Method for estimating channels and relative positions of plurality of speakers using bluetooth low energy (LE) technology and apparatus thereof

Abstract

A method for operating an electronic device in a short-range wireless communication system according to an embodiment disclosed in the present specification comprises the steps of: receiving information related to first distances between speakers; and determining relative positions of the speakers on the basis of the information. The first distances are measured on the basis of a channel sounding procedure between the speakers.

Description

Method and device for estimating channels and relative positions of multiple speakers using Bluetooth LE (LOW ENERGY) technology

[0001] The present specification relates to a method and a device for estimating channels of multiple devices using Bluetooth LE (Bluetooth Low Energy, BLE) technology, and to a method and a device for estimating channels and locations of each of multiple devices based on BLE technology and channel sounding.

[0002] Bluetooth is a short-range wireless communication technology developed to support two-way communication between various portable electronic devices, including personal digital assistants, mobile phones, laptops, and computers. Bluetooth technology primarily uses the 2.4 GHz frequency band for wireless communication, enabling data transmission with relatively low power consumption. Initially used primarily as a cable replacement, it has now expanded into diverse applications, including audio streaming, data synchronization, and device control.

[0003] BLE (Bluetooth Low Energy) is a low-power wireless communication technology that offers short-range wireless communication capabilities while consuming significantly less power than conventional Bluetooth. BLE is particularly suited for applications requiring low data rates and long battery life, such as battery-powered devices, Internet of Things (IoT) devices, and wearables.

[0004] BLE is optimized for intermittent data transmission, activating only for brief periods to transmit data before transitioning back to low-power standby mode. Furthermore, BLE maximizes energy efficiency by offering a streamlined protocol stack and faster connection setup times.

[0005] Existing Bluetooth audio connection technology was developed primarily to transmit stereo (2-channel) audio signals. It is used to wirelessly stream high-quality stereo audio from audio source devices such as smartphones, tablets, computers, and TVs to audio sink (receiving) devices such as Bluetooth earphones, headphones, and speakers.

[0006] Conventional 2-channel Bluetooth audio connections are typically based on 1:1 connections, with one audio source device transmitting stereo audio to one audio receiver device.

[0007] Meanwhile, with the increasing trend of streaming content supporting 5.1-channel surround audio or video beyond 2-channel using BLE, a method for transmitting multi-channel audio using BLE and a method for measuring the distance between devices based on Bluetooth technology are defined.

[0008] Early distance measurement methods used the Received Signal Strength Indicator (RSSI) to roughly estimate the distance between devices, based on the principle that the stronger the signal strength, the closer the devices are.

[0009] Later, distance measurement methods based on Angle of Arrival (AoA) or Angle of Departure (AoD) technology were introduced. These methods measure the angle of arrival or departure of a signal to determine the relative orientation of the device and estimate the distance based on this. However, AoA or AoD-based technologies have the limitation that they require two or more antennas for distance measurement.

[0010] In Bluetooth versions 6.0 and later, a distance measurement method based on the Channel Sounding procedure, which exploits the characteristics of the wireless channel, has been proposed. This method, based on the Channel Sounding procedure, measures distance based on signal arrival time (ToF) and phase changes. Compared to existing methods, it boasts higher accuracy and allows distance measurement with a single antenna.

[0011] Building a conventional 5.1-channel surround system involves a complex, wired installation process, requiring a physical connection from the player and receiver to each speaker. This hinders the freedom of speaker placement and ease of installation in typical environments like living rooms. In particular, compared to conventional 2.1-channel audio systems, placing multiple speakers and connecting them individually via wires poses significant spatial constraints, and the difficulty of cable management significantly reduces user convenience.

[0012] Furthermore, the existing Bluetooth 2.1 / 3.1 / EDR standards have limitations such as limited use cases for digital projection, and the large encoding delay of the audio codec makes them incapable of providing the precise synchronization required in multi-channel audio systems. This makes them unsuitable for environments such as 5.1-channel surround sound, where precise time synchronization between multiple speakers is essential. Therefore, when building a 5.1-channel surround system using wireless Bluetooth technology, there is the challenge of providing an optimal sound experience due to audio synchronization issues between each speaker.

[0013] The purpose of this specification is to overcome the limitations of these existing technologies and propose a method for building a flexible and optimized surround audio system in a wireless environment.

[0014] The technical problems to be achieved in this specification are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0015] In order to solve the above-described technical problem, a method of operating an electronic device in a short-range wireless communication system according to one embodiment of the present specification includes a step of receiving information related to first distances between speakers and a step of determining relative positions of the speakers based on the information.

[0016] The above first distances are measured based on the channel sounding procedure between the speakers.

[0017] The above relative positions can be determined based on the sum of the distances of each of the speakers to other speakers.

[0018] i) Among the above speakers, the speaker with the smallest sum of distances to other speakers is determined as the center speaker, ii) Among the above speakers, a predetermined number of speakers that are relatively close to the center speaker are determined as front speakers, and iii) Among the above speakers, the remaining speakers can be determined as rear speakers.

[0019] The front speakers may include a front left (FL) speaker and a front right (FR) speaker, and the rear speakers may include a rear left (RL) speaker and a rear right (RR) speaker.

[0020] Among the above front speakers, the FL speaker and the FR speaker can be determined based on test sound reproduction.

[0021] i) Among the rear speakers, a speaker that is relatively close to the FL speaker may be determined as the RL speaker, or ii) among the rear speakers, a speaker that is relatively close to the FR speaker may be determined as the RR speaker.

[0022] The step of determining the relative positions may include the step of measuring second distances between the electronic device and the speakers based on the channel sounding, and the step of determining the relative positions of the electronic device and the speakers based on the information and the second distances.

[0023] The method may further include a step of transmitting information related to the adjusted delay based on the second distances to each of the speakers.

[0024] The above delay can be adjusted based on the speaker that is relatively farthest from the electronic device among the speakers.

[0025] The method may further include the steps of transmitting a test audio signal to each of the speakers, measuring a sound pressure level (SPL) of each of the speakers based on the test audio played by each of the speakers, and adjusting a volume of each of the speakers based on the SPL.

[0026] Among the above speakers, the volume of other speakers can be adjusted based on the SPL of the center speaker.

[0027] In another embodiment of the present specification, a method for operating a speaker included in a plurality of speakers in a short-range wireless communication system comprises a step of measuring first distances between the speakers to determine relative positions of the speakers, and a step of transmitting information related to the first distances between the speakers to the device.

[0028] The above first distances are measured based on a channel sounding procedure between the speakers.

[0029] The above relative positions can be determined based on the sum of the distances of each of the speakers to other speakers.

[0030] i) Among the above speakers, the speaker with the smallest sum of distances to other speakers is determined as the center speaker, ii) Among the above speakers, a predetermined number of speakers that are relatively close to the center speaker are determined as front speakers, and iii) Among the above speakers, the remaining speakers can be determined as rear speakers.

[0031] The front speakers may include a front left (FL) speaker and a front right (FR) speaker, and the rear speakers may include a rear left (RL) speaker and a rear right (RR) speaker.

[0032] Among the above front speakers, the FL speaker and the FR speaker can be determined based on test sound reproduction.

[0033] i) Among the rear speakers, a speaker that is relatively close to the FL speaker may be determined as the RL speaker, or ii) among the rear speakers, a speaker that is relatively close to the FR speaker may be determined as the RR speaker.

[0034] The method may further include the step of receiving information related to an adjusted delay from the electronic device based on second distances between the electronic device and the speakers.

[0035] The above second distances can be measured based on the channel sounding.

[0036] The above delay can be adjusted based on the speaker that is relatively farthest from the electronic device among the speakers.

[0037] The method may include receiving a test audio signal from the electronic device, playing test audio based on the test audio signal, receiving an audio signal from the electronic device based on an adjusted volume, and playing audio based on the audio signal.

[0038] The above volume can be adjusted based on the SPL of the center speaker among the above speakers.

[0039] In another embodiment of the present specification, an electronic device,

[0040] A method of operating an electronic device in a short-range wireless communication system, comprising: one or more transceivers, one or more processors, and one or more memories storing instructions that, when executed by the one or more processors, perform operations, wherein the operations are:

[0041] A step of receiving information related to first distances between speakers, and

[0042] A step of determining the relative positions of the speakers based on the above information is included.

[0043] The above first distances can be measured based on a channel sounding procedure between the speakers.

[0044] According to conventional technology, there are problems of installation complexity and space constraints due to the wired connection required to build a 5.1 channel surround audio system.

[0045] According to the embodiments of the present specification, 5.1 channel speakers can be flexibly configured according to the number and type of available Bluetooth portable speakers, thereby supporting users to freely build an optimal surround system that suits them by utilizing the portable speakers they currently own, and providing a multi-channel audio experience without being restricted by a specific fixed hardware configuration.

[0046] Previous technology had difficulty identifying the exact location of each speaker and optimizing the system accordingly.

[0047] According to an embodiment of the present specification, the channel and position of a speaker can be estimated using LE Audio and Channel Sounding technology, and an optimized surround system can be configured based on the estimated channel and position.

[0048] According to the embodiment of the present specification, there is an advantage in that the optimal listening point (sweetspot) can be created through volume adjustment and delay adjustment even when the position of the speaker is not the exact surround channel position.

[0049] According to embodiments of the present specification, a user can easily build a multi-channel surround audio system in a wireless environment and overcome the limitations of physical arrangement of speakers to provide an optimized sound experience at the user's listening position.

[0050] The effects that can be obtained from this specification are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0051] The accompanying drawings are intended to aid in understanding the present disclosure and, together with detailed descriptions, may provide embodiments of the present disclosure. However, the technical features of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. Reference numerals in each drawing may indicate structural elements.

[0052] Figure 1 is a schematic diagram showing an example of a wireless communication system using the Bluetooth low energy technology proposed in this specification.

[0053] FIG. 2 shows an example of an internal block diagram of a device capable of implementing the methods proposed in this specification.

[0054] Figure 3 shows an example of a Bluetooth communication architecture to which the methods proposed in this specification can be applied.

[0055] Figure 4 shows an example of the structure of the GATT (Generic Attribute Profile) of Bluetooth low energy.

[0056] FIG. 5 is a flowchart illustrating an example of a connection procedure method in Bluetooth low energy technology to which various embodiments of the present specification can be applied.

[0057] FIG. 6 illustrates an example of a system structure in which multi-channel audio signals are transmitted between a BLE-based audio transmitting device and a plurality of BLE audio receiving devices.

[0058] Figure 7 illustrates an example of a procedure in which an audio transmitting device transmits an audio signal to multiple audio receiving devices in a unicast manner.

[0059] Figure 8 illustrates an example of a procedure in which an audio transmitting device transmits an audio signal to a plurality of audio receiving devices in a broadcast manner.

[0060] Figure 9 illustrates an example of hardware having two speakers built into an audio transmitting device.

[0061] FIG. 10 illustrates an example of a channel sounding procedure according to an embodiment of the present specification.

[0062] FIG. 11 illustrates an example of a device for receiving information related to the distance between measured speakers according to an embodiment of the present disclosure.

[0063] FIGS. 12 and 13 illustrate an example of a procedure for estimating the positions of speakers based on measured distances between speakers according to an embodiment of the present disclosure.

[0064] Figure 14 is a diagram illustrating a case where the distances between the front speakers and the rear speakers and the user are different.

[0065] Figure 15 is a diagram illustrating a case where the distances between the rear speakers and the user are different.

[0066] Figure 16 is a diagram illustrating the decreasing trend of sound pressure according to the distance from the speaker.

[0067] FIG. 17 illustrates an example of an overall procedure for adjusting the volume and delay of multiple speakers according to an embodiment of the present disclosure.

[0068] FIG. 18 illustrates an example of a volume adjustment procedure for multiple speakers according to an embodiment of the present specification.

[0069] FIG. 19 illustrates an example of a delay adjustment procedure for multiple speakers according to an embodiment of the present specification.

[0070] FIG. 20 is a flowchart illustrating a method according to one embodiment of the present specification.

[0071] FIG. 21 is a flowchart illustrating a method according to another embodiment of the present specification.

[0072] In various embodiments of the present disclosure, “A or B” may mean “only A,” “only B,” or “both A and B.” In other words, in various embodiments of the present disclosure, “A or B” may be interpreted as “A and / or B.” For example, in various embodiments of the present disclosure, “A, B or C” may mean “only A,” “only B,” “only C,” or “any combination of A, B and C.”

[0073] In various embodiments of the present disclosure, a slash ( / ) or a comma may mean "and / or." For example, "A / B" may mean "A and / or B." Accordingly, "A / B" may mean "only A," "only B," or "both A and B." For example, "A, B, C" may mean "A, B, or C."

[0074] In various embodiments of the present disclosure, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Furthermore, in various embodiments of the present disclosure, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted as equivalent to “at least one of A and B.”

[0075] Additionally, in various embodiments of the present disclosure, “at least one of A, B and C” can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.” Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C.”

[0076] Figure 1 is a schematic diagram showing an example of a wireless communication system using the Bluetooth low energy technology proposed in this specification.

[0077] A wireless communication system (100) includes at least one server device (Server Device, 120) and at least one client device (Client Device, 110).

[0078] The server device and client device perform Bluetooth communication using Bluetooth Low Energy (BLE, hereinafter referred to as 'BLE' for convenience) technology.

[0079] First, BLE technology has a relatively small duty cycle compared to Bluetooth BR / EDR (Basic Rate / Enhanced Data Rate) technology, allows for low-cost production, and significantly reduces power consumption through low-speed data transmission rates, enabling operation for more than a year using a coin cell battery.

[0080] Additionally, BLE technology simplifies the connection process between devices and is designed to have a smaller packet size compared to Bluetooth BR / EDR technology.

[0081] In BLE technology, (1) the number of RF channels is 40, (2) the data transmission speed supports 1 Mbps, (3) the topology is a scatternet structure, (4) the latency is 3 ms, (5) the maximum current is 15 mA or less, (6) the output power is 10 mW (10 dBm) or less, and (7) it is mainly used in applications such as mobile phones, watches, sports, healthcare, sensors, and device control.

[0082] The server device (120) can operate as a client device in a relationship with other devices, and the client device can operate as a server device in a relationship with other devices. That is, in a BLE communication system, any one device can operate as a server device or a client device, and, if necessary, can operate as a server device and a client device simultaneously.

[0083] The above server device (120) may be expressed as a data service device, a client device, a slave device, a server, a conductor, a host device, a gateway, a sensing device, a monitoring device, a first device, a second device, etc.

[0084] The above client device (110) can be expressed as a server device (master device), a master, a client, a member, a sensor device, a sink device, a collector, a third device, a fourth device, etc.

[0085] The server device and the client device are the main components of the wireless communication system, and the wireless communication system may include other components in addition to the server device and the client device.

[0086] The above server device refers to a device that receives data from a client device and performs direct communication with the client device, thereby providing data to the client device through a response when receiving a data request from the client device.

[0087] Additionally, the server device sends a notification message and an indication message to the client device to provide data information to the client device. Additionally, when the server device transmits an indication message to the client device, it receives a confirmation message corresponding to the indication message from the client.

[0088] In addition, the server device can provide data information to a user through an output unit (Display Unit) or receive a request input from a user through an input unit (User Input Interface) in the process of transmitting and receiving notifications, instructions, and confirmation messages to and from a client device.

[0089] Additionally, the server device can read data from a memory unit or write new data to the memory unit during the process of transmitting and receiving messages with the client device.

[0090] Additionally, one server device can be connected to multiple client devices, and can easily reconnect (or connect) to the client devices by utilizing bonding information.

[0091] The above client device (120) refers to a device that requests data information and data transmission from a server device.

[0092] The client device receives data from the server device through a notification message, an instruction message, etc., and when receiving an instruction message from the server device, sends a confirmation message in response to the instruction message.

[0093] Likewise, the client device can provide information to the user through an output unit or receive input from the user through an input unit during the process of transmitting and receiving messages with the server device.

[0094] Additionally, the client device can read data from memory or write new data to the memory during the process of transmitting and receiving messages with the server device.

[0095] Hardware components such as the output section, input section, and memory of the above server device and client device will be examined in detail in Fig. 2.

[0096] Additionally, the wireless communication system can establish a Personal Area Network (PAN) via Bluetooth technology. For example, the wireless communication system can establish a private piconet between devices, enabling the quick and secure exchange of files, documents, and other information.

[0097] FIG. 2 shows an example of an internal block diagram of a device capable of implementing the methods proposed in this specification.

[0098] As illustrated in FIG. 2, the server device (110) includes an input unit (User Input Interface, 112), a power supply unit (Power Supply Unit, 113), a control unit (Control Unit, 114), a memory unit (Memory Unit, 115), a network interface (Network Interface, 116) including a Bluetooth interface, storage (Storage, 117), an output unit (Display Unit, 118), and a multimedia module (Multi Media Module, 119).

[0099] The input unit (User Input Interface, 112), power supply unit (Power Supply Unit, 113), control unit (Control Unit, 114), memory (Memory Unit, 115), network interface (Network Interface, 116) including Bluetooth interface, storage (Storage, 117), output unit (Display Unit, 118), and multimedia module (Multi media Module, 119) are functionally interconnected to perform the method proposed in this specification.

[0100] In addition, as illustrated in FIG. 2, the client devices (#1 and #2) (120) include an input unit (User Input Interface, 122), a power supply unit (Power Supply Unit, 123), a control unit (Control Unit, 124), a memory unit (Memory Unit, 125), a network interface (Network Interface, 126) including a Bluetooth interface, storage (Storage, 127), an output unit (Display Unit, 128), and a multimedia module (Multi media Module, 129).

[0101] The above input unit (User Input Interface, 122), power supply unit (Power Supply Unit, 123), control unit (Control Unit, 124), memory (Memory Unit, 125), network interface (Network Interface, 126) including Bluetooth interface, storage (Storage, 127), output unit (Display Unit, 128), and multimedia module (Multi media Module, 129) are functionally interconnected to perform the method proposed in this specification.

[0102] The above network interface (116, 126) refers to a unit (or module) that can transmit data, such as request / response, command, notification, instruction / confirmation messages, etc., between devices using Bluetooth technology.

[0103] The above memory (115, 125) is a unit implemented in various types of devices, and refers to a unit in which various types of data are stored. In addition, the storage (117, 127) refers to a unit that performs a function similar to memory.

[0104] The above control unit (114, 124) refers to a module that controls the overall operation of the server device (110) or client device (120), and controls to request transmission of a message to a network interface or to process a received message.

[0105] The above control unit (114, 124) may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and / or a data processing device.

[0106] The above memory (115, 125) may include a ROM (read-only memory), a RAM (random access memory), a flash memory, a memory card, a storage medium, and / or other storage devices.

[0107] The above memory (115, 125) may be internal or external to the processor (114, 124) and may be connected to the processor (114, 124) by various well-known means.

[0108] The above output unit (118, 128) refers to a module for providing device status information and message exchange information to the user through a screen.

[0109] The above power supply unit (power supply unit, 113, 123) refers to a module that receives external power and internal power under the control of the control unit and supplies the power required for the operation of each component.

[0110] As discussed above, BLE technology has a small duty cycle and can significantly reduce power consumption through low data rates.

[0111] Figure 3 shows an example of a Bluetooth communication architecture to which the methods proposed in this specification can be applied.

[0112] Specifically, FIG. 3 shows an example of the architecture of Bluetooth LE (Low Energy).

[0113] As illustrated in FIG. 3, the BLE architecture includes a controller stack (Controller stackACK) operable to handle timing-critical wireless device interfaces and a host stack (Host stackACK) operable to handle high level data.

[0114] The above Controller stack may be referred to as a Controller, but to avoid confusion with the processor, which is an internal component of the device mentioned in FIG. 2 above, it will be referred to as a Controller stackACK hereinafter.

[0115] First, the controller stack may be implemented using a communication module that may include a Bluetooth radio, and a processor module that may include a processing device, such as a microprocessor.

[0116] The host stack can be implemented as part of an OS running on a processor module, or as an instantiation of a package on top of the OS.

[0117] In some cases, the controller stack and the host stack may operate or execute on the same processing device within a processor module.

[0118] The host stack includes GAP (Generic Access Profile, 310), GATT-based Profiles (320), GATT (Generic Attribute Profile, 330), ATT (Attribute Protocol, 340), SM (Security Manager, 350), and L2CAP (Logical Link Control and Adaptation Protocol, 360). However, the host stack is not limited to this and may include various protocols and profiles.

[0119] The host stack multiplexes various protocols, profiles, etc. provided above Bluetooth using L2CAP.

[0120] First, L2CAP (Logical Link Control and Adaptation Protocol,360) provides a single bidirectional channel for transmitting data to a specific protocol or profile.

[0121] L2CAP may be capable of multiplexing data between upper layer protocols, segmenting and reassembling packages, and managing multicast data transmission.

[0122] BLE uses three fixed channels (one for signaling CH, one for Security Manager, and one for Attribute protocol).

[0123] On the other hand, BR / EDR (Basic Rate / Enhanced Data Rate) uses dynamic channels and supports protocol service multiplexer, retransmission, streaming mode, etc.

[0124] SM (Security Manager, 350) is a protocol for authenticating devices and providing key distribution.

[0125] ATT (Attribute Protocol, 340) defines the rules for accessing data from other devices in a server-client architecture. ATT has six message types: Request, Response, Command, Notification, Indication, and Confirmation.

[0126] That is, ① Request and Response messages: The Request message is a message for requesting specific information from a client device to a server device, and the Response message is a response message to the Request message, and refers to a message transmitted from the server device to the client device.

[0127] ② Command message: A message sent from a client device to a server device to instruct a specific action command. The server device does not send a response to the Command message to the client device.

[0128] ③ Notification message: A message sent from a server device to a client device for notification of events, etc.; the client device does not send a confirmation message for the Notification message to the server device.

[0129] ④ Indication and Confirm messages: Messages sent from the server device to the client device for notification of events, etc. Unlike the Notification message, the client device sends a confirmation message for the Indication message to the server device.

[0130] GAP (Generic Access Profile) is a new layer implemented for BLE technology, which is used to control role selection for communication between BLE devices and how multi-profile operation occurs.

[0131] Additionally, GAP is primarily used in device discovery, connection creation, and security procedures, defines how to provide information to users, and defines the types of attributes as follows:

[0132] ① Service: Defines the basic operation of the device through a combination of data-related behaviors.

[0133] ② Include: Defines the relationship between services

[0134] ③ Characteristics: Data values ​​used in the service

[0135] ④ Behavior: Computer-readable format defined as UUID (Universal Unique Identifier, value type)

[0136] GATT-based Profiles are profiles that depend on GATT and are primarily applied to BLE devices. GATT-based Profiles include Battery, Time, FindMe, Proximity, Time, and Object Delivery Service. The specifics of GATT-based Profiles are as follows.

[0137] Battery: How to exchange battery information

[0138] Time: A method for exchanging time information

[0139] FindMe: Distance-based alarm service

[0140] Proximity: How to Exchange Battery Information

[0141] Time: A method for exchanging time information

[0142] GATT can function as a protocol that describes how ATT is used when composing services. For example, GATT can be used to specify how ATT attributes are grouped into services, and can be used to describe the features associated with services.

[0143] Therefore, GATT and ATT can use features to describe the state and services of a device, how features relate to each other, and how they are used.

[0144] The controller stack includes a physical layer (390), a link layer (380), and a host controller interface (370).

[0145] The physical layer (wireless transmission / reception module, 390) is a layer that transmits and receives 2.4 GHz wireless signals and uses GFSK (Gaussian Frequency Shift Keying) modulation and a frequency hopping technique consisting of 40 RF channels.

[0146] The link layer (380) transmits or receives Bluetooth packets.

[0147] Additionally, the link layer performs advertising and scanning functions using three advertising channels, then creates a connection between devices, and provides the ability to send and receive data packets of up to 42 bytes through 37 data channels.

[0148] HCI (Host Controller Interface) provides an interface between the Host stack and the Controller stack, allowing the Host stack to provide commands and data to the Controller stack, and allowing the Controller stack to provide events and data to the Host stack.

[0149] Below, we will briefly look at the procedures of Bluetooth Low Energy (BLE) technology.

[0150] BLE procedures can be divided into device filtering procedures, advertising procedures, scanning procedures, discovering procedures, and connecting procedures.

[0151] Device Filtering Procedure

[0152] Device filtering procedures are a way to reduce the number of devices that respond to requests, instructions, notifications, etc. in the controller stack.

[0153] When a request is received from any device, since it is unnecessary to respond to it, the controller stack can control the power consumption of the BLE controller stack by reducing the number of requests transmitted.

[0154] An advertising device or scanning device may perform the above device filtering procedure to limit the devices that receive advertising packets, scan requests, or connection requests.

[0155] Here, an advertising device refers to a device that transmits an advertising event, i.e., performs an advertisement, and is also expressed as an advertiser.

[0156] A scanning device is a device that performs scanning and transmits scan requests.

[0157] In BLE, when a scanning device receives some advertising packets from an advertising device, the scanning device must send a scan request to the advertising device.

[0158] However, if a device filtering procedure is used to make sending scan requests unnecessary, the scanning device may ignore advertising packets transmitted from the advertising device.

[0159] Device filtering procedures may also be used during the connection request process. If device filtering is used during the connection request process, the connection request is ignored, eliminating the need to send a response to the connection request.

[0160] Advertising Procedure

[0161] An advertising device performs an advertising procedure to perform a non-directional broadcast to devices within the area.

[0162] Here, non-directional broadcast refers to broadcast in all directions rather than broadcasting in a specific direction.

[0163] In contrast, a directional broadcast refers to a broadcast in a specific direction. A non-directional broadcast occurs without a connection procedure between an advertising device and a device in a listening (or listening) state (hereinafter referred to as a listening device).

[0164] The advertising process is used to establish a Bluetooth connection with a nearby initiating device.

[0165] Alternatively, the advertising procedure may be used to provide periodic broadcasts of user data to scanning devices listening on the advertising channel.

[0166] In the advertising process, all advertisements (or advertising events) are broadcast through the advertising physical channel.

[0167] Advertising devices can receive scan requests from listening devices that are listening to obtain additional user data from the advertising device. The advertising device transmits a response to the scan request to the device that sent the scan request over the same advertising physical channel as the advertising physical channel that received the scan request.

[0168] Broadcast user data sent as part of advertising packets is dynamic data, whereas scan response data is typically static data.

[0169] An advertising device can receive a connection request from an initiating device on an advertising (broadcast) physical channel. If the advertising device uses a connectable advertising event and the initiating device is not filtered by the device filtering procedure, the advertising device stops advertising and enters connected mode. The advertising device can resume advertising after entering connected mode.

[0170] Scanning Procedure

[0171] A device performing scanning, i.e., a scanning device, performs a scanning procedure to listen for non-directional broadcasts of user data from advertising devices using an advertising physical channel.

[0172] The scanning device transmits a scan request to the advertising device via the advertising physical channel to request additional data from the advertising device. The advertising device transmits a scan response, which is a response to the scan request, including the additional data requested from the scanning device via the advertising physical channel.

[0173] The above scanning procedure can be used while connecting with other BLE devices in a BLE piconet.

[0174] If the scanning device receives a broadcasted advertising event and is in initiator mode, which allows it to initiate a connection request, the scanning device can initiate a Bluetooth connection with the advertising device by transmitting a connection request to the advertising device over the advertising physical channel.

[0175] When a scanning device sends a connection request to an advertising device, the scanning device stops initiator mode scanning for further broadcasts and enters connection mode.

[0176] Discovery Procedure

[0177] Devices capable of Bluetooth communication (hereinafter referred to as “Bluetooth devices”) perform advertising and scanning procedures to discover nearby devices or to be discovered by other devices within a given area.

[0178] The discovery process is performed asymmetrically. A Bluetooth device attempting to discover other devices in its vicinity is called a discovering device and listens for devices advertising scannable advertising events. A Bluetooth device discovered and available to other devices is called a discoverable device and actively broadcasts advertising events over the advertising (broadcast) physical channel to make it scannable.

[0179] Both the discovering device and the discoverable device may already be connected to other Bluetooth devices in the piconet.

[0180] Connecting Procedure

[0181] The connection procedure is asymmetric, requiring one Bluetooth device to perform an advertising procedure while another Bluetooth device performs a scanning procedure.

[0182] That is, the advertising process can be targeted, resulting in only one device responding to the advertisement. After receiving an accessible advertising event from the advertising device, a connection can be initiated by sending a connection request to the advertising device via the advertising (broadcast) physical channel.

[0183] Next, we will briefly look at the operating states in BLE technology, namely Advertising State, Scanning State, Initiating State, and Connection State.

[0184] Advertising State

[0185] The Link Layer (LL) enters the advertising state at the direction of the host (stack). When the Link Layer is in the advertising state, it transmits advertising Packet Data Units (PDUs) in advertising events.

[0186] Each advertising event consists of at least one advertising PDU, which are transmitted via the advertising channel indices used. An advertising event may terminate when each advertising PDU has been transmitted via the advertising channel indices used, or may terminate earlier if the advertising device needs to free up space for other functions.

[0187] Scanning State

[0188] The link layer enters the scanning state at the direction of the host (stack). In the scanning state, the link layer listens for advertising channel indices.

[0189] There are two types of scanning states: passive scanning and active scanning, and each scanning type is determined by the host.

[0190] No separate time or advertising channel index is defined for performing scanning.

[0191] During the scanning state, the link layer listens for advertising channel indices for the duration of the scanWindow. The scanInterval is defined as the interval between the start points of two consecutive scan windows.

[0192] The link layer must listen for the completion of all scan intervals in the scan window, as directed by the host, provided there are no scheduling conflicts. In each scan window, the link layer must scan a different advertising channel index. The link layer uses all available advertising channel indices.

[0193] In passive scanning, the link layer only receives packets and does not transmit any packets.

[0194] When actively scanning, the link layer listens to the advertising device for advertising PDUs and depending on the advertising PDU type, may request additional information about the advertising device.

[0195] Initiating State

[0196] The link layer enters the initiated state at the direction of the host (stack).

[0197] When the link layer is in the initiating state, the link layer listens for advertising channel indices.

[0198] During the initiation state, the link layer listens for advertising channel indices during the scan window period.

[0199] connection state

[0200] The link layer enters a connected state when the device performing the connection request, i.e., the initiating device, sends a CONNECT_REQ PDU to the advertising device, or when the advertising device receives a CONNECT_REQ PDU from the initiating device.

[0201] Once a connection enters the connected state, it is considered established. However, the connection need not be considered established at the time it enters the connected state. The only difference between a newly created connection and an established connection is the link-layer connection supervision timeout value.

[0202] When two devices are connected, they act in different roles.

[0203] The link layer that performs the master role is called the master, and the link layer that performs the slave role is called the slave. The master controls the timing of connection events, and connection events indicate the point in time when the master and slave are synchronized.

[0204] Below, we will briefly examine the packets defined in the Bluetooth interface. BLE devices use the packets defined below.

[0205] Packet Format

[0206] The Link Layer has only one packet format, which is used for both advertising channel packets and data channel packets.

[0207] Each packet consists of four fields: Preamble, Access Address, PDU, and CRC.

[0208] When a packet is transmitted on an advertising physical channel, the PDU will be an advertising channel PDU, and when a packet is transmitted on a data physical channel, the PDU will be a data channel PDU.

[0209] Advertising Channel PDU

[0210] Advertising channel PDUs (Packet Data Units) have a 16-bit header and payloads of various sizes.

[0211] The PDU type field of the advertising channel PDU included in the header indicates the PDU type as defined in Table 1 below.

[0212]

[0213] Advertising PDU

[0214] The advertising channel PDU types below are called advertising PDUs and are used in specific events.

[0215] ADV_IND: Connectable non-directional advertising event

[0216] ADV_DIRECT_IND: Connectable directional advertising event

[0217] ADV_NONCONN_IND: Non-directional ad event that is not reachable

[0218] ADV_SCAN_IND: Scannable non-directional ad event

[0219] The above PDUs are transmitted by the link layer in the advertising state and received by the link layer in the scanning state or initiating state.

[0220] Scanning PDU

[0221] The advertising channel PDU type below is called a scanning PDU and is used in the conditions described below.

[0222] SCAN_REQ: Sent by the link layer in scanning state and received by the link layer in advertising state.

[0223] SCAN_RSP: Sent by the link layer in advertising state and received by the link layer in scanning state.

[0224] Initiating PDU

[0225] The advertising channel PDU type below is called an initiation PDU.

[0226] CONNECT_REQ: Sent by the link layer in the initiating state and received by the link layer in the advertising state.

[0227] Data Channel PDU

[0228] A data channel PDU has a 16-bit header, a payload of variable size, and may include a Message Integrity Check (MIC) field.

[0229] The procedures, states, packet formats, etc. in BLE technology discussed above can be applied to perform the methods proposed in this specification.

[0230] Figure 4 shows an example of the structure of the GATT (Generic Attribute Profile) of Bluetooth low energy.

[0231] Referring to Figure 4, a structure for exchanging profile data of Bluetooth low energy can be examined.

[0232] Specifically, GATT (Generic Attribute Profile) defines how to exchange data using services and characteristics between Bluetooth LE devices.

[0233] Typically, a peripheral device (e.g., a sensor device) acts as a GATT server and has definitions for services and characteristics.

[0234] To read or write data, a GATT client sends a data request to a GATT server, and all operations (transactions) are initiated by the GATT client and receive responses from the GATT server.

[0235] The GATT-based operation structure used in Bluetooth LE is based on profiles, services, and characteristics, and can form a vertical structure as shown in Fig. 5.

[0236] The above profile consists of one or more services, and the services may consist of one or more characteristics or other services.

[0237] The above service serves to logically divide data into units and may include one or more characteristics or other services. Each service has a 16-bit or 128-bit identifier called a Universal Unique Identifier (UUID).

[0238] The above characteristic is the lowest unit in the GATT-based operation structure. The characteristic contains only one piece of data and, similar to the above service, has a 16-bit or 128-bit UUID.

[0239] The above characteristics are defined by the values ​​of various pieces of information, and each piece of information requires one attribute. Multiple consecutive attributes can be used for the above characteristics.

[0240] The above attribute consists of four components and has the following meanings:

[0241] - handle: address of the property

[0242] - Type: Type of property

[0243] - Value: The value of the property

[0244] - Permission: Access rights to properties

[0245] FIG. 5 is a flowchart showing an example of a connection procedure method in Bluetooth low energy technology to which the present invention can be applied.

[0246] The server transmits advertising messages to the client through three advertising channels (S5010).

[0247] A server may be called an Advertiser before connection, and a Master after connection. An example of such a server may be a sensor (e.g., a temperature sensor).

[0248] Additionally, a client may be referred to as a "Scanner" before connection and as a "Slave" after connection. An example of a client may be a smartphone.

[0249] As previously discussed, Bluetooth communicates across 40 channels over the 2.4 GHz band. Of these 40 channels, three are advertising channels, used to exchange various advertising packets and other packets used to establish a connection.

[0250] The remaining 37 channels are used for data exchange after connection as data channels.

[0251] After receiving the advertisement message, the client may send a Scan Request message to the server to obtain additional data (e.g., server device name, etc.) from the server.

[0252] In this case, the server transmits a Scan Response message containing additional data in response to a Scan Request message to the client.

[0253] Here, the Scan Request message and the Scan Response message are an end of an advertising packet, and the advertising packet can only contain user data of 31 bytes or less.

[0254] Therefore, if there is data whose size is larger than 3 bytes but the overhead is too high to send the data by establishing a connection, the data is sent in two parts using a scan request message / scan response message.

[0255] Next, the client sends a connection request message to the server to establish a Bluetooth connection with the server (S5020).

[0256] Through this, a Link Layer (LL) connection is established between the server and the client.

[0257] Afterwards, the server and client perform security establishment procedures.

[0258] The secure establishment procedure may be interpreted as or performed incorporating Secure Simple Pairing.

[0259] That is, the security establishment procedure can be carried out through Phase 1 to Phase 3.

[0260] Specifically, a pairing procedure (phase 1) is performed between the server and the client (S5030).

[0261] The pairing procedure involves the client sending a pairing request message to the server, and the server sending a pairing response message to the client.

[0262] The pairing process involves exchanging authentication requirements, input / output capabilities, and key size information between devices. This information is used to determine which key generation method to use in Phase 2.

[0263] Next, as phase 2, legacy pairing or secure connections are performed between the server and the client (S5040).

[0264] In Phase 2, a 128-bit temporary key and a short term key (STK) are generated to perform legacy pairing.

[0265] - Temporary Key: Key created to generate STK

[0266] - Short Term Key (STK): Key value used to create an encrypted connection between devices.

[0267] If a secure connection is performed in Phase 2, a 128-bit Long Term Key (LTK) is generated.

[0268] - Long Term Key (LTK): A key value used not only for encrypted connections between devices but also for future connections.

[0269] Next, as phase 3, a key distribution procedure is performed between the server and the client (S5050).

[0270] This establishes a secure connection between the server and client, forming an encrypted link to enable data transmission and reception.

[0271] Isochronous Channel General

[0272] For audio signals, you can see that audio streaming data or audio data occurs periodically at Idle Event Interval intervals.

[0273] Audio data occurs periodically (or at specific time intervals) depending on its characteristics. Here, a specific time period during which audio data occurs periodically can be expressed as an Idle Event Interval. Each audio data is transmitted during each Idle Event Interval. Furthermore, each audio data can be transmitted throughout the entire Idle Event Interval or a portion of the Idle Event Interval. When transmitting audio streaming data that occurs periodically or regularly using the BLE mechanism, advertising and scanning procedures, communication procedures, and disconnection procedures must be performed each time the generated audio data is transmitted or received. However, audio data is generally generated periodically, and regardless of the amount of data, a latency guarantee for audio data transmission is essential.

[0274] However, there is a problem that latency occurs in audio data transmission when advertising and scanning procedures, communication procedures, and disconnection procedures must be performed every time new audio data is transmitted.

[0275] Audio data transmission through hearing aids (HA) or headsets can achieve higher energy efficiency by utilizing BLE technology rather than Bluetooth BR / EDR technology because the amount of data generated is relatively small. However, as previously discussed, the Data Channel Process of BLE technology requires advertising and connection for each data transmission, which results in a large overhead in data transmission. In particular, the Latency Guarantee, which is absolutely necessary for audio data transmission, cannot be guaranteed.

[0276] In addition, since the Data Channel Process of BLE technology aims to increase energy efficiency by transmitting data that occurs sporadically only when necessary and inducing deep sleep of the BLE device in other time domains, it may be difficult to apply the Data Channel Process of BLE technology to the transmission of audio data that occurs periodically.

[0277] Definition of Isochronous Channels and Related Mechanisms

[0278] A new channel, the Isochronous Channel, is defined to transmit periodically occurring data using BLE technology.

[0279] An isochronous channel is a channel used to transmit isochronous data between devices that use isochronous streams (e.g., Conductor-Member).

[0280] Isochronous data refers to data that is transmitted periodically or regularly at specific time intervals.

[0281] That is, an isochronous channel may refer to a channel through which periodically occurring data, such as audio data or voice data, is transmitted and received in BLE technology. In addition, the isochronous channel may refer to a channel through which data generated based on a user input of a game user's controller device is transmitted and received in a gaming scenario. The isochronous channel may be used to transmit and receive data with a single member, a set of one or more coordinated members, or multiple members. In addition, the isochronous channel corresponds to a flushing channel that may be used to transmit and receive important data in an isochronous stream, such as audio streaming, or in another time domain.

[0282] FIG. 6 illustrates an example of a system structure in which multi-channel audio signals are transmitted between a BLE-based TV transmitting device and multiple BLE audio receiving speakers.

[0283] Figure 6 illustrates an example system architecture that wirelessly transmits multi-channel audio signals between a TV transmitter and multiple audio receiver speakers using BLE (Bluetooth Low Energy) technology. The system of Figure 6 configures the TV as an audio transmitter (Initiator) and each speaker as an audio receiver (Acceptor), enabling a multi-channel audio environment without wired connections. It utilizes BLE's ISO channel, making it suitable for audio data transmission where time synchronization is critical.

[0284] The TV LE Audio Tx Device includes a video display, an audio decoder / encoder, a controller, and a BLE Tx interface. The audio decoder / encoder converts surround audio formats such as Dolby or DTS into PCM and encodes it into the LC3 codec suitable for BLE transmission. It also supports mono unicast transmission. The TV wirelessly transmits the processed audio signal to external speakers via the BLE Tx interface. Configuration information can be communicated bidirectionally, while the actual audio stream is transmitted unidirectionally.

[0285] The Speaker LE Audio Rx Device consists of a BLE Tx / Rx interface, an audio decoder, an LC3 decoder, a controller, and a speaker driver. Each speaker receives BLE audio data wirelessly transmitted from the TV through the BLE Tx / Rx interface. The received data is restored to the original audio signal through the LC3 decoder and audio decoder, and this signal is output as sound through the speaker driver. Speakers with Tx / Rx interfaces can be used for exchanging setting information with the TV or receiving control signals.

[0286] The system in Figure 6 operates by processing multichannel audio signals, such as 5.1 channels, from a TV and assigning and transmitting them to wireless speakers, either individually or in groups. Each speaker receives and plays audio data for its assigned channel, allowing users to experience a wireless surround sound system without the need for complex audio cable connections. This offers the advantage of increased installation flexibility and a cleaner user experience.

[0287] Figure 7 illustrates an example of a procedure in which an audio transmitting device transmits an audio signal to multiple audio receiving devices in a unicast manner.

[0288] An audio transmitting device (source device) (e.g., a TV) can transmit audio signals to multiple audio receiving devices (sink devices) (e.g., speakers) in a unicast manner.

[0289] For example, some speakers (e.g., two speakers) of the plurality of audio receiving devices may be built into the audio transmitting device.

[0290] Referring to Figure 7, the TV, which is an audio transmitting device, has a front left (FL) speaker and a front right (FR) speaker built in. In other words, the TV can play the FL channel and the FR channel through its own built-in speakers.

[0291] The TV can wirelessly transmit audio signals to the rear left (RL) speaker and the rear right (RR) speaker, respectively, through the RL channel and the RR channel.

[0292] The TV receives GA (General Announcement) or TA (Target Announcement) from multiple speakers.

[0293] GA refers to advertising in which the speaker transmits an advertisement packet containing simple information that the device is ready without specifying the target.

[0294] TA refers to an advertisement in which a speaker transmits an advertisement packet containing information such as the device's role (RR or RL) and decoder performance to a designated central device by specifying an address so that the central device can receive it.

[0295] The TV is set to play FL channel and FR channel (and / or center (C) channel) audio using its built-in speakers.

[0296] The TV makes a connection request to the RL speaker and RR speaker based on the received advertisement (Connect Req. in Fig. 7).

[0297] The TV is set to the role of a central device, and the RL speaker and RR speaker are set to the role of peripheral devices. The connection request and the role setting can be set based on the GATT layer.

[0298] The TV establishes a unicast connection for transmitting audio signals to each of the RL and RR speakers based on the link layer. The unicast connection may be a CIS (Connected Isochronous Stream).

[0299] For example, an RL channel audio signal and an RR channel audio signal can be transmitted through each CIS.

[0300] For example, the CIS for the RL channel and the CIS for the RR channel may be included in one CIG (Connected Isochronous Group).

[0301] The TV can identify the left and right positions of each of the connected speakers through the TA step or the PAC (Published Audio Capability) discovery procedure after connection.

[0302] The PAC field is structured as shown in Table 2 below.

[0303]

[0304] Each speaker connected wirelessly to the TV transmits information about its location in a packet so that the TV can know it. The location (e.g., left, right) can be included in the Audio Location Field of the PAC format.

[0305] Figure 8 illustrates an example of a procedure in which an audio transmitting device transmits an audio signal to a plurality of audio receiving devices in a broadcast manner.

[0306] The TV can wirelessly transmit audio signals to the rear left (RL) speaker and the rear right (RR) speaker, respectively, through the RL channel and the RR channel.

[0307] Referring to FIG. 8, the TV establishes a broadcast channel for transmitting audio signals to each of the RL speaker and the RR speaker based on the link layer. The broadcast channel may be a BIS (Broadcast Isochronous Stream) channel.

[0308] For example, an RL channel audio signal and an RR channel audio signal can be transmitted based on a single BIS. At this time, the RL channel data and RR channel data can be distinguished through a sequence number (Seq#).

[0309] As another example, the RL channel audio signal and the RR channel audio signal can be transmitted based on their respective BISs.

[0310] For example, the BIS for the RL channel and the BIS for the RR channel may be included in one BIG (Broadcast Isochronous Group).

[0311] Figure 9 illustrates an example of hardware having two speakers built into an audio transmitting device.

[0312] Figure 9 specifically shows a system configuration that distributes the audio of an audio transmitting device (e.g., a TV) to multiple speakers by utilizing BLE audio technology.

[0313] The original audio output from the TV is a multichannel surround sound format (e.g., a Dolby 5.1-channel stream). This stream is converted / decoded into PCM via a decoder (e.g., a Dolby 5.1-channel decoder), and each channel is separated into PCM. The channels can be configured as FL, FR, RL, RR, C, and / or W (woofer).

[0314] Referring to Fig. 9, the TV includes built-in speakers. If the TV has built-in FL speakers, FR speakers, a center speaker, and a woofer, FL PCM, FR PCM, C PCM, and W PCM can be transmitted to the TV's built-in speakers.

[0315] The TV encodes RL PCM and RR PCM into an LC3 codec suitable for BLE transmission to wirelessly transmit them to RL speakers and RR speakers, respectively. The encoding can be performed by an LC3 Encoder.

[0316] The encoded RL LC3 and RR LC3 are transmitted / streamed to the RL speaker and RR speaker via the BLE transmission interface.

[0317] The speakers receive audio data encoded with the LC3 codec via the BLE receiver interface. The speakers then use the LC3 decoder to reconstruct the audio data into its original audio signal and play it back.

[0318] Distance measurement methods using Bluetooth technology include i) coarse measuring method, ii) direction finding method, and iii) high accuracy measuring method.

[0319] The most basic Bluetooth distance measurement method is based on the Received Signal Strength Indicator (RSSI). Specifically, the stronger the signal, the closer the distance. This method has a resolution of less than 50 cm within a radius of about 10 meters and is primarily used for beacon advertising, which alerts users when they approach a specific location.

[0320] Direction finding methods measure the direction angle using AOA (Angle of Arrival) or AoD (Angle of Departure) technology, and based on this, the distance is measured using triangulation. AoA is a technology that measures the angle at which a signal arrives. It is a technology that uses multiple antennas in the receiving device to analyze the time difference between the signal reaching each antenna and calculates the direction. AoD is a technology that measures the angle at which a signal departs. It is a technology that uses multiple antennas in the transmitting device to transmit signals in multiple directions and the receiving device receives these signals and determines the direction. Due to the characteristics of AoA and / or AoD technology, two or more antennas are required, and the resolution is approximately 50 cm at a radius of about 10 m.

[0321] This high-precision measurement method is a channel sounding-based distance measurement method that combines Time of Flight (ToF) and Phase Range technologies to measure distance. ToF calculates distance by measuring the time it takes for a signal to be transmitted and received, while Phase Range estimates distance by measuring the phase change of a signal across multiple frequency channels. It has a resolution of approximately 20-30cm at a 10m radius, offering significantly higher precision than existing methods. This method can transmit signals using ASK modulation using 72 physical layer channels.

[0322] FIG. 10 illustrates an example of a channel sounding procedure according to an embodiment of the present specification.

[0323] Figure 10 illustrates a channel sounding procedure between two devices (nodes) (Initiator and Responder).

[0324] First, a BLE connection is established between the two devices. The two devices then exchange their capabilities and negotiate the configuration for the channel sounding procedure. This configuration may include, for example, the frequency channel to be used and the measurement cycle.

[0325] Before the channel sounding procedure begins, communication security is activated. This ensures the integrity and reliability of the measurement data. Once security is established, the channel sounding procedure begins.

[0326] Within the channel sounding procedure, several small subevents occur repeatedly, and during each subevent, the initiator and responder transmit and receive radio signals to collect data about the channel characteristics.

[0327] After each sub-event, the two devices exchange their collected measurement results. These measurement results may include information necessary for distance calculation, such as signal arrival time, phase, and intensity.

[0328] The sub-event and measurement result exchange steps of the above channel sounding procedure are repeated for all physical channels for which the channel sounding procedure is requested (e.g., up to 72 channels).

[0329] Once the channel sounding procedure for all requested physical channels is completed, the process ends. The measurement results collected at the link layer are passed to the application within the device, which uses a distance estimation algorithm to calculate the final distance between the two devices.

[0330] FIG. 11 illustrates an example of a device for receiving information related to the distance between measured speakers according to an embodiment of the present disclosure.

[0331] Referring to Figure 11, information related to the distance between speakers is shown being transmitted to a specific device used by the user (e.g., a smartphone or remote control).

[0332] In a multi-channel audio transmission environment, each of the multiple speakers can measure the distance between itself and other speakers based on the channel sounding procedure described above. In this manner, the distances between all speakers can be measured, and these measured distances can be collected by a specific device (e.g., a user's smartphone or remote control). Based on the collected distances, the specific device can estimate the channels / relative positions of the multiple speakers.

[0333] For example, the estimation of the channels / relative positions may be based on distance-based localization and / or multilateration.

[0334] For 5.1 channels, the channels / positions of the five speakers are the subject of the above estimation, excluding the subwoofer, which is not related to the position.

[0335] Each speaker node estimates its distance to other nodes through a channel sounding procedure.

[0336] Each node measures the distance to other speaker nodes excluding itself four times, and since there are five speakers in total, a total of 20 measurements are required. However, excluding the distance measurements between overlapping objects, the distances between five speakers can be measured with a total of 10 measurements.

[0337] The above channels / relative positions can be more easily estimated by applying general rules for speaker placement in a 5.1-channel surround speaker system. General rules for speaker placement are as follows:

[0338] 1) Each node is located on a two-dimensional circular plane.

[0339] 2) The center speaker is located directly in front of the listener, and the sum of the distances to all speakers is the smallest compared to the other speakers.

[0340] 3) The front left speaker and front right speaker are relatively close to the center speaker, and their positions are symmetrical with respect to the center speaker. For example, it can be assumed that the FL speaker and the FR speaker form an angle of approximately 30 degrees with respect to the listener.

[0341] 4) The rear left speaker and the rear rear speakers are positioned behind the listener and are symmetrical left and right with respect to the center speaker. For example, the RL speaker and the RR speaker may form an angle of approximately 110 to 120 degrees with respect to the listener.

[0342] 5) Woofers (subwoofers) are not affected by location.

[0343] The estimation of the above channels / opponent locations can be based on least-squares fitting or Bayesian inference for more precise estimation.

[0344] In one embodiment, based on such general rules, the specific device can estimate the channels of the speakers through the distance estimation algorithm.

[0345] First, to estimate channels, we create an empty graph (Distances) with five nodes. Then, we input the distance weight (meter) between each edge.

[0346] For example, a distance vector of five points can be generated for applying a channel estimation algorithm.

[0347] Based on the filled graph, the channels of each speaker are estimated in the following order.

[0348] For each node, the sum of the distances to other nodes is calculated. The node with the smallest sum of distances to other nodes is estimated to correspond to the center (C) channel.

[0349] For example, by adding up all the row values ​​of the generated Distances graph, the smallest row can be estimated as the row corresponding to the center channel.

[0350] Based on the node corresponding to the center channel, the two closest nodes are estimated to be nodes corresponding to the FL channel and the FR channel.

[0351] Among the remaining two nodes, the node that is relatively close to the node corresponding to the FL channel (or the node corresponding to the FR channel) is estimated to be the node corresponding to the RL channel (or the node corresponding to the RR channel).

[0352] For example, in the estimation of the FL channel and the FR channel, the left / right positions can be reversed, so that the FL channel and the FR channel can be finally estimated based on the test sound reproduction.

[0353] For example, the relative channels of the estimated speakers can be represented in a UI. The UI may include a TV screen and / or a smartphone screen.

[0354] In one embodiment, the relative positions of the speakers can be estimated using a distance vector that measures the distance between each speaker.

[0355] For example, for ease of calculation and to avoid errors, speakers may be assumed to be located in two-dimensional space.

[0356] For example, the relative positions of speakers can be estimated using Multi-Dimensional Scaling (MDS) in a two-dimensional space. In this case, the distance vector for MDS estimation can be a symmetric matrix.

[0357] For example, a node corresponding to the estimated center channel based on the above channel estimation can be estimated as the origin.

[0358] For example, nodes corresponding to the estimated FL and FR channels based on the channel estimation can be placed on the left and right of the reference point, respectively.

[0359] For example, in the position estimation of the FL speaker and FR speaker, a case in which the positions are estimated in reverse may be considered. In this case, the positions of the FL and FR speakers can be finally confirmed through test sound playback.

[0360] For example, the nodes corresponding to the channels for the rear speakers can be placed on opposite sides of the three speakers described above (C speaker, FL speaker, and FR speaker).

[0361] For example, since the x, y coordinates calculated by the position estimation algorithm have no directionality, the estimated positions of the speakers can be rotated so that the C speaker, FL speaker, and FR speaker are positioned at the top.

[0362] For example, the Angle estimation for the estimated positions can be modified by the user through the UI screen.

[0363] According to one embodiment, the above and the above location estimation methods estimate the location of the user through six nodes by using the user's device (e.g., a smartphone or a remote control) as a sixth device, so that the user's location can also be estimated.

[0364] The above location estimation method can be based on the MDS package provided in Python. In this case, Max_iteration=300. In this case, adjusting the convergence threshold, or Max_iteration, can help find a short critical time for commercial use.

[0365] FIGS. 12 and 13 illustrate an example of a procedure for estimating the positions of speakers based on measured distances between speakers according to an embodiment of the present disclosure.

[0366] Figures 12 and 13 are examples of estimating the positions of speakers by inputting the distances between each node into the actual distance_matrix.

[0367] Taking Fig. 12 as an example, each row of the distance_matrix corresponds to a node for each speaker, and corresponds to nodes A, B, C, D, and E in order from the top raw. The sum of the raw values ​​of each node is i) 17.52 for node A, ii) 17.03 for node B, iii) 20.83 for node C, iv) 17.69 for node D, and v) 19.57 for node E.

[0368] According to the above channel estimation / location estimation method, the B node with the smallest sum of raw values ​​is estimated to be the C channel / center speaker.

[0369] The A node (the first value of the B node, 3.05) and the C node (the third value of the B node, 3.74), which are closest to the B node corresponding to the center speaker, are estimated to be the FL channel / FL speaker and the FR channel / FR speaker, respectively. The FL speaker and the FR speaker are arranged to the left and right of the center speaker.

[0370] For example, the left / right direction can be ultimately estimated through actual test sound playback.

[0371] Among the remaining D nodes and E nodes, the E node, which is relatively close to the A node corresponding to the FL channel, is estimated to be an RL channel / RL speaker. The remaining D nodes are estimated to be RR channels / RR speakers. The RL speaker and the RR speaker are arranged on opposite sides of the C speaker, the FL speaker, and the FR speaker.

[0372] For example, after position estimation is completed, the positions of all speakers can be rotated so that the C speaker, the FL speaker, and the FR speaker are positioned at the top.

[0373] As distance increases, sound pressure decreases proportionally to the square of the distance. If the distance between the listener and all speakers is not consistent, the listener will perceive differences in volume. These volume differences significantly reduce the listener's immersion and sense of presence in the content. Furthermore, not all spaces can provide optimal surround sound, and spatial arrangements may be asymmetrical left / right and / or up / down.

[0374] According to an embodiment of the present specification, i) a method for resolving a volume difference caused by a difference in default values ​​of sound pressure / volume between speakers, and ii) a method for resolving a volume difference / delay difference in an asymmetrical space are proposed.

[0375] Figure 14 is a diagram illustrating a case where the distances between the front speakers and the rear speakers and the user are different.

[0376] Referring to Figure 14, the rear speakers are shown to be located further away from the listener than the TV speakers (e.g., 3 meters), causing sound from the rear speakers to arrive at the listening position later than sound from the TV speakers. Even though the systems transmit audio signals simultaneously, the listener experiences a temporal mismatch in sound due to the physical distance difference.

[0377] Figure 15 is a diagram illustrating a case where the rear speakers are at different distances from the user. Figure 15 shows the effect of the distance difference between the rear speakers on synchronization.

[0378] Referring to Figure 15, the left and right rear speakers may not be positioned exactly the same distance from the listener, as illustrated in the figure, where one rear speaker is slightly further away (e.g., 3 meters) than the other. Even these slight differences in distance between speakers can cause sound to travel at different times, and especially in sophisticated surround sound environments, these errors can lead to distortion of the sound image.

[0379] Figure 16 is a diagram illustrating the decreasing trend of sound pressure according to the distance from the speaker.

[0380] When the distance doubles, the sound pressure decreases by 1 / 4 (6 dB). Even if the initial default sound pressure / volume of each speaker is set to the same, the sound pressure / volume heard by the viewer may vary due to the difference in distance. To address this, a method is proposed to adjust the volume / delay so that the volume is heard the same at the viewer's position by considering both the case where the default sound pressure / volume values ​​of each speaker are different and the case where the distance between each speaker and the viewer is different.

[0381] When you first power on your Bluetooth portable speakers, it may be that the default sound pressure / volume is set differently for each speaker.

[0382] In one embodiment, the default value of the speaker's sound pressure / volume can be measured through the mic of the user's device (e.g., a smartphone or remote control).

[0383] For example, the reference for the sound pressure / volume of the speaker used for the above measurement can be i) a single frequency tone sound or ii) a mix of tones of multiple frequencies. The reference for the sound pressure / volume can be pink noise.

[0384] For example, if the default values ​​of the sound pressure / volume of the speakers are different from each other, the sound pressure / volume between the speakers can be adjusted using the BT Volume Control command.

[0385] For example, the reference for the above sound pressure / volume adjustment can be set to the center speaker. In other words, the sound pressure / volume of the other speakers can be adjusted based on the center speaker.

[0386] Below, a method for compensating for volume differences and delay differences in asymmetric space is proposed.

[0387] FIG. 17 illustrates an example of an overall procedure for adjusting the volume and delay of multiple speakers according to an embodiment of the present disclosure. More specifically, FIG. 17 illustrates an overall procedure for a method for adjusting volume based on the Bluetooth Volume Control Profile in an asymmetric space.

[0388] For example, a device (e.g., a smartphone or remote control) that measures the volume of speakers for volume control can be omitted because the volume is measured while held by the listener (user).

[0389] Referring to Figure 17, the procedure for adjusting the volume by connecting a VC Client (e.g., a smartphone or remote control) to each VC Server (speaker) is shown.

[0390] Each speaker transmits an advertisement to the VC Client, and the VC Client detects the advertisement through scanning and establishes a BLE connection with each speaker.

[0391] After a connection is established, the VC Client discovers the services / characteristics offered by each speaker. This process allows the VC Client to understand the capabilities of each speaker. For example, services / characteristics may include ASCS (Audio Stream Control Service), PACS (Published Audio Capabilities Service), VCS (Volume Control Service), and MCHS (Multi-Channel Home Sound).

[0392] Based on the information received during the service / feature discovery process, the VC Client can then identify more detailed audio-related information for each speaker, such as Audio Role, Codec Capability, ASE_ID, Audio context, and Speaker Capability Discovery. Audio Role indicates the speaker's role (e.g., which channel it is in charge of). ASE_ID is a unique identifier for the audio stream endpoint and is used for stream management. Audio context indicates the type of audio currently being played, which can affect how the audio is processed. Speaker Capability Discovery is used to identify detailed capabilities of the speaker, such as the physical audio location, via PAC.

[0393] Afterwards, the VC Client sets the encoding parameters of the audio codec to be sent to each speaker based on the capabilities of the speakers received in the previous step, and negotiates QoS (Quality of Service) parameters (e.g., delay time, packet loss tolerance, etc.) with each speaker.

[0394] In the subsequent steps, the VC Client will perform a procedure to calibrate the volume and / or delay, and then stream the audio signal.

[0395] Referring to FIGS. 18 and 19 below, the compensation procedure for the volume / delay is described in more detail.

[0396] FIG. 18 illustrates an example of a volume adjustment procedure for multiple speakers according to an embodiment of the present specification.

[0397] Referring to Figure 18, a VC Client (e.g., a smartphone) is shown connected to multiple VC Servers (e.g., speakers).

[0398] For example, the initial volume reference could be set to a default value based on i) the usual SPL of the TV, or ii) the expected value in a movie viewing environment of 70-75 dB.

[0399] For example, VC Client connects one-to-one with each speaker and can sequentially adjust the volume / sound pressure of the speakers.

[0400] For example, a VC Client can receive a volume level from a speaker. It can then instruct the speaker to set a preset / defined volume level and play a reference sound / test sound. As a specific example, the reference sound / test sound may be pink noise.

[0401] The VC Client can measure the SPL level based on the pink noise being played. It can then adjust the volume / sound pressure of the corresponding speaker based on the SPL level. The speaker used as the reference for volume / sound pressure adjustment can be a TV or center speaker.

[0402] Once the VC Client has completed the adjustment for that speaker, it can proceed with the volume / adjustment procedure for the next speaker.

[0403] FIG. 19 illustrates an example of a delay adjustment procedure for multiple speakers according to an embodiment of the present specification.

[0404] Referring to Figure 19, the process of the Initiator collecting distance information by measuring the distance to each speaker through delay adjustment is shown.

[0405] For example, the distance between a VC Client and multiple speakers can be measured based on the channel sounding procedure described above.

[0406] For example, measured distance information can be collected by an initiator (e.g., a smartphone).

[0407] The initiator can transmit play delay information to each speaker based on the distance information collected.

[0408] For example, the delay adjustment may be performed based on the speaker furthest from the initiator.

[0409] The embodiments described below are specifically described with reference to FIG. 20 in terms of the operation of electronic devices (e.g., TV devices). The methods described below are distinguished for convenience of explanation, and it is understood that some components of one method may be substituted for or combined with some components of another method, as long as they are not mutually exclusive.

[0410] FIG. 20 is a flowchart illustrating a method according to one embodiment of the present specification.

[0411] Referring to FIG. 20, a method according to one embodiment of the present specification includes a step of receiving information related to first distances between speakers (S2001) and a step of determining relative positions of the speakers (S2002).

[0412] At step S2001, the electronic device can receive information relating to first distances between speakers.

[0413] The above first distances are measured based on a channel sounding procedure between the speakers.

[0414] At step S2002, the electronic device can determine the relative positions of the speakers based on the information.

[0415] In one embodiment, the relative positions may be determined based on the sum of the distances of each of the speakers to the other speakers.

[0416] For example, i) among the speakers, the speaker with the smallest sum of distances to other speakers may be determined as the center speaker, ii) among the speakers, a predetermined number of speakers that are relatively close to the center speaker may be determined as front speakers, and iii) among the speakers, the remaining speakers may be determined as rear speakers.

[0417] As a specific example, among the above speakers, two speakers that are relatively close to the center speaker can be determined as front speakers.

[0418] For example, the front speakers may include a front left (FL) speaker and a front right (FR) speaker, and the rear speakers may include a rear left (RL) speaker and a rear right (RR) speaker.

[0419] For example, among the front speakers, the FL speaker and the FR speaker can be determined based on test sound reproduction.

[0420] For example, i) among the rear speakers, a speaker that is relatively close to the FL speaker may be determined as the RL speaker, or ii) among the rear speakers, a speaker that is relatively close to the FR speaker may be determined as the RR speaker.

[0421] In one embodiment, the step of determining the relative positions (S2002) may include the step of measuring second distances between the electronic device and the speakers based on the channel sounding, and the step of determining the relative positions of the electronic device and the speakers based on the information and the second distances.

[0422] In one embodiment, the step of determining the relative positions (S2002) may further include a step of transmitting information related to a delay adjusted based on the second distances to each of the speakers.

[0423] For example, the delay may be adjusted based on the speaker that is relatively farthest from the electronic device among the speakers.

[0424] In one embodiment, the method may further include the steps of transmitting a test audio signal to each of the speakers, measuring a sound pressure level (SPL) of each of the speakers based on the test audio played back by each of the speakers, and adjusting a volume of each of the speakers based on the SPL.

[0425] For example, the volume of other speakers can be adjusted based on the SPL of the center speaker among the above speakers.

[0426] According to various embodiments of the present disclosure, an electronic device is provided. The electronic device includes one or more transceivers, one or more processors, and one or more memories that store instructions that, when executed by the one or more processors, perform operations. The operations may include an operating method of the electronic device according to FIG. 20.

[0427] For example, the one or more processors may include a first processor corresponding to a host stack and a second processor corresponding to a first controller stack. As a specific example, the host stack and the controller stack may be connected via a Host Controller Interface (HCI).

[0428] According to various embodiments of the present disclosure, a control device for controlling an electronic device is provided. The control device includes at least one processor and at least one memory operably connected to the at least one processor. The at least one memory may be configured to store instructions for performing an operating method of the electronic device according to FIG. 20 based on instructions executed by the at least one processor.

[0429] According to various embodiments of the present disclosure, one or more non-transitory computer-readable media (CRM) storing one or more instructions are provided. The one or more instructions, when executed by one or more processors, perform operations, and the operations may include an operating method of an electronic device according to FIG. 20.

[0430] The embodiments described below are specifically described with reference to FIG. 21 in terms of speaker operation. The methods described below are distinguished for convenience of explanation, and it is understood that some components of one method may be substituted for or combined with some components of another method, as long as they are not mutually exclusive.

[0431] FIG. 21 is a flowchart illustrating a method according to another embodiment of the present specification.

[0432] Referring to FIG. 21, a method according to another embodiment of the present specification includes a step of measuring first distances between speakers (S2101) and a step of transmitting information related to the first distances (S2102).

[0433] At step S2101, the speaker measures first distances between the speakers to determine relative positions of the speakers.

[0434] The above first distances are measured based on a channel sounding procedure between the speakers.

[0435] At step S2102, the speaker transmits information related to first distances between the speakers to the device.

[0436] In one embodiment, the relative positions may be determined based on the sum of the distances of each of the speakers to the other speakers.

[0437] For example, i) among the speakers, the speaker with the smallest sum of distances to other speakers may be determined as the center speaker, ii) among the speakers, a predetermined number of speakers that are relatively close to the center speaker may be determined as front speakers, and iii) among the speakers, the remaining speakers may be determined as rear speakers.

[0438] For example, the front speakers may include a front left (FL) speaker and a front right (FR) speaker, and the rear speakers may include a rear left (RL) speaker and a rear right (RR) speaker.

[0439] For example, among the front speakers, the FL speaker and the FR speaker are determined based on test sound reproduction.

[0440] In one embodiment, the method may further include receiving information from the electronic device relating to an adjusted delay based on second distances between the electronic device and the speakers.

[0441] For example, the second distances can be measured based on the channel sounding.

[0442] The above delay can be adjusted based on the speaker that is relatively farthest from the electronic device among the speakers.

[0443] In one embodiment, the method may further include the steps of receiving a test audio signal from the electronic device, playing test audio based on the test audio signal, receiving an audio signal from the electronic device based on an adjusted volume, and playing audio based on the audio signal.

[0444] For example, the volume may be adjusted based on a measured sound pressure level (SPL) based on the test audio.

[0445] For example, the volume is adjusted based on the SPL of the center speaker among the speakers.

[0446] According to various embodiments of the present disclosure, a speaker is provided. The speaker includes one or more transceivers, one or more processors, and one or more memories that store instructions that, when executed by the one or more processors, perform operations. The operations may include a method of operating the speaker according to FIG. 21.

[0447] The one or more processors may include a third processor corresponding to a host stack and a fourth processor corresponding to a third controller stack. The host stack and the controller stack may be connected via a Host Controller Interface (HCI).

[0448] According to various embodiments of the present disclosure, a control device for controlling a speaker is provided. The control device includes at least one processor and at least one memory operably connected to the at least one processor. The at least one memory may be configured to store instructions for performing a method for operating a speaker according to FIG. 21 based on instructions executed by the at least one processor.

[0449] According to various embodiments of the present disclosure, one or more non-transitory computer-readable media (CRM) storing one or more instructions are provided. The one or more instructions, when executed by one or more processors, perform operations, and the operations may include a method of operating a speaker according to FIG. 21.

[0450] The claims described in the various embodiments of this specification may be combined in various ways. For example, the technical features of the method claims of the various embodiments of this specification may be combined and implemented as a device, and the technical features of the device claims of the various embodiments of this specification may be combined and implemented as a method. Furthermore, the technical features of the method claims of the various embodiments of this specification may be combined with the technical features of the device claims of the various embodiments of this specification may be combined and implemented as a device, and the technical features of the method claims of the various embodiments of this specification may be combined with the technical features of the device claims of the various embodiments of this specification may be combined and implemented as a method.

Claims

1. In a method of operating an electronic device in a short-range wireless communication system, A step of receiving information related to first distances between speakers; and A step of determining the relative positions of the speakers based on the above information; A method, characterized in that the above first distances are measured based on a channel sounding procedure between the speakers.

2. In paragraph 1, A method, characterized in that the above relative positions are determined based on the sum of the distances of each of the speakers to other speakers.

3. In paragraph 2, i) Among the above speakers, the speaker with the smallest sum of distances to other speakers is determined as the center speaker, ii) Among the above speakers, a predetermined number of speakers that are relatively close to the center speaker are determined as front speakers, iii) A method characterized in that the remaining speakers among the above speakers are determined to be rear speakers.

4. In paragraph 3, The above front speakers include a front left (FL) speaker and a front right (FR) speaker, A method, characterized in that the rear speakers include a rear left (RL) speaker and a rear right (RR) speaker.

5. In paragraph 4, A method characterized in that among the front speakers, the FL speaker and the FR speaker are determined based on test sound reproduction.

6. In paragraph 4, i) Among the rear speakers, a speaker that is relatively close to the FL speaker is determined as the RL speaker, or ii) A method characterized in that among the rear speakers, a speaker that is relatively close to the FR speaker is determined as the RR speaker.

7. In paragraph 1, The step of determining the above relative positions is: A step of measuring second distances between the electronic device and the speakers based on the channel sounding; and A method characterized by comprising the step of determining relative positions of the electronic device and the speakers based on the above information and the second distances.

8. In paragraph 7, Further comprising a step of transmitting information related to the adjusted delay based on the second distances to each of the speakers; A method characterized in that the delay is adjusted based on the speaker among the speakers that is relatively farthest from the electronic device.

9. In paragraph 1, A step of transmitting a test audio signal to each of the above speakers; A step of measuring the sound pressure level (SPL) of each of the speakers based on the test audio played by each of the speakers; and A method characterized in that it further comprises a step of adjusting the volume of each of the speakers based on the SPL.

10. In paragraph 9, A method characterized in that the volume of other speakers is adjusted based on the SPL of the center speaker among the above speakers.

11. In a method for operating a speaker included in a plurality of speakers in a short-range wireless communication system, A step of measuring first distances between the speakers to determine the relative positions of the speakers; and A step of transmitting information related to first distances between the speakers to the device; A method, characterized in that the above first distances are measured based on a channel sounding procedure between the speakers.

12. In paragraph 11, A method, characterized in that the above relative positions are determined based on the sum of the distances of each of the speakers to other speakers.

13. In paragraph 12, i) Among the above speakers, the speaker with the smallest sum of distances to other speakers is determined as the center speaker, ii) Among the above speakers, a predetermined number of speakers that are relatively close to the center speaker are determined as front speakers, iii) A method characterized in that the remaining speakers among the above speakers are determined to be rear speakers.

14. In paragraph 13, The above front speakers include a front left (FL) speaker and a front right (FR) speaker, A method, characterized in that the rear speakers include a rear left (RL) speaker and a rear right (RR) speaker.

15. In paragraph 14, A method characterized in that among the front speakers, the FL speaker and the FR speaker are determined based on test sound reproduction.

16. In paragraph 14, i) Among the rear speakers, a speaker that is relatively close to the FL speaker is determined as the RL speaker, or ii) A method characterized in that among the rear speakers, a speaker that is relatively close to the FR speaker is determined as the RR speaker.

17. In paragraph 11, Further comprising: a step of receiving information related to an adjusted delay from the electronic device based on second distances between the electronic device and the speakers; The above second distances are measured based on the channel sounding, A method characterized in that the delay is adjusted based on the speaker among the speakers that is relatively farthest from the electronic device.

18. In paragraph 11, A step of receiving a test audio signal from the electronic device; A step of playing test audio based on the above test audio signal; A step of receiving an audio signal from the electronic device based on the adjusted volume; and A step of playing audio based on the above audio signal; including: A method characterized in that the above volume is adjusted based on a sound pressure level (SPL) measured based on the above test audio.

19. In paragraph 18, A method characterized in that the above volume is adjusted based on the SPL of the center speaker among the above speakers.

20. In an electronic device in a short-range wireless communication system, One or more transceivers; one or more processors; and One or more memories storing instructions that perform operations when executed by said one or more processors; The above actions are, In a method of operating an electronic device in a short-range wireless communication system, A step of receiving information related to first distances between speakers; and A step of determining the relative positions of the speakers based on the above information; An electronic device, characterized in that the first distances are measured based on a channel sounding procedure between the speakers.

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