CN115428257A - Gateway for mesh network - Google Patents

Abstract

The invention discloses a gateway for a mesh network. The gateway uses a quadrangular shell, at least one antenna is respectively arranged at three corners in the shell, and for each of the three corners in the shell, an extension line of the antenna arranged at the corner in the length direction intersects with two sides forming the corner. According to the structure, in a space with limited antennas, through a reasonable arrangement mode, the signal isolation is improved, the mutual influence of signals among the antennas is reduced, and the signal receiving performance of the gateway is improved.

Description

Gateway for mesh network

Technical Field

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

Background

Conventionally, in the field of communication networks using Wi-Fi or bluetooth installed indoors, it is common for one transmitting device to communicate with one receiving device and to transmit information. Therefore, in order to grasp the positions of the devices and assets, transmission devices such as tags are mounted on the devices and assets, and reception devices such as gateways are provided in one-to-one correspondence with the transmitted electric waves.

The gateway generally includes a housing and a plurality of antennas provided in the housing, and can receive or transmit radio waves transmitted from or to an external device via the antennas.

However, in the conventional gateway, the distribution positions of the antennas in the housing often cause weak radio waves and packet loss in a certain direction, and even cause a signal receiving dead angle in a certain direction. This clearly seriously affects the signal reception performance of the gateway.

Therefore, a gateway for mesh network with high signal receiving performance is needed.

Disclosure of Invention

The invention aims to provide a gateway for a mesh network with high signal receiving performance.

The gateway for mesh network of the present invention uses a quadrangular housing,

at least one antenna is respectively arranged at three corners in the shell,

for each of the three corners in the case, an extension line of the antenna provided at the corner in the length direction intersects with two sides constituting the corner.

According to the structure, in a space with limited antennas, the signal isolation is improved through a reasonable arrangement mode, the mutual influence of signals among the antennas is reduced, and the signal receiving performance of the gateway is improved.

Preferably, the antenna is a planar inverted F antenna.

Here, the whole Planar Inverted F-shaped Antenna (PIFA) is shaped like an Inverted english letter F, so that its name is given. The basic structure of the planar inverted-F antenna is that a planar radiation unit is used as a radiator, the ground is used as a reflecting surface, and two Pin pins which are close to each other are arranged on the radiator and are respectively used for grounding and serving as feed points. The metal planar inverted-F antenna can change the feeding position and enable signal radiation to be concentrated in the front direction of the gateway, so that the signal receiving capacity of the gateway can be further improved.

Preferably, the antenna is disposed on a printed circuit board, and a height of the antenna with respect to the printed circuit board is greater than a height of other components disposed on the printed circuit board with respect to the printed circuit board.

According to the structure, the height of the antenna is larger than other parts on the printed circuit board, so that the bandwidth of the antenna can be widened, and the signal transmission capability of the gateway can be further improved.

Preferably, the antennas disposed at adjacent two of the three corners have their extensions in the length direction orthogonal to each other.

According to such a structure, since the antennas disposed at adjacent two of the three corners in the case are orthogonally disposed with respect to each other, the isolation between the orthogonally disposed antennas and the antennas is high. Therefore, in the relatively limited PCB space of the gateway, the isolation can be more than-15 dB through a reasonable arrangement mode, and the mutual influence of signals among the antennas is reduced.

Preferably, the gateway is mounted on the top of a wall with the bottom of the housing facing upwards.

According to the structure, the gateway is installed on the top of the wall in a ceiling-mounted mode, all areas of a room are covered as much as possible, signal radiation can be concentrated in the front direction of the gateway by using the metal plane inverted-F-shaped antenna, so that signal coverage in the room is good, signal radiation on the back side of the gateway is minimum, and mutual interference between the gateway and upstairs equipment is reduced.

Preferably, the gateway is capable of communicating with a light gateway having a plurality of bluetooth chips mounted thereon, and the light gateway has only a partial function of the gateway.

According to such a configuration, since a light gateway for relaying a message is added between the bluetooth tag and the gateway, it is possible to realize long-distance transmission of the message. In addition, the light gateway only has partial functions of the gateway, so the deployment cost of the light gateway is lower than that of the gateway, and the deployment cost of the mesh network can be effectively reduced.

Preferably, the gateway can communicate with a light gateway carrying at least three bluetooth chips.

Preferably, the gateway includes:

the first Bluetooth chip scans information on a first scanning channel;

the second Bluetooth chip performs message scanning on a second scanning channel;

a third bluetooth chip that performs message scanning on a third scanning channel; and

a processor which is respectively connected with the first Bluetooth chip, the second Bluetooth chip and the third Bluetooth chip in a communication way,

and the first Bluetooth chip, the second Bluetooth chip and the third Bluetooth chip simultaneously perform message scanning on respective scanning channels.

Preferably, the first bluetooth chip, the second bluetooth chip, and the third bluetooth chip of the gateway broadcast subnet information of the subnet in which the gateway is located on respective scanning channels.

Preferably, the light gateway includes:

the fourth Bluetooth chip scans the message on the first scanning channel;

a fifth bluetooth chip which performs message scanning on the second scanning channel; and

a sixth Bluetooth chip that performs message scanning on a third scanning channel,

and the fourth Bluetooth chip, the fifth Bluetooth chip and the sixth Bluetooth chip simultaneously perform message scanning on respective scanning channels.

According to the structure, the three Bluetooth chips of the gateway respectively scan the messages on the respective scanning channels, so that the scanning efficiency and the message receiving rate are improved, and the influence of the scanning processes on other wireless scanning channels on the scanning process of the gateway is effectively reduced. In a similar way, the three bluetooth chips that the light gateway possesses respectively carry out the scanning of message simultaneously on its respective scanning channel, when having improved scanning efficiency and message receiving rate, effectively alleviate the scanning process that carries on other wireless scanning channels and to the scanning process's of light gateway influence.

That is to say, the antennas arranged at different corners respectively work at different frequency points, so that the interference between signals can be further reduced, and the gateway and the light gateway are ensured to have higher receiving sensitivity.

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

According to the structure, the central frequencies of the scanning channels of the three Bluetooth chips of the gateway or the light gateway are set at 2402MHz, 2426MHz and 2480MHz, the WIFI module of the gateway comprises the 2.4G WIFI module and the 5G WIFI module, and the 2.4G WIFI module only influences one part of the scanning channels of the Bluetooth chips, so that the influence of the scanning process on the 2.4G wireless communication channel on the scanning process of the gateway or the light gateway can be effectively reduced.

Drawings

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

fig. 1 is a schematic diagram illustrating an internal structure of a gateway for a mesh network according to an embodiment of the present invention.

Fig. 2 shows a schematic view of the structure of an antenna arranged on a printed circuit board.

Fig. 3 is a schematic diagram illustrating isolation of antennas of a gateway for a mesh network according to an embodiment of the invention.

Fig. 4 is a schematic diagram illustrating a pattern synthesis of an antenna of a gateway for a mesh network according to an embodiment of the present invention.

Fig. 5 is a schematic diagram illustrating an installation of a gateway for a mesh network according to an embodiment of the invention.

Figure 6 shows a topology diagram of a prior art bluetooth low energy mesh network.

Fig. 7 shows a topology diagram of a bluetooth low energy mesh network according to a second embodiment of the invention.

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

Fig. 9 shows a schematic structural diagram of a gateway in the second embodiment of the present invention.

Fig. 10 shows a scanning policy diagram of a gateway in the second embodiment of the present invention.

Fig. 11 shows a flow diagram of a subnet configuration method for a bluetooth low energy mesh network.

Fig. 12 is a flowchart illustrating a method for determining a target subnet according to subnet information by a light gateway.

Fig. 13 is a diagram showing an example of a subnet configuration method of a bluetooth low energy mesh network.

Fig. 14 shows a flow diagram of a message uploading method based on a bluetooth low energy mesh network.

Fig. 15 is a diagram illustrating an example of a message uploading method based on a bluetooth low energy mesh network.

Figure 16 shows a flow diagram of a bluetooth tag location determination method based on a bluetooth low energy mesh network.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the following will describe in detail an implementation method of the present invention with reference to the accompanying drawings and embodiments, so that how to apply technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented.

In the conventional gateway, the distribution positions of the antennas in the housing usually cause weak radio waves and packet loss in a certain direction, and even cause signal receiving dead angles in a certain direction. This certainly seriously affects the signal reception performance of the gateway. To solve this problem, embodiments of the present invention provide a gateway for a mesh network with high signal reception performance.

Example one

Fig. 1 shows a schematic structural diagram of the interior of a housing 10 of a gateway 1 for a mesh network according to an embodiment of the present invention. Fig. 2 shows a schematic view of the structure of an antenna provided on a printed circuit board 30. As shown in fig. 1, a gateway 1 for a mesh network according to an embodiment of the present invention uses a housing 10 having a quadrangular shape. The gateway 1 includes at least three antennas housed in the housing 10. Referring to fig. 1, the gateway 1 is provided with three antennas, i.e., a first antenna 21, a second antenna 22, and a third antenna 23. The three antennas 21, 22, 23 are distributed at three corners within the housing 10. The housing 10 includes four corners therein, i.e., a first corner 11, a second corner 12, a third corner 13, and a fourth corner 14. The first antenna 21 is located at the first corner 11 in the housing 10, and an extension of the first antenna 21 in the length direction intersects with two sides constituting the first corner 11. The second antenna 22 is located at the second corner 12 in the housing 10, and the extension of the second antenna 22 in the length direction intersects with two sides constituting the second corner 12. The third antenna 23 is located at the third corner 13 inside the housing 10, and an extension of the third antenna 23 in the length direction intersects with two sides constituting the third corner 13.

Further, in the case where three or more antennas are accommodated inside the casing 10, two antennas are provided at least one of the three corners inside the casing 10. At this time, the two antennas may be disposed in parallel or non-parallel with each other as long as it is ensured that the extensions of the two antennas in the length direction both intersect with the two sides constituting the angle.

According to the structure, in a space with limited antennas, the signal isolation is improved through a reasonable arrangement mode, the mutual influence of signals among the antennas is reduced, and the signal receiving performance of the gateway 1 is improved.

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

According to such a structure, since the antennas disposed at adjacent two of the three corners in the housing 10 are orthogonally disposed with respect to each other, the isolation between the orthogonally disposed antennas and the antennas is high. The isolation data of the antennas are shown in fig. 3, and in the relatively limited PCB space of the gateway 1, the isolation can be more than-15 dB through a reasonable arrangement mode, so that the mutual influence of signals among the antennas is reduced. In addition, the receiving signal complementary covering capability of the antenna is better. Referring to the pattern combining case of XOY (Theta =90 °) for the three antennas shown in fig. 4, from the 2D pattern coverage point of view, the antennas of the gateway 1 can receive packets from different directions, and there is no case where it is particularly weak in a certain direction. For a direction with poor coverage of a certain antenna, the other two antennas can supplement coverage, that is, no direction has a receiving dead angle, so that the omnidirectional receiving performance is ensured, and the condition that packet loss is caused by weak signals possibly occurring in certain directions is reduced.

In a preferred embodiment of the present invention, referring to fig. 1 and 2, the antennas provided in the gateway 1 are all planar inverted F antennas. Here, the shape of the whole planar inverted F antenna is like an inverted english letter F, and is named. The basic structure of the planar inverted-F antenna is that a planar radiation unit is used as a radiator, the ground is used as a reflecting surface, and two Pin pins which are close to each other are arranged on the radiator and are respectively used for grounding and serving as feed points. Since the metal planar inverted F antenna can change the feeding position and concentrate the signal radiation in the direction of the front of the gateway 1, the signal receiving capability of the gateway 1 can be further improved.

In a preferred embodiment of the present invention, referring to fig. 1 and 2, the antennas provided in the gateway 1 are disposed on the printed circuit board 30. The height of each antenna relative to the printed circuit board 30 is greater than the height of other components disposed on the printed circuit board 30 relative to the printed circuit board 30. In particular, the height difference of the antenna from other components is greater than 10mm.

According to such a configuration, since the height of the antenna is larger than that of other components on the printed circuit board 30, the bandwidth of the antenna can be widened, and the signal transmission capability of the gateway 1 can be further improved.

In a preferred embodiment of the present invention, the gateway 1 is installed in a ceiling-mounted manner. Referring to fig. 5, the gateway 1 is installed on the top of the wall in such a manner that the bottom 15 of the housing 10 faces upward.

According to the structure, the gateway 1 is installed on the top of the wall in a ceiling-mounted mode, all areas of a room are covered as much as possible, signal radiation can be concentrated in the front direction of the gateway 1 by using the metal plane inverted-F antenna, signal coverage in the room is enabled to be good, meanwhile signal radiation on the back side of the gateway 1 is minimum, and mutual interference between the gateway 1 and upstairs equipment is reduced. In addition, the planar inverted F antenna used in the present embodiment can reduce signal interference more than the conventional printed antenna. Specifically, the radiation energy of the printed antenna is basically the same in the positive direction and the negative direction of the Z axis, so that the energy below the negative direction is less than that of the metal plane inverted F antenna, and the problem of mutual interference with the building can be caused if the radiation in the positive direction of the Z axis is stronger.

The gateway 1 described above may be used to form a bluetooth mesh network. The bluetooth mesh network, a subnet configuration method based on the bluetooth mesh network, a message uploading method, and a bluetooth tag position determining method will be described in detail below.

It should be noted that BLE (Bluetooth Low Energy) mesh network is taken as an example to describe the following embodiments in detail.

Example two

In conventional designs, BLE communications are peer-to-peer. The BLE tag or sensor node communicates directly with the gateway. As shown in fig. 6, the tags are respectively connected to the cloud server through two gateways. With this communication approach, due to the hardware limitations of BLE technology, messages cannot be transmitted over long distances, so the gateway must be deployed very close to the BLE tag to receive BLE messages sent by the BLE tag. In addition, the cost of the gateway is high, and the deployment density of the gateway is high, so that the deployment cost of the whole network is high.

In order to solve the technical problems in the prior art, embodiments of the present invention provide a bluetooth low energy mesh network that is capable of transmitting messages over long distances and has a low deployment cost.

The bluetooth low energy mesh network of the present embodiment is provided with a plurality of subnets. Each subnet is provided with one gateway and at least one light gateway. Here, the gateway acts as an access device, while the light gateway acts as a relay device. The light gateway has only partial functions of the gateway, and thus the deployment cost of the light gateway is lower than that of the gateway. The gateway is in communication connection with the cloud server. Each light gateway may be in communication with the gateway directly or via other light gateways. The messages output by the Bluetooth tag are relayed to the gateway through one or more light gateways, then the received messages are processed by the gateway and uploaded to the cloud server, and the uploaded messages are stored and analyzed by the cloud server.

Fig. 7 shows a topology diagram of a bluetooth low energy mesh network according to a second embodiment of the invention. Referring to fig. 7, the bluetooth low energy mesh network 200 is provided with a subnet 201, a subnet 202, and a subnet 203. The structure of the subnet is described below by taking the subnet 201 as an example. The subnetwork 201 comprises one gateway GW1 and two light gateways LGW1, LGW2. The TAG1 is communicatively connected to the gateway GW1 via the light gateway LGW 1. The TAG2 is communicatively connected to the gateway GW1 via a light gateway LGW2. Gateway GW1 is communicatively connected to cloud server 100. The light gateways belonging to the same subnet may be not communicatively connected to each other (e.g., the light gateway in subnet 201) or may be communicatively connected to each other (e.g., the light gateways in subnet 202 and subnet 203), which is not limited by the embodiment of the present invention.

In this embodiment, the light gateway only has partial functions of the gateway, such as a message receiving function, a message sending function, and a message filtering function. The function of the light gateway is not limited to this, and the light gateway may further include an assisted positioning function of the gateway, which is to perform assisted positioning based on a Received Signal Strength Indication value (RSSI).

By applying the bluetooth low energy mesh network of the embodiment, the light gateway for relaying the message is added between the bluetooth tag and the gateway, and the message can be transmitted to the gateway deployed outside the long distance after being relayed by the light gateway, so that the long distance transmission of the message can be realized. In addition, the light gateway only has partial functions of the gateway, so that the deployment cost of the light gateway is lower than that of the gateway, and the deployment cost of the Bluetooth low-power mesh network can be effectively reduced.

The embodiment of the invention is mainly used for establishing a simple, reliable and low-cost wireless transmission network, so as to solve the problem that the transmission distance of the Bluetooth low-power consumption mesh network is limited, and can assist in positioning the asset position. The bluetooth low energy mesh network of the embodiments of the present invention can implement many-to-many (M: M) device communication for creating a large-scale device network. The embodiment of the invention is suitable for being applied to building automation, asset management systems, sensor networks and other solutions of the Internet of things, and can realize large-scale, long-distance, reliable and safe communication among dozens, hundreds or even thousands of devices.

Fig. 8 shows a scanning strategy diagram of a gateway in the prior art. As shown in fig. 8, the gateway uses a single BLE chip to poll for three scanning channels. The BLE chip first performs a message scan on a first scan channel (scan channel 37, whose center frequency is 2402 MHz), then performs a message scan on a second scan channel (scan channel 38, whose center frequency is 2426 MHz), and then performs a message scan on a third scan channel (scan channel 39, whose center frequency is 2480 MHz). Next, the BLE chip repeatedly performs the above scanning process. When scanning the messages on the scanning channels, the time period of each scanning is determined by the scanning interval and the scanning window parameter.

However, when the gateway further includes the 2.4G WIFI module (the gateway of this embodiment includes the 2.4G WIFI module and the 5G WIFI module), the wireless scanning of the 2.4G WIFI module may interfere with one or two of the three scanning channels of the BLE chip, so as to reduce the reliability of data transmission.

In order to solve the above problems, embodiments of the present invention improve the internal configurations of the gateway and the light gateway. Fig. 9 shows a schematic structural diagram of a gateway according to an embodiment of the present invention, and fig. 10 shows a schematic scanning policy diagram of a gateway according to an embodiment of the present invention. In a preferred embodiment of the present invention, referring to fig. 9 and 10, the gateway includes a first bluetooth low energy chip, a second bluetooth low energy chip, a third bluetooth low energy chip, and a processor. The first bluetooth low energy chip performs a message scan on a first scan channel (scan channel 37, whose center frequency is 2402 MHz). The second bluetooth low energy chip performs a message scan on a second scan channel (scan channel 38, centered at 2426 MHz). The third bluetooth low energy chip performs a message scan on a third scan channel (scan channel 39, whose center frequency is 2480 MHz). The processor is in communication connection with the first Bluetooth low-power chip, the second Bluetooth low-power chip and the third Bluetooth low-power chip respectively. The scanning of the first Bluetooth low energy chip on the first scanning channel, the scanning of the second Bluetooth low energy chip on the second scanning channel and the scanning of the third Bluetooth low energy chip on the third scanning channel are carried out simultaneously. And the messages scanned by each Bluetooth low-power chip are transmitted to the processor through the UART interface, and the messages are filtered and processed by the processor. The processor may be a processor such as a CPU. In particular, the first bluetooth low energy chip, the second bluetooth low energy chip, the third bluetooth low energy chip and the processor are integrated on the same printed circuit board.

In this embodiment, since the gateway employs three bluetooth low energy chips, and each bluetooth low energy chip individually scans one scanning channel, compared with the prior art in which a single bluetooth low energy chip is used to poll three scanning channels, the scanning efficiency of this embodiment is increased by several times. In addition, because three scanning channels are scanned simultaneously, the possibility of receiving messages is increased, and the reliability of the whole Bluetooth low-power mesh network is ensured.

In addition, under the condition that the gateway integrates a 2.4 GWIFII module in addition to a processor and three Bluetooth low-power chips, the gateway of the embodiment can solve the problem that the 2.4G WIFI module interferes with a scanning channel of the Bluetooth low-power chip. Specifically, the channels used by the bluetooth low energy chip scan are typically scan channels 37, 38 and 39. The relevant WIFI interference channels are 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 1 to 2 of the first, second, and third scan channels. Therefore, under the condition that 3 bluetooth low energy chips work simultaneously, the scanning of at least one bluetooth low energy chip will not receive the influence of WIFI, and this has improved data transmission's reliability. That is, when the 2.4G WIFI module is operating on a certain channel, it only affects a portion of the scan channels of the bluetooth low energy chip. For example, the WIFI channel 2412MHz only affects the first scanning channel 37 (center frequency is 2402 MHz) and the second scanning channel 38 (center frequency is 2426 MHz), but the WIFI channel 2412MHz does not affect the third scanning channel 39 (center frequency is 2480 MHz). The three Bluetooth low-power chips are used for scanning 3 scanning channels simultaneously, so that the anti-interference capability can be improved, and the network is more reliable.

In a preferred embodiment of the present invention, the light gateway has a configuration structure similar to that of the gateway, and also has three bluetooth low energy chips (a fourth bluetooth low energy chip, a fifth bluetooth low energy chip, and a sixth bluetooth low energy chip). However, the light gateway does not have a processor and a WIFI module. And the fourth Bluetooth low-power chip scans the message on the first scanning channel. And the fifth Bluetooth low-power chip performs message scanning on the second scanning channel. And the sixth Bluetooth low-power chip performs message scanning on the third scanning channel. And the fourth Bluetooth low-power chip, the fifth Bluetooth low-power chip and the sixth Bluetooth low-power chip simultaneously scan messages on respective scanning channels. And the fourth Bluetooth low-power chip, the fifth Bluetooth low-power chip and the sixth Bluetooth low-power chip are integrated on the same printed circuit board.

The configuration principle of the light gateway is the same as that of the gateway, and repeated contents are not described herein again. The configuration of the light gateway in this embodiment can also increase the scanning efficiency by times, thereby improving the possibility of receiving messages, and on the other hand, the light gateway can also improve the anti-interference capability, so that the network is more reliable.

A subnet configuration method of the bluetooth low energy mesh network of the second embodiment is described below. Fig. 11 shows a flowchart of a subnet configuration method of the bluetooth low energy mesh network of fig. 7. As shown in fig. 11, the subnet configuration method mainly includes steps S101 to S104.

In step S101, each gateway in the bluetooth low energy mesh network is divided into different subnets.

Specifically, one gateway uniquely corresponds to one subnet. Different gateways are divided into different subnets. Referring to the example in fig. 13, the mesh network includes two gateways GW1 and GW2. In this case, gateway GW1 is divided into subnet 201, and gateway GW2 is divided into subnet 202.

In step S102, each gateway in the bluetooth low energy mesh network forwards subnet information of a subnet to which the gateway belongs within the mesh network. Here, the subnet information includes a subnet identification code and an information lifetime, and the information lifetime in the subnet information is reduced by 1 each time the subnet information is forwarded.

Specifically, each gateway in the bluetooth low energy mesh network periodically forwards subnet information of the subnet to which the gateway belongs within the mesh network range. The gateway may forward the subnet information in such a way that the subnet information is flooded throughout the mesh network. In order to prevent the information from being forwarded endlessly, the information lifetime in the subnet information is limited.

The detailed description is still made with reference to the example in fig. 13. The gateway GW1 outputs subnet information associated with a subnet to which the gateway GW1 belongs. The subnet information includes a subnet identification code and an information lifetime (hereinafter referred to as TTL value, time to Live value). The subnet identification code is uniquely corresponding to the subnet and is the identity of the subnet. The information lifetime in the subnet information output by gateway GW1 is a default value. In the example shown in fig. 13, the default value of TTL value is 3. The TTL value of the subnet information output by gateway GW1 is 3. The lifetime of the information in the subnet information is reduced by 1 every time the subnet information is forwarded. And after receiving the subnet information with the TTL value of 3, the light gateway continuously forwards the subnet information to a subsequent light gateway in communication connection with the light gateway after subtracting 1 from the TTL value of the subnet information. And when the subnet information is forwarded by the subsequent light gateway once, the TTL of the subnet information is also reduced by 1 by itself until a certain light gateway receives the subnet information with the TTL value of 0. When receiving the subnet information with TTL value of 0, a certain light gateway directly discards the subnet information with TTL value of 0 without forwarding outwards.

In step S103, the light gateway receives subnet information of each subnet, and determines a target subnet according to the subnet information.

Specifically, a method for the light gateway to determine the target subnet according to the subnet information is shown in fig. 12. The method mainly includes steps S1031 to S1034.

In step S1031, the light gateway compares the information lifetime in all the received subnet information.

In step S1032, the light gateway determines whether only one subnet information having the largest information lifetime exists among all the received subnet information.

In step S1033, when it is determined that only one subnet information having the largest information lifetime exists in all the received subnet information, the subnet corresponding to the subnet information having the largest information lifetime is determined as the target subnet.

In this step, the subnet corresponding to only one subnet information having the largest information lifetime is determined as the target subnet.

In step S1034, when it is determined that there is not only one subnet information having the largest information lifetime (i.e., there are a plurality of subnet information having the largest information lifetime), among all the received subnet information, the subnet corresponding to the subnet information having the largest received signal strength indication value among the subnet information having the largest information lifetime is determined as the target subnet.

In this step, when a plurality of information survival times are aligned to be the maximum, the target subnet is determined based on the received signal strength indication value. That is, the received signal strength indication values of the plurality of pieces of subnet information having the largest information lifetime in parallel are compared, and the subnet corresponding to the subnet information having the largest received signal strength indication value among the plurality of pieces of subnet information is determined as the target subnet.

In step S104, the light gateway joins the determined target subnet.

Specifically, after the target subnet is determined in the above manner, the light gateway is added to the target subnet so as to be subordinate to the target subnet.

The method of steps S101 to S104 above is applied to each individual light gateway (i.e. light gateway not belonging to a certain subnet yet) to configure these individual light gateways into the subnet, thereby completing the subnet configuration of the entire bluetooth low energy mesh network. For a light gateway that cannot join a certain subnet using the above steps, it is set that the light gateway belongs to each subnet.

The process of joining the subnet by the light gateway LGW3 is explained with reference to fig. 13. The gateway GW1 transmits subnet information with TTL as default value 3 to the light gateway LGW 3. The gateway GW2 transmits the subnet information with TTL of 1 to the light gateway LGW3 through the two light gateways (the TTL value of the subnet information transmitted by the gateway GW2 is reduced by 1 for each light gateway, and after relaying through the two light gateways, the TTL value is changed from the default value of 3 to 1). Next, the light gateway LGW3 compares TTL values of the subnet information from the gateways GW1 and GW2, and takes the gateway GW1 corresponding to the subnet information having a larger TTL value (i.e., 3) as the target gateway. Then, the light gateway LGW3 joins the target subnet 201 to which the target gateway GW1 belongs.

A procedure for the light gateway LGW4 joining the subnet is explained with reference to fig. 13. The gateway GW1 transmits the subnet information with TTL of 2 to the light gateway LGW4 through one light gateway. The gateway GW2 transmits the subnet information with TTL of 2 to the light gateway LGW4 through one light gateway (the TTL value of the subnet information transmitted by the gateway GW2 is reduced by 1 for each light gateway, and is changed from the default value of 3 to 2 after relaying through one light gateway). Next, the light gateway LGW3 compares TTL values of the subnet information from the gateways GW1 and GW2, and when the TTL values of the two subnet information are compared to be the same (both are 2), the gateway GW1 corresponding to the subnet information having a large received signal strength indication value is set as the target gateway. Then, the light gateway LGW4 joins the target subnet 201 to which the target gateway GW1 belongs.

According to the method, the light gateway can select and join the subnet closest to the light gateway by using the received subnet information of each subnet. The setting of the information survival time can limit the forwarding times of the subnet information of each subnet in the mesh network, and can reduce the network flow.

In addition, in order to solve the problems that in the prior art, when an edge node communicates with a gateway, a message sent in a plain text format can be easily detected by a third party, so that the risk of information leakage is high, and the whole network is easily attacked by a hacker, preferably, subnet information transmitted in a subnet configuration process is encrypted, then the encrypted subnet information is forwarded within the range of a mesh network, and after receiving the encrypted subnet information, the light gateway decrypts the received encrypted subnet information and determines a target subnet according to the decrypted subnet information. Specifically, the subnet information is encrypted using the AES128 algorithm.

The subnet configuration method can improve the security of subnet information transmission in the mesh network, thereby reducing the leakage risk of subnet information and the possibility of hacking of the whole network.

A message uploading method of the bluetooth low energy mesh network according to the second embodiment is described below. Fig. 15 shows a flowchart of a message uploading method based on the bluetooth low energy mesh network of fig. 7. As shown in fig. 14, the message uploading method mainly includes steps S201 to S203.

In step S201, the bluetooth tag broadcasts a message, which includes a message body, a message lifetime, and a message sequence number.

In step S202, the light gateway receives the message broadcasted by the bluetooth tag, and performs flooding transmission on the message in the subnet to which the light gateway belongs, so as to forward the message to the gateway in the subnet.

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

The method for performing flooding transmission on a message in the subnet to which the light gateway belongs in step S202 is described in detail below with reference to fig. 15.

The message broadcast by bluetooth comprises a message body, a message lifetime and a message sequence number. The message text is specific data to be uploaded to the cloud server. The message lifetime is similar to the information lifetime involved in the subnet configuration method, and is used for limiting the transmission times of the message so as to prevent the endless forwarding of the message. The message sequence number is an identification of the message, and each message has a message sequence number uniquely corresponding to it. Here, the earlier the time of the message output by the bluetooth tag is, the smaller the message sequence number of the message is, and the earlier the message output is an old message compared to the message output subsequently.

Referring to fig. 15, the message broadcasted by the bluetooth TAG3 is first received directly by the gateway GW1. In the subnet 201, there are three communication paths associated with the bluetooth TAG 4: route one, TAG3- > LGW5- > LGW6- > LGW7; a second route, TAG3- > LGW5- > LGW8- > GW1; and the third route is TAG3- > LGW5- > LGW6- > LGW8- > GW1.

There are two processes involved by the light gateway for relaying messages during message transmission. Firstly, the light gateway executes an updating operation of subtracting 1 from the message lifetime in the received message, and judges whether the message lifetime in the message after the updating operation is 0 or not, if the message lifetime in the message after the updating operation is judged to be 0, the message after the updating operation is discarded, and if the message lifetime in the message after the updating operation is judged to be more than 0, whether the message sequence number with the value more than the message sequence number in the message after the updating operation is stored locally or not is further judged. And under the condition that the message sequence number of the updated message of which the value is not stored locally is judged, the message sequence number in the updated message is stored locally and the updated message is forwarded to a light gateway or a gateway which is in communication connection with the light gateway.

The forwarding process of the message is described by taking the light gateway LGW6 as an example. After receiving the message with the TTL value of 2 forwarded by the light gateway LGW5, the light gateway LGW6 first determines that the TTL value (2) in the received message is greater than 0, and then the light gateway LGW6 subtracts 1 from the TTL value of the message, and the updated TTL value is 1. Next, the light gateway LGW6 determines whether a message sequence number whose value is greater than or equal to the message sequence number in the message is stored locally, that is, the light gateway LGW6 determines whether a message which is a duplicate message or an old message with respect to the message is stored locally, and the light gateway LGW6 stores the message sequence number in the message locally and forwards the updated message (with a TTL value of 1) to the light gateway LGW7 and the light gateway LGW8 when determining that the message sequence number whose value is greater than or equal to the message sequence number in the message is not stored locally. Subsequently, the light gateway LGW7 and the light gateway LGW8 also forward the message using the same flow.

According to the above method, in one aspect, a bluetooth low energy mesh network utilizes a flooding method (i.e., a flooding mechanism) in which message transmission is managed (i.e., message lifetime is utilized to limit the number of times a message is forwarded in a subnet) for message propagation in a subnet. Messages can only be forwarded within the subnet range, thus reducing network traffic. It can be seen that the above method is a simple and reliable form of message relaying suitable for low power wireless mesh networks, particularly those handling large amounts of multicast traffic. This makes the above approach ideal for applications in the business and industrial markets with stringent reliability, scalability and performance requirements. On the other hand, the method can inhibit the situation that the message is repeatedly forwarded by the same light gateway and the situation that the light gateway forwards the old message after forwarding the new message through the message sequence number, so that the repeated message and the old message can be filtered, thereby reducing the repeated service in the network and preventing malicious attack.

In addition, in order to solve the problems that in the prior art, when an edge node communicates with a gateway, a message sent in a plain text format can be easily detected by a third party, so that the risk of information leakage is high, and the whole network is easily attacked by a hacker, preferably, the message transmitted in the message uploading process is encrypted, then the encrypted message is subjected to flood transmission in a subnet range, and after receiving the encrypted message transmitted by a bluetooth tag or other light gateways, the light gateway decrypts the received encrypted message, judges that the message survival time in the updated message is greater than 0, and encrypts the updated message under the condition that the message serial number whose value is greater than or equal to the message serial number in the updated message is not stored locally, and forwards the encrypted message to the light gateway or the gateway in communication connection with the light gateway. In particular, the AES128 algorithm is used to encrypt the message.

The method can improve the safety of the transmission of the message output by the Bluetooth tag in the subnet, thereby reducing the leakage risk of the message and the possibility that the whole network is attacked by hackers.

A bluetooth tag location determination method based on the bluetooth low energy mesh network of the second embodiment is described below. Figure 16 shows a flow diagram of a bluetooth tag location determination method based on a bluetooth low energy mesh network. As shown in fig. 16, the bluetooth tag position determination method mainly includes step S301 and step S302.

In step S301, the cloud server obtains received signal strength indication values of messages broadcast by the at least three devices receiving the bluetooth tag. Here, at least three devices are affiliated with the bluetooth mesh network.

Specifically, after the bluetooth tag broadcasts the message, at least three devices in the bluetooth low energy mesh network can directly receive the message broadcasted by the bluetooth tag. Here, the direct reception means that the device does not receive the message broadcasted by the bluetooth tag via the relay of the other device, but directly scans for the message broadcasted by the bluetooth tag. Each device that directly receives a message records in the message the received signal strength indication value of the received message. The device may be a light gateway or a gateway. In the case where the device is a light gateway, the message recorded with the received signal strength indication value is uploaded to the cloud server via a relay of the gateway (or other light gateways and gateways). And under the condition that the equipment is a gateway, directly uploading the message recorded with the received signal strength indicating value to a cloud server.

In step S302, the cloud server determines location information of the bluetooth tag according to the obtained received signal strength indication value and preset location information of at least three devices.

Specifically, first, for each of at least three devices, the distance between the device and the bluetooth tag is determined from the received signal strength indication value of the message from the bluetooth tag received by the device. Then, the position 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 position information of the at least three devices.

The distance between the device and the bluetooth tag may be calculated by:

d＝10^((abs(RSSI)-A)/(10*n))

where d denotes a distance between the device and the bluetooth tag, RSSI denotes a received signal strength indication value (negative value) when the device receives a message from the bluetooth tag, a denotes a signal strength when the bluetooth tag and the device are separated by 1 meter, and n denotes an environmental attenuation factor.

After the distance between each device of the at least three devices and the Bluetooth tag is obtained, a circle is drawn by taking each device as the center, and the intersection of the three circles is the position of the Bluetooth tag.

According to the method, the cloud server obtains the position information of the Bluetooth tag by using the geometrical relationship by using the received signal strength indicating values of the messages from the Bluetooth tag, which are received by at least three devices in the Bluetooth mesh network, and combining the position information of the devices which is stored in advance. Therefore, the method provides a reliable positioning method of the Bluetooth tag.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. A gateway for a mesh network using a quadrangular housing,

at least one antenna is respectively arranged at three corners in the shell,

for each of the three corners in the case, an extension line of the antenna provided at the corner in the length direction intersects with two sides constituting the corner.

2. The gateway of claim 1, wherein the antenna is a planar inverted-F antenna.

3. The gateway of claim 2, wherein the antenna is disposed on a printed circuit board, and wherein a height of the antenna relative to the printed circuit board is greater than a height of other components disposed on the printed circuit board relative to the printed circuit board.

4. The gateway according to any one of claims 1 to 3, wherein the antennas provided at adjacent two of the three corners have their extensions in the length direction orthogonal to each other.

5. The gateway according to any one of claims 1 to 3, wherein the gateway is installed on top of a wall with the bottom of the housing facing upward.

6. The gateway according to any one of claims 1 to 3, wherein the gateway is capable of communicating with a light gateway having a plurality of Bluetooth chips mounted thereon, and the light gateway has only a partial function of the gateway.

7. The gateway of claim 6, wherein the gateway is capable of communicating with a light gateway carrying at least three Bluetooth chips.

8. The gateway according to claim 7, wherein the gateway comprises:

the first Bluetooth chip scans information on a first scanning channel;

the second Bluetooth chip performs message scanning on a second scanning channel;

a third bluetooth chip that performs message scanning on a third scanning channel; and

a processor which is respectively connected with the first Bluetooth chip, the second Bluetooth chip and the third Bluetooth chip in a communication way,

and the first Bluetooth chip, the second Bluetooth chip and the third Bluetooth chip simultaneously perform message scanning on respective scanning channels.

9. The gateway for a mesh network according to claim 7, wherein the light gateway comprises:

the fourth Bluetooth chip scans the message on the first scanning channel;

a fifth bluetooth chip which performs message scanning on the second scanning channel; and

a sixth Bluetooth chip that performs a message scan on a third scan channel,

and the fourth Bluetooth chip, the fifth Bluetooth chip and the sixth Bluetooth chip simultaneously perform message scanning on respective scanning channels.

10. The gateway according to claim 8 or 9,

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

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