Wireless audio playing system and system on chip

Abstract

The present application relates to a wireless audio playing system and a system on chip. The wireless audio playing system comprises an audio receiving node, at least one composite node and an audio playing node, which are sequentially connected in series, wherein the audio receiving node receives an audio data packet from an audio source, determines a synchronous playtime of the audio data packet in the wireless audio playing system, and forwards the audio data packet and the synchronous playtime to a neighbouring composite node; each composite node receives the audio data packet from a previous-stage composite node or the audio receiving node, updates the synchronous playtime and then forwards the audio data packet and an updated playtime to a next-stage composite node or the audio playing node, and makes an audio playing device, which is connected thereto, play the audio data packet at the updated synchronous playtime; and the audio playing node plays the audio data packet at the updated synchronous playtime. The wireless audio playing system of the present application can synchronously play, by means of cascading nodes, audio within an extended range without using a router.

Description

Wireless audio playback systems and system-on-chips Technical Field

[0001] The present application relates to the field of wireless communication technology, and more specifically, to a wireless audio playback system and a system on a chip. Background Art

[0002] With the development of wireless communication technology, wireless audio technology has been widely used. However, when it is desired to play audio synchronously in a larger space or in multiple corners or rooms, the wireless signal often cannot be stably connected due to distance issues, resulting in a decrease in audio playback quality.

[0003] To address this issue, the industry typically expands wireless connectivity by adding routers. However, routers have complex internal protocols, leading to significant playback delays for audio data forwarded through them. Furthermore, routers have limited communication range, high power consumption, and high cost.

[0004] It can be seen that no effective technical means have been found in the prior art to flexibly expand the coverage of wireless audio synchronous playback at a relatively low cost.

[0005] Summary of the Invention

[0006] The present application is provided to solve the above-mentioned problems existing in the prior art.

[0007] A wireless audio playback system and system-on-chip are needed that can expand the range of wireless audio playback without using a router, thereby meeting users' needs for wireless audio synchronization playback in a larger space or in multiple corners or rooms in a more flexible and lower-cost manner.

[0008] According to a first aspect of the present application, a wireless audio playback system is provided, comprising an audio receiving node, at least one composite node, and an audio playback node connected in series in sequence, wherein the audio receiving node is configured to receive an audio data packet from an audio source, determine a synchronous playback time of the audio data packet in the wireless audio playback system, and forward the received audio data packet and the corresponding synchronous playback time to an adjacent composite node using a first wireless link between the audio receiving node and an adjacent composite node; each composite node is configured to receive an audio data packet from an upper-level composite node or an audio receiving node, update the synchronous playback time, and forward the audio data packet and the updated synchronous playback time to an adjacent lower-level composite node or an adjacent audio playback node via a second wireless link; and, enable the connected audio playback device to play the audio data packet at the updated synchronous playback time; the audio playback node is configured to receive the audio data packet and the updated synchronous playback time forwarded by the previous-level composite node, and play the audio data packet at the updated synchronous playback time.

[0009] According to a second aspect of the present application, a system-on-chip (SoC) for a composite node in a wireless audio playback system is provided. The wireless audio playback system includes an audio receiving node, at least one composite node, and an audio playback node connected in series. The SoC is connected to an audio playback device for audio playback. The SoC includes a wireless communication module configured to obtain an audio data packet with a synchronized playback time from an adjacent, previous-level audio receiving node or composite node in the wireless audio playback system, wherein the synchronized playback time is the time at which the audio data packet is synchronized to be played in the wireless audio playback system. The SoC also includes a processor core configured to: obtain the audio data packet from the wireless communication module; update the synchronized playback time of the audio data packet in the wireless audio playback system; and control the audio playback device to play the audio data packet at the updated synchronized playback time. The wireless communication module is further configured to forward the audio data packet and the updated synchronized playback time to an adjacent, next-level composite node or adjacent audio playback node, so that the adjacent, next-level composite node or adjacent audio playback node plays the audio data packet at the updated synchronized playback time.

[0010] By utilizing the wireless audio playback system and system-on-chip according to the various embodiments of the present application, the wireless audio playback range can be expanded without router networking, only by cascading the audio receiving node, at least one composite node and the audio playback node, and the synchronous playback time of the audio data packet is sent together with the audio data packet to the next level node, which can ensure the synchronous playback of audio throughout the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the drawings, which are not necessarily drawn to scale, the same reference numerals may describe similar components in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar components. The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the description and claims, serve to illustrate the disclosed embodiments. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive of the embodiments of the present apparatus or method.

[0012] FIG1 shows a block diagram of a wireless audio playback system and its peripheral components according to an embodiment of the present application.

[0013] FIG2 shows a partial block diagram of a wireless audio playback system and its peripheral components according to another embodiment of the present application.

[0014] FIG3 shows a schematic diagram of the composition structure of a composite node according to an embodiment of the present application.

[0015] FIG4 shows a schematic diagram of the composition structure of a composite node according to another embodiment of the present application.

[0016] FIG5 shows a block diagram of a system on a chip and its peripheral components for a composite node in a wireless audio playback system according to an embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific embodiments, but are not intended to limit the present application.

[0018] The words "first", "second" and similar terms used in this application do not indicate any order, quantity or importance, but are only used to distinguish. Words such as "include" or "comprise" mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements. The execution order of the various steps in the method described in this application with reference to the accompanying drawings is not intended to be limiting. As long as the logical relationship between the various steps is not affected, several steps can be integrated into a single step, a single step can be decomposed into multiple steps, and the execution order of the various steps can be changed according to specific needs.

[0019] It should also be understood that the term "and / or" in this application is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " in this application generally indicates that the associated objects are in an "or" relationship.

[0020] The present application provides a wireless audio playback system, which can be used for wireless transmission and synchronous playback of audio in a larger space, or in multi-corner spaces and multi-room scenarios.

[0021] Figure 1 illustrates a block diagram of a wireless audio playback system and its peripheral components according to an embodiment of the present application. As shown in Figure 1, the wireless audio playback system 100 includes an audio receiving node 102, at least one composite node 103, and an audio playback node 104, which are sequentially connected in series. In other embodiments, there may be multiple composite nodes, such as composite node 103a (not shown). In this case, each composite node is sequentially connected in series, with the last composite node connected to the audio playback node 104.

[0022] In some embodiments, the audio receiving node 101 can be configured to: receive audio data packets from the audio source 101, determine the synchronous playback time of the audio data packets in the wireless audio playback system 100, and use the first wireless link L1 between the audio receiving node 102 and the adjacent composite node 103 to forward the received audio data packets and the corresponding synchronous playback time to the adjacent composite node 103.

[0023] Taking the composite node 103 as an example, each composite node in the wireless audio playback system 100 can be configured to: receive an audio data packet from the upper composite node or audio receiving node (for the composite node 103, the upper node is the audio receiving node 102), update the synchronous play time, and forward the audio data packet and the updated synchronous play time to the adjacent lower composite node or adjacent audio playback node via the second wireless link L2 (for the composite node 103, it has no adjacent lower composite node, so it will forward the audio data packet and the updated synchronous play time to the adjacent audio playback node 104). In addition, each composite node taking the composite node 103 as an example can also send the audio data packet to the audio playback device 1031 connected thereto via an audio interface, so that it can play the audio data packet at the updated synchronous play time. In some embodiments, each composite node can be further configured to send the audio data packet with the updated synchronous play time to the audio playback device via the I2S bus (Inter-IC Sound bus, also known as the integrated circuit built-in audio bus) so that the audio playback device plays the audio data packet at the updated synchronous play time.

[0024] In some embodiments, the audio playback node 104 may be configured to receive the audio data packet and the updated synchronous playback time forwarded by the previous-level composite node 103 , and play the audio data packet at the updated synchronous playback time.

[0025] As an example only, the first wireless link L1 between the audio receiving node 102 and the adjacent composite node 103, and the second wireless link L2 between the composite node 103 and the next-level composite node or the adjacent audio playback node 104 may include, but are not limited to, a WiFi link. As long as it has sufficient bandwidth resources and can be used for real-time transmission of audio data packets, the type of link is not specifically limited. The first wireless link L1 and the second wireless link L2 equipped with the same composite node can be wireless links of the same type or different types, and this application does not limit this.

[0026] According to the wireless audio playback system 100 of the embodiment of the present application, the wireless audio playback range can be expanded by cascading audio receiving nodes, one or more composite nodes, and audio playback nodes. Moreover, since each node carries the time at which the audio data packet is uniformly and synchronously played by each node in the system when forwarding the audio data packet to the next node, in application scenarios such as whole-house audio, as long as the distributed nodes play according to the synchronized playback time, the audio can be ensured to be synchronously delivered to every corner or room in the entire residential or commercial space.

[0027] FIG2 shows a block diagram of a wireless audio playback system and its peripheral components according to another embodiment of the present application. As shown in FIG2 , in the wireless audio playback system 200, the audio receiving node 102, the composite node 103, and the audio playback device 1031 connected to the composite node 103 all have the same or similar configuration as the corresponding components in FIG1 , and are not described in detail here. Unlike FIG1 , the audio receiving node, which is the last-level node in the wireless audio playback system 200, is specifically implemented as a composite node 105. Since it does not have a subsequent node, the audio data packet is no longer forwarded, and the audio data packet is only played at the synchronized playback time carried by the audio data packet.

[0028] The above-mentioned method of implementing the last-level node of the wireless audio playback system as a composite node can conveniently be implemented by continuing to connect composite nodes or audio playback nodes in series on the basis of the last-level composite node when the synchronous playback range of the wireless audio needs to be further expanded, thereby making the wireless audio playback system have better scalability.

[0029] In some embodiments, the number of levels of composite nodes connected in series according to the embodiments of the present application can be determined in association with the space that the wireless audio playback system wants to cover. The larger the space and the more corners or rooms there are, the more levels of composite nodes that need to be connected in series. The specific arrangement of each composite node and audio playback node can be specifically calculated and optimized based on the communication range of the first wireless link and each second wireless link. The specific method is not limited in this application.

[0030] In some embodiments, the audio receiving node may be further configured to determine the synchronous playback time of the audio data packet in the wireless audio playback system based on the number of serially connected nodes in the wireless audio playback system. As an example only, the synchronous playback time may be calculated according to the following formula (1):

[0031] Among them, Playtime1 is the synchronized playback time calculated by the audio receiving node; current_time1 is the current time of the audio receiving node based on the node's internal time reference. If the first wireless link has a time reference, the time reference of the first wireless link can be used as the node's internal time reference. For example, if the first wireless link of the audio receiving node is WiFi, then current_time1 can use the WiFi beacon TSF (a commonly used MAC timer in WiFi, used to record timestamps and timeout statistics, etc.) as its node's internal time reference.

[0032] In formula (1), n ​​is the number of nodes connected in series, delay iis the delay parameter of the i-th level node, and the value of i ranges from 1 to n, that is, the delay time of the audio data packet is the accumulation of the delay parameters of each level. i The specific value of can be determined based on a comprehensive consideration of multiple factors, including the audio playback latency requirements of the wireless audio playback system, the number of serially connected nodes in the wireless audio playback system, and the estimated processing latency of each node. For example, if both the first and second wireless links are WiFi links, and the number of serially connected nodes is three, i.e., n = 3, and the processing time of each node is estimated to be approximately 20ms, then, The value can be configured as 3*20ms=60ms. This delay value can be pre-configured by the user or specifically set according to the node composition structure and parameter configuration of the system. It can also be determined by the audio receiving node after self-calculation based on a pre-set algorithm. This application does not impose any restrictions on this.

[0033] After the audio receiving node calculates the synchronous playback time Playtime1, it needs to package the time together with the audio data packet and send it to the next-level composite node. Next, when the composite node receives the audio data packet with the synchronous playback time, it needs to determine whether it needs to recalculate and update the synchronous playback time. When its own node happens to be the last-level audio playback node, since there is no need to forward the audio data packet, there is no need to update the synchronous playback time; when it is not the last-level audio playback node, it is necessary to update the synchronous playback time and forward the updated synchronous playback time and the audio data packet to the next-level node. Specifically, each composite node can combine the number of serial connection levels of nodes in the wireless audio playback system and the number of layers of its own node, based on the time base of the first wireless link between the adjacent previous-level audio receiving node, or the time base of the second wireless link between the adjacent previous-level composite node, and the first delay parameter to update the synchronous playback time. Specifically, the updated synchronous playback time can be determined according to the following formula (2):

[0034] Wherein, Playtimek is the updated synchronized play time calculated by the composite node of the kth level; current_timek is the current time of the composite node determined based on the time reference of the first wireless link between the composite node and the adjacent previous level audio receiving node (or the time reference of the second wireless link between the composite node and the adjacent previous level); Δ k is the first delay parameter of the composite node, which represents the processing time on the composite node. For different composite nodes, the first delay parameter can be the same or different.

[0035] In formula (2), n is the number of nodes connected in series, delay i is the delay parameter for the i-th level node, k is the level of the current composite node, and i ranges from k+1 to n. This means that the delay time for the audio packet is the sum of the delay parameters for each level, from the current composite node to the last. Using the first delay parameter as a more accurate processing time estimate for the current composite node allows for more accurate updates of the synchronized playback time of the audio packet.

[0036] In some embodiments, after receiving the audio data packet, the composite node / audio playback node places it into a queue to be played. When the corresponding synchronous playback arrives, the audio playback devices on each node will play simultaneously, thereby achieving synchronous playback of audio in the wireless audio playback system.

[0037] Unlike existing wireless audio playback systems that are implemented via router networking, the wireless audio playback system shown in Figures 1 and 2 does not require a router at all. That is, the nodes in the wireless audio playback system do not need to be connected to a common router device, and the audio receiving node, each composite node, and the audio playback node do not need to have network routing capabilities. In particular, for the audio receiving node, it only needs to have a function similar to SoftAP; for the composite node, it only needs to have the function of Station (workstation) + SoftAP; and for the audio playback node, it only needs to have the function of Station. Specifically, SoftAP refers to an AP (Access Point, also known as a base station) implemented in software, which can complete the wireless-to-wired bridging function of the base station. Station refers to a device equipped with a wireless link interface, which can be specifically implemented as a laptop or handheld computer, or a speaker device with a wireless link interface, etc. The specific implementation method is not limited in this application, as long as it can receive audio data packets via a wireless link.

[0038] Figure 3 illustrates a schematic diagram of the structure of a composite node according to an embodiment of the present application. Figure 3 illustrates a specific implementation of a composite node 103 corresponding to the embodiment in Figure 1 , wherein the audio receiving node 102 in Figure 1 is implemented as the SoftAP0 in Figure 3 , which is configured to receive audio data packets from an audio source 101 via a wired connection 1 such as a USB interface and transmit the audio data packets to the composite node 103 via a first wireless link L1. The internal implementation of the composite node 103 is a Station+SoftAP structure. Specifically, the station Station1 receives the audio data packet via the first wireless link L1 and transmits the audio data to the access point SoftAP1 via, for example, an I2S bus (I2S IN is a data input port). Then, the access point SoftAP1 transmits the audio data to the audio playback device 1031 connected thereto via, for example, an I2S bus (I2S OUT is a data output port), so that the audio playback device 1031 plays the audio at the synchronized playback time of the audio data. On the other hand, the audio data packet is sent to the audio playback node implemented as the station Station2 (corresponding to the audio playback node 104 in Figure 1) via the second wireless link L2, so that the station Station2 can transmit the audio data to the audio playback device 1041 connected thereto via, for example, an I2S bus, thereby playing the audio data at a synchronized playback time uniform across the entire system. It is worth noting that, in the composite node 103 , the audio playback device 1031 may also be connected to the station Station 1 via the I2S bus, and the station Station 1 may send audio data to the audio playback device 1031 for synchronous playback.

[0039] FIG4 illustrates a schematic diagram of the structure of a composite node according to another embodiment of the present application. FIG4 illustrates the specific implementation of composite nodes 103 and 104 corresponding to the embodiment of FIG2 , wherein the audio receiving node 102 in FIG2 is implemented as SoftAP0 in FIG4 . Similar to the embodiment corresponding to FIG3 , the internal implementation of composite node 103 is a Station+SoftAP structure. The functions and configurations of station Station1 and access point SoftAP1 are also similar to the corresponding components in FIG3 , but its audio playback device 1031 is connected to station Station1 instead of access point SoftAP1. After composite node 105 receives audio data packets via the second wireless link L2, it further transmits them to access point SoftAP2 via the I2S bus. Access point SoftAP2 then sends the audio data to the connected audio playback device 1051 via the I2S bus for synchronous playback. In this case, when the wireless audio playback system needs to further expand its coverage, other composite nodes (not shown) or audio playback nodes (not shown) can be further connected in series at the subsequent stage of the composite node 105, and the access point SoftAP2 in the composite node 105 uses its wireless link (not shown) to send the audio data packet together with the corresponding synchronized playback time to the subsequent node.

[0040] In some embodiments, a composite node can be implemented as a dual-chip, with the Station and SoftAP components within the composite node being separate chips connected via internal node circuitry or interfaces. In other embodiments, the functions and circuitry of the Station and SoftAP components can be integrated and optimized, enabling coexistence of the Station and SoftAP components on a single chip. This reduces the complexity of the node's circuitry and device, making it more convenient to use.

[0041] In the prior art, wireless audio playback systems usually rely on router networking, which has complex router protocols and long processing delays. In addition, there are defects such as high power consumption and insufficient communication distance. In particular, when it is necessary to expand the coverage of the system, the multi-router networking protocol will become more complicated, the protocol overhead of nodes accessing the multi-router network will be greater, the delay of audio data packets forwarding between the multi-router networks will also increase, and the user experience will decline. However, the wireless audio playback system according to the embodiment of the present application can achieve flexible expansion of the audio playback range simply by cascading general composite nodes with the same configuration, without the need for additional network access processes, with low protocol overhead and more controllable audio data packet transmission delay.

[0042] According to an embodiment of the present application, a system on chip (SoC) for a composite node in a wireless audio playback system is also provided. FIG5 shows a block diagram of the system on chip and its peripheral components for a composite node in a wireless audio playback system according to an embodiment of the present application.

[0043] As shown in FIG5 , the wireless audio playback system 100 has been described in conjunction with FIG1 , and may include an audio receiving node 102 , at least one composite node 103 , and an audio playback node 104 connected in series. The system on chip 500 may be applied to at least the composite node 103 .

[0044] In some embodiments, the system on chip 500 may be connected to an audio playback device 1031 for audio playback, and the two may communicate via a general or dedicated bus / interface connection.

[0045] The system on chip 500 may further include a wireless communication module 501, which may include a first wireless link L1 and a second wireless link L2. L1 and L2 may adopt any one or more of WiFi, Bluetooth wireless communication modules, Zigbee wireless communication modules, and NFC wireless communication modules, which are not described in detail here. In some embodiments, an audio data packet with a synchronized playback time is obtained from an adjacent previous-level audio receiving node 102 or composite node (in this embodiment, the previous level is an audio receiving node) in the wireless audio playback system 100 via the first wireless link L1, wherein the synchronized playback time is the time at which the audio data packet is synchronizedly played in the wireless audio playback system 100.

[0046] The processor core 502 can be configured to obtain audio data packets from the wireless communication module 501, update the synchronous playback time of the audio data packets in the wireless audio playback system 100, and control the audio playback device 1031 to play the audio data packets at the updated synchronous playback time. The processor core 502 can include any Cortex A series processor, such as but not limited to Cortex A5, Cortex A7, Cortex A8, Cortex A9, or any Cortex M series processor, including but not limited to Cortex M4, Cortex M7, Cortex M23, Cortex M33, Cortex M55, etc., which are not further described here.

[0047] In addition, the wireless communication module 501 can be further configured to forward the audio data packet and the updated synchronous playback time to the adjacent next-level composite node (not shown) or the adjacent audio playback node 104 via the second wireless link L2, so that the adjacent next-level composite node or the adjacent audio playback node 104 plays the audio data packet at the updated synchronous playback time.

[0048] In other embodiments, the system-on-chip may also function as an audio receiving node, that is, directly receiving audio data from an audio source. In this case, the system-on-chip may further include an audio interface configured to obtain audio data packets from the audio source. Furthermore, the processor core may be configured to obtain audio data packets from the audio source via the audio interface and determine a synchronized playback time for the audio data packets in the wireless audio playback system.

[0049] In other embodiments, the processor core of the system-on-chip can be further configured to update the synchronized playback time based on the time reference of the first wireless link between the audio receiving node of the adjacent previous level, or the time reference of the second wireless link between the composite node of the adjacent previous level, and the first delay parameter, in combination with the number of serially connected nodes in the wireless audio playback system and the layer number of the node itself. The specific method for determining the synchronized playback time has been described in detail in the aforementioned embodiments and will not be repeated here.

[0050] Furthermore, although exemplary embodiments have been described herein, the scope includes any and all embodiments based on the present application having equivalent elements, modifications, omissions, combinations (eg, schemes that intersect various embodiments), adaptations, or changes.

[0051] The elements of the claims are to be interpreted broadly based on the language employed in the claims and not limited to the examples described in this specification or during the prosecution of the application, which examples are to be construed as non-exclusive. Accordingly, it is intended that the specification and examples be considered as examples only, with the true scope and spirit being indicated by the claims and their full scope of equivalents.

[0052] The order of the steps in this application is merely exemplary and non-restrictive. The order of the steps may be adjusted without affecting the implementation of this application (without disrupting the required logical relationships between the steps), and the resulting embodiments will still fall within the scope of this application.

[0053] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more of their solutions) can be used in combination with each other. For example, a person of ordinary skill in the art may use other embodiments when reading the above description. In addition, in the above-mentioned specific embodiments, various features can be grouped together to simplify the application. This should not be interpreted as an intention that a disclosed feature that is not required to be protected is necessary for any claim. On the contrary, the subject matter of the present invention may be less than all the features of a specific disclosed embodiment. Thus, the claims are incorporated into the specific embodiments as examples or embodiments, wherein each claim is independently a separate embodiment, and it is considered that these embodiments can be combined with each other in various combinations or arrangements. The scope of the present invention should be determined with reference to the claims and the full scope of equivalents to which these claims are entitled.

Claims

1. A wireless audio playback system, characterized in that: The wireless audio playback system comprises an audio receiving node, at least one composite node and an audio playback node which are serially connected in sequence, wherein: The audio receiving node is configured to: receive an audio data packet from an audio source, determine a synchronous playback time of the audio data packet in the wireless audio playback system, and forward the received audio data packet and the corresponding synchronous playback time to the adjacent composite node using a first wireless link between the audio receiving node and the adjacent composite node; Each composite node is configured to: receive an audio data packet from an upper-level composite node or an audio receiving node, update the synchronous play time, and forward the audio data packet and the updated synchronous play time to an adjacent lower-level composite node or an adjacent audio play node via a second wireless link; and enable the connected audio play device to play the audio data packet at the updated synchronous play time; The audio playing node is configured to receive the audio data packet and the updated synchronous playing time forwarded by the previous level composite node, and play the audio data packet at the updated synchronous playing time.

2. The wireless audio playback system according to claim 1, characterized in that: The audio receiving node is specifically implemented as a composite node, which is further configured to: play the audio data packet at the synchronous play time.

3. The wireless audio playback system according to claim 1 or 2, characterized in that: The audio receiving node is further configured to: determine the synchronous playback time of the audio data packet in the wireless audio playback system in combination with the number of serially connected nodes in the wireless audio playback system; Each composite node is further configured to update the synchronous playback time based on the time reference of the first wireless link between the audio receiving node of the adjacent previous level, or the time reference of the second wireless link between the composite node of the adjacent previous level, and the first delay parameter, in combination with the number of levels of serial connection of nodes in the wireless audio playback system and the number of layers at which the node itself is located.

4. The wireless audio playback system according to claim 1 or 2, characterized in that: The audio receiving node is further configured to receive audio data packets from an audio source via a wired connection.

5. The wireless audio playback system according to claim 1 or 2, characterized in that: The audio receiving node and each composite node do not have network routing capability.

6. The wireless audio playback system according to claim 1 or 2, characterized in that: The first wireless link and each second wireless link are WiFi links.

7. The wireless audio playback system according to claim 1 or 2, characterized in that The composite node is connected to the audio playback device via an I2S bus, and each composite node is further configured as follows: The audio data packet with the updated synchronous play time is sent to the audio playing device via the I2S bus so that the audio playing device plays the audio data packet at the updated synchronous play time.

8. A system on chip for a composite node in a wireless audio playback system, characterized in that: The wireless audio playback system comprises an audio receiving node, at least one composite node and an audio playback node connected in series in sequence, the system on chip is connected to an audio playback device for audio playback, and the system on chip comprises: A wireless communication module configured to obtain, via a first wireless link, an audio data packet with a synchronous playback time from an adjacent previous-level audio receiving node or composite node in the wireless audio playback system, wherein the synchronous playback time is a time for synchronous playback of the audio data packet in the wireless audio playback system; A processor core configured to: obtain an audio data packet from the wireless communication module; update a synchronous playback time of the audio data packet in the wireless audio playback system; and control the audio playback device to play the audio data packet at the updated synchronous playback time; The wireless communication module is further configured to forward the audio data packet and the updated synchronous playback time to an adjacent next-level composite node or an adjacent audio playback node via a second wireless link, so that the adjacent next-level composite node or the adjacent audio playback node plays the audio data packet at the updated synchronous playback time.

9. The system on chip according to claim 8, characterized in that: The system on chip also includes an audio interface, The audio interface is configured to obtain an audio data packet from an audio source; The processor core is further configured to: obtain an audio data packet from an audio source via the audio interface; and determine a synchronous playback time of the audio data packet in the wireless audio playback system.

10. The system on chip according to claim 8, characterized in that: The processor core is further configured to update the synchronous playback time based on the time reference of the first wireless link between the audio receiving node of the adjacent previous level, or the time reference of the second wireless link between the composite node of the adjacent previous level, and the first delay parameter, in combination with the number of serial connection levels of the nodes in the wireless audio playback system and the layer number of the node itself.

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