Method and device for bluetooth low energy data broadcasting

Abstract

An operation method of a sink electronic device according to an embodiment of the present disclosure may comprise the steps of: receiving, from a source electronic device, control information for a broadcast isochronous stream (BIS) connection with the source electronic device; receiving a packet from the source electronic device in a first sub-event within a BIS event configured on the basis of the control information; receiving the packet from the source electronic device in a second sub-event within the BIS event; receiving the packet from the source electronic device in a third sub-event within the BIS event; and comparing, at a bit level, the packet received in the first sub-event, the packet received in the second sub-event, and the packet received in the third sub-event to detect a bit error, and performing combining for recovering the bit error.

Description

Method and device for Bluetooth low energy data broadcasting

[0001] The present disclosure relates to a method of an electronic device performing a broadcast isochronous stream (BIS) service based on limited resources.

[0002] The Internet is evolving from a human-centric network where humans create and consume information to an Internet of Things (IoT) network where information is exchanged and processed between distributed components such as objects. The Internet of Everything (IoE) technology, which combines IoT technology with big data processing technology through connections to cloud servers, is also emerging. To implement the IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recently, technologies such as sensor networks for connecting objects, Machine-to-Machine (M2M) communication, and Machine-Type Communication (MTC) are being researched.

[0003] In an IoT environment, intelligent IT (Internet Technology) services can be provided that collect and analyze data generated from connected objects, creating new value in human life. IoT, through the convergence and integration of existing IT (information technology) technologies with various industries, can be applied to fields such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] LE (low energy) electronic devices with Bluetooth Core Version 5.2 or later can support BLE audio services through BIS (broadcast isochronous stream) or CIS (connected isochronous stream) methods.

[0005] BLE audio-based BIS services are primarily used in video / audio electronic devices accessible to multiple users, and can be used for long-term audio / video services for unspecified audiences. Recently, the use of BLE audio services via BIS or CIS is expanding, with the goal of simultaneously providing audio services to a small group of users, rather than an unspecified number of users, on devices such as TVs and mobile electronic devices.

[0006] However, since the BIS source electronic device performs repetitive audio data transmission and periodic advertising, and the BIS sink electronic device does not transmit feedback (ACK / NACK) on whether audio data has been received, there is a growing need for a method to improve the packet error rate (PER) in the BIS service.

[0007] The present disclosure proposes a method for broadcasting reliable BLE audio data.

[0008] According to one embodiment, a method for operating a sink electronic device in a wireless communication system may include: receiving control information for a broadcast isochronous stream (BIS) connection with a source electronic device from the source electronic device; receiving a packet from the source electronic device in a first sub-event within a BIS (broadcast isochronous stream) event established based on the control information; receiving the packet from the source electronic device in a second sub-event within the BIS event; receiving the packet from the source electronic device in a third sub-event within the BIS event; and comparing the packet received in the first sub-event, the packet received in the second sub-event, and the packet received in the third sub-event at a bit level to detect a bit error and performing combining to recover the bit error.

[0009] According to one embodiment, a sink electronic device in a wireless communication system includes a transceiver; and a processor. The processor may receive control information for a broadcast isochronous stream (BIS) connection with a source electronic device from the source electronic device. The processor may receive a packet from the source electronic device in a first sub-event within a broadcast isochronous stream (BIS) event set based on the control information. The processor may receive the packet from the source electronic device in a second sub-event within the BIS event. The processor may receive the packet from the source electronic device in a third sub-event within the BIS event. The processor may compare the packet received in the first sub-event, the packet received in the second sub-event, and the packet received in the third sub-event at a bit level to detect a bit error and perform combining to recover the bit error.

[0010] A method and device according to one embodiment of the present disclosure can broadcast reliable BLE audio data.

[0011] Additionally, the method and device according to one embodiment of the present disclosure can increase the probability of successful packet reception by a sink electronic device.

[0012] FIG. 1 illustrates a system including a plurality of electronic devices according to one embodiment of the present disclosure.

[0013] FIG. 2 is a diagram illustrating a process in which a plurality of electronic devices perform at least one of a CIS connection and a BIS connection according to one embodiment of the present disclosure.

[0014] FIG. 3 illustrates an example of a plurality of electronic devices performing communication via a CIS method according to one embodiment of the present disclosure.

[0015] FIG. 4 illustrates another example of a plurality of electronic devices communicating via a CIS method according to one embodiment of the present disclosure.

[0016] FIG. 5 illustrates an example of a plurality of electronic devices performing communication via a BIS method according to one embodiment of the present disclosure.

[0017] FIG. 6 is a diagram for explaining a packet receiving operation of a BIS sink device according to one embodiment of the present disclosure.

[0018] FIG. 7 is a diagram for explaining a bit-level error recovery method of a BIS sink device according to one embodiment of the present disclosure.

[0019] FIG. 8 is a diagram for explaining the effect of a bit-level error recovery method according to one embodiment of the present disclosure.

[0020] FIG. 9 is a diagram for explaining the effect of a bit-level error recovery method according to one embodiment of the present disclosure.

[0021] FIG. 10 illustrates an example of a plurality of electronic devices performing communication via the BIS method and the ACL method according to one embodiment of the present disclosure.

[0022] FIG. 11 illustrates a configuration of a source device according to one embodiment of the present disclosure.

[0023] FIG. 12 illustrates a configuration of a sink device according to one embodiment of the present disclosure.

[0024] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the attached drawings. In describing an embodiment of the present disclosure, if a detailed description of a related known function or configuration is determined to unnecessarily obscure the gist of an embodiment of the present disclosure, such detailed description will be omitted. The terms described below are defined in consideration of the functions of an embodiment of the present disclosure, and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the contents throughout this specification.

[0025] It should be noted that the technical terms used in this specification are merely used to describe specific embodiments and are not intended to limit the embodiments of the present disclosure. Alternatively, unless specifically defined otherwise herein, the technical terms used in this specification should be interpreted as having a meaning generally understood by those skilled in the art to which the present disclosure pertains, and should not be interpreted in an excessively broad or narrow sense. Alternatively, if a technical term used in this specification is an incorrect technical term that does not accurately express the spirit of the present disclosure, it should be replaced with a technical term that can be correctly understood by a person skilled in the art. Alternatively, general terms used in an embodiment of the present disclosure should be interpreted as defined in a dictionary or according to the context, and should not be interpreted in an excessively narrow sense.

[0026] Alternatively, the singular expressions used herein include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consist of" or "comprises" should not be construed to necessarily include all of the various components or various operations described in the specification, and should be construed to mean that some of the components or some of the operations may not be included, or that additional components or operations may be included.

[0027] Alternatively, terms including ordinal numbers, such as "first," "second," etc., used herein may be used to describe various components, but the components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present disclosure, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0028] When a component is referred to as being "connected" or "connected" to another component, it may be directly connected or connected to that other component, but there may also be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0029] Hereinafter, an embodiment according to the present disclosure will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers and redundant descriptions thereof will be omitted. Alternatively, when describing an embodiment of the present disclosure, if a detailed description of a related known technology is determined to obscure the gist of the present disclosure, the detailed description thereof will be omitted. Alternatively, it should be noted that the attached drawings are only intended to facilitate easy understanding of the spirit of the present disclosure and should not be construed as limiting the spirit of the present disclosure by the attached drawings. The spirit of the present disclosure should be construed to extend to all modifications, equivalents, and substitutes other than those shown in the attached drawings.

[0030] FIG. 1 illustrates a system including a plurality of electronic devices according to one embodiment of the present disclosure.

[0031] LE electronic devices with Bluetooth Core Version 5.2 or later can support BLE audio services via BIS (broadcast isochronous stream) or CIS (connected isochronous stream) methods.

[0032] The CIS method is an acknowledgment protocol, allowing a CIS sink device to send feedback on data transmitted by a CIS source device. CIS is a unicast method, allowing one-to-one communication between a CIS source device and a CIS sink device.

[0033] BIS is a non-acknowledgment protocol, making it difficult to ensure reliability during data transmission and reception. To address this, the BIS source device can retransmit the same data multiple times to ensure reliability during data transmission and reception. BIS is a broadcast protocol, allowing the BIS source device to broadcast data to multiple BIS sink devices.

[0034] Referring to FIG. 1, a first electronic device (100) functions as a CIS source device or a BIS source device and can transmit (or broadcast) data to at least one sink device. The second electronic device (110) to the seventh electronic device (160) function as a CIS sink device or a BIS sink device and can receive data transmitted (or broadcast) from the source device. For convenience of explanation, FIG. 1 illustrates one source device and six sink devices, but the technical idea of ​​the present disclosure is not limited thereto, and the number of source devices and / or sink devices may be implemented in various ways.

[0035] For example, the first electronic device (100) may be implemented as a portable communication device (e.g., a smartphone or a Bluetooth speaker) and may transmit (or broadcast) audio data via BLE. The second electronic device (110) and the third electronic device (120) may be implemented as a pair of wireless earphones worn on the user's left and right ears, respectively, and may receive audio data transmitted (or broadcasted) from the first electronic device (100). The fourth electronic device (130) and the fifth electronic device (140) may be implemented as a pair of wireless earphones worn on the user's left and right ears, respectively, and may receive audio data transmitted (or broadcasted) from the first electronic device (100). The sixth electronic device (150) and the seventh electronic device (160) may be implemented as a pair of wireless earphones worn on the user's left and right ears, respectively, and may receive audio data transmitted (or broadcasted) from the first electronic device (100).

[0036] For example, each of the second electronic device (110) to the seventh electronic device (160) may operate as an independent sink device and receive audio data transmitted (or broadcasted) from the first electronic device (100).

[0037] The first electronic device (100) can transmit (or broadcast) configuration information necessary for the second electronic device (110) to the seventh electronic device (160) to receive data, respectively. Each of the second electronic device (110) to the seventh electronic device (160) can receive data based on the configuration information transmitted (or broadcast) by the first electronic device (100).

[0038] FIG. 2 is a diagram illustrating a process in which a plurality of electronic devices perform at least one of a CIS connection and a BIS connection according to one embodiment of the present disclosure.

[0039] Source and sink devices can establish connections to an ACL (asynchronous connection-oriented logical transport) link for Bluetooth communication. ACL links are asynchronous communications without reserved time slots, perform packet retransmission for reliability, and can be primarily used for data transmission.

[0040] <Case 1 - 품질 우선>

[0041] When prioritizing the quality of transmission and reception of data (or audio data), the source device can establish a CIS connection with each of multiple sink devices (sink-1, sink-2, sink-3) and transmit and receive data through unicast communication.

[0042] Referring to FIG. 2, in operation 211, a source device (source) and a first sink device (sink-1 (primary)) can perform at least one operation for connecting an ACL link. In operation 212, the source device (source) and the first sink device (sink-1 (primary)) can transmit and receive data and feedback on the data through a CIS connection. In operation 213, the source device (source) and a second sink device (sink-2 (secondary)) can perform at least one operation for connecting an ACL link. In operation 214, the source device (source) and the second sink device (sink-2 (secondary)) can transmit and receive data and feedback on the data through a CIS connection. In operation 215, the source device (source) and a third sink device (sink-2 (secondary)) can perform at least one operation for connecting an ACL link. In operation 216, the source device (source) and the third sink device (sink-2 (secondary)) can transmit and receive data and feedback on the data via the CIS connection.

[0043] <Case 2 - 지연 시간 최소화>

[0044] When minimizing the delay time for transmitting and receiving data (or audio data) is given priority, a source device (source) can establish a BIS connection with each of multiple sink devices (sink-1, sink-2, sink-3) and transmit and receive data through broadcast communication.

[0045] Referring to FIG. 2, in operation 221, a source device (source) and a first sink device (sink-1 (primary)) can perform at least one operation for connecting an ACL link. In operation 222, a source device (source) and a second sink device (sink-2 (secondary)) can perform at least one operation for connecting an ACL link. In operation 223, a source device (source) and a third sink device (sink-2 (secondary)) can perform at least one operation for connecting an ACL link. In operation 224, a source device (source) can broadcast data (or audio data) to a plurality of sink devices (sink-1, sink-2, sink-3) through a BIS connection.

[0046] <Case 3 - 절충 방식>

[0047] When the reception quality or reception delay time of data (or audio data) is set differently for each sink device, the source device (source) can establish a CIS connection or BIS connection with each of a plurality of sink devices (sink-1, sink-2, sink-3) and transmit and receive data through unicast communication or broadcast communication.

[0048] Referring to FIG. 2, in operation 231, a source device (source) and a first sink device (sink-1 (primary)) can perform at least one operation for connecting an ACL link. In operation 232, the source device (source) and the first sink device (sink-1 (primary)) can transmit and receive data and feedback on the data via a CIS connection. In operation 233, the source device (source) and a second sink device (sink-2 (secondary)) can perform at least one operation for connecting an ACL link. In operation 234, the source device (source) and a third sink device (sink-2 (secondary)) can perform at least one operation for connecting an ACL link. In operation 235, the source device (source) can broadcast data (or audio data) to a plurality of sink devices (sink-2, sink-3) via a BIS connection.

[0049] FIG. 3 illustrates an example of a plurality of electronic devices performing communication via a CIS method according to one embodiment of the present disclosure.

[0050] CIS stands for isochronous data logical transport, which allows connected electronic devices to transmit isochronous data unidirectionally and / or bidirectionally. Isochronous data can be transmitted on an LE-S or LE-F logical link using CIS logical transport, and each CIS can be connected to an LE asynchronous connection (LE ACL). Each CIS event can support variable-size packets and / or the transmission of one or more packets.

[0051] Each connected isochronous group (CIG) event can occur at regular isochronous intervals. For example, a CIG event can be implemented in a range of 5 ms to 4 s in multiples of 1.25 ms. A CIG event can include at least one CIS event. A CIS event can be a time resource allocated for unicast communication between a source device and a specific sink device.

[0052] Referring to FIG. 3, a first CIG event (CIG Event x) may include a first CIS event (CIS 0 Event y) and a second CIS event (CIS 1 Event y). The first CIS event (CIS 0 Event y) may be a time resource for transmitting and receiving audio data for a left channel (Left) (e.g., a left device among a pair of wireless earphones) of a source device and a sink device. The second CIS event (CIS 1 Event y) may be a time resource for transmitting and receiving audio data for a right channel (Right) (e.g., a right device among a pair of wireless earphones) of a source device and a sink device.

[0053] In each of the first CIS event (CIS 0 Event y) and the second CIS event (CIS 1 Event y), the source device can perform a BLE role as a central (C) and the sink device can perform a BLE role as a peripheral (P). In each of the first CIS event (CIS 0 Event y) and the second CIS event (CIS 1 Event y), in the "C->P" section, the source device can transmit audio data to the sink device, and in the "P->C" section, the sink device can transmit feedback (ACK / NACK) for the audio data to the source device.

[0054] In one embodiment, a maximum allowable delay time for the yth audio frame (or audio data) may be set. For example, if the content of the source device includes a video (e.g., YouTube, a game, etc.), issues may arise regarding audio / video sync (A / V sync) between the video played on the source device and the audio played on the sink devices, as well as simultaneous playback (synchronization) between the sink devices, and the sink device needs to receive the data until the maximum allowable delay time. For example, in the case of a game, since there is no time to play the delay through video buffering when considering the responsiveness felt by the user, scalability issues may arise as the number of audio sink devices increases.

[0055] After an isochronous interval from the start time of a first CIG event (CIG Event x), a second CIG event (CIG Event x+1) may occur. The second CIG event (CIG Event x+1) may include a third CIS event (CIS 0 Event y+1) and a second CIS event (CIS 1 Event y+1). The third CIS event (CIS 0 Event y+1) may be a time resource for transmitting and receiving audio data for a left channel (Left) of a source device and a sink device (e.g., a left device of a pair of wireless earphones). The second CIS event (CIS 1 Event y+1) may be a time resource for transmitting and receiving audio data for a right channel (Right) of a source device and a sink device (e.g., a right device of a pair of wireless earphones).

[0056] In one embodiment, a maximum delay allowance for the y+1th audio frame (or audio data) may be set.

[0057] FIG. 4 illustrates another example of a plurality of electronic devices communicating via a CIS method according to one embodiment of the present disclosure.

[0058] Referring to FIG. 4, a first CIG event (CIG Event x) may include a first CIS event (CIS 0 Event y), a second CIS event (CIS 1 Event y), and a third CIS event (CIS 2 Event y). The first CIS event (CIS 0 Event y) may be a time resource for transmitting and receiving audio data for a left channel (Left) (e.g., a left device of a pair of wireless earphones) of a source device and a first sink device. The second CIS event (CIS 1 Event y) may be a time resource for transmitting and receiving audio data for a right channel (Right) (e.g., a right device of a pair of wireless earphones) of a source device and a first sink device. The third CIS event (CIS 2 Event y) may be a time resource for transmitting and receiving audio data for a left channel (Left) (e.g., a left device of a pair of wireless earphones) of a source device and a second sink device.

[0059] According to one embodiment, a maximum delay allowable point in time for the yth audio frame (or audio data) may be set. In FIG. 4, before the maximum delay allowable point in time, time resources for the right channel (Right) of the source device and the second sink device (e.g., the left device of a pair of wireless earphones) may not be allocated. When communicating via the CIS method, as the number of sink devices increases, audio playback delay may occur due to limitations in the maximum delay allowable point in time and time resource allocation. For example, since it operates based on CIS (i.e., unicast transmission), when there are many audio sink devices, simultaneous playback may be performed based on the sink device that received audio data last, which may cause audio playback delay.

[0060] Referring to FIG. 4, even in the second CIG event (CIG Event x+1), time resources for the right channel (Right) of the source device and the second sink device (e.g., the left device of a pair of wireless earphones) may not be allocated before the maximum delay allowable time point of the y+1th audio frame.

[0061] FIG. 5 illustrates an example of a plurality of electronic devices performing communication via a BIS method according to one embodiment of the present disclosure.

[0062] In Fig. 5, when transmitting audio frames via the BIS method rather than the CIS method, data transmission can be possible before the playback time of each audio frame even if the number of sink devices increases (enhanced scalability). However, due to the nature of the BIS method not receiving feedback (ACK / NACK) on whether each sink device has received data, the PER (packet error rate) may be relatively higher than that of the CIS method. To address this, the source device may repeatedly transmit the same data (packet) multiple times.

[0063] In this disclosure, a method is proposed to improve packet reception rates by chase combining multiple packets at the bit level without discarding the packet even if an error is detected after receiving the packet by sink devices.

[0064] Broadcasting can be a method of streaming data (or audio frames) from at least one source device to multiple sink devices using a group of synchronized streams. Each stream used in broadcasting can be referred to as a broadcast isochronous stream (BIS), and a group of BISs can be referred to as a broadcast isochronous group (BIG).

[0065] A BIS logical transport can be used to transmit one or more isochronous data streams to all devices within the BIS (e.g., within a certain distance). A BIS can contain one or more subevents for transmitting isochronous data packets. A BIS can support the transmission of multiple isochronous data packets within each BIS event.

[0066] Referring to FIG. 5, a first BIG event (BIG Event x) may include a first BIS event (BIS 0 Event y) and a second BIS event (BIS 1 Event y). The first BIS event (BIS 0 Event y) may be a time resource for a source device to broadcast audio data (or audio frame) for a left channel (Left) of at least one sink device (e.g., a left device of a pair of wireless earphones). The second BIS event (BIS 1 Event y) may be a time resource for a source device to broadcast audio data (or audio frame) for a right channel (Right) of at least one sink device (e.g., a right device of a pair of wireless earphones).

[0067] In a first BIS event (BIS 0 Event y), the source device can transmit the yth audio frame for the left channel (Left) of at least one sink device three times. In a second BIS event (BIS 1 Event y), the source device can transmit the yth audio frame for the right channel (Right) of at least one sink device three times.

[0068] According to one embodiment, in each of the first BIS event (BIS 0 Event y) and the second BIS event (BIS 1 Event y), at least one source device may recover the error by chasing combining a plurality of y-th audio frames (e.g., three) at the bit level, without discarding the audio frame even if an error is detected after receiving the y-th audio frame.

[0069] In one embodiment, a maximum delay allowance point for the yth audio frame (or audio data) may be set. In FIG. 5, the audio frame is transmitted using the BIS method, so that multiple sink devices can receive the yth audio frame before the maximum delay allowance point.

[0070] A second BIG event (BIG Event x+1) may occur after an ISO interval from the start time of a first BIG event (BIG Event x). The second BIG event (BIG Event x+1) may include a third BIS event (BIS 0 Event y+1) and a fourth BIS event (BIS 1 Event y+1). The third BIS event (BIS 0 Event y+1) may be a time resource for a source device to broadcast audio data (or an audio frame) for a left channel (Left) of at least one sink device (e.g., a left device of a pair of wireless earphones). The fourth BIS event (BIS 1 Event y+1) may be a time resource for a source device to broadcast audio data (or an audio frame) for a right channel (Right) of at least one sink device (e.g., a right device of a pair of wireless earphones).

[0071] In the third BIS event (BIS 0 Event y+1), the source device can transmit the y+1th audio frame for the left channel (Left) of at least one sink device three times. In the fourth BIS event (BIS 1 Event y+1), the source device can transmit the y+1th audio frame for the right channel (Right) of at least one sink device three times.

[0072] According to one embodiment, in each of the third BIS event (BIS 0 Event y+1) and the fourth BIS event (BIS 1 Event y+1), at least one source device may not discard the y+1th audio frame even if an error is detected after receiving the y+1th audio frame, but may recover the error by chase combining a plurality of y+1th audio frames (e.g., three) at the bit level.

[0073] In one embodiment, a maximum delay allowance point for the y+1th audio frame (or audio data) may be set. In FIG. 5, the audio frame is transmitted via the BIS method, so that multiple sink devices can receive the y+1th audio frame before the maximum delay allowance point.

[0074] FIG. 6 is a diagram for explaining a packet receiving operation of a BIS sink device according to one embodiment of the present disclosure.

[0075] The BIS sink device can recover errors in data where errors are detected at the bit level by comparing bits in the same position (position bits) and applying the maximum likelihood method.

[0076] Referring to FIG. 6, in operation 601, a BIS event may be initiated between a BIS source device and a BIS sink device. In operation 603, the BIS sink device may receive a packet broadcast from the BIS source device in an i-th BIS subevent. The BIS event may include multiple subevents, each of which broadcasts audio data.

[0077] In operation 605, the BIS sink device may perform demodulation and a cyclic redundancy check (CRC) on the packet received in the i-th BIS subevent. In operation 607, the BIS sink device may determine whether an error is detected for the packet based on the CRC result.

[0078] If no error is detected in the packet based on the CRC result (607-No), then in action 609, the BIS sink device may terminate the receive operation on the BIS event.

[0079] If an error is detected in the packet based on the CRC result (607-Yes), in operation 611, the BIS sink device may store the bit level of the packet in which the error is detected and perform bit level chase combining. In one embodiment, the bit level chase combining may be a method of comparing each of a plurality of transmission data bit by bit to detect an error in a specific bit in a specific transmission data (for example, detecting an error in the 5th bit in the second received transmission data), and removing the detected error.

[0080] In operation 613, the BIS sink device can check whether an error is detected in the packet after performing bit level chase combining.

[0081] If no error is detected in the packet (613-No), then in action 609, the BIS sink device may terminate the receiving operation for the BIS event. If an error is detected in the packet (613-Yes), then in action 615, the BIS sink device may determine whether the sub-event is the last sub-event within the BIS event.

[0082] If the sub-event is the last sub-event within a BIS event (615-Yes), then in action 609, the BIS sink device may terminate the receiving operation on the BIS event.

[0083] If the subevent is not the last subevent within the BIS event (615-No), then in operation 617, the BIS sink device increments i by 1, and in operation 603, the BIS sink device can receive a packet broadcast from the BIS source device in the i-th BIS subevent.

[0084] FIG. 7 is a diagram for explaining a bit-level error recovery method of a BIS sink device according to one embodiment of the present disclosure.

[0085] In Fig. 7, for example, BER (bit error rate): 10 -3 , packet length = 512 bytes, number of identical packet transmissions: This shows the bit-level error recovery method of the BIS sink device when set to 3. At this time, BER represents the number of bits that have errors in the transmission process for the number of received bits. The example shown in Fig. 7 is only an example for the convenience of explanation, and situations (e.g., BER, packet length, number of identical packet transmissions) during BIS data transmission can be implemented in various ways.

[0086] Referring to FIG. 7, the transmission data may include bits of "01101010001010101010101010...1010101010010101010100010101". At this time, the first reception data received by the BIS sink device for the first time may include bits of "0110101000001010101110...101010100101111100010101", the second reception data received by the BIS sink device for the second time may include bits of "011000100110101010101010101010...10100010100101010100100101", and the third reception data received by the BIS sink device for the third time may include bits of "00101010001010111010101010...10101010100101010100010111".

[0087] The BIS sink device can compare the first, second, and third received data bit by bit to detect whether an error has occurred in a plurality of bits of each received data. If an error is detected in some bits of each received data, the BIS sink device can reflect the error and correct the error in the received data.

[0088] For example, the BIS sink device can compare the bits in the second positions of the first, second, and third received data, respectively, and detect that only the bit in the second position of the third received data is "0", and thus the corresponding bit is an error. Thereafter, the BIS sink device can determine the bit in the second position of the received data to be "1" to eliminate the error.

[0089] For example, the BIS sink device can compare the bits at the 5th position of each of the first received data, the second received data, and the third received data, and detect that only the bit at the 5th position of the second received data is "0", and thus the corresponding bit is an error. Thereafter, the BIS sink device can determine the bit at the 5th position of the received data to be "1" to eliminate the error.

[0090] The present disclosure can implement various transmission Modulation and Coding Schemes (MCS) by performing bit-level chase combining rather than symbol-level. For example, a BIS source device can broadcast first data based on 16QAM, second data based on 8PSK, and third data based on QPSK. According to one embodiment, the BIS source device can increase the number of BIS sub-events by using a high MCS, unlike existing broadcasts that use a robust MCS.

[0091] The probability of successful packet reception can be increased when applying the bit level chase combining proposed in this disclosure.

[0092] P is the probability of successful reception of the i-th packet s,i can be calculated based on mathematical formula 1.

[0093] [Mathematical Formula 1]

[0094]

[0095] In this disclosure, is the BER of the i-th transmitted packet (dependent on the transmission MCS), and L may be the packet length.

[0096] If the number of repeated transmissions of the same packet is n, the probability of successful packet reception when repeated transmissions are n is can be calculated based on mathematical formula 2.

[0097] [Equation 2]

[0098]

[0099] After applying bit level chase combining using packets received n times, BER is If the BER is the same for all repeated transmissions (i.e., ) can be calculated based on mathematical formula 3.

[0100] [Equation 3]

[0101] (At this time, if n is an even number, conservatively assume an error when 1 and 0 are the same number)

[0102] When applying bit level chase combining using packets received n times repeatedly, the probability of successful reception is can be calculated based on mathematical formula 4.

[0103] [Equation 4]

[0104]

[0105] That is, when bit level chase combining is applied, the probability of successful packet reception is It can increase by that much.

[0106] According to one embodiment, a BIS source device can determine the number of repeat transmissions for the same packet based on a target packet reception success probability for at least one BIS sink device.

[0107] FIG. 8 is a diagram for explaining the effect of a bit-level error recovery method according to one embodiment of the present disclosure.

[0108] Referring to Figure 8, the probability of successful reception of the i-th packet is , the probability of successful packet reception when transmitting n times , and the probability of successful reception when bit level chase combining is applied using packets received n times repeatedly. The relationship between packet success rate and BER for each is shown.

[0109] Figure 8 is proposed in the present disclosure. To illustrate the effective aspect, when n=3, BER for each transmission is the same, and L=4096 bits, and Even in the low BER range, the packet success probability can be maintained above a certain level.

[0110] In one embodiment, if the BER per transmission is not the same, a higher transmission rate (i.e., a higher MCS) can be utilized to reduce transmission time. For example, 16 QAM can be utilized compared to QPSK to double the number of transmissions in the same amount of time.

[0111] For example, according to the settings of each parameter as shown in Table 1 below, and can be implemented in various ways.

[0112] [Table 1]

[0113]

[0114] FIG. 9 is a diagram for explaining the effect of a bit-level error recovery method according to one embodiment of the present disclosure.

[0115] Referring to Figure 9, the probability of successful reception of the i-th packet is , the probability of successful packet reception when transmitting n times , and the probability of successful reception when bit level chase combining is applied using packets received n times repeatedly. The relationship between packet success rate and BER for each is shown.

[0116] Figure 9 is proposed in the present disclosure. To illustrate the effective aspect, when n=5, BER for each transmission is the same, and L=4096 bits, and Even in the low BER range, the packet success probability can be maintained above a certain level.

[0117] FIG. 10 illustrates an example of a plurality of electronic devices performing communication via the BIS method and the ACL method according to one embodiment of the present disclosure.

[0118] In Fig. 10, a method is proposed to further increase the probability of successful packet reception by having the BIS sink device transmit separate feedback to the BIS source device even though it is a broadcast transmission method.

[0119] Referring to FIG. 10, a first BIG event (BIG Event x) may include a first BIS event (BIS 0 Event y) and a second BIS event (BIS 1 Event y). The first BIS event (BIS 0 Event y) may be a time resource for a source device to broadcast audio data (or audio frame) for a left channel (Left) of at least one sink device (e.g., a left device of a pair of wireless earphones). The second BIS event (BIS 1 Event y) may be a time resource for a source device to broadcast audio data (or audio frame) for a right channel (Right) of at least one sink device (e.g., a right device of a pair of wireless earphones).

[0120] In a first BIS event (BIS 0 Event y), the source device can transmit the yth audio frame for the left channel (Left) of at least one sink device three times. In a second BIS event (BIS 1 Event y), the source device can transmit the yth audio frame for the right channel (Right) of at least one sink device three times.

[0121] According to one embodiment, in the fourth sub-event within the second BIS event (BIS 1 Event y), at least one sink device may transmit a message or information requesting retransmission of the y-th audio frame (or audio data) to the source device. According to one embodiment, if the number of subevents (NSE) within a specific BIS event is greater than the number of data retransmission repetitions (repeat number), the sink device may transmit a message or information requesting retransmission of the audio frame (or audio data) to the source device in the immediately next sub-event after the retransmission repetitions. The NSE denotes the number of sub-events per BIS in each BIG event.

[0122] In one embodiment, when a source device receives a message or information requesting retransmission of an audio frame (or audio data) from at least one sink device, the source device may request individual feedback via an ACL to each sink device to determine which sink device requested the retransmission. In one embodiment, the source device may unicast the data via an ACL to the sink device requesting the data retransmission.

[0123] For example, a source device may transmit a Poll message on an ACL channel (ACL for sink-1) for a first sink device and receive an ACK message from the first sink device indicating that it successfully received data in the corresponding BIS event.

[0124] For example, a source device may transmit a Poll message on an ACL channel for a second sink device (ACL for sink-2) and receive a NACK message from the second sink device indicating that it did not successfully receive data for the corresponding BIS event. The source device receiving the NACK message may retransmit the data to the second sink device on the ACL channel for the second sink device (ACL for sink-2). Upon successfully receiving the data, the second sink device may transmit an ACK message to the source device on the ACL channel for the second sink device (ACL for sink-2).

[0125] For example, a source device may transmit a Poll message on an ACL channel (ACL for sink-3) for a third sink device and receive an ACK message from the third sink device indicating that it successfully received data in the corresponding BIS event.

[0126] In one embodiment, a maximum delay allowance point for the yth audio frame (or audio data) may be set. In FIG. 10, the audio frame is transmitted using the BIS method, so that multiple sink devices can receive the yth audio frame before the maximum delay allowance point.

[0127] A second BIG event (BIG Event x+1) may occur after an ISO interval from the start time of a first BIG event (BIG Event x). The second BIG event (BIG Event x+1) may include a third BIS event (BIS 0 Event y+1) and a fourth BIS event (BIS 1 Event y+1). The third BIS event (BIS 0 Event y+1) may be a time resource for a source device to broadcast audio data (or an audio frame) for a left channel (Left) of at least one sink device (e.g., a left device of a pair of wireless earphones). The fourth BIS event (BIS 1 Event y+1) may be a time resource for a source device to broadcast audio data (or an audio frame) for a right channel (Right) of at least one sink device (e.g., a right device of a pair of wireless earphones).

[0128] In the third BIS event (BIS 0 Event y+1), the source device can transmit the y+1th audio frame for the left channel (Left) of at least one sink device three times. In the fourth BIS event (BIS 1 Event y+1), the source device can transmit the y+1th audio frame for the right channel (Right) of at least one sink device three times.

[0129] According to one embodiment, in the fourth sub-event within the third BIS event (BIS 0 Event y+1), at least one sink device may transmit a message or information requesting retransmission for the y+1th audio frame (or audio data) to the source device.

[0130] For example, a source device may transmit a Poll message on an ACL channel (ACL for sink-1) for a first sink device and receive an ACK message from the first sink device indicating that it successfully received data in the corresponding BIS event.

[0131] For example, a source device may transmit a Poll message on an ACL channel for a second sink device (ACL for sink-2) and receive a NACK message from the second sink device indicating that it did not successfully receive data for the corresponding BIS event. The source device receiving the NACK message may retransmit the data to the second sink device on the ACL channel for the second sink device (ACL for sink-2). Upon successfully receiving the data, the second sink device may transmit an ACK message to the source device on the ACL channel for the second sink device (ACL for sink-2).

[0132] For example, a source device may transmit a Poll message on an ACL channel for a third sink device (ACL for sink-3) and receive a NACK message from the third sink device indicating that it did not successfully receive data for the corresponding BIS event. The source device receiving the NACK message may retransmit the data to the third sink device on the ACL channel for the third sink device (ACL for sink-3). If the data is not successfully received, the third sink device may retransmit a NACK message to the source device on the ACL channel for the third sink device (ACL for sink-3). The source device receiving the NACK message may retransmit the data to the third sink device on the ACL channel for the third sink device (ACL for sink-3). If the data is successfully received, the third sink device may transmit an ACK message to the source device on the ACL channel for the third sink device (ACL for sink-3).

[0133] In one embodiment, a maximum delay allowance point for the y+1th audio frame (or audio data) may be set. In FIG. 10, the audio frame is transmitted using the BIS method, so that multiple sink devices can receive the y+1th audio frame before the maximum delay allowance point.

[0134] FIG. 11 illustrates a configuration of a source device according to one embodiment of the present disclosure.

[0135] The source device of FIG. 11 can be implemented as any one of the source devices, BIS source devices, and CIS source devices illustrated in FIGS. 1 to 10.

[0136] Referring to FIG. 11, the source device may include a processor (1101), a transceiver (1103), and a memory (1105). In the present disclosure, the processor (1101) may be defined as a circuit or an application-specific integrated circuit or at least one processor. The processor (1101) may also be referred to as a control unit or controller.

[0137] The processor (1101) can control the overall operation of the source device described in the embodiments proposed in the present disclosure. Specifically, the processor (1101) can control the operation of any one of the source devices, BIS source devices, and CIS source devices illustrated in FIGS. 1 to 10, for example.

[0138] The transceiver (1103) can transmit and receive signals with other electronic devices or at least one sink device. The transceiver (1103) may also be referred to as a transceiver or a transceiver.

[0139] The memory (1105) can store at least one of information transmitted and received through the transceiver (1103) and information generated through the processor (1101).

[0140] FIG. 12 illustrates a configuration of a sink device according to one embodiment of the present disclosure.

[0141] The sink device of FIG. 12 can be implemented as any one of the sink devices, BIS sink devices, and CIS sink devices illustrated in FIGS. 1 to 10.

[0142] Referring to FIG. 12, the sink device may include a processor (1201), a transceiver (1203), and a memory (1205). In the present disclosure, the processor (1201) may be defined as a circuit or application-specific integrated circuit or at least one processor. The processor (1201) may also be referred to as a control unit or controller.

[0143] The processor (1201) can control the overall operation of the sink device described in the embodiments proposed in the present disclosure. Specifically, the processor (1201) can control the operation of any one of the sink devices, BIS sink devices, and CIS sink devices illustrated in FIGS. 1 to 10, for example.

[0144] The transceiver (1203) can transmit and receive signals with other electronic devices or source devices. The transceiver (1203) may also be referred to as a transceiver or a transceiver.

[0145] The memory (1205) can store at least one of information transmitted and received through the transceiver (1203) and information generated through the processor (1201).

[0146] According to one embodiment, the processor (1201) may receive control information for a broadcast isochronous stream (BIS) connection with a source electronic device from the source electronic device. According to one embodiment, the processor (1201) may receive a packet from the source electronic device in a first sub-event within a BIS (broadcast isochronous stream) event set based on the control information. According to one embodiment, the processor (1201) may receive the packet from the source electronic device in a second sub-event within the BIS event. According to one embodiment, the processor (1201) may receive the packet from the source electronic device in a third sub-event within the BIS event. According to one embodiment, the processor (1201) may compare each of the packets received in the first sub-event, the packets received in the second sub-event, and the packets received in the third sub-event at a bit level to detect a bit error and perform combining to recover the bit error.

[0147] According to one embodiment, the processor (1201) may perform demodulation and a cyclic redundancy check (CRC) on the packet received in the first sub-event. According to one embodiment, the processor (1201) may perform demodulation and a cyclic redundancy check (CRC) on the packet received in the second sub-event. According to one embodiment, the processor (1201) may perform demodulation and a CRC on the packet received in the second sub-event.

[0148] According to one embodiment, the processor (1201) may determine whether an error is detected in at least one packet among the packet received in the first sub-event, the packet received in the second sub-event, and the packet received in the third sub-event. According to one embodiment, the processor (1201) may store a bit level of at least one packet in which an error is detected, and perform bit level combining on the at least one packet to recover the error.

[0149] In one embodiment, within the BIS event, the second sub-event may be positioned immediately following the first sub-event on the time axis, and within the BIS event, the third sub-event may be positioned immediately following the second sub-event on the time axis.

[0150] According to one embodiment, the processor (1201) may establish a connection to the source electronic device and an asynchronous connection-oriented logical transport (ACL) link.

[0151] According to one embodiment, the processor (1201) may transmit a message requesting retransmission of the packet to the source electronic device in a fourth sub-event located immediately after the third sub-event on the time axis within the BIS event.

[0152] In one embodiment, the processor (1201) may receive a poll message from the source electronic device over the ACL link. In one embodiment, the processor (1201) may, in response to the poll message, transmit a NACK message to the source electronic device over the ACL link, indicating that the packet broadcast from the source electronic device was not successfully received. In one embodiment, the processor (1201) may receive the packet from the source electronic device over the ACL link.

[0153] In the specific embodiments of the present disclosure described above, components included in the present disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0154] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In a method of operating a sink electronic device in a wireless communication system, An operation of receiving control information for a BIS (broadcast isochronous stream) connection with a source electronic device from the source electronic device; An operation of receiving a packet from the source electronic device in a first sub-event within a BIS (broadcast isochronous stream) event established based on the above control information; In a second sub-event within the above BIS event, an action of receiving the packet from the source electronic device; In a third sub-event within the above BIS event, an action of receiving the packet from the source electronic device; and A method characterized by including an operation of comparing each of the packets received in the first sub-event, the packets received in the second sub-event, and the packets received in the third sub-event at a bit level to detect a bit error, and performing combining to recover the bit error.

2. In paragraph 1, An operation of performing demodulation and CRC (cyclic redundancy check) on the packet received in the first sub-event; An operation of performing demodulation and CRC on the packet received in the second sub-event; and A method characterized by further comprising an operation of performing demodulation and CRC on the packet received in the second sub-event.

3. In paragraph 2, An operation of determining whether an error is detected in at least one of the packets received in the first sub-event, the packets received in the second sub-event, and the packets received in the third sub-event; An operation of storing the bit level of at least one packet in which the above error is detected; and A method characterized by further comprising the action of performing bit-level combining on said at least one packet to recover said error.

4. In paragraph 1, Within the above BIS event, the second sub-event is located immediately following the first sub-event on the time axis, A method characterized in that, within the above BIS event, the third sub-event is located immediately following the second sub-event on the time axis.

5. In paragraph 1, A method further comprising establishing a connection to the source electronic device and an asynchronous connection-oriented logical transport (ACL) link.

6. In paragraph 5, A method characterized by further comprising the action of transmitting, to the source electronic device, a message requesting retransmission of the packet in a fourth sub-event located immediately following the third sub-event on the time axis within the BIS event.

7. In paragraph 6, An action of receiving a poll message from the source electronic device on the ACL link; In response to said poll message, transmitting a NACK message to said source electronic device over said ACL link, indicating that said packet broadcast from said source electronic device was not successfully received; and A method further characterized by comprising the action of receiving the packet from the source electronic device over the ACL link.

8. In a sink electronic device in a wireless communication system, Transmitter and receiver; and comprising a processor, said processor comprising: Receiving control information for a BIS (broadcast isochronous stream) connection with a source electronic device from the source electronic device, In a first sub-event within a BIS (broadcast isochronous stream) event set based on the above control information, a packet is received from the source electronic device, In the second sub-event within the above BIS event, the packet is received from the source electronic device, In the third sub-event within the above BIS event, the packet is received from the source electronic device, A device characterized in that it compares each of the packets received in the first sub-event, the packets received in the second sub-event, and the packets received in the third sub-event at a bit level to detect a bit error, and performs combining to recover the bit error.

9. In the 8th paragraph, the processor, Perform demodulation and CRC (cyclic redundancy check) on the packet received in the first sub-event, Perform demodulation and CRC on the packet received in the second sub-event, A device characterized by performing demodulation and CRC on the packet received in the second sub-event.

10. In the 9th paragraph, the processor, Check whether an error is detected in at least one of the packets received in the first sub-event, the packets received in the second sub-event, and the packets received in the third sub-event; Store the bit level of at least one packet in which the above error is detected, A device characterized by performing bit-level combining on at least one packet to recover from the above error.

11. In paragraph 8, Within the above BIS event, the second sub-event is located immediately following the first sub-event on the time axis, A device characterized in that within the above BIS event, the third sub-event is located immediately following the second sub-event on the time axis.

12. In the 8th paragraph, the processor, A device characterized by establishing a connection to the source electronic device and an asynchronous connection-oriented logical transport (ACL) link.

13. In paragraph 12, the processor, A device characterized in that, in a fourth sub-event located immediately following the third sub-event on the time axis within the BIS event, a message requesting retransmission of the packet is transmitted to the source electronic device.

14. In the 13th paragraph, the processor, Receive a poll message from the source electronic device on the above ACL link, In response to the above poll message, transmit a NACK message to the source electronic device over the ACL link, indicating that the packet broadcast from the source electronic device was not successfully received; A device characterized by receiving the packet from the source electronic device over the ACL link.

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