Patent Publication Number: US-2022225088-A1

Title: Bluetooth communication system capable of increasing generation efficiency of cypher keys required for data transmission between bluetooth host device and bluetooth device set, and related bluetooth device set

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to U.S. Provisional Application Ser. No. 63/135,720, filed on Jan. 10, 2021; the entirety of which is incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     The disclosure generally relates to Bluetooth technologies and, more particularly, to a Bluetooth communication system and a related Bluetooth device set capable of increasing generation efficiency of cypher keys required for data transmission between a Bluetooth host device and the Bluetooth device set. 
     There are two categories of Bluetooth technologies: Classic Bluetooth/Legacy Bluetooth technology and BLE (Bluetooth Low Energy) technology. The BLE technology is incompatible (or not completely compatible) with the Classic Bluetooth/Legacy Bluetooth technology, but the two technologies can coexist in the same Bluetooth device or the same Bluetooth chip. In other words, a single Bluetooth device or a single Bluetooth chip may be designed to support both the BLE technology and the Classic Bluetooth/Legacy Bluetooth technology, or may be designed to support only one category of the Bluetooth communication standards. The newly launched Bluetooth LE Audio (BLE Audio) technology (hereinafter referred to as the BLE Audio technology) based on Bluetooth Core Specification Version 5.2 is a significant update to the technical specifications of audio transmission over the past twenty years of development of Bluetooth technologies. The main advantage of the BLE Audio technology is that the BLE Audio technology can transmit audio with higher quality while significantly reducing power consumption. It is foreseeable that the market demand for Bluetooth device set (e.g., a pair of Bluetooth earphones, a group of multi-channel Bluetooth speakers, or the like) that can support the BLE Audio technology will become higher and higher. 
     As is well known in related art, when a Bluetooth device set which adopts the Classic Bluetooth/Legacy Bluetooth technology connects to a Bluetooth host device (e.g., a cell phone, a computer, or the like), the Bluetooth host device treats multiple member devices in the Bluetooth device set as a single Bluetooth device. Therefore, the Bluetooth host device only needs to establish a connection with one of the multiple member devices in the Bluetooth device set. 
     However, according to specification of the BLE Audio technology, when a Bluetooth device set which supports the BLE Audio technology wants to connect to a Bluetooth host device, the Bluetooth host device has to conduct Bluetooth pairing procedure with all member devices in the Bluetooth device set one by one, so that the Bluetooth host device can successfully transmit audio data or other data to all member devices in the Bluetooth device set. According to the existing technology, the Bluetooth pairing process between the Bluetooth host device and respective member devices in the Bluetooth device set will be quite lengthy. One of the main reasons is that the Bluetooth host device has to spend a lot of time negotiating with individual member devices one by one regarding the relevant parameters of the cypher keys to be generated by both parties. The greater the number of member devices in the Bluetooth device set, the longer the time it takes for the Bluetooth host device and the Bluetooth device set in generating the required cypher keys. 
     Accordingly, if the generation efficiency of the cypher keys required for subsequent data transmission between the Bluetooth host device and the Bluetooth device set cannot be improved, it will seriously hinder the development prospects of the BLE Audio technology in the related applications of the Bluetooth device sets. 
     SUMMARY 
     An example embodiment of a Bluetooth communication system is disclosed, comprising: a Bluetooth host device, comprising: a host-side communication circuit; a host-side cypher key generation circuit; a processing circuit, coupled with the host-side communication circuit and the host-side cypher key generation circuit, arranged to operably control operations of the host-side communication circuit and the host-side cypher key generation circuit; and a Bluetooth device set, comprising at least a first member device and a second member device; wherein the first member device comprises: a first communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and to operably generate one or more target Bluetooth advertising packets containing an auto-pair request and a device information of the first member device, and to operably utilize the first communication circuit to transmit the one or more target Bluetooth advertising packets to the Bluetooth host device; wherein the second member device comprises: a second communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the host-side communication circuit is further arranged to operably receive the one or more target Bluetooth advertising packets; wherein the processing circuit is further arranged to operably identify the first member device as a first privileged device according to the auto-pair request in the one or more target Bluetooth advertising packets, and after identifying the first member device as the first privileged device, the processing circuit is arranged to operably transmits a first privileged pairing notice to the first member device through the host-side communication circuit, and to operably generate a first cypher key; wherein the first control circuit is further arranged to operably generate a second cypher key corresponding to the first cypher key after the first privileged pairing notice is received by the first communication circuit. 
     An example embodiment of a Bluetooth device set of a Bluetooth communication system is disclosed, comprising: a first member device, comprising: a first communication circuit, arranged to operably conduct wireless communications with a Bluetooth host device in the Bluetooth communication system; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, to operably generate one or more target Bluetooth advertising packets containing an auto-pair request and a device information of the first member device, and to operably utilize the first communication circuit to transmit the one or more target Bluetooth advertising packets to the Bluetooth host device; a second member device, comprising: a second communication circuit, arranged to operably conduct wireless communications with the Bluetooth host device; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the Bluetooth host device identifies the first member device as a first privileged device according to the auto-pair request in the one or more target Bluetooth advertising packets, and after identifying the first member device as the first privileged device, the Bluetooth host device transmits a first privileged pairing notice to the first member device, and generates a first cypher key; wherein the first control circuit is further arranged to operably generate a second cypher key corresponding to the first cypher key after the first privileged pairing notice is received by the first communication circuit. 
     Another example embodiment of a Bluetooth communication system is disclosed, comprising: a Bluetooth host device, comprising: a host-side communication circuit; a host-side cypher key generation circuit; and a processing circuit, coupled with the host-side communication circuit and the host-side cypher key generation circuit, and arranged to operably control operations of the host-side communication circuit and the host-side cypher key generation circuit; and a Bluetooth device set, comprising at least a first member device and a second member device; wherein the first member device comprises: a first communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably generate one or more target Bluetooth advertising packets containing a device information of the first member device and the first resolvable set identifier, and arranged to operably utilize the first communication circuit to transmit the one or more target Bluetooth advertising packets to the Bluetooth host device; wherein the second member device comprises: a second communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; and a second control circuit, coupled with the second communication circuit, arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the host-side communication circuit is further arranged to operably receive the one or more target Bluetooth advertising packets; wherein the processing circuit is further arranged to operably control a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the processing circuit is further arranged to operably identify the first member device as a first privileged device according to a position of the first resolvable set identifier in the one or more target Bluetooth advertising packets, and after identifying the first member device as the first privileged device, the processing circuit is further arranged to operably transmit a first privileged pairing notice to the first member device through the host-side communication circuit, and to operably generate a first cypher key; wherein the first control circuit is further arranged to operably generate a second cypher key corresponding to the first cypher key after the first privileged pairing notice is received by the first communication circuit. 
     Another example embodiment of a Bluetooth device set of a Bluetooth communication system is disclosed, comprising: a first member device, comprising: a first communication circuit, arranged to operably conduct wireless communications with a Bluetooth host device in the Bluetooth communication system; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably generate one or more target Bluetooth advertising packets containing a device information of the first member device and the first resolvable set identifier, and arranged to operably utilize the first communication circuit to transmit the one or more target Bluetooth advertising packets to the Bluetooth host device; a second member device, comprising: a second communication circuit, arranged to operably conduct wireless communications with the Bluetooth host device; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the Bluetooth host device controls a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the Bluetooth host device identifies the first member device as a first privileged device according to a position of the first resolvable set identifier in the one or more target Bluetooth advertising packets, and after identifying the first member device as the first privileged device, the Bluetooth host device transmits a first privileged pairing notice to the first member device and generates a first cypher key; wherein the first control circuit is further arranged to operably generate a second cypher key corresponding to the first cypher key after the first privileged pairing notice is received by the first communication circuit. 
     Another example embodiment of a Bluetooth communication system is disclosed, comprising: a Bluetooth host device, comprising: a host-side communication circuit; a host-side cypher key generation circuit; and a processing circuit, coupled with the host-side communication circuit and the host-side cypher key generation circuit, and arranged to operably control operations of the host-side communication circuit and the host-side cypher key generation circuit; and a Bluetooth device set, comprising at least a first member device and a second member device; wherein the first member device comprises: a first communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably utilize the first communication circuit to transmit a device information of the first member device to the Bluetooth host device; wherein the second member device comprises: a second communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; and a second control circuit, coupled with the second communication circuit, arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the processing circuit is further arranged to operably control a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the processing circuit is further arranged to operably utilize the host-side communication circuit to establish a connection with the first member device and to conduct a pairing procedure to generate a first cypher key after receiving a selection command issued by an user; wherein the first control circuit is further arranged to operably utilize the first communication circuit to establish a connection with the Bluetooth host device and to conduct a pairing procedure to generate a second cypher key corresponding to the first cypher key. 
     Another example embodiment of a Bluetooth device set of a Bluetooth communication system is disclosed, comprising: a first member device, comprising: a first communication circuit, arranged to operably conduct wireless communications with a Bluetooth host device in the Bluetooth communication system; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably utilize the first communication circuit to transmit a device information of the first member device to the Bluetooth host device; a second member device, comprising: a second communication circuit, arranged to operably conduct wireless communications with the Bluetooth host device; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the Bluetooth host device controls a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the Bluetooth host device establishes a connection with the first member device and conducts a pairing procedure to generate a first cypher key after receiving a selection command issued by an user; wherein the first control circuit is further arranged to operably utilize the first communication circuit to establish a connection with the Bluetooth host device and to conduct a pairing procedure to generate a second cypher key corresponding to the first cypher key. 
     Another example embodiment of a Bluetooth communication system is disclosed, comprising: a Bluetooth host device, comprising: a host-side communication circuit; a host-side cypher key generation circuit; and a processing circuit, coupled with the host-side communication circuit and the host-side cypher key generation circuit, and arranged to operably control operations of the host-side communication circuit and the host-side cypher key generation circuit; and a Bluetooth device set, comprising at least a first member device and a second member device; wherein the first member device comprises: a first communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably utilize the first communication circuit to transmit a device information of the first member device to the Bluetooth host device; wherein the second member device comprises: a second communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the processing circuit is further arranged to operably control a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the processing circuit is further arranged to operably utilize the host-side communication circuit to establish a connection with the first member device and to conduct a pairing procedure to generate a first cypher key after receiving a selection command issued by an user; wherein the first control circuit is further arranged to operably utilize the first communication circuit to establish a connection with the Bluetooth host device and to conduct a pairing procedure to generate a second cypher key corresponding to the first cypher key. 
     Another example embodiment of a Bluetooth device set of a Bluetooth communication system is disclosed, comprising: a first member device, comprising: a first communication circuit, arranged to operably conduct wireless communications with a Bluetooth host device in the Bluetooth communication system; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably utilize the first communication circuit to transmit a device information of the first member device to the Bluetooth host device; a second member device, comprising: a second communication circuit, arranged to operably conduct wireless communications with the Bluetooth host device; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the Bluetooth host device controls a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the Bluetooth host device establishes a connection with the first member device and conducts a pairing procedure to generate a first cypher key after receiving a selection command issued by an user; wherein the first control circuit is further arranged to operably utilize the first communication circuit to establish a connection with the Bluetooth host device and to conduct a pairing procedure to generate a second cypher key corresponding to the first cypher key. 
     Another example embodiment of a Bluetooth communication system is disclosed, comprising: a Bluetooth host device, comprising: a host-side communication circuit; a host-side cypher key generation circuit; and a processing circuit, coupled with the host-side communication circuit and the host-side cypher key generation circuit, and arranged to operably control operations of the host-side communication circuit and the host-side cypher key generation circuit; and a Bluetooth device set, comprising at least a first member device and a second member device; wherein the first member device comprises: a first communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably utilize the first communication circuit to transmit a device information of the first member device to the Bluetooth host device; wherein the second member device comprises: a second communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the processing circuit is further arranged to operably control a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the processing circuit is further arranged to operably utilize the host-side communication circuit to establish a connection with the first member device after receiving a selection command issued by an user, and to operably generate a first cypher key according to instructions of the first member device and the device information of the first member device; wherein the first control circuit is further arranged to operably utilize the first communication circuit to establish a connection with the Bluetooth host device, and to operably generate a second cypher key corresponding to the first cypher key according to a device information of the Bluetooth host device. 
     Another example embodiment of a Bluetooth device set of a Bluetooth communication system is disclosed, comprising: a first member device, comprising: a first communication circuit, arranged to operably conduct wireless communications with a Bluetooth host device in the Bluetooth communication system; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably utilize the first communication circuit to transmit a device information of the first member device to the Bluetooth host device; a second member device, comprising: a second communication circuit, arranged to operably conduct wireless communications with the Bluetooth host device; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the Bluetooth host device controls a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the Bluetooth host device establishes a connection with the first member device after receiving a selection command issued by an user, and generates a first cypher key according to instructions of the first member device and the device information of the first member device; wherein the first control circuit is further arranged to operably utilize the first communication circuit to establish a connection with the Bluetooth host device, and to operably generate a second cypher key corresponding to the first cypher key according to a device information of the Bluetooth host device. 
     Another example embodiment of a Bluetooth communication system is disclosed, comprising: a Bluetooth host device, comprising: a host-side communication circuit; a host-side cypher key generation circuit; and a processing circuit, coupled with the host-side communication circuit and the host-side cypher key generation circuit, and arranged to operably control operations of the host-side communication circuit and the host-side cypher key generation circuit; and a Bluetooth device set, comprising at least a first member device and a second member device; wherein the first member device comprises: a first communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably utilize the first communication circuit to transmit a device information of the first member device to the Bluetooth host device; wherein the second member device comprises: a second communication circuit, arranged to operably conduct wireless communications with the host-side communication circuit; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the processing circuit is further arranged to operably control a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the processing circuit is further arranged to operably utilize the host-side communication circuit to transmit a first parameter or a first field indication to the first member device after receiving a selection command issued by an user, and to operably execute a predetermined cypher key algorithm according to the first parameter to generate a first cypher key; wherein the first control circuit is further arranged to operably utilize the first communication circuit to receive the first parameter or the first field indication, and to operably execute the predetermined cypher key algorithm according to the first parameter to generate a second cypher key corresponding to the first cypher key. 
     Another example embodiment of a Bluetooth device set of a Bluetooth communication system is disclosed, comprising: a first member device, comprising: a first communication circuit, arranged to operably conduct wireless communications with a Bluetooth host device in the Bluetooth communication system; a first cypher key generation circuit; and a first control circuit, coupled with the first communication circuit and the first cypher key generation circuit, and arranged to operably generate a first resolvable set identifier corresponding to the first member device according to a device set identification information corresponding to the Bluetooth device set, and arranged to operably utilize the first communication circuit to transmit a device information of the first member device to the Bluetooth host device; a second member device, comprising: a second communication circuit, arranged to operably conduct wireless communications with the Bluetooth host device; and a second control circuit, coupled with the second communication circuit, and arranged to operably control operations of the second communication circuit, and arranged to operably generate a second resolvable set identifier corresponding to the second member device according to the device set identification information; wherein the Bluetooth host device controls a display device to display a candidate device list, and to display a single device item for representing the Bluetooth device set in the candidate device list, but does not simultaneously display two device items for respectively representing the first member device and the second member device in the candidate device list; wherein the Bluetooth host device transmits a first parameter or a first field indication to the first member device after receiving a selection command issued by an user, and executes a predetermined cypher key algorithm according to the first parameter to generate a first cypher key; wherein the first control circuit is further arranged to operably utilize the first communication circuit to receive the first parameter or the first field indication, and to operably execute the predetermined cypher key algorithm according to the first parameter to generate a second cypher key corresponding to the first cypher key. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a simplified functional block diagram of a Bluetooth communication system according to one embodiment of the present disclosure. 
         FIG. 2  and  FIG. 3  collectively show a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a first embodiment of the present disclosure. 
         FIG. 4  and  FIG. 5  collectively show a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a second embodiment of the present disclosure. 
         FIG. 6  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a third embodiment of the present disclosure. 
         FIG. 7  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a fourth embodiment of the present disclosure. 
         FIG. 8  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a fifth embodiment of the present disclosure. 
         FIG. 9  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a sixth embodiment of the present disclosure. 
         FIG. 10  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a seventh embodiment of the present disclosure. 
         FIG. 11  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to an eighth embodiment of the present disclosure. 
         FIG. 12  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a ninth embodiment of the present disclosure. 
         FIG. 13  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a tenth embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference is made in detail to embodiments of the invention, which are illustrated in the accompanying drawings. The same reference numbers may be used throughout the drawings to refer to the same or like parts, components, or operations. 
       FIG. 1  shows a simplified functional block diagram of a Bluetooth communication system  100  according to one embodiment of the present disclosure. The Bluetooth communication system  100  comprises a Bluetooth host device  110  and a Bluetooth device set  102 , wherein the Bluetooth device set  102  comprises a plurality of member devices. 
     In practical applications, the plurality of member devices in the Bluetooth device set  102  may utilize various approaches complying with the Bluetooth communication standards to create a Bluetooth piconet, and may conduct various instruction transmission or data transmission through the Bluetooth piconet. Alternatively, the plurality of member devices in the Bluetooth device set  102  may collectively form a coordinate set complying with Bluetooth communication standards. 
     In this embodiment, the Bluetooth host device  110  and all member devices in the Bluetooth device set  102  support the Bluetooth LE Audio (BLE Audio) technology (hereinafter referred to as BLE Audio technology) specified by the Bluetooth Core Specification Version 5.2 or newer versions. Accordingly, an user may connect the Bluetooth host device  110  with the Bluetooth device set  102  to utilize the Bluetooth device set  102  to conduct various audio playback operations. 
     For example, two member devices in the Bluetooth device set  102  may cooperate with appropriate audio playback circuits to collectively form a pair of Bluetooth earphones or a 2.0 channel speaker set. For another example, three member devices in the Bluetooth device set  102  may cooperate with appropriate audio playback circuits to collectively form a 2.1 channel speaker set. For another example, sis member devices in the Bluetooth device set  102  may cooperate with appropriate audio playback circuits to collectively form a 5.1 channel speaker set. For another example, eight member devices in the Bluetooth device set  102  may cooperate with appropriate audio playback circuits to collectively form a 7.1 channel speaker set. 
     In order to reduce the complexity of the drawing, only three exemplary member devices are shown in  FIG. 1 , which are a first member device  120 , a second member device  130 , and a third member device  140 . In the embodiment of  FIG. 1 , the first member device  120  is coupled with a first audio playback circuit  162  and a first voice receiving circuit  164 , the second member device  130  is coupled with a second audio playback circuit  172  and a second voice receiving circuit  174 , while the third member device  140  is coupled with a third audio playback circuit  182  and a third voice receiving circuit  184 . 
     The user may connect the Bluetooth host device  110  with the first member device  120 , the second member device  130 , and the third member device  140  in the Bluetooth device set  102 , so as to utilize above member devices to control related audio playback circuits to playback audio data transmitted from the Bluetooth host device  110  by adopting the BLE Audio technology. 
     In the embodiment of  FIG. 1 , the Bluetooth host device  110  comprises a host-side communication circuit  111 , an input circuit  113 , a host-side cypher key generation circuit  115 , and a processing circuit  117 . The first member device  120  comprises a first communication circuit  121 , a first cypher key generation circuit  123 , a first control circuit  125 , and a first audio processing circuit  127 . The second member device  130  comprises a second communication circuit  131 , a second cypher key generation circuit  133 , a second control circuit  135 , and a second audio processing circuit  137 . 
     In the Bluetooth host device  110 , the host-side communication circuit  111  is arranged to operably receive and transmit various Bluetooth packets. The input circuit  113  is arranged to operably various commands issued by the user. The host-side cypher key generation circuit  115  is arranged to operably execute various selected or predetermined cypher key algorithms to generate cypher keys required by the Bluetooth host device  110  for conducting subsequent Bluetooth data transmissions with respective member devices in the Bluetooth device set  102 . The processing circuit  117  is coupled with the host-side communication circuit  111 , the input circuit  113 , and the host-side cypher key generation circuit  115 . The processing circuit  117  is arranged to operably generate various Bluetooth packets to be transmitted by the host-side communication circuit  111 , arranged to operably parse various Bluetooth packets received by the host-side communication circuit  111  to obtain related data or instructions, and further arranged to operably control operations of the host-side cypher key generation circuit  115 . The processing circuit  117  is further arranged to operably control operations of the Bluetooth host device  110  according to various operating commands issued by the user through the input circuit  113 . 
     The term “Bluetooth packet” used throughout the description and the claims also encompass various protocol data units (PDUs) specified by various Bluetooth communication standards. 
     In some embodiments, the processing circuit  117  is further coupled with a display device  150 , and arranged to operably control operations of the display device  150 , so as to display related information or images to the user. 
     In the first member device  120 , the first communication circuit  121  is arranged to operably receive and transmit various Bluetooth packets. The first cypher key generation circuit  123  is arranged to operably execute various selected or predetermined cypher key algorithms to generate cypher keys required by the first member device  120  for conducting subsequent Bluetooth data transmissions with the Bluetooth host device  110 . The first control circuit  125  is coupled with the first communication circuit  121  and the first cypher key generation circuit  123 . The first control circuit  125  is arranged to operably generate various Bluetooth packets to be transmitted by the first communication circuit  121 , and arranged to operably parse various Bluetooth packets received by the first communication circuit  121  to acquire related data or instructions, and further arranged to operably control the cypher key generating operations of the first cypher key generation circuit  123 . In addition, the first control circuit  125  is further arranged to operably adjust the clock signals employed by the first member device  120 , so as to synchronize a piconet clock utilized among the first member device  120  and other Bluetooth devices. 
     The first audio processing circuit  127  is coupled with the first control circuit  125 , the first audio playback circuit  162 , and the first voice receiving circuit  164 . The first audio processing circuit  127  is arranged to operably process the audio data transmitted from the Bluetooth host device  110  (e.g., to encode or decode the audio data, and/or to conduct format conversion on the audio data) according to the instructions of the first control circuit  125 , and arranged to operably control the first audio playback circuit  162  to playback contents of the audio data. The first audio processing circuit  127  is further arranged to operably encode the sounds received by the first voice receiving circuit  164  to generate related sound data. 
     In the second member device  130 , the second communication circuit  131  is arranged to operably receive and transmit various Bluetooth packets. The second cypher key generation circuit  133  is arranged to operably execute various selected or predetermined cypher key algorithms to generate cypher keys required by the second member device  130  for conducting subsequent Bluetooth data transmissions with the Bluetooth host device  110 . The second control circuit  135  is coupled with the second communication circuit  131  and the second cypher key generation circuit  133 . The second control circuit  135  is arranged to operably generate various Bluetooth packets to be transmitted by the second communication circuit  131 , and arranged to operably parse various Bluetooth packets received by the second communication circuit  131  to acquire related data or instructions, and further arranged to operably control the cypher key generating operations of the second cypher key generation circuit  133 . In addition, the second control circuit  135  is further arranged to operably adjust the clock signals employed by the second member device  130 , so as to synchronize a piconet clock utilized among the second member device  130  and other Bluetooth devices. 
     The second audio processing circuit  137  is coupled with the second control circuit  135 , the second audio playback circuit  172 , and the second voice receiving circuit  174 . The second audio processing circuit  137  is arranged to operably process the audio data transmitted from the Bluetooth host device  110  (e.g., to encode or decode the audio data, and/or to conduct format conversion on the audio data) according to the instructions of the second control circuit  135 , and arranged to operably control the second audio playback circuit  172  to playback contents of the audio data. The second audio processing circuit  137  is further arranged to operably encode the sounds received by the second voice receiving circuit  174  to generate related sound data. 
     In some embodiments, the first control circuit  125  is further arranged to operably control the first member device  120  to act as a Bluetooth Central in a Bluetooth piconet, and to operably adjust the clock signals employed by the first member device  120 , so as to synchronize a piconet clock utilized among the first member device  120  and other Bluetooth devices. In this situation, the second control circuit  135  is further arranged to operably control the second member device  130  to act as a Bluetooth Peripheral in the Bluetooth piconet, and to operably adjust the clock signals employed by the second member device  130 , so as to synchronize the piconet clock utilized between the second member device  130  and the first member device  120 . 
     In this embodiment, each of the Bluetooth host device  110 , the first member device  120 , and the second member device  130  supports the BLE Audio technology. In this situation, the processing circuit  117  of the Bluetooth host device  110  is further arranged to operably generate audio data complying with related specifications of the BLE Audio technology (hereinafter referred to as BLE audio data), and to operably utilize the host-side communication circuit  111  transmit the BLE audio data to all member devices in the Bluetooth device set  102 . The first control circuit  125  of the first member device  120  is further arranged to operably utilize the first audio processing circuit  127  to process the BLE audio data transmitted from the Bluetooth host device  110 , and to operably instruct the first audio processing circuit  127  to control the first audio playback circuit  162  to playback the contents of the BLE audio data. Similarly, the second control circuit  135  of the second member device  130  is further arranged to operably utilize the second audio processing circuit  137  to process the BLE audio data transmitted from the Bluetooth host device  110 , and to operably instruct the second audio processing circuit  137  to control the second audio playback circuit  172  to playback the contents of the BLE audio data. 
     In some embodiments, the host-side communication circuit  111  of the Bluetooth host device  110  is further arranged to operably adopt various wired network transmission technologies or various Radio Access Technologies (RATs) to receive the voice data transmitted from a remote device (not shown in figures) through various networks (e.g., Internet, mobile communication networks, or various private networks). The processing circuit  117  is arranged to operably decode the voice data received by the host-side communication circuit  111 , and arranged to operably utilize the host-side communication circuit  111  to transmit decoded voice data to the first member device  120  and/or the second member device  130  in the Bluetooth device set  102  in the form of Bluetooth packets, and to operably instruct the first member device  120  and/or the second member device  130  to utilize the first audio playback circuit  162  and/or the second audio playback circuit  172  to playback the contents of the voice data. 
     The aforementioned RAT may be various 2nd Generation (2G) mobile communication technologies, various 3rd Generation (3G) mobile communication technologies, various 4th Generation (4G) mobile communication technologies, various 5th Generation (5G) mobile communication technologies, various wireless networking technologies specified by the IEEE 802.11 series standards, various Internet-of-Thing (IoT) communication technologies, various Narrow Band Internet of Thing (NB-IoT) communication technologies, various Vehicle-to-Vehicle communication technologies, various Vehicle-to-Everything (V2X) communication technologies, various satellite communication technologies, various wireless communication technologies proposed by other standard setting organizations, or the like. 
     On the other hand, the first member device  120  and/or the second member device  130  may utilize the first voice receiving circuit  164  and/or the second voice receiving circuit  174  to receive the user&#39;s voice, and may utilize the first audio processing circuit  127  and/or the second audio processing circuit  137  to generate related sound data. The first member device  120  and/or the second member device  130  may further utilize the first communication circuit  121  and/or the second communication circuit  131  to transmit the aforementioned sound data to the Bluetooth host device  110 . In this situation, the processing circuit  117  of the Bluetooth host device  110  may further adopt the aforementioned wired network transmission technologies or RATs to transmit the sound data generated by the Bluetooth device set  102  to the remote device through various appropriate networks. 
     As a result, the user is enabled to utilize the cooperation of the Bluetooth host device  110  and the Bluetooth device set  102  to realize voice communication with the remote device. 
     In practice, the host-side communication circuit  111  in the Bluetooth host device  110  may be realized with appropriate wireless transceiver circuits supporting the Bluetooth communication protocol of the Bluetooth Core Specification Version 5.2 or a newer version. Alternatively, the host-side communication circuit  111  may be realized with various hybrid communication circuits supporting above Bluetooth communication protocol and also supporting the aforementioned wired network transmission technologies or RATs. If needed, the host-side communication circuit  111  may be coupled with an additional antenna (not shown in figures). 
     The input circuit  113  may be realized with various appropriate circuits capable of receiving the commands issued by the user, such as a keyboard, a mouse, a touch screen, a voice activated device, a gesture sensing device, or a hybrid of the above various devices. 
     The host-side cypher key generation circuit  115  may be realized with various digital computing circuits, microprocessors, security modules, or Application Specific Integrated Circuits (ASICs) having cypher key computing capabilities. 
     The processing circuit  117  may be realized with an appropriate packet demodulation circuit, a digital computing circuit, a microprocessor, an ASIC, a single processor module, a combination of multiple processor modules, a single computer system, a combination of multiple computer systems, a single server, a combination of multiple servers, or a cloud computing system having appropriate computing capabilities and capable of parsing and generating Bluetooth packets adopting the BLE Audio technology specified by the Bluetooth Core Specification Version 5.2 or newer versions. 
     In practical applications, different functional blocks of the aforementioned Bluetooth host device  110  may be realized with separate circuits or may be integrated into a single IC chip or a single device. 
     For example, the input circuit  113  and/or the host-side cypher key generation circuit  115  may be integrated into the processing circuit  117 . For another example, the input circuit  113  and the display device  150  may be integrated into a single touch screen. 
     Alternatively, all functional blocks of the Bluetooth host device  110  may be integrated into a single IC chip, a mobile communication device (e.g., a cell phone), a wearable device, a tablet computer, a notebook computer, a desktop computer, an audio broadcast system, a voice guidance system, a voice broadcasting system, a vehicular communication device, a satellite communication device, a smart TC, a Bluetooth smart speaker, or the like. 
     In practice, each of the first communication circuit  121  and the second communication circuit  131  in the Bluetooth device set  102  may be realized with an appropriate Bluetooth communication circuit capable of supporting the Bluetooth communication protocol of the Bluetooth Core Specification Version 5.2 or newer versions. If needed, the first communication circuit  121  and the second communication circuit  131  may be respectively coupled with additional antennas (not shown in figures). 
     Each of the first cypher key generation circuit  123  and the second cypher key generation circuit  133  may be realized with appropriate digital computing circuits, microprocessors, security modules, or ASICs having cypher key computing capabilities. 
     Each of the first control circuit  125  and the second control circuit  135  may be realized with an appropriate packet demodulation circuit, a digital computing circuit, a microprocessor, a single processor module, a combination of multiple processor modules, or an ASIC having appropriate computing capabilities and capable of parsing and generating Bluetooth packets adopting the BLE Audio technology specified by the Bluetooth Core Specification Version 5.2 or newer versions. 
     In some embodiments, the aforementioned first communication circuit  121  and second communication circuit  131  may be realized with appropriate Bluetooth transmission circuits that also support the Bluetooth communication protocol of earlier Bluetooth versions (e.g., Bluetooth 2.0, Bluetooth 3.0, Bluetooth 4.0, Bluetooth 4.2, or the like). In this situation, the aforementioned first control circuit  125  and second control circuit  135  should be designed to be able to parse and generate Bluetooth packets defined by the Bluetooth communication protocol of earlier Bluetooth versions. 
     Each of the first audio processing circuit  127  and the second audio processing circuit  137  may be realized with digital computing circuits, microprocessors, ASICs, or digital-to-analog converters (DACs) capable of conducting various encoding/decoding processing and/or data format conversion on audio data. 
     In some embodiments, the first audio processing circuit  127  and the second audio processing circuit  137  may be respectively integrated into the first control circuit  125  and the second control circuit  135 . 
     Different functional blocks of the aforementioned first member device  120  may be realized with separate circuits or may be integrated into a single IC chip, a single wearable Bluetooth device, or a single Bluetooth speaker. 
     Similarly, different functional blocks of the aforementioned second member device  130  may be realized with separate circuits or may be integrated into a single IC chip, a single wearable Bluetooth device, or a single Bluetooth speaker. 
     In addition, each of the first audio playback circuit  162  and the second audio playback circuit  172  may be realized with various appropriate circuits capable of receiving and playbacking audio data, such as various types of speakers. Each of the first voice receiving circuit  164  and the second voice receiving circuit  17  may be realized with various appropriate circuits capable of receiving sound and converting sound into corresponding audio signals, such as various types of microphones. 
     In some embodiments, the first member device  120 , the first audio playback circuit  162 , and the first voice receiving circuit  164  may be integrated into a single device (e.g., a wearable Bluetooth device or a Bluetooth speaker). Similarly, the second member device  130 , the second audio playback circuit  172 , and the second voice receiving circuit  174  may be integrated into a single device (e.g., a wearable Bluetooth device or a Bluetooth speaker). 
     The main circuit structure and implementations of other member devices (e.g., the third member device  140 ), other audio playback circuits (e.g., the third audio playback circuit  182 ), and other voice receiving circuits (e.g., the third voice receiving circuit  184 ) in the Bluetooth device set  102 , may be similar to the aforementioned corresponding member devices/corresponding circuits. But different additional circuit components may be provided in different member devices, different audio playback circuits, and/or different voice receiving circuits. The circuit structure of all member devices is not required to be exactly identical with each other. The circuit structure of all audio playback circuits is not required to be exactly identical with each other. The circuit structure of all voice receiving circuits are not required to be exactly identical with each other. 
     When the Bluetooth host device  110  and the member devices in the Bluetooth device set  102  support the BLE Audio technology, the user may utilize the Bluetooth communication system  100  to conduct various audio playback operations adopting the BLE Audio technology to reduce the power consumption of the Bluetooth communication system  100  while improving the overall audio playback quality. 
     As described previously, when a traditional Bluetooth device set that supports the BLE Audio technology wants to connect with a traditional Bluetooth host device, the traditional Bluetooth host device has to negotiate with individual member devices in the traditional Bluetooth device set one by one regarding the relevant parameters for generating cypher keys. Therefore, it will take a lengthy time for the traditional Bluetooth host device to respectively conduct Bluetooth pairing with respective member devices in the traditional Bluetooth device set. 
     In order to solve the problem that the efficiency of pairing between the traditional Bluetooth host device and different member devices in the traditional Bluetooth device set is too low, the Bluetooth host device  110  and the Bluetooth device set  102  in the disclosed Bluetooth communication system  100  will adopt different approaches to improve the generation efficiency of related cypher keys. 
     The operations of the Bluetooth communication system  100  will be further described in the following by reference to  FIG. 2  and  FIG. 3 .  FIG. 2  and  FIG. 3  collectively show a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a first embodiment of the present disclosure. 
     In the flowchart of  FIG. 2  and  FIG. 3 , operations within a column under the name of a specific device are operations to be performed by the specific device. For example, operations within a column under the label “Bluetooth host device” are operations to be performed by the Bluetooth host device  110 ; operations within a column under the label “first member device” are operations to be performed by the first member device  120 ; operations within a column under the label “second member device” are operations to be performed by the second member device  130 ; and so forth. The same analogous arrangement also applies to the subsequent flowcharts. 
     When the user wants to utilize the Bluetooth communication system  100  to playback various audio data adopting the BLE Audio technology, the Bluetooth host device  110  should be paired with respective member devices in the Bluetooth device set  102  in advance. 
     In this situation, the processing circuit  117  of the Bluetooth host device  110  may generate a Bluetooth inquiry request containing a device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ), and may utilize the host-side communication circuit  111  to transmit the Bluetooth inquiry request to other nearby Bluetooth devices, and then wait for responses from the member devices of the Bluetooth device set  102 . In practice, the processing circuit  117  may also fill in other data or messages in the above Bluetooth inquiry request depending on the requirement of the function design. 
     Alternatively, the processing circuit  117  may control the host-side communication circuit  111  to operate in a predetermined receiving mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs. For example, the predetermined receiving mode may be an operating mode capable of receiving various Bluetooth advertising packets, such as an LE Extended Passive Scan mode, an LE Extended Active Scan mode, an LE Extended Initiator mode, or a Periodic Scanning. 
     On the other hand, all member devices in the Bluetooth device set  102  may enter a predetermined transmitting mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs, or may operate in the predetermined transmitting mode after receiving the Bluetooth inquiry request generated by the Bluetooth host device  110 . The predetermined transmitting mode may be various operating modes capable of transmitting various Bluetooth advertising packets and/or Bluetooth protocol data units (PDUs). For example, the predetermined transmitting mode may be an Advertising mode, a Scannable mode, a Connectable mode, a Non-connectable mode, a Non-scannable mode, a Periodic Advertising mode, an LE Extended Advertising mode, or an LE Periodic Advertising mode. 
     The first member device  120  may perform the operation  202  of  FIG. 2  after entering the predetermined transmitting mode. 
     In the operation  202 , the first control circuit  125  may generate one or more target Bluetooth packets, wherein the one or more target Bluetooth packets contain a device information of the first member device  120  (e.g., a Bluetooth device address of the first member device  120 ) and an auto-pair request that can be utilized to identify the brand, the vendor, the circuit model, and/or the firmware version of the first member device  120  or the first control circuit  125 . The first control circuit  125  may define the content and format of the auto-pair request by itself according to preset rules. The first control circuit  125  may insert the auto-pair request and the device information of the first member device  120  into one or more specific fields of a single target Bluetooth packet, or may insert them into specific fields of multiple target Bluetooth packets in a distributed manner. In operations, the first control circuit  125  may utilize predetermined Bluetooth advertising packets to be the above target Bluetooth packets. 
     For example, the one or more target Bluetooth packets mentioned in the operation  202  may be one or more auxiliary advertising indication (AUX_ADV_IND) packets, or may be a group of packets formed by one or more extended advertising indication (ADV_EXT_IND) packets and one or more auxiliary advertising indication (AUX_ADV_IND) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be one or more auxiliary chain indication (AUX_CHAIN_IND) packets, or may be a group of packets formed by one or more extended advertising indication (ADV_EXT_IND) packets, one or more auxiliary advertising indication (AUX_ADV_IND) packets, and one or more auxiliary chain indication (AUX_CHAIN_IND) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be one or more auxiliary scan response (AUX_SCAN_RSP) packets, or may be a group of packets formed by one or more extended advertising indication (ADV_EXT_IND) packets, one or more auxiliary advertising indication (AUX_ADV_IND) packets, and one or more auxiliary scan response (AUX_SCAN_RSP) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be a group of packets formed by one or more auxiliary scan response (AUX_SCAN_RSP) packets, and one or more auxiliary chain indication (AUX_CHAIN_IND) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be a group of packets formed by one or more extended advertising indication (ADV_EXT_IND) packets, one or more auxiliary advertising indication (AUX_ADV_IND) packets, one or more auxiliary scan response (AUX_SCAN_RSP) packets, and one or more auxiliary chain indication (AUX_CHAIN_IND) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be one or more auxiliary synchronous indication (AUX_SYNC_IND) packets, or may be a group of packets formed by one or more extended advertising indication (ADV_EXT_IND) packets, one or more auxiliary advertising indication (AUX_ADV_IND) packets, and one or more auxiliary synchronous indication (AUX_SYNC_IND) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be one or more advertising indication (ADV_IND) packets, one or more non-connectable advertising indication (ADV_NONCONN_IND) packets, or one or more discoverable advertisement indication (ADV_DISCOVER_IND) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be a group of packets formed by one or more advertising indication (ADV_IND) packets, and one or more non-connectable advertising indication (ADV_NONCONN_IND) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be a group of packets formed by one or more advertising indication (ADV_IND) packets, and one or more discoverable advertisement indication (ADV_DISCOVER_IND) packets. 
     For another example, the aforementioned one or more target Bluetooth packets may be a group of packets formed by one or more advertising indication (ADV_IND) packets, one or more non-connectable advertising indication (ADV_NONCONN_IND) packets, and one or more discoverable advertisement indication (ADV_DISCOVER_IND) packets. 
     In the operation  204 , the first control circuit  125  may utilize the first communication circuit  121  to transmit the aforementioned one or more target Bluetooth packets to the Bluetooth host device  110 . 
     In the operation  206 , the host-side communication circuit  111  of the Bluetooth host device  110  may receive the one or more target Bluetooth packets. 
     In the operation  208 , the processing circuit  117  of the Bluetooth host device  110  may parse the one or more target Bluetooth packets to acquire the auto-pair request and the device information of the first member device  120  transmitted from the first member device  120 . Then, the processing circuit  117  may inspect the format and content of the auto-pair request to determine whether the brand, the vendor, the circuit model, and/or the firmware version of the first member device  120  or the first control circuit  125  matches a predetermined condition (e.g., whether it or they correspond to the brand, the vendor, the circuit model, and/or the firmware version of the Bluetooth host device  110  and/or the processing circuit  117 ). For example, the processing circuit  117  may inspect whether the format of the auto-pair request matches a predetermined feature or not, or whether the auto-pair request contains a predetermined content or not. 
     In one embodiment, if the format of the auto-pair request matches the predetermined feature, and/or the auto-pair request contains the predetermined content, then the processing circuit  117  may determine that the brand, the vendor, the circuit model, and/or the firmware version of the first member device  120  or the first control circuit  125  matches the predetermined condition. In this situation, the processing circuit  117  may identify the first member device  120  as a first privileged device according to the aforementioned auto-pair request, and then perform the operation  210 . 
     In this embodiment, when the first member device  120  is identified as a privileged device by the processing circuit  117 , it means that when the Bluetooth host device  110  and the first member device  120  conduct a Bluetooth pairing procedure, the Bluetooth host device  110  and the first member device  120  can skip many traditional key parameter negotiation steps, and are permitted to directly adopt a pre-defined simplified method to generate the cypher keys. Relevant operations will be further described in the operation  210  through the operation  216 . 
     On the contrary, if the format of the auto-pair request does not match the predetermined feature, and the auto-pair request does not contain predetermined contents, then the processing circuit  117  may determine that the brand, the vendor, the circuit model, and/or the firmware version of the first member device  120  or the first control circuit  125  does not match the predetermined condition. In this situation, the processing circuit  117  may identify the first member device  120  as an ordinary Bluetooth device, and then adopt various existing approaches to conduct Bluetooth pairing with the first member device  120  so as to generate related cypher keys. 
     In the operation  210 , the processing circuit  117  may establish a connection with the first member device  120  through the host-side communication circuit  111 , and may decide a first parameter P 1  and generate a first privileged pairing notice. In one embodiment, the processing circuit  117  may generate a first predetermined value, a first random value, a first predetermined address, a first random address, a first predetermined string, a first random string, a first predetermined token, a first random token, or a first access address corresponding to the first member device  120  to be the first parameter P 1 . In another embodiment, the processing circuit  117  may opt to use the content of a predetermined field in a certain Bluetooth packet transmitted from the first member device  120  to the Bluetooth host device  110  to be the first parameter P 1 , or may instead opt to use the content of a predetermined field in a certain Bluetooth packet transmitted from the Bluetooth host device  110  to the first member device  120  to be the first parameter P 1 . For example, the processing circuit  117  may opt to use an initial value of a cyclic redundancy check (CRCInit), a window size (WinSize), a window offset (WinOffset), a connection event interval (Connection Interval), a slave latency, a timeout value, a channel map, a hop, or a sleep clock accuracy (SCA) in a connection indication (Connect_IND) packet or in an auxiliary connection request (AUX_Connect_REQ) packet generated by the processing circuit  117  to be the first parameter P 1 . For another example, the processing circuit  117  may opt to use the value of the cyclic redundancy check (CRC) in the aforementioned connection indication (Connect_IND) packet or auxiliary connection request (AUX_Connect_REQ) packet to be the first parameter P 1 . For another example, the processing circuit  117  may opt to use the value of the cyclic redundancy check (CRC) in an auxiliary connection response (AUX_Connect_RSP) packet or in a specific Bluetooth advertising packet generated by the first member device  120  to be the first parameter P 1 . The processing circuit  117  may also transmit the first privileged pairing notice to the first member device  120  through the host-side communication circuit  111  in the operation  210 . Additionally, in the operation  210 , the processing circuit  117  may also transmit the first parameter P 1  or a first field indication to the first member device  120  through the host-side communication circuit  111 , wherein the first field indication is utilized for indicating a specific packet field whose content is to be utilized as the first parameter P 1 . 
     In this situation, the first communication circuit  121  of the first member device  120  may perform the operation  212  to receive the first privileged pairing notice transmitted from the Bluetooth host device  110 . In addition, the first communication circuit  121  may also receive the first parameter P 1  or a related first field indication transmitted from the Bluetooth host device  110  in the operation  212 , so that the first control circuit  125  is enabled to learn the first parameter P 1  decided by the Bluetooth host device  110  accordingly. 
     In the operation  214 , the processing circuit  117  of the Bluetooth host device  110  may generate a first cypher key Key- 1  required for conducting subsequent Bluetooth data transmissions with the first member device  120  according to the first parameter P 1 . For example, the processing circuit  117  may execute a predetermined cypher key algorithm to generate the first cypher key Key- 1  according to the first parameter P 1  and the device information of the Bluetooth host device  110 . For another example, the processing circuit  117  may execute the aforementioned predetermined cypher key algorithm to generate the first cypher key Key- 1  according to the first parameter P 1 , the device information of the Bluetooth host device  110 , and the device information of the first member device  120 . 
     In the operation  216 , the first control circuit  125  of the first member device  120  may generate a second cypher key Key- 2  required for conducting subsequent Bluetooth data transmissions with the Bluetooth host device  110  according to the first parameter P 1 . In other words, the second cypher key Key- 2  generated by the first control circuit  125  and the first cypher key Key- 1  generated by the processing circuit  117  will correspond to each other. For example, the first control circuit  125  may execute the aforementioned predetermined cypher key algorithm to generate the second cypher key Key- 2  according to the first parameter P 1  and the device information of the first member device  120 . For another example, the first control circuit  125  may execute the aforementioned predetermined cypher key algorithm to generate the second cypher key Key- 2  according to the first parameter P 1 , the device information of the first member device  120 , and the device information of the Bluetooth host device  110 . 
     In other words, after the first member device  120  is identified as the first privileged device by the Bluetooth host device  110 , the Bluetooth host device  110  and the first member device  120  can omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding first cypher key Key- 1  and second cypher key Key- 2 . That is, the Bluetooth host device  110  can directly generate the first cypher key Key- 1  based on the first parameter P 1  decided by the Bluetooth host device  110  while the first member device  120  can directly generate the second cypher key Key- 2  based on the first parameter P 1  decided by the Bluetooth host device  110 . As a result, it can significantly reduce the required time for generating the first cypher key Key- 1  and the second cypher key Key- 2 . 
     In the operation  218 , the processing circuit  117  of the Bluetooth host device  110  may use the first cypher key Key- 1  to conduct Bluetooth data transmissions with the first member device  120  through the host-side communication circuit  111 . 
     In the operation  220 , the first control circuit  125  of the first member device  120  may use the second cypher key Key- 2  to conduct Bluetooth data transmissions with the Bluetooth host device  110  through the first communication circuit  121 . 
     For example, in the embodiments where both the Bluetooth host device  110  and the first member device  120  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the first member device  120 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110  and the first member device  120  to thereby extend the serving time of the Bluetooth host device  110  and the first member device  120 , but also effectively improves the overall quality of the audio playback operations. 
     As shown in  FIG. 3 , after the second cypher key Key- 2  is generated by the first control circuit  125 , the first control circuit  125  may further perform the operation  302  to utilize the first communication circuit  121  to transmit a device set identification information Set-ID corresponding to the Bluetooth device set  102 . For example, the first control circuit  125  may utilize a Set Identity Resolving Key (SIRK) of the Bluetooth device set  102  to be the device set identification information Set-ID of the Bluetooth device set  102 . 
     In this situation, the host-side communication circuit  111  of the Bluetooth host device  110  may perform the operation  304  to receive the device set identification information Set-ID transmitted from the first member device  120 . 
     In operations, the first control circuit  125  of the first member device  120  may generate a resolvable set identifier (RSI) corresponding to the first member device  120  at an appropriate time point (e.g., at any time point between the operation  202  and the operation  220 , or at a certain time point before the operation  202 ). For example, the first control circuit  125  may perform a predetermined target algorithm according to the device set identification information Set-ID of the Bluetooth device set  102  to generate a random address, and utilize the random address to be a resolvable set identifier RSI- 1  corresponding to the first member device  120 . 
     In practice, the first control circuit  125  may utilize the first communication circuit  121  to transmit the resolvable set identifier RSI- 1  corresponding to the first member device  120  to the Bluetooth host device  110  at any time point after the operation  202 . 
     Alternatively, the first control circuit  125  may also insert the resolvable set identifier RSI- 1  corresponding to the first member device  120  into the one or more target Bluetooth packets to be transmitted to the Bluetooth host device  110  in the operation  202 . As a result, the Bluetooth host device  110  is enabled to receive the resolvable set identifier RSI- 1  corresponding to the first member device  120  in the operation  206 . 
     Similarly, the second control circuit  135  of the second member device  130  may perform the operation  306  of  FIG. 3  at any appropriate time point to generate a resolvable set identifier RSI- 2  corresponding to the second member device  130 . For example, the second control circuit  135  may perform the aforementioned target algorithm according to the device set identification information Set-ID of the Bluetooth device set  102  to generate a random address, and utilize the random address to be the resolvable set identifier RSI- 2  corresponding to the second member device  130 . In practice, the second control circuit  135  may perform the operation  306  at any time point between the operation  202  and the operation  220 , or at a certain time point before the operation  202 . 
     As described previously, all member devices in the Bluetooth device set  102  may operate in a predetermined transmitting mode. The second member device  130  may perform the operation  308  of  FIG. 3  during a time period while the second member device  130  operates in the predetermined transmitting mode. 
     In the operation  308 , the second control circuit  135  may utilize the second communication circuit  131  to transmit a device information of the second member device  130  (e.g., a Bluetooth device address of the second member device  130 ) and the resolvable set identifier RSI- 2  to the Bluetooth host device  110 . In operations, the second control circuit  135  may generate one or more target Bluetooth packets containing the device information of the second member device  130  and the resolvable set identifier RSI- 2  by adopting the approach described in the aforementioned operation  202 . For example, the second control circuit  135  may insert the resolvable set identifier RSI- 2  and the device information of the second member device  130  into one or more specific fields of a single target Bluetooth packet, or may insert them into specific fields of multiple target Bluetooth packets in a distributed manner. Then, the second control circuit  135  may utilize the second communication circuit  131  to transmit the one or more target Bluetooth packets to the Bluetooth host device  110 . 
     The type of the target Bluetooth packets referred to in the operation  308  may be the same as the type of the target Bluetooth packets referred to in the aforementioned operation  202 . For the sake of brevity, the descriptions will not be repeated here. 
     In this situation, the host-side communication circuit  111  of the Bluetooth host device  110  may perform the operation  310  to receive the one or more target Bluetooth packets transmitted from the second member device  130 . The processing circuit  117  may parse the one or more target Bluetooth packets to acquire the device information of the second member device  130  and the resolvable set identifier RSI- 2 . 
     Then, in the operation  312 , the processing circuit  117  may inspect the resolvable set identifier RSI- 2  of the second member device  130  according to the device set identification information Set-ID transmitted from the first member device  120 , so as to determine whether the second member device  130  belongs to the Bluetooth device set  102  or not. For example, in this embodiment, the processing circuit  117  may inspect whether the resolvable set identifier RSI- 2  is a random address calculated based on the device set identification information Set-ID or not. 
     If the processing circuit  117  determines that the resolvable set identifier RSI- 2  is a random address generated based on the device set identification information Set-ID, then the processing circuit  117  may determine that the second member device  130  belongs to the Bluetooth device set  102 . In this situation, the processing circuit  117  may identify the second member device  130  as a member device of the Bluetooth device set  102  in the operation  312  according to the device set identification information Set-ID and the resolvable set identifier RSI- 2 , and then perform the operation  314 . 
     In this embodiment, when the second member device  130  is identified as a member device of the Bluetooth device set  102  by the processing circuit  117 , it means that when the Bluetooth host device  110  and the second member device  130  conduct a Bluetooth pairing procedure, the Bluetooth host device  110  and the second member device  130  can skip many traditional key parameter negotiation steps, and are permitted to directly adopt a pre-defined simplified method to generate the cypher keys. Relevant operations will be further described in the operation  314  through the operation  320 . 
     On the contrary, if the processing circuit  117  determines that the resolvable set identifier RSI- 2  is not a random address generated based on the device set identification information Set-ID, then the processing circuit  117  may determine that the second member device  130  does not belong to the Bluetooth device set  102 . In this situation, the processing circuit  117  may identify the second member device  130  as an ordinary Bluetooth device, and then adopt various existing approaches to conduct Bluetooth pairing with the second member device  130  so as to generate related cypher keys. 
     In the operation  314 , the processing circuit  117  may establish a connection with the second member device  130  through the host-side communication circuit  111 , and may decide a second parameter P 2  and generate a second privileged pairing notice. In one embodiment, the processing circuit  117  may generate a second predetermined value, a second random value, a second predetermined address, a second random address, a second predetermined string, a second random string, a second predetermined token, a second random token, or a second access address corresponding to the second member device  130  to be the second parameter P 2 . In another embodiment, the processing circuit  117  may opt to use the content of a predetermined field in a certain Bluetooth packet transmitted from the second member device  130  to the Bluetooth host device  110  to be the second parameter P 2 , or may instead opt to use the content of a predetermined field in a certain Bluetooth packet transmitted from the Bluetooth host device  110  to the second member device  130  to be the second parameter P 2 . For example, the processing circuit  117  may opt to use an initial value of a cyclic redundancy check (CRCInit), a window size (WinSize), a window offset (WinOffset), a connection event interval (Connection Interval), a slave latency, a timeout value, a channel map, a hop, or a sleep clock accuracy (SCA) in a connection indication (Connect_IND) packet or in an auxiliary connection request (AUX_Connect_REQ) packet generated by the processing circuit  117  to be the second parameter P 2 . For another example, the processing circuit  117  may opt to use the value of the cyclic redundancy check (CRC) in the aforementioned connection indication (Connect_IND) packet or auxiliary connection request (AUX_Connect_REQ) packet to be the second parameter P 2 . For another example, the processing circuit  117  may opt to use the value of the cyclic redundancy check (CRC) in an auxiliary connection response (AUX_Connect_RSP) packet or in a specific Bluetooth advertising packet generated by the second member device  130  to be the second parameter P 2 . The processing circuit  117  may also transmit the second privileged pairing notice to the second member device  130  through the host-side communication circuit  111  in the operation  314 . Additionally, in the operation  314 , the processing circuit  117  may also transmit the second parameter P 2  or a second field indication to the second member device  130  through the host-side communication circuit  111 , wherein the second field indication is utilized for indicating a specific packet field whose content is to be utilized as the second parameter P 2 . In practice, the second parameter P 2  may be identical to the first parameter P 1 , or may be different from the first parameter P 1 . 
     In this situation, the second communication circuit  131  of the second member device  130  may perform the operation  316  to receive the second privileged pairing notice transmitted from the Bluetooth host device  110 . In addition, the second communication circuit  131  may also receive the second parameter P 2  or a related second field indication transmitted from the Bluetooth host device  110  in the operation  316 , so that the second control circuit  135  is enabled to learn the second parameter P 2  decided by the Bluetooth host device  110  accordingly. 
     In the operation  318 , the processing circuit  117  of the Bluetooth host device  110  may generate a third cypher key Key- 3  required for conducting subsequent Bluetooth data transmissions with the second member device  130  according to the second parameter P 2 . For example, the processing circuit  117  may execute a predetermined cypher key algorithm according to the second parameter P 2  and the device information of the Bluetooth host device  110  to generate the third cypher key Key- 3 . For another example, the processing circuit  117  may execute the aforementioned predetermined cypher key algorithm according to the second parameter P 2 , the device information of the second member device  130 , and the device information of the Bluetooth host device  110  to generate the third cypher key Key- 3 . 
     In the operation  320 , the second control circuit  135  of the second member device  130  may generate a fourth cypher key Key- 4  required for conducting subsequent Bluetooth data transmissions with the Bluetooth host device  110  according to the second parameter P 2 . In other words, the fourth cypher key Key- 4  generated by the second control circuit  135  and the third cypher key Key- 3  generated by the processing circuit  117  will correspond to each other. For example, the second control circuit  135  may generate the aforementioned predetermined cypher key algorithm according to the second parameter P 2  and the device information of the second member device  130  to generate the fourth cypher key Key- 4 . For another example, the second control circuit  135  may execute the aforementioned predetermined cypher key algorithm according to the second parameter P 2 , the device information of the second member device  130 , and the device information of the Bluetooth host device  110  to generate the fourth cypher key Key- 4 . 
     In other words, after the second member device  130  is identified as a member device of the Bluetooth device set  102  by the Bluetooth host device  110 , the Bluetooth host device  110  and the second member device  130  may omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding third cypher key Key- 3  and fourth cypher key Key- 4 . That is, the Bluetooth host device  110  can directly generate the third cypher key Key- 3  based on the second parameter P 2  decided by the Bluetooth host device  110  while the second member device  130  can directly generate the fourth cypher key Key- 4  based on the second parameter P 2  decided by the Bluetooth host device  110 . As a result, it can significantly reduce the required time for generating the third cypher key Key- 3  and the fourth cypher key Key- 4 . 
     In the operation  322 , the processing circuit  117  of the Bluetooth host device  110  may use the third cypher key Key- 3  to conduct Bluetooth data transmissions with the second member device  130  through the host-side communication circuit  111 . 
     In the operation  324 , the second control circuit  135  of the second member device  130  may use the fourth cypher key Key- 4  to conduct Bluetooth data transmissions with the Bluetooth host device  110  through the second communication circuit  131 . 
     In practice, the Bluetooth host device  110  and other member devices in the Bluetooth device set  102  (e.g., the third member device  140 ) may establish connections according to the aforementioned interaction between the Bluetooth host device  110  and the second member device  130  to respectively generate required cypher keys for conducting subsequent Bluetooth data transmissions between both parties. 
     In the embodiments where both the Bluetooth host device  110  and the second member device  130  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the second member device  130 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110  and the second member device  130  to thereby extend the serving time of the Bluetooth host device  110  and the second member device  130 , but also effectively improves the overall quality of the audio playback operations. 
     In another embodiment, each of the other member devices in the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ) may generate one or more target Bluetooth packets containing the aforementioned auto-pair request, the device information of respective member device, and the resolvable set identifiers corresponding to respective member device, and transmit the one or more target Bluetooth packets to the to the Bluetooth host device  110  according to the approach adopted by the first member device  120  in the operation  202 . In other words, all member devices in the Bluetooth device set  102  may conduct the same operations in the operation  202 . 
     In this situation, the Bluetooth host device  110  may identify a member device that transmits the auto-pair request first as the first privileged device, and then conduct the simplified pairing procedure with the first privileged device first. Afterwards, the Bluetooth host device  110  may identify other member devices as member devices of the Bluetooth device set  102  according to the device set identification information Set-ID transmitted from the first privileged device and the resolvable set identifiers transmitted from other member devices, and then conduct the simplified pairing procedure with other member devices. 
     It can be appreciated from the foregoing descriptions of  FIG. 2  though  FIG. 3  that the Bluetooth host device  110  is enabled to determine whether the first member device  120  is a privileged device or not according to the auto-pair request transmitted from the first member device  120 . After the first member device  120  is identified as a privileged device by the Bluetooth host device  110 , the Bluetooth host device  110  and the first member device  120  can omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding first cypher key Key- 1  and second cypher key Key- 2 . That is, the Bluetooth host device  110  is enabled to generate the first cypher key Key- 1  by simply performing the aforementioned operation  210  and operation  214  while the first member device  120  is enabled to generate the second cypher key Key- 2  by simply performing the aforementioned operation  212  and operation  216 . As a result, it can significantly reduce the required time for generating the first cypher key Key- 1  and the second cypher key Key- 2 . 
     On the other hand, after the second member device  130  is identified as a member device of the Bluetooth device set  102  by the Bluetooth host device  110 , the Bluetooth host device  110  and the second member device  130  may omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding third cypher key Key- 3  and fourth cypher key Key- 4 . That is, the Bluetooth host device  110  is enabled to generate the third cypher key Key- 3  by simply performing the aforementioned operation  210  and operation  214  while the second member device  130  is enabled to generate the fourth cypher key Key- 4  by simply performing the aforementioned operation  212  and operation  216 . As a result, it can significantly reduce the required time for generating the third cypher key Key- 3  and the fourth cypher key Key- 4 . 
     Apparently, the method of above  FIG. 2  through  FIG. 3  can effectively simplify the Bluetooth pairing procedure between the Bluetooth host device  110  and respective member device of the Bluetooth device set  102 , thereby significantly reduce the required time for completing the pairing procedure between the Bluetooth host device  110  and the Bluetooth device set  102 . 
     According to the method described in  FIG. 2  through  FIG. 3 , the Bluetooth host device  110  and respective member devices of the Bluetooth device set  102  does not need to use any display device. Therefore, the display device  150  may be omitted, and the hardware structure, the weight, and the volume of respective member devices of the Bluetooth device set  102  can be greatly simplified. 
     Additionally, in the embodiments where the Bluetooth host device  110  and the member devices in the Bluetooth device set  102  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the member devices of the Bluetooth device set  102 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102  to thereby extend the serving time of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102 , but also effectively improves the overall quality of the audio playback operations. 
     Please refer to  FIG. 4  and  FIG. 5 , which collectively show a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a second embodiment of the present disclosure. 
     As described previously, when the user wants to utilize the Bluetooth device set  102  to playback audio data transmitted from the Bluetooth host device  110  by adopting the BLE Audio technology, the Bluetooth host device  110  should be paired with respective member devices in the Bluetooth device set  102  in advance. In this situation, as described above, the processing circuit  117  may generate a Bluetooth inquiry request containing the device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ), and may utilize the host-side communication circuit  111  to transmit the Bluetooth inquiry request to other nearby Bluetooth devices, and then wait for responses from the member devices of the Bluetooth device set  102 . 
     Alternatively, the processing circuit  117  may control the host-side communication circuit  111  to operate in the aforementioned predetermined receiving mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs. 
     On the other hand, all member devices in the Bluetooth device set  102  may enter a predetermined transmitting mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs, or may operate in the predetermined transmitting mode after receiving the Bluetooth inquiry request generated by the Bluetooth host device  110 . 
     The first member device  120  may perform the operation  402  of  FIG. 4  after entering the predetermined transmitting mode. 
     In the operation  402 , the first control circuit  125  may generate one or more target Bluetooth packets, wherein the one or more target Bluetooth packets containing a resolvable set identifier RSI- 1  corresponding to the first member device  120 , and a device information of the first member device  120  (e.g., a Bluetooth device address of the first member device  120 ). In operations, the first control circuit  125  of the first member device  120  may generate a resolvable set identifier RSI- 1  corresponding to the first member device  120  in the operation  402  or at a certain time point before the operation  402 . For example, the first control circuit  125  may perform a predetermined target algorithm according to the device set identification information Set-ID of the Bluetooth device set  102  to generate a random address, and utilize the random address as a resolvable set identifier RSI- 1  corresponding to the first member device  120 . The first control circuit  125  may insert the resolvable set identifier RSI- 1  and the device information of the first member device  120  into one or more specific fields of a single target Bluetooth packet, or may insert them into specific fields of multiple target Bluetooth packets in a distributed manner. 
     In practice, the first control circuit  125  may also insert the device set identification information Set-ID of the Bluetooth device set  102 , and/or the device information of other member devices in the Bluetooth device set  102  (e.g., the second member device  130  or the third member device  140 ) into the aforementioned one or more target Bluetooth packets. 
     The type of the target Bluetooth packets referred to in the operation  402  may be the same as the type of the target Bluetooth packets referred to in the aforementioned operation  202 . For the sake of brevity, the descriptions will not be repeated here. 
     In some embodiments, each of the other member devices in the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ) may generate one or more target Bluetooth packets containing the device information of respective member device and the resolvable set identifiers corresponding to respective member device, and transmit the one or more target Bluetooth packets to the to the Bluetooth host device  110  according to the approach adopted by the first member device  120  in the operation  402 . Similarly, each of the other member devices in the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ) may also insert the device set identification information Set-ID of the Bluetooth device set  102 , and/or the device information of other member devices of the Bluetooth device set  102  into the one or more target Bluetooth packets to be transmitted to the Bluetooth host device  110 . 
     In other words, all member devices in the Bluetooth device set  102  may conduct the same operations in the operation  402 . 
     In the operation  404 , the first control circuit  125  may utilize the first communication circuit  121  to transmit the aforementioned one or more target Bluetooth packets to the Bluetooth host device  110 . 
     In the operation  406 , the host-side communication circuit  111  of the Bluetooth host device  110  may receive the one or more target Bluetooth packets. 
     In the operation  408 , the processing circuit  117  of the Bluetooth host device  110  may parse the one or more target Bluetooth packets to acquire the resolvable set identifier RSI- 1  and the device information of the first member device  120  transmitted from the first member device  120 . Then, the processing circuit  117  may inspect the position of the resolvable set identifier RSI- 1  in the one or more target Bluetooth packets, to determine whether the brand, the vendor, the circuit model, and/or the firmware version of the first member device  120  or the first control circuit  125  matches a predetermined condition (e.g., whether it or they correspond to the brand, the vendor, the circuit model, and/or the firmware version of the Bluetooth host device  110  and/or the processing circuit  117 ). For example, the processing circuit  117  may inspect whether the position of the resolvable set identifier RSI- 1  in the one or more target Bluetooth packets matches a predetermined rule or not. 
     In one embodiment, if the position of the resolvable set identifier RSI- 1  in the one or more target Bluetooth packets matches the predetermined rule, then the processing circuit  117  may determine that the brand, the vendor, the circuit model, and/or the firmware version of the first member device  120  or the first control circuit  125  matches the predetermined condition. In this situation, the processing circuit  117  may identify the first member device  120  as a first privileged device according to the position of the resolvable set identifier RSI- 1 , and then perform the operation  410  of  FIG. 4 . 
     In this embodiment, when the first member device  120  is identified as a privileged device by the processing circuit  117 , it means that when the Bluetooth host device  110  and the first member device  120  conduct a Bluetooth pairing procedure, the Bluetooth host device  110  and the first member device  120  can skip many traditional key parameter negotiation steps, and my directly adopt a pre-defined simplified method to generate the cypher keys. The operations of this portion are substantially the same as that in the operation  210  through the operation  216  described previously. 
     On the contrary, if the position of the resolvable set identifier RSI- 1  in the one or more target Bluetooth packets does not match the predetermined rule, then the processing circuit  117  may determine that the brand, the vendor, the circuit model, and/or the firmware version of the first member device  120  or the first control circuit  125  does not match the predetermined condition. In this situation, the processing circuit  117  may identify the first member device  120  as an ordinary Bluetooth device, and then adopt various existing approaches to conduct Bluetooth pairing with the first member device  120  so as to generate related cypher keys. 
     In the operation  410 , the processing circuit  117  may generate a corresponding candidate device list according to messages transmitted from multiple nearby Bluetooth devices (e.g., responses to the Bluetooth inquiry request sent by the Bluetooth host device  110 ), and control the display device  150  to display the candidate device list. The processing circuit  117  may also conduct filtering on the device items to be displayed in the candidate device list in the operation  410 , and control the display device  150  to display a single device item for representing the entire Bluetooth device set  102  in the candidate device list, but does not simultaneously display a plurality of device items for respectively representing a plurality of member devices of the Bluetooth device set  102  in the candidate device list, so as to simplify the complexity of the user&#39;s manipulations during the Bluetooth pairing procedure. 
     As described previously, all member devices in the Bluetooth device set  102  may conduct the same operations in the operation  402 , that is, transmitting one or more target Bluetooth packets containing the device set identification information Set-ID of the Bluetooth device set  102 , their own device information, their own resolvable set identifier, and the device information of other member devices the to the Bluetooth host device  110 . In the aforementioned operation  410 , the processing circuit  117  may determine which member devices belong to the Bluetooth device set  102  just like the first member device  120  according to the contents of the target Bluetooth packets transmitted from different member devices. 
     For example, the processing circuit  117  may inspect the resolvable set identifier RSI- 2  provided by the second member device  130  according to the device set identification information Set-ID transmitted from the first member device  120  to determine whether the second member device  130  belongs to the Bluetooth device set  102  or not. In this embodiment, the processing circuit  117  may inspect whether the resolvable set identifier RSI- 2  is a random address generated based on the device set identification information Set-ID. If the processing circuit  117  determines that the resolvable set identifier RSI- 2  is a random address generated based on the device set identification information Set-ID, then the processing circuit  117  may determine that both the first member device  120  and the second member device  130  belong to the Bluetooth device set  102 . 
     For another example, the processing circuit  117  may compare the device information of the second member device  130  provided by the first member device  120  with the device information of the second member device  130  provided by the second member device  130  itself, so as to determine whether the second member device  130  belongs to the Bluetooth device set  102  or not. In this embodiment, if the device information of the second member device  130  provided by the first member device  120  is identical to the device information of the second member device  130  provided by the second member device  130  itself, then the processing circuit  117  may determine that both the first member device  120  and the second member device  130  belong to the Bluetooth device set  102 . 
     The user can know which Bluetooth devices can be paired with the Bluetooth host device  110  from the candidate device list displayed on the display device  150 . If the processing circuit  117  does not conduct filtering on the device items to be displayed in the candidate device list in the operation  410 , multiple device items respectively representing multiple member devices of the Bluetooth device set  102  may be shown in the candidate device list. Such a Bluetooth pairing method is likely to be too complicated (because the user has to select multiple member devices to be paired with the Bluetooth host device  110  one by one), and even makes it difficult for the user to find the correct pairing object. 
     From another aspect, the operation of filtering device items to be shown in the candidate device list conducted by the processing circuit  117  in the aforementioned operation  410  can simplify the complexity of user&#39;s manipulation during the Bluetooth pairing procedure, and can reduce the possibility of user&#39;s erroneous manipulation. 
     The user may manipulate the input circuit  113  to select the Bluetooth device set  102  as the object to be paired with the Bluetooth host device  110 . 
     In this situation, the input circuit  113  may perform the operation  412  to receive a selection command issued by the user, and transmit the selection command to the processing circuit  117 . 
     Then, the operations of the Bluetooth host device  110  in the following operation  210  and operation  214  of  FIG. 4  are the same as in the corresponding operations in  FIG. 2 , while the operations of the first member device  120  in the following operation  212  and operation  216  of  FIG. 4  are the same as the in corresponding operations in  FIG. 2 . For the sake of brevity, the descriptions will not be repeated here. 
     In other words, after the first member device  120  is identified as the first privileged device by the Bluetooth host device  110 , the Bluetooth host device  110  and the first member device  120  can omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding first cypher key Key- 1  and second cypher key Key- 2 . That is, the Bluetooth host device  110  is enabled to generate the first cypher key Key- 1  by simply performing the aforementioned operation  210  and operation  214  while the first member device  120  is enabled to generate the second cypher key Key- 2  by simply performing the aforementioned operation  212  and operation  216 . As a result, it can significantly reduce the required time for generating the first cypher key Key- 1  and the second cypher key Key- 2 . 
     As shown in  FIG. 5 , the Bluetooth host device  110  may perform the operation  218  of  FIG. 5  and subsequent operations after generating the first cypher key Key- 1 , and the first member device  120  may perform the operation  220  of  FIG. 5  and subsequent operations after generating the second cypher key Key- 2 . 
     Similarly, the second control circuit  135  of the second member device  130  may perform the operation  306  of  FIG. 5  at an appropriate time to generate a resolvable set identifier RSI- 2  corresponding to the second member device  130 . For example, the second control circuit  135  may perform the aforementioned target algorithm according to the device set identification information Set-ID of the Bluetooth device set  102  to generate a random address, and utilize the random address to be the resolvable set identifier RSI- 2  corresponding to the second member device  130 . In practice, the second control circuit  135  may perform the operation  306  of  FIG. 5  at any time point between the operation  402  of  FIG. 4  through the operation  220  of  FIG. 5 , or at a certain time point before the operation  402  of  FIG. 4 . 
     The operations of the Bluetooth communication system  100  in respective operations of  FIG. 5  are the same as the in corresponding operations of the aforementioned  FIG. 2  and  FIG. 3 . For the sake of brevity, the descriptions will not be repeated here. 
     In other words, in the embodiment of  FIG. 5 , after the second member device  130  is identified as a member device of the Bluetooth device set  102  by the Bluetooth host device  110 , the Bluetooth host device  110  and the second member device  130  may omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding third cypher key Key- 3  and fourth cypher key Key- 4 . That is, the Bluetooth host device  110  is enabled to generate the third cypher key Key- 3  by simply performing the aforementioned operation  210  and operation  214  while the second member device  130  is enabled to generate the fourth cypher key Key- 4  by simply performing the aforementioned operation  212  and operation  216 . As a result, it can significantly reduce the required time for generating the third cypher key Key- 3  and the fourth cypher key Key- 4 . 
     In practice, the Bluetooth host device  110  and other member devices in the Bluetooth device set  102  (e.g., the third member device  140 ) may establish connections according to the aforementioned interaction between the Bluetooth host device  110  and the second member device  130  to respectively generate required cypher keys for conducting subsequent Bluetooth data transmissions between both parties. 
     Similarly, in the embodiments where the Bluetooth host device  110 , the first member device  120 , and the second member device  130  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the first member device  120  and the second member device  130 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110 , the first member device  120 , and the second member device  130  to thereby extend the serving time of the Bluetooth host device  110 , the first member device  120 , and the second member device  130 , but also effectively improves the overall quality of the audio playback operations. 
     In another embodiment, other member devices in the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ) may generate one or more target Bluetooth packets containing the device information of respective member device and the resolvable set identifiers corresponding to respective member device, and transmit the one or more target Bluetooth packets to the to the Bluetooth host device  110  according to the approach adopted by the first member device  120  in the operation  402  of  FIG. 4 . In other words, all member devices in the Bluetooth device set  102  may conduct the same operations in the operation  402 . 
     In this situation, the Bluetooth host device  110  may identify a member device that transmits the auto-pair request first as the first privileged device, and then conduct the simplified pairing procedure with the first privileged device first. Afterwards, the Bluetooth host device  110  may identify other member devices as member devices of the Bluetooth device set  102  according to the device set identification information Set-ID transmitted from the first privileged device and the resolvable set identifiers transmitted from other member devices, and then conduct the simplified pairing procedure with other member devices. 
     It can be appreciated from the foregoing descriptions of  FIG. 2  though  FIG. 3  that the Bluetooth host device  110  is enabled to determine whether the first member device  120  is a privileged device or not according to the position of the resolvable set identifier RSI- 1  in the one or more target Bluetooth packets transmitted from the first member device  120 . After the first member device  120  is identified as a privileged device by the Bluetooth host device  110 , the Bluetooth host device  110  and the first member device  120  can omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding first cypher key Key- 1  and second cypher key Key- 2 . That is, the Bluetooth host device  110  is enabled to generate the first cypher key Key- 1  by simply performing the aforementioned operation  210  and operation  214  while the first member device  120  is enabled to generate the second cypher key Key- 2  by simply performing the aforementioned operation  212  and operation  216 . As a result, it can significantly reduce the required time for generating the first cypher key Key- 1  and the second cypher key Key- 2 . 
     On the other hand, after the second member device  130  is identified as a member device of the Bluetooth device set  102  by the Bluetooth host device  110 , the Bluetooth host device  110  and the second member device  130  may omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding third cypher key Key- 3  and fourth cypher key Key- 4 . That is, the Bluetooth host device  110  is enabled to generate the third cypher key Key- 3  by simply performing the aforementioned operation  210  and operation  214  while the second member device  130  is enabled to generate the fourth cypher key Key- 4  by simply performing the aforementioned operation  212  and operation  216 . As a result, it can significantly reduce the required time for generating the third cypher key Key- 3  and the fourth cypher key Key- 4 . 
     Apparently, the method of above  FIG. 4  through  FIG. 5  can also effectively simplify the Bluetooth pairing procedure between the Bluetooth host device  110  and respective member device of the Bluetooth device set  102 , thereby significantly reduce the required time for completing the pairing procedure between the Bluetooth host device  110  and the Bluetooth device set  102 . 
     Furthermore, the operation of filtering device items to be shown in the candidate device list conducted by the processing circuit  117  in the aforementioned operation  410  can simplify the complexity of user&#39;s manipulation during the Bluetooth pairing procedure, and also reduce the possibility of user&#39;s erroneous manipulation. 
     Additionally, in the embodiments where the Bluetooth host device  110  and the member devices in the Bluetooth device set  102  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the member devices of the Bluetooth device set  102 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102  to thereby extend the serving time of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102 , but also effectively improves the overall quality of the audio playback operations. 
     Please refer to  FIG. 6 , which shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a third embodiment of the present disclosure. 
     As described previously, when the Bluetooth host device  110  wants to conduct pairing with respective member devices of the Bluetooth device set  102 , the processing circuit  117  may generate a Bluetooth inquiry request containing the device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ), and may utilize the host-side communication circuit  111  to transmit the Bluetooth inquiry request to other nearby Bluetooth devices. 
     Alternatively, the processing circuit  117  may control the host-side communication circuit  111  to operate in the aforementioned predetermined receiving mode. 
     On the other hand, all member devices in the Bluetooth device set  102  may enter a predetermined transmitting mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs, or may operate in the predetermined transmitting mode after receiving the Bluetooth inquiry request generated by the Bluetooth host device  110 . 
     The first member device  120  may perform the operation  602  of  FIG. 6  after entering the predetermined transmitting mode. 
     In the operation  602 , the first control circuit  125  may utilize the first communication circuit  121  to transmit a device information of the first member device  120  (e.g., a Bluetooth device address of the first member device  120 ), and a device information of the second member device  130  (e.g., a Bluetooth device address of the second member device  130 ) to the Bluetooth host device  110 . For example, the first control circuit  125  may generate one or more target Bluetooth packets containing the device information of the first member device  120 , and the device information of the second member device  130 , and utilize the first communication circuit  121  to transmit the one or more target Bluetooth packets to the Bluetooth host device  110 . 
     The type of the target Bluetooth packets referred to in the operation  602  may be the same as the type of the target Bluetooth packets referred to in the aforementioned operation  202 . For the sake of brevity, the descriptions will not be repeated here. 
     In the operation  604 , the host-side communication circuit  111  of the Bluetooth host device  110  may receive the device information of the first member device  120  and the device information of the second member device  130  transmitted from the first member device  120 . 
     In practice, other member devices in the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ) may transmit their own device information and the device information of other member devices to the Bluetooth host device  110  according to the approach adopted by the first member device  120  in the operation  602 . 
     In other words, all member devices in the Bluetooth device set  102  may conduct the same operations in the operation  602 . In this situation, the host-side communication circuit  111  may receive the device information of multiple member devices transmitted from different member devices in the operation  604 . 
     In the operation  606 , the processing circuit  117  may generate a corresponding candidate device list according to messages transmitted from multiple nearby Bluetooth devices (e.g., responses to the Bluetooth inquiry request sent by the Bluetooth host device  110 ), and control the display device  150  to display the candidate device list. The processing circuit  117  may also filter the device items to be displayed in the candidate device list in the operation  606 , and control the display device  150  to display a single device item for representing the entire Bluetooth device set  102  in the candidate device list, but does not simultaneously display a plurality of device items for respectively representing a plurality of member devices of the Bluetooth device set  102  in the candidate device list, so as to simplify the complexity of the user&#39;s manipulations during the Bluetooth pairing procedure. 
     As described previously, all member devices in the Bluetooth device set  102  may conduct the same operations in the operation  602 , that is, transmitting their own device information and the device information of other member devices to the Bluetooth host device  110 . The processing circuit  117  may determine which member devices belong to the Bluetooth device set  102  just like the first member device  120  according to the device information of multiple member devices transmitted from different member devices in the operation  604 . 
     For example, the processing circuit  117  may compare the device information of the second member device  130  provided by the first member device  120  with the device information of the second member device  130  provided by the second member device  130  itself, to determine whether the second member device  130  belongs to the Bluetooth device set  102  or not. In this embodiment, if the device information of the second member device  130  provided by the first member device  120  is identical to the device information of the second member device  130  provided by the second member device  130  itself, then the processing circuit  117  may determine that both the first member device  120  and the second member device  130  belong to the Bluetooth device set  102 . 
     The user can know which Bluetooth devices can be paired with the Bluetooth host device  110  from the candidate device list displayed on the display device  150 . If the processing circuit  117  does not conduct filtering on the device items to be displayed in the candidate device list in the operation  606 , multiple device items respectively representing multiple member devices of the Bluetooth device set  102  may be shown in the candidate device list. Such a Bluetooth pairing method is likely to be too complicated (because the user has to select multiple member devices to be paired with the Bluetooth host device  110  one by one), and even makes it difficult for the user to find the correct pairing object. 
     From another aspect, the operation of filtering device items to be shown in the candidate device list conducted by the processing circuit  117  in the aforementioned operation  606  can simplify the complexity of user&#39;s manipulation during the Bluetooth pairing procedure, and can reduce the possibility of user&#39;s erroneous manipulation. 
     The user may manipulate the input circuit  113  to select the Bluetooth device set  102  as the object to be paired with the Bluetooth host device  110 . 
     In this situation, the input circuit  113  may perform the operation  608  to receive a selection command issued by the user, and transmit the selection command to the processing circuit  117 . 
     In the operation  610 , the processing circuit  117  may establish a connection with the first member device  120  through the host-side communication circuit  111  according to the selection command, and conduct a pairing procedure to generate a first cypher key Key- 1 . 
     In this situation, the first control circuit  125  may perform the operation  612  to establish a connection with the Bluetooth host device  110  through the first communication circuit  121 , and conduct the pairing procedure to generate a second cypher key Key- 2  corresponding to the first cypher key Key- 1 . 
     Please note that in the aforementioned operation  610  and operation  612 , the Bluetooth host device  110  and the first member device  120  may adopt various appropriate approach to conduct the Bluetooth pairing procedure, and are not restricted to follow the pairing approach adopted in the aforementioned embodiment of  FIG. 2  and  FIG. 4 . In addition, the Bluetooth host device  110  and the first member device  120  may adopt various appropriate approach to negotiate the parameters of key generation to respectively generate the first cypher key Key- 1  and the second cypher key Key- 2 , and are not restricted to follow the key generation mechanism adopted in the aforementioned embodiment of  FIG. 2  and  FIG. 4 . 
     As shown in  FIG. 6 , the processing circuit  117  of this embodiment further perform the operation  614  after generating the first cypher key Key- 1  to create a correlation between the second member device  130  and the first cypher key Key- 1 . 
     On the other hand, the first control circuit  125  may further perform the operation  616  after generating the second cypher key Key- 2  to utilize the first communication circuit  121  to transmit a device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ) and the second cypher key Key- 2  to the second member device  130 . 
     In this situation, the second communication circuit  131  of the second member device  130  may perform the operation  618  to receive the second cypher key Key- 2  and the device information of the Bluetooth host device  110  transmitted from the first member device  120 . 
     Then, the processing circuit  117  may perform the operation  620  to establish a connection with the second member device  130  through the host-side communication circuit  111 , and directly use the first cypher key Key- 1  to conduct Bluetooth data transmissions with the second member device  130 . 
     The second control circuit  135  may perform the operation  622  to establish a connection with the Bluetooth host device  110  through the second communication circuit  131  according to the device information of the Bluetooth host device  110 , and directly use the second cypher key Key- 2  to conduct Bluetooth data transmissions with the Bluetooth host device  110 . 
     In practice, the first control circuit  125  may adopt the aforementioned approach to transmit the aforementioned second cypher key Key- 2  to other member devices in the Bluetooth device set  102  (e.g., the third member device  140 ), so that other member devices in the Bluetooth device set  102  can directly use the second cypher key Key- 2  generated by the first member device  120  to conduct Bluetooth data transmissions with the Bluetooth host device  110 . 
     In the embodiments where the Bluetooth host device  110 , the first member device  120 , and the second member device  130  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the first member device  120  and the second member device  130 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110 , the first member device  120 , and the second member device  130  to thereby extend the serving time of the Bluetooth host device  110 , the first member device  120 , and the second member device  130 , but also effectively improves the overall quality of the audio playback operations. 
     In the above embodiment of  FIG. 6 , the first member device  120  transmits the device information of the first member device  120  and the device information of the second member device  130  to the Bluetooth host device  110  in the operation  602 . But this merely an exemplary embodiment, rather than a restriction to practical implementations. In practice, the first member device  120  may instead transmit the device information of the second member device  130  to the Bluetooth host device  110  at a different time point. 
     For example,  FIG. 7  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a fourth embodiment of the present disclosure. The method of  FIG. 7  is similar with the method of aforementioned  FIG. 6 , but in the embodiment of  FIG. 7 , the first member device  120  performs the operation  702  instead of the operation  602 . 
     In the operation  702 , the first control circuit  125  utilizes the first communication circuit  121  to transmit a device information of the first member device  120  to the Bluetooth host device  110 , but does not transmit the device information of other member devices (e.g., the second member device  130 ) to the Bluetooth host device  110 . For example, the first control circuit  125  may generate one or more target Bluetooth packets containing the device information of the first member device  120  but not containing the device information of the second member device  130 , and utilize the first communication circuit  121  to transmit the one or more target Bluetooth packets to the Bluetooth host device  110 . 
     The type of the target Bluetooth packets referred to in the operation  72  may be the same as the type of the target Bluetooth packets referred to in the aforementioned operation  202 . For the sake of brevity, the descriptions will not be repeated here. 
     In the operation  704 , the host-side communication circuit  111  of the Bluetooth host device  110  may receive the device information of the first member device  120  transmitted from the first member device  120 . 
     In the embodiment of  FIG. 7 , the first control circuit  125  performs the operation  708  to utilize the first communication circuit  121  to transmit the device information of the second member device  130  (e.g., a Bluetooth device address of the second member device  130 ) to the Bluetooth host device  110  after generating the second cypher key Key- 2 . 
     In this situation, the host-side communication circuit  111  may perform the operation  710  to receive the device information of the second member device  130  transmitted from the first member device  120 . 
     Then, the processing circuit  117  may perform the operation  614  of  FIG. 7  to create a correlation between the second member device  130  and the first cypher key Key- 1 . 
     The operations of the Bluetooth communication system  100  in others operations of  FIG. 7  are the same as in the corresponding operations of the aforementioned embodiment of  FIG. 6 . Accordingly, the aforementioned descriptions regarding corresponding operations in  FIG. 6  and related advantages are also applicable to the embodiment of  FIG. 7 . For the sake of brevity, the descriptions will not be repeated here. 
     According to the foregoing descriptions of  FIG. 6  and  FIG. 7 , it can be appreciated that only the Bluetooth host device  110  and the first member device  120  are required to respectively generate the corresponding first cypher key Key- 1  and second cypher key Key- 2  in this embodiment. Other member devices (e.g., the second member device  130  and the third member device  140 ) would directly use the second cypher key Key- 2  generated by the first member device  120  to conduct subsequent Bluetooth data transmissions with the Bluetooth host device  110 , without generating related cypher keys by themselves. Accordingly, by adopting the method of  FIG. 6  or  FIG. 7 , it can significantly reduce the time and computing loading of other member devices of the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ) required for negotiating the key parameters with the Bluetooth host device  110 , and also save their time and computing load required for generating the cypher keys. 
     Additionally, in the embodiments of  FIG. 6  and  FIG. 7 , the Bluetooth host device  110  only needs to negotiate the parameters of key generation with a single member device in the Bluetooth device set  102  (i.e., the first member device  120 ), and does not need to negotiate the parameters of key generation with other member devices of the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ). In other words, by adopting the method of  FIG. 6  or  FIG. 7 , it can also greatly reduce the time and computing loading of the Bluetooth host device  110  required for negotiating the key parameters with other member devices and required for generating cypher keys. 
     Apparently, the method of above  FIG. 6  and  FIG. 7  can effectively simplify the Bluetooth pairing procedure between the Bluetooth host device  110  and respective member device of the Bluetooth device set  102 , thereby significantly reduce the required time for completing the pairing procedure between the Bluetooth host device  110  and the Bluetooth device set  102 . 
     Furthermore, the operation of filtering device items to be shown in the candidate device list conducted by the processing circuit  117  in the aforementioned operation  606  can simplify the complexity of user&#39;s manipulation during the Bluetooth pairing procedure, and also reduce the possibility of user&#39;s erroneous manipulation. 
     Additionally, in the embodiments where the Bluetooth host device  110  and the member devices in the Bluetooth device set  102  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the member devices of the Bluetooth device set  102 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102  to thereby extend the serving time of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102 , but also effectively improves the overall quality of the audio playback operations. 
     Please refer to  FIG. 8 , which shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a fifth embodiment of the present disclosure. 
     As described previously, when the Bluetooth host device  110  wants to conduct pairing with respective member devices of the Bluetooth device set  102 , the processing circuit  117  may generate a Bluetooth inquiry request containing the device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ), and may utilize the host-side communication circuit  111  to transmit the Bluetooth inquiry request to other nearby Bluetooth devices. 
     Similarly, the processing circuit  117  may control the host-side communication circuit  111  to operate in the aforementioned predetermined receiving mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs. 
     On the other hand, all member devices in the Bluetooth device set  102  may enter a predetermined transmitting mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs, or may operate in the predetermined transmitting mode after receiving the Bluetooth inquiry request generated by the Bluetooth host device  110 . 
     The first member device  120  may perform the operation  602  of  FIG. 8  after entering the predetermined transmitting mode. The operations of the Bluetooth communication system  100  in the operation  602  through the operation  612  of  FIG. 8  are the same as in the corresponding operations of the aforementioned embodiment of  FIG. 6 . Accordingly, the foregoing descriptions regarding corresponding operations in  FIG. 6  and related advantages are also applicable to the embodiment of  FIG. 8 . For the sake of brevity, the descriptions will not be repeated here. 
     As shown in  FIG. 8 , after generating the second cypher key Key- 2  in the operation  610 , the first control circuit  125  of this embodiment may perform the operation  802 . 
     In the operation  802 , the first control circuit  125  may execute a predetermined cypher key algorithm to generate a third cypher key Key- 3  and a corresponding fourth cypher key Key- 4 . Then, the first control circuit  125  may perform the operation  802  and the operation  804 . 
     In the operation  804 , the first control circuit  125  may utilize the first communication circuit  121  to transmit the third cypher key Key- 3  to the Bluetooth host device  110 . 
     In the operation  806 , the first control circuit  125  may utilize the first communication circuit  121  to transmit a device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ) and the fourth cypher key Key- 4  to the second member device  130 . 
     In this situation, the Bluetooth host device  110  may perform the operation  808  and the operation  810 , and the second member device  130  may perform the operation  812 . 
     In the operation  808 , the host-side communication circuit  111  may receive the third cypher key Key- 3  transmitted from the first member device  120 . 
     In the operation  810 , the processing circuit  117  may create a correlation between the second member device  130  and the third cypher key Key- 3 . 
     In the operation  812 , the second communication circuit  131  of the second member device  130  may receive the fourth cypher key Key- 4  and the device information of the Bluetooth host device  110  transmitted from the first member device  120 . 
     Then, the processing circuit  117  may perform the operation  814  to establish a connection with the second member device  130  through the host-side communication circuit  111 , and directly use the third cypher key Key- 3  generated by the first member device  120  to conduct Bluetooth data transmissions with the second member device  130 . 
     The second control circuit  135  may perform the operation  816  to establish a connection with the Bluetooth host device  110  through the second communication circuit  131  according to the device information of the Bluetooth host device  110 , and directly use the fourth cypher key Key- 4  generated by the first member device  120  to conduct Bluetooth data transmissions with the Bluetooth host device  110 . 
     In practice, the first control circuit  125  may generate required key pairs for conducting subsequent Bluetooth data transmissions for the Bluetooth host device  110  and other member devices by adopting the same approach described above. 
     In the embodiments where the Bluetooth host device  110 , the first member device  120 , and the second member device  130  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the first member device  120  and the second member device  130 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110 , the first member device  120 , and the second member device  130  to thereby extend the serving time of the Bluetooth host device  110 , the first member device  120 , and the second member device  130 , but also effectively improves the overall quality of the audio playback operations. 
     In the above embodiment of  FIG. 8 , the first member device  120  transmits the device information of the first member device  120  and the device information of the second member device  130  to the Bluetooth host device  110  in the operation  602 . But this merely an exemplary embodiment, rather than a restriction to practical implementations. In practice, the first member device  120  may instead transmit the device information of the second member device  130  to the Bluetooth host device  110  at another different time point. 
     For example,  FIG. 9  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a sixth embodiment of the present disclosure. The method of  FIG. 9  is similar with the method of aforementioned  FIG. 8 , but in the embodiment of  FIG. 9 , the first member device  120  performs the operation  702  instead of the operation  602 . 
     As described previously, in the operation  702 , the first control circuit  125  utilizes the first communication circuit  121  to transmit a device information of the first member device  120  to the Bluetooth host device  110 , but does not transmit the device information of other member devices (e.g., the second member device  130 ) to the Bluetooth host device  110 . For example, the first control circuit  125  may generate one or more target Bluetooth packets containing the device information of the first member device  120  but not containing the device information of the second member device  130 , and utilize the first communication circuit  121  to transmit the one or more target Bluetooth packets to the Bluetooth host device  110 . 
     The type of the target Bluetooth packets referred to in the operation  72  may be the same as the type of the target Bluetooth packets referred to in the aforementioned operation  202 . For the sake of brevity, the descriptions will not be repeated here. 
     In the operation  704 , the host-side communication circuit  111  of the Bluetooth host device  110  may receive the device information of the first member device  120  transmitted from the first member device  120 . 
     In the embodiment of  FIG. 9 , the first control circuit  125  performs the operation  904  to utilize the first communication circuit  121  to transmit the device information of the second member device  130  (e.g., a Bluetooth device address of the second member device  130 ) and the third cypher key Key- 3  to the Bluetooth host device  110  after generating the second cypher key Key- 2  in the operation  612 . 
     In this situation, the host-side communication circuit  111  may perform the operation  908  to receive the device information of the second member device  130  and the third cypher key Key- 3  transmitted from the first member device  120 . 
     Then, the processing circuit  117  may perform the operation  810  of  FIG. 9  to create a correlation between the second member device  130  and the third cypher key Key- 3 . 
     Then, the processing circuit  117  may perform the operation  814  of  FIG. 9  to establish a connection with the second member device  130  through the host-side communication circuit  111 , and directly use the third cypher key Key- 3  generated by the first member device  120  to conduct Bluetooth data transmissions with the second member device  130 . 
     The second control circuit  135  may perform the operation  816  of  FIG. 9  to establish a connection with the Bluetooth host device  110  through the second communication circuit  131  according to the device information of the Bluetooth host device  110 , and directly use the fourth cypher key Key- 4  generated by the first member device  120  to conduct Bluetooth data transmissions with the Bluetooth host device  110 . 
     The operations of the Bluetooth communication system  100  in others operations of  FIG. 9  are the same as in the corresponding operations of the aforementioned embodiments of  FIG. 6 ,  FIG. 7 , or  FIG. 8 . Accordingly, the aforementioned descriptions regarding corresponding operations in  FIG. 6 ,  FIG. 7 ,  FIG. 8 , and related advantages are also applicable to the embodiment of  FIG. 9 . For the sake of brevity, the descriptions will not be repeated here. 
     According to the foregoing descriptions of  FIG. 8  and  FIG. 9 , it can be appreciated that only the Bluetooth host device  110  and the first member device  120  are required to respectively generate the corresponding first cypher key Key- 1  and second cypher key Key- 2  in this embodiment. However, the required cypher keys for conducting subsequent Bluetooth data transmissions between the Bluetooth host device  110  and other member devices in the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ) are generated by the first member device  120  alone. Accordingly, by adopting the method of  FIG. 8  or  FIG. 9 , it can significantly reduce the time and computing loading of other member devices of the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ) required for negotiating the key parameters with the Bluetooth host device  110 , and also save their time and computing load required for generating the cypher keys. 
     Additionally, in the embodiments of  FIG. 8  and  FIG. 9 , the Bluetooth host device  110  only needs to negotiate the parameters of key generation with a single member device in the Bluetooth device set  102  (i.e., the first member device  120 ), and does not need to negotiate the parameters of key generation with other member devices of the Bluetooth device set  102  (e.g., the second member device  130  and the third member device  140 ). In other words, by adopting the method of  FIG. 8  or  FIG. 9 , it can also greatly reduce the time and computing loading of the Bluetooth host device  110  required for negotiating the key parameters with other member devices and required for generating cypher keys. 
     Apparently, the method of above  FIG. 8  and  FIG. 9  can effectively simplify the Bluetooth pairing procedure between the Bluetooth host device  110  and respective member device of the Bluetooth device set  102 , thereby significantly reduce the required time for completing the pairing procedure between the Bluetooth host device  110  and the Bluetooth device set  102 . 
     Furthermore, the operation of filtering device items to be shown in the candidate device list conducted by the processing circuit  117  in the aforementioned operation  606  can simplify the complexity of user&#39;s manipulation during the Bluetooth pairing procedure, and also reduce the possibility of user&#39;s erroneous manipulation. 
     Additionally, in the embodiments where the Bluetooth host device  110  and the member devices in the Bluetooth device set  102  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the member devices of the Bluetooth device set  102 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102  to thereby extend the serving time of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102 , but also effectively improves the overall quality of the audio playback operations. 
     Please refer to  FIG. 10 , which shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a seventh embodiment of the present disclosure. 
     As described previously, when the Bluetooth host device  110  wants to conduct pairing with respective member devices of the Bluetooth device set  102 , the processing circuit  117  may generate a Bluetooth inquiry request containing the device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ), and may utilize the host-side communication circuit  111  to transmit the Bluetooth inquiry request to other nearby Bluetooth devices. 
     Similarly, the processing circuit  117  may control the host-side communication circuit  111  to operate in the aforementioned predetermined receiving mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs. 
     On the other hand, all member devices in the Bluetooth device set  102  may enter a predetermined transmitting mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs, or may operate in the predetermined transmitting mode after receiving the Bluetooth inquiry request generated by the Bluetooth host device  110 . 
     The first member device  120  may perform the operation  602  of  FIG. 10  after entering the predetermined transmitting mode. The operations of the Bluetooth communication system  100  in the operation  602  through the operation  608  of  FIG. 10  are the same as in the corresponding operations of the aforementioned embodiment of  FIG. 6 . Accordingly, the foregoing descriptions regarding corresponding operations in  FIG. 6  and related advantages are also applicable to the embodiment of  FIG. 10 . For the sake of brevity, the descriptions will not be repeated here. 
     As shown in  FIG. 10 , the Bluetooth host device  110  of this embodiment may perform the operation  1010  after receiving a selection command issued by the user in the operation  608 . 
     In the operation  1010 , the processing circuit  117  may establish a connection with the first member device  120  through the host-side communication circuit  111  according to the selection command, and transmit a device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ) to the first member device  120 . 
     In this situation, the first communication circuit  121  may perform the operation  1012  to receive the device information of the Bluetooth host device  110 , and may establish a connection with the Bluetooth host device  110  under control of the first control circuit  125 . In addition, the first control circuit  125  further generate an indication value required for conducting the Bluetooth pairing between the Bluetooth host device  110  and the first member device  120  in the operation  1012 . 
     In one embodiment, the aforementioned indication value is a predetermined value, a random value, a predetermined address, a random address, a predetermined string, a random string, a predetermined token, a random token, or the like for use in a predetermined cypher key algorithm. In another embodiment, the aforementioned indication value is an algorithm identifier corresponding to a predetermined cypher key algorithm. 
     After generating the indication value, the first member device  120  may perform the operation  1014 , the operation  1016 , and the operation  1018 . 
     In the operation  1014 , the first control circuit  125  may generate a second cypher key Key- 2  according to the indication value and a device information of the first member device  120  (e.g., a Bluetooth device address of the first member device  120 ). For example, the first control circuit  125  may execute the aforementioned predetermined cypher key algorithm to generate the second cypher key Key- 2  according to the indication value and the device information of the first member device  120 . For another example, the first control circuit  125  may execute the aforementioned predetermined cypher key algorithm to generate the second cypher key Key- 2  according to the indication value, the device information of the first member device  120 , and the device information of the Bluetooth host device  110 . For another example, the first control circuit  125  may select a predetermined cypher key algorithm from a plurality of pre-agreed key algorithms according to the indication value, and execute the selected predetermined cypher key algorithm to generate the second cypher key Key- 2 . 
     In the operation  1016 , the first control circuit  125  may utilize the first communication circuit  121  to transmit the indication value to the Bluetooth host device  110 . 
     In the operation  1018 , the first control circuit  125  may utilize the first communication circuit  121  to transmit the device information of the Bluetooth host device  110  and the indication value to the second member device  130 . 
     In this situation, the Bluetooth host device  110  may perform the operation  1020  and the operation  1022  of  FIG. 10 , and the second member device  130  may perform the operation  1024  of  FIG. 10 . 
     In the operation  1020 , the host-side communication circuit  111  may receive the indication value. 
     In the operation  1022 , the processing circuit  117  may generate a first cypher key Key- 1  according to the indication value and the device information of the first member device  120 . For example, the processing circuit  117  may execute the aforementioned predetermined cypher key algorithm to generate the first cypher key Key- 1  according to the indication value and the device information of the first member device  120 . For another example, the processing circuit  117  may execute the aforementioned predetermined cypher key algorithm to generate the first cypher key Key- 1  according to the indication value, the device information of the first member device  120 , and the device information of the Bluetooth host device  110 . For another example, the processing circuit  117  may select a predetermined cypher key algorithm from a plurality of pre-agreed key algorithms according to the indication value, and execute the selected predetermined cypher key algorithm to generate the first cypher key Key- 1 . 
     In the operation  1024 , the second communication circuit  131  may receive the device information of the Bluetooth host device  110  and the indication value transmitted from the first member device  120 . 
     In the operation  1026 , the processing circuit  117  may establish a connection with the second member device  130  through the host-side communication circuit  111  according to a device information of the second member device  130  (e.g., a Bluetooth device address of the second member device  130 ) transmitted from the first member device  120  in the operation  602 , and generate a third cypher key Key- 3  according to the indication value and the device information of the second member device  130 . For example, the processing circuit  117  may execute the aforementioned predetermined cypher key algorithm to generate the third cypher key Key- 3  according to the indication value and the device information of the second member device  130 . For another example, the processing circuit  117  may execute the aforementioned predetermined cypher key algorithm to generate the third cypher key Key- 3  according to the indication value, the second member device  130 , and the device information of the Bluetooth host device  110 . For another example, the processing circuit  117  may select a predetermined cypher key algorithm from a plurality of pre-agreed key algorithms according to the indication value, and execute the selected predetermined cypher key algorithm to generate the third cypher key Key- 3 . 
     In this situation, the second member device  130  may perform the operation  1028 . 
     In the operation  1028 , the second control circuit  135  may establish a connection with the Bluetooth host device  110  through the second communication circuit  131 , and generate a fourth cypher key Key- 4  corresponding to the third cypher key Key- 3  according to the indication value and the device information of the second member device  130 . For example, the second control circuit  135  may execute the aforementioned predetermined cypher key algorithm to generate the fourth cypher key Key- 4  according to the indication value and the device information of the second member device  130 . For another example, the second control circuit  135  may execute the aforementioned predetermined cypher key algorithm to generate the fourth cypher key Key- 4  according to the indication value, the device information of the second member device  130 , and the device information of the Bluetooth host device  110 . For another example, the second control circuit  135  may select a predetermined cypher key algorithm from a plurality of pre-agreed key algorithms according to the indication value, and execute the selected predetermined cypher key algorithm to generate the fourth cypher key Key- 4 . 
     In other words, after the indication value is generated by the first member device  120 , the Bluetooth host device  110  and the first member device  120  may omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding first cypher key Key- 1  and second cypher key Key- 2 . Similarly, the Bluetooth host device  110  and the second member device  130  may also omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding third cypher key Key- 3  and fourth cypher key Key- 4 . As a result, it can significantly reduce the required time for generating the first cypher key Key- 1 , the second cypher key Key- 2 , the third cypher key Key- 3 , and the fourth cypher key Key- 4 . 
     In the operation  1030 , the processing circuit  117  of the Bluetooth host device  110  may use the third cypher key Key- 3  to conduct Bluetooth data transmissions with the second member device  130  through the host-side communication circuit  111 . 
     In the operation  1032 , the second control circuit  135  of the second member device  130  may use the fourth cypher key Key- 4  to conduct Bluetooth data transmissions with the Bluetooth host device  110  through the second communication circuit  131 . 
     In practice, the Bluetooth host device  110  and other member devices in the Bluetooth device set  102  (e.g., the third member device  140 ) may adopt the aforementioned approach to respectively generate the cypher keys required for conducting subsequent Bluetooth data transmission according to the indication value generated by the first member device  120 . 
     Similarly, in the embodiments where the Bluetooth host device  110 , the first member device  120 , and the second member device  130  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the first member device  120  and the second member device  130 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110 , the first member device  120 , and the second member device  130  to thereby extend the serving time of the Bluetooth host device  110 , the first member device  120 , and the second member device  130 , but also effectively improves the overall quality of the audio playback operations. 
     In the above embodiment of  FIG. 10 , the first member device  120  transmits the device information of the first member device  120  and the device information of the second member device  130  to the Bluetooth host device  110  in the operation  602 . But this merely an exemplary embodiment, rather than a restriction to practical implementations. In practice, the first member device  120  may instead transmit the device information of the second member device  130  to the Bluetooth host device  110  at another different time point. 
     For example,  FIG. 11  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to an eighth embodiment of the present disclosure. The method of  FIG. 11  is similar with the method of aforementioned  FIG. 10 , but in the embodiment of  FIG. 11 , the first member device  120  performs the operation  702  instead of the operation  602 . 
     As described previously, in the operation  702 , the first control circuit  125  utilizes the first communication circuit  121  to transmit a device information of the first member device  120  to the Bluetooth host device  110 , but does not transmit the device information of other member devices (e.g., the second member device  130 ) to the Bluetooth host device  110 . For example, the first control circuit  125  may generate one or more target Bluetooth packets containing the device information of the first member device  120  but not containing the device information of the second member device  130 , and utilize the first communication circuit  121  to transmit the one or more target Bluetooth packets to the Bluetooth host device  110 . 
     The type of the target Bluetooth packets referred to in the operation  72  may be the same as the type of the target Bluetooth packets referred to in the aforementioned operation  202 . For the sake of brevity, the descriptions will not be repeated here. 
     In the operation  704 , the host-side communication circuit  111  of the Bluetooth host device  110  may receive the device information of the first member device  120  transmitted from the first member device  120 . 
     In the embodiment of  FIG. 11 , the first control circuit  125  performs the operation  1118  to utilize the first communication circuit  121  to transmit the device information of the second member device  130  (e.g., a Bluetooth device address of the second member device  130 ) to the Bluetooth host device  110  after generating the second cypher key Key- 2  in the operation  1014 . 
     In this situation, the host-side communication circuit  111  may perform the operation  1120  to receive the device information of the second member device  130  transmitted from the first member device  120 . 
     The operations of the Bluetooth communication system  100  in others operations of  FIG. 11  are the same as in the corresponding operations of the aforementioned embodiments of  FIG. 6 ,  FIG. 7 , or  FIG. 8 . Accordingly, the aforementioned descriptions regarding corresponding operations in  FIG. 6 ,  FIG. 7 ,  FIG. 8 , and related advantages are also applicable to the embodiment of  FIG. 9 . For the sake of brevity, the descriptions will not be repeated here. 
     According to the foregoing descriptions of  FIG. 6  and  FIG. 7 , it can be appreciated that after the aforementioned indication value is generated by the first member device  120 , the Bluetooth host device  110  and the first member device  120  may omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding first cypher key Key- 1  and second cypher key Key- 2 . That is, the Bluetooth host device  110  is enabled to generate the first cypher key Key- 1  by simply performing the aforementioned operation  1020  and operation  1022  while the first member device  120  is enabled to generate the second cypher key Key- 2  by simply performing the aforementioned operation  1014 . As a result, it can significantly reduce the required time for generating the first cypher key Key- 1  and the second cypher key Key- 2 . 
     Similarly, the Bluetooth host device  110  and the second member device  130  can also omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding third cypher key Key- 3  and fourth cypher key Key- 4 . That is, the Bluetooth host device  110  is enabled to generate the third cypher key Key- 3  by simply performing the aforementioned operation  1026  while the second member device  130  is enabled to generate the fourth cypher key Key- 4  by simply performing the aforementioned operation  1028 . As a result, it can significantly reduce the required time for generating the third cypher key Key- 3  and the fourth cypher key Key- 4 . 
     Apparently, the method of above  FIG. 10  and  FIG. 11  can effectively simplify the Bluetooth pairing procedure between the Bluetooth host device  110  and respective member device of the Bluetooth device set  102 , thereby significantly reduce the required time for completing the pairing procedure between the Bluetooth host device  110  and the Bluetooth device set  102 . 
     Furthermore, the operation of filtering device items to be shown in the candidate device list conducted by the processing circuit  117  in the aforementioned operation  606  can simplify the complexity of user&#39;s manipulation during the Bluetooth pairing procedure, and also reduce the possibility of user&#39;s erroneous manipulation. 
     Additionally, in the embodiments where the Bluetooth host device  110  and the member devices in the Bluetooth device set  102  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the member devices of the Bluetooth device set  102 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102  to thereby extend the serving time of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102 , but also effectively improves the overall quality of the audio playback operations. 
     Please refer to  FIG. 12 , which shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a ninth embodiment of the present disclosure. 
     As described previously, when the Bluetooth host device  110  wants to conduct pairing with respective member devices of the Bluetooth device set  102 , the processing circuit  117  may generate a Bluetooth inquiry request containing the device information of the Bluetooth host device  110  (e.g., a Bluetooth device address of the Bluetooth host device  110 ), and may utilize the host-side communication circuit  111  to transmit the Bluetooth inquiry request to other nearby Bluetooth devices. 
     Similarly, the processing circuit  117  may control the host-side communication circuit  111  to operate in the aforementioned predetermined receiving mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs. 
     On the other hand, all member devices in the Bluetooth device set  102  may enter a predetermined transmitting mode at an appropriate time according to the user&#39;s manipulation, or based on the default operating instructions of the internal programs, or may operate in the predetermined transmitting mode after receiving the Bluetooth inquiry request generated by the Bluetooth host device  110 . 
     The first member device  120  may perform the operation  602  of  FIG. 12  after entering the predetermined transmitting mode. The operations of the Bluetooth communication system  100  in the operation  602  through the operation  608  of  FIG. 12  are the same as in the corresponding operations of the aforementioned embodiment of  FIG. 6 . Accordingly, the foregoing descriptions regarding corresponding operations in  FIG. 6  and related advantages are also applicable to the embodiment of  FIG. 12 . For the sake of brevity, the descriptions will not be repeated here. 
     As shown in  FIG. 12 , the Bluetooth host device  110  of this embodiment may perform the operation  1210  after receiving a selection command issued by the user in the operation  608 . 
     In the operation  1210 , the processing circuit  117  may establish a connection with the first member device  120  through the host-side communication circuit  111  according to the selection command, and may decide a first parameter P 1 . The processing circuit  117  may adopt the same approach as employed in the aforementioned operation  210  to decide the first parameter P 1 . Accordingly, the foregoing descriptions regarding how to decide the first parameter P 1  in the operation  210  are also applicable to the operation  1210 , and will not be repeated here for the sake of brevity. The processing circuit  117  may also transmit the first parameter P 1  or a first field indication to the first member device  120  through the host-side communication circuit  111  in the operation  1210 , wherein the first field indication is utilized for indicating a specific packet field whose content is to be utilized as the first parameter P 1 . 
     In this situation, the first communication circuit  121  of the first member device  120  may perform the operation  1212  to establish a connection with the Bluetooth host device  110 , and to receive the first parameter P 1  or a related first field indication transmitted from the Bluetooth host device  110 , so that the first control circuit  125  is enabled to learn the first parameter P 1  decided by the Bluetooth host device  110  accordingly. 
     As shown in  FIG. 12 , the processing circuit  117  then may perform the operation  214  to generate a first cypher key Key- 1  required for conducting subsequent Bluetooth data transmissions with the first member device  120  according to the first parameter P 1 . For example, the processing circuit  117  may execute a predetermined cypher key algorithm to generate the first cypher key Key- 1  according to the first parameter P 1  and the device information of the Bluetooth host device  110 . For another example, the processing circuit  117  may execute the aforementioned predetermined cypher key algorithm to generate the first cypher key Key- 1  according to the first parameter P 1 , the device information of the Bluetooth host device  110 , and the device information of the first member device  120 . 
     On the other hand, the first control circuit  125  may perform the operation  216  to generate a second cypher key Key- 2  required for conducting subsequent Bluetooth data transmissions with the Bluetooth host device  110  according to the first parameter P 1 . In other words, the second cypher key Key- 2  generated by the first control circuit  125  and the first cypher key Key- 1  generated by the processing circuit  117  will correspond to each other. For example, the first control circuit  125  may execute the aforementioned predetermined cypher key algorithm to generate the second cypher key Key- 2  according to the first parameter P 1  and the device information of the first member device  120 . For another example, the first control circuit  125  may execute the aforementioned predetermined cypher key algorithm to generate the second cypher key Key- 2  according to the first parameter P 1 , the device information of the first member device  120 , and the device information of the Bluetooth host device  110 . 
     In other words, after the first parameter P 1  is decided by the Bluetooth host device  110 , the Bluetooth host device  110  and the first member device  120  can omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding first cypher key Key- 1  and second cypher key Key- 2 . That is, the Bluetooth host device  110  can directly generate the first cypher key Key- 1  based on the first parameter P 1  decided by the Bluetooth host device  110 , and the first member device  120  can directly generate the second cypher key Key- 2  based on the first parameter P 1  decided by the Bluetooth host device  110 . As a result, it can significantly reduce the required time for generating the first cypher key Key- 1  and the second cypher key Key- 2 . 
     Afterwards, the processing circuit  117  may use the first cypher key Key- 1  to conduct Bluetooth data transmissions with the first member device  120  through the host-side communication circuit  111 , and the first control circuit  125  may use the second cypher key Key- 2  to conduct Bluetooth data transmissions with the Bluetooth host device  110  through the first communication circuit  121 . 
     As shown in  FIG. 12 , the first control circuit  125  may further perform the operation  1216  to utilize the first communication circuit  121  to transmit the device information of the Bluetooth host device  110  to the second member device  130 . 
     In this situation, the second communication circuit  131  may perform the operation  1218  of  FIG. 12  to receive the device information of the Bluetooth host device  110  transmitted from the first member device  120 . 
     As shown in  FIG. 12 , the Bluetooth host device  110  of this embodiment may further perform the operation  1220 . 
     In the operation  1220 , the processing circuit  117  may establish a connection with the second member device  130  through the host-side communication circuit  111  according to a device information of the second member device  130  (e.g., a Bluetooth device address of the second member device  130 ) transmitted from the first member device  120  in the operation  602 , and may decide a second parameter P 2 . The processing circuit  117  may adopt the same approach as employed in the aforementioned operation  314  to decide the second parameter P 2 . Accordingly, the foregoing descriptions regarding how to decide the second parameter P 2  in the operation  314  are also applicable to the operation  1220 , and will not be repeated here for the sake of brevity. The processing circuit  117  may also transmit the second parameter P 2  or a second field indication to the first member device  120  through the host-side communication circuit  111  in the operation  1220 , wherein the second field indication is utilized for indicating a specific packet field whose content is to be utilized as the second parameter P 2 . 
     In this situation, the first communication circuit  121  of the first member device  120  may perform the operation  1222  to establish a connection with the Bluetooth host device  110 , and to receive the second parameter P 2  or a related second field indication transmitted from the Bluetooth host device  110 , so that the first control circuit  125  is enabled to learn the second parameter P 2  decided by the Bluetooth host device  110  accordingly. 
     As shown in  FIG. 12 , the processing circuit  117  then may perform the operation  318  to generate a third cypher key Key- 3  required for conducting subsequent Bluetooth data transmissions with the second member device  130  according to the second parameter P 2 . For example, the processing circuit  117  may execute a predetermined cypher key algorithm according to the second parameter P 2  and the device information of the Bluetooth host device  110  to generate the third cypher key Key- 3 . For another example, the processing circuit  117  may execute the aforementioned predetermined cypher key algorithm according to the second parameter P 2 , the device information of the second member device  130 , and the device information of the Bluetooth host device  110  to generate the third cypher key Key- 3 . 
     On the other hand, the second control circuit  135  may perform the operation  320  to generate a fourth cypher key Key- 4  required for conducting subsequent Bluetooth data transmissions with the Bluetooth host device  110  according to the second parameter P 2 . In other words, the fourth cypher key Key- 4  generated by the second control circuit  135  and the third cypher key Key- 3  generated by the processing circuit  117  will correspond to each other. For example, the second control circuit  135  may generate the aforementioned predetermined cypher key algorithm according to the second parameter P 2  and the device information of the second member device  130  to generate the fourth cypher key Key- 4 . For another example, the second control circuit  135  may execute the aforementioned predetermined cypher key algorithm according to the second parameter P 2 , the device information of the second member device  130 , and the device information of the Bluetooth host device  110  to generate the fourth cypher key Key- 4 . 
     In other words, after the second parameter P 2  is decided by the Bluetooth host device  110 , the Bluetooth host device  110  and the second member device  130  may omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding third cypher key Key- 3  and fourth cypher key Key- 4 . That is, the Bluetooth host device  110  can directly generate the third cypher key Key- 3  based on the second parameter P 2  decided by the Bluetooth host device  110  while the second member device  130  can directly generate the fourth cypher key Key- 4  based on the second parameter P 2  decided by the Bluetooth host device  110 . As a result, it can significantly reduce the required time for generating the third cypher key Key- 3  and the fourth cypher key Key- 4 . 
     Afterwards, the processing circuit  117  may perform the operation  322  of  FIG. 12  to use the third cypher key Key- 3  to conduct Bluetooth data transmissions with the second member device  130  through the host-side communication circuit  111 . 
     On the other hand, the second control circuit  135  may perform the operation  324  of  FIG. 12  to use the fourth cypher key Key- 4  to conduct Bluetooth data transmissions with the Bluetooth host device  110  through the second communication circuit  131 . 
     Similarly, in the embodiments where the Bluetooth host device  110 , the first member device  120 , and the second member device  130  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the first member device  120  and the second member device  130 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110 , the first member device  120 , and the second member device  130  to thereby extend the serving time of the Bluetooth host device  110 , the first member device  120 , and the second member device  130 , but also effectively improves the overall quality of the audio playback operations. 
     In the above embodiment of  FIG. 12 , the first member device  120  transmits the device information of the first member device  120  and the device information of the second member device  130  to the Bluetooth host device  110  in the operation  602 . But this merely an exemplary embodiment, rather than a restriction to practical implementations. In practice, the first member device  120  may instead transmit the device information of the second member device  130  to the Bluetooth host device  110  at another different time point. 
     For example,  FIG. 13  shows a simplified flowchart of a method for generating cypher keys required for Bluetooth data transmission according to a tenth embodiment of the present disclosure. The method of  FIG. 13  is similar with the method of aforementioned  FIG. 12 , but in the embodiment of  FIG. 13 , the first member device  120  performs the operation  702  instead of the operation  602 . 
     As described previously, in the operation  702 , the first control circuit  125  utilizes the first communication circuit  121  to transmit a device information of the first member device  120  to the Bluetooth host device  110 , but does not transmit the device information of other member devices (e.g., the second member device  130 ) to the Bluetooth host device  110 . For example, the first control circuit  125  may generate one or more target Bluetooth packets containing the device information of the first member device  120  but not containing the device information of the second member device  130 , and utilize the first communication circuit  121  to transmit the one or more target Bluetooth packets to the Bluetooth host device  110 . 
     The type of the target Bluetooth packets referred to in the operation  72  may be the same as the type of the target Bluetooth packets referred to in the aforementioned operation  202 . For the sake of brevity, the descriptions will not be repeated here. 
     In the operation  704 , the host-side communication circuit  111  of the Bluetooth host device  110  may receive the device information of the first member device  120  transmitted from the first member device  120 . 
     In the embodiment of  FIG. 11 , the first control circuit  125  performs the operation  1118  to utilize the first communication circuit  121  to transmit the device information of the second member device  130  (e.g., a Bluetooth device address of the second member device  130 ) to the Bluetooth host device  110  after generating the second cypher key Key- 2  in the operation  216 . 
     In this situation, the host-side communication circuit  111  may perform the operation  1120  to receive the device information of the second member device  130  transmitted from the first member device  120 . 
     The operations of the Bluetooth communication system  100  in others operations of  FIG. 13  are the same as in the corresponding operations of the aforementioned embodiments of  FIG. 2 ,  FIG. 3 ,  FIG. 6 ,  FIG. 7 , or  FIG. 23 . Accordingly, the aforementioned descriptions regarding corresponding operations in  FIG. 2 ,  FIG. 3 ,  FIG. 6 ,  FIG. 7 ,  FIG. 23 , and related advantages are also applicable to the embodiment of  FIG. 13 . For the sake of brevity, the descriptions will not be repeated here. 
     According to the foregoing descriptions of  FIG. 12  and  FIG. 13 , it can be appreciated that after the first parameter P 1  is decided by the Bluetooth host device  110 , the Bluetooth host device  110  and the first member device  120  can omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding first cypher key Key- 1  and second cypher key Key- 2 . As a result, it can significantly reduce the required time for generating the first cypher key Key- 1  and the second cypher key Key- 2 . 
     Similarly, after the first parameter P 1  is decided by the Bluetooth host device  110 , the Bluetooth host device  110  and the second member device  130  can also omit many traditional key parameter negotiation steps, and instead adopt a highly simplified approach to generate the corresponding third cypher key Key- 3  and fourth cypher key Key- 4 . As a result, it can significantly reduce the required time for generating the third cypher key Key- 3  and the fourth cypher key Key- 4 . 
     Apparently, the method of above  FIG. 12  and  FIG. 13  can effectively simplify the Bluetooth pairing procedure between the Bluetooth host device  110  and respective member device of the Bluetooth device set  102 , thereby significantly reduce the required time for completing the pairing procedure between the Bluetooth host device  110  and the Bluetooth device set  102 . 
     Furthermore, the operation of filtering device items to be shown in the candidate device list conducted by the processing circuit  117  in the aforementioned operation  606  can simplify the complexity of user&#39;s manipulation during the Bluetooth pairing procedure, and also reduce the possibility of user&#39;s erroneous manipulation. 
     Additionally, in the embodiments where the Bluetooth host device  110  and the member devices in the Bluetooth device set  102  support the BLE Audio technology, the Bluetooth host device  110  may adopt the BLE Audio technology to transmit audio data to the member devices of the Bluetooth device set  102 , and the Bluetooth host device  110  can utilize the Low Complexity Communication Codec (LC3) to encode the audio data. As a result, it not only reduces the power consumption of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102  to thereby extend the serving time of the Bluetooth host device  110  and the member devices of the Bluetooth device set  102 , but also effectively improves the overall quality of the audio playback operations. 
     Please note that the aforementioned executing order of the operations in each flowchart is merely an exemplary embodiment, rather than a restriction to the practical implementations of the present disclosure. 
     For example, in  FIG. 2 , the operation  214  may be performed at the same time with the operation  210 , or may be performed before transmitting the first privileged pairing notice, the first parameter P 1 , and/or a first field indication related to the first parameter P 1 . 
     For another example, in  FIG. 3  and  FIG. 5 , the operation  306  and the operation  308  may be performed before the operation  302 , or may be performed at the same time with the operation  302 . 
     For another example, in  FIG. 3  and  FIG. 5 , the operation  310  and the operation  304  may be performed in a reverse order, or may be performed at the same time. 
     For another example, in  FIG. 3  and  FIG. 5 , the operation  318  may be performed at the same time with the operation  314 , or may be performed before transmitting the second privileged pairing notice, the second parameter P 2 , and/or a second field indication related to the second parameter P 2 . 
     For another example, in  FIG. 4 , the operation  408  may be performed at the same time with the operation  410  or the operation  412 , or may be performed between the operation  410  and the operation  412 , or may be performed between the operation  412  and the operation  210 . 
     For another example, in  FIG. 7 , the operation  708  and the operation  616  may be performed in a reverse order, or may be performed at the same time. 
     For another example, in  FIG. 8 , the operation  806  and the operation  804  may be performed in a reverse order, or may be performed at the same time. 
     For another example, in  FIG. 9 , the operation  806  and the operation  904  may be performed in a reverse order, or may be performed at the same time. 
     For another example, in  FIG. 10  and  FIG. 11 , the operation  1018  and the operation  1016  may be performed in a reverse order, or may be performed at the same time. 
     For another example, in  FIG. 11 , the operation  1118  may be performed at the same time with the operation  1016  or the operation  1018 , or may be performed between the operation  1016  and the operation  1018 , or may be performed between the operation  1014  and the operation  1016 . 
     For another example, in  FIG. 12  and  FIG. 13 , the operation  1216  and the operation  216  may be performed in a reverse order, or may be performed at the same time. 
     For another example, in  FIG. 12  and  FIG. 13 , the operation  214  may be performed at the same time with the operation  1210 , or may be performed before transmitting the first parameter P 1  or a first field indication related to the first parameter P 1 . 
     For another example, in  FIG. 13 , the operation  1118  and the operation  1216  may be performed in a reverse order, or may be performed at the same time. 
     For another example, in  FIG. 12  and  FIG. 13 , the operation  318  may be performed at the same time with the operation  1220 , or may be performed before transmitting the second parameter P 2  or a second field indication related to the second parameter P 2 . 
     In addition, the quantity of functional blocks in the Bluetooth communication system  100  and the connection among the functional blocks may be modified based on the actual circuit design requirement, and are restricted to the case illustrated in the aforementioned embodiment. 
     For another example, in some embodiments where the Bluetooth device set  102  does not need to receive the user&#39;s voice or ambient sounds, the first voice receiving circuit  164 , the second voice receiving circuit  174 , and/or the third voice receiving circuit  184  may be omitted. 
     For another example, in some embodiments where the Bluetooth device set  102  does not need to playback audio data, the first audio playback circuit  162 , the second audio playback circuit  172 , and/or the third audio playback circuit  182  may be omitted. 
     For another example, the number of member devices in the Bluetooth device set  102  may be expanded to a larger number, or the Bluetooth device set  102  may be simplified to contain only the first member device  120  and the second member device  130 . 
     Certain terms are used throughout the description and the claims to refer to particular components. One skilled in the art appreciates that a component may be referred to as different names. This disclosure does not intend to distinguish between components that differ in name but not in function. In the description and in the claims, the term “comprise” is used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to.” The term “couple” is intended to encompass any indirect or direct connection. Accordingly, if this disclosure mentioned that a first device is coupled with a second device, it means that the first device may be directly or indirectly connected to the second device through electrical connections, wireless communications, optical communications, or other signal connections with/without other intermediate devices or connection means. 
     The term “and/or” may comprise any and all combinations of one or more of the associated listed items. In addition, the singular forms “a,” “an,” and “the” herein are intended to comprise the plural forms as well, unless the context clearly indicates otherwise. 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention indicated by the following claims.