Wireless audio system and wireless audio transmission method based on WiFi

Abstract

The invention discloses a WiFi-based wireless audio system and a wireless audio transmission method, and relates to the technical field of wireless audio transmission. The wireless audio system provided by the invention comprises a sound source device and a receiving device, a wireless network BSS different from an AP is created locally through the sound source device, and the sound source device serves as a sending end in the BSS and can process acquired audio data so as to package the audio data of different audio channels in different data packets to be sequentially sent; the receiving device serves as a receiving end in the BSS, and can receive data packets corresponding to one or more audio channels configured by the receiving device from the data packets sent by the sound source device according to the configuration information of the receiving device and then play the data packets locally. According to the invention, based on the WiFi technology, the high bandwidth characteristic of WiFi is fully utilized, high-fidelity and multi-channel audio data transmission is realized, and the system has the flexibility similar to that of a Bluetooth audio technology.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless audio transmission, and in particular to a wireless audio system and a wireless audio transmission method based on WiFi. Background Art

[0002] Various wireless communication audio devices can be wirelessly connected to audio source devices such as computers, tablets, and mobile phones and receive audio data sent by the audio source devices. The audio source devices can run audio files, and the audio devices can output sound signals based on the audio data (including various speakers, amplifiers, headphones, etc.). The audio data provided by the audio source devices can be played through the audio devices. When there are multiple audio devices - for example, the left and right headphones in a wireless headset, each headset is an audio device. In order to improve the user's listening experience, it is usually required that the audio data be played synchronously between the audio devices.

[0003] In order to play audio data, a communication connection for transmitting audio data needs to be established between the audio source device and the audio device, and then the audio data is transmitted based on the connection. The commonly used connection method is mainly a wireless connection method based on the Bluetooth protocol. However, with the development of technology, people are no longer satisfied with the lossy audio data transmitted by Bluetooth. The existing technology provides various lossless audio transmission solutions based on WiFi (also known as WIFI or Wi-Fi).

[0004] As an example, for example, Chinese patent application CN201610651398.4 discloses a music synchronous playback method and playback system based on the WIFI protocol, the system comprising: a wireless access point, a main audio device wirelessly connected to the wireless access point, and a slave audio device wirelessly connected to the wireless access point and the main audio device; the main audio device is used to: obtain the first wireless data and audio data carrying a synchronization timestamp sent by the wireless access point and add a playback timestamp to form a second wireless data, extract the synchronization timestamp from the first wireless data, and synchronize the local clock in the main audio device to the synchronization timestamp; send the audio data and the second wireless data carrying the playback timestamp to the corresponding slave audio device; the slave audio device is used to: obtain the first wireless data carrying the synchronization timestamp sent by the wireless access point, extract the synchronization timestamp from the first wireless data, and synchronize the local clock in the slave audio device to the synchronization timestamp; obtain the audio data and the second wireless data carrying the playback timestamp sent by the main audio device, extract the playback timestamp from the second wireless data, and play the audio data according to the playback timestamp. The above solution utilizes the underlying protocol of the WIFI network and the timestamp in the Beacon data packet to achieve time synchronization of the multi-room system without increasing the network load and without utilizing the WIFI network clock synchronization protocol 802.11V.

[0005] However, the above solution requires wireless access points, master audio devices and slave audio devices to establish communication links with each other, which makes the network topology complex and the communication network difficult to maintain. Especially when there are a large number of audio devices, the transmission control and resource scheduling in the network are difficult. On the other hand, current wireless audio playback devices are usually powered by batteries, and how to reduce their power consumption during audio transmission is another important issue in wireless audio systems. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a wireless audio system and a wireless audio transmission method based on WiFi. The wireless audio system provided by the present invention includes a sound source device Source and a receiving device Sink. Another wireless network BSS (different from AP) is created locally through the sound source device Source. The sound source device Source acts as a transmitting end in the BSS network, and can process the acquired audio data to encapsulate the audio data of different audio channels Channel in different data packets Packets and send them in sequence; the receiving device Sink acts as a receiving end in the BSS network, and can receive data packets corresponding to one or more audio channels Channel configured by itself from the data packets sent by the sound source device according to its own configuration information, and then play the audio data locally. The present invention provides a wireless audio networking and communication solution based on WiFi by extending the existing WiFi technology, which makes full use of the high bandwidth characteristics of WiFi, can realize high-fidelity, multi-channel audio data transmission, and has the flexibility similar to Bluetooth audio technology.

[0007] To achieve the above objectives, the present invention provides the following technical solutions: A wireless audio system based on WiFi includes a sound source device Source and a receiving device Sink, wherein the sound source device Source and the receiving device Sink are provided with WiFi communication modules, and the sound source device Source is used to obtain audio data resources from the network; The audio source device Source is configured to: locally create a wireless network basic service set BSS consisting of itself and the aforementioned receiving device Sink; and, as a transmitter in the aforementioned BSS network, forward the acquired audio data to the Sink device in the BSS network, wherein the acquired audio data is processed to encapsulate the audio data of different audio channels Channel in different data packets and send them in sequence, and the sent data packets do not require the Sink device to reply with an ACK message; The receiving device Sink, as a receiving end in the BSS network, is configured to: receive data packets corresponding to one or more audio channels Channel configured by itself from the data packets sent by the sound source device according to its own configuration information; and locally play the audio data in the received data packets.

[0008] Further, after the audio source device Source establishes a communication link with a WiFi access point AP, it connects to a network through the AP to obtain audio data resources; or, The audio source device Source itself is a WiFi access point AP, which can connect to the network to obtain audio data resources; or, The audio source device Source itself is configured with a network connection function, and can connect to a wired network to obtain audio data resources or can connect to a wired radio broadcasting network to obtain audio data resources.

[0009] Furthermore, the processing of the acquired audio data by the audio source device Source includes: Extract audio data of different audio channels from the acquired audio data; Compress and encode the audio data of different audio channels; The compressed encoded data of different audio channels are encapsulated in different data packets and sent sequentially.

[0010] Furthermore, corresponding to the multiple audio channels Channel, the receiving device Sink is a plurality of audio playing devices arranged at different positions, and each receiving device Sink receives the data packets of the respective audio channels and then performs local synchronous playing; Alternatively, corresponding to multiple audio channels Channel, the receiving device Sink is the same audio playback device. In this case, the receiving device Sink can simultaneously receive data packets of multiple audio channels, mix the multiple data channels locally, and then play them synchronously.

[0011] Further, the audio source device Source, as a transmitter in the aforementioned BSS network, is configured to: broadcast a beacon Beacon configured with audio broadcast information, at this time, a new information element type audio broadcast is configured in the beacon Beacon, the audio broadcast information element includes scheduling layout information and audio information of the audio broadcast, the scheduling layout information is used to indicate the time, carrier frequency band and channel of each audio channel Channel, and the audio information is used to indicate the relevant information of the currently sent audio data; and after the aforementioned beacon Beacon is sent, send an audio data packet; The receiving device Sink, as the receiving end in the aforementioned BSS network, is configured to: perform a scanning operation to obtain the beacon Beacon sent by the aforementioned audio source device Source, and parse the relevant fields of the beacon Beacon; according to the audio broadcast information element configured in the beacon Beacon and the audio channel Channel type configured by the local device, selectively receive the continuous audio data packets following the aforementioned beacon Beacon; and, calculate the local playback time of the audio data packet, and play the corresponding audio data packet after the time point arrives.

[0012] Furthermore, the audio information Audio Information is organized in a hierarchical structured data format, with the top layer being the Audio Information general directory; the Audio Information general directory is provided with subdirectories, and there are one or more subdirectories; each subdirectory is provided with a channel Channel type, including one or more channel Channel types; The following parameter items are configured in the Audio Information general directory: playback time information, which is used to indicate how long the device needs to wait after receiving the audio data packet at the physical layer before playing the audio data in the data packet for synchronization of playback data of different audio channels; and sub-directory quantity information, which is used to indicate the number of sub-directories included in this directory; The subdirectory is configured with the following parameter items: Channel quantity information, used to indicate the number of audio channels; and Multimedia digital signal codec Codec type information, used to indicate the type of multimedia digital signal codec Codec; and, Sampling frequency information, used to indicate the sampling rate of audio; and, Frame playback duration information, used to indicate the duration of each frame time sent by the air interface when it is played; and, Number of bytes per frame, used to indicate the actual length of each frame; and, Audio type, used to indicate the type of audio; and, Language information, used to indicate the language type of audio data; The channel Channel type is configured with the following parameter items: channel ID, which corresponds to the configuration content of the audio channel Channel in the aforementioned scheduling layout information Schedule Map; and channel name.

[0013] Furthermore, multiple ID information is configured in the scheduling layout information Schedule Map, each ID information is associated with a channel ID under the channel Channel type in the audio information Audio Information, and the ID information is used to indicate the distribution of data packets during two beacon transmissions, as well as the number of retransmissions and the sorting relationship of the data packets.

[0014] Further, for multiple data packets belonging to the same Channel type, each data packet is configured to be sent Q times to increase the probability of the receiving device Sink receiving the packet, where Q is a natural number greater than or equal to 2; at this time, the receiving device Sink is configured to: after a data packet is successfully received, determine whether there is a retransmitted data packet behind the data packet, and if it is determined that there is a retransmitted data packet, do not receive the retransmitted data packet.

[0015] Further, the data packet distribution configuration indicated by the ID information includes: an interleaving mode configuration between data packets of the same Channel type, The corresponding interleaving mode is configured as follows: including a first mode, a second mode and a third mode, wherein the first mode is an interleaving mode of two consecutive packets, i.e. (N, N, N+1); the second mode is an interleaving mode of three or more consecutive packets, i.e. (N, N, N+1, N+2, ..., N+k); the third mode is an odd-even separated interleaving mode, i.e. (N, N, N+2, N+4, ..., N+2k); N is a natural number, indicating a data packet sequence number; k is a natural number greater than or equal to 2, set by the system or user; When the environmental interference is small and scattered, the first mode is adopted; when the environmental interference is large, the second mode or the third mode is adopted.

[0016] Further, the data packet distribution configuration indicated by the ID information includes: interleaving mode configuration between data packets of different Channel types, The corresponding interleaving mode is configured as follows: data packets of different Channel types are sent alternately in sequence. According to the set number of data packet retransmissions, the mode is expressed as (A1, A2,…,An, A1, A2,…,An,…); where n is a natural number, which is the total number of Channel types.

[0017] Further, the data packet distribution configuration indicated by the ID information includes: a mixed interleaving mode configuration, The corresponding interleaving mode is configured as follows: data packets of different channel types are sent alternately in sequence, and at the same time, the following data packet occupies part of the sending space of the previous data packet to send the following data packet in advance in the previous round. According to the set number of data packet retransmissions, the mode is expressed as (A1, A2,…,An, A1, A2,…,An,…A1+1, A2+1,…An+1,…,A1+m, A2+m,…,An+m); Among them, n and m are natural numbers, n is the total number of Channel types, m is the number of data packet sequences that are located later but sent in advance in the previous round, An represents the sequence number of the data packet in this round, and An+m represents the sequence number of the data packet that is located later but sent in advance in this round.

[0018] Furthermore, the ID information of the schedule layout information Schedule Map also configures the anchor point information of the data packet; for multiple data packets belonging to different channel types but need to be played synchronously, a common anchor point is configured so that the related data packets of different audio channels Channel can be played synchronously; For a sequence of data packets sent between two beacons, the anchor points of data packets belonging to different audio channel types but with the same sequence number in the data packet sequence are the same, and the time difference between adjacent anchor points is equal to the frame playback duration configured in the subdirectory; the playback time of data packets with the same sequence number is equal to the anchor point configured for the data packet plus the playback time in the aforementioned audio information Audio Information.

[0019] Furthermore, the audio data is encrypted data. In this case, a broadcast code is configured for the audio data. The audio source device is configured to: after sending a beacon configured with audio broadcast information, encrypt the audio data after calculating the key through the aforementioned broadcast code to obtain the audio data in ciphertext form, and send the audio data packet in ciphertext form; and when the time point of the next beacon Beacon arrives, send the beacon Beacon configured with audio broadcast information; The receiving device is configured to: obtain the aforementioned broadcast code when joining the network, and calculate the key through this code; after scanning the aforementioned beacon Beacon sent by the sound source device and parsing the relevant domain, receive the continuous audio data packets following this beacon Beacon according to the audio channel Channel type configured by the local device, and the audio data packets are in ciphertext form, and use the aforementioned key to decrypt the received audio data.

[0020] The present invention also provides a wireless audio transmission method based on WiFi, comprising the following steps: The sound source device Source locally creates a wireless network basic service set BSS consisting of itself and multiple receiving devices Sink, and the sound source device Source and the receiving device Sink are provided with WiFi communication modules; When audio needs to be played, the audio source device Source obtains the audio data to be played and forwards it to the Sink device in the BSS network; the audio source device Source processes the obtained audio data to encapsulate the audio data of different audio channels Channel in different data packets and sends them in sequence. The sent data packets do not require the Sink device to reply with an ACK message; The receiving device Sink connected to the BSS network receives the audio data packets corresponding to one or more audio channels Channel configured by itself from the data packets sent by the audio source device according to its own configuration information, and then plays the received audio data.

[0021] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art, as an example: the wireless audio system provided by the present invention includes a sound source device Source and a receiving device Sink, and another wireless network BSS (different from AP) is created locally through the sound source device Source. The sound source device Source acts as a transmitting end in the BSS network, and can process the acquired audio data to encapsulate the audio data of different audio channels Channel in different data packets Packets and send them in sequence; the receiving device Sink acts as a receiving end in the BSS network, and can receive data packets corresponding to one or more audio channels Channel configured by itself from the data packets sent by the sound source device according to its own configuration information, and then play the audio data locally. The present invention provides a wireless audio networking and communication solution based on WiFi by extending the existing WiFi technology, which makes full use of the high bandwidth characteristics of WiFi, can realize high-fidelity, multi-channel audio data transmission, and has the flexibility similar to Bluetooth audio technology. On the one hand, the audio data sent by the audio source device Source does not need the receiving device Sink to confirm whether it is received, and the Sink device does not need to reply ACK, which is beneficial to its power saving and extended use time. It is especially suitable for a network system composed of audio source devices Source that are not sensitive to power consumption (such as TVs and desktop computers that are usually powered by a fixed power supply) and audio playback devices that are sensitive to power consumption (such as wireless headphones and wireless speaker amplifiers powered by batteries). On the other hand, multi-channel data is encapsulated in different packets and sent. The receiving device Sink only needs to selectively receive certain packets, not all packets, which can further save power consumption.

[0022] Furthermore, the WiFi beacon signal is expanded, and a new type of information elements is configured in the beacon, which is used as an entry point to construct a typical implementation process of the present invention, including service discovery, MAC (Medium Access Control) layer scheduling, data transmission reliability, data security and other functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention provides a communication network topology structure 1.

[0024] Figure 2 The present invention provides a second communication network topology.

[0025] Figure 3This is a structural diagram of the Information Element of the audio broadcast AudioCast provided by the present invention.

[0026] Figure 4 This is a data organization structure diagram of the Audio Information provided by the present invention.

[0027] Figure 5 The data organization structure diagram of the corresponding Audio Information when the sound source device provided by the present invention sends left and right two-channel audio stream data in the MP3 codec type.

[0028] Figure 6 When the audio source device provided by the present invention sends audio stream data of 5 audio channels in Dolby type, the corresponding Audio Information data organization structure diagram is shown.

[0029] Figure 7 The data organization structure diagram of the corresponding Audio Information when the public place provided by the present invention broadcasts 3 channels (corresponding to 3 sub-directories) of television programs; wherein each channel includes data of 2 left and right channels.

[0030] Figure 8 for Figure 7 The corresponding Audio Information field data format diagram.

[0031] Fig. 9 This is a data format diagram of the Schedule Map field in the Information Element structure provided by the present invention.

[0032] Fig.10 The ID information provided by the present invention indicates a data packet timing diagram corresponding to the distribution time of the data packet and the number of transmission times (taking Q=3 as an example).

[0033] Fig.11 A timing diagram of data packets of the same Channel type provided by the present invention when the first mode (N, N, N+1) is adopted for interleaving.

[0034] Fig.12 A timing diagram of data packets of the same Channel type provided by the present invention when the second mode (N, N, N+1, N+2) is adopted for interleaving.

[0035] Fig.13 A timing diagram of data packets of the same Channel type provided by the present invention when the third mode (N, N, N+2, N+4) is adopted for interleaving.

[0036] Fig.14 This is a data organization structure diagram corresponding to the subdirectories in the scenario of left and right channels provided by the present invention.

[0037] Fig.15 for Fig.14 The packet timing diagram when two Channel type packets are interleaved is provided.

[0038] Fig.16 Based on Fig.14 The following is a timing diagram of the data packets of the two Channel types provided, using the mixed interleaving mode.

[0039] Fig.17 The basis provided by the present invention Figure 5 In the scenario of left and right channels, the data packet timing diagram of the dual-channel synchronous playback of related audio packets is provided.

[0040] Fig.18 This is a data processing flow chart of the sound source device provided by the present invention.

[0041] Fig.19 A data processing flow chart of the receiving device provided by the present invention. DETAILED DESCRIPTION

[0042] The following is a further detailed description of the WiFi-based wireless audio system and wireless audio transmission method disclosed in the present invention in conjunction with the accompanying drawings and specific embodiments. It should be noted that the technology (including methods and devices) known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the above-mentioned known technology is regarded as part of the specification. At the same time, other examples of exemplary embodiments may have different values. The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions that the invention can be implemented. In the description of the embodiments of the present application, " / " means or, and "and / or" is used to describe the association relationship of the associated objects, indicating that there can be three relationships, for example, "A and / or B" means: A and B exist alone, B exists alone, and A and B exist at the same time. In the description of the embodiments of the present application, "multiple" refers to two or more.

[0043] Technical term explanation: 1) AP (full name Access Point): wireless access point, also known as WiFi access point, wireless access node. AP is a device in a wireless local area network (WLAN). It acts as an infrastructure device for the wireless network and is used to connect the client terminal Station (also known as STA) to the network. The WiFi access point AP has the function of transmitting and receiving wireless signals and is connected to the wired network to transmit wireless data to the Internet. Multiple client terminals Station can access the WiFi access point AP. The WiFi access point AP and each client terminal Station are connected by WiFi. The WLAN link can be any physical layer protocol defined by 802.11, and can communicate in both directions.

[0044] 2) Wireless network BSS (Basic Service Set): refers to the basic service set of the wireless network. In a wireless local area network, the basic service set BSS is a network structure consisting of a single access point AP and multiple wireless mobile stations STA; each BSS has an identifier, called the basic service set identifier BSSID, which is used to distinguish different networks. Mobile stations STA within the BSS can communicate with each other directly without forwarding data through the AP. When a mobile station STA wants to join a BSS, it will go through an association process, which usually includes a scanning process to discover the BSS network and establish an association with the access point AP, and then data transmission can begin.

[0045] 3) ACK (full name Acknowledgement): refers to the confirmation signal, which is a positive feedback. The receiver replies to the sender after receiving the data. The corresponding one is NACK (full name Negative Acknowledgement), which is a negative feedback. The receiver notifies the sender only when it has not received the data.

[0046] 4) Beacon: WiFi Beacon provides the "heartbeat" of the wireless LAN, so that connected devices can establish and maintain synchronous communication. In the STA working mode of WIFI, after the access point AP is connected to the workstation STA, it will periodically send Beacon frames. Specifically, the Beacon frame is a management frame (Management Frame) that is periodically sent by the access point AP at a certain time interval to notify the workstation STA within its coverage area about the existence of the network and some network parameters. At present, the network parameters involved in the Beacon mainly include the network name SSID, the supported data transmission rate, encryption method, etc. Example

[0047] This embodiment provides a WiFi-based wireless audio system, including a sound source device Source and multiple receiving devices Sink. The sound source device Source and the receiving device Sink are provided with WiFi communication modules. The sound source device Source is used to obtain audio data resources from the network, and the audio data resources are audio stream data.

[0048] The audio source device Source is configured to: locally create a wireless network basic service set BSS consisting of itself and the aforementioned receiving device Sink; and, as a transmitter in the aforementioned BSS network, forward the acquired audio data to the Sink device in the BSS network, wherein the acquired audio data is processed to encapsulate the audio data of different audio channels Channel in different data packets Packets and send them in sequence, and the sent data packets do not require the Sink device to reply with an ACK message.

[0049] The receiving device Sink, as a receiving end in the BSS network, is configured to: receive data packets corresponding to one or more audio channels Channel configured by itself from the data packets sent by the sound source device according to its own configuration information; and locally play the audio data in the received data packets.

[0050] Specifically, according to the functions configured by the audio source device Source itself, this embodiment provides two typical network topologies, see Figure 1 and 2 shown.

[0051] in, Figure 1 The network system in the example includes a WiFi access point AP, and the audio source device Source is connected to the Internet through the WiFi access point AP to obtain streaming media resources. For example, a home TV is connected to a server on the network through the AP to obtain streaming media resources. Then, the audio source device creates another wireless network BSS (different from the AP) locally, and forwards the audio data to the Sink device in the newly created network. At this time, the audio source device will also process the audio data accordingly, and the processing may specifically include: extracting audio data of different audio channels Channel from the acquired audio data; compressing and encoding the audio data of different audio channels Channel; and encapsulating the compressed and encoded data of different audio channels Channel in different data packets and sending them in sequence.

[0052] For the receiving devices Sink in the network, they can receive only the data of one or several audio channels Channel for local playback according to their actual configuration. For example, in a home theater, multiple audio systems, as receiving devices Sink, can receive only the single channel data of audio channels such as Front Left, Front Right, Front Center, Back Left, and Back Right.

[0053] See also Figure 2 As shown in the figure, the audio source device Source may be an AP itself, or it may have the ability to connect to the network - for example, it is connected to a wired network, or it may be able to connect to a wired radio broadcast network (also known as a broadcast program transmission and distribution network) to obtain streaming media resources - for example, the audio source device Source is a TV connected to streaming media resources through a wired radio station. In this application scenario, the audio source device Source only needs to create a wireless network BSS, and no longer needs to connect to the Internet through an AP to obtain streaming media resources. Other configurations are the same as above.

[0054] In one implementation of this embodiment, corresponding to multiple audio channels Channel, the receiving device Sink can be multiple audio playback devices arranged in different locations (such as different rooms), and each receiving device Sink receives the data packets of its own audio channel and then performs local synchronous playback.

[0055] In another implementation of this embodiment, corresponding to multiple audio channels Channel, the receiving device Sink can also be the same audio playback device. In this case, the receiving device Sink can simultaneously receive data packets of multiple audio channels, mix the multiple data channels locally, and then play them synchronously.

[0056] As an example but not limitation of a typical manner, the audio channels may include at least two of a left channel Left, a right channel Right, a center channel Center, a left front channel Front Left, a right front channel Front Right, a front center channel Front Center, a back center channel Back Center, a left rear channel Back Left, and a right rear channel Back Right.

[0057] In order to realize multi-channel, high-fidelity, and low-power data transmission and reception between the sound source device Source and the receiving device Sink in the BSS network, the present invention extends the WiFi beacon Beacon and configures a new type of information elements (Information Elements) in the beacon Beacon. This is used as an entry point to construct a typical implementation process of the present invention, including service discovery, MAC layer scheduling, data transmission reliability, data security and other functions.

[0058] According to the existing WiFi technology, the information element structure in the WiFi protocol is as follows: Figure 3 As shown, the Element ID bit is used to indicate the identifier of different types of elements, which occupies one byte, that is, it can indicate up to 256 types. There are many reserved bits in the current WiFi protocol that are not used. The Element ID bit is followed by the Length bit, which occupies one byte and is used to indicate that the subsequent Payload (payload) can be up to 256 bytes long.

[0059] Based on the above-mentioned prior art, the present invention adds a new type of information element Information Element in the beacon Beacon. The information element is an information element related to the audio broadcast function. As an example but not a limitation, it can be defined as: Element ID -> "AudioCast (audio broadcast)".

[0060] Then, using the Payload space (which can be up to 256 bytes), the present invention further divides the aforementioned information element AudioCast. Figure 3 As shown, the information of AudioCast is divided into two parts: Schedule Map and Audio Information. The Schedule Map is mainly used to indicate the time, carrier frequency band and channel of each audio channel Channel, and the Audio Information is mainly used to indicate the currently transmitted audio information, that is, the relevant information of the currently transmitted audio data.

[0061] At this time, the audio source device Source, as the transmitter in the aforementioned BSS network, is configured to: broadcast a beacon Beacon configured with audio broadcast information, that is, the broadcast beacon Beacon is configured with the aforementioned information element AudioCast (audio broadcast), and the AudioCast information element includes the scheduling layout information Schedule Map and audio information Audio Information of this audio broadcast; and, after the aforementioned beacon Beacon is sent, send an audio data packet.

[0062] The receiving device Sink, as the receiving end in the aforementioned BSS network, is configured to: perform a scanning operation to obtain the beacon Beacon sent by the aforementioned audio source device Source, and parse the relevant domains of the beacon Beacon; according to the AudioCast information element configured in the beacon Beacon, according to the audio channel Channel type configured by the local device, selectively receive the continuous audio data packets following the aforementioned beacon Beacon; and, calculate the local playback time of the audio data packet, and play the corresponding audio data packet after the time point arrives.

[0063] See also Figure 4 As shown, in this embodiment, the audio information Audio Information is preferably organized in a hierarchical structured data. As an example of a typical method, for example, the top layer is set as the Audio Information general directory. The audio information general directory may be provided with subdirectories, and the subdirectories may be one or more. Each subdirectory is provided with a channel type, i.e., a Channel type, which may include one or more Channel types.

[0064] Preferably, the following parameter items can be configured in the Audio Information general directory: playback time information, which is used to indicate how long the device needs to wait after the physical layer receives the audio data packet before playing the audio data in the data packet for synchronization of playback data of different audio channels; and sub-directory quantity information, which is used to indicate the number of sub-directories included in this directory.

[0065] Preferably, the following parameter items may be configured in the subdirectory: channel quantity information, used to indicate the number of audio channels; and multimedia digital signal codec Codec type information, used to indicate the type of multimedia digital signal codec Codec; and sampling frequency information, used to indicate the sampling rate of the audio; and frame playback duration information, used to indicate the duration of each frame time sent by the air interface when it is played; and the number of bytes per frame, used to indicate the actual length of each frame; and audio Audio type, used to indicate the type of audio; and language information, used to indicate the language type of audio data.

[0066] As an example but not a limitation, for example, according to the left and right channels of stereo, the number of channels configured is 2, see Figure 5 As shown; for the home theater scenario, the number of configured channels is 5, see Figure 6 The Codec type can be MP3, SBC, AAC, SBC, LC3, etc. The sampling frequency is set according to the sampling rate information of the audio stream, such as 48 kHz, 96 kHz, etc. The frame playback duration indicates the duration of each frame sent by the air interface when it is played. For example, it can be set to 5ms, 7.5ms, 10ms, etc. as needed. The number of bytes per frame indicates the actual length of each frame, such as Figure 5 and Figure 6 The number of bytes per frame in the audio is 128 bytes. The audio type may be music, broadcast, television program, telephone conference, etc. The language type may be Chinese, English, Japanese or other languages.

[0067] Preferably, the channel type may be configured with the following parameter items: channel ID, which corresponds to the configuration content of the audio channel Channel in the aforementioned scheduling layout information Schedule Map - as an example but not a limitation, the channel ID may be 1, 2, 3, ..., which corresponds to the corresponding content in Schedule Map; and channel name - for example, it may be left channel, right channel, left front channel Front Left, right front channel Front Right, front center channel Front Center, left rear channel Back Left, and right rear channel Back Right, etc.

[0068] By way of example and not limitation, Figure 5The example audio information Audio Information is configured as follows: the audio source device currently sends left and right channel audio streams in MP3 codec type, with a sampling frequency of 48 kHz. Each data packet in the air interface contains 10ms of audio data with a length of 128 bytes. If the receiving device Sink is two independent speakers, it can receive the respective channel data (left channel or right channel) for playback. The playback time is 45ms, that is, after receiving the current audio data packet, the speaker waits 45ms before starting to play the current audio data packet to ensure the synchronous playback of the aforementioned left and right channel data. The Audio type is music, and the language type of the audio data is Chinese.

[0069] Figure 6 The audio information of the example is configured as follows: the audio source device sends the data of 5 audio channels Channel in Dolby type, namely Right, Left, Center, Back Right and Back Left. The receiving device Sink can be 5 speakers in different locations (such as different rooms) or a single speaker (which can receive 5 channels of data at the same time and then mix multiple channels of audio locally); the playback time is 60ms, that is, after receiving the current audio data packet, the speaker waits 60ms before starting to play the current audio data packet to ensure the synchronization of left and right channel data. Figure 5 The explanation in will not be repeated here.

[0070] It should be noted that Figure 5 and Figure 6 The example shows a scenario in which a subdirectory is set under an Audio Information directory. However, those skilled in the art should know that, depending on the actual application scenario, an Audio Information directory can be set with multiple subdirectories. For example, there is the following application scenario: broadcasting TV programs from multiple channels in a public place - for example, if TV programs from three channels need to be broadcast at the same time, the number of subdirectories can be configured to 3, and each subdirectory can include data from the left and right channels. At this time, the sorting sequence of the Channel type ID becomes 1, 2, 3, 4, 5, and 6, which correspond to the corresponding fields in the Schedule Map, so that the receiving device Sink can correctly find the sending time point and channel position of the sound source device Source. See Figure 7 As shown, the data organization structure diagram of the audio information Audio Information in the aforementioned scenario is illustrated.

[0071] The present invention utilizes the WiFi transmission characteristics and proposes the above-mentioned hierarchical structured audio information AudioInformation structure, which has good scalability and can be applicable to audio broadcasting needs in various application scenarios.

[0072] In order to configure the hierarchical structured data into the flat Audio Information field of the data packet, this embodiment preferably uses Extended Backus-Naur Form (EBNF) to express it. The specific expression is as follows: Audio_Information = "AI Header" ["Subdirectory" ["Channel Type"]+]+ .

[0073] In the formula, AI header indicates the total directory of Audio Information, []+ indicates to expand the contents in [] once or multiple times, and Figure 4 The meaning of 1..* in the UML class diagram in the example is similar. Specifically, ["Channel type"]+ means expanding "Channel type" multiple times (corresponding to multiple Channel types, for example, for the left and right channels, the Channel type is expanded twice); ["subdirectory" ["Channel type"]+]+ means expanding "subdirectory" ["Channel type"] multiple times, for example Figure 7 Expand the 3 subdirectories in "Subdirectory" ["Channel Type"] 3 times.

[0074] Based on the above EBNF expression, Figure 7 For the corresponding Audio Information field data format diagram, see Figure 8 shown.

[0075] In this embodiment, the scheduling layout information Schedule Map includes multiple "ID information", see Fig. 9 Each "ID information" is associated with a channel ID under the Channel type in the audio information Audio Information, and the ID information is used to indicate the distribution of data packets during two beacon transmissions, as well as the number of retransmissions and the order of data packets.

[0076] For multiple data packets belonging to the same audio channel Channel type, each data packet is configured to be sent Q times to increase the probability of receiving the packet by the receiving device Sink, where Q is a natural number greater than or equal to 2. At this time, the receiving device Sink is configured to: after a data packet is successfully received, determine whether there is a retransmission data packet behind the data packet, and if it is determined that there is a retransmission data packet, do not receive the retransmission data packet.

[0077] Combine the following Figures 10 to 16 Describes in detail the transmission scheduling policy configuration of the data packet.

[0078] See also Fig.10 As shown in the figure, between two beacons, there are N packets to be sent under a certain audio channel type. Here, Q=3 is configured, that is, each packet is configured to be sent 3 times to increase the success probability of the receiving device. For the receiving device Sink, when it accurately receives a packet, it does not need to continue to receive the retransmitted packets (if there are any packets). It should be noted that the ratio of the packets in the figure is for example rather than limitation. In specific implementation, it can be configured according to the actual packet transmission parameters.

[0079] For multiple data packets of the same Channel type, considering environmental interference, in order to improve the reliability of data packet transmission, different strategies can also be configured to ensure the success probability of the receiving device Sink receiving the packet (receiving the data packet). Furthermore, in actual transmission, there may be multiple Channel type data packets that need to be transmitted. In order to improve the reliability of data transmission, different strategies also need to be configured to ensure the success probability of the receiving device Sink receiving the packet.

[0080] This embodiment configures different data packet interleaving strategies through the distribution indicated by the ID information, preferably, divided into the following three situations: the first one, the interleaving strategy between packets of the same Channel type; the second one, the interleaving strategy between packets of different Channel types; the third one, the mixed interleaving strategy of the above two. Correspondingly, the data packet distribution configuration indicated by the ID information includes: the interleaving mode configuration between data packets of the same Channel type, the interleaving mode configuration between data packets of different Channel types, and the mixed interleaving mode configuration.

[0081] Specifically, for the interleaving between data packets of the same Channel type, the corresponding interleaving mode is configured to include a first mode, a second mode and a third mode.

[0082] The first mode is an interleaving mode of two consecutive packets. Fig.11As shown in the figure, it is a data packet timing diagram when two consecutive packets are interleaved. The consecutive data packets 1 and 2 are interleaved, which are expressed as (1, 2); data packets 2 and 3 are interleaved, which are expressed as (2, 3); data packets 3 and 4 are interleaved, which are expressed as (3, 4); and so on, data packets N and N+1 are interleaved, which are expressed as (N, N+1). The above interleaving pattern can be summarized as the expression (N, N, N+1), where N is a natural number, representing the data packet sequence number.

[0083] The first mode is suitable for situations where environmental interference is small and scattered. Fig.11 The time period x below the data packet indicates environmental interference.

[0084] The second mode is an interleaving mode of three or more consecutive packets. Fig.12 As shown in the figure, a data packet timing diagram is illustrated when three consecutive packets are interleaved. The consecutive data packets 1, 2 and 3 are interleaved, which are expressed as (1, 2, 3); data packets 2, 3 and 4 are interleaved, which are expressed as (2, 3, 4); data packets 3, 4 and 5 are interleaved, which are expressed as (3, 4, 5), and so on. Data packet N, data packet N+1 and data packet N+2 are interleaved, which are expressed as (N, N+1, N+2). The above interleaving pattern can be summarized as the expression (N, N, N+1, N+2), where N is a natural number, representing the data packet sequence number.

[0085] For the interleaving pattern of more than three consecutive packets, the corresponding expression is (N, N, N+1, N+2, ..., N+k), which means k+1 consecutive packets are interleaved, where N is a natural number, indicating the data packet sequence number; k is a natural number greater than or equal to 2, indicating the subsequent k packets, which can be set by the system or the user. When k=2, it is (N, N, N+1, N+2).

[0086] The third mode is an odd-even separated interleaving mode, see Fig.13 As shown, an example of a data packet timing diagram when three odd-numbered consecutive packets are interleaved separately is shown. Three odd-numbered consecutive data packets 1, 3 and 5 are interleaved, expressed as (1, 3, 5); three even-numbered consecutive data packets 2, 4 and 6 are interleaved, expressed as (2, 4, 6); three odd-numbered consecutive data packets 3, 5 and 7 are interleaved, expressed as (3, 5, 7), and so on, data packet N, data packet N+1 and data packet N+2 are interleaved, expressed as (N, N+1, N+2). The above interleaving pattern can be summarized as the expression (N, N, N+2, N+4), where N is a natural number, representing the data packet sequence number.

[0087] For the odd-even separated interleaving mode of more than three consecutive packets, the corresponding expression is (N, N, N+2, N+4, ..., N+2k), which means the odd-even separated interleaving of k+1 consecutive packets, where N is a natural number, indicating the data packet sequence number; k is a natural number greater than or equal to 2, which can be set by the system or user. When k=2, it is (N, N, N+2, N+4).

[0088] When the environmental interference is relatively large, the second mode or the third mode may be used to improve the reliability of data packet transmission.

[0089] For the interleaving of data packets of different Channel types, preferably, the corresponding interleaving mode is configured as follows: data packets of different Channel types are sent alternately in sequence, and according to the set number of data packet retransmissions, the mode is expressed as (A1, A2,…,An, A1, A2,…,An,…); wherein n is a natural number, which is the sum of the number of Channel types. If i represents the Channel sequence number, then i=1, 2,…, n.

[0090] By way of example and not limitation, for example Fig.14 The left and right channels are set in a subdirectory as shown, and the data of different channels are sent alternately in sequence. Fig.15 As shown in the figure, packets of different colors represent packets of different channel types (left channel or right channel). Here, Q=2 is configured, that is, each packet is sent twice. n is the total number of channels, Fig.15 The system shown includes a subdirectory, under which left and right channels are set, that is, n=2 (at this time, i=1, 2), and the corresponding interleaving pattern expression is (A1, A2, A1, A2). When the sound source device sends a data packet, it first sends the left channel data packet 1 (A1), then sends the right channel data packet 1 (A2), resends the left channel data packet 1 (A1), and then resends the right channel data packet 1 (A2); then, entering the next round, first sends the left channel data packet 2 (A1), then sends the right channel data packet 2 (A2), resends the left channel data packet 2 (A1), and then resends the right channel data packet 2 (A2); and so on, until the N data packets of the left and right channels are sent (sent 2 times).

[0091] By analogy, when the system includes 2 sub-directories and left and right channels are set in each sub-directory, then n=2+2=4 (at this time, i=1, 2, 3, 4), when Q=2, the corresponding interleaving pattern expression is (A1, A2, A3, A4, A1, A2, A3, A4).

[0092] For mixed interleaving, preferably, the corresponding interleaving mode is configured as follows: data packets of different Channel types are sent alternately in sequence, and at the same time, the following data packets occupy part of the sending space of the previous data packet to send the following data packet in advance in the previous round. According to the set number of data packet retransmissions, the mode is expressed as (A1, A2,…,An, A1,A2,…,An,…A1+1, A2+1,…An+1,…, A1+m, A2+m,…, An+m). Among them, n and m are natural numbers, n is the sum of the number of Channel types, m is the number of data packet sequences located at the back but sent in advance in the previous round, An represents the sequence number of the data packet in this round, and An+m represents the sequence number of the data packet located at the back but sent in advance in this round, that is, the data packet Ai+m (i=1, 2,…, n, i represents the Channel sequence number) located at the back is sent in advance in the previous round.

[0093] By way of example and not limitation, for example Fig.14 The scene of setting left and right channels in a subdirectory shown in the figure, the data including the timing diagram when using the mixed interleaving mode is shown in Fig.16 As shown in the figure, packets of different colors represent packets of different channel types (left channel or right channel). Here, Q=3 is configured, that is, each packet is sent 3 times. n is the total number of channels, Fig.16 The system shown includes a subdirectory, in which the left and right channels are set, that is, n=2 (in this case, i=1, 2); m is the number of data packet sequences that are located at the back but sent in advance in the previous round, Fig.16Here, m=1, that is, the data packet Ai+1 (i=1, 2) located at the back needs to be sent in the previous round in advance. The corresponding interleaving pattern expression is (A1, A2, A1, A2, A1+1, A2+1). When the audio source device sends data packets, it first sends left channel data packet 1 (A1), then sends right channel data packet 1 (A2), resends left channel data packet 1 (A1), then resends right channel data packet 1 (A2), sends left channel data packet 2 (A1+1, that is, the next left channel data packet 2 behind left channel data packet 1 is sent in advance), and then sends right channel data packet 2 (A2+1, that is, the next right channel data packet 2 behind right channel data packet 1 is sent in advance). The left channel data packet 2 and right channel data packet 2 sent in advance occupy the sending space originally configured for the third retransmission of left channel data packet 1 and right channel data packet 1 (that is, left channel data packet 1 and right channel data packet 1 are not retransmitted for the third time); then, in the next round, the left channel data packet 2 (A1) is sent first, then the right channel data packet 1 (A2+1) is sent. Right channel data packet 2 (A2), retransmit left channel data packet 2 (A1), retransmit right channel data packet 2 (A2), send left channel data packet 3 (A1+1, that is, the next left channel data packet 3 behind left channel data packet 2 is sent in advance), and then send right channel data packet 3 (A2+1, that is, the next right channel data packet 3 behind right channel data packet 2 is sent in advance). The left channel data packet 3 and right channel data packet 3 sent in advance occupy the retransmission space originally configured for left channel data packet 2 and right channel data packet 2 (since left channel data packet 2 and right channel data packet 2 were sent in advance once in the previous round, left channel data packet 2 and right channel data packet 2 still correspond to 3 transmissions); and so on, until the N data packets of the left and right channels are sent (sent 3 times).

[0094] Through the above-mentioned hybrid interleaving, multiple transmissions of a data packet can be separated into multiple time periods, thereby minimizing the multiple transmissions of a data packet in a dense time period. Such a strategy can improve the probability of successful packet reception by the receiving device: because if a data packet is sent multiple times in a dense time period, some strong interference that appears in a short period of time may knock them all out; by sending the subsequent data packets in advance and dispersing the multiple transmissions of the data packets in different time periods, the probability of multiple transmissions of a data packet being completely knocked out can be reduced, thereby improving the probability of success.

[0095] In order to ensure that the data packets of each audio channel Channel are played synchronously, they must have a common anchor point. In the present invention, this anchor point is obtained in the ID information. That is to say, the anchor point information of the data packet is also configured in the ID information of the scheduling layout information Schedule Map; for multiple data packets belonging to different channel Channel types but need to be played synchronously, a common anchor point is configured so that the related data packets of different audio channels Channel can be played synchronously.

[0096] For a sequence of data packets sent between two beacons, the anchor points of data packets with different audio channel types but the same sequence number in the sequence are the same, and the time difference between adjacent anchor points is equal to the frame playback duration configured in the subdirectory; the playback time of data packets with the same sequence number is equal to the anchor point configured for the data packet plus the playback time in the aforementioned Audio Information.

[0097] For example, see Fig.17 As shown in the figure, for data packets 1, 2, 3, ..., N in the data packet sequence, there is an anchor point. The time difference between adjacent anchor points is equal to the frame playback duration. The anchor points of data packets with different channel types and the same sequence number are the same. Moreover, the playback time of packets with the same sequence number is equal to the anchor point plus the playback time configured in the Audio Information. Figure 5 In the dual-channel example, the left and right channel data packets with sequence number 1 are played simultaneously at the time points indicated by the arrows.

[0098] In this embodiment, considering data security, the audio data may also be encrypted data.

[0099] Existing WiFi usually adopts WPA / WPA2 / WPA3 encryption mode, or open non-encryption mode. Current audio applications do not require particularly strong encryption, because strong encryption has certain requirements on the computing power and power consumption of the device. Accordingly, the present invention configures a simple data encryption method based on the original WiFi encryption, which does not require high computing power of the device and is easy to implement.

[0100] Specifically, a broadcast code is configured for the audio stream. The receiving device connected to the network can obtain this code through the administrator (or a specific sign in a public place or conference hall). The corresponding key can be calculated from this code (the broadcast code and the key have a corresponding relationship, and the corresponding key can be calculated from the broadcast code). The audio source device uses the key to encrypt the audio stream and then sends it out. The receiving device calculates the key from this code and uses the key to decrypt the received audio stream.

[0101] For details, see Fig.18 As shown, the audio source device is configured to: after sending a beacon configured with audio broadcast information, encrypt the audio data after calculating the key through the aforementioned broadcast code, obtain the audio data in ciphertext form, and send the audio data packet in ciphertext form; and, when the time point of the next beacon Beacon arrives, send the beacon Beacon configured with audio broadcast information.

[0102] See also Fig.19 As shown, the receiving device is configured to: obtain the aforementioned broadcast code when joining the network, and calculate the key through this code; after scanning the aforementioned beacon Beacon sent by the sound source device and parsing the relevant domain, according to the audio channel Channel type configured by the local device, receive the continuous audio data packets following this beacon Beacon, the audio data packets are in ciphertext form, and use the aforementioned key to decrypt the received audio data.

[0103] In this embodiment, the encryption algorithm is an XOR encryption algorithm based on an XOR operation rule.

[0104] XOR is a logical operation with simple operation rules. Specifically, for two binary bits, when the two bits are the same (both are 0 or both are 1), the XOR result is 0; when the two bits are different (one is 0 and the other is 1), the XOR result is 1. For example, 0 XOR 0 = 0, 0 XOR 1 = 1, 1 XOR 0 = 1, 1 XOR 1 = 0.

[0105] In XOR encryption, data plaintext (original information), key and data ciphertext are included. Decryption is the reverse process of encryption. For XOR operation, it has a special property, that is, A XOR B XOR B=A.

[0106] The data encryption process performed by the audio source device is as follows: according to the configured broadcast code Broadcast Code, the corresponding key, such as a one-byte key K, is obtained, and the plaintext data, such as a one-byte plaintext data M, is encrypted. The encrypted ciphertext C can be obtained by the formula C=M XOR K.

[0107] For example, assuming the plaintext M is 01010101 in binary and the key K is 10101010, then the ciphertext C = 01010101 XOR 10101010 = 11111111.

[0108] The decryption process performed by the receiving device is as follows: receiving the ciphertext C, obtaining the corresponding key according to the broadcast code obtained when joining the network - for example, a one-byte key K, and restoring the plaintext through the formula M=C XOR K - that is, obtaining a one-byte plaintext data M.

[0109] As an example, for the ciphertext 11111111 and the key 10101010 obtained above, the plaintext M=11111111XOR 10101010=01010101, which just restores the original plaintext.

[0110] In another embodiment of the present invention, a WiFi-based wireless audio transmission method is provided for multi-channel audio data transmission.

[0111] The method comprises the following steps: S100, the sound source device Source locally creates a wireless network basic service set BSS consisting of itself and multiple receiving devices Sink, and the sound source device Source and the receiving device Sink are provided with WiFi communication modules.

[0112] S200, when audio needs to be played, the audio source device Source obtains the audio data to be played and forwards it to the Sink device in the BSS network; wherein, the audio source device Source processes the obtained audio data to encapsulate the audio data of different audio channels Channel in different data packets Packets and sends them in sequence, and the sent data packets do not require the Sink device to reply with an ACK message.

[0113] S300, a receiving device Sink connected to the BSS network receives, according to its own configuration information, an audio data packet corresponding to one or more audio channels Channel configured by itself from the data packet sent by the audio source device, and plays the received audio data.

[0114] Specifically, the audio source device Source, as the transmitter in the aforementioned BSS network, is configured to perform the following steps: broadcast a beacon Beacon configured with audio broadcast information, at this time, a new information element type audio broadcast AudioCast is configured in the beacon Beacon, and the audio broadcast AudioCast information element includes the audio broadcast scheduling layout information Schedule Map and audio information Audio Information, the scheduling layout information Schedule Map is used to indicate the time, carrier frequency band and channel of each audio channel Channel, and the audio information AudioInformation is used to indicate the relevant information of the currently sent audio data; and, after the aforementioned beacon Beacon is sent, send an audio data packet.

[0115] The receiving device Sink, as the receiving end in the aforementioned BSS network, is configured to perform the following steps: perform a scanning operation to obtain the beacon Beacon sent by the aforementioned audio source device Source, and parse the relevant domains of the beacon Beacon; according to the audio broadcast AudioCast information element configured in the beacon Beacon, according to the audio channel Channel type configured by the local device, selectively receive the continuous audio data packets following the aforementioned beacon Beacon; and, calculate the local playback time of the audio data packet, and play the corresponding audio data packet after the time point arrives.

[0116] For other technical features, please refer to the description of the previous embodiment and will not be repeated here.

[0117] In the above description, the disclosure of the present invention is not intended to limit itself to these aspects. Rather, within the scope of the target protection of the present disclosure, the components can be selectively and operatively combined in any number. In addition, terms such as "include", "encompass" and "have" should be interpreted as inclusive or open by default, rather than exclusive or closed, unless they are explicitly defined to the contrary. All technical, scientific or other terms are consistent with the meanings understood by those skilled in the art, unless they are defined to the contrary. Common terms found in dictionaries should not be interpreted too idealistically or too impractically in the context of relevant technical documents, unless the present disclosure explicitly defines them as such. Any changes and modifications made by a person of ordinary skill in the field of the present invention based on the above disclosure belong to the scope of protection of the claims.

Claims

1. A wireless audio system based on WiFi, characterized in that: It includes a sound source device Source and a receiving device Sink, wherein the sound source device Source and the receiving device Sink are provided with a WiFi communication module, and the sound source device Source is used to obtain audio data resources from the network; The audio source device Source is configured to: locally create a wireless network basic service set BSS consisting of itself and the aforementioned receiving device Sink; and, as a transmitter in the aforementioned BSS network, forward the acquired audio data to the Sink device in the BSS network, wherein the acquired audio data is processed to encapsulate the audio data of different audio channels Channel in different data packets and send them in sequence, and the sent data packets do not require the Sink device to reply with an ACK message; The receiving device Sink, as a receiving end in the BSS network, is configured to: receive data packets corresponding to one or more audio channels Channel configured by itself from the data packets sent by the sound source device according to its own configuration information; and locally play the audio data in the received data packets.

2. The system according to claim 1, characterized in that After the audio source device Source establishes a communication link with the WiFi access point AP, it connects to the network through the AP to obtain audio data resources; or, The audio source device Source itself is a WiFi access point AP, which can connect to the network to obtain audio data resources; or, The audio source device Source itself is configured with a network connection function, and can connect to a wired network to obtain audio data resources or can connect to a wired radio broadcasting network to obtain audio data resources.

3. The system according to claim 1, characterized in that The processing of the acquired audio data by the audio source device Source includes: Extract audio data of different audio channels from the acquired audio data; Compress and encode the audio data of different audio channels; The compressed encoded data of different audio channels are encapsulated in different data packets and sent sequentially.

4. The system according to any one of claims 1 to 3, characterized in that: Corresponding to multiple audio channels Channel, the receiving device Sink is a plurality of audio playing devices arranged at different positions, and each receiving device Sink receives the data packets of the respective audio channels and then performs local synchronous playback; Alternatively, corresponding to multiple audio channels Channel, the receiving device Sink is the same audio playback device. In this case, the receiving device Sink can simultaneously receive data packets of multiple audio channels, mix the multiple data channels locally, and then play them synchronously.

5. The system according to any one of claims 1 to 3, characterized in that: The audio source device Source, as a transmitter in the aforementioned BSS network, is configured to: broadcast a beacon Beacon configured with audio broadcast information. At this time, a new information element type audio broadcast is configured in the beacon Beacon. The audio broadcast information element includes scheduling layout information and audio information of the audio broadcast. The scheduling layout information is used to indicate the time, carrier frequency band and channel of each audio channel Channel. The audio information is used to indicate the relevant information of the currently transmitted audio data; And, after the aforementioned beacon Beacon is sent, an audio data packet is sent; The receiving device Sink, as the receiving end in the aforementioned BSS network, is configured to: perform a scanning operation to obtain the beacon Beacon sent by the aforementioned audio source device Source, and parse the relevant fields of the beacon Beacon; according to the audio broadcast information element configured in the beacon Beacon and the audio channel Channel type configured by the local device, selectively receive the continuous audio data packets following the aforementioned beacon Beacon; and, calculate the local playback time of the audio data packet, and play the corresponding audio data packet after the time point arrives.

6. The system according to claim 5, characterized in that The audio information Audio Information is organized in a hierarchical structured data format, with the top layer being the Audio Information general directory; the Audio Information general directory is provided with subdirectories, and there are one or more subdirectories; each subdirectory is provided with a channel Channel type, including one or more channel Channel types; The following parameter items are configured in the Audio Information general directory: playback time information, which is used to indicate how long the device needs to wait after receiving the audio data packet at the physical layer before playing the audio data in the data packet for synchronization of playback data of different audio channels; and sub-directory quantity information, which is used to indicate the number of sub-directories included in this directory; The subdirectory is configured with the following parameter items: Channel number information, used to indicate the number of audio channels; and Multimedia digital signal codec Codec type information, used to indicate the type of multimedia digital signal codec Codec; and, Sampling frequency information, used to indicate the audio sampling rate sample rate; and, Frame playback duration information, used to indicate the duration of each frame time sent by the air interface when it is played; And, the number of bytes per frame is used to indicate the actual length of each frame; and the audio type is used to indicate the type of audio; and the language information is used to indicate the language type of the audio data; The channel Channel type is configured with the following parameter items: channel ID, which corresponds to the configuration content of the audio channel Channel in the aforementioned scheduling layout information Schedule Map; and channel name.

7. The system according to claim 5, characterized in that The schedule map is configured with multiple ID information, each ID information is associated with a channel ID under the channel type in the audio information Audio Information, and the ID information is used to indicate the distribution of data packets during two beacon transmissions, as well as the number of retransmissions and the order of data packets.

8. The system according to claim 7, characterized in that For multiple data packets belonging to the same Channel type, each data packet is configured to be sent Q times to increase the probability of the receiving device Sink receiving the packet, where Q is a natural number greater than or equal to 2; at this time, the receiving device Sink is configured to: after a data packet is successfully received, determine whether there is a retransmitted data packet behind the data packet, and if it is determined that there is a retransmitted data packet, do not receive the retransmitted data packet.

9. The system according to claim 7, characterized in that The data packet distribution configuration indicated by the ID information includes: an interleaving mode configuration between data packets of the same Channel type, The corresponding interleaving mode is configured as: including a first mode, a second mode and a third mode; the first mode is an interleaving mode of two consecutive packets, that is, (N, N, N+1); the second mode is an interleaving mode of three or more consecutive packets, that is, (N, N, N+1, N+2, ..., N+k); the third mode is an odd-even separated interleaving mode, that is, (N, N, N+2, N+4, ..., N+2k); N is a natural number, indicating a data packet sequence number; k is a natural number greater than or equal to 2, set by the system or user; When the environmental interference is small and scattered, the first mode is adopted; when the environmental interference is large, the second mode or the third mode is adopted.

10. The system according to claim 7, characterized in that The data packet distribution configuration indicated by the ID information includes: interleaving mode configuration between data packets of different Channel types, The corresponding interleaving mode is configured as follows: data packets of different Channel types are sent alternately in sequence. According to the set number of data packet retransmissions, the mode is expressed as (A1, A2,…,An, A1, A2,…,An,…); where n is a natural number, which is the total number of Channel types.

11. The system according to claim 7, characterized in that The data packet distribution configuration indicated by the ID information includes: a mixed interleaving mode configuration, The corresponding interleaving mode is configured as follows: data packets of different Channel types are sent alternately in sequence, and at the same time, the following data packet occupies part of the sending space of the previous data packet so that the following data packet can be sent in advance in the previous round. According to the set number of data packet retransmissions, the mode is expressed as (A1, A2,…,An, A1, A2,…,An,…A1+1, A2+1,…An+1,…, A1+m, A2+m,…, An+m); wherein n and m are natural numbers, n is the total number of Channel types, m is the number of data packet sequences that are located at the back but sent in advance in the previous round, An represents the sequence number of the data packet in this round, and An+m represents the sequence number of the data packet that is located at the back but sent in advance in this round.

12. The system according to claim 5, characterized in that The ID information of the schedule layout information Schedule Map also configures the anchor point information of the data packet; for multiple data packets belonging to different channel types but need to be played synchronously, a common anchor point is configured so that the related data packets of different audio channels can be played synchronously; For a data packet sequence sent between two beacons, the data packets with the same sequence number but belonging to different audio channel types have the same anchor points, and the time difference between adjacent anchor points is equal to the frame playback duration configured in the subdirectory. The playing time of the data packets with the same sequence number is equal to the anchor point configured for the data packet plus the playing time in the aforementioned audio information Audio Information.

13. The system according to claim 5, characterized in that The audio data is encrypted data. At this time, a broadcast code is configured for the audio data. The audio source device is configured to: after sending a beacon configured with audio broadcast information, encrypt the audio data after calculating the key through the aforementioned broadcast code to obtain the audio data in ciphertext form, and send the audio data packet in ciphertext form; and when the time point of the next beacon Beacon arrives, send the beacon Beacon configured with audio broadcast information; The receiving device is configured to: obtain the aforementioned broadcast code when joining the network, and calculate the key through this code; after scanning the aforementioned beacon Beacon sent by the sound source device and parsing the relevant domain, receive the continuous audio data packets following this beacon Beacon according to the audio channel Channel type configured by the local device, and the audio data packets are in ciphertext form, and use the aforementioned key to decrypt the received audio data.

14. A wireless audio transmission method based on WiFi, characterized in that The steps include: The sound source device Source locally creates a wireless network basic service set BSS consisting of itself and multiple receiving devices Sink, and the sound source device Source and the receiving device Sink are provided with WiFi communication modules; When audio needs to be played, the audio source device Source obtains the audio data to be played and forwards it to the Sink device in the BSS network; the audio source device Source processes the obtained audio data to encapsulate the audio data of different audio channels Channel in different data packets and sends them in sequence. The sent data packets do not require the Sink device to reply with an ACK message; The receiving device Sink connected to the BSS network receives the audio data packets corresponding to one or more audio channels Channel configured by itself from the data packets sent by the audio source device according to its own configuration information, and then plays the received audio data.

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