JP6599131B2 - A new way to wirelessly transmit digital audio - Google Patents

Description

  A novel method for wirelessly communicating data with different priorities is provided, for example, in compliance with the Bluetooth Low Energy (LE) standard. Also provided is a novel hearing device configured to be suitable for wireless communication in a novel manner.

The Bluetooth LE defined in the Bluetooth core specification 4.1 or earlier does not allow audio transmission. There are some limitations to the protocol as it is defined, which means that audio transmission is not feasible without changing some protocol layers.
-The nature of the L2CAP channel defined for LE, which defines a best-effort data transmission method that does not use timeout or flush when transmitting, is also the real-time audio It means that service is almost impossible.
The lack of real time transmission means that stereo synchronization between two paired audio syncs (such as hearing aids) is almost impossible.
-Packet size means that the overhead for transmitting the data rate required for audio (typically 32 to 48 kbit / s) is very large.

  It is the purpose of the novel method and hearing device to overcome the above-mentioned drawbacks.

A novel method for wirelessly communicating a data set is provided that includes:
a) transmitting a first data set of a first data category for receiving from a transmitting device to a receiving device;
b) resending the first data set if there is no acknowledgment of receipt from the receiving device.
c) If there is an acknowledgment of reception from the receiving device, if there is no acknowledgment, when the transmitting device and the receiving device are connected for retransmission, for example, a first data set of the first data category Transmitting from the transmitting device to the receiving device a second data set of a second data category different from the first data category within the same connection event that was transmitted.

In addition, a novel method for wirelessly communicating data having different priorities is provided, including:
a) transmitting a first data set of a first priority for receiving from a transmitting device to a receiving device;
b) resending the first data set of the first priority if there is no acknowledgment of receipt from the receiving device.
c) If there is an acknowledgment of reception from the receiving device, if there is no acknowledgment, the transmitting device and the receiving device have a second priority lower than the first priority when connected for retransmission. Transmitting the second data set from the transmitting device to the receiving device;

  The first data category may include an audio data set.

  The second data category consists of various control data such as start, stop, codec negotiation, and / or the like according to the Bluetooth LE standard protocol as defined in the Bluetooth Core Specification 4.1 or earlier versions, and / or Or it may include data from other devices, for example devices with sensors such as environmental sensors such as temperature sensors.

  The first data set may be an audio data set. The audio data set includes digital audio signal values, such as a series of discrete time and discrete amplitude digital audio signal values, and the series of discrete time and discrete amplitude digital audio signal values is an analog audio signal value. The continuous time and continuous amplitude values are represented, and the analog audio signal can be converted to sound. In other words, as is well known in the streaming audio art, an audio data set contains digital data that is intended to be converted to sound at some point.

  Preferably, to ensure high fidelity or at least acceptable quality of sound generated based on the transmitted audio data set, the audio data set has a high priority and a lower priority Ensure that the audio data set is transmitted before transmitting any other type of data set with a degree.

  A data set, including an audio data set, can be a data packet having two types of data: control information and data. Data is also known as payload or payload data. The control information provides information data required by the network to deliver the data, ie, the payload, to the intended receiving device, eg, source and destination device addresses, error detection codes, and sequence control information. Typically, control information is found in the header and trailer of the packet with payload data in between.

The method may further include:
d) Signaling from the transmitting device to the receiving device as to whether a data set having the second priority is waiting for transmission to the receiving device.
e) If there is no data set with the second priority waiting for transmission to the receiving device, between the transmitting device and the receiving device for transmission of the second data set with the second priority. To stop establishing the connection.

  Information regarding whether a data set having a second priority is waiting for transmission to the receiving device may be encoded into a single data byte, such as a single data bit.

  The method may be compliant with a Bluetooth Low Energy standard such as Bluetooth Core Specification 4.1 or earlier, and preferably the transmission of the audio data set is within a continuous connection event. To be implemented.

  The method may be used, for example, for audio and music audio streaming, in a manner compliant with the Bluetooth Low Energy standard, such as the Bluetooth Core Specification 4.1 or earlier.

  The method may further include assigning an L2CAP channel to the transmission of the audio data set, eg assigning one L2CAP channel to control data associated with the audio data set and / or 1 One L2CAP channel may be assigned to the first audio data set and another L2CAP channel may be assigned to the second audio data set if possible.

The following three fixed L2CAP channels may be allocated for audio transmission.
1) Control data (start, stop, codec negotiation, etc.)
2) Left audio data 3) Right audio data

  In a device capable of receiving one audio stream (left or right), for example a hearing aid, only channels 1) and 2) or channels 1) and 3) will be used for that device. In a device with an integrated stereo function, such as a stereo headset, all three channels are used. The audio data set may be unidirectional or bidirectional depending on the field of application, and the control data channel should allow negotiation on that point.

For example, the connection configuration may be performed by the following procedure.
1. The receiving device informs through a unique UUID that it can receive priority-enabled flashable L2CAP (PFL2CAP: prioritized and flushable L2CAP) data.
2. The transmitting device finds the receiving device, connects to the receiving device, and queries the PFL2CAP service for its function.
3. The receiving device responds with a PFL2CAP configuration. For audio, for example, this includes which codec the receiving device provides and what content the receiving device intends to receive on which L2CAP channel and at which priority, eg (channel 127, high priority, left side) Audio), (channel 128, high priority, right audio), and (channel 129, low priority, audio control information).
4). The sending device acknowledges the reception by sending additional information about the data, such as information about content, codec and frame size, flash timeout, etc.
5. Both the sending device and the receiving device set up a new L2CAP channel, prepare an audio stream, and adjust the connection rate to match the product of the specified frame rate times the number of retransmissions.

For example, the operation of the transmission apparatus while streaming audio may include the following contents.
1. The sender controller host begins processing the audio stream and processes the first audio frame to be encoded and queued for immediate transmission on the specified L2CAP channel (s). . The host then proceeds to process the next audio frame.
2. At the same time, the control layer tries to send the packets in priority order. As soon as the transmission is successful, the control layer notifies the success and requests the next packet from the host. When a packet is flushed due to a timeout, the control layer notifies the failure and still requests the next packet.
3. Audio control information from the host, eg volume change, is queued in the designated L2CAP channel. The controller transmits the packet when no transmission packet is waiting with a higher priority.

  The method further determines that the number of retransmission attempts for the same audio data set is less than a predetermined maximum value, eg, equal to 2, if there is no acknowledgment of reception from the receiving device of the audio data set. The condition may include retransmission of the audio data set.

  The number of retransmission attempts of one or more types of data may not be limited, i.e. no maximum value is assigned to one or more types of data, or in other words one. Or, the maximum value assigned to a plurality of types of data is infinite, for example, 0xFFFF.

  Different types of data may have different predetermined maximum values for retransmission attempts, for example, an audio data set can have a maximum value of 2, while lower than the priority of the audio data set Maximum value of data set with priority.

  For example, the novel method can implement an L2CAP flush timeout, which is also defined in the Bluetooth Basic Rate (BR) L2CAP channel. Preferably, this timeout corresponds to two connection events for the channel carrying the audio data after the data has been posted via HCI (ie, allowing a first retry event for L2CAP audio). On the other hand, it remains at 0xFFFF for the other channels.

  On a typical link, packets can be lost at a rate unsuitable for audio. Thus, preferably retransmission is possible, preferably on a different channel. Therefore, the MD function of Bluetooth LE cannot be used for retransmission. Therefore, an audio data set with a flash timeout should simply be tried once within the connection interval. In order to allow retransmission, the connection interval must be half the audio frame size, so if the audio frame is 10 ms, the connection interval should be 5 ms. This is facilitated using existing link layer control packets.

  The MD function may be used to send low priority data within the same connection event, but the receiving device may not accept the MD bit, for example, the hearing aid will not accept the MD bit.

  In order to reduce the power consumption of the receiving device, the transmitting device indicates that there is low priority data waiting, whether or not it transmits data in the same connection event after the high priority data. Therefore, the MD bit may be set in the high priority packet. If there is no low priority data waiting, the MD bit is reset. This allows the receiving device to skip connection events without data between successful transmissions of the high priority audio data set in response to the value of the received MD bit. Similarly, a transmitting device may skip connection events with no data waiting during audio streaming to save power and / or improve interoperability with other wireless services. Is possible.

  Note that when transmitting a non-audio data set, if there is no L2CAP flush timeout, the link will be occupied until it is acknowledged for the data. This rarely causes dropouts in the audio, which must be dealt with by packet loss concealment on the receiving side, as disclosed for example in EP 2605547A1.

  The method further includes between at least two different receiving devices connected to receive different audio data sets from the transmitting device to at least one receiving device configured to receive the audio data sets. Transmission of synchronization data including timing information related to the transmission delay difference may be included.

  The determination of the synchronization data may be based on a ping transmission from the transmitting device to at least two different receiving devices, for example a ping transmission using an L2CAP control channel.

  Preferably, during stereo audio streaming, the transmitting device communicates the time offset between the links to the preceding receiving device in the link, thereby delaying the received audio accordingly, so that two stereo Channels can be properly synchronized. The time offset can be determined using a network latency measurement that pings via the control channel. This ping allows the sending host to calculate the time offset.

  Stereo audio streaming can also be implemented using a single link. For example, during stereo audio streaming to headphones, both the left L2CAP channel and the right L2CAP channel may be transmitted using the same link, thereby keeping both the receiver and transmitter simple. Is done. Since headphones can withstand higher wireless duty cycles, the MD function of Bluetooth LE may be utilized for this purpose. In this way, the same connection event can carry information about both the left and right channels, and the packet structure can be kept the same as in the mono or dual sync case. This simplifies the mounting on both sides. This is because it is necessary to change only the connection handle for audio on the transmission host side as compared with the case of dual sync.

  The following table outlines the number of requested bytes required to hold an audio data set given a certain audio frame size in ms. These values are for audio streams that flow at 48 kbit / s. For an audio stream of 32 kbit / s, this request is 2/3.

  To minimize overhead, the method or controller that implements L2CAP audio preferably matches the LL MTU size to the sum of the L2CAP MTU plus the header and MIC so that it can accommodate long packets, And preferably equal to the required payload size.

  Advantageously, the novel method facilitates the transmission of audio data sets utilizing Bluetooth LE by making limited use of Bluetooth LE controls and link layer extensions, eg, Operations related to security and link setup are performed as specified in the Bluetooth core specification.

  A hearing device is also provided having a communication controller adapted to operate according to the novel method of any of the appended claims.

  Hearing aids include BTE, RIE, ITE, ITC, CIC and other hearing aids, binaural hearing aids, ear-hook type, in-ear type, on-ear type, over-ear type, behind-neck type, helmet type, head guard A headset such as a model, headphones, earphones, ear defenders, ear muffs, etc. may be used.

Preferably, the communication controller is configured to be suitable for audio transmission and / or reception of audio using Bluetooth LE L2CAP.
-Supports L2CAP flush timeout = 2-Supports prioritized L2CAP traffic-Configures to support LL packet sizes up to 120 bytes depending on bitrate and audio frame size selection Is done.

  Accordingly, a novel hearing aid is provided that can implement wireless communication in accordance with the Bluetooth LE standard protocol.

New hearing aids
The input transducer configured to output the audio signal based on the signal representing the sound given thereto, and the hearing loss of the hearing aid user are compensated, and the audio signal compensated for the hearing loss is output. For example, the hearing aid may be configured such that the loudness of a given signal as perceived by a normal hearing person is such that the loudness of a signal compensated for hearing loss is perceived by a user. Handset, embedded type, which can be aimed at recovering the loudness of the sound so that it almost matches the loudness, and is configured to output an audio output signal based on the audio signal compensated for hearing loss An output transducer, such as a transducer, that allows the human auditory system to receive the auditory output signal so that the user can hear the sound An output transducer, and it may include a communication controller.

  A transducer is a device that converts a signal applied to a transducer in one form of energy into an output signal that takes the form of another corresponding energy.

  The input transducer can include a microphone, which converts the acoustic signal applied to the microphone into a corresponding analog audio signal whose instantaneous voltage continuously varies with the sound pressure of the acoustic signal. To do.

  The input transducer may comprise a telecoil. The telecoil converts a magnetic field that fluctuates in the telecoil into a corresponding analog audio signal that fluctuates in an instantaneous voltage continuously with a magnetic field strength that fluctuates in the telecoil. Telecoils can be used, for example, to hear audio from speakers talking to multiple people in public places such as churches, public halls, theaters, movie theaters, or through loudspeakers in stations, airports, shopping malls, etc. It can be used to increase the signal to noise ratio. Voice from the speaker is converted to a magnetic field using an inductive loop system (also called a “hearing loop”), and a telecoil is used to magnetically pick up the magnetically transmitted voice signal.

  The input transducer may further comprise at least two spaced microphones and a beamformer configured to combine the microphone output signals of the at least two spaced microphones into a directional microphone signal.

  The input transducer includes one or more microphones, a telecoil, and a switch for selecting, for example, an omnidirectional microphone signal, or a directional microphone signal, or a telecoil signal, alone or in any combination, as an audio signal. May be provided.

  Typically, an analog audio signal is converted into a corresponding digital audio signal in an analog-to-digital converter, whereby the amplitude of the analog audio signal is expressed in binary, thereby enabling digital signal processing. It will be suitable. In this way, a discrete time and discrete amplitude digital audio signal in the form of a series of digital values represents a continuous time and continuous amplitude analog audio signal.

  Throughout this disclosure, an “audio signal” may be used to identify any analog or digital signal that forms part of the signal path from the output of the input transducer to the input of the hearing loss processor.

  Throughout this disclosure, “hearing loss compensated audio signal” means any part of the signal path from the hearing loss processor output, possibly through a digital-to-analog converter, to the output transducer input. Can be used to identify analog or digital signals.

  The hearing aid can comprise a transceiver with both a wireless transmitter and a wireless receiver. The transmitter and receiver may share a common circuit and / or a single housing. Alternatively, the transmitter and receiver may not share circuitry, and the wireless communication unit may comprise separate devices with the transmitter and receiver, respectively.

  Hearing aids advantageously use, for example, the Bluetooth LE standard protocol for two hearing aids to digitally exchange data such as audio signals, control data such as signal processing parameters, signal processing program identifiers, etc. May be incorporated into binaural hearing aid systems that are interconnected and optionally interconnected with other devices such as tablet computers, smartphones (eg IPphone, Android phones, Windows phones, etc.), handheld devices such as remote controls .

Typically, only a limited amount of power is available from the hearing aid power supply. For example, power is typically supplied from a conventional ZnO ₂ battery in a hearing aid.

  When designing hearing aids, size and power consumption are important considerations.

  Signal processing in the new hearing aid may be performed by dedicated hardware, may be performed by one or more signal processors, or may be performed by dedicated hardware and one or more signal processors. You may implement in the combination of these.

  Similarly, operation of the communication controller may be performed by dedicated hardware, may be performed by one or more processors, or in combination of dedicated hardware and one or more processors. You may implement.

  As used herein, the terms “processor”, “signal processor”, “controller”, “system”, etc. refer to CPU, either hardware, a combination of hardware and software, software, or running software. Point to the entity.

  For example, “processor”, “signal processor”, “controller”, “system”, and the like are not limited to such, but are executed on a processor, processor, object, executable, thread of execution, And / or a program.

  By way of example, the terms “processor”, “signal processor”, “controller”, “system”, etc. refer to both applications running on the processor and hardware processors. One or more “processors”, “signal processors”, “controllers”, “systems”, etc., or any combination thereof, may exist within a thread of process and / or execution, and Multiple "processors", "signal processors", "controllers", "systems", etc., or any combination thereof, may be combined on one hardware processor, possibly in combination with other hardware circuits And / or may be distributed among two or more hardware processors, possibly in combination with other hardware circuits.

  A processor (or similar terminology) may also be any component capable of performing signal processing, or any combination of such components. For example, the signal processor may be an ASIC processor, FPGA processor, general purpose processor, microprocessor, circuit component, or integrated circuit.

  In the following, the novel method and hearing aid will be described in more detail with reference to the drawings.

FIG. 1 schematically illustrates a binaural hearing aid system that receives audio streaming from a smartphone according to a novel method. FIG. 2 schematically illustrates an example of transmitting an audio data set according to a novel method. FIG. 6 schematically illustrates another example of transmitting an audio data set according to a novel method. FIG. 6 schematically illustrates another example of transmitting an audio data set according to a novel method. FIG. 6 schematically illustrates another example of transmitting an audio data set according to a novel method. FIG. 6 schematically illustrates another example of transmitting an audio data set according to a novel method. FIG. 6 schematically illustrates another example of transmitting an audio data set according to a novel method. 2 is a flowchart of an example of a novel method. 6 is a flow diagram of another example of a novel method. 6 is a flow diagram of another example of a novel method. 6 is a flow diagram of another example of a novel method.

  In the following, various examples of novel methods and hearing devices are presented. However, the novel methods and hearing devices described in the appended claims can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein.

  It should be noted that the accompanying drawings are schematic and simplified for clarity, only show details essential to understanding the novel method and hearing aid, and other details are excluded.

  Like reference numbers refer to like elements throughout. Therefore, the same elements will not be described in detail in the description of each drawing.

  FIG. 1 schematically shows a binaural hearing aid system comprising a left ear hearing aid 10L and a right ear hearing aid 10R, where the left ear hearing aid 10L and the right ear hearing aid 10R are respectively a smartphone or a mobile phone, an audio-compatible tablet, a cordless phone, a television receiver. A wireless communication unit is provided so that it can be connected to another audio-compatible communication device such as a wireless device. In the present embodiment, the left ear hearing aid 10L and the right ear hearing aid 10R are connected to the smartphone 50 via the corresponding wireless communication links 12L and 12R, respectively. Those skilled in the art will appreciate that in other embodiments of the system where the right hearing aid 10R is optional, the binaural hearing aid system may comprise only a single hearing aid, such as 10L.

  A unique ID identifies every device in the binaural hearing aid system. The illustrated binaural hearing aid system is configured to generally operate in accordance with, for example, Bluetooth Low Energy (Bluetooth LE) corresponding to Bluetooth Core Specification Version 4.1. Accordingly, the illustrated binaural hearing aid system is configured to operate in the 2.4 GHz industrial scientific medical (ISM) band according to Bluetooth LE and includes 80 frequency channels with a 1 MHz bandwidth. However, as will be described in more detail below, the Bluetooth LE controller of each of the left and right ear hearing aids 10L and 10R and the smart phone 50 wireless communication unit does not provide real-time audio communication over each wireless communication link 12L, 12R. Modified to allow data set transmission.

The left hearing aid 10L and the optional right hearing aid 10R may be substantially the same and can be expected for the unique ID described above, so the following description of the characteristics of the left hearing aid 10L is for the right hearing aid 10R. Is also true. The left hearing aid 10L may include a ZnO ₂ battery (not shown) connected to supply power to the hearing aid circuit 14. The left hearing aid 10L includes an input transducer in the form of a microphone 16. When the left hearing aid 10L is operating, the microphone 16 outputs an analog or digital audio signal based on an acoustic signal that reaches the microphone 16. When the microphone 16 outputs an analog audio signal, the hearing aid circuit 14 converts the analog audio signal into a corresponding digital audio signal so that it can be processed digitally within the hearing aid circuit 14. A converter (not shown) may be provided. Specifically, it may be provided in a hearing loss processor 24L configured to compensate for the hearing loss of the user of the left hearing aid 10L. Preferably, the hearing loss processor 24L comprises a dynamic range compressor as is well known in the art by compensating for frequency dependent loss of the user's dynamic range, often referred to in the art as a supplementary phenomenon. Therefore, the hearing loss processor 24L outputs the audio signal compensated for hearing loss to the loudspeaker or receiver 32. The loudspeaker or receiver 32 converts the audio signal compensated for hearing loss into a corresponding acoustic signal and sends it to the user's eardrum. Therefore, the user can hear the sound that reaches the microphone but is compensated for the individual hearing loss of the user. In the hearing aid, the magnitude of the sound of the signal compensated for hearing loss perceived by the user wearing the hearing aid 10 is the magnitude of the sound of the acoustic signal reaching the microphone 16 as perceived by a listener having normal hearing. You may be comprised so that the loudness of sound may be regained so that it may correspond to this.

  The hearing aid circuit 14 further includes a wireless communication unit comprising a radio unit or circuit 34L configured to wirelessly communicate with the smartphone 50. The wireless communication unit comprises a Bluetooth LE controller 26L that performs various communication protocol related tasks and possibly other tasks. The operation of the left hearing aid 10L can be controlled by a suitable operating system. The operating system manages the hearing aid hardware and software resources, including, for example, the hearing loss processor 24L and other possible processors and associated signal processing algorithms, wireless communication units, some memory resources, etc. It may be configured. The operating system may schedule tasks so that hearing aid resources can be used efficiently, and cost, including power consumption, processor time, storage location, wireless transmission, and other resources. Accounting software may be included.

  The operating system controls the radio circuit 34L to perform wireless communication with the smartphone 50 in accordance with the Bluetooth LE protocol that is audio-enabled by being modified. In connection with bi-directional data communication between devices based on the modified Bluetooth LE protocol, the smartphone 50 can operate as a master device and the left hearing aid 10L may operate as a slave.

  The smartphone 50 includes a radio unit or radio circuit 54 configured to wirelessly communicate with a corresponding radio unit or radio circuit 34L of the left hearing aid 10L. The smartphone 50 also includes a wireless communication unit, which includes a Bluetooth LE controller 56 that performs various communication protocol related tasks according to a modified Bluetooth LE protocol and possibly other tasks. Data packets or data sets to be transmitted over the wireless communication link 12L are supplied to the radio circuit 54 by the Bluetooth LE controller 56. Data packets received by the radio unit or circuit 54 via the RF antenna 53 are sent to the Bluetooth LE controller 56 for further data processing. As is well known in the mobile phone art, those skilled in the art will appreciate that the smartphone 50 typically includes a number of additional hardware and software resources in addition to those shown schematically. .

  FIG. 2 shows, for example, data sets having different priorities between the left ear hearing aid 10L and the smartphone 50 described above, for example, with the smartphone 50 configured as a master and the hearing aid 10L configured as a slave. FIG. 2 is a first timing diagram 200 illustrating a novel method for wireless communication.

  FIG. 2 shows that there is less coherent electromagnetic noise in the associated data channel, so the transmission of each data packet or data set from the transmitting device was successful in the first transmission attempt, and therefore requires retransmission Fig. 2 shows the operating state of a wireless communication link (12L in Fig. 1) without a link.

  Successive connection events on the wireless communication link are indicated by Ci1, Ci2, Ci3, etc. along the time axis t. One skilled in the art will appreciate that the adjacent connection events shown, such as Ci1 and Ci2, can be separated by a fairly long sleep period, eg, up to 4 seconds, according to the Bluetooth LE protocol. During such a sleep period, both the radio circuit 34L of the left hearing aid 10L and the radio circuit 54 of the smartphone 50 can be powered down to reduce power consumption. A connection event may have a duration or connection interval between 5 ms and 10 ms. The connection interval for each connection event is preferably selected to be one half of the selected audio frame size of the audio data set transmitted over the wireless communication link.

  Table 2 below schematically illustrates the number of bytes required to hold audio data given a specific audio frame size in milliseconds. The listed values are for audio streams that flow at 48 kbit / s. For an audio stream of 32 kbit / s, this request is 2/3.

  Two types of data with different priorities are transmitted over the wireless communication link, as shown in FIG. 2 by data packets 205, 210, 215 or data set symbols “A” and “D”. The data packets indicated by A1 and A2 have first priority data, and the data packet D has a second priority lower than the first priority. In the illustrated example, a first priority or high priority data packet 205, 215 includes an audio data set, and a lower priority data packet 210 is a Bluetooth core specification 4.1 or Contains various control data such as start, stop, codec negotiation, etc., compliant with the Bluetooth LE protocol from earlier versions. The data structure of each of the high priority data packets A 1, A 2 is shown by data packet 230. High priority data packet 230 includes a header section 235 that may have two bytes. The high priority data packet 230 further includes the payload data 240 described above that may include between 60 and 120 bytes of audio data depending on the audio frame size. The 60-byte payload data size is approximately 1.5 ms long in each high priority data packet, which fits in the time window of the corresponding connection event. The header section 235 preferably includes a so-called more data (MD) field or bit, indicated by the symbol “1”. This MD field indicates whether there is a low priority data packet D waiting. When there is a low priority data packet D in the waiting state, the Bluetooth LE controller 56 of the transmitting device sets this MD bit, and when there is no low priority data packet D in the waiting state, the MD bit is set to “ Reset to “0”. The Bluetooth LE controller 56 preferably sets the MD bit regardless of whether the transmitting device actually transmits the low priority data packet D within the same connection event Ci1 after the high priority data packet A1. Configured to set or reset. This function allows the receiving device to skip a connection event that does not have a low priority data packet D in a waiting state during the connection event of a successful high priority data packet by examining the MD bit, or It becomes possible to lose.

  The low priority data packet D may have a length of 37 bytes. When the transmission sequence of the high priority data packet and the low priority data packet by the transmission apparatus is shown, the first high priority data packet A1 is transmitted first. Thereafter, the operation mode of the radio circuit 54 of the transmission device is reversed from the transmission mode to the reception mode during a short pause of, for example, a length of about 150 μs. Therefore, the radio circuit 54 of the transmission device includes a Bluetooth transceiver. In the receive mode, the transmitter radio circuit 54 monitors the communication link and ensures that the high priority data packet A1 transmitted from the receiver, i.e., the left ear hearing aid 10L in the current situation, is correctly received. Listen for an acknowledgment received signal to indicate. The receipt of this acknowledgment signal or packet is indicated by the packet or signal 207 labeled “Ack”. Since the MD bit discussed above in the header 235 of the high priority data packet A1 is set to “1”, the low priority data packet D is waiting and waiting for transmission. Accordingly, the transmitting device transmits a low priority data packet D210 that is in a waiting state as shown, and after another short pause, a second acknowledgment signal or packet 209 is received as shown.

  At this point, the Bluetooth LE controller 26L of the receiving device has reliably received both the high priority data packet A1 and the low priority data packet D. Accordingly, the Bluetooth LE controller 26L can safely abandon or skip the subsequent connection event Ci2, which is otherwise used for retransmission of the high priority data packet A1, which will be described in more detail below. . Thus, the wireless transceiver of the receiving device is not turned on during the second connection event Ci2, thereby saving considerable power compared to receiving and transmitting data packets.

  During the third connection event Ci3, a new high priority data packet A2 (215) is transmitted to the receiving device, which then returns an acknowledgment packet 211 labeled "Ack" to the transmitting device. To acknowledge positive receipt. In the header 235 of the second high priority data packet A2, the MD bit can be set to “0” to indicate that no low priority data packet D is waiting. At this point, the receiving device's Bluetooth LE controller 26L has received the high-priority data packet A2 reliably, and by checking the MD bit in the header of the packet A2, the low-priority data packet D in the waiting state is received. It can be concluded that there is no. Therefore, the Bluetooth LE controller 26L consequently gives up or skips the subsequent connection event Ci4 (not shown).

  FIG. 3 shows another exemplary timing diagram 300 illustrating a novel method for wirelessly communicating data sets having different priorities. FIG. 3 illustrates an occasional failure to transmit individual data packets or data sets from a transmitter to a receiver due to some coherent electromagnetic noise in the associated data channel, eg, for the wireless communication link 12L of FIG. Indicates the operating state.

  As described above in connection with FIG. 2, successive connection events of the wireless communication link are indicated by Ci1, Ci2, Ci3, Ci4, etc. along the time axis t. Those skilled in the art will appreciate that the adjacent connection events shown, such as Ci1 and Ci2, can be separated according to the Bluetooth LE protocol by a fairly long sleep period or inactivity period, eg, up to 4 seconds.

  In FIG. 3, the transmission sequence of the high priority data packets A1 and A2 and the low priority data packet D by the transmission device starts from the transmission of the first high priority audio data packet A1. The transmitter then switches operation to the reception mode described above and monitors the communication link for a received signal or package acknowledgment transmitted by the receiver, ie, the left ear hearing aid 10L. In the illustrated communication sequence, transmission of the high priority data packet A1 within the connection event Ci1 is successful, and the receiving apparatus transmits an acknowledgment signal or packet Ack. There is no low-priority data packet D waiting and waiting for transmission, so in the header of the high-priority data packet A1, the above-mentioned MD bit is “MD” in the data packet A1 of FIG. As shown by “= 0”, it is set to “0”.

  Since high priority data is received and there is no low priority data packet D waiting, the receiving device skips the next connection event Ci2, thereby reducing power consumption in the receiving device.

  Within the third connection event Ci3, the high-priority data packet A2 is transmitted for the first time, with limited success. The receiving device receives the data packet, but a transmission error is detected, for example in the CRC, and the receiving device sends an acknowledgment signal or data packet “Nack”, possibly in the same connection event Ci3. The above MD bit is set to “1” to request retransmission of the data packet. Therefore, the data packet A2 is retransmitted in the same connection event Ci3, but in this example, a transmission error is detected in the receiving device, and the same result as the previous time is obtained. Optionally, to save power, the receiving device does not transmit a second “Nack” signal or packet.

  Thereafter, a first retransmission within the subsequent connection event Ci4 is performed, this time the receiving device has successfully received the data packet A2, so that the receiving device sends an acknowledgment signal or packet to the transmitting device. To do. As indicated by “MD = 0” in data packet A2 of FIG. 3, there is no low priority data packet D in a wait state.

  If the transmitted data packet is lost, the receiver does not send any signal, such as a “Nack” signal, and if there is no signal from the receiver, the connection event is preferably terminated to save power. Thus, preferably, no retransmissions occur within the same connection event that the first transmission of the data packet was performed.

  FIG. 4 shows another exemplary timing diagram 400 illustrating a novel method for wirelessly communicating data sets having different priorities. In this case, the maximum number of retransmissions of high priority data packets within a new connection event is set to 1. FIG. 4 may sometimes fail to transmit individual data packets or data sets from the transmitting device to the receiving device due to some coherent electromagnetic noise in the associated data channel, eg, FIG. The operating state of the wireless communication link 12L is shown.

  Similar to FIG. 3, successive connection events of the wireless communication link are indicated by Ci1, Ci2, Ci3, Ci4, etc. along the time axis t. Those skilled in the art will appreciate that the adjacent connection events shown, such as Ci1 and Ci2, can be separated according to the Bluetooth LE protocol by a fairly long sleep period or inactivity period, eg, up to 4 seconds.

  Within the first connection event Ci1, the high priority data packet A1 is transmitted for the first time, resulting in limited success. The receiving device receives the data packet, but a transmission error is detected, for example in the CRC, and the receiving device sends a negative acknowledgment signal or data packet “Nack”, possibly in the same connection event Ci1. To request retransmission of data packet A1, the MD bit discussed above is set to “1”. Thus, data packet A1 is retransmitted in the same connection event Ci1, but in this example, a transmission error is detected in the receiving device, again with the same result as before. Optionally, to save power, the receiving device does not transmit a second “Nack” signal or packet.

  Thereafter, a first retransmission in the subsequent connection event Ci2 is performed, but a transmission error is subsequently detected in the receiving device, a negative acknowledgment signal or data packet “Nack” is transmitted, and in some cases The MD bit discussed above is set to “1” to request retransmission of the data packet A1 within the same connection event Ci2. Thus, the data packet A1 is retransmitted within the same connection event Ci2, but again results in a transmission error being detected in the receiving device.

  As a result, the data packet A1 is flushed due to time-out, and the transmitting device obtains the next high priority data packet A2 and transmits it in the connection event Ci3. The transmission is successful and the receiving device acknowledges receipt of data packet A2. There is no data packet with a lower priority waiting to be transmitted in the transmitter, so that the MD bit is set to “0” in the header of the second high priority data packet A2, Thus, the receiving device skips the fourth connection event Ci4, thereby saving power.

  In the example shown, the predetermined maximum number of retransmissions within a new connection event for high priority data packets is 1, but a larger maximum value may be selected, for example 2, 3, or 4. . The transmitting device is configured to retransmit the low priority data packet until a reception acknowledgment is received from the receiving device, that is, without limiting the number of retransmissions to the maximum number selected. Also good.

  Limiting the number of retransmissions of a particular high priority data packet to the selected maximum number facilitates maintaining the real time characteristics of the data packet received at the receiving device. If the number of retransmissions of a specific high priority data packet reaches the predetermined maximum number without success, the transmitting device either flushes the specific high priority data packet or Overwrite the packet with, for example, a new high priority data packet representing the current audio content, and then send the new high priority data packet. The loss of the former high priority data packet can be concealed by the receiving device by an appropriate packet loss concealment algorithm executed by the hearing loss processor 24L of the left hearing aid, for example.

  If the transmitted data packet is lost, the receiving device will not send any signal, such as a “Nack” signal, and if there is no signal from the receiving device, the connection event will preferably terminate to save power. Thus, preferably, no retransmissions occur within the same connection event that the data packet was originally transmitted.

  In the timing diagram of FIG. 5, transmission of the high-priority data packet A1 is successful in the connection event Ci1, and the receiving device transmits an acknowledgment signal or packet “Ack” to the transmitting device, thereby ensuring reliable reception. Affirmative response. In the header of the first high priority data packet A1, the MD bit is set to “1”, indicating that a new low priority data packet D1 is waiting for transmission to the receiving device. . The transmitting device then transmits a low priority data packet D1 during the same connection event Ci1. The transmission is successful and the receiving device acknowledges the reception. Since the receiving apparatus has successfully received both the high priority data packet A1 and the low priority data packet D1, the receiving apparatus skips the second connection event Ci2, thereby saving the power of the receiving apparatus.

  In connection event Ci3, transmission of the second high priority data packet A2 to the receiving device is successful and the receiving device acknowledges the reception. In the header of the second high priority data packet A2, the MD bit is set to “1”, indicating that a new low priority data packet D2 is waiting for transmission to the receiving device. . The transmitting device then transmits a low priority data packet D2 during the same connection event Ci3. The transmission of the second low priority data packet D2 is unsuccessful and the receiving device does not acknowledge the reception as indicated by the dotted box “Nack”. If the data packet D2 is lost, the receiving device does not transmit anything to the transmitting device, and the receiving device receives the data packet D2, but if a transmission error is detected, the receiving device transmits a “Nack” signal. May be.

  Since there is no high priority data set or packet waiting to be transmitted to the receiving device, the transmitting device subsequently continues to the second data packet D2 having a low priority during the fourth connection event Ci4. Re-send and succeeded this time.

  In FIG. 6, the transmission of the high priority data packet A1 is successful within the connection event Ci1, and the receiving device acknowledges the reliable reception by sending an acknowledgment signal or packet “Ack” to the transmitting device. To do. In the header of the first high priority data packet A1, the MD bit is set to “1”, indicating that a new low priority data packet D1 is waiting for transmission to the receiving device. The transmitting device then transmits a low priority data packet D1 during the same connection event Ci1. The transmission of the low priority data packet D1 fails and the receiving device does not acknowledge the reception as indicated by the dotted box “Nack”. If the data packet D1 is lost, the receiving device does not transmit anything to the transmitting device, and the receiving device receives the data packet D1, but if a transmission error is detected, the receiving device transmits a “Nack” signal. May be.

  Since there is no high priority data set or packet waiting to be transmitted to the receiving device, the transmitting device continues to re-transmit the second data packet D1 having a low priority during the second connection event Ci2. Although transmission is performed, transmission fails in the connection event Ci2. Within the connection event Ci3, the transmission of the new high priority data packet A2 is not successful and is retransmitted as already explained above. After successful retransmission of the high priority data packet A2, the transmission of the low priority data packet D1 to the receiving device is finally successful within the connection event Ci4.

  FIG. 7 shows that the priority of data packets waiting for retransmission increases as a function of, for example, the number of failed retransmission attempts, and the priority of data packets waiting for retransmission increases to high priority. It shows that a higher priority can be obtained than a data packet having.

  In FIG. 7, the transmission of the high priority data packet A1 is successful in the connection event Ci1, and the receiving device acknowledges the reliable reception by sending an acknowledgment signal or packet “Ack” to the transmitting device. To do. In the header of the first high priority data packet A1, the MD bit is set to “1”, indicating that a new low priority data packet D1 is waiting for transmission to the receiving device. . The transmitting device then transmits a low priority data packet D1 during the same connection event Ci1. The transmission of the low priority data packet D1 fails and the receiving device does not acknowledge the reception as indicated by the dotted box “Nack”. If the data packet D1 is lost, the receiving device does not transmit anything to the transmitting device, and the receiving device receives the data packet D1, but if a transmission error is detected, the receiving device transmits a “Nack” signal. May be.

  After a retransmission failure, the priority of the data packet D1 is set to the highest value, and the transmitting device subsequently continues to the first data having a high priority at this point during the second connection event Ci2. -The packet D1 is retransmitted, but the transmission fails in the connection event Ci2. The transmission of the data packet D1 fails again in the connection event Ci3, but the transmission of D1 to the receiving device finally succeeds in the connection event Ci4. Furthermore, transmission of a new high priority data packet A2 to the receiving device is successful within the same connection event Ci4.

  FIG. 8 shows a flowchart of an example of the novel method.

  The illustrated method 500 can transmit audio, such as voice and / or music, from a transmitting device housed in, for example, a smartphone configured to be suitable for operation compliant with the Bluetooth LE standard protocol, such as a hearing aid or headphones, or another It can be used to stream to a receiving device housed in a hearing device.

  According to the illustrated method 500, when streaming is requested, the audio data to be streamed is packed into audio data packets, also referred to as audio data sets throughout this disclosure, according to the Bluetooth LE standard protocol. Audio data packets are given high priority so that transmission of audio data packets is not hindered by other data such as control data, eg commands to increase the volume of the hearing device .

Audio data packets are transmitted in sequence by the following steps.
510: Establishing one connection event of a series of consecutive connection events in accordance with the Bluetooth LE standard protocol;
520: Giving high priority to at least one audio data packet or audio data set from a series of audio data packets or audio data sets to be streamed from a transmitting device to a receiving device Sending to receive,
530: Waiting for an acknowledgment of reception from the receiving device.
540: If there is no acknowledgment of reception from the receiving device, 520: retransmit at least one audio data packet or audio data set.
550: If there is an acknowledgment of reception from the receiving device,
560: Lower than the priority given to the audio data packet when the transmitting device would have retransmitted at least one audio data packet or audio data set without an acknowledgment Transmitting a second data packet or data set having a second priority from the transmitting device to the receiving device;

  Preferably, in order to ensure high fidelity or at least acceptable quality of the sound generated based on the streamed audio, the audio data packet of the streamed audio has a high priority, thereby , To ensure that audio data packets are transmitted before transmitting other types of data sets with lower priority.

  The method may further include assigning an L2CAP channel to transmission of the audio data set, eg, assigning one L2CAP channel to control data associated with the audio data set, and / or one By assigning an L2CAP channel to the first audio data set and possibly assigning another L2CAP channel to the second audio data set.

The following three fixed L2CAP channels can be allocated for audio transmission.
1) Control data (start, stop, codec negotiation, etc.)
2) Left audio data 3) Right audio data

  For devices that can receive one audio stream (left or right), for example in hearing aids, only channels 1) and 2) or channels 1) and 3) are used for that device. For example, in a device with an integrated stereo function such as a stereo headset, all three channels are used. The audio data set may be unidirectional or bidirectional depending on the field of application, and the control data channel should allow negotiation on that point.

FIG. 9 shows a flowchart of another example 500 ′ of the novel method that includes the following steps in addition to the steps of method 500 shown in FIG.
In step 520: in at least one data packet, whether or not a data set having the second priority is waiting for transmission to the receiving device, eg encoded into a data byte or a data bit. Step to include information.
570: checking whether a data set having the second priority is waiting for transmission to the receiving device;
580: between the transmitting device and the receiving device to transmit the second data set having the second priority when there is no data set having the second priority waiting for transmission to the receiving device. Stopping the establishment of the connection.
590: If a data set having the second priority is waiting for transmission to the receiving device,
560: Lower than the priority given to the audio data packet when the transmitting device would have retransmitted at least one audio data packet or audio data set without an acknowledgment Transmitting a second data packet or data set having a second priority from the transmitting device to the receiving device;

FIG. 10 shows a flowchart of another example 500 ″ of the novel method that includes the following steps in addition to the steps of method 500 shown in FIG.
In step 510: setting the counter of the number of retransmission attempts of the audio data packet transmitted in step 520 to zero.
In step 520: incrementing the counter by one.
540: If there is no acknowledgment of reception from the receiving device,
600: Checking the value of the counter of the number of retransmission attempts of the audio data packet.
610: If the value is less than 2, 520: increment the counter by 1 and retransmit at least one audio data packet or audio data set.
620: if the value is equal to 2, 560: in the audio data packet when the transmitting device would have retransmitted at least one audio data packet or audio data set if there was no acknowledgment Transmitting a second data packet or data set having a second priority lower than a given priority from the transmitting device to the receiving device.

  Additional method steps 600, 610, and 620 may be added to the method 500 ', as shown in FIG. 11, which shows a flow diagram of another example 500 "" of a novel method.

  The allowed number of retransmission attempts for other types of data may be different from 1 and may not be limited, i.e., a maximum value different from 2, no maximum value, or an infinite maximum value may vary. May be assigned to different types of data.

  Different types of data may have different predetermined maximum values for retransmission attempts, for example, an audio data set may have a maximum value of 2, while the audio data set priority The maximum value of a data set having a priority lower than that may have a larger maximum value.

Advantageously, the illustrated novel method facilitates the transmission of audio data packets or sets utilizing Bluetooth LE in a limited way utilizing Bluetooth LE control and link layer extensions. For example, operations related to security and link setup are performed as specified in the Bluetooth core specification.
The technical features described in the specification are listed.
(Feature 1)
A method of wirelessly communicating data sets,
Transmitting a first data set of a first data category for reception from a transmitting device to a receiving device;
Retransmitting the first data set if there is no acknowledgment of receipt from the receiving device;
If there is an acknowledgment of the reception from the receiving device, the first data category when the transmitting device and the receiving device would have been connected for the retransmission without the acknowledgment Transmitting a second data set of a second data category different from the transmitting device to the receiving device.
(Feature 2)
The method of claim 1, wherein the first data set has a first priority and the second data set has a second priority that is lower than the first priority.
(Feature 3)
Signaling whether the data set of the second data set is waiting for transmission to the receiving device from the transmitting device to the receiving device;
The transmitting device and the receiving device for transmitting the data set of the second data set when there is no data set of the second data set waiting to be transmitted to the receiving device; And stopping establishing the connection between the two.
(Feature 4)
The method of feature 2, wherein information regarding whether a data set of the second data set is waiting for transmission to the receiver is encoded into a single data bit.
(Feature 5)
5. A method according to any of features 1 to 4, comprising transmitting and receiving data compliant with the Bluetooth Low Energy standard.
(Feature 6)
5. The method of feature 4, comprising assigning an L2CAP channel for transmission of an audio data set.
(Feature 7)
6. The method of feature 5, comprising assigning one L2CAP channel to control data associated with an audio data set.
(Feature 8)
The method of feature 5 or 6, comprising the step of assigning one L2CAP channel to the first audio data set.
(Feature 9)
The method of feature 7, comprising assigning another L2CAP channel to the second audio data set.
(Feature 10)
If there is no acknowledgment of reception of the audio data set from the receiving device, the audio data set is subject to the condition that the number of retransmission attempts of the same audio data set is less than a predetermined maximum value. The method according to any of features 4 to 8, comprising the step of retransmitting.
(Feature 11)
10. The method of feature 9, wherein the maximum value is 2.
(Feature 12)
11. The method of feature 9 or 10, wherein different types of data have different predetermined maximum values for retransmission attempts.
(Feature 13)
Transmission delay difference between at least two different receiving devices connected to receive different audio data sets to at least one receiving device configured to receive audio data sets from said transmitting device 13. A method according to any of features 1 to 12, comprising transmitting synchronization data including timing information associated with.
(Feature 14)
13. The method of feature 12, comprising determining synchronization data based on a ping transmission from the transmitting device to at least two different receiving devices.
(Feature 15)
14. The method of feature 13, comprising ping transmission utilizing an L2CAP control channel.
(Feature 16)
A hearing device comprising a communication controller configured to be suitable for operation by the method according to any of features 1-15.
(Feature 17)
The hearing device of feature 15, wherein the hearing device is a hearing aid.

Claims (15)

A method of wirelessly communicating a data set in accordance with the Bluetooth Low Energy standard , wherein an audio data set has a higher priority and other types of data having a lower priority. The method, wherein the method is reliably transmitted prior to transmission of the set, comprising:
Transmitting an audio data set having a first priority for reception from a transmitting device to a receiving device;
If there is no acknowledgment of receipt from the receiving device, in the same connection event the connection event where the audio data set is transmitted, and re-transmitting the audio data set,
A control having a second priority lower than the first priority in the same connection event as the connection event in which the audio data set was transmitted if there is the acknowledgment of the reception from the receiver Transmitting the data set. Whether there is a data set of the control data set transmission wait Previous Symbol receiving apparatus, comprising the steps of signal transmission from said transmitting device to said receiving device,
Stopping establishing the connection between the transmitting device and the receiving device for transmission of the control data set if there is no control data set awaiting transmission to the receiving device; including method of claim 1. Information on whether there is a data set of the control data set transmission wait Previous Symbol receiving device is encoded in a single data bit, the method of claim 2. If there is no acknowledgment of reception of the audio data set from the receiving device, the number of re-transmission attempts of the same audio data set is less than a predetermined maximum value. comprising the step of retransmitting the set a method according to any of claims 1 to 3. The method of claim 4, wherein the maximum value is two. The method according to claim 4 or 5, wherein different types of data have different predetermined maximum values for retransmission attempts. The L2CAP channel comprises assigning the transmission of the audio data set, the method according to any one of claims 1 to 6. 5. The method of claim 4 , comprising assigning one L2CAP channel to control data associated with the audio data set. 6. The method according to claim 4 or 5 , comprising the step of assigning one L2CAP channel to the first audio data set. 7. The method of claim 6 , comprising assigning another L2CAP channel to the second audio data set. Wherein the transmitting apparatus, the audio in each of the at least one receiving device configured to receive the data set, at least 2 connected to receive the first and second audio data set 11. The method of claim 10 , comprising transmitting synchronization data that includes timing information related to transmission delay differences between two different receiving devices. 12. The method of claim 11 , comprising determining synchronization data based on a ping transmission from the transmitting device to at least two different receiving devices. 13. The method of claim 12 , comprising ping transmission utilizing an L2CAP control channel. Hearing device comprising a configured communication controller so as to be suitable for operation by the method according to any of claims 1 13. The hearing device is a hearing aid, the hearing device according to claim 1 4.