;

Figs. 4 and 5 are representations like Figs. 2 and 3, respectively, with another example of a pairing procedure being illustrated; and

Figs. 6 and 7 are representations like Figs. 2 and 3, with a still further example of a pairing procedure being illustrated. Fig. 1 is a block diagram of an example of a system comprising a first hearing assistance device 10 to be worn at one ear of a user, a second hearing assistance device 11 to be worn at the other ear of the user and an external device 40.

In the example of Fig. 1 , the hearing assistance devices 10, 11 are hearing aids comprising a microphone arrangement 12 for capturing audio signals from ambient sound, an audio signal processing unit 14 for processing the captured audio signals and an electro-acoustic output transducer (loudspeaker) 16 for stimulation the user's hearing according to the processed audio signals (these elements are shown in Fig. 1 only for the hearing aid 0). The hearing aids 10, 11 comprise a wireless interface 20 comprising an antenna 26 and a transceiver 28.

The interface 20 is provided for enabling wireless data exchange between the first hearing aid 10 and the second hearing aid 11 via a wireless link 30 which serves to realize a binaural hearing assistance system, allowing the hearing aids 10, 11 to exchange audio signals and/ or control data and status data, such as the present settings of the hearing aids 10, 11.

The interface 20 is also provided for data exchange via a wireless link 30 from an external device 40, for example for receiving an audio data stream from an external device 40 acting as an audio source, comprising a wireless interface 20 .

For example, the interface 20 may be adapted to operate in a frequency range of 0.38 GHz to 5.825 GHz, preferably at frequencies around 2.4 GHz in the ISM band. Typically, the interface 20 is a Bluetooth interface; alternatively, it may use another standard protocol or proprietary protocol. Preferably, the external data stream is an audio data stream which may be mono stream or a stereo stream; alternatively or in addition the external data stream may include text data.

The hearing aids 10, 11 also comprise a controller 38 for controlling operation of the hearing aids 10, 11 , with the controller 38 acting on the signal processing unit 14 and the transceiver 28, and a memory 36 for storing data required for operation of the hearing aid 10, 11 and data required for operation of the interface 20, such as pairing / network data.

While the binaural link between the hearing devices 10, 11 may be realized by the wireless interfaces 20 which are also used for the connection with the external device 40, the binaural link alternatively couid be realized by a separate interface using a different technology, such as an inductive link or a proprietary protocol. An example is shown in dashed lines in Fig. 1 , according to which the hearing aids 10, 11 in addition to the interface 20 comprise a second interface 8, including an antenna 22 and a transceiver 24, which is used for realizing the wireless data exchange between the first hearing aid 10 and the second hearing aid 1 via the wireless link 30 - rather than using the interface 20 to this end. For example, the second interface 18 may be designed to form part of a hearing instrument body area network (HIBAN) using an inductive link which may operate, for example, in a frequency range of 6.765 MHz to 13.567 MHz, such as at 10.6 MHz. However, rather than being implemented as an inductive link, the binaural wireless link 30 may be a far-field link requiring, such as a proprietary or standard digitally modulated link operating in the 2.4 GHz ISM band.

The first and second hearing assistance devices typically are ear level devices and preferably form a binaural hearing system. For example, the hearing assistance devices may be hearing aids, such as BTE (behind the ear), ITE (in the ear) or CIC (completely in the channel) hearing aids. Alternatively, the hearing assistance devices may be wireless headphones.

In general, the hearing assistance devices are not restricted to ear-level or body- worn devices: For example, according to one embodiment, the hearing assistance devices may be two or more wireless (room) loudspeaker devices.

The external device typically is an audio source (although it is also could be an audio sink) for providing an audio stream to the hearing assistance devices. For example, the external device may be an audio communication device, such as a mobile phone, a !andline phone or an internet phone device, or a TV-set, a personal computer, a tablet computer, a radio device or a media player. Alternatively, the external device may be an accessory device of a hearing assistance device, such as a wireless microphone, a hearing assistance device remote control or an audio streamer device.

An example of a first embodiment of a pairing procedure for a hearing assistance system like that of Fig. 1 is illustrated in Figs. 2 and 3, with Fig. 2 showing a sequence diagram and with Fig. 3 schematically illustrating the sequence steps of Fig. 2. According to the example of Fig. 2, the left ear hearing device 10 and the right ear hearing device 11 are paired upon interaction by the user of the hearing devices 10, 11 (pairing the two hearing assistance devices serves to introduce the devices to each other so that they know each other's identity and to enable the devices to securely exchange messages, if so desired). For example, the user may interact with the left ear hearing device 10 in order to cause the left ear hearing device 10 to send a pairing request message via the interface 20 to the right ear hearing device 11 , which, in turn, sends a pairing confirmation message via the interface 20 back to the left ear hearing device 10. The respective pairing information exchanged between the two hearing devices 10, 11 is stored in the memory 36 of the respective hearing device 10, 11.

Thereafter, the user may interact with the external device 40 in order to initiate pairing between the external device 40 and the left ear hearing device 10, whereupon the external device 40 transmits a corresponding pairing request message to the left ear hearing device 10 which, in turn, transmits a pairing confirmation message back to the external device 40 (typically, the device 10 may require, for security reasons, an additional user interaction with device 10 before confirming the pairing request in order prevent unwanted pairing). After successful pairing, the respective pairing information exchanged between the devices 40 and 10 is stored in the respective device 40, 10.

Thereupon, the left ear hearing device 10 transmits a remote pairing request message to the right ear hearing device 11 which causes the right ear hearing device 11 to transmit a pairing request to the external device 40 which, in turn, sends back a pairing confirmation message to the right ear hearing device 11. After successful pairing, the pairing information exchanged between the right ear hearing device 11 and the external device 40 is stored in the devices 11 and 40, thereby finalizing the pairing procedure.

After termination of the pairing procedure, both the left ear hearing device 10 and the right ear hearing device 11 are paired with the external device 40, thereby completing setup of a communication network.

The user interaction step with the external device 40 is indicated at "A1" in Figs. 2 and 3, the pairing action between the left ear hearing device 10 and the external device 40 is indicated at "B1", the transmission of the remote pairing request is indicated at "C1", and the pairing action of the right ear hearing device 11 and the external device 40 is indicated at "D1 "; further the user interaction with the left ear device 10 and the subsequent pairing between the devices 10 and 11 is indicated at "AO" in Fig. 2.

It is noted that the transmission of the remote pairing request message in step "C1" from the left ear device 10 to the right ear device also serves to transmit the information required by the right ear device 11 to initiate pairing with the externa! device 40 to the right ear device 11 , for example the identity of the external device 40.

In case that one of the pairing steps "ΒΓ or "D1" fails, the pairing action is retried until pairing is successful, or, if still no successful pairing is achieved, the pairing process is terminated and possibly existing partial pairing information on the left ear hearing device 10 is erased to ensure that either both or none of the hearing devices 10, 11 is paired with the external device 40.

According to a variant, the user may initiate pairing between the left ear hearing device 10 and external device 40 by interaction with the left ear hearing device 0, rather than with the external device 40, as indicated at "AT ¹ in Fig. 3.

According to a further variant, the pairing action "B1" between the left ear device 10 and the external device 40 may be carried out after the pairing action "D1" of the right ear device 11 and the external device 40.

According to a still further variant, the hearing assistance devices 10, 11 may be paired already at the manufacturer, so that the manual pairing action of step AO can be omitted.

It is to be understood that in the example of Figs. 2 and 3, as well as in the other examples, of course the roles of the left ear device 10 and the right ear device 11 may be interchanged. Functionally, one of the hearing assistance devices may be considered as a "first device", whereas the other one may be considered as a "second device".

An example of a second embodiment of the invention is illustrated in Figs. 4 and 5, wherein, in contrast to the embodiment illustrated in Figs. 2 and 3, the left ear hearing device 10 transmits a remote pairing request message to the external device 40 rather than to the right ear hearing device 11 , in order to make the external device 40 initiate pairing with the right ear hearing device 11.

In the sequence diagram of Fig. 4, the pairing action of the left ear device 10 and the right ear device 11 shown at the beginning of the sequence diagram of Fig. 2 (indicated at "AO") has been omitted, so that at the beginning of the sequence diagram of Fig, 4 the right ear device 11 and the left ear device 10 may have been already paired. However, since the embodiment of Fig. 2 does not require a binaural data exchange, the pairing between the left ear device 10 and the right ear device 11 may be omitted.

On the other hand, if the two hearing devices were paired, the left hearing device can provide information to the external device, to facilitate an authentication of the pairing request to the right hearing device. That is, the external device can prove with the information provided by the left hearing device to the external device that it is authorized by the left device to perform a pairing with the right device. Similar to the first embodiment, the end user may have to confirm the pairing on the left hearing device, whereupon the left hearing device provides this authorization information.

As in the example of Fig. 2, the user interacts with the external device 40 in order to pair the external device 40 and the left ear device 10 (as also indicated in Figs. 4 and 5 by steps "A2" and "B2")- However, in contrast to the example of Fig. 2, the left ear hearing device 10, upon successful pairing with the external device 40, transmits a remote pairing request message to the external device 40, rather than to the right ear device 11. The remote pairing request message causes the external device 40 to initiate pairing with the right ear device 11 by transmitting a pairing request message to the right ear hearing device 11 which, upon receipt of the pairing request message, sends a pairing confirmation message back to the external device 40. After successful pairing, the pairing information exchanged between the external device 40 and the right ear device 11 are stored in the external device 40 and the right ear device 11 , respectively, thereby finalizing pairing of both the left ear device 10 and the right ear device 1 with the external device 40.

The transmission of the remote pairing request message to the external device 40 is indicated at "C2" in Figs. 4 and 5, and the pairing action between the right ear device 11 and the external device 40 is indicated at "D2".

Preferably, after successful pairing of the right ear device 11 with the external device 40, the right ear device 11 , or alternatively the external device 40, transmits a pairing success notification message to the left ear device 10 in order to notify the left ear device 10 that the right ear device 11 has been successfully paired with the external device 40. Preferably, if one of the pairing steps B2 and D2 fails, it is retried until successful pairing is achieved, or otherwise the pairing process is aborted, with any existing partial pairing information on the left ear device 11 or right ear device 10 being erased in order to ensure that either both or none of the hearing devices 10, 11 are paired with the external device 40.

An example of a third embodiment of the invention is illustrated in Figs. 6 and 7, wherein one of the hearing assistance devices promotes pairing of the other hearing assistance device with the externa! device by presenting, in a pairing procedure with the external device, itself as the other hearing assistance device, rather than transmitting a pairing initialization command to the other hearing assistance device (as in the embodiment of Figs. 2 and 3) or to the external device (as in the embodiment of Figs. 4 and 5).

First, a binaural link is established between the left hearing device 10 and the right hearing device 11 (this step is not shown in the sequence diagram of Fig. 6), for example by pairing the devices 10, 11 as shown in Fig. 2 (step "AO" in Fig. 2), with the interfaces 20 being used for such binaural communication link. As next step, the user may interact with the external device 40 in order to initiate pairing of the external device 40 and the left ear device 10, with the external device 40 transmitting a pairing request message to the left ear device 10 and with the left ear device 10 sending back a pairing confirmation message to the external device 40 (as indicated at "B3" in Figs. 6 and 7). These pairing steps correspond to the pairing steps A1 and B1 of Fig. 2.

As a next step, the left ear device 10 transmits an "ignore pairing" request to the right ear device 11 via the binaural link, with such pairing disable command causing the right ear device 11 to disregard any subsequent pairing data and pairing commands received via the interface 20 (this step is indicated at "C3"). Such transmission of a pairing disable command by the left ear device 10 may be triggered by successful pairing of the left ear device 10 with the external device 40.

Thereafter, the left ear device 10 pairs with the external device 40 a second time, this time presenting itself, however, not as the left ear device 10 as in step B3, but as the right ear device 1 by using data required for pairing of the right ear device 11 ; the left ear device 10 may have received such pairing data of the right ear device 11 via the binaural link. Typically, this information is exchanged during the initial binaural pairing AO. Alternatively, the information could be exchanged at the time of the pairing with the external device 40 by using the binaural link.

Rather than using the network interfaces 20 for such pairing data exchange, a separate binaural wireless interface 18, as shown in Fig, 1 , if present, may be used. According to a further alternative option, the pairing information may be exchanged via a wired interface, for example in a pairing configuration step during manufacturing of the hearing assistance devices 10, 11.

In order to initiate such pairing of the left ear device 10 presenting itself as the right ear device 11 , the left ear device 10 transmits a pairing request message to the external device 40, using the right ear device data, with the external device 40 sending back a pairing confirmation message to the left ear device 10 (see step "D3").

In order to complete pairing of the right ear device 11 with the external device 40, the left ear device 10 transmits the data resulting from pairing with the external device 40, i.e. the pairing data established during the pairing procedure of the left ear device 10 when presenting itself as the right ear device 1 to the external device 40, to the right ear device 11 (see step "E4").

After having finalized step E3, both hearing assistance devices 10, 11 are paired with the external device 40.

The transmission of the pairing information of the external device 40 from the left ear device 10 the right ear device 11 (step E3) may be carried out using the protocol which is also used for the data exchange with the external device 40; alternatively, a proprietary link may be used. The transmission of the pairing data may be secured against eavesdropping.

Preferably, the right ear device 11 , after successful pairing with the external device 40, transmits a pairing success notification message to the left ear device 10 in order to notify the left ear device 10 that the right ear device 11 has been successfully paired with the external device 40. Preferably, if one of the pairing steps B3 and D3 fails, it is retried until successful pairing is achieved, or otherwise the pairing process is aborted, with any existing partial pairing information on the left ear device 11 being erased in order to ensure that either both or none of the hearing devices 10, 11 are paired with the external device 40.

It is to be understood that, as an alternative, the pairing between the left ear device 10 and the external device 40 (cf. step B3) may be carried out after step D3 wherein the left ear device 10, presenting itself as the right ear device 11 , pairs with the external device 40. As mentioned above, the right ear device 11 enters an "ignore pairing" mode by receiving an ignore pairing request from the left ear device 10. It may exit such "ignore pairing" mode in different ways.

For example, the message communicating the pairing data resulting from the pairing of the left ear device 10, when presenting itself as the right ear device 11 , with the external device 40, to the right ear device 11 , may trigger the exit from the "ignore pairing" mode.

Alternatively, the above mentioned explicit pairing success notification message received from the left ear device 10 exchange may cause the right ear device 11 to exit the "ignore pairing" mode. According to a further alternative, the right ear device 11 may exit the "ignore pairing" mode after elapse of a certain time, i.e. in a timer-based manner.

Generally, the described pairing principles may be applied not only to binaural systems with two hearing assistance devices, but also to systems comprising more than two hearing assistance devices. In such case, the described pairing principies may be applied repeatedly to different ones of the plurality of hearing assistance devices to be paired, i.e. different ones of the plurality of hearing assistance devices subsequently may take the role of the second hearing assistance device is which paired with the external device with the help of the first hearing assistance device (for example, the role of the first hearing assistance device may be always taken by the same device). Such option of pairing more than two hearing assistance devices with an externa! device is particularly interesting in case that the hearing assistance devices are wireless loudspeakers.