Method and apparatus for transmitting or receiving broadcast stream

Abstract

The present disclosure relates to a method and apparatus for transmitting or receiving a broadcast stream in a wireless communication system, the method comprising the steps of: identifying a first time interval related to a first broadcast stream and a second time interval related to a second broadcast stream, on the basis of information about a broadcast stream group comprising the first broadcast stream and the second broadcast stream; if first data related to the first broadcast stream is not successfully received in the first time interval related to the first broadcast stream, transmitting a first negative acknowledgement (NACK) signal in the second time interval related to the second broadcast stream; and in response to the first NACK signal, receiving the first data related to the first broadcast stream in the second time interval related to the second broadcast stream. According to the present disclosure, it is possible to expect technical effects that may improve the packet delivery ratio (PDR) and reception quality for broadcast-based transmission and extend coverage.

Description

Method and device for transmitting or receiving a broadcast stream

[0001] The present disclosure relates to a wireless communication system, and more specifically, to a method for transmitting or receiving a broadcast stream and an apparatus for doing so.

[0002] Bluetooth® technology has supported Bluetooth LE (Low Energy) since the core specification v4.0, and Bluetooth LE is used in various electronic devices such as smartphones and wireless earphones by reducing power consumption compared to other wireless communication technologies.

[0003] In addition, since Bluetooth® LE (BLE) Core specification v5.2, support has been provided for broadcast isochronous groups (BIGs) containing multiple broadcast isochronous streams (BISs), and various applications utilizing BIGs and BISs are being developed. For example, Auracast, an audio broadcast application utilizing BLE technology, is an example. TM This was developed.

[0004] However, since ACK (acknowledgement) is not used in broadcast streams such as BIG and BIS, there are technical issues where the reception rate cannot be guaranteed, the PDR (packet delivery ratio) may be low, and the quality of the user experience may be poor. In addition, there are aspects where the coverage of BLE-supporting devices is limited, so a method to expand the coverage of BLE-supporting devices is required.

[0005] The technical problem of the present disclosure is to provide a method and an apparatus capable of improving the packet delivery ratio (PDR) and reception quality of broadcast-based transmission.

[0006] The technical problem of the present disclosure is to provide a method and an apparatus for improving PDR and reception quality for broadcast-based transmission without changing or affecting the transmitter operation for broadcast-based transmission.

[0007] The technical problem of the present disclosure is to provide a method and apparatus for improving the PDR and reception quality for a broadcast-based transmission while maintaining or decreasing the number of unconditional retransmissions by the transmitter for a broadcast-based transmission without increasing it.

[0008] The technical problem of the present disclosure is to provide a method and an apparatus that can improve the coverage of a transmitter for broadcast-based transmission.

[0009] The technical problems to be solved in the various embodiments of the present disclosure are not limited to those mentioned above, and other technical problems not mentioned may be considered by those skilled in the art from the various embodiments of the present disclosure described below.

[0010] As a first aspect of the present disclosure, a method performed by an electronic device in a wireless communication system is provided, the method may include: identifying a first time interval associated with the first broadcast stream and a second time interval associated with the second broadcast stream based on information regarding a group of broadcast streams including a first broadcast stream and a second broadcast stream; transmitting a first NACK (negative acknowledgment) signal in a second time interval associated with the second broadcast stream if the first data associated with the first broadcast stream is not successfully received in the first time interval associated with the first broadcast stream; and receiving the first data associated with the first broadcast stream in a second time interval associated with the second broadcast stream in response to the first NACK signal.

[0011] As a second aspect of the present disclosure, an electronic device configured to operate in a wireless communication system is provided, wherein the electronic device comprises: a transceiver; at least one processor connected to the transceiver; and a memory comprising instructions configured to implement an operation when performed by the at least one processor, wherein the operation may include: identifying a first time interval associated with the first broadcast stream and a second time interval associated with the second broadcast stream based on information regarding a group of broadcast streams including a first broadcast stream and a second broadcast stream; transmitting a first NACK (negative acknowledgment) signal in a second time interval associated with the second broadcast stream if the first data associated with the first broadcast stream is not successfully received in the first time interval associated with the first broadcast stream; and receiving the first data associated with the first broadcast stream in a second time interval associated with the second broadcast stream in response to the first NACK signal.

[0012] As a third aspect of the present disclosure, a non-transient computer-readable recording medium is provided that includes an instruction configured to enable an electronic device comprising at least one processor to implement an operation when performed by at least one processor, wherein the operation may include: identifying a first time interval associated with the first broadcast stream and a second time interval associated with the second broadcast stream based on information regarding a group of broadcast streams comprising a first broadcast stream and a second broadcast stream; transmitting a first NACK (negative acknowledgment) signal in a second time interval associated with the second broadcast stream if the first data associated with the first broadcast stream is not successfully received in the first time interval associated with the first broadcast stream; and receiving the first data associated with the first broadcast stream in a second time interval associated with the second broadcast stream in response to the first NACK signal.

[0013] In one embodiment of the present disclosure, the method or the operation may further include: a step of detecting a second NACK signal in a second time interval associated with a second broadcast stream when the first data associated with the first broadcast stream is successfully received in a first time interval associated with the first broadcast stream; and a step of transmitting the first data associated with the first broadcast stream in a second time interval associated with the second broadcast stream when the second NACK signal is detected in a second time interval associated with the second broadcast stream.

[0014] In one embodiment of the present disclosure, the step of transmitting first data associated with the first broadcast stream in a second time interval associated with the second broadcast stream may include transmitting first data associated with the first broadcast stream through random backoff-based competition in the second time interval.

[0015] In one embodiment of the present disclosure, when the second NACK signal is detected in the second time interval associated with the second broadcast stream, the first data associated with the first broadcast stream may not be transmitted through random backoff-based competition in the second time interval associated with the second broadcast stream.

[0016] In one embodiment of the present disclosure, if the first data associated with the first broadcast stream is successfully received in a first time interval associated with the first broadcast stream, the method may further include the step of transmitting the first data associated with the first broadcast stream after a maximum random backoff time in a second time interval associated with the second broadcast stream.

[0017] In one embodiment of the present disclosure, the first channel for the first data associated with the first broadcast stream in the second time interval associated with the second broadcast stream and the second channel for the first data associated with the second broadcast stream in the second time interval associated with the second broadcast stream may be different from each other.

[0018] In one embodiment of the present disclosure, the index of the first channel may be determined based on the value obtained by adding the channel index for the first data associated with the first broadcast stream and the hop increase value in a first time interval associated with the first broadcast stream.

[0019] In one embodiment of the present disclosure, the first NACK signal may be transmitted in a second time interval associated with the second broadcast stream through a channel used for receiving the first data associated with the first broadcast stream in a first time interval associated with the first broadcast stream.

[0020] In one embodiment of the present disclosure, the first NACK signal may be transmitted based on an energy detection method.

[0021] In one embodiment of the present disclosure, when the event for the broadcast stream group does not include a control sub-event, the time interval from the start time of the event for the broadcast stream group to the start time of the next event for the broadcast stream group is set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing, where Num_BIS represents the number of broadcast streams in the broadcast stream group, BIS_Spacing represents the time interval between the start time of the sub-event of the first broadcast stream in the broadcast stream group and the start time of the sub-event of the second broadcast stream corresponding to the sub-event of the first broadcast stream, Sub_Interval represents the time interval between the start times of two consecutive sub-events of one broadcast stream, and max(A,B) may represent the larger value between A and B.

[0022] In one embodiment of the present disclosure, when an event for the broadcast stream group includes a control sub-event, the time offset from the start time of the event for the broadcast stream group to the start time of the control sub-event is set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing, where Num_BIS represents the number of broadcast streams in the broadcast stream group, BIS_Spacing represents the time interval between the start time of the sub-event of the first broadcast stream in the broadcast stream group and the start time of the sub-event of the second broadcast stream corresponding to the sub-event of the first broadcast stream, Sub_Interval represents the time interval between the start times of two consecutive sub-events of one broadcast stream, and max(A,B) may represent the larger value between A and B.

[0023] In one embodiment of the present disclosure, the first broadcast stream and the second broadcast stream may be received based on at least one of a sequential method or an interleaved method.

[0024] In one embodiment of the present disclosure, each of the first broadcast stream and the second broadcast stream includes a broadcast isochronous stream (BIS), the broadcast stream group includes a broadcast isochronous group (BIG), information regarding the broadcast stream group includes BIG information, and each of the first time interval and the second time interval may include a BIS sub-event.

[0025] According to the present disclosure, the packet delivery ratio (PDR) and reception quality of broadcast-based transmission can be improved.

[0026] According to the present disclosure, the PDR and reception quality for a broadcast-based transmission can be improved without changing the transmitter operation for the broadcast-based transmission or without affecting the transmitter operation.

[0027] According to the present disclosure, the PDR and reception quality for broadcast-based transmission can be improved while reducing, rather than increasing, the number of unconditional retransmissions by the transmitter for broadcast-based transmission.

[0028] According to the present disclosure, the coverage of a transmitter for broadcast-based transmission can be improved.

[0029] The effects obtainable in the present disclosure are not limited to those mentioned in the various embodiments, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure pertains from the description below.

[0030] Figures 1a and 1b are Auracast TM Examples of broadcasting audio streams based on [this] are provided.

[0031] FIG. 2 illustrates a channel that can be used in the present disclosure.

[0032] FIG. 3 illustrates channel hopping that can be used in the present disclosure.

[0033] Figure 4 illustrates the procedure for establishing a BIS.

[0034] FIG. 5 illustrates a format of BIG information that can be used in the present disclosure.

[0035] Figure 6 illustrates a BIG event, a BIS event, and a BIS sub-event.

[0036] Figures 7a and 7b illustrate an example where BIG includes multiple BIS.

[0037] FIG. 8 illustrates a packet structure that can be used in the present disclosure.

[0038] FIG. 9 illustrates an example of a system to which the present disclosure may be applied.

[0039] FIGS. 10a and FIGS. 10b illustrate an example in which the proposed method of the present disclosure is applied to a group of broadcast streams arranged sequentially according to one embodiment of the present disclosure.

[0040] FIGS. 11a and FIGS. 11b illustrate an example in which the proposed method of the present disclosure is applied to a group of broadcast streams arranged in an interleaved manner according to one embodiment of the present disclosure.

[0041] FIGS. 12a to 12c illustrate an example in which the proposed method of the present disclosure is applied to a broadcast stream group according to one embodiment of the present disclosure.

[0042] FIG. 13 illustrates a flowchart of the proposed method of the present disclosure.

[0043] FIG. 14 illustrates the structure of a device in which the proposed method of the present disclosure can be implemented.

[0044] The present disclosure will be described in detail below with reference to the attached drawings.

[0045] In the detailed description of the present disclosure, specific descriptions of related prior art are omitted if it is determined that such descriptions would unnecessarily obscure the gist of the matter. Additionally, numbers used in the detailed description (e.g., first, second, etc.) are merely identification symbols to distinguish one component from another.

[0046] The terms used in this disclosure have been selected to be as widely used and general as possible, taking into account their functions within this disclosure; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms have been selected at the applicant's discretion, and in such cases, their meanings will be described in detail in the relevant explanatory sections. Therefore, terms used in this disclosure should be defined not merely by their names, but based on their meanings and the overall content of this disclosure.

[0047] Singular expressions may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art as described in this specification. Additionally, terms including ordinal numbers, such as "first" or "second," used in this specification may be used to describe various components, but said components should not be limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another.

[0048] When a part of the specification is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as "unit (or part)," "module," etc., as used in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or as a combination of hardware and software.

[0049] Embodiments of the present disclosure are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present disclosure in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals. Additionally, the reference numerals used in each drawing are for the purpose of describing each drawing only, and different reference numerals used in different drawings are not intended to represent different elements.

[0050] Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected" or "physically connected," but also cases where they are "electrically connected" with other elements in between. In this disclosure, the terms "transmit," "receive," and "communicate" include both direct and indirect communication. Furthermore, when a part is described as "include" or "comprise" a component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0051] Throughout this disclosure, unless specifically stated otherwise, "or" is inclusive and not exclusive. Accordingly, unless clearly otherwise indicated or otherwise indicated in the context, "A or B" may mean "A, B, or both." In this disclosure, the phrases "at least one of" or "one or more of" may mean that different combinations of one or more of the listed items may be used, or that only any one of the listed items is required. For example, "at least one of A, B, and / or C" may include any of the following combinations: A, B, C, A and B, A and C, B and C, or A and B and C. In this disclosure, the expression "at least one of A, B, or C" may refer to "A," "B," "C," "A and B," "A and C," "B and C," "A, B, and C all," or variations thereof.

[0052] In one embodiment of the present disclosure, "connection relationship" may include the meanings of "connection relationship," "inclusion relationship," "attachment relationship," or "matching relationship." For example, "connected" may include the meanings of "connected," "included," "attached," or "matched." In one embodiment of the present disclosure, "connection" may include the meaning that data communication is possible via wired or wireless means. For example, "A and B are connected" may include the meaning that A and B are capable of data communication, that is, capable of transmitting and receiving data to and from each other.

[0053] Although this disclosure is described based on the Bluetooth® Low Energy (BLE) standard, this disclosure is not limited to the BLE standard and may be equally or similarly applied to other similar communication technologies. In this disclosure, the device may be a device that supports the BLE standard, but the device in this disclosure may also be a device that supports a communication technology other than the BLE standard. In this disclosure, BLE may be collectively referred to as Bluetooth®.

[0054] In this disclosure, a broadcast stream may refer to a data stream that is broadcast from one device to an unspecified number of devices. To aid in understanding this disclosure, the description assumes a situation where a BIS according to the BLE standard is used; however, this disclosure may be applied identically or similarly even when a different form of broadcast stream is used instead of the BLE standard's BIS. For example, a broadcast stream may include a broadcast isochronous stream (BIS) according to the BLE standard, but it may also include a data stream broadcast according to a communication technology other than BLE. In this disclosure, a broadcast stream may include various types of data such as audio streams, video streams, digital content, application data, files, etc. Data constituting a broadcast stream may be transmitted and received in the form of packets, and a packet containing data may be briefly referred to as data. For example, in this disclosure, data may be transmitted through a packet exemplified in FIG. 8, but in this disclosure, data may also be transmitted through a packet of a different form than the packet exemplified in FIG. 8.

[0055] In the present disclosure, a broadcast stream group may refer to a plurality of broadcast streams having synchronized timing. For example, a broadcast stream group may include a broadcast isochronous group (BIG) according to the BLE specification, but may also include a group of data streams broadcast according to communication technologies other than BLE.

[0056] In the present disclosure, a device transmitting a broadcast stream or a group of broadcast streams may be referred to as a source device, and a device receiving a broadcast stream or a group of broadcast streams may be referred to as a sink device. The source device may be used interchangeably with transmitter, transmitting device, transmitting device, broadcaster, etc., and the sink device may be used interchangeably with receiver, receiving device, receiving device, observer, etc. The source device and the sink device may be briefly referred to as a device or an electronic device. Examples that do not limit the present disclosure include a television (TV), a desktop computer, a laptop computer, a smartphone, a microphone, etc., and a sink device may be a wireless earphone, earbud, wireless headset, smartwatch, speaker, hearing aid, etc.

[0057] A. Auracast TM

[0058] With the support for broadcast streams (e.g., BIS) starting from the Bluetooth® LE (BLE) standard, various applications or services utilizing broadcast streams are being introduced. For example, Auracast, which enables a source device to broadcast an audio stream to multiple sink devices using BLE technology. TM There is. Auracast TMAuracast was developed with the purpose of enabling audio sharing with others, allowing users to fully enjoy television in public places without muting, and providing the best sound quality regardless of location. TM In this context, devices can perform roles such as transmitters, receivers, and assistants. A transmitter refers to a device (or source device) that transmits a broadcast stream, a receiver refers to a device (or sink device) that receives a broadcast stream, and an assistant may refer to a device that configures and controls the receiver. For example, since a receiver, such as headphones, does not have a separate user interface (UI), the user can select a stream using the assistant and receive the stream using the receiver.

[0059] Figures 1a and 1b are Auracast TM Examples of broadcasting audio streams based on are illustrated. Figures 1a and 1b show Auracast TM This disclosure is merely an example to aid understanding and is not limited to the examples of FIGS. 1a and 1b. For example, in FIGS. 1a and 1b, the transmitter is exemplified as a microphone and a TV, respectively, but the transmitter may be other devices such as a desktop computer, a laptop computer, a smartphone, etc. Likewise, the receiver may be other devices, not limited to speakers, earsets, headphones, hearing aids, etc.

[0060] Referring to Fig. 1a, the microphone is Auracast TM Using BLE technology as a transmitter, you can broadcast audio streams, and multiple audiences can use Auracast TM You can receive audio streams using a receiver. For example, Auracast TMThe receiver may include headphones (Receiver #1 and Receiver #4), earbuds (Receiver #2), a hearing aid (Receiver #3), a cochlear implant (Receiver #5), and speakers (Receiver #6 and Receiver #7). Auracast TM The number of receivers is theoretically unlimited and can be determined by the number of audience members that can be accommodated in the space.

[0061] Referring to Fig. 1b, Auracast TM The number of transmitters can be multiple. In the example of FIG. 1b, three different TVs (TV #1, TV #2, TV #3) independently Auracast TM It can operate as a transmitter. For example, TV #1 can broadcast an audio stream related to a snooker game, TV #2 can broadcast an audio stream related to a darts game, and TV #3 can broadcast an audio stream related to a soccer game. In the example of Fig. 1b, three TVs (TV #1, TV #2, TV #3) are broadcasting different audio streams in a public place, but the user [can use] Auracast TM By using the receiver, you can listen to the desired audio stream in optimal condition. For example, the user of Receiver #1 and the user of Receiver #2 can enjoy a snooker match in optimal condition without muting TV #2 and TV #3. Similarly, the user of Receiver #3 can enjoy a darts match without muting TV #1 and TV #3, and the users of Receiver #4 and Receiver #5 can enjoy a soccer match without muting TV #1 and TV #2.

[0062] Auracast TM This is merely one example to which the present disclosure may be applied, and the present disclosure is Auracast TMThe present disclosure is not limited to being applicable only to systems that broadcast data wirelessly (using BLE technology). Furthermore, the present disclosure is not limited to being applicable only to broadcasting audio streams, but may also be applicable without limitation to broadcasting data streams such as video streams, digital content, application data, files, etc.

[0063] B. Channels and Channel Hopping

[0064] FIG. 2 illustrates a channel that can be used in the present disclosure.

[0065] In a Bluetooth® system, 40 channels may be used in the 2.4 GHz band with a spacing of 2 MHz. Channels may be referred to as RF (radio frequency) channels or physical channels. For example, the 40 channels may each have channel indices from 0 to 39, and the channel indices may indicate channels in the 2 MHz band from 2400 MHz to 2480 MHz. For example, among the 40 channels, three channels (e.g., channel indices 37, 38, and 39) may be primary advertising channels used for initial advertising, and the remaining 37 channels (e.g., channel indices 0 to 36) may be general-purpose channels used for data communication. Primary advertising channels may be briefly referred to as advertising channels, and general-purpose channels may be referred to as data channels.

[0066] FIG. 3 illustrates channel hopping that can be used in the present disclosure. As illustrated in FIG. 3, the device can perform channel hopping on a channel-by-channel basis, and channel hopping can be combined with frequency hopping.

[0067] In a Bluetooth® system, channel hopping may be used to avoid interference between devices. A device can transmit and / or receive data while performing channel hopping on data channels (e.g., 37 channels corresponding to channel indices 0 to 36 in FIG. 1).

[0068] When performing channel hopping, the next channel can be determined based on a channel selection algorithm (CSA). For example, a BLE system supports channel selection algorithm #1 or channel selection algorithm #2. Since such algorithms are described in detail in Bluetooth® Core Specification v5.4, a detailed description is omitted in this disclosure, and the entire contents of Bluetooth® Core Specification v5.4 are incorporated by reference in this disclosure. In this disclosure, channel selection algorithm #1 or channel selection algorithm #2 are not limited to use, and other channel selection algorithms may be used.

[0069] Channel Selection Algorithm #2 may be used when the source device broadcasts a data stream, and the channel to be used for channel hopping in Channel Selection Algorithm #2 can be calculated using a predefined algorithm between the devices. The channel selected by calculation in Channel Selection Algorithm #2 may appear semi-random and can be effective in avoiding interference with data channels used in the connections of other devices. When Channel Selection Algorithm #2 is used, channel indices can be generated using Channel Selection Algorithm #2 for isochronous events (e.g., CIS events or BIS events), periodic advertisement packets, and sub-events, and channel hopping can be performed according to the generated channel indices.

[0070] Referring to FIG. 3, when a source device broadcasts two data streams, a channel selection algorithm can be applied independently to the first data stream and the second data stream to perform channel hopping on the selected data channels. Since the first data stream and the second data stream can be transmitted and / or received using different channels, interference can be effectively avoided. FIG. 3 is merely an example, and the present disclosure is not limited to the example of FIG. 3.

[0071] C. Broadcast isochronous stream (BIS) and broadcast isochronous group (BIG)

[0072] BLE systems support isochronous streams (IS), such as connected isochronous streams (CIS) and broadcast isochronous streams (BIS). Acknowledgement (ACK) may be used for CIS, but may not be used for BIS. For example, a transmitter may transmit multiple independent and synchronized data streams, each of which may be referred to as an isochronous stream.

[0073] Figure 4 illustrates the procedure for establishing a BIS.

[0074] Referring to FIG. 4, the transmitter (or broadcaster) can transmit advertising packets on three main advertising channels (e.g., channels 37, 38, and 39). For example, the advertising packet may include an ADV_EXT_IND PDU (protocol data unit), and the ADV_EXT_IND PDU may indicate, through AUX pointer information (e.g., the AuxPtr field), that additional information about the BIS is included in an extended advertising packet transmitted on one of the general-purpose channels (e.g., channels 0 through 36).

[0075] For example, an extended ad packet may contain an AUX_ADV_IND PDU, and the AUX_ADV_IND PDU may contain synchronization information (e.g., a SyncInfo field) pointing to an AUX_SYNC_IND PDU. If a synchronization information field is present in the AUX_ADV_IND PDU, a receiver (or observer) may determine that a periodic advertising train containing the AUX_SYNC_IND PDU exists, and the periodic advertising train containing the AUX_SYNC_IND PDU may be transmitted and received at the time position indicated by the synchronization information field. The receiver may synchronize with the periodic advertising train using the synchronization information field included in the extended ad packet, and the periodic advertising train may be associated with a single BIG.

[0076] The AUX_SYNC_IND PDU may include an additional controller advertising data (ACAD) field, and the ACAD field may include BIG information (e.g., BIGInfo field), and the BIG information may include information regarding BIG and BIG timing. The receiver can obtain BIG information by synchronizing with a periodic advertising train and obtain essential information for synchronizing with the currently ongoing BIS.

[0077] AUX_EXT_IND, AUX_ADV_IND, and AUX_SYNC_IND are described in detail in Bluetooth® Core specification v5.4, and the present disclosure incorporates the entire Bluetooth® Core specification v5.4 by reference.

[0078] As detailed information regarding the Appearance Value and Local Name in FIG. 4 is described in detail in the Bluetooth® Core Specification Supplement (CSS), the Broadcast Name and Public Broadcast Announcement are described in detail in the Bluetooth® Public Broadcast Profile (PBP), the Broadcast Audio Announcement, Basic Audio Announcement, and BASE are described in detail in the Bluetooth® Basic Audio Profile (BAP), and the Program_Info LTV and Language LTV are described in detail in the Bluetooth® Assigned Numbers (AN) document, detailed description of these information is omitted in this disclosure. This disclosure incorporates the entire Bluetooth® CSS, PBP, BAP, and AN documents by reference.

[0079] FIG. 5 illustrates a format of BIG information that can be used in the present disclosure.

[0080] Referring to FIG. 5, BIG information (e.g., BIGInfo field) may be included in the ACAD field included in the AUX_SYNC_IND PDU transmitted during periodic advertising. The BIG information may have a length of 33 octets in the case of unencrypted BIG and a length of 57 octets in the case of encrypted BIG.

[0081] The BIG_Offset field may indicate a time offset from the start of a packet containing BIG information to the BIG anchor point (or the start time of a BIG event) pointed to by the BIG information. The value of the BIG_Offset field is the time unit indicated by the BIG_Offset_Units bit, and the actual time offset can be determined by multiplying the value of BIG_Offset by the time unit indicated by the BIG_Offset_Units bit. The time offset may be greater than 600 microseconds (μs). The BIG anchor point may not be earlier than the time offset and may not be later than one time unit added after the start of the associated packet.

[0082] The ISO_Interval field may indicate the time interval between two adjacent BIG anchor points (or the start times of two adjacent BIG events) and may be in units of 1.25 milliseconds (ms). The value of the ISO_Interval field may be between 4 and 3200 (i.e., between 5 ms and 4 seconds).

[0083] The Num_BIS field may indicate the number of BISs within a BIG, and the NSE(number of subevent) field may indicate the number of subevents per BIS within each BIG event. The value of the NSE field may be between 1 and 31 and may be an integer multiple of BN.

[0084] The BN field, PTO field, and IRC field may include variables that control retransmission, pretransmission, etc. in each BIG event. The value of the BN field may be between 1 and 7, the value of the PTO field may be between 0 and 15, and the value of the IRC field may be between 1 and 15.

[0085] The Sub_Interval field can indicate the time interval between the start times of two consecutive sub-events of BIS, and can be in microseconds.

[0086] The BIS_Spacing field can indicate the time interval between the start times of corresponding sub-events in adjacent BISs within a BIG, and can be in microseconds. Additionally, if a control sub-event exists, the BIS_Spacing field can indicate the time interval between the start times of the first sub-event of the last BIS and the control sub-event, and can be in microseconds.

[0087] The Max_PDU field may indicate the maximum number of data octets that can be transmitted in each packet (or BIS data PDU) in the BIG. The value of the Max_PDU field may be between 1 and 251 octets. The SeedAccessAddress field may indicate the seed access address (SAA) for the BIG. The access address for the BIS may be derived from the SAA. The SDU_Interval field may be between 0x0000FF and 0x0FFFFF and may be in microseconds. The Max_SDU field may indicate the maximum size of the service data unit (SDU) in the BIG. The value of the Max_SDU field may be between 1 and 4095 octets. The BaseCRCInit field may indicate the BaseCRCInit value. For a broadcast isochronous PDU, the shift register included in the cyclic redundancy check (CRC) generator can be pre-set with the BaseCRCInit value from the BIGInfo data of the top 2 octets and the BIS_Number for a specific BIS of the bottom octet.

[0088] The ChM field may include a channel map indicating used and unused data channels. All channels are represented by bits assigned according to the data channel index, where the least significant bit (LSB) represents data channel index 0 and the bit at position 36 represents data channel index 36. A bit value of 0 indicates that the channel is not in use, and a bit value of 1 indicates that the channel is in use. The bits at positions 37, 38, and 39 may be reserved for future use.

[0089] The PHY field may indicate the physical layer (PHY) used by the BIG, and the bisPayloadCount field may be used for the first sub-event of the BIG event indicated by the BIG_Offset field. The Framing field may be set if the BIG transmits framed data. If the BIG is encrypted, the GIV field may be a 64-bit parameter and the GSKD field may be a 128-bit parameter.

[0090] A detailed description of BIG information (e.g., BIGInfo fields) is provided in Bluetooth® Core Specification v5.4, and this disclosure incorporates the entire Bluetooth® Core Specification v5.4 by reference.

[0091] FIG. 6 illustrates a BIG event, a BIS event, and a BIS sub-event. FIG. 6 is for illustrative purposes only, and the BIG event, BIS event, and BIS sub-event that may be used in the present disclosure may have a structure different from FIG. 6.

[0092] A BIG may include one or more BISs. Multiple BISs included in a BIG may have a common timing reference based on a transmitter (or broadcaster) and may be synchronized in the time domain. For example, the left and right channels of an audio stereo stream received by individual devices need to be rendered simultaneously. Multiple BISs included in a BIG may be arranged sequentially or interleavedly.

[0093] A BIS may be a logical transport used to deliver one or more isochronous data streams to all devices for the BIS within a specific range. The BIS may include one or more sub-events for transmitting isochronous data packets. A sub-event may include a time interval during which at least one synchronized receiver can receive a broadcast packet (or broadcast isochronous PDU). The BIS may be transmitted and received as an isochronous data packet in each BIS sub-event. For the BIS, no ACK (acknowledgement) is used, and data traffic is unidirectional from the broadcaster.

[0094] Referring to FIG. 6, a BIG event x may include at least one BIS event x, and a BIS event x may include one or more sub-events. An isochronous data packet may be transmitted in each sub-event. ISO_Interval represents the time interval between two adjacent BIG anchor points (or the start times of two adjacent BIG events), and Sub_Interval represents the time interval between the start times of two consecutive sub-events in the BIS (e.g., see FIG. 5 and related description). A BIS event may include one or more BIS PDUs. A BIG event may include a control sub-event, and the BIS event may be determined based on the Num_BIS field of the BIG information, and the control sub-event may be located after the BIS event ends.

[0095] When the source device changes channel information, it may transmit a control sub-event containing the changed channel information. When the channel information does not change, the source device may not transmit a control sub-event. When the source device terminates the BIG, it may transmit a control sub-event. Each BIS event may start at a BIS anchor point and end at the last sub-event. Each BIG event may start at a BIG anchor point, terminate after the control sub-event if a control sub-event exists, and terminate at the last BIS event if no control sub-event exists. BIG anchor points may be regularly spaced at ISO_Interval intervals.

[0096] Figures 7a and 7b illustrate an example where BIG includes multiple BIS.

[0097] BIS within a BIG can be arranged in a sequential or interleaved manner by setting the values ​​of the Sub_Interval field and the BIS_Spacing field of the BIG information (e.g., BIGInfo field). FIG. 7a illustrates an example where BIS within a BIG is arranged sequentially, and FIG. 7b illustrates an example where BIS within a BIG is arranged interleavedly. FIG. 7a and FIG. 7b are for illustrative purposes only, and the present disclosure is not limited to the examples of FIG. 7a and FIG. 7b. For example, the present disclosure may be applied in the same way even if the number, length, or structure of BIG events, BIS events, and BIS sub-events changes.

[0098] Referring to FIG. 7a, an example is illustrated in which Num_BIS=2 and NSE=2 are set in the BIG information, and BIS1 and BIS2 are arranged sequentially. BIG event x sequentially includes BIS1 event x and BIS2 event x, BIS1 event x includes BIS1 sub-event 1 (BIS1 Event x Subevt 1) and BIS1 sub-event 2 (BIS1 Event x Subevt 2), and BIS2 event x may include BIS2 sub-event 1 (BIS2 Event x Subevt 1) and BIS2 sub-event 2 (BIS2 Event x Subevt 2). In the case of sequential arrangement, BIS_Spacing may be greater than or equal to NSE * Sub_Interval, and all sub-events of BIS Event may be arranged sequentially within BIS_Spacing.

[0099] Referring to FIG. 7b, an example is illustrated in which Num_BIS=2 and NSE=2 are set in the BIG information, and BIS1 and BIS2 within the BIG are interleaved. BIG event x may include BIS1 event x and BIS2 event x in an interleaved manner. BIG event x may include BIS1 sub-event 1 (BIS1 Event x Subevt 1), BIS2 sub-event 1 (BIS2 Event x Subevt 1), BIS1 sub-event 2 (BIS1 Event x Subevt 2), and BIS2 sub-event 2 (BIS2 Event x Subevt 2) in chronological order. For the interleaved arrangement, Sub_Interval may be Num_BIS * BIS_Spacing, and the first sub-event of all BIS may be arranged, followed by the second sub-event of all BIS.

[0100] Referring to FIGS. 7a and 7b, the maximum possible time length for data transmission of a BIG event can be denoted by BIG_Sync_Delay. The value of BIG_Sync_Delay may be equal to the time from the anchor point to the BIG Synchronization Point, which is the end of the packet containing the payload of Max_PDU octets transmitted in the last sub-event. For example, it may be determined based on BIG_Sync_Delay = (Num_BIS - 1) * BIS_Spacing + (NSE - 1) * Sub_Interval + MPT. MPT may represent the time required to transmit a packet containing a BIS data PDU along with the payload of Max_PDU octets in the PHY used for the BIS. The start position of the control sub-event within the BIG may be determined by BIG_Control_Offset.

[0101] FIG. 8 illustrates a packet structure that may be used in the present disclosure. The packet structure of FIG. 8 is merely an example, and the present disclosure is not limited to the packet structure of FIG. 8, and other packet structures may be used. For example, the example of FIG. 8 may be a packet structure for LE Uncoded 1M and LE 2M, and the present disclosure may use a packet structure for LE Coded.

[0102] Referring to FIG. 8, isochronous data may be transmitted by being included in the payload (814) of an isochronous physical channel PDU (810). In this disclosure, the isochronous physical channel PDU (810) may be briefly referred to as an ISO PDU. When the isochronous data is encrypted, the ISO PDU (810) may include a message integrity check (MIC) field (816). The header (812) of the ISO PDU (810) may include information regarding a logical transport and a logical link. The ISO PDU (810) may be included in a packet (800) that includes a preamble (802), an access address (804), and a Cyclic Redundancy Code (CRC) (806).

[0103] The preamble (802) may include 1 octet for LE 1M PHY and 2 octets for LE 2M PHY. The access address (804) may include 4 octets, the ISO PDU (810) may include 2 to 258 octets, and the CRC (806) may include 3 octets.

[0104] In the present disclosure, the term packet may refer to a packet (800) having the structure illustrated in FIG. 8, or to an ISO PDU (810). Alternatively, in the present disclosure, packet may refer to a packet for LE Coded.

[0105] D. Technical Problems of Broadcast-Based Transmission

[0106] As explained earlier, broadcast-based transmission (e.g., Auracast TM In the case of ), ACK (acknowledgement) is not used. Therefore, broadcast-based transmission may not guarantee a reception rate, may result in a low PDR (packet delivery ratio), and may cause technical problems that result in a low quality of user experience.

[0107] To address the technical issues of broadcast-based transmission, one might consider introducing ACK into broadcast-based transmission; however, due to the nature of broadcast-based transmission, there is no limit to the number of receivers, so the number of receivers receiving the broadcast-based transmission cannot be known. Therefore, introducing ACK into broadcast-based transmission may not be appropriate.

[0108] Furthermore, to address the technical issues of broadcast-based transmission, one could consider performing a certain number of unconditional retransmissions (without introducing ACKs); however, increasing retransmissions to raise the PDR can lead to technical problems that waste the transmitter's time resources. For example, Auracast, which utilizes broadcast-based transmission TM In this case, it is required to retransmit packets up to 4 times (without ACK) to ensure minimum quality. Increasing the number of retransmissions can increase the PDR, but due to time resource constraints, the number of streams that a single transmitter can broadcast may be limited.

[0109] Furthermore, in systems that transmit signals wirelessly, coverage may be limited by the transmitter's transmission range. If the transmitter's performance is poor, the limited coverage area over which the transmitter can transmit signals can lead to a deterioration in reception rate, PDR, and the quality of the user experience. While coverage can be increased by installing multiple synchronized transmitters, doing so not only entails high economic costs but can also lead to complexity in operation.

[0110] E. The proposed method of the present disclosure

[0111] The present disclosure proposes a method utilizing negative acknowledgment (NACK) and retransmission between receivers receiving a broadcast stream to solve the technical problems of the broadcast-based transmission described above. More specifically, the present disclosure proposes a method to improve the PDR and reception quality for broadcast-based transmission and to expand the coverage of a transmitter by allowing NACK and retransmission for the data of the first broadcast stream to be performed between receivers receiving the first broadcast stream during the transmission time of the second broadcast stream, in a situation where a transmitter transmits a plurality of broadcast streams including a first broadcast stream and a second broadcast stream.

[0112] For clarity and convenience of explanation in this disclosure, a NACK transmitted / received between receivers receiving a broadcast stream may be referred to as a "local NACK," and a retransmission performed between receivers receiving a broadcast stream may be referred to as a "local retransmission."

[0113] To aid in understanding the present disclosure, the description assumes a situation where a single source device broadcasts two broadcast streams; however, the present disclosure may be equally applied to situations where each of multiple source devices broadcasts two or more broadcast streams. Additionally, the present disclosure assumes a situation where multiple receivers receive broadcast streams.

[0114] For example, the present disclosure is Auracast TM One can assume a situation where one or more transmitters broadcast two or more BIS signals, as in a system (e.g., see FIG. 1a and 1b), and two or more receivers receive at least one of the two or more BIS signals. Auracast TMThis is merely one example to which the present disclosure may be applied, and the present disclosure is Auracast TM In addition, it can be applied without limitation to scenarios where two or more broadcast streams are transmitted by a single transmitter. For the sake of understanding, the present disclosure is described by assuming a BIS, but in the present disclosure, a BIS can be generalized to a broadcast stream.

[0115] FIG. 9 illustrates an example of a system to which the present disclosure may be applied. FIG. 9 is merely an example to aid in understanding the present disclosure, and the present disclosure is not limited to the example of FIG. 9.

[0116] Referring to FIG. 9, an example is illustrated in which a single source device (0-a) transmits multiple broadcast streams. For example, the source device (0-a) is Auracast TM It may be a transmitter or a transmitter that supports BLE standards, but it may also be a transmitter that supports other communication technologies. Additionally, the source device (0-a) may be a device of a type other than a TV. In the example of FIG. 9, the source device (0-a) may transmit two different language broadcast streams (e.g., English, Spanish) for the same video stream, and depending on the user's choice, the sink device (1-1, 1-2, ..., 1-N, 2-1, 2-2, ..., 2-M) may receive one of the two broadcast streams. For example, depending on the user's choice, the sink device (1-1, 1-2, ..., 1-N) may receive a broadcast stream containing English audio, and depending on the user's choice, the sink device (2-1, 2-2, ..., 2-M) may receive a broadcast stream containing Spanish audio.

[0117] According to the method proposed in the present disclosure, local NACK transmission and local retransmission can be performed between sink devices (1-1, 1-2, ..., 1-N) that receive an English broadcast stream through a channel different from the channel through which the Spanish broadcast stream is transmitted during the time interval in which the Spanish broadcast stream is transmitted. Accordingly, according to the method proposed in the present disclosure, since data of a broadcast stream that was not successfully received can be retransmitted between receivers using the time interval in which another broadcast stream is transmitted, the method proposed in the present disclosure does not require changing the operation of the transmitter and does not affect the operation of the transmitter. According to the method proposed in the present disclosure, technical effects can be expected to effectively improve the low PDR and low quality of broadcast-based transmissions in which ACKs are not used through retransmission between receivers.

[0118] Furthermore, according to the method proposed in this disclosure, since local NACK and local retransmission are utilized between receivers, not only is there no need to introduce ACK into broadcast-based transmission, but there is also no need to increase the number of unconditional retransmissions (performed without ACK) at the transmitter side. For example, Auracast TMIn the case of [the present invention], it is required to unconditionally retransmit packets up to four times; however, according to the method proposed in the present disclosure, the PDR and reception quality of broadcast-based transmission can be effectively improved without increasing the number of unconditional retransmissions. Rather, according to the method proposed in the present disclosure, since unreceived packets can be exchanged using local NACKs and local retransmissions between receivers, a technical effect of reducing the number of unconditional retransmissions by the transmitter can be expected. Furthermore, according to the method proposed in the present disclosure, since the number of unconditional retransmissions on the transmitter side can be maintained or reduced, a technical effect of maintaining or increasing the number of broadcast streams that can be transmitted within a given time resource can be expected.

[0119] Furthermore, according to the method proposed in the present disclosure, since local retransmission is performed between receivers, a receiver outside the transmitter's coverage can also receive data from a receiver within the transmitter's coverage through local retransmission between a receiver outside the transmitter's coverage and a receiver within the transmitter's coverage. Therefore, according to the method proposed in the present disclosure, a technical effect of expanding the transmitter's coverage can also be expected.

[0120] The proposed method of the present disclosure will be specifically explained below using examples.

[0121] FIGS. 10a and FIGS. 10b illustrate an example in which the proposed method of the present disclosure is applied to a group of broadcast streams arranged sequentially according to one embodiment of the present disclosure. FIGS. 10a and FIGS. 10b are merely examples to aid in understanding the present disclosure and are not intended to limit the present disclosure. Even if the number of source devices, the number of sink devices, the number of BIS, the number of BIS sub-events, etc., in the example of FIGS. 10a and FIGS. 10b are changed, the present disclosure can be applied in the same principle. As an example that does not limit the present disclosure, the source device (0-a) may be the source device (0-a) of FIG. 9, the sink devices (1-a, 1-b) may be two of the sink devices (1-1, 1-2, ..., 1-N) of FIG. 9, and the sink devices (2-a, 2-b) may be two of the sink devices (2-1, 2-2, ..., 2-M) of FIG. 9.

[0122] Referring to FIG. 10a, an example of the proposed method of the present disclosure being applied to the BIG event x of FIG. 7a is illustrated. In the example of FIG. 10a, it is assumed that device (0-a) broadcasts two broadcast streams (BIS1, BIS2) in a sequential manner, devices (1-a, 1-b) receive BIS1, and devices (2-a, 2-b) receive BIS2. Device (0-a) can transmit the first data (1011) and the second data (1012) of BIS1 in BIS1 sub-event 1 and BIS1 sub-event 2, respectively, and transmit the first data (1013) and the second data (1014) of BIS2 in BIS2 sub-event 1 and BIS2 sub-event 2, respectively. The device (0-a) can perform channel hopping on a sub-event basis to transmit data (1011, 1012) of BIS1 and data (1013, 1014) of BIS2 through different channels (Ch n1, Ch n2, Ch n3, Ch n4). For example, the device (0-a) can perform channel hopping based on a channel selection algorithm (e.g., channel selection algorithm #2) (e.g., see "B. Channels and Channel Hopping" of the present disclosure).

[0123] In the example of FIG. 10a, it is assumed that in BIS1 sub-event 1, device (1-a) successfully receives the first data (1011) of BIS1 and device (1-b) fails to receive the first data (1011), and in BIS1 sub-event 2, device (1-a) fails to receive the second data (1012) of BIS1 and device (1-b) successfully receives the second data (1012). Since device (1-b) did not successfully receive the first data (1011) of BIS1 in BIS1 sub-event 1, device (1-b) may transmit a local NACK (1021) in a time interval (1003) related to BIS2 (corresponding to BIS1 sub-event 1) according to the method proposed in the present disclosure.

[0124] In the example of FIG. 10a, since the device (0-a) transmits the first data (1011) through the channel (Ch n1) in BIS1 sub-event 1, then hops to the next channel (Ch n2) in BIS1 sub-event 2, and then transmits the second data (1012), the channel (Ch n1) for BIS1 sub-event 1 (or the first data of BIS1) (1011) may not be used in the time interval (1003). Accordingly, the device (1-b) can transmit a local NACK (1021) through the channel (Ch n1) for BIS1 sub-event 1 (or the first data of BIS1) (1011) in the time interval (1003) associated with BIS2 (corresponding to BIS1 sub-event 1).

[0125] Device (1-a) can detect a local NACK through a channel (Ch n1) for BIS1 sub-event 1 (or the first data of BIS1) (1011) in a time interval (1003) related to BIS2 (corresponding to BIS1 sub-event 1) because it has successfully received the first data (1011) of BIS1 in BIS1 sub-event 1. The local NACK according to the proposed method of the present disclosure can be transmitted and received between devices (1-a, 1-b) receiving a broadcast stream (e.g., BIS1). When device (1-a) detects a local NACK (1021) in the time interval (1003), it can perform a local retransmission (1031) through a channel (Ch k1) for the data (1011) received in BIS1 sub-event 1. Device (1-b) can receive the first data (1011) of BIS1 that failed to be received in BIS1 sub-event 1 through local retransmission (from device (1-a)) in the time interval (1003).

[0126] Similarly, since device (1-a) did not successfully receive the second data (1012) of BIS1 in BIS1 sub-event 2, device (1-a) may transmit a local NACK (1022) in a time interval (1004) related to BIS2 (corresponding to BIS1 sub-event 2) according to the method proposed in the present disclosure. Since device (1-b) successfully received the second data (1012) of BIS1 in BIS1 sub-event 2, device (1-b) may perform detection of a local NACK in a time interval (1004) related to BIS2. When device (1-b) detects a local NACK (1022) in a time interval (1004), it may perform local retransmission (1032) through a channel (Ch k2) for the data (1012) received in BIS1 sub-event 2. Device (1-a) can receive the second data (1012) of BIS1 that failed to be received in BIS1 sub-event 2 through local retransmission (from device (1-b)) in the time interval (1004).

[0127] The local NACK (1021, 2022) according to the proposed method of the present disclosure may be transmitted using an energy detection method. A receiver (1-a, 1-b) may determine that it has received or detected the NACK if it detects the energy of a signal through a specific channel during a specific time interval, and may determine that it has not received or detected the NACK if it does not detect the energy of the signal. The energy detection method is not the only method that can be used for transmitting the local NACK (1021, 2022) according to the proposed method of the present disclosure, and other methods may be used for transmitting the local NACK, such as a method of transmitting the NACK information by including it in a specific packet format.

[0128] In the proposed method of the present disclosure, the channels (Ch k1, Ch k2) for local retransmission (1031, 1032) and the channels (Ch n3, Ch n4) for BIS2 sub-events (or data) (1013, 1014) may be determined as different channels. For example, the channels for local retransmission (Ch k1, Ch k2) may be calculated through a new channel selection algorithm related to the transmission channels of BIS1. For example, the new channel selection algorithm may include applying a hop increasement from the channels for BIS1 sub-events 1, 2 (or the first data, second data of BIS1) (1011, 1012). As a more specific example, the index (k1) of the channel for local retransmission (1031) may be determined based on the index (n1) of the channel for BIS1 sub-event 1 (or the first data of BIS1) (1011) and the value (n1+d) of a fixed hop increment value (d), and the index (k2) of the channel for local retransmission (1032) may be determined based on the index (n2) of the channel for BIS1 sub-event 2 (or the second data of BIS1) (1012) and the value (n2+d) of a fixed hop increment value (d). If the value of the sum of the hop increment values ​​(n1+d, n2+d) exceeds the maximum value of the channel index (e.g., 36), it may be wrapped around using a modulo operation (e.g., modulo 37).

[0129] When BIGs are arranged sequentially as in the example of FIG. 10a, time intervals (1001, 1002, 1003, 1004, 1005, 1006) can be identified based on Sub_Interval and BIS_Spacing (e.g., see description of BIG information in FIG. 5). For example, when BIGs are arranged sequentially, time intervals (1001, 1003, 1005) may correspond to Sub_Interval, and time intervals (1002, 1004, 1006) may correspond to BIS_Spacing - Sub_Interval.

[0130] Referring again to FIG. 10a, it is assumed that in BIS2 sub-event 1, device (2-a) successfully receives the first data (1013) of BIS2 and device (2-b) fails to receive the first data (1013), and in BIS2 sub-event 2, device (2-a) fails to receive the second data (1014) of BIS2 and device (2-b) successfully receives the second data (1014). Since device (2-b) did not successfully receive the first data (1013) of BIS2 in BIS2 sub-event 1, according to the method proposed in the present disclosure, device (2-b) can transmit a local NACK (1023) through a channel (Ch n3) for BIS2 sub-event 1 in a time interval (1005) (corresponding to BIS2 sub-event 1). Device (2-a) can detect a local NACK in the time interval (1005) because it has successfully received the first data (1013) of BIS2 in BIS2 sub-event 1. The local NACK according to the proposed method of the present disclosure can be transmitted and received between devices (2-a, 2-b) receiving a broadcast stream (e.g., BIS2). When device (2-a) detects a local NACK (1023) in the time interval (1005), it can perform local retransmission (1033) through the channel (Ch k3) for the data (1013) received in BIS2 sub-event 1. Device (2-b) can receive the first data (1013) of BIS2 that it failed to receive in BIS2 sub-event 1 through local retransmission (from device (2-a)) in the time interval (1005).

[0131] Similarly, since device (2-a) did not successfully receive the second data (1014) of BIS2 in BIS2 sub-event 2, device (2-a) may transmit a local NACK (1024) in a time interval (1006) (corresponding to BIS2 sub-event 2) according to the method proposed in the present disclosure. Since device (2-b) successfully received the second data (1014) of BIS2 in BIS2 sub-event 2, device (2-b) may perform detection of a local NACK in a time interval (1006). When device (2-b) detects a local NACK (1024) in a time interval (1006), it may perform local retransmission (1034) through a channel (Ch k4) for the data (1014) received in BIS2 sub-event 2. Device (2-a) can receive the second data (1014) of BIS2 that failed to be received in BIS2 sub-event 2 through local retransmission (from device (2-b)) in the time interval (1006).

[0132] As previously explained, as an example not limiting the present disclosure, local NACK (1023, 1024) can be transmitted and received via an energy detection method, and channels (Ch k3, Ch k4) for local retransmission (1033, 1034) can be calculated via a new channel selection algorithm associated with the transmission channels of BIS2. In an example that does not limit the present disclosure, when applying a hop increase, the index of the channel (k3) for local retransmission (1033) may be determined based on the index of the channel (n3) for BIS2 sub-event 1 (or the first data of BIS2) (1013) and the value of a predetermined hop increase (d) (n3+d), and the index of the channel (k4) for local retransmission (1034) may be determined based on the index of the channel (n4) for BIS2 sub-event 2 (or the second data of BIS2) (1014) and the value of a predetermined hop increase (d) (n4+d). If the value of the sum of the hop increase (n3+d, n4+d) exceeds the maximum value of the channel index (e.g., 36), it may be wrapped around using a modulo operation (e.g., modulo 37).

[0133] Referring again to FIG. 10a, if BIG event x does not include a control sub-event, BIG event x may end at the end of BIS2 sub-event 2 because BIS2 sub-event 2 is the last sub-event within BIG event x. However, if the time interval (e.g., ISO_Interval) between the start times of two adjacent BIG events (or two adjacent BIG anchor points) is set sufficiently long, local NACK and local retransmission may be performed in the time interval from the end of the last sub-event within BIG event x (e.g., BIS2 sub-event 2) to the start time of the next BIG event x+1. In the method proposed in the present disclosure, the time interval (e.g., ISO_Interval) between the start times of two adjacent BIG events (or two adjacent BIG anchor points) may be set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing.

[0134] Referring to FIG. 10b, an example of the proposed method of the present disclosure being applied to the BIG event x+1 of FIG. 7a is illustrated. In contrast to the example of FIG. 10a, the example of FIG. 10b differs in that the device (0-a) transmits a control sub-event at the end of the BIG event x+1. When a control sub-event is transmitted at the end of the BIG event, in order to support local NACK and local retransmission according to the proposed method of the present disclosure, it is necessary to set a sufficiently long time offset (e.g., BIG_Control_Offset) from the end of the last sub-event (e.g., BIS2 sub-event 2) within the BIG event x+1 to the start of the control sub-event. If the BIG event includes a control sub-event, in the proposed method of the present disclosure, the time offset (e.g., BIG_Control_Offset) from the end of the last sub-event within the BIG event to the start of the control sub-event may be set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing.

[0135] Since the local NACK and local retransmission according to the proposed method of the present disclosure can be applied to FIG. 10b by the same principle as described in the example of FIG. 10a, the entire description of FIG. 10a is included herein by reference. In the description of FIG. 10a, BIG event x can be replaced with BIG event x+1 of FIG. 10b, and in the description of FIG. 10a, the time intervals (1001, 1002, 1003, 1004, 1005, 1006) can be replaced with the time intervals (1007, 1008, 1009, 100a, 100b, 100c) of FIG. 10a, and in the description of FIG. 10a, the channels (Ch n1, Ch n2, Ch n3, Ch n4) can be replaced with the channels (Ch n5, Ch n6, Ch n7, Ch n8) of FIG. 10b, and in the description of FIG. 10a, the first data (1011) and second data (1012) of BIS1 and the first data (1013) and second data (1014) of BIS2 are of FIG. 10b The first data (1015) and second data (1016) of BIS1 and the first data (1017) and second data (1018) of BIS2 can be replaced, and the local NACK (1021, 1022, 1023, 1024) in the description of FIG. 10a can be replaced with the local NACK (1025, 1026, 1027, 1028) of FIG. 10b, and the local retransmission (1031, 1032, 1033, 1034) in the description of FIG. 10a can be replaced with the local retransmission (1035, 1036, 1037, 1038) of FIG. 10b, and the channels for local retransmission (Ch k1, Ch k2, Ch k3, Ch k4) in the description of FIG. 10a are the local It can be replaced with channels for retransmission (Ch k5, Ch k6, Ch k7, Ch k8).

[0136] FIGS. 11a and FIGS. 11b illustrate an example in which the proposed method of the present disclosure is applied to a group of broadcast streams arranged in an interleaved manner according to one embodiment of the present disclosure. FIGS. 11a and FIGS. 11b are merely examples to aid in understanding the present disclosure and are not intended to limit the present disclosure. Even if the number of source devices, the number of sink devices, the number of BIS, the number of BIS sub-events, etc., in the example of FIGS. 11a and FIGS. 11b are changed, the present disclosure can be applied in the same principle. As an example that does not limit the present disclosure, the source device (0-a) may be the source device (0-a) of FIG. 9, the sink devices (1-a, 1-b) may be two of the sink devices (1-1, 1-2, ..., 1-N) of FIG. 9, and the sink devices (2-a, 2-b) may be two of the sink devices (2-1, 2-2, ..., 2-M) of FIG. 9.

[0137] Referring to FIG. 11a, an example of the proposed method of the present disclosure being applied to the BIG event x of FIG. 7b is illustrated. In the example of FIG. 11a, it is assumed that device (0-a) broadcasts two broadcast streams (BIS1, BIS2) in an interleaved manner, devices (1-a, 1-b) receive BIS1, and devices (2-a, 2-b) receive BIS2. Device (0-a) can transmit the first data (110a) of BIS1 in BIS1 sub-event 1, transmit the first data (1112) of BIS2 in BIS2 sub-event 1, transmit the second data (1113) of BIS1 in BIS1 sub-event 2, and transmit the second data (1114) of BIS2 in BIS2 sub-event 2. The device (0-a) can perform channel hopping on a sub-event basis to transmit the first data (110a) of BIS1, the first data (1112) of BIS2, the second data (1113) of BIS1, and the second data (1114) of BIS2 through different channels (Ch n1, Ch n2, Ch n3, Ch n4). For example, the device (0-a) can perform channel hopping based on a channel selection algorithm (e.g., channel selection algorithm #2) (e.g., see "B. Channels and Channel Hopping" of the present disclosure).

[0138] In the example of FIG. 11a, it is assumed that in BIS1 sub-event 1, device (1-a) successfully receives the first data (110a) of BIS1 and device (1-b) fails to receive the first data (110a). Since device (1-b) did not successfully receive the first data (110a) of BIS1 in BIS1 sub-event 1, device (1-b) can transmit a local NACK (1121) in a time interval (1102) related to BIS2 (corresponding to BIS1 sub-event 1) according to the method proposed in the present disclosure. Since device (1-a) successfully received the first data (110a) of BIS1 in BIS1 sub-event 1, detection of the local NACK can be performed in a time interval (1102) related to BIS2. A local NACK according to the proposed method of the present disclosure may be transmitted and received between devices (1-a, 1-b) receiving a broadcast stream (e.g., BIS1). When device (1-a) detects a local NACK (1121) in a time interval (1102), it may perform a local retransmission (1131) through a channel (Ch k1) for the data (110a) received in BIS1 sub-event 1. Device (1-b) may receive the first data (110a) of BIS1 that failed to be received in BIS1 sub-event 1 through a local retransmission (from device (1-a)) in the time interval (1102).

[0139] Referring again to FIG. 11a, it is assumed that in BIS1 sub-event 2, device (1-a) fails to receive the second data (1113) of BIS1, and device (1-b) successfully receives the second data (1113). Since device (1-a) failed to successfully receive the second data (1113) of BIS1 in BIS1 sub-event 2, device (1-a) can transmit a local NACK (1123) in a time interval (1104) related to BIS2 (corresponding to BIS1 sub-event 2) according to the proposed method of the present disclosure. Since device (1-b) successfully received the second data (1113) of BIS1 in BIS1 sub-event 2, it can perform detection of a local NACK in a time interval (1104) related to BIS2 (corresponding to BIS1 sub-event 2). When the device (1-b) detects a local NACK (1123) in the time interval (1104), it can perform local retransmission (1133) through the channel (Ch k3) for the data (1113) received in BIS1 sub-event 2. The device (1-a) can receive the second data (1113) of BIS1 that failed to be received in BIS1 sub-event 2 through local retransmission (from the device (1-b)) in the time interval (1104).

[0140] As described with reference to FIG. 10a, in the proposed method of the present disclosure, local NACKs (1121, 1123) can be transmitted and received through an energy detection method, but other methods may be used for other local NACKs (1121, 1123).

[0141] Additionally, as described with reference to FIG. 10a, in the proposed method of the present disclosure, channels (Ch k1, Ch k3) for local retransmission (1131, 1133) may be calculated through a new channel selection algorithm associated with the transmission channels of BIS1. In an example that does not limit the present disclosure, when a hop increment is applied, the index (k1) of the channel for local retransmission (1131) may be determined based on the index (n1) of the channel for BIS1 sub-event 1 (or the first data of BIS1) (110a) and the value (n1+d) of a predetermined hop increment value (d), and the index (k3) of the channel for local retransmission (1133) may be determined based on the index (n3) of the channel for BIS1 sub-event 2 (or the second data of BIS1) (1113) and the value (n3+d) of a predetermined hop increment value (d). If the sum of the hop increment values ​​(n1+d, n3+d) exceeds the maximum channel index value (e.g., 36), it can be wrapped around using modulo operation (e.g., modulo 37).

[0142] When BIGs are arranged in an interleaved manner as in the example of FIG. 11a, time intervals (1101, 1102, 1103, 1104, 1105, 1106) can be identified based on Sub_Interval and BIS_Spacing (e.g., see description of BIG information in FIG. 5). For example, time intervals (1101, 1103, 1105) may correspond to BIS_Spacing, and time intervals (1102, 1104) may correspond to Sub_Interval - BIS_Spacing.

[0143] Referring again to FIG. 11a, it is assumed that in BIS2 sub-event 1, device (2-a) successfully receives the first data (1112) of BIS2, and device (2-b) fails to receive the first data (1112). Since device (2-b) did not successfully receive the first data (1112) of BIS2 in BIS2 sub-event 1, according to the method proposed in the present disclosure, device (2-b) can transmit a local NACK (1122) in a time interval (1103) related to BIS1 (corresponding to BIS2 sub-event 1). Since device (2-a) successfully received the first data (1112) of BIS2 in BIS2 sub-event 1, it can perform detection of a local NACK in the time interval (1103). A local NACK according to the proposed method of the present disclosure may be transmitted and received between devices (2-a, 2-b) receiving a broadcast stream (e.g., BIS2). When device (2-a) detects a local NACK (1122) in a time interval (1103), it may perform a local retransmission (1132) through a channel (Ch k2) for the data (1112) received in BIS2 sub-event 1. Device (2-b) may receive the first data (1112) of BIS2 that failed to be received in BIS2 sub-event 1 through a local retransmission (from device (2-a)) in the time interval (1103).

[0144] Referring again to FIG. 11a, it is assumed that in BIS2 sub-event 2, device (2-a) fails to receive the second data (1114) of BIS2, and device (2-b) successfully receives the second data (1114). Since device (2-a) failed to successfully receive the second data (1114) of BIS2 in BIS2 sub-event 2, device (2-a) can transmit a local NACK (1124) in a time interval (1105) (corresponding to BIS2 sub-event 2) according to the method proposed in the present disclosure. Since device (2-b) successfully received the second data (1114) of BIS2 in BIS2 sub-event 2, it can perform detection of the local NACK in the time interval (1105). When the device (2-b) detects a local NACK (1124) in the time interval (1105), it can perform local retransmission (1134) through the channel (Ch k4) for the data (1114) received in the BIS2 sub-event 2. The device (2-a) can receive the second data (1114) of BIS2 that failed to be received in the BIS2 sub-event 2 through local retransmission (from the device (2-b)) in the time interval (1105).

[0145] As previously explained, as an example not limiting the present disclosure, local NACKs (1122, 1124) may be transmitted and received via an energy detection method (e.g., see FIG. 10a and related description), and channels (Ch k2, Ch k4) for local retransmission (1132, 1134) may be calculated via a new channel selection algorithm associated with the transmission channels of BIS2. In an example that does not limit the present disclosure, when applying a hop increase, the index (k2) of the channel for local retransmission (1132) may be determined based on the index (n2) of the channel for BIS2 sub-event 1 (or the first data of BIS2) (1112) and the value (n2+d) of a predetermined hop increase value (d), and the index (k4) of the channel for local retransmission (1134) may be determined based on the index (n4) of the channel for BIS2 sub-event 2 (or the second data of BIS2) (1114) and the value (n4+d) of a predetermined hop increase value (d). If the value of the sum of the hop increase values ​​(n2+d, n4+d) exceeds the maximum value of the channel index (e.g., 36), it may be wrapped around using a modulo operation (e.g., modulo 37).

[0146] As described with reference to FIG. 10a, if BIG event x does not include a control sub-event, BIG event x may end at the end of BIS2 sub-event 2 because BIS2 sub-event 2 is the last sub-event within BIG event x. However, if the time interval (e.g., ISO_Interval) between the start times of two adjacent BIG events (or two adjacent BIG anchor points) is set sufficiently long, local NACK and local retransmission may be performed in the time interval from the end of the last sub-event (e.g., BIS2 sub-event 2) within BIG event x to the start time of the next BIG event x+1. In the method proposed in this disclosure, the time interval (e.g., ISO_Interval) between the start times of two adjacent BIG events (or two adjacent BIG anchor points) may be set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing.

[0147] Referring to FIG. 11b, an example of the proposed method of the present disclosure being applied to the BIG event x+1 of FIG. 7b is illustrated. In contrast to the example of FIG. 11a, the example of FIG. 11b differs in that the device (0-a) transmits a control sub-event at the end of the BIG event x+1. When a control sub-event is transmitted at the end of the BIG event, in order to support local NACK and local retransmission according to the proposed method of the present disclosure, it is necessary to set a sufficiently long time offset (e.g., BIG_Control_Offset) from the end of the last sub-event (e.g., BIS2 sub-event 2) within the BIG event x+1 to the start of the control sub-event. In the proposed method of the present disclosure, if a BIG event includes a control sub-event, the time offset (e.g., BIG_Control_Offset) from the end of the last sub-event within the BIG event to the start of the control sub-event may be set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing.

[0148] Since the local NACK and local retransmission according to the proposed method of the present disclosure can be applied to FIG. 11b by the same principle as described in the example of FIG. 11a, the entire description of FIG. 11a is included herein by reference. In the description of FIG. 11a, BIG event x can be replaced with BIG event x+1 of FIG. 11b, the time intervals (1101, 1102, 1103, 1104, 1105) in the description of FIG. 11a can be replaced with the time intervals (1106, 1107, 1108, 1109, 110a) of FIG. 11b, the channels (Ch n1, Ch n2, Ch n3, Ch n4) in the description of FIG. 11a can be replaced with the channels (Ch n5, Ch n6, Ch n7, Ch n8) of FIG. 11b, and in the description of FIG. 11a, the first data (1111) and second data (1113) of BIS1 and the first data (1112) and second data (1114) of BIS2 are the first data (1115) of BIS1 in FIG. 11b, The second data (1117) can be replaced with the first data (1116) and second data (1118) of BIS2, and the local NACK (1121, 1122, 1123, 1124) in the description of FIG. 11a can be replaced with the local NACK (1125, 1126, 1127, 1128) of FIG. 11b, and the local retransmission (1131, 1132, 1133, 1134) in the description of FIG. 11a can be replaced with the local retransmission (1135, 1136, 1137, 1138) of FIG. 11b, and the channels for local retransmission (Ch k1, Ch k2, Ch k3, Ch k4) in the description of FIG. 11a can be replaced with the channels for local retransmission (Ch k5, Ch k6, Ch k4) of FIG. 11b. It can be replaced with k7, Ch k8).

[0149] As previously explained, the examples of FIGS. 10a, 10b, 11a, and 11b are merely illustrative to aid in understanding the present disclosure and are not intended to limit the present disclosure. Even if the number of source devices, the number of sink devices, the number of BIS, the number of BIS sub-events, etc., in the examples of FIGS. 10a, 10b, 11a, and 11b are changed, the present disclosure can be applied in the same principle.

[0150] FIGS. 12a through 12c illustrate an example in which the proposed method of the present disclosure is applied to a broadcast stream group according to one embodiment of the present disclosure. In contrast to the example of FIGS. 10a, 10b, 11a, and 11b, FIGS. 12a through 12c illustrate an example in which the number of sink devices receiving the first broadcast stream is expanded to any N, the number of sink devices receiving the second broadcast stream is expanded to any M, and the number of BIS sub-events is expanded to three or more. FIGS. 12a through 12c are merely examples to aid in understanding the present disclosure, and the present disclosure is not limited to the examples of FIGS. 12a through 12c. Although the examples of FIGS. 12a through 12c are described assuming an interleaved BIG, the proposed method of the present disclosure can be applied in the same way to sequentially arranged BIGs. As an example that does not limit the present disclosure, the source device (0-a) may be the source device (0-a) of FIG. 9, the sink device (1-1, 1-2, ..., 1-N) may be the sink device (1-1, 1-2, ..., 1-N) of FIG. 9, and the sink device (2-1, 2-2, ..., 2-M) may be the sink device (2-1, 2-2, ..., 2-M) of FIG. 9.

[0151] Referring to FIG. 12a, assume that a device (0-a) broadcasts two broadcast streams (e.g., BIS1, BIS2) in an interleaved manner, N devices (1-1, 1-2, ..., 1-N) receive the first broadcast stream (e.g., BIS1), and M devices (2-1, 2-2, ..., 2-M) receive the second broadcast stream (e.g., BIS2) (N, M are natural numbers greater than or equal to 1). The device (0-a) can transmit the first data (1211), second data (1213), and third data (1215) of BIS1 in BIS1 sub-event 1, BIS1 sub-event 2, and BIS2 sub-event 3, respectively, and transmit the first data (1212), second data (1214), and third data (1216) of BIS2 in BIS2 sub-event 1, BIS2 sub-event 2, and BIS2 sub-event 3, respectively. The device (0-a) can perform channel hopping on a sub-event basis to transmit the data of BIS1 (1211, 1213, 1215) and the data of BIS2 (1212, 1214, 1216) through different channels (Ch n1, Ch n2, Ch n3, Ch n4, Ch n5, Ch n6). For example, the device (0-a) can perform channel hopping based on a channel selection algorithm (e.g., channel selection algorithm #2) (e.g., see "B. Channel and Channel Hopping" of the present disclosure).

[0152] Referring to FIG. 12a, it is assumed that the device (1-1) did not successfully receive the first data (1211) of BIS1 in BIS1 sub-event 1. Accordingly, the device (1-1) can transmit a local NACK (1221) through a channel (Ch n1) for BIS1 sub-event 1 (or the first data of BIS1) (1211) in a time interval (1202) related to BIS2 (corresponding to BIS1 sub-event 1) according to the proposed method of the present disclosure. As previously described, the local NACK (1221) according to the proposed method of the present disclosure can be transmitted using an energy detection method (e.g., see FIG. 10a and related description), but other methods may be used, such as a method of transmitting NACK information by including it in a specific packet format for the transmission of the local NACK.

[0153] Since the device (1-2, 1-N) has successfully received the first data (1211) of the first broadcast stream in BIS1 sub-event 1, it can detect a local NACK through the channel (Ch n1) in the time interval (1202) associated with BIS2 (corresponding to BIS1 sub-event 1), and if a local NACK (1221) is detected, it can perform channel hopping in the time interval (1202) and then perform local retransmission (1231) of the first data (1211) of BIS1 through the channel (Ch k1).

[0154] In the proposed method of the present disclosure, local retransmission may be performed using random backoff-based contention. For example, a device (1-2, 1-N) that detects a local NACK may backoff for a random time within a maximum random backoff time period or contention window, and then check whether the channel is in use; if the channel is not in use, it may perform local retransmission, and if the channel is in use, it may repeat the random backoff until it is confirmed that the channel is not in use. If the time of local retransmission is outside the maximum random backoff time or contention window, or if the number of local retransmissions exceeds the maximum random backoff time, the device (1-2, 1-N) may be configured not to perform local retransmission. And / or, the device (1-2, 1-N) may be configured to perform local retransmission after the maximum random backoff time or contention window, regardless of the detection of a local NACK or when a local NACK is detected. In the example of FIG. 12a, devices (1-2, 1-N) may perform a local retransmission (1231) and devices (1-N) may not perform a local retransmission (1232) through random backoff (1241, 1242) based competition.

[0155] For example, a channel (Ch k1) for local retransmission can be calculated through a new channel selection algorithm associated with the transmission channel of BIS1. For example, the new channel selection algorithm may include applying a hop increasement from a channel (Ch n1) for BIS1 sub-event 1 (or the first data of BIS1) (1211). For example, the index (k1) of the channel for local retransmission (1231) can be determined based on the index (n1) of the channel for BIS1 sub-event 1 (or the first data of BIS1) (1211) and a value (n1+d) obtained by adding a predetermined hop increase value (d). If the value of n1+d exceeds the maximum value of the channel index (e.g., 36), it can be wrapped around using a modulo operation (e.g., modulo 37).

[0156] Referring again to FIG. 12a, since the device (1-N) did not successfully receive the second data (1213) of BIS1 in BIS1 sub-event 2, it may transmit a local NACK (1222) through the channel (Ch n3) in the time interval (1204) associated with BIS2 (corresponding to BIS1 sub-event 2) according to the method proposed in the present disclosure. As previously described, the local NACK (1222) may be transmitted by an energy detection method (e.g., see FIG. 10a and related description), but other methods may be used.

[0157] Since the device (1-1, 1-2) has successfully received the second data (1213) of BIS1 in BIS1 sub-event 2, it can perform detection of a local NACK through the channel (Ch n3) in the time interval (1204) related to BIS2 (corresponding to BIS1 sub-event 2), and if a local NACK (1222) is detected, it can perform channel hopping and then perform local retransmission (1233) of the second data (1213) of BIS1 using random backoff (1244) based competition through the channel (Ch k3). In the example of FIG. 12a, the device (1-1) may perform local retransmission (1233) using random backoff based competition, and the device (1-2) may not perform local retransmission (1234). As previously explained, the channel for local retransmission (Ch k3) and the channel for BIS2 sub-event 2 (Ch n4) can be determined as different channels, for example, the channel for local retransmission (Ch k4) can be calculated through a new channel selection algorithm related to the transmission channel of BIS1 (e.g., hop increment from the channel for BIS1 sub-event 2 (or second data of BIS1) (1213)). As a more specific example, the index (k3) of the channel for local retransmission (1233, 1234) can be determined based on the index (n3) of the channel for BIS1 sub-event 2 (or second data of BIS1) (1213) and a fixed hop increment value (d) (n3+d). If the value of n3+d exceeds the maximum channel index value (e.g., 36), it can be wrapped around using modulo operation (e.g., modulo 37).

[0158] In the proposed method of the present disclosure, additional local retransmission may be performed regardless of or upon detection of a local NACK (1222) after a maximum random backoff time or a contention window.

[0159] Referring again to FIG. 12a, unlike BIS1 sub-event 1 and BIS1 sub-event 2, multiple devices (1-1, 1-2) may not receive the third data (1215) of BIS1 in BIS1 sub-event 3. Even in this case, the proposed method of the present disclosure can be applied in the same way. For example, since the devices (1-1, 1-2) did not successfully receive the third data (1215) of BIS1 in BIS1 sub-event 3, they may transmit local NACKs (1223, 1224) through the respective channel (Ch n5) in the time interval (1206) associated with BIS2 (corresponding to BIS1 sub-event 3) according to the proposed method of the present disclosure. As previously described, the local NACKs (1223, 1224) may be transmitted using an energy detection method (e.g., see FIG. 10a and related description), but other methods may also be used. Local NACKs (1223, 1224) can be transmitted via a channel (Ch n5) for BIS1 sub-event 3 (or third data of BIS1) (1215), and local retransmission (1235) for the third data of BIS1 (1215) can be performed in a time interval (1206) via a channel (Ch k5) after channel hopping. The channel (Ch k5) for local retransmission can be calculated through a new channel selection algorithm related to the transmission channel of BIS1 (e.g., increasing the hop from the channel (Ch n5) for BIS1 sub-event 3 (or third data of BIS1) (1215), and if the calculated channel exceeds the maximum value of the channel index (e.g., 36), it can be wrapped around using a modulo operation (e.g., modulo 37).

[0160] In the proposed method of the present disclosure, additional local retransmission may be performed regardless of the detection of a local NACK (1223, 1224) after a maximum random backoff time or a contention window, or when a local NACK (1223, 1224) is detected.

[0161] Referring to FIG. 12b, since the device (2-M) did not successfully receive the first data (1212) of BIS2 in BIS2 sub-event 1, it may transmit a local NACK (1225) in a time interval (1203) associated with BIS1 (corresponding to BIS2 sub-event 1) according to the method proposed in the present disclosure. In an example that is not limiting to the present disclosure, the local NACK (1225) may be transmitted via an energy detection method (e.g., see FIG. 10a and related description) and may be transmitted through a channel (Ch n2) in the time interval (1203).

[0162] Since the device (2-1, 2-2) has successfully received the first data (1212) of BIS2 in BIS2 sub-event 1, it can detect a local NACK through the channel (Ch n2) in the time interval (1203) associated with BIS1, and if a local NACK (1225) is detected, it can perform channel hopping and then perform a local retransmission (1237) of the first data (1212) of BIS2 through the channel (Ch k2) in the time interval (1203). According to the method proposed in the present disclosure, the local retransmission (1237) can be performed using random backoff (1246, 1247) based competition. In the example of FIG. 12b, using random backoff (1246, 1247) based competition, device (2-2) may perform local retransmission (1237) and device (2-1) may not perform local retransmission (1236).

[0163] As previously explained, the channel for local retransmission (Ch k2) and the channel for BIS1 sub-event 2 (Ch n3) can be determined as different channels, for example, the channel for local retransmission (Ch k2) can be calculated through a new channel selection algorithm related to the transmission channel of BIS2 (e.g., hop increment from the channel for BIS2 sub-event 1 (or the first data of BIS2) (1212). As a more specific example, the index (k2) of the channel for local retransmission (1236, 1237) can be determined based on the index (n2) of the channel for BIS2 sub-event 1 (or the first data of BIS2) (1212) and a fixed hop increment value (d) (n2+d). If the value of n2+d exceeds the maximum channel index value (e.g., 36), it can be wrapped around using modulo operation (e.g., modulo 37).

[0164] In the proposed method of the present disclosure, additional local retransmission may be performed regardless of or upon detection of a local NACK (1225) after a maximum random backoff time or a contention window.

[0165] Referring again to FIG. 12b, since the device (2-1) did not successfully receive the second data (1214) of BIS2 in BIS2 sub-event 2, it may transmit a local NACK (1226) in a time interval (1205) associated with BIS1 (corresponding to BIS2 sub-event 2) according to the method proposed in the present disclosure. As previously described, the local NACK (1226) may be transmitted via an energy detection method (e.g., see FIG. 10a and related description) and may be transmitted through a channel (Ch n4) for BIS2 sub-event 2 (or the second data of BIS2) (1214).

[0166] Since the device (2-2, 2-M) has successfully received the second data (1214) of BIS2 in BIS2 sub-event 2, it can perform detection of a local NACK through the channel (Ch n4) in the time interval (1205) related to BIS1 (corresponding to BIS2 sub-event 2), and if a local NACK (1226) is detected, it can perform channel hopping and then perform local retransmission (1238) of the second data (1214) of BIS2 through the channel (Ch k4) in the time interval (1205). According to the proposed method of the present disclosure, the device (2-2) may perform local retransmission (1238) using random backoff (1248) based competition in the time interval (1205), and the device (2-M) may not perform local retransmission (1239).

[0167] As previously explained, the channel for local retransmission (Ch k4) and the channel for BIS1 sub-event 3 (Ch n5) can be determined as different channels, for example, the channel for local retransmission (Ch k5) can be calculated through a new channel selection algorithm related to the transmission channel of BIS2 (e.g., a hop increase from the channel for BIS2 sub-event 2 (or second data of BIS2) (1214)). As a more specific example, the index (k4) of the channel for local retransmission (1238, 1239) can be determined based on the index (n4) of the channel for BIS2 sub-event 2 (or second data of BIS2) (1214) and a predetermined hop increase value (d) (n4+d). If the value of n4+d exceeds the maximum channel index value (e.g., 36), it can be wrapped around using modulo operation (e.g., modulo 37).

[0168] In the proposed method of the present disclosure, additional local retransmission may be performed regardless of or upon detection of a local NACK (1226) after a maximum random backoff time or a contention window.

[0169] Referring again to FIG. 12b, unlike BIS2 sub-event 1 and BIS2 sub-event 2, multiple devices (2-1, 2-M) may not receive the third data (1216) of BIS2 in BIS2 sub-event 3. Even in this case, the proposed method of the present disclosure can be applied in the same way. For example, since the devices (2-1, 2-M) did not successfully receive the third data (1216) of BIS2 in BIS2 sub-event 3, they may each transmit local NACKs (1227, 1228) in the time interval (1207) associated with BIS1 (corresponding to BIS2 sub-event 3) according to the proposed method of the present disclosure. As previously described, the local NACKs (1227, 1228) may be transmitted using an energy detection method (e.g., see FIG. 10a and related description), but other methods may also be used. Local NACKs (1227, 1228) can be transmitted via a channel (Ch n6) for BIS2 sub-event 3 (or third data of BIS2) (1216), and local retransmission (123a) for the third data of BIS2 (1216) can be performed in a time interval (1207) via a channel (Ch k6) after channel hopping. The channel (Ch k6) for local retransmission can be calculated through a new channel selection algorithm related to the transmission channel of BIS2 (e.g., increasing the hop from the channel for BIS2 sub-event 3 (or third data of BIS2) (1216), and if the calculated channel exceeds the maximum value of the channel index (e.g., 36), it can be wrapped around using a modulo operation (e.g., modulo 37).

[0170] In the proposed method of the present disclosure, additional local retransmission may be performed regardless of or upon detection of a local NACK (1227, 1228) after a maximum random backoff time or a contention window.

[0171] Referring to FIG. 12c, the operation of the device (1-1, 1-2, ..., 1-N) exemplified in FIG. 12a and the operation of the device (2-1, 2-2, ..., 2-M) exemplified in FIG. 12b are illustrated together. As can be seen in FIG. 12, according to the proposed method of the present disclosure, data of a broadcast stream (e.g., BIS1 or BIS2) that was not successfully received can be retransmitted between receivers (e.g., device (1-1, 1-2, ..., 1-N) or device (2-1, 2-2, ..., 2-M)) using the time interval during which another broadcast stream (e.g., BIS2 or BIS1) is transmitted. Therefore, the proposed method of the present disclosure does not require changing the operation of the transmitter (0-a) and does not affect the operation of the transmitter (0-a). According to the proposed method of the present disclosure, technical effects can be expected to effectively improve the low PDR and low quality of broadcast-based transmissions in which ACK is not used through retransmission between receivers receiving a broadcast stream without changing or affecting the operation of the transmitter.

[0172] Furthermore, according to the method proposed in the present disclosure, since local NACK and local retransmission between receivers are utilized, there is no need to introduce ACK into broadcast-based transmission, nor is there a need to increase the number of unconditional retransmissions (performed without ACK) on the transmitter side. Rather, according to the method proposed in the present disclosure, since unreceived packets can be exchanged using local NACK and retransmission between receivers, a technical effect of reducing the number of unconditional retransmissions on the transmitter side can be expected. In addition, according to the method proposed in the present disclosure, since the number of unconditional retransmissions on the transmitter side can be maintained or reduced, a technical effect of maintaining or increasing the number of broadcast streams that can be transmitted within a given time resource can be expected.

[0173] Furthermore, according to the method proposed in the present disclosure, since local retransmission is performed between receivers, a receiver outside the transmitter's coverage can also receive data from a receiver within the transmitter's coverage through local retransmission between a receiver outside the transmitter's coverage and a receiver within the transmitter's coverage. Therefore, according to the method proposed in the present disclosure, a technical effect of expanding the transmitter's coverage can also be expected.

[0174] FIG. 13 illustrates a flowchart of the proposed method of the present disclosure. The flowchart of FIG. 13 is an example of the proposed method of the present disclosure, and the present disclosure is not limited to FIG. 13. Some of the operations shown in FIG. 13 may be omitted, some of the operations shown in FIG. 13 may be replaced with other operations, and operations not shown in FIG. 13 may be added. Additionally, the order of the operations shown in FIG. 13 may be changed.

[0175] The method of FIG. 13 can be performed by an electronic device. For example, the electronic device in the example of FIG. 1a and FIG. 1b is Auracast TM It may be one of the receivers, or one of the sink devices (1-1, 1-2, ..., 1-N) or sink devices (2-1, 2-2, ..., 2-M) in the example of FIG. 9 or FIG. 12a to 12c, or one of the sink devices (1-a, 1-b, 2-a, 2-b) in the example of FIG. 10a, 10b, FIG. 11a, and 11b. The proposed method of the present disclosure is Auracast TM Alternatively, since it can be applied to communication technologies other than BLE technology, electronic devices use Auracast TM Or it could be a device that supports communication technologies other than BLE technology.

[0176] Referring to FIG. 13, an electronic device can perform a BIS connection (1302). For example, the electronic device can acquire BIG information (e.g., BIGInfo field) and information for synchronizing with the currently ongoing BIS using the BIS establishment procedure described with reference to FIG. 4. Alternatively, in the 1302 operation, a method other than the BIS establishment procedure described with reference to FIG. 4 may be used. The electronic device may be in a low-power mode (or sleep mode) and periodically wake up based on the BIG information (e.g., BIGInfo field) to synchronize with the BIS and receive the BIS (1304). Alternatively, the low-power mode may not be used in the 1304 operation, in which case the periodic wake-up operation may not be performed. In the proposed method of the present disclosure, the 1302 operation and the 1304 operation may be omitted.

[0177] Referring to FIG. 13, the electronic device identifies a first time interval associated with the first broadcast stream and a second time interval associated with the second broadcast stream based on information regarding a group of broadcast streams including a first broadcast stream and a second broadcast stream, and can receive first data associated with the first broadcast stream in the first time interval associated with the first broadcast stream (1306). In an example that does not limit the present disclosure, the first broadcast stream may be an English broadcast stream (or a Spanish broadcast stream) in the example of FIG. 9 and may be BIS1 (or BIS2) in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to FIG. 12c, and the second broadcast stream may be a Spanish broadcast stream (or an English broadcast stream) in the example of FIG. 9 and may be BIS2 (or BIS1) in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to FIG. 12c. In an example that does not limit the present disclosure, the broadcast stream group may be BIG, and information regarding the broadcast stream group may be BIG information (e.g., BIGInfo field).In an example that does not limit the present disclosure, the first time interval is a sub-event of BIS1 (1011, 1012, 1015, 1016, 1111, 1113, 1115, 1117, 1211, 1213, 1215) in the examples of FIG. 10a, 10b, FIG. 11a, 11b, FIG. 12a to 12c, or a time interval including a sub-event of BIS1 (1001, 1002, 1007, 1008, 1101, 1103, 1106, 1108, 1201, 1203, 1205) (or a sub-event of BIS2 (1013, 1014, 1017, 1018, 1112, 1114, The second time interval may be a time interval (1003, 1004, 1009, 100a, 1102, 1104, 1107, 1109, 1202, 1204, 1206) including sub-events of BIS2, or a time interval including sub-events of BIS2, and the second time interval may be a time interval (1003, 1004, 1009, 100a, 1102, 1104, 1107, 1109, 1202, 1204, 1206) related to BIS2 or corresponding to sub-events of BIS1 in the examples of FIG. 10a, 10b, FIG. 11a, 11b, FIG. 12a to 12c) (or related to BIS1 or It may be a time interval corresponding to the sub-events of BIS2 (1005, 1006, 100b, 100c, 1103, 1105, 1108, 110a, 1203, 1205, 1207).

[0178] Referring to FIG. 13, if the first data associated with the first broadcast stream is not successfully received (e.g., due to a CRC error, MIC error, etc.) in the first time interval associated with the first broadcast stream (1306), the electronic device transmits a first NACK (negative acknowledgment) signal in the second time interval associated with the second broadcast stream, and in response to the first NACK signal, can receive the first data associated with the first broadcast stream in the second time interval associated with the second broadcast stream (1308). In operation 1308, for example, the first NACK signal may be a local NACK according to the proposed method of the present disclosure (e.g., 1021 to 1028 in FIG. 10a and 10b, 1121 to 1128 in FIG. 11a and 11b, 1221 to 1228 in FIG. 12a to 12c), and the first data associated with the first broadcast stream in the second time interval associated with the second broadcast stream may be a local retransmission according to the proposed method of the present disclosure (e.g., 1031 to 1038 in FIG. 10a and 10b, 1131 to 1138 in FIG. 11a and 11b, 1231, 1233, 1235, 1237, 1238, 123a in FIG. 12 to 12c).

[0179] For example, in operation 1308, the first channel for the first data (or local retransmission) associated with the first broadcast stream in the second time interval associated with the second broadcast stream and the second channel for the first data associated with the second broadcast stream in the second time interval associated with the second broadcast stream may be different. For example, as described in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a through FIG. 12c, the first channel for the first data (or local retransmission) associated with the first broadcast stream in the second time interval associated with the second broadcast stream may be calculated through a new channel selection algorithm associated with the channel for the first data associated with the first broadcast stream in the first time interval. For example, the index of the first channel for the first data (or local retransmission) associated with the first broadcast stream in the second time interval associated with the second broadcast stream (e.g., k1 to k8 in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to 12c) can be determined based on the value obtained by adding the channel index for the first data associated with the first broadcast stream in the first time interval (e.g., n1 to n8 in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to 12c) and the hop increment value (e.g., d in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to 12c). If the sum of the hop increment values ​​exceeds the maximum channel index value (e.g., 36), it can be wrapped around using modulo operation (e.g., modulo 37).

[0180] The first NACK signal may be transmitted in the second time interval associated with the second broadcast stream through the channel used for receiving the first data associated with the first broadcast stream in the first time interval associated with the first broadcast stream. In an example that does not limit the present disclosure, if the first time interval is BIS1 sub-event 1 (1011) or time interval (1001) of FIG. 10a and the second time interval is time interval (1003) of FIG. 10a, the first NACK signal (1021) may be transmitted in the second time interval (1003) through the channel (Ch n1) for the first time interval. In an example that does not limit the present disclosure, if the first time interval is BIS1 event 1 (1111) or time interval (1101) of FIG. 11a and the second time interval is time interval (1102) of FIG. 11a, the first NACK signal (1121) may be transmitted in the second time interval (1102) through the channel (Ch n1) for the first time interval. In an example that does not limit the present disclosure, if the first time interval is BIS1 sub-event 1 (1211) or time interval (1201) of FIG. 12a and the second time interval is time interval (1202) of FIG. 12a, the first NACK signal (1221) may be transmitted in the second time interval (1202) through the channel (Ch n1) for the first time interval.

[0181] The first NACK signal (or local NACK) may be transmitted using an energy detection method (e.g., see FIG. 10a and related description). Another sink device (or receiver) may determine that it has received or detected the NACK if it detects the energy of the signal through a specific channel during a specific time interval, and may determine that it has not received or detected the NACK if it does not detect the energy of the signal. The energy detection method is not the only method that can be used for the transmission of the first NACK signal, and other methods may be used, such as a method of transmitting the NACK information by including it in a specific packet format.

[0182] Referring to FIG. 13, if the first data associated with the first broadcast stream is successfully received in the first time interval associated with the first broadcast stream (1306), the electronic device may wait for the reception of a second NACK signal in the second time interval associated with the second broadcast stream (or may perform detection of the second NACK signal) (1310). If the second NACK signal is received (or the second NACK signal is detected) (1312) in the second time interval associated with the second broadcast stream, the electronic device may transmit the first data associated with the first broadcast stream in the second time interval associated with the second broadcast stream (1314). If the second NACK signal is not received (or the second NACK signal is not detected) (1312) in the second time interval associated with the second broadcast stream, the device may remain in a low-power mode until the next data is transmitted and then perform a periodic wake-up (1304). For example, the second NACK signal may be a local NACK according to the method proposed in the present disclosure (e.g., 1021 to 1028 in FIG. 10a and 10b, 1121 to 1128 in FIG. 11a and 11b, 1221 to 1228 in FIG. 12a to 12c), and the first data associated with the first broadcast stream in the second time interval associated with the second broadcast stream may be a local retransmission according to the method proposed in the present disclosure (e.g., 1031 to 1038 in FIG. 10a and 10b, 1131 to 1138 in FIG. 11a and 11b, 1231, 1233, 1235, 1237, 1238, 123a in FIG. 12 to 12c).

[0183] In the second time interval associated with the second broadcast stream, the first data (or local retransmission) (1314) associated with the first broadcast stream may be transmitted using random backoff-based contention. For example, an electronic device that detects the second NACK signal may backoff for a random time within the maximum random backoff time period or contention window, and then check whether the channel is in use; if the channel is not in use, it may perform local retransmission, and if the channel is in use, it may repeat the random backoff until it is confirmed that the channel is not in use. If the time of local retransmission is outside the maximum random backoff time or contention window, or if the number of local retransmissions exceeds the maximum random backoff time, the electronic device may be configured not to perform local retransmission. And / or, the electronic device may be configured to perform local retransmission after the maximum random backoff time or contention window regardless of the detection of the second NACK signal, or if the second NACK signal is detected.

[0184] When the electronic device receives or detects a second NACK signal (1312), the electronic device may perform channel hopping to transmit first data related to the first broadcast stream in a second time interval related to the second broadcast stream (1314). For example, channel hopping may be performed in the same manner as described in operation 1308. For example, the first channel for first data (or local retransmission) related to the first broadcast stream in a second time interval related to the second broadcast stream and the second channel for first data related to the second broadcast stream in a second time interval related to the second broadcast stream may be different. For example, as described in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to FIG. 12c, the first channel for the first data (or local retransmission) associated with the first broadcast stream in the second time interval associated with the second broadcast stream can be calculated through a new channel selection algorithm associated with the channel for the first data associated with the first broadcast stream in the first time interval. For example, the index of the first channel for the first data (or local retransmission) associated with the first broadcast stream in the second time interval associated with the second broadcast stream (e.g., k1 to k8 in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to 12c) can be determined based on the value obtained by adding the channel index for the first data associated with the first broadcast stream in the first time interval (e.g., n1 to n8 in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to 12c) and the hop increment value (e.g., d in the examples of FIG. 10a, FIG. 10b, FIG. 11a, FIG. 11b, FIG. 12a to 12c).If the sum of the hop increment values ​​exceeds the maximum channel index value (e.g., 36), it can be wrapped around using modulo operation (e.g., modulo 37).

[0185] To support local NACK and local retransmission according to the method proposed in the present disclosure, the time interval between events for a broadcast stream group may be set to be sufficiently long. For example, if an event for a broadcast stream group does not include a control sub-event (e.g., BIG event x of FIG. 10a and FIG. 11a), the time interval (e.g., ISO_Interval) from the start time of an event for a broadcast stream group (e.g., BIG event x) to the start time of the next event for a broadcast stream group (e.g., BIG event x+1) may be set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing. For example, if an event for a broadcast stream group includes a control sub-event (e.g., BIG event x+1 in FIG. 10b and FIG. 11b), the time offset (e.g., BIG_Control_Offset) from the start time of the event for the broadcast stream group (e.g., BIG event x+1) to the start time of the control sub-event can be set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing. Num_BIS represents the number of broadcast streams within the broadcast stream group, BIS_Spacing represents the time interval between the start time of a sub-event of the first broadcast stream in the broadcast stream group and the start time of a sub-event of the second broadcast stream corresponding to the sub-event of the first broadcast stream, Sub_Interval represents the time interval between the start times of two consecutive sub-events of a single broadcast stream, and max(A,B) can represent the larger value between A and B.

[0186] As illustrated in FIGS. 10a, 10b, FIGS. 11a, 11b, and FIGS. 12a through 12c, the proposed method of the present disclosure may be applied without limitation when the first broadcast stream and the second broadcast stream are received based on at least one of a sequential method or an interleaved method.

[0187] F. Structure of the device

[0188] FIG. 14 illustrates the structure of a device (1400) in which the proposed method of the present disclosure can be implemented.

[0189] Referring to FIG. 14, the device (1400) may include a processor (1410), a transceiver (1420) including a receiver and / or a transmitter, and a memory (1430). The processor (1410), the transceiver (1420), and the memory (1430) may be operably coupled and configured to implement the proposed method of the present disclosure. The structure illustrated in FIG. 14 is one example, and the device capable of implementing the proposed method of the present disclosure may be configured in various structures. For example, the device may include more or fewer components than the components illustrated in FIG. 14. In addition, at least one of the processor (1410), the transceiver (1420), and the memory (1430) may be implemented in the form of a single chip.

[0190] The transceiver (1420) may be configured to transmit and receive signals with other devices. The signals may include, for example, packets carrying data and / or control information. To this end, the transceiver (1420) may be composed of an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, and an RF receiver that low-noise amplifies the received signal and down-converts the frequency. This is an example of the transceiver (1420), and the components of the transceiver (1420) are not limited to the RF transmitter and the RF receiver.

[0191] Additionally, the transceiver (1420) can receive a signal through a wireless channel and output it to the processor (1410), and transmit the signal output from the processor (1410) through the wireless channel.

[0192] The memory (1430) can store programs and data necessary for the operation of the device (1400). Additionally, the memory (1430) can store control information or data included in signals transmitted and / or received by the device (1400). The memory (1430) may be composed of a storage medium or a combination of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memories.

[0193] A processor (1410) can control a series of processes to enable the device (1400) to operate according to the proposed method of the present disclosure. For example, the processor (1410) can control each component of the device (1400) to configure and transmit a CE trigger packet, a CE signal, and / or a channel report packet. There may be multiple processors (1410), and a processor (14610) can perform component control operations of the device (1400) by executing a program stored in memory (1430).

[0194] The methods described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0195] When implemented in software, a non-transient computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the non-transient computer-readable storage medium are configured for execution by one or more processors within the device. One or more programs include instructions that cause the device to execute the claims of the present disclosure or the proposed methods of the present disclosure.

[0196] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), magnetic disc storage devices, CD-ROM (Compact Disc-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0197] Additionally, the program may be stored on an attachable storage device accessible via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to a device performing the proposed method of the present disclosure through an external port. Additionally, a separate storage device on the communication network may be connected to a device performing the proposed method of the present disclosure.

[0198] In the proposed method of the present disclosure described above, the components included in the invention are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, or even if a component is expressed in the singular form, it may be composed of a plural form.

[0199] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments may be combined and operated as needed. For example, a device may be operated by combining parts of one embodiment of the present disclosure with parts of another embodiment. Although the above embodiments are presented based on a Bluetooth® LE system, other variations based on the technical concept of the above embodiments may be implemented in other systems, such as other Bluetooth® systems developed in the future.

[0200] Meanwhile, the order of description in the drawings illustrating the method of the present invention does not necessarily correspond to the order of execution, and the order of execution may be changed or executed in parallel.

[0201] Alternatively, drawings describing the method of the present invention may omit some components and include only some components to the extent that the essence of the present invention is not compromised.

[0202] In addition, the method of the present invention may be implemented by combining some or all of the contents included in each embodiment to the extent that it does not impair the essence of the invention.

[0203] Various embodiments of the present disclosure have been described above. The foregoing description of the present disclosure is for illustrative purposes only and is not limited to the embodiments disclosed. Those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present disclosure. The scope of the present disclosure is defined by the claims set forth below rather than by the foregoing detailed description, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included within the scope of the present disclosure.

Claims

1. In a method performed by an electronic device in a wireless communication system, A step of identifying a first time interval associated with the first broadcast stream and a second time interval associated with the second broadcast stream based on information regarding a broadcast stream group including a first broadcast stream and a second broadcast stream; If the first data associated with the first broadcast stream is not successfully received during the first time interval associated with the first broadcast stream, A step of transmitting a first NACK (negative acknowledgment) signal in a second time interval associated with the second broadcast stream; and A method comprising the step of receiving first data associated with the first broadcast stream in a second time interval associated with the second broadcast stream in response to the first NACK signal.

2. In Claim 1, If the first data associated with the first broadcast stream is successfully received during the first time interval associated with the first broadcast stream, A step of detecting a second NACK signal in a second time interval associated with the second broadcast stream; and A method further comprising the step of transmitting first data associated with the first broadcast stream in the second time interval associated with the second broadcast stream when the second NACK signal is detected in the second time interval associated with the second broadcast stream.

3. In Claim 2, The step of transmitting the first data associated with the first broadcast stream in the second time interval associated with the second broadcast stream is A method comprising transmitting first data associated with the first broadcast stream through random backoff-based competition in the second time interval.

4. In Claim 2, A method in which, when the second NACK signal is detected in the second time interval associated with the second broadcast stream, the first data associated with the first broadcast stream is not transmitted through random backoff-based competition in the second time interval associated with the second broadcast stream.

5. In Claim 1, A method further comprising the step of transmitting the first data associated with the first broadcast stream after a maximum random backoff time in a second time interval associated with the second broadcast stream when the first data associated with the first broadcast stream is successfully received in a first time interval associated with the first broadcast stream.

6. In Claim 1, A method in which the first channel for the first data associated with the first broadcast stream in the second time interval associated with the second broadcast stream and the second channel for the first data associated with the second broadcast stream in the second time interval associated with the second broadcast stream are different from each other.

7. In Claim 5, A method in which the index of the first channel is determined based on the value obtained by adding the channel index for the first data associated with the first broadcast stream and the hop increase value in the first time interval associated with the first broadcast stream.

8. In Claim 1, A method in which the first NACK signal is transmitted in a second time interval associated with the second broadcast stream through a channel used for receiving the first data associated with the first broadcast stream in a first time interval associated with the first broadcast stream.

9. In Claim 1, The above first NACK signal is transmitted based on an energy detection method.

10. In Claim 1, If the event for the broadcast stream group does not include a control sub-event, the time interval from the start time of the event for the broadcast stream group to the start time of the next event for the broadcast stream group is set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing, and Num_BIS represents the number of broadcast streams within the broadcast stream group, BIS_Spacing represents the time interval between the start time of a sub-event of the first broadcast stream and the start time of a sub-event of the second broadcast stream corresponding to the sub-event of the first broadcast stream in the broadcast stream group, Sub_Interval represents the time interval between the start times of two consecutive sub-events of a single broadcast stream, and max(A,B) represents the larger value between A and B, method.

11. In Claim 1, If the event for the broadcast stream group includes a control sub-event, the time offset from the start time of the event for the broadcast stream group to the start time of the control sub-event is set to be greater than or equal to Num_BIS * max(BIS_Spacing, Sub_Interval) + BIS_Spacing, and Num_BIS represents the number of broadcast streams within the broadcast stream group, BIS_Spacing represents the time interval between the start time of a sub-event of the first broadcast stream and the start time of a sub-event of the second broadcast stream corresponding to the sub-event of the first broadcast stream in the broadcast stream group, Sub_Interval represents the time interval between the start times of two consecutive sub-events of a single broadcast stream, and max(A,B) represents the larger value between A and B, method.

12. In Claim 1, A method in which the first broadcast stream and the second broadcast stream are received based on at least one of a sequential method or an interleaved method.

13. In Claim 1, Each of the first broadcast stream and the second broadcast stream comprises a broadcast isochronous stream (BIS), and The above broadcast stream group includes a broadcast isochronous group (BIG), and The information regarding the above broadcast stream group includes BIG information, and A method in which each of the first time interval and the second time interval includes a BIS sub-event.

14. In an electronic device in a wireless communication system, transceiver; and At least one processor connected to the above-mentioned transceiver; and An electronic device comprising a memory comprising an instruction configured such that the electronic device implements any one of claims 1 to 13 when performed by at least one processor.

15. A non-transient computer-readable recording medium comprising an instruction configured such that, when performed by at least one processor, an electronic device including said at least one processor implements any one of the methods of claims 1 to 13.

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