Field of the Invention

The present disclosure relates to the field of communications, in particular to a gateway for a mesh network.

Background of the Invention

Conventionally, in the field of communications networks using indoor Wi-Fi or Bluetooth, a transmitting device usually communicates with a receiving device to transfer information. Therefore, in order to grasp device or asset location, transmitting devices, such as tags, are installed on devices or assets, and receiving devices, such as gateways, are provided in a one-to-one correspondence with transmitted radio waves.

A gateway generally includes a housing and a plurality of antennas provided in the housing, so that the gateway can receive electric waves from or transmit electric waves to external devices via the antennas.

However, for a conventional gateway, the distribution of antennas in the housing usually leads to weak radio waves, packet loss, and even a signal reception blind angle in a certain direction. This undoubtedly seriously affects the signal receiving performance of the gateway.

Therefore, there is an urgent need for a gateway for a mesh network with high signal receiving performance.

Summary of the Invention

An objective of the present disclosure is to provide a gateway for a mesh network with high signal receiving performance. The gateway for a mesh network of the present disclosure uses a quadrangular housing.

Three corners in the housing are respectively provided with at least one antenna.

For each of the three comers in the housing, an extension line in a length direction of the antenna provided at the corner intersects with two sides constituting the comer.

According to such a structure, by the reasonable arrangement of the antennas in a limited space, the isolation between signals is improved, the interaction between signals of the antennas is reduced, and the signal receiving performance of the gateway is improved.

Preferably, the antennas are planar inverted F-shaped antennas.

Here, a planar inverted F-shaped antenna as a whole has a shape like an inverted English letter F, hence the name. The basic structure of the planar inverted F-shaped antenna employs a planar radiating unit as a radiator and the ground as a reflecting surface. The radiator is provided thereon with two pins close to each other, the two pins being respectively used for grounding and used as a feed point. Since metal planar inverted F-shaped antennas can change feed positions to concentrate signal radiation in a front direction of the gateway, the signal receiving capability of the gateway can be further improved.

Preferably, the antennas are provided on a printed circuit board, wherein a height of each of the antennas relative to the printed circuit board is greater than a height of other components provided on the printed circuit board relative to the printed circuit board.

According to such a structure, since the height of each of the antennas is greater than the height of other components on the printed circuit board, the bandwidth of the antennas can be widened, which can further improve the signal transmission capability of the gateway.

Preferably, the extension lines in the length direction of the antennas provided at two adjacent comers of the three corners are orthogonal to each other.

According to such a structure, since the antennas provided at two adjacent corners of the three comers in the housing are arranged orthogonally to each other, the isolation between the orthogonally arranged antennas is high. Hence, by the reasonable arrangement of the antennas in the relatively limited PCB space of the gateway, the isolation can be above -15 dB, and the interaction between signals of the antennas is reduced.

Preferably, the gateway is installed on a top of a wall with a bottom of the housing facing upward.

According to such a structure, the gateway is installed on a top of a wall in a ceiling suspended manner to cover all areas of a room as much as possible, and the use of metal planar inverted F-shaped antennas can make signal radiation concentrated in a front direction of the gateway. In this way, signal coverage in the room is good, and signal radiation on the back of the gateway is minimized, which reduces the mutual interference with a device upstairs.

Preferably, the gateway is capable of communicating with a lite-gateway mounted with a plurality of Bluetooth chips, wherein the lite-gateway has only a part of functions of the gateway.

According to such a configuration, since lite-gateways for message relay are added between Bluetooth tags and gateways, long distance transmission of messages can be realized. In addition, since lite-gateways have only a part of the functions of gateways, the deployment cost of lite-gateways is lower than the deployment cost of gateways, which can effectively reduce the deployment cost of the mesh network.

Preferably, the gateway is capable of communicating with a lite-gateway mounted with at least three Bluetooth chips. Preferably, the gateway includes: a first Bluetooth chip which performs message scanning on a first scan channel; a second Bluetooth chip which performs message scanning on a second scan channel; a third Bluetooth chip which performs message scanning on a third scan channel; and a processor which communicates with the first Bluetooth chip, the second Bluetooth chip, and the third Bluetooth chip respectively, wherein the first Bluetooth chip, the second Bluetooth chip and the third Bluetooth chip simultaneously perform message scanning on their respective scan channels.

Preferably, the first Bluetooth chip, the second Bluetooth chip and the third Bluetooth chip of the gateway broadcast the sub-net information of the sub-net where the gateway is located on their respective scan channels.

Preferably, the lite-gateway includes: a fourth Bluetooth chip which performs message scanning on a first scan channel; a fifth Bluetooth chip which performs message scanning on a second scan channel; and a sixth Bluetooth chip which performs message scanning on a third scan channel, wherein the fourth Bluetooth chip, the fifth Bluetooth chip, and the sixth Bluetooth chip simultaneously perform message scanning on their respective scan channels.

According to the above configuration, the gateway includes three Bluetooth chips that simultaneously perform message scanning on their respective scan channels, which improves scanning efficiency and message reception rate while effectively reducing the interference of scanning processes performed on other wireless scan channels to the scanning process of the gateway. In the same way, the lite-gateway includes three Bluetooth chips that simultaneously perform message scanning on their respective scan channels, which improves scanning efficiency and message reception rate while effectively reducing the interference of scanning processes performed on other wireless scan channels to the scanning process of the lite-gateway.

In other words, the antennas provided at different comers work at different frequencies, which can further reduce the interference between signals and ensure that the gateway and the lite-gateway have relatively high receiving sensitivity.

Preferably, a center frequency of the first scan channel is 2402 MHz, a center frequency of the second scan channel is 2426 MHz, and a center frequency of the third scan channel is 2480 MHz.

According to the above configuration, the center frequencies of the scan channels of the three Bluetooth chips of the gateway or lite-gateway are set to 2402 MHz, 2426 MHz, and 2480 MHz respectively. WiFi modules of the gateway include a 2.4G WiFi module and a 5G WiFi module. The 2.4G WiFi module only affects a part of the scan channels of the Bluetooth chips, which can effectively reduce the interference of the scanning process performed on the 2.4G wireless communication channel to the scanning process of the gateway or lite-gateway.

Brief Description of the Drawings

The scope of the present disclosure can be better understood by reading the detailed description of the following exemplary embodiments in conjunction with the accompanying drawings. The drawings included are:

Fig. 1 shows a schematic diagram of an internal structure of a housing of a gateway for a mesh network according to Embodiment One of the present disclosure.

Fig. 2 shows a schematic diagram of a structure of antennas provided on a printed circuit board.

Fig. 3 shows a schematic diagram of isolation of antennas of the gateway for a mesh network according to Embodiment One of the present disclosure.

Fig. 4 shows a schematic diagram of pattern synthesis of the antennas of the gateway for a mesh network according to Embodiment One of the present disclosure. Fig. 5 shows a schematic diagram of installation of the gateway for a mesh network according to Embodiment One of the present disclosure.

Fig. 6 shows a schematic diagram of a topology of a Bluetooth low energy mesh network in the prior art.

Fig. 7 shows a schematic diagram of a topology of a Bluetooth low energy mesh network according to Embodiment Two of the present disclosure.

Fig. 8 shows a schematic diagram of a scanning strategy of a gateway in the prior art.

Fig. 9 shows a schematic diagram of a structure of a gateway in Embodiment Two of the present disclosure.

Fig. 10 shows a schematic diagram of a scanning strategy of the gateway in Embodiment Two of the present disclosure.

Fig. 11 shows a schematic flowchart of a sub-net configuration method for a Bluetooth low energy mesh network.

Fig. 12 shows a schematic flowchart of a method for determining a target sub-net by a lite-gateway according to sub-net information.

Fig. 13 shows a schematic diagram of an example of the sub-net configuration method for a Bluetooth low energy mesh network.

Fig. 14 shows a schematic flowchart of a message uploading method based on a Bluetooth low energy mesh network.

Fig. 15 shows a schematic diagram of an example of the message uploading method based on a Bluetooth low energy mesh network. Fig. 16 shows a schematic flowchart of a Bluetooth tag location determination method based on a Bluetooth low energy mesh network.

Detailed Description of the Embodiments

In order to make the objective, technical solutions and advantages of the present disclosure clearer, implementation methods of the present disclosure will be described below in detail in conjunction with the accompanying drawings and embodiments, so as to fully understand and implement the implementation process regarding how the present disclosure applies technical means to solve technical problems and achieve technical effects.

For a conventional gateway, the distribution of antennas in a housing usually leads to weak radio waves, packet loss, and even a signal reception blind angle in a certain direction. This undoubtedly seriously affects the signal receiving performance of the gateway. To solve this problem, the embodiments of the present disclosure provide a gateway for a mesh network with high signal receiving performance.

Embodiment One

Fig. 1 shows a schematic diagram of an internal structure of a housing 10 of a gateway 1 for a mesh network according to Embodiment One of the present disclosure. Fig. 2 shows a schematic diagram of a structure of antennas provided on a printed circuit board 30. As shown in Fig. 1, the gateway 1 for a mesh network according to the embodiment of the present disclosure uses a quadrangular housing 10. The gateway 1 includes at least three antennas accommodated in the housing 10. Referring to Fig. 1, the gateway 1 includes three antennas, namely, a first antenna 21, a second antenna 22, and a third antenna 23. The antennas 21, 22, and 23 are distributed at three comers in the housing 10. The housing 10 includes four corners, namely, a first corner 11, a second corner 12, a third comer 13, and a fourth corner 14. The first antenna 21 is located at the first comer 11 in the housing 10, and an extension line of the first antenna 21 in a length direction intersects with two sides constituting the first corner 11. The second antenna 22 is located at the second comer 12 in the housing 10, and an extension line of the second antenna 22 in a length direction intersects with two sides constituting the second comer 12. The third antenna 23 is located at the third comer 13 in the housing 10, and an extension line of the third antenna 23 in a length direction intersects with two sides constituting the third corner 13.

In addition, in a case where three or more antennas are accommodated inside the housing 10, at least one of the above three corners in the housing 10 is provided with two antennas. In this case, the two antennas may be arranged in parallel or non-parallel to each other, as long as it is ensured that extension lines of the two antennas in a length direction both intersect with two sides constituting the corner.

According to such a structure, by the reasonable arrangement of the antennas in a relatively limited space, the isolation between signals is improved, the interaction between signals of the antennas is reduced, and the signal receiving performance of the gateway 1 is improved.

In a preferred embodiment of the present disclosure, referring to Fig. 1 or Fig. 2, the extension line of the first antenna 21 in the length direction and the extension line of the second antenna 22 in the length direction are orthogonal to each other, and the extension line of the second antenna 22 in the length direction and the extension line of the third antenna 23 in the length direction are orthogonal to each other.

According to such a structure, since the antennas provided at two adjacent corners of the three corners in the housing 10 are arranged orthogonally to each other, the isolation between the orthogonally arranged antennas is high. Isolation data of the antennas is shown in Fig. 3. By the reasonable arrangement of the antennas in the relatively limited space of the PCB of the gateway 1, the isolation can be above -15dB, and the interaction between signals of the antennas are reduced. In addition, received signals of the antennas have good complementary coverage capabilities. Referring to pattern synthesis of the three antennas in XOY (theta=90°) shown in Fig. 4, as can be seen from coverage of the 2D pattern, the antennas of the gateway 1 can receive data packets from different directions without particularly weak signals in a certain direction. For a certain direction with poor coverage of an antenna, the other two antennas can implement supplementary coverage. In other words, there is no reception blind angle in any direction, which ensures omnidirectional receiving performance and reduces possible packet loss due to weak signals in some directions.

In a preferred embodiment of the present disclosure, referring to Fig. 1 and Fig. 2, the antennas included in the gateway 1 are all planar inverted F-shaped antennas. Here, a planar inverted F-shaped antenna as a whole has a shape like an inverted English letter F, hence the name. The basic structure of the planar inverted F-shaped antenna employs a planar radiating unit as a radiator and the ground as a reflecting surface. The radiator is provided thereon with two pins close to each other, the two pins being respectively used for grounding and used as a feed point. Since metal planar inverted F-shaped antennas can change feed positions to concentrate signal radiation in a front direction of the gateway 1, the signal receiving capability of the gateway 1 can be further improved.

In a preferred embodiment of the present disclosure, referring to Fig. 1 and Fig. 2, the antennas included in the gateway 1 are all provided on the printed circuit board 30. A height of each antenna relative to the printed circuit board 30 is greater than a height of other components provided on the printed circuit board 30 relative to the printed circuit board 30. In particular, a height difference between each antenna and other components is greater than 10 mm.

According to such a structure, since the height of each antenna is larger than the height of other components on the printed circuit board 30, the bandwidth of the antennas can be widened, which can further improve the signal transmission capability of the gateway 1.

In a preferred embodiment of the present disclosure, the gateway 1 is installed in a ceiling suspended manner. Referring to Fig. 5, the gateway 1 is installed on a top of a wall with a bottom 15 of the housing 10 facing upward.

According to such a structure, the gateway 1 is installed on a top of a wall in a ceiling suspended manner to cover all areas of a room as much as possible, and the use of metal planar inverted F-shaped antennas can make signal radiation concentrated in the front direction of the gateway 1. In this way, signal coverage in the room is good, and signal radiation on the back of the gateway 1 is minimized, which reduces the mutual interference with a device upstairs. In addition, the planar inverted F-shaped antennas used in this embodiment can reduce signal interference better than conventional printed antennas. Specifically, a printed antenna has radiation energy in Z-axis positive direction basically the same as in Z-axis negative direction, so the energy of a printed antenna in the negative direction is less than the energy of a metal planner inverted F-shaped antenna in the negative direction, and if the radiation in the Z-axis positive direction is stronger, it may cause mutual interference with the upstairs.

The above gateway 1 can be used to form a Bluetooth mesh network. A Bluetooth mesh network and a sub-net configuration method, message uploading method and Bluetooth tag location determination method based on the Bluetooth mesh network will be described in detail below.

It should be noted that the following embodiments are described in detail by taking a Bluetooth low energy (BLE) mesh network as an example.

Embodiment Two

In traditional design, the BLE communication is peer-to-peer. BLE tags or sensor nodes communicate directly with gateways. As shown in Fig. 6, a tag communicates with a cloud server via two gateways respectively. With this communication method, due to the hardware limitation of BLE technology, messages cannot be transmitted for long distance and gateways must be deployed very close to BLE tags to receive BLE messages sent from BLE tags. In addition, due to the high cost and high deployment density of gateways, the deployment cost of the entire network is high.

In order to solve the above technical problems existing in the prior art, the embodiment of the present disclosure provides a BLE mesh network, which can transmit messages for long distance and has low deployment cost.

The BLE mesh network of this embodiment includes a plurality of sub-nets. Each sub-net includes one gateway and at least one lite-gateway. Here, gateways serve as access devices, and lite-gateways serve as relay devices. Lite-gateways only have a portion of the functions of gateways, and thus the deployment cost of lite-gateways is lower than the deployment cost of gateways. Gateways communicate with a cloud server. Each lite-gateway may communicate with a gateway directly, or may communicate with a gateway via other lite-gateways. Messages output by Bluetooth tags are relayed to gateways via one or more lite-gateways, and then gateways process the received messages and upload the processed messages to the cloud server for storage and analysis.

Fig. 7 shows a schematic diagram of a topology of a BLE mesh network according to Embodiment Two of the present disclosure. Referring to Fig. 7, a BLE mesh network 200 includes a sub-net 201, a sub-net 202, and a sub-net 203. The structure of the sub-net is described below by taking the sub-net 201 as an example. The sub-net 201 includes gateway GW1 and two lite-gateways, namely, LGW1 and LGW2. Tag TAG1 communicates with gateway GW1 via lite-gateway LGW1. Tag TAG2 communicates with gateway GW1 via lite-gateway LGW2. Gateway GW1 communicates with a cloud server 100. Lite-gateways belonging to the same sub-net may not communicate with each other (for example, lite-gateways in the sub-net 201), or may communicate with each other (for example, lite-gateways in the sub-net 202 and in the sub-net 203). This is not limited in this embodiment of the present disclosure.

In this embodiment, a lite-gateway has only a part of the functions of a gateway, such as message receiving function, message sending function, and message filtering function. The functions of the lite-gateway are not limited to this. The lite-gateway may further have a function of the gateway of assisting in locating. The function of assisting in locating refers to assisting in locating based on received signal strength indication (RSSI).

When applying the BLE mesh network of this embodiment, since lite-gateways for message relay are added between Bluetooth tags and gateways, messages can be relayed by lite-gateways and then transmitted to gateways deployed far away, so that long distance transmission of messages can be realized. In addition, since lite-gateways have only a part of the functions of gateways, the deployment cost of lite-gateways is lower than the deployment cost of gateways, which effectively reduces the deployment cost of the BLE mesh network.

This embodiment of the present disclosure is mainly to build a simple, reliable, and low-cost wireless transmission network, to solve the problem of transmission distance limitation of a BLE mesh network, and to assist in locating asset location. The BLE mesh network of the embodiment of the present disclosure enables many-to-many (M: M) device communications to create large-scale device networks. The embodiment of the present disclosure is suited for building automation, asset management system, sensor networks, and other IoT solutions where tens, hundreds, or thousands of devices need reliable and secure communication for long distance transmission on a large scale.

Fig. 8 shows a schematic diagram of a scanning strategy of a gateway in the prior art. As shown in Fig. 8, the gateway uses a single BLE chip to scan three scan channels in a poll manner. The BLE chip first performs message scanning on a first scan channel (scan channel 37 with a center frequency of 2402MHz), then performs message scanning on a second scan channel (scan channel 38 with a center frequency of 2426MHz), and subsequently performs message scanning on a third scan channel (scan channel 39 with a center frequency of 2480MHz). Next, the BLE chip repeats the above scanning process. When message scanning is performed on each scan channel, the time period of each scan is determined according to scan interval and scan window parameters.

However, when the gateway further includes a 2.4G WiFi module (the gateway in this embodiment includes a 2.4G WiFi module and a 5G WiFi module), the wireless scanning of the 2.4G WiFi module will interfere with one or two of the three scan channels of the BLE chip, which reduces the reliability of data transmission.

In order to solve the above problem, in the embodiment of the present disclosure, the internal structures of the gateway and the lite-gateway are improved. Fig. 9 shows a schematic diagram of a structure of a gateway according to the embodiment of the present disclosure. Fig. 10 shows a schematic diagram of a scanning strategy of the gateway according to the embodiment of the present disclosure. In a preferred embodiment of the present disclosure, referring to Fig. 9 and Fig. 10, the gateway includes a first BLE chip, a second BLE chip, a third BLE chip, and a processor. The first BLE chip perform message scanning on a first scan channel (scan channel 37 with a center frequency of 2402MHz). The second BLE chip performs message scanning on a second scan channel (scan channel 38 with a center frequency of 2426 MHz). The third BLE chip performs message scanning on a third scan channel (scan channel 39 with a center frequency of 2480 MHz). The processor communicates with the first BLE chip, the second BLE chip, and the third BLE chip respectively. The scanning of the first BLE chip on the first scan channel, the scanning of the second BLE chip on the second scan channel, and the scanning of the third BLE chip on the third scan channel are performed simultaneously. Messages scanned by the respective BLE chips are transmitted to the processor through ETART interfaces, and then the processor filters and processes these messages. The processor may be a processor such as a CPET. Specifically, the first BLE chip, the second BLE chip, the third BLE chip, and the processor are integrated on a same printed circuit board.

In the present embodiment, the gateway uses three BLE chips, each of which scans a scan channel. Therefore, compared with the solution in the prior art in which a single BLE chip is used to poll three scan channels, the scan efficiency in this embodiment is doubled. In addition, three scan channels are scanned simultaneously, which increases the possibility of receiving messages and thus ensures the reliability of the entire BLE mesh network.

Furthermore, in a case where the gateway is integrated with a 2.4G WIFI module in addition to the processor and the three BLE chips, the gateway of this embodiment can solve the problem that the 2.4G WiFi module interferes with the scan channels of the BLE chips. Specifically, the BLE chips generally use scan channels 37, 38 and 39 for scanning. The relevant WIFI interference channels are channels 1, 3, 4, 5, 13 and 14, so the best solution is to use WIFI channels 2, 6, 7, 8, 9, 10, 11 and 12. 2.4G WIFI will only interfere with one to two of the first, second and third scan channels. Therefore, when the three BLE chips work simultaneously, the scanning of at least one BLE chip will not be affected by WIFI, which improves the reliability of data transmission. That is, when the 2.4G WIFI module works on a certain channel, it only affects a part of the scan channels of the BLE chips. For example, the WIFI channel 2412MHz only affects the first scan channel 37 (with a center frequency of 2402 MHz) and the second scan channel 38 (with a center frequency of 2426MHz) without interference to the third scan channel 39 (with a center frequency of 2480 MHz). The simultaneous scanning on three scan channels by three BLE chips can enhance the anti-interference ability and make the network more reliable.

In a preferred embodiment of the present disclosure, the lite-gateway has a configuration structure similar to the gateway. The lite-gateway also includes three BLE chips (a fourth BLE chip, a fifth BLE chip, and a sixth BLE chip). However, the lite-gateway does not have a processor and a WIFI module. The fourth BLE chip performs message scanning on a first scan channel. The fifth BLE chip performs message scanning on a second scan channel. The sixth BLE chip performs message scanning on a third scan channel. The fourth BLE chip, the fifth BLE chip, and the sixth BLE chip simultaneously perform message scanning on their respective scan channels. The fourth BLE chip, the fifth BLE chip, and the sixth BLE chip are integrated on a same printed circuit board.

The configuration principle of the lite-gateway is the same as that of the gateway, and will be omitted for brevity. The configuration of the lite-gateway in this embodiment can also double the scanning efficiency, which improves the possibility of receiving messages. Moreover, the lite-gateway can also enhance the anti-interference ability and make the network more reliable.

A sub-net configuration method for the BLE mesh network of Embodiment Two will be described below. Fig. 11 shows a schematic flowchart of a sub-net configuration method for the BLE mesh network in Fig. 7. As shown in Fig. 11, the sub-net configuration method mainly includes step S101 to step S104.

In step S 101 , gateways in the BLE mesh network each are allocated to different sub-nets.

Specifically, a gateway uniquely corresponds to a sub-net. Different gateways each are allocated to different sub-nets. Referring to an example in Fig. 13, a mesh network includes two gateways, namely, GW1 and GW2. In this case, gateway GW1 is allocated to a sub-net 201, and gateway GW2 is allocated to a sub-net 202. In step S102, each gateway in the BLE mesh network transmits, within a scope of the mesh network, sub-net information of a sub-net to which the gateway belongs. Here, sub-net information includes a sub-net identification code and a Time to Live value. Each time sub-net information is transmitted, the Time to Live value in the sub-net information will be decreased by 1.

Specifically, each gateway in the BLE mesh network periodically transmits, within a scope of the mesh network, sub-net information of a sub-net to which the gateway belongs. The way the gateway transmits its sub-net information may be to flood its sub-net information within a scope of the entire mesh network. Time to Live value in sub-net information is limited to prevent endless transmission of information.

The detailed description is still made with reference to the example in Lig. 13. Gateway GW1 outputs sub-net information associated with the sub-net to which gateway GW1 belongs. The sub-net information includes a sub-net identification code and a Time to Live value (hereinafter referred to as TTL value). The sub-net identification code uniquely corresponds to the sub-net and is the identity of the sub-net. The TTL value in the sub-net information output by gateway GW1 is a default value. In the example shown in Lig. 13, the default value of the TTL value is 3. The TTL value of the sub-net information output by gateway GW1 is 3. Each time the sub-net information is transmitted, the TTL value in the sub-net information will be decreased by 1. If a lite-gateway receives sub-net information whose TTL value is 3, the lite-gateway will decrease the TTL value of the sub-net information by 1 and then transmit it again to a subsequent lite-gateway that communicates with the lite-gateway. Each time a subsequent lite-gateway transmits the sub-net information, the TTL value of the sub-net information will be decreased by 1 until a certain lite-gateway receives the sub-net information whose TTL value is 0. If a lite-gateway receives the sub-net information whose TTL value is 0, the lite-gateway will directly discard the sub-net information whose TTL value is 0 and no longer transmit it.

In step S103, a lite-gateway receives sub-net information of each sub-net and determines a target sub-net according to the sub-net information. Specifically, a method for determining a target sub-net by a lite-gateway according to sub-net information is shown in Fig. 12. The method mainly includes step S1031 to step S1034.

In step S 1031, a lite-gateway compares TTL values in all received sub-net information.

In step S1032, the lite-gateway determines whether there is only one piece of sub-net information whose TTL value is the biggest among all the received sub-net information.

In step S1033, if it is determined that there is only one piece of sub-net information whose TTL value is the biggest among all the received sub-net information, a sub-net corresponding to sub-net information whose TTL value is the biggest is determined as a target sub-net.

In this step, a sub-net corresponding to the only sub-net information whose TTL value is the biggest is determined as a target sub-net.

In step S1034, if it is determined that there is more than one piece of sub-net information whose TTL value are all the biggest (namely, there are a plurality of pieces of sub-net information whose TTL value are all the biggest) among all the received sub-net information, a sub-net corresponding to sub-net information whose RSSI value is the biggest among the pieces of sub-net information whose TTL value are all the biggest is determined as a target sub-net.

In this step, if there are a plurality of biggest TTL values, a target sub-net is further determined based on RSSI values. That is, the RSSI values of the plurality of pieces of sub-net information whose TTL value are all the biggest are further compared to determine, as a target sub-net, the sub-net corresponding to the sub-net information whose RSSI value is biggest among the pieces of sub-net information.

In step S104, the lite-gateway joins in the determined target sub-net. Specifically, after the target sub-net is determined in the above manner, the lite-gateway joins in the target sub-net, so that the lite-gateway belongs to the target sub-net.

For each of separate lite-gateways (namely, a lite-gateway that has not yet been allocated to a certain sub-net), the method of the above step S101 to step S104 is applied to configure the separate lite-gateways into sub-nets so to complete sub-net configuration for the entire BLE mesh network. For a lite-gateway that cannot join in a certain sub-net using the above steps, the lite-gateway is set to belong to each of the sub-nets.

A process of lite-gateway LGW3 joining in a sub-net will be described with reference to Fig. 13. Gateway GW1 transmits to lite-gateway LGW3 sub-net information whose TTL value is 3. Gateway GW2 transmits to lite-gateway LGW3 sub-net information whose TTL value is 1 through two lite-gateways (the TTL value of the sub-net information transmitted by gateway GW2 is decreased by 1 each time the sub-net information passes through a lite-gateway, and after the relay of two lite-gateways, the TTL value turns from a default value of 3 to 1). Next, lite-gateway LGW3 compares the TTL values of the sub-net information from gateways GW1 and GW2, and takes as a target gateway gateway GW1 corresponding to the sub-net information whose TTL value is larger (i.e., 3). Then, lite-gateway LGW3 joins in the target sub-net 201 to which target gateway GW1 belongs.

A process of lite-gateway LGW4 joining in a sub-net will be described with reference to Fig. 13. Gateway GW1 transmits to lite-gateway LGW4 sub-net information whose TTL value is 2 through a lite-gateway. Gateway GW2 transmits to lite-gateway LGW4 sub-net information whose TTL value is 2 through a lite-gateway (the TTL value of the sub-net information transmitted by gateway GW2 is decreased by 1 each time the sub-net information passes through a lite-gateway, and after the relay of a lite-gateway, the TTL value is turned from a default value of 3 to 2). Next, lite-gateway LGW3 compares the TTL values of the sub-net information from gateways GW1 and GW2. In a case where the TTL values of the two pieces of sub-net information are identical (both being 2), gateway GW1 corresponding to the sub-net information whose RSSI value is bigger is taken as a target gateway. Then, lite-gateway LGW4 joins in the target sub-net 201 to which target gateway GW1 belongs.

According to the above method, a lite-gateway can use received sub-net information of each sub-net to select and join in a nearest sub-net. The setting of TTL value can limit times of transmission of sub-net information of each sub-net in the mesh network, which can reduce the network traffic.

In addition, there exist the problems in the prior art that, when edge nodes communicate with gateways, messages are transmitted in plain text and can be detected easily by third party, which causes a high risk of information leakage, and the entire network can also be attacked by hackers easily. In order to solve the above problems, preferably, sub-net information transmitted during the sub-net configuration process is encrypted, and then the encrypted sub-net information is transmitted within a scope of the mesh network. Upon reception of the encrypted sub-net information, lite-gateways decrypt the received encrypted sub-net information and determine target sub-nets according to the decrypted sub-net information. Specifically, sub-net information is encrypted with AES 128 algorithm.

The above sub-net configuration method can improve the security of transmission of sub-net information in the mesh network, which reduces the risk of leakage of sub-net information and the possibility of the entire network being attacked by hackers.

A message uploading method based on the BLE mesh network of Embodiment Two will be described below. Fig. 15 shows a schematic flowchart of a message uploading method based on the BLE mesh network of Fig. 7. As shown in Fig. 14, the message uploading method mainly includes step S201 to step S203.

In step S201, a Bluetooth tag broadcasts a message, the message including a message body, a message TTL value, and a message sequence number.

In step S202, a lite-gateway receives the message broadcast by the Bluetooth tag and floods the message in a sub-net to which the lite-gateway belongs, so as to transmit the message to a gateway in the sub-net.

In step S203, the gateway processes the received message and uploads the processed message to a cloud server.

A method for flooding a message in a sub-net to which a lite-gateway belongs involved in step S202 will be described in detail below with reference to Fig. 15.

A message broadcast by Bluetooth includes a message body, a message TTL value, and a message sequence number. The message body is the specific data to be uploaded to the cloud server. The message TTL value is similar to information TTL value involved in the sub-net configuration method, and is used to limit times of message transmission to prevent endless message transmission. The message sequence number is the identity of a message, each message having a unique message sequence number corresponding to the message. Here, the earlier a message output by a Bluetooth tag, the smaller the message sequence number of the message. Compared with a subsequently output message, an early output message is an old message.

Referring to Fig. 15, a message broadcast by Bluetooth tag TAG3 is first directly received by gateway GW1. In the sub-net 201, there are three communication paths associated with Bluetooth tag TAG4, namely, a first path of TAG4->LGW5->LGW6->LGW7, a second path of TAG4->LGW5->LGW8->GW1, and a third path of TAG4 ->LGW5->LGW6->LGW8->GW1.

In a message transmission process, for a lite-gateway for message relay, there are two processes involved. First, the lite-gateway performs an update operation of decreasing the TTL value in a received message by 1, and determines whether the TTL value in the message after the update operation is 0. If it is determined that the TTL value in the message after the update operation is 0, the lite-gateway discards the message after the update operation. If it is determined that the TTL value in the message after the update operation is greater than 0, it is further determined whether a message sequence number with a value greater than or equal to a value of the message sequence number in the message after the update operation has been stored locally. If it is determined that a message sequence number with a value greater than or equal to a value of the message sequence number in the message after the update operation has been stored locally, the lite-gateway discards the message after the update operation. If it is determined that a message sequence number with a value greater than or equal to a value of the message sequence number in the message after the update operation has not been stored locally, the lite-gateway locally stores the message sequence number in the message after the update operation, and transmits the message after the update operation to a lite-gateway or a gateway that communicates with the lite-gateway.

A message transmission process will be illustrated by taking lite-gateway LGW6 as an example. Upon reception of a message whose TTL value is 2 transmitted by lite-gateway LGW5, lite-gateway LGW6 first determines that the TTL value (which is 2) in the received message is greater than 0, and then decreases the TTL value of the message by 1, an updated TTL value being 1. Next, lite-gateway LGW6 determines whether a message sequence number with a value greater than or equal to a value of the message sequence number in the above message has been stored locally, namely, lite-gateway LGW6 determines whether a message that is a duplicate or old message with respect to said message has been stored locally. If it is determined that a message sequence number with a value greater than or equal to a value of the message sequence number in the above message has not been stored locally, lite-gateway LGW6 stores the message sequence number in the above message locally and transmits the updated message (whose TTL value is 1) to lite-gateway LGW7 and lite-gateway LGW8. Subsequently, lite-gateway LGW7 and lite-gateway LGW8 also transmit the message with the same procedure.

According to the above method, on the one hand, Bluetooth mesh networking utilizes a managed flood approach (i.e., broadcast flooding mechanism) for message transmission in a sub-net (namely, message TTL value is used to limit times of transmission of a message in a sub-net). Messages can only be transmitted within sub-nets, which reduces the network traffic. Hence, the above method is a simple and reliable form of message relay that is suited for low-power wireless mesh networks, especially those handling a significant amount of multicast traffic. This makes the above method an ideal approach for the strict reliability, scalability, and performance requirements of the commercial and industrial markets. On the other hand, according to the above method, the message sequence number can be used to suppress the situation where a message is repeatedly transmitted by the same lite-gateway and the situation where a lite-gateway transmits an old message after transmitting a new message. Thus, duplicate and old messages can be filtered out, which reduces duplicate traffic in the network and prevents malicious attacks.

In addition, there exist the problems in the prior art that, when edge nodes communicate with gateways, messages are transmitted in plain text and can be detected easily by third party, which causes a high risk of information leakage, and the entire network can also be attacked by hackers easily. In order to solve the above problems, preferably, a message transmitted during a message uploading process is encrypted, and then the encrypted message is flooded within a sub-net. Upon reception of the encrypted message transmitted by a Bluetooth tag or other lite-gateways, a lite-gateway decrypts the received encrypted message and determines that the message LLT value in the message after an update operation is greater than 0. If a message sequence number with a value greater than or equal to a value of the message sequence number in the message after the update operation has not been stored locally, the lite-gateway encrypts the message after the update operation and transmits the encrypted message to a lite-gateway or a gateway that communicates with the lite-gateway. Specifically, messages are encrypted with AES 128 algorithm.

The above method can improve the security of transmission of messages output by Bluetooth tags in sub-nets, which reduces the risk of message leakage and the possibility of the entire network being attacked by hackers.

A Bluetooth tag location determination method based on the BLE mesh network of Embodiment Two will be described below. Fig. 16 shows a schematic flowchart of a Bluetooth tag location determination method based on a BLE mesh network. As shown in Fig. 16, the Bluetooth tag location determination method mainly includes step S301 and step S302.

In step S301, a cloud server acquires RSSI values of messages broadcast by a Bluetooth tag and then received by at least three devices. Here, the at least three devices belong to the Bluetooth mesh network. Specifically, after a Bluetooth tag broadcasts messages, at least three devices in the BLE mesh network can directly receive the messages broadcast by the Bluetooth tag. Here, the expression “directly receive” means that the devices receive the messages broadcast by the Bluetooth tag without the relay of other devices, but directly scan the messages broadcast by the Bluetooth tag. The devices that directly receive the messages record in the messages RSSI values of the received messages. The devices may be lite-gateways or gateways. In a case where the devices are lite-gateways, the messages in which RSSI values are recorded are uploaded to the cloud server via the relay of gateways (or other lite-gateways and gateways). In a case where the devices are gateways, the messages in which RSSI values are recorded are directly uploaded to the cloud server.

In step S302, the cloud server determines location information of the Bluetooth tag according to the acquired RSSI values and preset location information of the at least three devices.

Specifically, first, for each of the at least three devices, a distance between the device and the Bluetooth tag is determined according to the RSSI value of the message from the Bluetooth tag received by the device. Then, the location information of the Bluetooth tag is determined according to the distance between each of the at least three devices and the Bluetooth tag and the preset location information of the at least three devices.

A distance between a device and the Bluetooth tag can be calculated by the following formula: d = 10 ^A ((abs(RSSI)-A) / (10 * n))

In the formula, d represents a distance between the device and the Bluetooth tag, RSSI represents a received signal strength indication value (negative value) when the device receives a message from the Bluetooth tag, A represents a signal strength when the Bluetooth tag and the device are 1 meter apart, and n represents an environmental attenuation factor. After acquiring the distance between each of the at least three devices and the Bluetooth tag, circles are drawn with the respective devices as centers. An intersection of the three circles is the location of the Bluetooth tag. According to the above method, the cloud server utilizes the RSSI values of the messages from the Bluetooth tag received by at least three devices in the Bluetooth mesh network in connection with the pre-stored location information of these devices to obtain the location information of the Bluetooth tag using geometric relationships. Hence, the above method provides a reliable Bluetooth tag locating method.

Although the embodiments disclosed in the present disclosure are as described above, the contents described are only the embodiments used to facilitate the understanding of the present disclosure, and are not intended to limit the present disclosure. Any person skilled in the technical field of the present disclosure can make any modifications and changes in the form and details of implementation without departing from the spirit and scope of the present disclosure. However, the scope of protection of the present disclosure shall still be subject to the scope as defined in the appended claims.