Method for wireless communication between two devices, hearing instrument system, medium

Abstract

The present invention relates to a method, a hearing instrument system, a medium for wireless communication between two devices. A hearing instrument, such as a hearing aid, can improve the quality of the presented audio by using a binaural application such as beamforming. This binaural application can require communication between the hearing instruments so that audio from the left hearing instrument can be combined with audio from the right hearing instrument. This combination at the hearing instruments can require synchronizing locally sampled audio with sampled audio received from the wireless communication. If the latency of the wireless communication is not low (e.g. a few samples delay), this synchronization can cause a significant delay of the output of the binaural application. A low latency communication protocol is presented herein that transmits packets on a sample by sample basis and compensates for the delay caused by overhead protocol data transmitted with the audio data.

Description

[0001] Cross-references to related applications

[0002] This patent application claims priority to U.S. Patent Application No. 17 / 143,324, filed January 7, 2021. The entire contents of this patent application are incorporated herein by reference. Technical Field

[0003] This disclosure relates to point-to-point wireless communication, and more specifically to digital wireless communication protocols with low latency to facilitate binaural applications for hearing instruments. Background Technology

[0004] Hearing instruments, such as hearing aids or ear-worn speakers (i.e., earplugs), can be worn in / on each of a user's ears to provide sound to the user. Additionally, the hearing instruments may include one or more microphones to receive audio signals from the user's environment. For example, audio from the environment can be received and converted (i.e., sampled) into a first digital signal (i.e., the left channel) by the left-worn hearing instrument, and audio from the environment can be received and converted into a second digital signal (i.e., the right channel) by the right-worn hearing instrument. If the left and right channels can be processed together (i.e., binaural processing), then processing to improve the user's listening experience is possible. Such binaural processing may require digital communication between the hearing instruments and the synchronization of the left and right channels. Summary of the Invention

[0005] In at least one aspect, this disclosure generally describes a method for wireless communication between two devices. The method includes designating a first device as a master device and a second device as a slave device. The master and slave devices transmit data over frames by transmitting protocol packets at regular intervals from the master device to the slave device in a first half of the frame and at regular intervals from the slave device to the master device in a second half of the frame. Each transmitted protocol packet adds a delay to the wireless communication. Therefore, the method also includes transmitting data packets during the regular intervals between the protocol packets. The data packets are transmitted alternately between the master and slave devices. The number of bits in the data packets is less than the number of bits in the protocol packets, such that the delay added by each protocol packet is compensated by the data packets transmitted between the protocol packets.

[0006] In another aspect, this disclosure generally describes a hearing instrument system. The hearing instrument system includes a first hearing instrument designated as a master device and configured to be worn on a user's first ear. The first hearing instrument includes a first microphone, a first speaker, a first transceiver configured for wireless communication, and a first processor configured to execute software instructions stored in a first memory. When executed, the software instructions cause the first processor to transmit, in packets, a first channel of audio samples collected at the first microphone, each packet containing one audio sample, such that a packet is transmitted upon collection of each audio sample. The hearing instrument system also includes a second hearing instrument designated as a slave device and configured to be worn on a user's second ear. The second hearing instrument includes a second microphone, a second speaker, a second transceiver configured for wireless communication, and a second processor configured to execute software instructions stored in a second memory. When executed, the software instructions cause the second processor to transmit, in packets, a second channel of audio samples collected at the second microphone, each packet containing one audio sample, such that a packet is transmitted upon collection of each audio sample. It also enables the second processor to receive a first channel of audio samples collected at the first microphone, combine the first and second channels for binaural applications, and couple the output of the binaural application to the second speaker.

[0007] In another aspect, this disclosure generally describes a non-transitory computer-readable medium including instructions stored thereon that, when executed by a processor of a first hearing instrument, cause the first hearing instrument to perform operations. The operations include transmitting a preamble packet to a second hearing instrument, wherein the transmission of the preamble packet causes a first delay corresponding to the time taken to transmit the preamble data of the preamble packet. The operations also include transmitting a plurality of data packets after the preamble packet at a rate compensating for the first delay. The operations further include transmitting a message packet to the second hearing instrument, wherein the transmission of the message packet causes a second delay corresponding to the time taken to transmit the message data of the message packet. The operations also include transmitting a plurality of data packets after the message packet at a rate compensating for the second delay. The operations further include transmitting a cyclic redundancy check (CRC) packet to the second hearing instrument, wherein the transmission of the CRC packet causes a third delay corresponding to the time taken to transmit the CRC data of the CRC packet. The operations also include transmitting a plurality of data packets after the CRC packet at a rate compensating for the third delay.

[0008] In a possible implementation of a method for wireless communication between two devices, the two devices are a left hearing instrument and a right hearing instrument.

[0009] In another possible implementation of the method for wireless communication between two devices, the protocol data is preamble data, synchronization data, message data, or cyclic redundancy check (CRC) data, and the audio data is a sample of an audio signal. In this implementation, the protocol data can be 16 bits, and the delay can be less than 200 microseconds. Furthermore, the audio data can be encoded.

[0010] In another aspect, this disclosure generally describes a hearing instrument system comprising: a first hearing instrument designated as a master device, configured to be worn on a user's first ear; and a second hearing instrument designated as a slave device, configured to be worn on a user's second ear. The first hearing instrument includes a first microphone, a first speaker, a first transceiver configured for wireless communication, and a first processor. The first processor is configured to execute software instructions stored in a first memory. When the software instructions are executed, the software instructions cause the first processor to transmit, in packets, a first channel of audio samples collected at the first microphone, each packet containing one audio sample, wherein each packet is transmitted upon collection of each audio sample. The second hearing instrument includes a second microphone, a second speaker, a second transceiver configured for wireless communication, and a second processor. The second processor is configured to execute software instructions stored in a second memory. When the software instructions are executed, the second processor is configured to transmit, in packets, a second channel of audio samples collected at a second microphone, each packet containing one audio sample, wherein each packet is transmitted upon collection of each audio sample. In addition, the second processor is configured to receive a first channel of audio samples collected at the first microphone, combine the first channel and the second channel for binaural applications, and couple the output of the binaural applications to the second speaker.

[0011] In a possible implementation of a hearing aid system, the packet is transmitted as each audio sample is collected, such that the delay in wireless communication is on the order of the sampling period of the audio sample. For example, the order of the sampling period could be microseconds.

[0012] In another possible implementation of the hearing instrument system, each packet containing an audio sample comprises a protocol packet and a data packet. For example, protocol packets and data packets are transmitted in a frame, wherein the protocol packet is separated by multiple data packets.

[0013] In another aspect, this disclosure generally describes a non-transitory computer-readable medium including instructions stored thereon. When executed by a processor of a first hearing instrument, the instructions cause the first hearing instrument to perform operations. These operations include transmitting a preamble packet to a second hearing instrument, wherein the transmission of the preamble packet causes a first delay corresponding to the time taken for the preamble data to be transmitted. The operations also include transmitting a plurality of data packets after the preamble packet at a rate compensating for the first delay. The operations further include transmitting a message packet to the second hearing instrument, wherein the transmission of the message packet causes a second delay corresponding to the time taken for the message data to be transmitted. The operations also include transmitting a plurality of data packets after the message packet at a rate compensating for the second delay. The operations also include transmitting a Cyclic Redundancy Check (CRC) packet to the second hearing instrument, wherein the transmission of the CRC packet causes a third delay corresponding to the time taken for the CRC data to be transmitted. The operations also include transmitting a plurality of data packets after the CRC packet at a rate compensating for the third delay.

[0014] In a possible implementation, the preamble packet, message packet, CRC packet, and each data packet include an audio data sample, and the packet is transmitted at a rate that is the average sampling rate of the audio data.

[0015] The foregoing illustrative invention, as well as other exemplary objectives and / or advantages and implementation methods of this disclosure, are further explained in the following detailed description and accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a schematic block diagram illustrating a beamforming process according to an embodiment of the present disclosure.

[0017] Figure 2 A block diagram of a binaural sound system including a hearing instrument communicating via near-field magnetic induction (NFMI) is shown according to a possible embodiment of the present disclosure.

[0018] Figure 3 This is a block diagram of a hearing device according to a possible embodiment of the present disclosure.

[0019] Figure 4 A timing diagram of a low-latency communication protocol according to a possible implementation of the present disclosure is shown.

[0020] Figure 5 Frames of uplink and downlink data streams according to a possible implementation of a low-latency communication protocol according to an embodiment of the present disclosure are shown.

[0021] Figure 6 This is a flowchart of a method for wireless communication according to a possible embodiment of the present disclosure.

[0022] Figure 7 The images show frames transmitted in packets from master and slave devices at various stages of a wireless communication protocol, according to possible embodiments of this disclosure.

[0023] The components in the accompanying drawings are not necessarily drawn to scale relative to each other. Similar reference numerals may be used in several drawings to indicate corresponding parts. Detailed Implementation

[0024] Binaural processing can improve a user's listening experience by processing audio received at different hearing devices (e.g., worn in each of a user's ears). For example, a deaf user can hear combined left and right audio channels in their hearing ear, making it easier to hear sounds on the side of the user's deaf ear. In another example, a user can use a binaural processing technique called beamforming to receive audio with reduced noise. Binaural processing may require wireless digital communication of sound data between the left and right hearing devices and synchronization of the sound data before processing. Conventional radio frequency (RF) digital communication protocols (e.g., Bluetooth, WiFi) may introduce communication delays (i.e., transmission delays, latency) that can negatively impact binaural processing. This document discloses circuits and methods for improving wireless digital communication and synchronization of audio data to facilitate binaural processing such as beamforming.

[0025] Beamforming can be performed on audio from two spatially separated microphones on a single hearing instrument (i.e., monoaural beamforming); however, beamforming performed on audio from microphones on a left hearing instrument located at the user's left ear and a right hearing instrument located at the user's right ear (i.e., binaural beamforming) can offer several advantages. For example, the audio from the left and right hearing instruments can have interaural delay and amplitude differences derived from the spacing between the left / right ears and the direction of sound, which can improve the quality of beamforming.

[0026] Figure 1 This is a schematic block diagram illustrating an example beamforming process. The example beamforming process has been simplified for understanding. Variations of this example beamforming process are possible and are within the scope of this disclosure. For example, the number of microphones, their arrangement (e.g., spatial spacing), and their response (e.g., amplitude) can be adjusted to suit a particular application / environment.

[0027] like Figure 1As shown, the first microphone (M1) and the second microphone (M2) are spatially separated by a distance (d). This spatial separation distance (d) and the sound direction introduce an interaural delay 105 between a first time when the sound arrives at the first microphone (M1) and a second time when the sound arrives at the second microphone (M2). The beamforming process 100 includes a buffer delay 110 applied to one audio stream in the audio stream (e.g., audio from the first microphone (M1)). This buffer delay 110 can be used to synchronize the audio streams and / or create a delay between the audio streams used for beamforming. The beamforming process also includes a combiner 120 configured to combine (e.g., summarize) the audio streams into a beamformed audio stream 130. By adjusting the buffer delay 110 (e.g., relative to the interaural delay 105), the audio from a particular direction can be adjusted (e.g., canceled, attenuated, enhanced) by the beamforming process. For example, if the pure sine wave received by M1 and M2 can be completely canceled in a specific direction after an interaural delay of 105 and a buffer delay of 110, then the version of the sine wave at combiner 120 is 180 degrees out of phase.

[0028] The quality of the audio adjustments (i.e., cancellation, attenuation, enhancement) produced by beamforming can depend on the matching performance of the first microphone (M1) and the second microphone (M2). Additionally, the spatial distribution (i.e., directivity) of the beamforming can be affected by the spatial spacing (d) between the first microphone (M1) and the second microphone (M2). A small spatial spacing (d) can produce an interaural delay of 105, which changes little (if at all) in the direction of the sound. As the spatial spacing (d) of the microphones increases, spatial filtering that may originate from the beamforming can be increased. Therefore, it might be desirable to position the first microphone (M1) at the user's left ear and the second microphone (M2) at the user's right ear (or vice versa). This positioning can also add realism to the beamforming by preserving the amplitude and phase of the audio stream as it would typically occur at each of the user's ears.

[0029] A relatively large spatial spacing (d) may require transmitting sound data from one microphone to another. (Reference) Figure 1 If beamforming processing 100 is located locally at the first microphone (M1) (e.g., included in the left hearing instrument), then sound data from the second microphone (M2) (e.g., from the right hearing instrument) can be transmitted to beamforming processing 100. Wireless communication of sound data may be required in many applications (e.g., in hearing instruments), but a communication delay 140 (i.e., a timeout) can be introduced. Figure 1 The beamforming shown.

[0030] As mentioned, conventional wireless communication protocols can result in relatively large communication delays 140. However, increasing the buffer delay 110 to compensate for the communication delay 140 may reduce the quality of beamforming (i.e., may reduce the user's listening experience). For example, due to the buffer delay necessary to compensate for the communication delay 140, the communication delay can result in an audio stream 130 that is visually out of sync with the sound source (especially for high-frequency sounds).

[0031] The disclosed circuits and methods describe a wireless communication system that includes a communication protocol that minimizes communication latency (i.e., provides ultra-low latency) to allow for improved performance in binaural applications, such as beamforming. Additionally, the communication protocol can utilize wireless communication technologies well-suited for stereoscopic hearing instruments.

[0032] Conventional digital wireless communication may involve the propagation of radio frequency (RF) signals (e.g., 2.4 GHz) between a transmitter antenna and a receiver antenna. For conventional digital wireless communication, such as Bluetooth and WiFi, the RF signal is designed to propagate according to the far-field transmission principle. Using these forms of digital wireless communication between hearing instruments worn in opposite ears can result in (at least) inefficiency and interference with other devices. To avoid these problems, the disclosed circuits and methods may utilize near-field magnetic induction (NFMI) communication technology, which is more suitable for wireless communication between wearable devices such as hearing instruments.

[0033] Figure 2 A block diagram of a binaural sound system including hearing instruments communicating via NFMI, according to a possible embodiment of the present disclosure, is shown. The binaural sound system 200 includes two hearing instruments. Each hearing instrument 300 may be configured to be worn near or in contact with a user's ear. For example, in a possible embodiment, the hearing instruments are a left hearing instrument and a right hearing instrument worn (at least partially) in the user's ear canal. Each hearing instrument 300 may include one or more speakers for projecting emitted sound 210 (e.g., a beamforming audio stream) from the hearing instrument. Each hearing instrument 300 may also include one or more microphones for receiving received sound 220 from the environment. Each hearing instrument 300 may also include a transmitter and / or receiver. For example, each hearing instrument 300 may include a transmitter / receiver (T / R) configured to transmit and receive digital data via a wireless communication link 230 (e.g., a bidirectional wireless communication link). As previously mentioned, the wireless communication link 230 may include an NFMI.

[0034] NFMI facilitates digital communication over short ranges (e.g., <1 meter (m)). For NFMI communication, each hearing instrument 300 may include a coil 240 of a transmitter / receiver coupled to the hearing instrument 300. The transmitter of the first hearing instrument may be configured to excite a current in the transmitter coil 240 to generate a magnetic field 250 inductively coupled to the coil 240 of the receiver of the second hearing instrument. This magnetic field 250 may be modulated (e.g., frequency shift keying (FSK)) for transmitting digital information between the hearing instruments. The coils may be substantially similar (e.g., identical) and may be arranged to increase magnetic coupling so that the efficiency of NFMI can be high. Furthermore, the magnetic field 250 may be tightly coupled and have an amplitude that decreases rapidly with range because it does not propagate (i.e., near-field emission). Therefore, NFMI communication can minimize interference with other devices. For digital communication, the magnetic field 250 may be modulated in the high-frequency (HF) band (e.g., 10-14 MHz). HF band signals can experience less distortion / absorption from the human body than higher frequency signals (e.g., 2.4 GHz).

[0035] Figure 3 It shows that it can be used Figure 2 A block diagram of a hearing instrument 300 for a binaural audio system. As previously mentioned, the hearing instrument may include a transmitter / receiver coupled to a wireless transducer (such as an antenna or coil). This transmitter / receiver may be implemented as a discrete transmitter and receiver, or as a transmitter / receiver device including a transmitter portion and a receiver portion. For Figure 3 In the illustrated hearing instrument implementation, the transmitter / receiver 310 (i.e., transceiver) can transmit and receive digital data (e.g., audio data streams) via a wireless communication link 230 through a coil 240 configured for NFMI.

[0036] The hearing instrument 300 includes at least one microphone (i.e., mic) 320, which is configured to convert received sound 220 into an analog microphone signal 321. The analog microphone signal 321 is coupled to an analog-to-digital converter (i.e., A / D 330), which is configured to periodically sample the analog microphone signal 321 at a sampling rate (e.g., 24 kHz) to generate digital samples with an amplitude resolution (e.g., 16 bits) corresponding to a binary representation, and to sequentially output the digital samples as a digital data stream 331. Digital data stream 331 can be transmitted to a processor (e.g., a digital signal processor, i.e., DSP 340), which can be configured to use digital data stream 331 as a channel in binaural applications such as beamforming. In a possible implementation, the hearing instrument may include a delay unit 335 (e.g., a buffer delay unit 110) configured to generate a buffered digital data stream 332 that is buffered for a period of time before being provided to the DSP 340. The delay unit 335 can be used to synchronize the DSP. The data stream at 340 (e.g., local and received) can also be used for binaural applications (e.g., beamforming). The digital data stream 331 can also be provided to an encoder 344 configured to encode (e.g., compress) the digital data stream to reduce the number of bits (i.e., bandwidth) transmitted over the wireless communication link 230. The encoder 344 can be part of an audio codec 350 that includes (at least) an encoder 344 and a decoder 345. The audio codec 350 can be one of several possible types, including (but not limited to) an adaptive differential pulse code modulation (ADPCM) codec. The encoder 344 can output the encoded data stream 341 for transmission to the transmitter portion of a transmitter / receiver 310 for transmission to another hearing instrument (not shown).

[0037] The transmitter / receiver 310 may also include a receiver section configured to receive an encoded data stream from another hearing instrument (not shown) via a wireless communication link 230 through a coil 240. The receiver section may couple the received encoded data stream 342 to a decoder 345. The decoder 345 may be configured to decode (e.g., decompress) the received encoded data stream and output the received digital data stream 346 to a DSP 340.

[0038] DSP 340 can be configured to receive / process buffered digital data stream 332 (i.e., the first channel, the local channel) and received digital data stream 346 (i.e., the second channel, the remote channel, the received channel) for binaural applications, and is configured to output processed digital data stream 351. Processed digital data stream 351 can be a combination of buffered digital data stream 332 and received digital data stream 346. In a possible implementation, DSP 340 is configured (e.g., via software) to perform beamforming processing on the first and second channels in pairs. In this case, processed digital data stream 351 is beamformed audio stream 130.

[0039] The hearing instrument 300 may also include a non-transitory computer-readable medium (i.e., memory 360). The memory 360 may be configured to store a computer program product (i.e., software) including instructions that, when executed by a processor, can configure the processor to perform operations to implement the functions of the hearing instrument. For example, the memory 360 may include stored instructions that can configure a DSP 340 to perform beamforming processes (i.e., methods). Additionally or alternatively, the memory may include stored instructions that can configure a processor (e.g., DSP 340) to perform methods associated with an ultra-low latency NFMI communication protocol.

[0040] The hearing instrument 300 may also include a digital-to-analog converter (i.e., D / A 355) configured to parse digital samples of the processed digital data stream 351 and generate an analog speaker signal 324 based on the digital samples. The analog speaker signal 324 may be amplified (not shown) and coupled to at least one speaker 325 of the hearing instrument 300 to produce emitted sound 210. Due to binaural application, the emitted sound 210 can provide the user with an improved listening / hearing experience. For example, the emitted sound may include less noise than emitted sound without the processing provided by the binaural application.

[0041] As mentioned, Figure 3 The hearing device 300 shown can be one of two hearing devices worn in a user's ears. In this case, the hearing device worn in the left ear can be the same as the hearing aid worn in the right ear. In other words, processing can be performed at each hearing device. Alternatively, the first hearing device in a pair may include a subgroup of circuitry / subsystems as the second hearing device in the pair. In other words, processing for binaural applications can be performed at one of the hearing devices in the pair. In either case, a wireless communication link 230 between the hearing devices may be required. The wireless communication link 230 may include a low-latency communication protocol to prevent problems in processing for binaural applications.

[0042] Figure 4 A timing diagram of a low-latency communication protocol according to a possible implementation of this disclosure is shown. In the forward direction (i.e., right HI to left HI), microphone A / D samples are processed immediately on a sample-by-sample basis by a codec and a channel encoder. The encoded data is then formatted into small packets, each representing a sample, and wirelessly transmitted at a high data rate. Next, the left HI receives the transmitted signal and decodes the demodulated packets. The demodulated data is decoded sample-by-sample to generate D / A samples. The D / A samples are converted into analog audio for the left speaker. The communication latency in the example is 3 sampling periods, which is 125 microseconds for a 24kHz sampling rate. In other words, the communication latency is only a few sampling periods and is primarily due to encoding / decoding.

[0043] Figure 4 This includes multiple graphs of the signal plotted relative to the same time axis. These graphs can be grouped using different hearing instruments. The graphs include one for a first hearing instrument (e.g., right hearing instrument 401). The graphs also include one for a second hearing instrument (e.g., left hearing instrument 402). The graphs illustrate the timing associated with bidirectional audio communication between the left hearing instrument (left HI) and the right hearing instrument (right HI) to provide a visual understanding of communication delays (i.e., latency). The timing can be expressed based on the sampling time (i.e., sampling period) used for the audio signal (e.g., 41.67 microseconds (μs) / sample), which is typically the same for each hearing instrument.

[0044] At the right hearing aid, microphone audio is sampled to form a right audio data stream comprising multiple audio samples. In conventional communication protocols (e.g., Bluetooth, WiFi), multiple samples are collected to form blocks that can be encoded and transmitted in packets. When each packet (e.g., as in Bluetooth, WiFi) requires a certain amount of overhead data, the efficiency of packet communication can be increased by increasing the block size. Additionally, the encoder can work better with large blocks of data. In other words, the amount of compression of data blocks can increase as the size (i.e., length) of the data blocks increases.

[0045] While larger blocks may be necessary for regular communication, they can lead to greater communication latency (i.e., transmission delay, latency). For example, transmitting a data block from a first device to a second device generates communication latency that includes transmission and reception delays. Transmission latency may include a first delay associated with collecting data samples of the data block at the first device, a second delay associated with encoding the data block, and a third delay associated with wirelessly transmitting and encoding the data block. Receiving a data block can generate reception latency, which includes a fourth delay associated with receiving and encoding the data block, a fifth delay associated with decoding the data block, and a sixth delay associated with presenting audio from the data block at the second device.

[0046] When data blocks are large, the communication latency introduced by conventional protocols can be too significant for binaural applications. Binaural applications using a first locally collected audio data stream and a second audio data stream received from a remote device may require synchronization of the audio data streams. Buffering the locally collected audio data stream during communication latency to synchronize it with the remotely collected audio data can result in a delayed output of the processed digital data stream (i.e., the emitted sound). This latency can be exacerbated if packets are corrupted or lost. In hearing instruments (e.g., hearing aids), large latency (e.g., ≥10 milliseconds (msec)) may be unacceptable because the sound may become noticeably out of sync with its visually observable source (i.e., its counterpart). Therefore, the disclosed communication protocol can minimize the block size (e.g., ≤2 samples). For example, as... Figure 4 As shown, the block size is a sample. To prevent the efficiency loss associated with small blocks, the disclosed communication protocol eliminates the top data emitted with each block. Instead, the disclosed communication protocol distributes overhead data (e.g., messages, error correction, synchronization, etc.) across sample frames to manage communication and eliminate errors.

[0047] like Figure 4As shown, microphone audio 405 collected from the microphone at the right HI can be sampled to produce a sequence of A / D samples. Each A / D sample can be represented by multiple bits (e.g., 16 bits). The bits of each sample can be encoded by encoder 409 to produce coded blocks for grouping. The packets can be transmitted to the left HI 402 using a wireless technology (e.g., NFMI). At the left HI, the packets are decoded by decoder 413 and converted into D / A samples 415 so that the audio 417 received from the right HI 401 can be reconstructed at the left HI 402. Because the data blocks in the packets are limited to samples, the delay 420 between the time when the audio is sampled at the right HI 401 and the time when the samples become available at the left HI 402 is small (e.g., about 3 samples). Therefore, a short delay (e.g., about 125 μs) is required to synchronize the audio captured at the left HI 402 (i.e., the left microphone audio 419) with the audio received from the right HI (i.e., the left speaker audio 417). As mentioned above, the left HI 402 can also collect audio and transmit it to the right HI.

[0048] Left HI 402 and Right HI 401 can transmit packets at the same rate but at different times, such that packet 411 (i.e., downlink packet) transmitted by Right HI 401 does not overlap with packet 412 (i.e., uplink packet) transmitted by Left HI 402. To achieve non-overlapping packets, Right HI and Left HI can synchronize using transmission messages that include predetermined data (e.g., synchronization words). For example, before data transmission, the master device (e.g., Right HI) can repeatedly transmit short (e.g., 16-bit) synchronization words to the slave device (e.g., Left HI). Because the synchronization word is known to the slave device, the synchronization can be adjusted until the synchronization word is recognized at the slave device.

[0049] Left HI 402 may not always correctly receive packets from right HI 401 (and vice versa). To correct communication errors, each packet may include a parity bit, which helps the receiving device determine whether the data in the packet is correct or incorrect. Parity bit analysis can determine whether correction is possible. If correction is possible, then the data bits in the packet can be changed to correct the error. If correction is not possible, then the code can apply algorithms (e.g., packet loss concealment) to mitigate the information lost in the error.

[0050] For at least synchronization and error correction, some overhead information can be transmitted in addition to audio data. An advantage of the disclosed low-latency communication protocol is that this overhead information can be transmitted without significantly affecting packet-to-packet latency. For example, messages about communication can be transmitted on a frame-by-frame basis, where a frame comprises multiple (e.g., 128) packets. The latency caused by the messages (i.e., delay) can be balanced by increasing the packet transmission rate so that the latency caused by the overhead information is insignificant (e.g., zero). The scheme and its characteristics can be best understood by considering example frames.

[0051] Figure 5 A frame 500, comprising an uplink data stream 501 (e.g., transmitted by a device designated by the device from a slave device) and a downlink data stream 502 (e.g., transmitted by a device designated by the device from a master device), is shown according to a possible implementation of a low-latency communication protocol. The low-latency communication protocol (i.e., the protocol) includes multiple frames transmitted sequentially. Each frame may be identical and arranged as shown in frame 500. Therefore, frame 500 may include frames with the same arrangement that are exactly before and immediately after the frame shown. A frame includes multiple packets. In each frame, uplink data stream 501 and downlink data stream 502 may transmit packets alternately. The number of packets transmitted in uplink data stream 501 during frame 500 may be equal to the number of packets transmitted in downlink data stream 502 during frame 500. Each packet in the data stream may include an audio data block 512 (i.e., data). As mentioned, the audio data in each packet may correspond to a bit of a sample of an analog audio signal. Each packet may also include a parity bit 516 (i.e., parity check) added by encoder 344 to help diagnose and correct bit errors in the audio data generated by wireless communication. Therefore, data packets (D) can be arranged such that the parity bit is transmitted after the audio bits. In other words, data packet 511 (i.e., D) may include (in sequence) payload (e.g., audio data (i.e., data)) and parity data (i.e., parity). In frame 500, the downlink transmitter and uplink transmitter alternately transmit data packets. For uplink and downlink transmissions to use the same frequency band, time synchronization between the data streams may be required. This initial time synchronization may occur at the start of communication, during the synchronization period (i.e., startup mode). Figure 5 The frame shows the relative timing of packet transmissions after synchronization (i.e., after the start mode of communication).

[0052] Data packets 511 may be samples of audio data (e.g., 16 bits) compressed to a short data length (e.g., 8 bits) by a codec (e.g., ADPCM). Parity checks may be shorter than the compressed audio samples (e.g., 4 bits). Parity checks can be used to detect, and in some cases, correct, errors. The disclosed low-latency communication protocol utilizes parity checks along with each audio data segment in the packets so that retransmitting packets with errors requires no time. Each packet is short, so even if errors cannot be corrected or packets are lost, the impact on the overall data stream may not be significant.

[0053] Some packets in uplink data stream 501 and downlink data stream 502 may also include overhead data (i.e., protocol data) added to data packets (D) (i.e., added to audio data and parity data). For example, synchronization packet 513 (i.e., S+D) may include (in sequence) synchronization data 514 (i.e., SYNC), audio data (i.e., data), and parity data (i.e., parity). Message packet 515 (i.e., M+D) may include (in sequence) message data (i.e., message), audio data (i.e., data), and parity data (i.e., parity).

[0054] Synchronization data 514 can be short (e.g., 16 bits) to prevent synchronization data (S) added to the data packet (D) from significantly delaying the data stream. Synchronization data 514 can include a synchronization word that the receiver can use for synchronization. In other words, during a synchronization period, the receiver may expect to receive a synchronization word. The transmitter may repeatedly transmit the synchronization word, and the receiver may tune itself until it correctly receives the repeated synchronization word, at which point the transmitter and receiver are synchronized. The synchronization word can be relatively short, which can increase the risk of random data being identified as the synchronization word. To mitigate this risk, the receiver can be configured to detect the correct reception of synchronization words for multiple frames.

[0055] Message data 517 may be short (e.g., 16 bits) to prevent message data (M) added to the data packet (D) from significantly delaying the data stream. Message data 517 may include information about the communication, such as the number of packets, packet number, message length, and acknowledgment of the last received message.

[0056] In some cases, the message data is Cyclic Redundancy Check (CRC) data. In this case, the message packet (M+D) may include (in sequence) CRC data 519 (CRC), audio data (i.e., data), and parity check data (i.e., parity check). The CRC data 519 may be short (e.g., 16 bits) to prevent the CRC data added to the data packet (D) from significantly delaying the data stream. The CRC data 519 may include information that helps detect errors in previously sent message data (M). When a message packet includes CRC data, that CRC data may be referred to as a CRC packet.

[0057] Message packets (M+D) and synchronization packets (S+D) can be collectively referred to as protocol packets. Protocol packets can be the same size or different sizes, and can typically have more bits of overhead data (i.e., protocol data) than data packets. Protocol packets can be transmitted at intervals (i.e., regular intervals) within a frame (i.e., they can be distributed throughout the frame). In other words, protocol packets can be spaced apart by multiple data packets (D), such as... Figure 5 As shown.

[0058] When data packets are not delayed in any other way than through protocol packets, they can be transmitted at the data packet rate. In other words, most data packets in a frame can be separated by data packet period 523. When protocol packets 525 are transmitted, data packets surrounding the protocol packets can be separated by delayed packet periods 522. In other words, each delayed packet period in a frame can contribute to the communication delay of the frame. The disclosed low-latency communication protocol can reduce (e.g., eliminate) the communication delay by adjusting the data packet period 523 to compensate for the delayed packet period 522.

[0059] As mentioned, each data packet may include an audio data sample. In this case, communication latency 140 can be minimized when the audio data samples are transmitted on average at the audio data sampling rate. The disclosed low-latency communication protocol maintains the average transmission rate by transmitting data packets at a data packet period 523 that is faster than the audio sampling period 421 (i.e., the sampling period), such that after a delayed packet period 522, the average packet period is the sampling period 421. In other words, the data packet rate (i.e., the data packet period) can compensate for the latency caused by protocol packets (i.e., the delayed packet period). Keeping the average communication latency to a minimum may require appropriate spacing of protocol packets within a frame.

[0060] The transmitters of uplink data stream 501 and downlink data stream 502 can each transmit protocol packets. For example, downlink data stream 502 may include preamble packets, message packets, and message packets containing a CRC in each frame 500. Similarly, uplink data stream 501 may include preamble packets, message packets, and message packets containing a CRC in each frame 500. Frame 500 may be divided into a first portion 520 (e.g., a first half) and a second portion 521 (e.g., a second half) at a 50% offset from the beginning of the frame. In a possible implementation, half (50%) of the data packets for the frame are transmitted in the first portion and half (50%) of the data packets for the frame are transmitted in the second portion. The transmitter of downlink data stream 502 may transmit all its protocol packets in the first portion 520 of frame 500, while the transmitter of uplink data stream 501 may transmit all its protocol packets in the second portion 521 of frame 500.

[0061] Protocol packets are distributed within the frame (e.g., equally). For example, such as Figure 5 As shown, the downlink and uplink data streams may together comprise six protocol packets (i.e., three in uplink data stream 501 and three in downlink data stream 502). In one possible implementation, downlink data stream 502 (e.g., transmitted by the primary HI) may include a synchronization packet (S+D) at the beginning of the frame (i.e., offset 0% from the beginning), a first message packet (M+D) offset 16.7% from the beginning, and a second message packet (M+D) offset 33.3% from the beginning (i.e., a CRC packet). Uplink data stream 501 (e.g., transmitted by the secondary HI) may include a synchronization packet (S+D) offset 50% from the beginning, a first message packet (M+D) offset 66.7% from the beginning, and a second message packet (M+D) offset 83.3% from the beginning (i.e., a CRC packet). In other words, after the message packet (M+D) offset 33.3% from the start, the downlink data stream 502 consists only of data packets, while before the synchronization packet (S+D) offset 50% from the start, the uplink data stream consists only of data packets. At the 100% offset from the start, the synchronization packet (i.e., the preamble packet, header packet) can be transmitted in the downlink data stream 502 for the next frame. In other words, the preamble packet can be transmitted once every N samples by the master transmitter, where N is the number of data packets in the frame. It should be noted that the synchronization packets and message packets (i.e., protocol packets) transmitted in the downlink data stream 502 (e.g., via the master device) may not be the same as the synchronization packets and message packets transmitted in the uplink data stream 501 (e.g., via the slave device).

[0062] Protocol packets are spread across frames to minimize communication latency. For example, a synchronization packet 510 at 0% offset introduces a latency (i.e., delay) related to the sampling rate. Subsequent message packets 515 may not be transmitted until the latency can be compensated by data packets transmitted after the synchronization packet. For example, data packets may be transmitted at a packet transmission rate higher than the sampling rate. In other words, latency compensation can be divided among multiple data packets 524 between the synchronization packet 510 and the message packet 515. Therefore, the data packet transmission rate may need to be only a fraction higher than the sampling rate of the audio signal.

[0063] Figure 6 This is a flowchart of a method for low-latency wireless communication between two devices (e.g., hearing instruments). According to a possible implementation, method 600 includes designating a first device (e.g., a left hearing instrument) 610 as a master device (i.e., primary) and a second device (e.g., a right hearing instrument) as a slave device (i.e., secondary). In other words, a frame may include a number (N) of data packets (e.g., audio samples) transmitted by the master and / or slave devices. Devices may be factory-configured as master or slave devices. For example, hearing instruments sold in pairs (e.g., for sale) may include a configuration such that one hearing instrument always initiates communication as the master device.

[0064] The method also includes transmitting 620 protocol packets (e.g., preamble packets, synchronization packets, message packets, CRC packets) from the master device to the slave device. For example, the left hearing aid can be designated as the master device and a frame can be initiated by transmitting a synchronization packet to the right hearing aid. The synchronization packet may include synchronization data and a payload (e.g., audio samples). The data stream can be delayed based on the time spent transmitting the synchronization data. The delay may be related to the desired transmission rate of the data packets, which in turn may be related to the sampling rate of the audio data at the hearing aid.

[0065] The method also includes transmitting over 630 data packets alternately between the master and slave devices. In other words, the master and slave devices can alternately transmit data packets for a predetermined number of data packets. The data packets can be smaller than the protocol packets (e.g., having fewer bits). The transmission rate of the data packets can be slightly higher than the desired transmission rate so that the delay caused by the preamble packets can be compensated by the data packets. In other words, the delay added by the protocol packets can be compensated by the data packets transmitted after the protocol packets. In other words, the transmission rate of the data packets can deviate from the desired transmission rate during a frame, being slower for protocol packets and faster for data packets, but averaging approximately the desired transmission rate for data packets per frame (i.e., within 1%). Therefore, the number of data packets can be based on the size of the preamble data.

[0066] Protocol packets can be transmitted at intervals (i.e., regular intervals) targeting the first portion (e.g., the first half) of a frame. Therefore, the process of transmitting protocol packets after transmitting data packets can be repeated until all protocol packets for the master device have been transmitted (i.e., until the first portion of the frame is completed 640).

[0067] Shorter data packets transmitted between the master and slave devices can each partially compensate for the delay caused by longer protocol packets. Distributing protocol packets between transmission periods helps minimize communication latency because the average transmission rate of payload data always remains close to the desired transmission rate (e.g., close to the sampling rate). The number of data packets transmitted between each protocol packet in a frame can be the same or can vary. If each protocol packet (i.e., preamble packet, message packet) is the same size, then the number of data packets transmitted at the intervals between protocol packets can be the same.

[0068] When the transmission of the first portion of the frame is complete, method 600 then includes transmitting protocol packets from the slave device to the master device at regular intervals in the second portion of the frame (e.g., the second half). During the second portion, the method also includes transmitting 660 data packets between the master and slave devices in an alternating manner at (regular) intervals between protocol packets. This process may continue until the second portion of the frame is completed 620.

[0069] When the second part of the frame is completed at 620, the method includes starting a new frame at 690 and repeating the above process for the next frame. The frame length can be made longer or shorter depending on the needs of different applications. For example, because the protocol operates on a per-sample basis, the frame length is not determined by the minimum payload size.

[0070] Figure 6 The method shown assumes the devices are synchronized. To synchronize the two devices, the first device can repeatedly transmit a synchronization word to the second device. The second device expects the synchronization word and can adjust its receiver until it correctly receives the synchronization word. After adjustment, the second device can transmit, for example, to the first device... Figure 6 The communication shown can be initiated with confirmation. Details of the possible synchronization phases (i.e., initiation modes) for initiating communication are described below.

[0071] Figure 7 Frames of uplink and downlink data streams for various stages of a low-latency wireless communication protocol according to possible embodiments of the present disclosure are shown. As mentioned, communication between two devices can be synchronized before communication. Therefore, the communication protocol may include a startup mode for synchronization and an operating mode for communication. The startup mode may include a first stage and a second stage, while the operating mode may include a bidirectional mode or a unidirectional mode.

[0072] Details of these patterns can be found in [reference]. Figure 7 Describe it. Figure 7 The following are shown: downlink data streams of packets transmitted by a first hearing instrument designated as a master device (i.e., master device 701) and uplink data streams of packets transmitted by a second hearing instrument designated as a slave device (i.e., slave device 702), and frames 700 for the first phase (i.e., first phase 711) of the startup mode, the second phase (i.e., second phase 712) of the startup mode, and the running mode 713.

[0073] In the first phase 711 of the startup mode, the master device 701 is configured to transmit packets when the slave device 702 is configured not to transmit (i.e., to listen). The transmitted packets include protocol packets (i.e., S+D, M+D) containing a payload of protocol information (e.g., synchronization words, messages, CRC data, etc.) and audio data (e.g., one or more audio samples). The transmitted packets also include (shorter) data packets (i.e., D) containing only audio data. In the first portion (e.g., the first half) of frame 700, the protocol packets are spaced apart from the data packets by intervals (e.g., regular intervals). Communication is similar to... Figure 5 The communication shown, however, uses time slots provided to slave device 702 that are filled instead of repeating pattern data 720 (i.e., repeating pattern data). For example, repeating pattern data packets (i.e., R) may include a binary pattern. The binary pattern may contain 50% zeros and 50% ones. The ones and zeros may be in any order, such as a repeating one-zero-one binary pattern (i.e., ...1010...). Slave device can acquire phase and frequency lock (i.e., synchronization) on the transmitted data. Frames of the first phase 711 may be repeatedly transmitted to allow slave device synchronization. In the second part (e.g., the second half) of frame 700, master device 701 stops transmitting one or more listen cycles. For example, the second part of frame 700 may include a first listen cycle 731, a second listen cycle 732, and a third listen cycle 733. The listen cycle provides time for slave device to respond with its own protocol packets. Slave device can respond after it has synchronized.

[0074] In the second phase 712 of the startup mode, the slave device synchronizes and transmits protocol packets during the listening period. For example, the slave device may transmit a slave device synchronization packet (S+D) during the first listening period 731, a first message packet (M+D) during the second listening period 732, and a second message packet (e.g., a CRC packet (C+D)) during the third listening period 733. These protocol packets sent by the slave device notify the master device that the slave device is synchronized. Therefore, the master device synchronizes with the slave device by using the slave device's synchronization packet (S+D). After the master device synchronizes (e.g., correctly receives the synchronization word), the master device can transmit its synchronization status to the slave device via message packets.

[0075] After the master and slave devices are synchronized, communication can enter operating mode 713. Operating mode 713 can be bidirectional or unidirectional. For example, in Figure 7 The diagram illustrates a bidirectional operating mode. In this mode, the master device 701 and the slave device 702 operate as follows: Figure 5 The transmission protocol packets (S+D, M+D, C+D) and data packets (D) are described. In a unidirectional operation mode (not shown), the master device may transmit only while the slave device is receiving data. Alternatively, the slave device 702 may transmit only while the master device 701 is receiving data.

[0076] The latency of the wireless communication protocol is low because the payload of the data packets (D) can be very small. Each packet can include an audio sample, allowing each sample to be transmitted individually on a sample-by-sample basis to reduce latency in sample communication. For example, packets can be formed on a sample-by-sample basis at a hearing aid. The latency (i.e., communication delay) of the wireless communication protocol is also low (e.g., ≤3 sample periods, <125 μs) because the delay caused by transmitting protocol data (e.g., preamble data, synchronization data, messages, CRC data, etc.) can be compensated for by increasing the packet transmission rate of the data packets, resulting in low latency (e.g., zero) caused by the protocol data. The latency of the wireless communication protocol is also low because there is no retransmission of packets. A parity bit is included with each data packet, so if a data packet is corrupted, it can be repaired. If a data packet is lost, its loss is not significant to the overall data stream. The latency of the wireless communication protocol is also low because the protocol data can remain small (e.g., 16 bits), as binaural applications can reduce the range of information required to implement communication. For at least these reasons, the latency can be described as low compared to other wireless protocols (e.g., Bluetooth, WiFi, UWB, etc.). For example, the latency of the protocol described here can be approximately microseconds (e.g., 125μs (3 samples) for a 24kHz sampling rate) rather than milliseconds.

[0077] Typical embodiments have been disclosed in the specification and / or accompanying drawings. This disclosure is not limited to such exemplary embodiments. For example, although NFMI has been described, the low-latency protocols described herein can be used with other wireless technologies, such as wireless technologies that require the propagation of RF signals.

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Methods and materials similar to or equivalent to those described herein may be used in practice or testing of this disclosure. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include multiple referents unless the context clearly specifies otherwise. The term “comprising” and its variations are used synonymously with the term “comprising” and its variations as used herein and are open-ended, non-limiting terms. The terms “optional” or “optionally” as used herein mean that a feature, event, or condition subsequently described may or may not occur, and the description includes instances where the feature, event, or condition occurs and instances where it does not occur. Scopes may be expressed herein as from “about” a particular value and / or to “about” another particular value. When such a scope is expressed, an aspect includes from one particular value and / or to another particular value. Similarly, when a value is expressed as an approximate value using the antecedent “about,” it should be understood that the particular value forms another aspect. It should also be understood that each endpoint of a range is significant relative to another endpoint and independent of the other endpoint.

[0079] While certain features of the described embodiments have been illustrated herein, many modifications, alternatives, variations, and equivalents will now occur to those skilled in the art. Therefore, it should be understood that the appended claims are intended to cover all such modifications and variations falling within the scope of the embodiments. It should be understood that these modifications and variations are presented by way of example only and not limitation, and various changes in form and detail are possible. Any parts of the apparatus and / or methods described herein can be combined in any way, except for mutually exclusive combinations. The embodiments described herein may include various combinations and / or sub-combinations of the functions, components, and / or features of the different described embodiments.

[0080] It will be understood that in the foregoing description, when an element is referred to as being on, connected to, electrically connected to, coupled to, or electrically coupled to another element, the element may be directly on, connected to, or coupled to the other element, or one or more intermediate elements may be present. Conversely, when an element is referred to as being directly on, directly connected to, or directly coupled to another element, no intermediate elements are present. Although the terms "directly on," "directly connected to," or "directly coupled to" may not be used throughout the specific embodiments, elements shown as being directly on, directly connected to, or directly coupled to an element can be referred to in this manner. The claims of this application (if any) may be amended to describe the exemplary relationships described in the specification or shown in the drawings.

[0081] As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. In addition to the orientations shown in the figures, spatial relative terms (e.g., above, on, above, below, under, beneath, etc.) are intended to cover different orientations of the device in use or operation. In some embodiments, the relative terms above and below may respectively include vertically above and vertically below. In some embodiments, term proximity may include lateral proximity or horizontal proximity.

Claims

1. A method for wireless communication between two devices, the method comprising: The first device is designated as the master device and the second device is designated as the slave device, wherein the master device and the slave device transmit data through frames by means of the following operations: Protocol packets are transmitted from the master device to the slave device at regular intervals in the first half of the frame and from the slave device to the master device at regular intervals in the second half of the frame, with each protocol packet adding a delay to the wireless communication; as well as During the regular intervals between the protocol packets, data packets are transmitted alternately between the master device and the slave device. The number of bits in the data packets is less than the number of bits in the protocol packets. The average transmission rate is maintained by transmitting data packets at a data packet period faster than the sampling period of the audio samples, such that the average packet period is approximately equal to the sampling period, and the delay added by each protocol packet is compensated by the data packets transmitted between the protocol packets.

2. The method for wireless communication between two devices according to claim 1, wherein: Each protocol packet includes protocol data, audio data, and parity data; Each data packet includes audio data and parity data; and The delay added by each protocol packet corresponds to the time required to transmit the protocol data.

3. The method for wireless communication between two devices according to claim 2, wherein the number of data packets transmitted during the regular interval between the protocol packets and the packet transmission rate of the data packets during the regular interval between the protocol packets offset the delay added by each protocol packet.

4. The method for wireless communication between two devices according to claim 1, wherein the master device and the slave device transmit data using near-field magnetic induction (NFMI).

5. The method for wireless communication between two devices according to claim 1, wherein each protocol packet and each data packet includes an audio sample, such that each sample is transmitted individually on a sample-by-sample basis to reduce the latency in the wireless communication.

6. The method for wireless communication between two devices according to claim 1, the method further comprising: Synchronize the wireless communication between the master device and the slave device, wherein the synchronization includes: The master device transmits protocol packets at regular intervals during the first half of the startup frame; and Data packets and repeating pattern data packets are transmitted alternately during the regular intervals between protocol packets.

7. The method for wireless communication between two devices according to claim 6, the method further comprising: The master device listens for protocol packets from the slave device at regular intervals in the second half of the startup frame.

8. A hearing instrument system, the hearing instrument system comprising: A first hearing device, designated as a primary device and configured to be worn on a user's first ear, comprises: First microphone, First loudspeaker; A first transceiver, configured for wireless communication; and A first processor is configured to execute software instructions stored in a first memory, the software instructions, when executed, causing the first processor to: In the first half of the frame, protocol packets are transmitted to the second hearing instrument at regular intervals; and during the regular intervals between the protocol packets, data packets are transmitted alternately with the second hearing instrument, transmitting in the form of data packets a first channel of audio samples collected at the first microphone, each data packet containing one audio sample, the data packets being transmitted upon collection of each audio sample; and A second hearing device, designated as a slave device and configured to be worn on the user's second ear, the second hearing device comprising: Second microphone, Second speaker; A second transceiver, configured for wireless communication; and A second processor, configured to execute software instructions stored in a second memory, the software instructions causing the second processor to: In the second half of the frame, protocol packets are transmitted to the first hearing instrument at regular intervals; and during the regular intervals between the protocol packets, data packets are transmitted alternately to the first hearing instrument, transmitting in the form of data packets a second channel of audio samples collected at the second microphone, each data packet containing an audio sample, the data packets being transmitted when each audio sample is collected; The number of bits in the data packets is less than the number of bits in the protocol packets, and the average transmission rate is maintained by transmitting the data packets at a data packet period that is faster than the sampling period of the audio samples, such that the average packet period is approximately equal to the sampling period, thereby compensating for the delay added by the protocol packets; The first channel receives audio samples collected at the first microphone; Combining the first channel and the second channel for binaural applications; and The output of the binaural application is coupled to the second speaker.

9. The hearing instrument system of claim 8, wherein the wireless communication comprises near-field magnetic induction (NFMI).

10. The hearing instrument system of claim 8, wherein the binaural application is beamforming.

11. The hearing instrument system of claim 8, wherein the combination includes synchronizing the first channel and the second channel.

12. A non-transitory computer-readable medium comprising instructions stored thereon, the instructions, when executed by a processor of a first hearing instrument, causing the first hearing instrument to perform operations including: The first hearing instrument is designated as the master device and the second hearing instrument as the slave device to transmit data via frames, wherein in the first half of the frame, the first hearing instrument transmits protocol packets to the second hearing instrument, and in the second half of the frame, the second hearing instrument transmits protocol packets to the first hearing instrument; in the first half of the frame, a preamble packet is transmitted to the second hearing instrument, wherein the transmission of the preamble packet causes a first delay corresponding to the time spent transmitting the preamble data of the preamble packet; Following the preamble packet, multiple data packets are transmitted bidirectionally with the second hearing instrument at a rate that compensates for the first delay. The transmission of message packets to the second hearing instrument causes a second delay corresponding to the time taken to transmit the message data of the message packets; Following the message packet, multiple data packets are transmitted bidirectionally with the second hearing instrument at a rate that compensates for the second delay; The transmission of a cyclic redundancy check (CRC) packet to the second hearing instrument causes a third delay corresponding to the time taken to transmit the CRC data of the CRC packet; as well as Following the CRC packet, multiple data packets are transmitted bidirectionally in an alternating manner with the second hearing instrument at a rate that compensates for the third delay. The number of bits in the data packets is less than the number of bits in the protocol packets, including the preamble packets, message packets, and CRC packets. The method of transmitting multiple data packets at a rate that compensates for delay includes maintaining an average transmission rate by transmitting the data packets at a data packet period that is faster than the sampling period of the audio samples, such that the average packet period is approximately equal to the sampling period.

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