Audio stream detection

Abstract

A method includes receiving a first audio stream from a first audio streaming device by an audio receiver device, wherein the first audio stream comprises a plurality of frames, each frame including at least one audio packet time slot for at least one audio packet; and simultaneously receiving the first audio stream from the first audio streaming device, the audio receiver device performs a scan during at least one scan window to search for packets transmitted from a second audio streaming device in a second audio stream. The scan is performed in such a way that at least one audio packet is received in each frame of the first audio stream by preventing the at least one scan window from conflicting with at least one audio packet time slot in each frame of the first audio stream.

Description

[0001] This application is a divisional application of the invention patent application filed on August 14, 2017, with application number 201780093848.5 and title "Audio Stream Detection".

[0002] This application is a continuation of U.S. Patent Application US 16 / 638655, filed February 12, 2020, which is a U.S. national phase application filed pursuant to Section 371 of International Patent Application PCT / EP2017 / 070571, filed August 14, 2017, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a wireless audio receiver device and a wireless audio transmission method. Background Technology

[0004] Isochronous audio streaming between audio devices typically employs frequency hopping, where the transmission frequency changes according to a specific frequency hopping sequence. In such a system, the master device usually periodically sends frequency hopping synchronization (hereinafter referred to as "FHS") packets on a set of frequencies to help slave devices connect to the frequency hopping sequence. Therefore, in order to connect to the frequency hopping sequence used by the master device, the slave device must successfully receive at least one such FHS packet. However, since the slave device is not yet synchronized with the master device that sent the FHS packets during the scanning of these FHS packets, the scanning slave device does not know when or at what frequency the FHS packets are transmitted.

[0005] Typically, FHS packets are transmitted periodically. One known technique for listening for synchronization packets is the so-called "sliding scan" technique, in which the scanning device periodically listens at the frequency of the expected synchronization packets during a scan window. The period length (or periodicity) of the scan window is chosen to be a multiple of the synchronization packet transmission period length, resulting in a relative offset between the scan window and the synchronization packet transmission in each sequential scan cycle. Therefore, after a period of time, the scan window and the synchronization packet transmission will meet in time and frequency at some point. The maximum time interval required for synchronization is also called the "delay." In other words, regardless of the initial phase difference between the scan window and the synchronization packets, there will always be a meeting in time and frequency after the maximum time interval. Typically, the scan window period length is greater than the synchronization packet period length.

[0006] US 8194902 B2 relates to an example of a sliding scan technique in which a hearing instrument synchronizes with the transmitter of a device in a wireless network by adjusting the sum of active and inactive time periods to a duration different from that of a network protocol frame, such that specific time slots in which the transmitter transmits data and the active time periods overlap simultaneously.

[0007] WO 2011 / 098141 A1 relates to another example of a sliding scan technique in which the receiver unit of a hearing instrument synchronizes with the transmission unit of an audio signal source using a TDMA frame structure by periodically listening to specific wake-up periods of beacon packets, wherein the beacon listening period differs from the beacon transmission period by a given percentage.

[0008] WO 2004 / 110099 A2 relates to an audio communication network using frequency hopping, wherein LMP (Link Management Protocol) messages are used for network acquisition, and wherein the location of the time interval for scanning LMP messages is random, such that it can overlap with LMP messages in time after a period of time. Summary of the Invention

[0009] The purpose of this disclosure is to provide a wireless audio transmission method, wherein receiving an audio stream should be enabled when searching for another audio stream. Another purpose is to provide a corresponding audio receiver device.

[0010] According to some embodiments of this disclosure, this objective is achieved by the method defined in claim 1 and the audio receiver device defined in claim 26, respectively.

[0011] While receiving audio packets from a first audio stream from a first audio streaming device, the audio receiver device scans for frequency hopping synchronization (FHS) packets transmitted from a second audio streaming device. This ensures that at least one audio packet is received from the first audio stream per frame by preventing the scanning window from conflicting with the time slots of one or more corresponding audio packets in the first audio stream. Therefore, first-class audio reception quality can be maintained at an acceptable level while allowing the detection of at least one other audio stream.

[0012] Some embodiments are defined in the dependent claims. Attached Figure Description

[0013] Examples of this disclosure are illustrated with reference to the accompanying drawings, in which:

[0014] Figure 1 This is a schematic diagram illustrating an example of a wireless hearing aid system;

[0015] Figure 2 This is an illustration of an example of scanning activity of an audio receiver device used to detect a second audio stream while receiving a first audio stream;

[0016] Figure 3 yes Figure 2 An enlarged illustration of the relationship between the scan window period and the FHS grouping period in the example;

[0017] Figure 4 It is similar to Figure 2 The illustration shows an example using two synchronization channels;

[0018] Figures 5 to 7 This is an illustration of using a single scan window periodically to detect three different periodic FHS groups, where subsequent scan windows are shown within a single FHS group period;

[0019] Figure 8 This is an illustration of an alternative example of scanning activity of an audio receiver device for a second audio stream while receiving a first audio stream.

[0020] Figures 9 to 11 Is with Figures 5 to 7 A similar illustration, however, shows an inappropriate choice of scan window period for three different FHS grouping periodicities;

[0021] Figure 12 This shows the number of scan windows required for periodic detection of FHS packets for a given scan window, based on the FHS packet periodicity; and

[0022] Figure 13 It is similar to Figure 12 The illustration shows, however, another example. Detailed Implementation

[0023] The accompanying drawings are not necessarily drawn to scale. Similarly, for the purpose of discussing some embodiments of this disclosure, some components and / or operations may be separated into different blocks or combined into a single block. Furthermore, although this disclosure can be made in various modifications and alternative forms, specific embodiments are shown by way of example in the accompanying drawings and are described in detail below. However, it is not intended to limit this disclosure to the specific embodiments described. Rather, this disclosure is intended to cover all modifications, equivalents, and alternatives that fall within the scope of this disclosure as defined by the appended claims.

[0024] A "scan window" is the time interval during which an audio receiver device listens for FHS packets. The "scan window length" is the duration of this time interval. Scan windows can repeat periodically; in this case, the "period" is the time interval that repeats after it (one period corresponds to one cycle). Therefore, a "scan window period" is the time interval from, for example, the beginning of one scan window to the beginning of the next scan window, and the "scan window period length" is the duration of this time interval. "Periodic" can be used as a synonym for "period length." These terms are similarly used for the transmission of FHS packets and audio packets.

[0025] The techniques described herein can be embodied in dedicated hardware (e.g., circuitry), programmable circuitry appropriately programmed with software and / or firmware, or a combination of dedicated and programmable circuitry. Therefore, embodiments may include a machine-readable medium on which instructions are stored, which can be used to program a computer (or other electronic device) to perform a process. Machine-readable media may include, but are not limited to, floppy disks, optical disks, optical disk read-only memory (CD-ROM), magneto-optical disks, ROMs, random access memory (RAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic cards or optical cards, flash memory, or other types of media / machine-readable media suitable for storing electronic instructions. In some embodiments, the machine-readable medium is a non-transitory computer-readable medium, wherein non-transitory does not include the propagation of signals. In some embodiments, Figure 1 The equipment execution disclosed in China Figures 2 to 13 Some or all of the operations described in the document.

[0026] Figure 1 This is a block diagram of an example of a hearing device 10 to be worn in one of a user's ears, which is typically used in conjunction with a second hearing device to be worn in the user's other ear to form a binaural hearing system. In some embodiments, the hearing device 10 is a hearing aid such as a RIC (receiver in the ear canal), BTE (behind the ear), ITE (in the ear), ITC (in the ear canal), or CIC (completely in the ear canal) hearing aid. However, the hearing device can also be, for example, a hearing prosthesis, such as a cochlear implant device comprising an implanted cochlear stimulator and an external sound processor, which can be designed as a BTE unit with headphones or an integrated headphone.

[0027] exist Figure 1 In the example, hearing device 10 is a hearing aid that includes a microphone device 12 for capturing audio signals from ambient sound, an audio signal processing unit 14 for processing the captured audio signals, and an electroacoustic output transducer (speaker) 16 for stimulating the user's hearing based on the processed audio signals. In some embodiments, the audio signal processing in unit 14 may include beamforming (in which case, microphone device 12 includes at least two spaced-apart microphones).

[0028] Hearing aid 10 includes a wireless interface 20, which includes an antenna 26 and a transceiver 28. Interface 20 is provided for enabling wireless data exchange between the first hearing aid 10 and external devices 11, 40. For example, hearing aid 10 can be connected to a second hearing aid (e.g., as external device 11) via a wireless link 30 for implementing a binaural hearing assistance system, thereby allowing the hearing aids to exchange audio signals and / or control and status data, such as the current settings of the hearing aids.

[0029] Interface 20 is also provided for exchanging data with at least one other external device via wireless link 30, for example, for receiving audio data streams from an external device acting as an audio source. Such an external device... Figure 1 The numbers 40 and 50 are shown in the middle.

[0030] The hearing device 10 also includes a control unit 38 for controlling the operation of the hearing aid 10, wherein the control unit 38 acts on the signal processing unit 14, the transceiver 28, and the memory 36, which stores data required for the operation of the hearing aid 10 and data required for the operation of the interface 20, such as pairing / network data.

[0031] Hearing device 10 can receive an audio stream from another device 11 via a wireless link 30, and then hearing device 10 acts as an audio receiver device, while the other device 11 acts as an audio streaming device. For this purpose, hearing device 10 must connect to the other device 11 via a suitable wireless protocol with a time-slot frame structure, wherein certain time slots in each frame are dedicated to certain activities; for example, at least one time slot in each frame is used to send audio data packets from the audio streaming device to the audio receiver device. In some embodiments, each audio data packet is sent not just once, but several times, such as three times, to provide some redundancy to avoid loss of audio quality when the audio receiver device fails to receive the audio packet, for example due to interference signals (in which case at least one of two copies will be received, thus effectively avoiding packet loss).

[0032] An audio stream may consist of only audio data, or the audio data of an audio stream may be part of a media stream that includes both audio and video data; for example, an audio stream may also include video data. Typically, an audio stream is broadcast from an audio source to multiple audio receivers. For example, the audio source acts as a broadcast device that sends information unidirectionally to the receiver devices, where the receiver devices cannot provide feedback to the broadcast device about the information, such as whether audio packets were received, or if there is no uplink.

[0033] Typically, audio streaming requires isochronous data streams, which means that audio data flows continuously at a steady rate.

[0034] exist Figure 2A simplified example of this audio streaming process is shown, in which a first audio streamer (e.g., device 11) uses sequential frequency hopping to transmit audio packets three times in each frame R using a fixed sequence of three transmission channels #1, #2, and #3. For example, the first audio packet may be transmitted in channel #1, a first copy of the same audio packet may be transmitted in channel #2, and a second copy of the audio packet may be transmitted in channel #3. The time slots dedicated to audio packet transmission in each frame R are... Figure 2 The middle part is marked as "A".

[0035] Typically, in practice, the frequency hopping sequence becomes more complex when more channels are involved, and it is not fixed but varies according to a pseudo-random sequence known or computable by both connected devices 10 and 11. When two devices are connected, their clocks are synchronized so that they have the same time base, and both know or can compute the frequency hopping sequence. Therefore, audio receiver device 10 knows when the transmission of audio data packets is expected and in which channel this will occur, allowing the audio receiver device to listen during the respective time slot "A" of the corresponding channel. Audio data packets are received by audio receiver device 10 in... Figure 2 The middle is indicated by a vertical arrow.

[0036] In addition to audio data packets, audio streaming devices also send data packets containing information necessary for connecting to the audio streaming device to receive its audio stream. This information includes clock information for clock synchronization and information related to the frequency hopping sequence used by the audio streaming device. Hereinafter, the data packets conveying this information will be referred to as frequency hopping synchronization (FHS) packets; Figure 2 In this context, such FHS packets are marked as "F". In some implementations, FHS packets can be sent periodically, for example once in each frame R or once every nth frame, such that a certain time slot "F" is dedicated to the transmission of FHS packets in each frame or every nth frame.

[0037] Typically, FHS packet transmission does not utilize the full frequency range of the protocol, instead using only subgroups of available channels. Figure 3 In the example, only channel #2 is used for the transmission of FHS packets. For devices not yet connected to an audio streaming device, one or more channels used for transmitting FHS packets are usually also known, and the actual order of these channels (which may be labeled "synchronization channels") can be variable and is then not known to devices wishing to connect to an audio streaming device.

[0038] Typically, the audio streaming device acts as the "master," while the audio receiver device acts as the "slave."

[0039] In order to receive FHS packets, an audio receiver device can listen for FHS packets during certain time windows; such time windows are called "scan windows," and... Figure 2 The symbol is marked "S". However, since the device that wants to connect to the audio streaming device (such a device may be called a "scanning device") is not yet synchronized with the audio streaming device, it does not know when it expects the transmission of FHS packets.

[0040] exist Figure 2 An example is shown where an audio receiver device 10 scans FHS packets from another audio streaming device (i.e., a second audio streaming device 40) while simultaneously receiving audio data packets from a first audio streaming device 11. It is desired that the scanning of the second audio streaming device 40 by the audio receiver device 10 occurs in such a way that the scanning action has little or no impact on the audio quality of the audio stream received from the first audio streaming device 11. To this end, the scanning activity of the audio receiver device 10 is performed in a manner that ensures reception of at least one audio packet per frame of the audio stream from the first audio streaming device 11 by preventing the scanning window from conflicting with the time slot of at least one audio packet per frame of the audio stream from the first audio streaming device 11. An example of this scanning strategy will be discussed in more detail below.

[0041] Once an FHS packet has been received from the second audio streaming device 40, there are several options for how the audio receiver device 10 should react (this occurs when there is a time and frequency overlap between the FHS packet transmitted from the second audio streaming device 40 and the scan window "S" of the audio receiver device 10).

[0042] In some implementations, the audio receiver device can automatically disconnect from the first audio streaming device and connect to a second audio streaming device to receive (second) audio streams from the second audio streaming device instead of (first) audio streams from the first audio streaming device. For example, the audio receiver device can switch from the first audio streaming device to the second audio streaming device only if the received signal strength of the second audio stream is above a given threshold. In some implementations, the audio receiver device can switch from the first audio stream to the second audio stream only if the received signal strength of the second audio stream is higher than that of the first audio stream, such that the receiver device is implemented to always connect to the audio stream with the highest signal strength, which is typically the audio stream from the nearest audio streaming device.

[0043] For example, an audio receiver device can automatically switch from a first audio stream provided by a TV streamer in the living room to a second audio stream provided by a wireless device in the kitchen. Other examples include automatic switching between audio streams provided by different wireless microphones or headsets.

[0044] In some implementations, once the audio receiver device has received FHS packets from the second audio streaming device, it can notify the user, for example, via an appropriate audio signal, enabling the user to perform a gesture to connect the audio receiver device to the second audio streaming device. In other words, the decision to switch from the first audio stream to the second audio stream may not occur automatically, but may be made by the user of the audio receiver device.

[0045] In some implementations, the first audio stream and the second audio stream may use the same protocol, such as a proprietary protocol. In other implementations, the first audio stream and the second audio stream may use different protocols; for example, the first protocol may be a proprietary protocol, and the second protocol may be a standard protocol, such as the Bluetooth protocol.

[0046] exist Figure 2 In the example shown, the second audio streaming device 40 uses the same protocol as the first audio streaming device, wherein FHS packets are sent periodically, for example, once in each frame R. In this case, the periodicity (length or duration of a cycle) of the FHS packet transmission (“T_SYNC”) is equal to the length of frame R; the periodicity (cycle length) of the audio packet transmission is also equal to the frame length, and therefore equal to the length of the FHS packet transmission cycle. The frame length (duration of one frame R) can be, for example, 10 ms.

[0047] In some implementations, in Figure 2 An example of this is shown, in which a scan performed by an audio receiver device occurs during a periodically repeating scan window, the duration of which (“W_SCAN”) is selected such that reception of at least one audio packet per frame of the first audio stream is achieved by preventing the scan window from conflicting with at least one audio packet time slot of the first audio stream, and wherein the periodicity (period length) (“T_SCAN”) of the scan window is selected such that each scan window overlaps with one of the subsequent scan windows when the periodicity of the FHS packet transmission of the second audio stream is taken into account.

[0048] In other words, the "overlap" is visible when two "overlapping" scan windows are "mapped" to the same FHS packet transmission period by shifting the subsequent scan window backward by an appropriate multiple of the FHS packet period length T_SYNC. Mathematically, this mapping uses the "modulo T_SYNC" operation.

[0049] In some implementations, when the overlap between two scanning windows is mapped to the same FHS packet period, it corresponds at least to the duration or length of the start frame delimiter (SFD) of the FHS packet. (Once the SFD of the FHS packet is received by the audio receiver device, which is the case where the SFD falls within one of the scanning windows, the receive window (scanning window) can be automatically extended to receive the complete corresponding packet if a radio chip is configured accordingly. (Alternatively, instead of using the SFD, the address or address code of the packet can be used in some implementations.)

[0050] An example of mapping the scan window S to the same FHS grouping period is as follows: Figure 2 As shown, by shifting scan windows 2 to 5 backward in time by an appropriate multiple of the FHS packet period length T_SYNC, all scan windows (i.e., scan windows in frames 1 to 6 of the audio receiver device) are "mapped" into the first frame (the second scan window is shifted by one FHS packet period, the third scan window is shifted by two FHS packet periods, the fourth scan window is shifted by three FHS packet periods, and so on).

[0051] The scan window period T_SCAN is longer than the FHS packet period T_SYNC (or the audio packet period or frame length, which is in...) Figure 2 In the case where the scan window period is the same in all examples, overlapping of the "mapped" scan window is achieved by choosing a scan window period that is not any multiple of the FHS grouping period; this condition can also be written as: T_SCAN modulo T_SYNC≠0. When the scan window period is less than the FHS grouping period, the multiples of the scan window period do not need to be multiples of the FHS grouping period (T_SCAN*N modulo T_SYNC≠0, where N is an integer).

[0052] It should be noted that when mapped to the same FHS grouping period, two overlapping scan windows do not necessarily have to be two adjacent scan windows. Instead, for example, the scan window pattern can make... Figure 2 The first and second scan windows do not overlap, while the first and fifth scan windows overlap.

[0053] The difference between the scan window period T_SCAN and the FHS grouping period T_SYNC causes the subsequent scan window to shift relative to the FHS grouping period, such as... Figure 3 As shown, an example is illustrated with a 10ms FHS packet period and a 12ms scan window period. This results in a relative offset T_SHIFT of 2ms for the next scan window (derived from 12ms minus 10ms = 2ms, or T_SHIFT = T_SCAN modulo T_SYNC = 12ms modulo 10ms = 2ms); the scan window duration W_SCAN is 3ms. This results in an overlap of 1ms between the first and second scan windows (when the second scan window is mapped into the first FHS packet period by shifting it backward by 1*T_SYNC = 10ms).

[0054] The typical duration of the start frame delimiter is 40 μs, which is a duration of 5 bytes at a rate of 1 Mbps or a duration of 10 bytes at a rate of 2 Mbps. Therefore, as in Figure 4 As in the example, a 1ms overlap would actually be too long (for clarity in the accompanying diagram). Figure 3 and Figure 4 (This relatively large overlap was used).

[0055] exist Figure 2 and Figure 3 In the example, a full duration of 10ms is covered after 5 consecutive scan windows, which is the duration of one audio frame R (or one FHS packet period), so that an FHS packet will fall within the scan window at the latest after five scan window periods S (corresponding to six audio frames R) and can be received; therefore, the delay in this case is 5 * 12ms = 60ms (which depends on the relative movement between the frame of the audio receiver device and the frame of the second audio streaming device in which the FHS packet will actually be received in the scan window).

[0056] Although Figure 2 and Figure 3 In the illustration, for the sake of simplicity, the periodicity of the scan window is not much larger than the periodicity of the audio frame. In reality, the periodicity of the scan window will be much larger than the audio periodicity so that only a small amount of current is consumed for scanning. For example, with a scan window length of 3ms, the scan window period can be chosen to be 102ms. In this case, the scan duty cycle will be 3 / 102 = 2.9%. In this case, since five scan window periods will be needed to cover a complete 10ms audio frame, the delay (maximum detection delay) is 5 * 102ms = 510ms.

[0057] Despite Figure 2In the example, only a single channel / frequency is used to transmit FHS packets, but in some implementations, multiple channels can be used to provide greater robustness against interference. Typically, the transmission of FHS packets and the periodic scanning within each channel can be considered as parallel and independent activities. Figure 4 An example is shown where a second audio streaming device sends FHS packets in two different channels 2 and 4 in each frame, while an audio receiver device performs a scan in parallel on the two channels.

[0058] In some implementations, such as Figure 2 As shown, an audio receiver device may simply scan to find a single second audio stream with a fixed and known FHS packet periodicity. However, in some implementations, the audio receiver device may scan to find a second audio stream that may have at least two different FHS packet periodicities (e.g., a protocol used by the second audio streaming device may allow selection of FHS packet periodicities from a different set of values), or the audio receiver device may scan to find at least two other known audio streams with different FHS packet periodicities (e.g., a second and a third audio stream).

[0059] In the presence of a set of different FHS grouping periods, the scan window periodicity is selected in such a way that the aforementioned “overlap” condition for a single FHS grouping periodicity applies to each FHS grouping periodicity.

[0060] Examples of scan window periodicity that satisfy the "overlap" condition for several FHS grouping periodicities are shown in Figures 5 to 7 As shown in the figure, a method similar to... Figure 2 The scanning process involves a 3ms scan window length W_SCAN and a 22ms scan window period T_SCAN used to scan and find the period T_SYNC, which is 10ms. Figure 5 ), 20ms Figure 6 ) and 50ms Figure 7 FHS grouping. In Figures 5 to 7The diagram illustrates single FHS grouping periods of length 10ms, 20ms, and 50ms, respectively, to which 5, 10, and 25 scan windows are “mapped”, respectively. The nth scan window is indicated at vertical position n and has a horizontal dimension corresponding to its 3ms length / duration. It can be seen that for all three FHS grouping periods, there is paired overlap between two 1ms scan windows. With FHS grouping periods of 10ms and 20ms (shorter than the 22ms scan window period), there is always overlap between adjacent scan windows. However, with an FHS grouping period of 50ms, which is longer than the 22ms scan window period, the overlapping scan windows are not adjacent.

[0061] Therefore, by using a pair of scan window durations (3ms) and scan window periods (22ms), it is possible to cover three different FHS grouping periods of 10ms, 20ms, and 50ms, respectively.

[0062] exist Figure 2 In the example, a 3ms scan window length allows for the reception of at least two of the three audio packets per frame (audio packet slots that conflict with the scan window are in...). Figure 2 (Marked with "X", see audio frames 1, 2, 5, and 6). Therefore, even if one of the two audio receive slots in each frame that does not conflict with the scan window fails to result in successful reception of an audio packet, there will still be a second opportunity in each frame to receive a copy of the audio while scanning for FHS packets of the second audio stream. Having a second opportunity to receive a copy of the audio packet in each frame can provide robust audio reception in the event of packet loss due to, for example, interference. In some implementations, good audio quality can be obtained if the audio frame error rate is at most 1%. With two reception opportunities, a packet error rate as high as 10% can be tolerated because at such a packet error rate, the probability of losing both the first and second copies is 10% * 10% = 1%.

[0063] In some implementations, such as Figure 8 The example illustrates that choosing the duration of the scan window to cover the entire FHS packet period ensures that, in principle, a single scan window is sufficient to safely receive an FHS packet—regardless of the relative phase of the audio receiver device frame with respect to the frames of the second audio stream. Figure 8In the example shown, the frame length (or audio packet periodicity) of the first audio stream is 4.0 ms, the FHS packet periodicity of the second audio stream is also 4.0 ms, the duration of the audio packet reception slot is 0.4 ms, and the duration of the scan window W_SCAN is 4.1 ms. Furthermore, the phase and duration of the scan window are chosen such that at least one audio packet per frame of the first audio stream is received by preventing conflicts between the scan window and at least one audio packet slot per frame of the first audio stream.

[0064] Therefore, if the audio packet reception in the first audio reception time slot is successful, the scanning window will scan in a certain frame (e.g., frame #2 and ...). Figure 8 It begins after the first audio reception slot in the first frame, and at least in the next frame ( Figure 8 In the example, frame #3) terminates before the start of the last audio receive slot. This ensures that even in frames where scanning activity exists ( Figure 8 Frames 2 and 3 in the image (frames #2 and #3) can also achieve the reception of at least one audio packet per frame: in frame #2, an audio packet has been successfully received (otherwise the scanning activity would not start from frame #2), and then in frame #3, there is at least a chance to receive an audio packet in the last audio reception slot of frame #3. In some implementations, such as Figure 8 As shown in the example, the scanning window is terminated no later than the start of the second audio packet time slot in the next frame (frame #3) to allow reception of at least two audio packets in the next frame (frame #3); this improves audio quality because, for example, if reception fails in the last audio time slot of frame 3 (e.g., due to interference), there will be an opportunity to receive audio packets in the second audio reception time slot of frame #3.

[0065] In some implementations, the scan window duration is selected such that it is at least the periodicity T_SYNC of the FHS packets of the second audio stream plus the length of the start frame delimiter of the FHS packets (as described above, in the case where the audio chip is correspondingly indicated, the reception of the SFD of the FHS packets is sufficient to receive the complete FHS packets so that the scan window continues after the reception of the SFD until the complete packets are received).

[0066] exist Figure 8 In the example, the duration of the audio transmission and reception time slots is 400 μs, while the duration of the audio packet itself is 164 μs. This is because the last part of a time slot in a frequency-hopping system is typically used to change the radio frequency, not for radio transmission. Therefore, the scanning window may have already started some time before the end of the first audio reception time slot, for example, 100 μs before the end of the time slot, because it is already clear at this point that the audio packet has been successfully received.

[0067] For simplicity, Figure 8 Only a single FHS packet channel is shown in the image, while... Figure 4 In the example, there may be more than one FHS packet channel.

[0068] In some implementations, it is repeated periodically. Figure 8 The example scan window is selected with a periodicity to correspond to the maximum acceptable connection delay for the detection of the second audio stream. For example, a scan window period of 2.5 s would provide a scan duty cycle overhead of 4.1 ms / 2500 ms = 0.16%; in radio receive mode with a current consumption of 6.5 mA, this would result in a current consumption overhead of 0.0016 * 6500 mA = 10 mA. As mentioned above, the selection of the scan window period is a trade-off between the detection delay of the second audio stream and the energy used to search for the second audio streaming device.

[0069] and Figure 2 and Figure 3 The main difference between the examples lies in the fact that, in principle, a single scan window is sufficient to receive one FHS packet, while... Figure 2 and Figure 3 The example requires a certain number of scan windows, such as 5.

[0070] Figure 8 The principle shown is particularly applicable to the case where FHS packets are sent periodically for a period not longer than the duration of the scan window (the upper limit of the scan window duration is determined by the periodicity, length, and distribution of the audio slots in the slot frames of the first audio stream).

[0071] In some implementations, the duration and start point of the scanning window are selected to receive FHS packets from the second audio streaming device, such as... Figure 8 As shown, the scanning window can also be periodically repeated to scan for another audio streaming device (a third audio streaming device) with an FHS packet periodicity different from that of the second audio streaming device, wherein, by using about Figure 2 and Figure 3 The principle shown is used to select the periodicity of the scan window (in order to obtain sufficient "overlap" of "mapped" scan windows, where a certain number of "mapped" scan windows cover the entire FHS packet period). In other words, Figure 2 and Figure 3 The principle shown and Figure 8 The principles shown can be combined.

[0072] In some implementations, the audio receiver device and the first and second audio streaming devices can use the same proprietary protocol, while the third audio streaming device can use a standard protocol such as Bluetooth. Standard protocols allow for various values ​​of the FHS packet period T_SYNC; for example, the FHS packet period can be a multiple of 1.25 ms (twice the Bluetooth slot duration). Therefore, in Figure 8 In the example, where the scan window duration W_SCAN is 4.1 ms, all FHS packet periods shorter than the scan window duration minus the SFD duration (which could be, for example, 40 μs) (i.e., 4.060 ms) are covered. Therefore, FHS packet periods of 1.25 ms, 2.5 ms, and 3.75 ms will be covered by a single scan window with a duration of 4.1 ms.

[0073] However, for larger values, an appropriate periodicity must be chosen. For example, a "brute-force" overlay search across all values ​​of the scan window periodicity T_SCAN (which is a multiple of the audio periodicity T_AUDIO of the first audio streaming device = 4ms) reveals that a scan window periodicity of 964ms covers all FHS grouped periodicities from the set {1.25ms, 2.5ms, ..., 100ms}. The average current consumption obtained from this scan activity is 4.1ms / 964ms * 6500μA = 28μA.

[0074] This coverage search can be performed by calculating, for each FHS packet period value T_SYNC and for a number of scan window period values ​​T_SCAN, where consecutive scan windows will end within the FHS packet period. For each scan window periodity value, the number of consecutive scan windows required to cover the entire FHS packet period is recorded. If the FHS packet period cannot be completely covered after a certain number of consecutive scan windows (e.g., 100 consecutive scan windows), then that scan window periodity value is not considered a candidate value. As discussed above, this can occur when an integer multiple of the scan window period is divisible by the FHS packet period (mathematically, this condition is: T_SCAN * N_SCAN modulo T_SYNC = 0, where the number of scan windows N_SCAN is an integer). At the end of the search, a list of suitable candidate values ​​for the scan window periodity is obtained. From this list, the scan window periodity value that is closest to the target scan window periodity and provides the minimum number of scan windows required to receive FHS packets can be selected.

[0075] The periodicity of the target scan window can be determined from the allowable power consumption of the radio receiver, which can be dedicated to the scan activity. In this regard, the overall power consumption of the audio receiver device and the flow detection delay performance resulting from the periodicity of the target scan window must be considered. Typically, a higher allowable power consumption dedicated to the scan activity results in a lower (shorter) delay, necessitating a trade-off. In some implementations, the detection delay should not exceed a few seconds. Acceptable detection delay is determined by the availability criteria of the audio receiver device. According to some implementations, the detection delay should be less than 10 seconds, for example, less than 3 seconds or less than 1 second. Based on the example above, a scan window duration of 4.1 ms and a scan window periodicity of 964 ms will result in an average power consumption of 28 μA for the radio receiver dedicated to the scan activity. The power consumption of the scan activity leads to a reduction in the battery life of the audio receiver device. For example, in the case of a zinc-air battery with a current capacity of 130 mAh and an average current of 0.8 mA, the lifespan will be reduced from 162.5 h to 157 h, a reduction of approximately 3%.

[0076] Figure 12 The graph illustrates the performance of the scanning activity discussed above (i.e., the number of scan windows required), where the scan window duration is 4.1 ms and the scan window periodicity is 964.0 ms, which is based on the FHS grouping periodicity (more precisely, for a set of multiples of the Bluetooth time base from 1.25 ms to 100 ms). Figure 12 The dashed line in the figure represents the lower limit of the number of scan windows required, which is given by subtracting (the scan window duration W_SCAN minus the duration T_SFD of the start frame delimiter) from the FHS grouping periodicity T_SYNC. The resulting detection delay is given by the following formula: T_SCAN*[1+N_SCAN], which is the time required to execute all the required N_SCAN scan windows (T_SCAN is the periodicity of the scan window). For example, for T_SYNC = 10ms and N_SCAN = 5, the resulting detection delay is 5784ms.

[0077] from Figure 12 As can be seen, the performance of the above process is almost optimal for FHS grouping periodicity as high as 11ms, while for larger FHS grouping periodicity values, the number of scan windows required can deviate from the optimal value.

[0078] exist Figures 9 to 11 The text illustrates the consequences of an inappropriate choice of scan window periodicity (i.e., for T_SCAN = 960ms). More specifically... Figures 9 to 11 Is with Figures 5 to 7A similar figure shows the scan window mapped to a single FHS packet period, where the scan window duration is 4.06 ms and the FHS packet period T_SYNC is 7.50 ms. Figure 9 ), 22.5ms Figure 10 ) and 25.00ms Figure 11 As can be seen, in these cases, the scan window does not completely cover the FHS packet cycle.

[0079] The ideas discussed above can also be applied to situations where the first audio stream uses a standard protocol such as Bluetooth instead of... Figure 8 The example illustrates a system with a proprietary protocol, wherein the second (and third) audio streaming device can use either a standard protocol or a proprietary protocol. For example, the first audio streaming device could use a standard protocol with audio periodicity / frame length of 3.75 ms to send an audio stream. Again, assuming the scan window can begin 100 μs before the end of the slot for successfully receiving a copy of the first audio packet and end before the start of the second audio copy in the next audio frame, the duration of the scan window might be 0.1 ms plus 3.75 ms = 3.85 ms. In that case, as... Figure 13 As shown, the appropriate value for the FHS grouping periodicity to cover all FHS grouping periods from 1.25ms to 100ms (more precisely, all multiples of 1.25ms up to 100ms) would be 896.25ms. Figure 13 Is with Figure 12 A similar figure is given, in which the number of scan windows required for all FHS grouping periods is given, which are multiples of 1.25 ms up to 100 ms.

[0080] In some implementations, the FHS packet can be implemented as part of an audio packet that explicitly or implicitly includes information required to connect to the audio stream. In other words, in some implementations, the FHS packet can be part of an audio packet; in other implementations, the FHS packet can be separate from the audio packet, such as... Figures 2 to 4 and Figure 8 As shown.

[0081] As discussed above, FHS packets can be sent periodically, where the periodicity can be defined by a proprietary protocol, or in the case of the Bluetooth protocol, it can be a multiple of a 1.25ms time base value.

[0082] However, in some implementations, FHS packets can be transmitted on a random time base, such that, for example, the time interval between the transmission of an FHS packet and the transmission of a subsequent FHS packet is randomized within a given range, allowing the time interval to be selected from a minimum time to a maximum time via a random process. Examples of random packet transmission can be found in Bluetooth Low Energy advertisements.

[0083] The phrases “in some embodiments,” “according to some embodiments,” “in the illustrated embodiments,” and “in other embodiments” generally mean that the specific feature, structure, or characteristic following the phrase is included in at least one embodiment of this disclosure, and may be included in more than one embodiment. Furthermore, such phrases do not necessarily refer to the same embodiment or different embodiments.

[0084] The detailed description of examples of this disclosure above is not intended to be exhaustive or to limit this disclosure to the precise form described above. Although specific examples of this disclosure have been described above for illustrative purposes, various equivalent modifications can be made within the scope of this disclosure, as will be appreciated by those skilled in the art. For example, while procedures or blocks are programmed in a given order, alternative implementations may execute routines having steps in a different order, or employ systems having blocks, and some procedures or blocks may be deleted, moved, added, subdivided, combined, and / or modified to provide alternatives or sub-combinations. Each of these procedures or blocks can be implemented in various different ways. Moreover, although procedures or blocks are sometimes shown as being executed sequentially, these procedures or blocks may alternatively be executed or implemented in parallel, or may be executed at different times. Additionally, any specific figures indicated herein are merely examples: alternative implementations may employ different values ​​or ranges.

Claims

1. An audio transmission method, comprising: A first audio stream is received from a first audio streaming device via an audio receiver device, wherein the first audio stream comprises a plurality of frames, each of the plurality of frames comprising at least one audio packet time slot for at least one audio packet; and While receiving the first audio stream from the first audio streaming device, the audio receiver device performs a scan during at least one scanning window to look for packets sent from the second audio streaming device in the second audio stream; The scanning is performed in such a way that at least one audio packet is received in each frame of the first audio stream by preventing the at least one scanning window from conflicting with at least one audio packet time slot in each frame of the first audio stream. The scanning is performed during a scanning window whose duration (W_SCAN) and phase are selected such that at least one audio packet is received from the first audio stream per frame by preventing the scanning window from conflicting with at least one audio packet slot of the first audio stream, and wherein if the reception in that slot is successful, the scanning window begins after the first audio reception slot in a frame, and the scanning window terminates no later than the start of the last audio reception slot of the next frame.

2. The method according to claim 1, wherein, The packets are sent periodically, and the duration (W_SCAN) of the scan window is at least the period length (T_SYNC) of the packet transmission plus the length of the start frame delimiter of the packet.

3. The method according to claim 1, wherein, Each audio packet of the first audio stream is transmitted at least three times per frame, and the duration (W_SCAN) of the scan window is selected such that it terminates no later than the start of the second audio packet slot in the next frame, so as to enable the reception of at least two audio packets from the first audio stream in the next frame.

4. The method according to claim 3, wherein, The scanning window is repeated with a cycle length (T_SCAN) that is selected to correspond to the maximum acceptable connection delay for detection with respect to the second streaming device.

5. The method according to claim 1, wherein, The scanning window is repeated periodically to additionally scan for packets periodically transmitted from the third audio streaming device in the third audio stream, wherein the packet period length (T_SYNC) of the third audio stream is different from the packet period length of the second audio stream, and wherein the period length (T_SCAN) of the scanning window is selected such that the first scanning window and the second scanning window of the first scanning window period are mapped to the same packet period of the third audio stream by shifting the second scanning window of the subsequent second scanning window period backward by an appropriate multiple of the packet period length of the third audio stream.

6. The method according to claim 5, wherein, The first scan window and the second scan window overlap at least by the duration of the start frame delimiter of the third audio stream group.

7. The method according to claim 5, wherein, For the third audio stream, there exists a set of different group period lengths (T_SYNC), wherein the period length of the scan window is selected such that for each group period length in the set of group period lengths, the condition that the first scan window and the second scan window partially overlap is satisfied.

8. The method according to claim 7, wherein, The period length (T_SCAN) of the scan window is a multiple of the audio group period length (T_AUDIO) of the second audio stream, and wherein the period length of the scan window is selected such that the multiple of the period length of the scan window is not a multiple of any of the group period lengths (T_SYNC) in the set.

9. An audio transmission method, comprising: A first audio stream is received from a first audio streaming device via an audio receiver device, wherein the first audio stream comprises a plurality of frames, each of the plurality of frames comprising at least one audio packet time slot for at least one audio packet; and While receiving the first audio stream from the first audio streaming device, the audio receiver device performs a scan during at least one scanning window to look for packets sent from the second audio streaming device in the second audio stream; The scanning is performed in such a way that at least one audio packet is received in each frame of the first audio stream by preventing the at least one scanning window from conflicting with at least one audio packet slot of each frame of the first audio stream. The scanning occurs during a periodically repeating scanning window whose duration (W_SCAN) is selected such that at least one audio packet is received from each frame of the first audio stream by preventing the scanning window from conflicting with at least one audio packet slot of the first audio stream. Packets of the second audio stream are periodically transmitted. The period length (T_SCAN) of the scanning window is selected such that the first scanning window and the second scanning window of the first scanning window period partially overlap when the first scanning window of the first scanning window period is mapped to the same packet period by shifting the second scanning window of the subsequent second scanning window period backward by an appropriate multiple of the packet period length.

10. The method according to claim 9, wherein, The period length (T_SCAN) of the scan window is longer than the group period length (T_SYNC), and the period length (T_SCAN) of the scan window is different from any multiple of the group period length.

11. The method according to claim 9, wherein, The first scan window and the second scan window overlap by at least the duration of the start frame delimiter of the group.

12. The method according to claim 9, wherein, Each scan window cycle contains a single scan window.

13. The method according to claim 9, wherein, Each audio packet of the first audio stream is sent at least twice per frame, and the duration of the scan window (W_SCAN) is selected such that at least one audio packet can be received from each frame of the first audio stream.

14. The method according to claim 13, wherein, Each audio packet of the first audio stream is sent at least three times per frame, and the duration of the scan window (W_SCAN) is selected such that at least two audio packets can be received from each frame of the first audio stream.

15. An audio transmission method, comprising: A first audio stream is received from a first audio streaming device via an audio receiver device, wherein the first audio stream comprises a plurality of frames, each of the plurality of frames comprising at least one audio packet time slot for at least one audio packet; and While receiving the first audio stream from the first audio streaming device, the audio receiver device performs a scan during at least one scanning window to look for packets sent from the second audio streaming device in the second audio stream; The scanning is performed in such a way that at least one audio packet is received in each frame of the first audio stream by preventing the at least one scanning window from conflicting with at least one audio packet time slot in each frame of the first audio stream. The method further includes: Using frequency hopping, the audio receiving device wirelessly connects to the first audio streaming device via a first protocol; and Frequency hopping is used to wirelessly connect the audio receiving device to the second audio streaming device via a second protocol.

16. The method according to claim 15, wherein, The group includes a frequency hopping synchronization group, which is configured to achieve synchronization with the frequency hopping sequence of the second audio streaming device.

17. An audio receiver device configured to: Receive a first audio stream from a first audio streaming device, wherein, The first audio stream includes a plurality of frames, each of the plurality of frames including at least one audio packet slot for at least one audio packet; and While receiving the first audio stream from the first audio streaming device, a scan is performed during at least one scanning window to look for packets sent from the second audio streaming device in the second audio stream; The scanning is performed in such a way that at least one audio packet is received in each frame of the first audio stream by preventing the at least one scanning window from conflicting with at least one audio packet time slot in each frame of the first audio stream. The scanning is performed during a scanning window whose duration (W_SCAN) and phase are selected such that at least one audio packet is received from the first audio stream per frame by preventing the scanning window from conflicting with at least one audio packet slot of the first audio stream, and wherein if the reception in that slot is successful, the scanning window begins after the first audio reception slot in a frame, and the scanning window terminates no later than the start of the last audio reception slot of the next frame.

18. The audio receiver device according to claim 17, wherein, The audio receiver device is a hearing aid, a hearing prosthesis, a headset, or a headset.

19. A hearing aid system, comprising: Audio receiver device; First audio streaming device; Second audio streaming device; The audio receiver device is configured to: Receive a first audio stream from the first audio streaming device, wherein the first audio stream comprises a plurality of frames, each of the plurality of frames comprising at least one audio packet time slot for at least one audio packet; and While receiving the first audio stream from the first audio streaming device, the audio receiver device performs a scan during at least one scanning window to look for packets sent from the second audio streaming device in the second audio stream; The scanning is performed in such a way that at least one audio packet is received in each frame of the first audio stream by preventing the at least one scanning window from conflicting with at least one audio packet time slot in each frame of the first audio stream. The scanning is performed during a scanning window whose duration (W_SCAN) and phase are selected such that at least one audio packet is received from the first audio stream per frame by preventing the scanning window from conflicting with at least one audio packet slot of the first audio stream, and wherein if the reception in that slot is successful, the scanning window begins after the first audio reception slot in a frame, and the scanning window terminates no later than the start of the last audio reception slot of the next frame.

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