JP2007067867A - Wireless communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication method for achieving simultaneous distribution on the basis of a simple and inexpensive communication configuration with a wireless communication system based on the Bluetooth standards. <P>SOLUTION: The wireless communication method has a step for setting a base time as an information generation source with master equipment in a high-order piconet, a step for executing connection processing by a Bluetooth core in the high-order piconet, a step for receiving the base time with slave equipment in the high-order piconet, a step for receiving a broadcast packet with the slave equipment in the high-order piconet, a step for switching a connection relationship when the slave equipment of the high-order piconet is master equipment of a low-order piconet, a step for executing the connection processing by the Bluetooth core in the low-order piconet, a step for transmitting the base time with the master equipment in the low-order piconet, and a step for transmitting the broadcast packet to the slave equipment with the master equipment in the low-order piconet. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication method, and more particularly to a wireless communication method capable of realizing a one-to-many broadcast communication method between multistage piconets between communication devices compliant with the Bluetooth (Bluetooth) standard.

  In recent years, the development of a wireless communication system employing the Bluetooth (registered trademark) standard for transmitting and receiving data between a plurality of communication devices using a 2.4 GHz frequency hopping system as a relatively narrow wireless communication system. Has been done. In this wireless communication system, a Bluetooth standard wireless module is installed in an electronic device such as a mobile phone, a portable information terminal, or a personal computer, and data is transmitted and received between these electronic devices. Hereinafter, an electronic device equipped with such a wireless module of the Bluetooth standard is referred to as a “Bluetooth device” or a “Bluetooth terminal”.

  According to the wireless communication system based on the Bluetooth standard, a communication network called “piconet” composed of a plurality of Bluetooth devices is defined. One piconet is composed of one master device and up to seven slave devices. The master device and the slave device are Bluetooth devices. More than 8 Bluetooth devices are assigned to belong to other piconets. Even the same Bluetooth device can belong to a plurality of different piconets. Bluetooth devices belonging to a plurality of piconets can communicate with each of the plurality of piconets. A group of piconets connected to each other via a single Bluetooth device is called a scatter net.

  As a prior art, an information collection system using a Bluetooth terminal has been proposed (Patent Document 1). The information collecting system (10) includes a communication unit (11), and a piconet (28) is formed between the communication unit (11) and each terminal (20, 21,...) Of a plurality of users. . The information collector performs communication with each terminal via the piconet by the communication means to collect information, and receives data including predetermined information unilaterally transmitted from each terminal by the receiving means (12). . Information can be easily collected from multiple terminals using Bluetooth terminals.

As a further prior art, a wireless communication device composed of communication devices based on the Bluetooth standard has been proposed (Patent Document 2). In this wireless communication apparatus, a slave device (3) belonging to two piconets includes a transmission control unit and an attribute change unit that changes an attribute parameter of a communication link with the master device (11, 21). Based on this configuration, when data is transmitted from a certain piconet to another piconet, a sufficient connectable time to the data transfer destination piconet can be secured, and communication across a plurality of piconets can be stably performed. .
JP 2002-368758 A JP 2005-64937 A

  In the wireless communication method based on the Bluetooth standard described above, since a Bluetooth device (node) belonging to one piconet needs to always be synchronized with a communication partner, each node cannot belong to two piconets at the same time. Receive. For this reason, according to the wireless communication system based on the Bluetooth standard, a one-to-one communication relationship must be created when performing communication. In other words, the wireless communication system based on the current Bluetooth standard has a problem that communication in a one-to-many relationship cannot be performed and it is not suitable for multi-node simultaneous distribution.

  The same applies to the wireless communication apparatus based on the Bluetooth standard according to Patent Documents 1 and 2 described above.

  In view of the above-mentioned problems, the object of the present invention is to enable simultaneous distribution based on a simple and inexpensive communication configuration in a wireless communication system based on the Bluetooth standard, and further, a one-to-many broadcast communication system between Bluetooth devices. An object of the present invention is to provide a wireless communication method that can be realized between multistage piconets.

  In order to achieve the above object, a wireless communication method according to the present invention is configured as follows.

  In the first wireless communication method (corresponding to claim 1), a piconet is formed by a plurality of Bluetooth devices connected so as to perform wireless communication according to the Bluetooth standard, and the plurality of Bluetooth devices in this piconet is one master device. And other slave devices, and one Bluetooth device belonging to one piconet as a slave device can be connected to belong to another piconet as a master device, and further, wireless communication of Bluetooth devices belonging to two piconets This is a wireless communication method that enables connection by wireless communication between two piconets based on the function. The wireless communication method includes a step in which a master device of an upper piconet sets a base time as an information generation source, a step of performing connection processing between the master device and each slave device in the upper piconet by a Bluetooth core, and a slave in the upper piconet The device receives the base time from the master device, the slave device in the higher-level piconet receives the broadcast packet from the master device, and the step of switching the connection relationship when the slave device in the higher-level piconet is the master device in the lower-level piconet And a step of performing connection processing between the master device and each slave device in the lower piconet by the Bluetooth core, a step in which the master device transmits base time to the slave device in the lower piconet, and the master device in the lower piconet is the slave device. And transmitting the broadcast packet, and a.

  According to the above wireless communication method, since the connection is performed based on the base time, reconnection may not be possible within the time of the base time. However, real-time performance can be maintained and effective for real-time audio distribution, etc. It is.

  The second wireless communication method (corresponding to claim 2) is the first method described above. Preferably, the base time transmission from the master device to the slave device in each of the upper piconet and the lower piconet is performed for the first time. It is characterized in that it is performed only once immediately before transmission of a broadcast packet.

  In the third wireless communication method (corresponding to claim 3), similarly to the first wireless communication method, a piconet is formed by a plurality of Bluetooth devices connected to perform wireless communication in accordance with the Bluetooth standard. Multiple Bluetooth devices consist of one master device and other slave devices, and one Bluetooth device belonging to one piconet as a slave device can be connected to belong to another piconet as a master device, Furthermore, this is a wireless communication method that enables connection by wireless communication between two piconets based on the wireless communication function of a Bluetooth device belonging to two piconets. The wireless communication method includes a step of performing connection processing between a master device and each slave device in a higher-level piconet by a Bluetooth core, a step in which a slave device receives a broadcast packet from a master device in a higher-order piconet, and a slave device of the higher-order piconet Is the master device of the lower piconet, the step of switching the connection relationship, the step of performing connection processing between the master device and each slave device in the lower piconet by the Bluetooth core, and the master device and all slave devices in the lower piconet Determining whether or not the connection relationship is established, and when the master device and all slave devices are connected in the lower-level piconet, the master device transmits a broadcast packet to all slave devices. It is configured.

  According to the above wireless communication method, each piconet establishes a connection between the master device and all of the plurality of slave devices and transmits a broadcast packet, thereby suppressing packet loss, such as a document file Effective for data transmission.

  According to a fourth wireless communication method (corresponding to claim 4), in the third method described above, the slave device preferably transmits a transmission wait request to the master device after receiving the broadcast packet. Features.

  According to the present invention, in a wireless communication method based on the Bluetooth standard, simultaneous distribution is possible based on a simple and inexpensive communication configuration, and a one-to-many broadcast communication method between Bluetooth devices is realized between multistage piconets. it can. Further, according to the first aspect of the present invention relating to the first wireless communication method, the real-time property of data transmission can be maintained, and real-time voice distribution and the like can be performed effectively. Furthermore, according to the third aspect of the present invention relating to the third wireless communication method, packet loss is suppressed by packet transmission between piconets and between Bluetooth devices, and a large amount of data such as a document file is reliably transmitted. Can do.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments (examples) of the present invention will be described below with reference to the accompanying drawings.

  A radio communication system in which the radio communication method according to the present invention is realized will be described with reference to FIG. FIG. 1 shows an example of the configuration of a scatternet in multi-hop communication. In FIG. 1, A, B, C, and D indicate four piconets as an example. In this illustrated example, piconet A is the highest-order piconet, piconets C and D are the lowest-order piconet, and piconet B is a piconet located in the middle. In the illustrated scatternet, as an example, the piconets A to D are constructed in a three-stage configuration from upper to lower. In the piconets A to D, a wireless communication relationship is formed by two piconets located on the upper side and the lower side. Also, a scatternet is constructed based on the connection relationship between piconets.

  In the above configuration, a three-stage piconet is shown, but the radio communication system to which the radio communication method according to the present invention is applied is not limited to this, and can be applied to a multistage piconet.

  Each of the wireless communication devices T1 to T10 illustrated in FIG. 1 is a Bluetooth device configured to perform wireless communication in accordance with the Bluetooth (Bluetooth) standard. Each of the piconets A to D includes a plurality of Bluetooth devices as elements. According to the principle of wireless communication according to the Bluetooth standard, a piconet is configured to include one master device and up to seven slave devices. Naturally, the master device and the slave device are the Bluetooth devices. Whether the Bluetooth device functions as a master device or a slave device is determined by the role assigned to the piconet to which the Bluetooth device is assigned.

  Specific examples of the wireless communication devices T1 to T10 include a mobile phone, a personal digital assistant, a personal computer, and the like. Since these wireless communication devices T1 to T10 function as Bluetooth devices, they are equipped with a Bluetooth standard wireless module. Thus, data transmission / reception is performed between these electronic devices according to the Bluetooth standard.

  The piconet A is composed of Bluetooth devices T1 to T4. In the piconet A, the Bluetooth device T1 is a master device, and the Bluetooth devices T2 to T4 are slave devices. The piconet B is composed of Bluetooth devices T2, T5 to T7. In the piconet B, the Bluetooth device T2 is a master device, and the Bluetooth devices T5 to T7 are slave devices. The piconet C is composed of Bluetooth devices T5 and T8. In the piconet C, the Bluetooth device T5 is a master device, and the Bluetooth device T8 is a slave device. The piconet D is composed of Bluetooth devices T6, T9, and T10. In the piconet D, the Bluetooth device T6 is a master device, and the Bluetooth devices T9 and T10 are slave devices.

  The master device T1 of the uppermost piconet A includes an information generation source and sets a base time. The Bluetooth device T2 belongs to two piconets A and B. The piconet A functions as a slave device, and the piconet B functions as a master device. The Bluetooth device T2 as the master device includes an information generation source and sets a base time. When the Bluetooth device T2 belongs to one piconet, the other piconet is set to the standby mode. The Bluetooth device T5 belongs to two piconets B and C. The piconet B functions as a slave device, and the piconet C functions as a master device. The Bluetooth device T5 as a master device includes an information generation source and sets a base time. When the Bluetooth device T5 belongs to one piconet, the other piconet is set to the standby mode. The Bluetooth device T6 belongs to two piconets B and D. The piconet B functions as a slave device, and the piconet D functions as a master device. The Bluetooth device T6 as a master device includes an information generation source and sets a base time. When the Bluetooth device T6 belongs to one piconet, the other piconet is set to the standby mode. In the above, the base time set by the lower master device is set with reference to the base time set by the upper master device. Furthermore, the base time can be set by the master device of the highest piconet, and the lower master device can use the base time received from the upper piconet as it is.

  In a wireless communication system according to the Bluetooth standard, each of the Bluetooth devices T1 to T10, that is, each node, can belong to only one piconet and cannot belong to two piconets at the same time. In order for each Bluetooth device of each piconet to perform multi-hop communication over two piconets, the Bluetooth devices belonging to the upper and lower two piconets need to repeat the following procedure.

Step S1: Connect to a higher-level master device as a slave device.
Step S2: Receive a packet from an upper master device.
Step S3: Change the connection with the master device to the standby mode.
Step S4: A slave device is connected by a lower-level piconet that is itself a master device. Step S5: The packet is transmitted to the lower slave device.
Step S6: Change the connection with the slave slave device to the standby mode.

  In the wireless communication system according to the Bluetooth standard shown in FIG. 1, as described above, Bluetooth devices belonging to the upper and lower two piconets cannot belong to the two piconets at the same time. Therefore, according to the wireless communication method according to the present invention, in the Bluetooth devices belonging to the upper piconet and the lower piconet, simultaneous broadcast packets transmitted from the master device of the upper piconet are connected to the lower piconet from the upper piconet. It is configured so that it can be switched and simultaneously delivered to slave devices of the lower piconet. This makes it possible to implement a one-to-many broadcast communication method between Bluetooth devices between multistage piconets. As described below, there are two types of switching methods, ie, two types of transfer methods (inter-piconet synchronous transfer method and inter-piconet asynchronous transfer method) for switching the connection relationship between the upper piconet and the lower piconet. Conceivable.

  First, a first embodiment of a wireless communication method according to the present invention will be described with reference to FIGS. The wireless communication method according to the first embodiment is a simultaneous communication wireless communication method using an inter-piconet synchronous transfer method.

  FIG. 2 is a flowchart, and FIGS. 3 and 4 are sequence diagrams regarding signal transmission / reception and data distribution between Bluetooth devices. FIG. 3 shows a four-layer sequence in which data distribution is performed sequentially between three stages of piconets (A, B, C) from the upper level to the lower level. FIG. 4 shows a three-layer sequence in which simultaneous data distribution is performed sequentially between two-stage piconets (A, B) from the upper level to the lower level.

  The flowchart of FIG. 2 shows a processing process for simultaneous distribution of predetermined information in the piconet A and subsequent simultaneous distribution of the same predetermined information in the piconet B, for example. Therefore, the connection from the simultaneous distribution in the piconet A to the simultaneous distribution in the piconet B is performed through the Bluetooth devices T2 belonging to the two piconets A and B. In the flowchart of FIG. 2, a processing process (S11 to S15) in the piconet A and a processing process (S16 to S19) in the piconet B are shown.

  First, simultaneous distribution of predetermined information (broadcast packet) in the piconet A will be described. In the piconet A, the master device T1 including the information generation source sets a base time. The master device T1 transmits the base time only once to the slave devices T2 to T4 belonging to the piconet A immediately before transmitting the first broadcast packet.

  In FIG. 2, step S11 executes a connection process in the upper piconet A by the Bluetooth core. That is, a connection relationship based on the Bluetooth standard is formed between the master device T1 which is a Bluetooth device and the slave devices T2 to T4. For example, in FIG. 3, a signal transmission / reception relationship between two Bluetooth devices indicated by reference numeral 31 is a relationship formed by a connection process (step S11) by the Bluetooth core.

  When the connection process (step S11) by the Bluetooth core is completed, the base time is transmitted from the master device T1 to each of the slave devices T2 to T4. Each slave device T2 to T4 receives the base time from the master device T1 (step S12). The value of the base time is the time from step S1 to S6 described above. In the inter-piconet synchronous transfer method, each of the slave devices T2 to T4 operates based on the above steps S1 to S6 according to the base time as long as the above-described conditions are satisfied. Steps S13, S14, and S15 shown in FIG. 2 differ depending on the roles of the slave devices T2 to T4. In the case of mere slave devices T3 and T4, after receiving the broadcast packet (step S13), the determination is NO in decision step S14 and the process ends. The slave device T2 functioning as the master device in the piconet B receives the broadcast packet (step S13), and then becomes YES in the determination step S14 and step S15 is executed. Step S13 corresponds to step S2 described above.

  With regard to the delivery of broadcast packets from the master device T1 to the slave devices T2 to T4 in the piconet A, the slave devices T3 and T4 end in steps S11 to S14. About slave apparatus T2, since it is YES at step S14 after step S11-S14, it transfers to step S16 via step S15. Step S15 corresponds to step S3 described above. In step S15, the connection with the upper piconet A is changed to the standby mode.

  In the sequence diagram of FIG. 3, the vertical axis indicates a sequence of four layers by the master device T1, the slave device T2, the slave device T5, and the slave device T8 from the top to the bottom, and the horizontal axis indicates the time axis. . In the first sequence 30 between the master device T1 and the slave device T2 in the piconet A, the Bluetooth core connection process 31 (step S11), the base time transmission 32 (step S12), and the broadcast packet transmission 33 (step S13). ), Changing the connection to the standby mode (34: Step S15). When the connection is changed to the standby mode (34) in the slave device T2, the slave device T2 functions as a master device in the piconet B next.

  Next, simultaneous delivery of broadcast packets in the piconet B will be described. In the piconet B, the master device T2 performs simultaneous distribution to the slave devices T5 to T7. In the piconet B, the master device T2 including the information generation source sets a base time. The master device T2 transmits the base time only once to the slave devices T5 to T7 belonging to the piconet B immediately before transmitting the first broadcast packet.

  In FIG. 2, step S16 executes a connection process in the lower piconet B by the Bluetooth core. That is, a connection relationship based on the Bluetooth standard is formed between the master device T2 which is a Bluetooth device and the slave devices T5 to T7. For example, in FIG. 3, the signal transmission / reception relationship indicated by reference numeral 41 between the slave device (master device) T2 and the slave device T5 is the relationship formed by the connection processing (step S16) by the Bluetooth core.

  When the connection process (step S16) by the Bluetooth core is completed, the master device T2 transmits a base time to each of the slave devices T5 to T7 (step S17). In response to this, each of the slave devices T5 to T7 receives the base time from the master device T2. The value of the base time is the time from step S1 to S6 described above. In the inter-piconet synchronous transfer system, each of the slave devices T5 to T7 operates based on the above steps S1 to S6 according to the base time as long as the above-described conditions are satisfied.

  Steps S17, S18, and S19 shown in FIG. 2 are processing functions of the master device T2 in the piconet B. The master device T2 transmits the base time (42: Step S17), transmits a broadcast packet to each of the slave devices T5 to T7 (43: Step S18), and changes the connection with the lower slave device of the piconet B to the standby mode. (44: Step S19). When step S19 is completed in the master device T2, a connection relationship with the higher-level piconet A is formed. Accordingly, the state of the Bluetooth device T2 functions as a slave device of the piconet A, and executes a sequence (a series of signal / information transmission / reception) indicated by reference numeral 35 in FIG. This sequence 35 is the same as the previous sequence 30 except that the base time is not transmitted. Thus, the Bluetooth device T2 executes the sequences 30 and 35 as slave devices in the piconet A, and executes the sequences 40 and 45 as master devices in the piconet B. In the sequence 40, the base time is transmitted, but in the sequence 45, the base time is not transmitted. Each of the above sequences (30, 35, 40, 45, etc.) is executed within a certain connection time range based on the base time.

  In FIG. 3, between the Bluetooth device T5 and the Bluetooth device T8, the same signal transmission / reception and data distribution as described above are performed between the piconets B and C. Similarly, with respect to data distribution via Bluetooth devices belonging to the other two upper and lower piconets, broadcast packets are transmitted and received based on the aforementioned inter-piconet synchronous transfer method.

  In FIG. 4, sequential simultaneous data distribution is performed between the piconets A and B as described above. In this sequence diagram, the vertical axis indicates a sequence of three layers by the master device T1, the slave device T2, and the slave devices T5 and T6 from the upper level to the lower level, and the horizontal axis indicates the time axis. Between the master device T1 and the slave device T2 in the piconet A, the Bluetooth core connection process 31 (step S11), base time transmission 32 (step S12), broadcast packet transmission 33 (step S13), and connection in standby mode (34: Step S15) is executed. When the connection is changed to the standby mode (34) in the slave device T2, the slave device T2 functions as a master device in the piconet B. After that, in the piconet B, the simultaneous delivery sequences 40 and 45 are executed between the master device T2 and the lower slave devices T5 and T6. The slave device T5 needs to transmit data to the slave device T8, which is a lower-level piconet, after receiving data from the master device T2, but the illustration thereof is omitted in FIG.

  In the wireless communication method according to the first embodiment described above, the data is not retransmitted and lost to the slave device that could not be reconnected within the set base time (for example, state 46 shown in FIG. 4). ). However, according to the wireless communication method of the first embodiment, the real-time property can be maintained, which is an effective method for distributing real-time audio.

  Next, a second embodiment of the wireless communication method according to the present invention will be described with reference to FIGS. The wireless communication method according to the second embodiment is a simultaneous communication wireless communication method using an inter-piconet asynchronous transfer method.

  FIG. 5 is a flowchart, and FIGS. 6 and 7 are sequence diagrams relating to signal transmission / reception and data distribution between Bluetooth devices. FIG. 6 shows a four-layer sequence in which data distribution is performed sequentially between three stages of piconets (A, B, C) from the upper level to the lower level. FIG. 7 shows a three-layer sequence in which simultaneous data distribution is performed sequentially between two-stage piconets (A, B) from the upper level to the lower level. 6 corresponds to FIG. 3, and FIG. 7 corresponds to FIG.

  The flowchart of FIG. 5 shows a processing process of simultaneous distribution of predetermined information in, for example, piconet A and subsequent simultaneous distribution of the same predetermined information in piconet B. The connection from the simultaneous delivery in piconet A to the simultaneous delivery in piconet B is made via the Bluetooth device T2 belonging to the two piconets A and B. In the flowchart of FIG. 2, a process process (S21 to S25) in the piconet A and a process process (S26 to S30) in the piconet B are shown.

  First, simultaneous distribution of predetermined information (broadcast packet) in the piconet A will be described. In the inter-piconet asynchronous transfer method, in each piconet, the master device records connection information of the slave device every time. If there is an unconnected slave device at the next connection, the master device transmits a broadcast packet after waiting for all slave devices to be established.

  In FIG. 5, step S21 executes connection processing in the upper piconet A by the Bluetooth core. That is, a connection relationship based on the Bluetooth standard is formed between the master device T1 which is a Bluetooth device and the slave devices T2 to T4. For example, in FIG. 6, the signal transmission / reception relationship between two Bluetooth devices indicated by reference numeral 51 is the relationship formed by the connection processing (step S21) by the Bluetooth core.

  When the connection process (step S21) by the Bluetooth core is completed, a broadcast packet is transmitted from the master device T1 to each of the slave devices T2 to T4 (step S22). At this time, in the inter-piconet asynchronous transfer method, in the piconet A, the master device T1 records the connection information of the slave device every time, and when there is an unconnected slave device at the next connection, all the slave devices Wait for it to establish and send a broadcast packet.

  In the case of mere slave devices T3 and T4, after receiving the broadcast packet (step S22), the determination is NO in decision step S23 and the process ends.

  The slave device T2 that functions as the master device in the piconet B receives the broadcast packet (step S22), and then the determination in step S23 is YES and steps S24 and S25 are executed. Step S25 corresponds to step S2 described above.

  Regarding delivery of broadcast packets from the master device T1 to the slave devices T2 to T4 in the piconet A, the slave devices T3 and T4 end in steps S21 to S23. Since the slave device T2 is YES in step S23 after steps 21 to S23, the process proceeds to step S26 via steps S24 and S25. Step S25 corresponds to step S3 described above. In step S24, a transmission wait request is transmitted to the master device T1. In step S25, the connection with the upper piconet A is changed to the standby mode.

  In the sequence diagram of FIG. 6, the vertical axis indicates a four-layer sequence from the upper stage toward the lower stage by the master device T1, the slave device T2, the slave device T5, and the slave device T8, and the horizontal axis indicates the time axis. . Between the master device T1 and the slave device T2 in the piconet A, the Bluetooth core connection process 51 (step S21), broadcast packet transmission 52 (step S22), transmission wait request transmission (reception) 53 (step S24), The connection is changed to the standby mode (54: Step S25). When the connection is changed to the standby mode (54) in the slave device T2, the slave device T2 functions as a master device in the piconet B next.

  Next, simultaneous delivery of broadcast packets in the piconet B will be described. In the piconet B, the master device T2 performs simultaneous distribution to the slave devices T5 to T7.

  In FIG. 5, a step S26 executes a connection process in the lower piconet B by the Bluetooth core. That is, a connection relationship based on the Bluetooth standard is formed between the master device T2 which is a Bluetooth device and the slave devices T5 to T7. For example, in FIG. 6, the signal transmission / reception relationship indicated by reference numeral 51 between the slave device (master device) T2 and the slave device T5 is the relationship formed by the connection processing (step S26) by the Bluetooth core.

  When the connection process (step S26) by the Bluetooth core is completed, the master device T2 determines whether or not any arbitrary slave device is connected with respect to the connection with each of the slave devices T5 to T7 (step S27). When the determination step S27 is NO, step S26 is executed again. All connections in the piconet B are established through steps S26 and S27. That is, in the inter-piconet asynchronous transfer method, in the piconet B, the master device T2 records the connection information of the slave devices T5 to T7 every time, and waits for the connection of all the slave devices to be established, and transmits a broadcast packet (step) S28). The sequence 61 between the master device T2 and the slave device T5 shown in FIG. 6 has substantially the same content as the sequence 55 described above.

  Thereafter, steps S29 and S30 are executed. In step S28, the master device T2 receives a transmission wait request from a lower slave device. In step S30, the master device T2 changes the connection with the lower level to the standby mode.

  When step S30 is completed in the master device T2, a connection relationship with the higher-level piconet A is formed. Therefore, the state of the Bluetooth device T2 functions as a slave device of the piconet A and shifts to a sequence indicated by reference numeral 55 in FIG. This sequence 55 is the same as the previous sequence 55. In this way, the Bluetooth device T2 executes the sequence 55 as a slave device in the piconet A, and executes the sequence 61 as a master device in the piconet B.

  In FIG. 6, between the Bluetooth device T5 and the Bluetooth device T8, signal transmission / reception and data distribution similar to those described above are performed between the piconets B and C. Similarly, with respect to data distribution via other Bluetooth devices belonging to two other upper and lower piconets, broadcast packets are transmitted and received based on the above-described asynchronous transfer scheme between piconets.

  In FIG. 7, as described above, simultaneous simultaneous data distribution is performed between piconets A and B based on the asynchronous transfer method between piconets. In this sequence diagram, the vertical axis indicates a sequence of three layers by the master device T1, the slave device T2, and the slave devices T5 and T6 from the upper level to the lower level, and the horizontal axis indicates the time axis. Between the master device T1 and the slave device T2 in the piconet A, the Bluetooth core connection process 51 (step S21), broadcast packet transmission 52 (step S22), transmission wait request transmission (reception) 53 (step S24), The connection is changed to the standby mode (54: Step S25). When the connection is changed to the standby mode (54) in the slave device T2, the slave device T2 functions as a master device in the piconet B. After that, in the piconet B, the simultaneous delivery sequence 61 based on the inter-piconet asynchronous transfer method is executed between the master device T2 and the lower slave devices T5 and T6. In FIG. 7, even if the state 62 occurs and the Bluetooth standard connection fails between the master device T2 and the slave device T6, the master device T2 stores the previous connection terminal and waits until all of them are connected. Then, broadcast packets are transmitted after all are connected. Note that the slave device T5 needs to transmit data to the slave device T8, which is a lower piconet, after receiving data from the master device T2, but this is not shown in FIG.

  In the wireless communication method according to the second embodiment described above, a broadcast packet is transmitted after the connection between the master device and all slave devices is established in each piconet. As a result, packet loss can be suppressed, which is effective for transferring data such as document files.

  The configurations, shapes, sizes, and arrangement relationships described in the above embodiments are merely schematically shown to the extent that the present invention can be understood and implemented. Therefore, the present invention is not limited to the described embodiments, and can be variously modified without departing from the scope of the technical idea shown in the claims.

  The present invention is used in a wireless communication method based on the Bluetooth standard as a multi-hop broadcast method.

It is a system diagram which shows an example of a structure of the scatter net in the multihop communication to which the radio | wireless communication method which concerns on this invention is applied. It is a flowchart which shows 1st Embodiment of the radio | wireless communication method which concerns on this invention. It is a figure which shows the sequence of 4 hierarchies in which data distribution is performed sequentially among the three stages of piconets (A, B, C) from the upper level to the lower level in the wireless communication method according to the first embodiment. It is a figure which shows the sequence of the three layers in which the data delivery of simultaneous delivery is performed sequentially between the piconet (A, B) of two steps from a high level to a low level by the radio | wireless communication method which concerns on 1st Embodiment. It is a flowchart which shows 2nd Embodiment of the radio | wireless communication method which concerns on this invention. It is a figure which shows the sequence of 4 layers in which data delivery is performed sequentially between the three steps of piconets (A, B, C) from the upper level to the lower level in the wireless communication method according to the second embodiment. It is a figure which shows the sequence of 3 layers in which the data distribution of simultaneous delivery is performed sequentially between two steps of piconets (A, B) from the upper level to the lower level in the wireless communication method according to the second embodiment.

Explanation of symbols

A to D piconet T1 to T10 Bluetooth device

Claims (4)

A plurality of Bluetooth devices connected to perform wireless communication according to the Bluetooth standard form a piconet, and the plurality of Bluetooth devices in the piconet are composed of one master device and other slave devices, and are slaved to one piconet. One Bluetooth device belonging to a device can be connected to belong to another piconet as a master device, and wireless communication is performed between the two piconets based on the wireless communication function of the Bluetooth device belonging to the two piconets. In the wireless communication method that enables connection by
The master device of the upper piconet sets the base time as an information source,
Performing a connection process between the master device and each slave device in the higher-level piconet by a Bluetooth core;
The slave device in the higher-level piconet receives the base time from the master device;
The slave device in the higher-level piconet receives a broadcast packet from the master device;
When the slave device of the upper piconet is a master device of the lower piconet, switching the connection relationship;
Performing a connection process between the master device and each slave device in the lower-level piconet by a Bluetooth core;
Transmitting the base time from the master device to the slave device in the lower piconet;
The master device in the lower piconet transmits a broadcast packet to the slave device;
A wireless communication method comprising:   2. The transmission of the base time from the master device to the slave device in each of the upper piconet and the lower piconet is performed only once immediately before the first broadcast packet is transmitted. Wireless communication method. A plurality of Bluetooth devices connected so as to perform wireless communication according to the Bluetooth standard form a piconet, and the plurality of Bluetooth devices in the piconet are composed of one master device and other slave devices, and in one piconet. One Bluetooth device belonging as a slave device can be connected as a master device so as to belong to another piconet, and further, wirelessly between the two piconets based on the wireless communication function of the Bluetooth device belonging to the two piconets. In a wireless communication method that enables connection by communication,
Performing a connection process between the master device and each slave device in a higher-level piconet by the Bluetooth core;
The slave device in the higher-level piconet receives a broadcast packet from the master device;
When the slave device of the upper piconet is a master device of the lower piconet, switching the connection relationship;
Performing a connection process between the master device and each slave device in the lower-level piconet by a Bluetooth core;
Determining whether or not a connection relationship between the master device and all slave devices is formed in the lower piconet;
When the master device and all the slave devices are connected in the lower piconet, the master device transmits a broadcast packet to all the slave devices;
A wireless communication method comprising: The wireless communication method according to claim 3, wherein the slave device transmits a transmission wait request to the master device after receiving the broadcast packet.

Images