CN111565378A - LoRa communication method and LoRa communication system - Google Patents
LoRa communication method and LoRa communication system Download PDFInfo
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- H04W4/80—Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
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- H04W—WIRELESS COMMUNICATION NETWORKS
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- H04W72/12—Wireless traffic scheduling
- H04W72/1263—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
- H04W72/1268—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows of uplink data flows
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- H04W72/53—Allocation or scheduling criteria for wireless resources based on regulatory allocation policies
Abstract
The invention discloses a LoRa communication method and a LoRa communication system, wherein the method comprises the following steps: entering a downlink effective time interval, and in the downlink effective time interval: the service node works in a sending state and sends downlink data to a downlink channel; a plurality of terminal nodes work in a receiving state and receive downlink data from a downlink channel; entering an uplink effective time interval after the downlink effective time interval is ended, and in the uplink effective time interval: the plurality of terminal nodes work in a sending state and send various types of data to corresponding various types of uplink channels; the service node works in a receiving state and receives corresponding various types of uplink data from various types of uplink channels; entering the downlink effective time interval again after the uplink effective time interval is ended, so that the downlink data and the uplink data do not conflict; and the collision between uplink data can be reduced, and in conclusion, the invention can achieve the effects of improving the system throughput and reducing the data collision.
Description
Technical Field
The present invention relates to the field of communications, and in particular, to an LoRa communication method and an LoRa communication system.
Background
The LoRa is a long-distance, low-power consumption, wireless communication technology suitable for the internet of things, and referring to fig. 1, devices in the LoRa communication system mainly include a terminal, a gateway, and a server. The LoRa technology is mainly used for communication between a gateway and a terminal, and a star topology is mostly adopted between the gateway and the terminal. At present, the main chip supporting the LoRa adopts a half-duplex mode, that is, neither the gateway nor the terminal can perform the sending and receiving operations at the same time.
At present, LoRa is mainly applied to services such as water meters and the like, the data volume of the services is small, the real-time requirement is generally low, and the transmission data mainly utilizes an Aloha (namely, data is randomly generated and randomly sent), so that the management and working mode of the system are simpler, but the throughput of the system is lower, and the data collision probability is higher.
Disclosure of Invention
The present invention is directed to provide a LoRa communication method and a LoRa communication system, which solve the problem of high data collision probability in the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows: an LoRa communication method is constructed, and is suitable for an LoRa communication system comprising a service node and a plurality of terminal nodes, and the method comprises the following steps:
entering a downlink effective time interval, and in the downlink effective time interval: the service node works in a sending state and sends downlink data to a downlink channel; the plurality of terminal nodes work in a receiving state and receive the downlink data from the downlink channel;
entering an uplink effective time interval after the downlink effective time interval is ended, and in the uplink effective time interval: the plurality of terminal nodes work in a sending state and send various types of data to corresponding various types of uplink channels; the service node works in a receiving state and receives corresponding various types of uplink data from various types of uplink channels;
and entering the downlink effective time interval again after the uplink effective time interval is ended.
Preferably, the method further comprises:
and entering a waiting time interval after the uplink effective time interval is finished, wherein the service node and the plurality of terminal nodes all work in a data processing state in the waiting time interval, and entering the downlink effective time interval after the waiting time interval is finished.
Preferably, before entering the downlink validity time interval for the first time, the service node performs the following steps:
determining the time slot lengths of downlink data and various types of uplink data;
determining downlink communication parameters, including: determining the time length of the downlink effective time interval according to the time slot length of the downlink data;
determining uplink communication parameters, including: and determining classification results of a plurality of preset uplink channels in the system, the time length of the uplink effective time interval and the time slot allocation results of part types of uplink data with relatively low real-time requirements according to the type of the uplink data, the time slot length of various types of uplink data and the number of preset terminal nodes related to the specific application requirements of the system.
Preferably, the method further comprises:
and when the service node works in a data processing state in the waiting time interval, determining the number of the online terminal nodes, and re-determining the uplink communication parameters when the number of the online terminal nodes changes in a staged manner.
Preferably, the type of uplink data related to the specific application requirement of the system includes network access data, random data, and periodic data, and the determining the uplink communication parameter specifically includes:
performing type division on the plurality of uplink channels: dividing the plurality of uplink channels into three types of network access channels, random channels and periodic channels;
determining the time length of the uplink effective time interval to meet the uplink requirement of the random data according to the number of preset terminal nodes, the time slot length of the random data and the number of random channels;
verifying whether the number of the periodic channels meets the uplink requirement of the periodic data or not according to the number of preset terminal nodes, the time slot length of the periodic data and the time length of the uplink effective time interval, and if the number of the periodic channels does not meet the uplink requirement of the periodic data, directly re-determining the time length of the uplink effective time interval or re-determining the time length of the uplink effective time interval after updating the numbers of the periodic channels and the random channels until the verification is passed;
and allocating specific periodic channels and periodic time slots for the periodic data, and allocating specific random channels and random time slots for the random data.
Preferably, the determining the uplink communication parameter further includes:
if the type of uplink data related to the specific application requirements of the system also includes emergency data, the type of the emergency channel needs to be divided when the types of the plurality of uplink channels are divided;
after the time length of the uplink effective time interval is determined, whether the number of the emergency channels meets the uplink requirement of the emergency data needs to be verified according to the time slot length of the emergency data and the time length of the uplink effective time interval, if the time slot length of the uplink effective time interval does not meet the uplink requirement of the emergency data, the time length of the uplink effective time interval is directly determined again, or the time length of the uplink effective time interval is determined again after the numbers of the emergency channels and the random channels are updated until the time length of the uplink effective time interval passes the verification.
Preferably, the determining the uplink communication parameter further includes:
if a relay node exists in the system, when the types of the plurality of uplink channels are divided, a reserved relay channel is also divided when the types of the plurality of uplink channels are divided, wherein the reserved relay channel is specially used for transmitting data sent by the relay node.
Preferably, the uplink requirement of the periodic data is:
the sending period of the periodic data is integral multiple of a small period, and the small period consists of a downlink effective time interval, an uplink effective time interval and a waiting time interval;
and dividing all the uplink effective time intervals of K continuous small periods into a plurality of periodic time slots according to the time slot length of the periodic data, wherein the periodic channel and the periodic time slot which are distributed to each terminal node are not identical to the periodic channel and the periodic time slot of other terminal nodes, K is a positive integer and is determined by the ratio of the transmission period of the periodic data to the small period.
Preferably, the uplink requirement of the random data is: dividing the uplink effective time interval into a plurality of random time slots according to the time slot length of the random data, grouping all the terminal nodes in a mode that a plurality of terminal nodes are in a group, wherein the number of the terminal nodes in each group meets the probability standard of random data transmission, and the random channels and the random time slots distributed to the terminal nodes in each group are not identical to the random channels and the random time slots of other terminal nodes.
Preferably, the types of uplink data related to the specific application requirements of the system include network access data, emergency data, random data, and periodic data, and the types of the uplink channels include a network access channel, an emergency channel, a random channel, and a periodic channel;
the uplink mode of the network access data is as follows: randomly generating random signals and sending the random signals to the network access channel;
the uplink mode of the emergency data is as follows: randomly generating a random signal to be sent to the emergency channel;
the uplink mode of the periodic data is as follows: sending the periodic data of each terminal node to an allocated periodic channel in an allocated periodic time slot;
the uplink mode of the random data is as follows: and sending the random data of each terminal node to the allocated random channel in the allocated random time slot.
The invention also discloses an LoRa communication system, which comprises a service node and a plurality of terminal nodes, wherein the LoRa communication system realizes communication based on the method.
The LoRa communication method and the LoRa communication system have the following beneficial effects: in the invention, a downlink effective time interval and an uplink effective time interval are set, wherein the downlink effective time interval only contains downlink data, and the uplink effective time interval only contains uplink data, so that the downlink data and the uplink data do not conflict; in addition, for the uplink data, the invention sends various types of data to corresponding various types of uplink channels, that is, different uplink channels are allocated to the uplink data, so that the conflict between the uplink data can be reduced, and in summary, the invention can achieve the effects of improving the system throughput and reducing the data collision.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts:
fig. 1 is a schematic structural diagram of a LoRa communication system;
FIG. 2 is a flow chart of a communication method of the present invention;
FIG. 3 is a diagram of channel allocation and time allocation in one embodiment;
FIG. 4 is a schematic diagram of channel allocation and time allocation in another embodiment;
fig. 5 is a schematic diagram of channel allocation and time allocation in yet another embodiment.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Exemplary embodiments of the invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
The general idea of the invention is as follows: in the LoRa communication system, the downlink effective time interval is entered after the downlink effective time interval is finished, the downlink effective time interval is entered again after the uplink effective time interval is finished, the circulation is equivalent to entering the downlink effective time interval and the uplink effective time interval in turn, if the time between the entry points of two adjacent downlink effective time intervals is taken as a small period, the repetition is equivalent to the repetition of the set small period, in each small period, the data downlink is specially carried out in the downlink effective time interval, the data uplink is specially carried out in the uplink effective time interval, and the downlink data and the uplink data can not conflict. In addition, for the uplink situation, the terminal node sends various types of data to corresponding various types of uplink channels, that is, different uplink channels are allocated to the uplink data, so that the collision between the uplink data can be reduced, and finally the effects of improving the system throughput and reducing the data collision can be achieved.
In order to better understand the technical solutions, the technical solutions will be described in detail below with reference to the drawings and the specific embodiments of the specification, and it should be understood that the embodiments and specific features of the embodiments of the present invention are detailed descriptions of the technical solutions of the present application, and are not limited to the technical solutions of the present application, and the technical features of the embodiments and examples of the present invention may be combined with each other without conflict.
Referring to fig. 2, there is a flow chart of the communication method of the present invention. The present invention is applicable to an LoRa communication system including a service node and a plurality of terminal nodes, and it should be noted that, although the gateway is not mentioned in the following, the service node and the plurality of terminal nodes actually communicate through the gateway, and specifically, refer to fig. 1.
The communication method of the present invention includes:
s101, entering a downlink effective time interval, and in the downlink effective time interval: the service node works in a sending state and sends downlink data to a downlink channel; the plurality of terminal nodes work in a receiving state and receive the downlink data from the downlink channel;
s102, entering an uplink effective time interval after the downlink effective time interval is ended, and in the uplink effective time interval: the plurality of terminal nodes work in a sending state and send various types of data to corresponding various types of uplink channels; the service node works in a receiving state and receives corresponding various types of uplink data from various types of uplink channels;
the LoRa communication system may be applied to various practical applications, which may differ from each other in terms of the type of uplink data involved, and in a specific application, the type of uplink data required may also differ from each other in terms of different requirements, but generally, the type of uplink data generally includes several types of network access data, urgent data, random data, and periodic data. The network access data represents data which is accessed to the network for the first time or accessed to the network again after a period of time; emergency data, also called SOS data, represents data that is randomly generated and has high real-time requirements; random data representing data that is randomly generated and has low real-time requirements; and the periodic data represents data which needs to be transmitted by each terminal for a fixed time. These above categories of data may not exist according to the practical application of the LoRa communication system, for example: real-time is not required for practical applications, and urgent data does not exist.
In the present invention, each type of uplink data is allocated with a corresponding type of dedicated uplink channel, for example, the types of uplink channels respectively corresponding to network access data, emergency data, random data, and periodic data are: network access channel, emergency channel, random channel, periodic channel.
Preferably, in the present invention: the uplink mode of the network access data can be a slot-Aloha mode or an Aloha mode. In the Aloha scheme, data is transmitted completely randomly in time, while Slot Aloha divides time into time slices, and data can be transmitted only at a specified starting point. The performance difference of slot-Aloha and Aloha is as follows: the Aloha time delay is smaller (under the same condition), but the system data throughput of slot _ Aloha is (theoretically) 2 times that of Aloha, so that it is simpler if Aloha is used to directly send network data, and if slot _ Aloha is used, a synchronization starting point is needed. The uplink mode of the emergency data is a slot-Aloha mode or an Aloha mode. The uplink mode of the periodic data is as follows: and sending the periodic data of each terminal node to an allocated periodic channel in an allocated periodic time slot. The uplink mode of the random data is as follows: and sending the random data of each terminal node to the allocated random channel in the allocated random time slot. Here, the time slot means a time slot in practice.
And S103, entering a waiting time interval after the uplink effective time interval is finished, wherein the service node and the plurality of terminal nodes work in a data processing state in the waiting time interval, and entering the downlink effective time interval after the waiting time interval is finished.
Theoretically, after a time interval is finished, the horse can enter the next time interval, or the horse can enter the next time interval after waiting for a certain time. Referring to fig. 3-5, the horizontal axis represents channels and the vertical axis represents time, Td represents a downlink active time interval, Tu represents an uplink active time interval, and Tw represents a latency interval. The Td, Tu and Tw form a small period Ta together, and the whole system, no matter the service node or the terminal node, synchronously and repeatedly enters the small period Ta, in other words, the whole communication process is formed by splicing a plurality of small periods Ta.
The above steps S101 to S103 relate to various communication parameters, such as: the length of each time interval, the classification result of the uplink channel, and the time slot allocation result of the uplink data of the partial type (such as random data and periodic data) with relatively low real-time requirement. These communication parameters may be predetermined at the time of initialization of the serving node, and for this purpose, the method of the present invention further includes: before entering the downlink validity time interval for the first time, i.e. before entering step S101, the service node performs the following steps S100a-S100 c.
And S100a, determining the time slot lengths of the downlink data and various types of uplink data.
Specifically, the time slot lengths of the downlink data and the various types of uplink data can be calculated according to the data lengths of the downlink data and the various types of uplink data which are input in advance and the adopted Spreading Factors (SF).
Taking downlink data as an example, the data length of the downlink data and the adopted SF need to be input in advance, the service node can directly call the existing widget, and the widget can directly calculate the theoretical transmission time of the gateway chip based on the data length and the adopted SF. After the theoretical transmission time is obtained by calculation, the time slot length of the gateway downlink, that is, the time slot length of the downlink data, can be obtained by expanding a certain multiple (for example, 1.2 times) on the basis of the theoretical transmission time. The method for determining the slot lengths of the periodic data, the random data and the emergency data is the same, and will not be described herein again.
S100b, determining downlink communication parameters, including: and determining the time length of the downlink effective time interval according to the time slot length of the downlink data. In the invention, the time length of the downlink effective time interval is equal to the time slot length of downlink data.
S100c, determining uplink communication parameters, including: and determining classification results of a plurality of preset uplink channels in the system, the time length of the uplink effective time interval and the time slot allocation results of part types of uplink data with relatively low real-time requirements according to the type of the uplink data, the time slot length of various types of uplink data and the number of preset terminal nodes related to the specific application requirements of the system.
More specifically, the determining the uplink communication parameter in step S100c specifically includes:
and S100c1, performing type division on the plurality of uplink channels.
Referring to fig. 3, in a specific embodiment, the types of uplink data related to specific application requirements of the system include three types, i.e., network access data, random data, and periodic data, and the plurality of uplink channels are divided into three types, i.e., a network access channel, a random channel, and a periodic channel.
Referring to fig. 4, in another specific embodiment, the types of uplink data related to specific application requirements of the system include four types of network access data, emergency data, random data, and periodic data, and the plurality of uplink channels are divided into four types of network access channels, emergency channels, random channels, and periodic channels.
Referring to fig. 5, preferably, the present invention further considers that there may be a relay node in the system, and in order to take this into account, in a further specific embodiment, if there is a relay node in the system, when performing type division on the plurality of uplink channels, it is further necessary to divide a reserved relay channel, which is dedicated to transmitting data sent by the relay node.
When the uplink channel is divided, the uplink channel is divided according to the following sequence that the priority is gradually reduced: network access channel, reserved relay channel, emergency channel, periodic channel and random channel. The channel with the highest priority is divided from all the uplink channels, and then the channel with the next highest priority is divided from the rest uplink channels, and so on. Therefore, when the plurality of uplink channels are classified into types, the number of each type of channel other than the random channel needs to be determined, and the number of the network access channel, the reserved relay channel and the emergency channel can be preset, for example, one network access channel, one reserved relay channel and one emergency channel are all provided. Specifically, the number Nz of the periodic channels is equal to (Nc × Tz)/T, and if Nz thus calculated is not an integer, Nz needs to be rounded and then incremented by one, where T represents the transmission period of the periodic data, Nc represents the number of the preset terminal nodes, and Tz represents the slot length of the periodic data. For example, if the number Nc of the preset terminal nodes is 20, the slot length Tz of the periodic data is 30s, and the transmission period T of the periodic data is 10min, the number Nz (20 × 30s)/10min of the periodic channels is 1. If the number Nc of the predetermined terminal nodes is 22, Nz (22 × 30s)/10min is 1.1 and is not an integer, and therefore, N1 is obtained by rounding up and adding one.
For example, assume that a plurality of uplink channels preset in the system are F0-F7, the number of preset network access channels, reserved relay channels, and emergency channels is 1, and the number of the periodic channels obtained by the pre-calculation is 2. Assuming that the types of uplink data related to the specific application requirements of the system only include three types of network access data, random data and periodic data, F0 is divided into network access channels, then F7 and F6 are divided into periodic channels, the remaining F1-F5 are random channels, and the division results are shown in fig. 3. Assuming that the demand is changed now and the new demand increases the urgent data, F0 is divided into an access channel, F1 is divided into an urgent channel, F7 and F6 are divided into periodic channels, and the remaining F2-F5 are random channels, and the division result is shown in fig. 4. Assuming that a relay node is added in the existing system, F0 is divided into an access channel, F1 is divided into a reserved relay channel, F2 is divided into an emergency channel, F7 and F6 are divided into periodic channels, the remaining F3-F5 are random channels, and the division result is shown in fig. 5.
In addition, in the invention, the network access channel, the reserved relay channel and the emergency channel are divided one by one from F0, and the periodic channel is divided one by one from F7, so that the emergency channel and the periodic channel are ensured to be distributed at two sides of the random channel, because whether the channel number meets the requirement needs to be verified after the channel number is divided, the channel number of the emergency channel or the periodic channel possibly needs to be updated, the random channel is placed in the middle, and the same type of channels can be ensured to be concentrated into one even if the number of the emergency channel and the periodic channel is changed, thereby being convenient for management.
And S100c2, determining the time length of the uplink effective time interval to meet the uplink requirement of the random data according to the number of preset terminal nodes, the time slot length of the random data and the number of random channels.
In the present invention, the uplink requirement of the random data is: dividing the uplink effective time interval into a plurality of random time slots according to the time slot length of the random data, grouping all the terminal nodes in a mode that a plurality of terminal nodes are in a group, wherein the number of the terminal nodes in each group meets the probability standard of random data transmission, and the random channels and the random time slots distributed to the terminal nodes in each group are not identical to the random channels and the random time slots of other terminal nodes. The term "not completely identical" means that the two parameters of the random channel and the random time slot cannot be the same, and at least one of the two parameters is different, so that it can be ensured that the random data of at least one terminal node in each group of terminal nodes can be transmitted without collision with the random data of the terminal nodes in other groups. In addition, whether the random time slots are the same or not is compared by the time position of the random time slot in a single uplink effective time interval or a single small period.
For example, if the number of random channels is Ns, the number of preset terminals is Nc, and the probability criterion for random data transmission is that the success probability of random data transmission is greater than or equal to P, then the number Nx of terminal nodes in each group indicates that the terminal nodes in the same group are in a contention relationship, and their contention success rate 1/Nx is also the success probability, so Nx should satisfy: if M calculated by this method is not an integer, M needs to be rounded and then incremented by one. Assuming that one uplink effective time interval is composed of k random time slots, and the length of each random time slot is the time slot length Ts of random data, k needs to satisfy: k × Ns ≧ M, so that a suitable k can be determined, the time length of the uplink validity time interval can be k × Ts.
S100c3, verifying whether the number of the periodic channels meets the uplink requirement of the periodic data or not according to the number of preset terminal nodes, the time slot length of the periodic data and the time length of the uplink effective time interval, and if the number of the periodic channels does not meet the uplink requirement of the periodic data, directly re-determining the time length of the uplink effective time interval or re-determining the time length of the uplink effective time interval after updating the numbers of the periodic channels and the random channels until the number of the periodic channels and the random channels passes the verification;
in the present invention, the uplink requirement of the periodic data is:
1) the sending period of the periodic data is integral multiple of a small period, and the small period is composed of a downlink effective time interval, an uplink effective time interval and a waiting time interval. If the time length of the uplink effective time interval is not integral multiple, the time length of the uplink effective time interval can be directly determined again to meet the requirement. Therefore, the terminal can be ensured to transmit the periodic data in a certain fixed period time slot in the uplink effective time interval.
2) Dividing all the uplink effective time intervals of K continuous small periods into a plurality of periodic time slots according to the time slot length of periodic data, wherein the periodic channel and the periodic time slot allocated to each terminal node are not identical to the periodic channel and the periodic time slot of other terminal nodes, and K is a positive integer and is determined by the ratio of the transmission period of the periodic data to the small period. The term "not identical" means that two parameters, namely, the periodic channel and the periodic time slot, cannot be the same, and at least one of the two parameters is different, so that it can be ensured that the periodic data of each terminal node can be transmitted without collision. Whether the periodic time slots are the same or not is compared with the time positions of the periodic time slots in the K consecutive small periods.
And S100c4, verifying whether the quantity of the emergency channels meets the uplink requirement of the emergency data according to the time slot length of the emergency data and the time length of the uplink effective time interval, and if the quantity of the emergency channels does not meet the uplink requirement of the emergency data, directly re-determining the time length of the uplink effective time interval or re-determining the time length of the uplink effective time interval after updating the quantity of the emergency channels and the random channels until the verification is passed.
Of course, if the emergency channel is not divided in step S100c1, this step is not performed.
Wherein, the uplink demand of the emergency data comprises:
1) capacity requirements, for example, guarantee that 5% of the end nodes transmit emergency data.
For example, if there are 30 terminal nodes, it is necessary to ensure that x ═ ceil (30 × 5%) -2 terminals can transmit urgent data, where ceil () represents rounding up.
2) It is necessary to check whether the relevant criterion meets the established conclusions about Aloha, for example, to guarantee throughput, the duty cycle should preferably not exceed 30%. Of course, 30% here is merely illustrative, and in practice the slot _ aloha theoretically has a maximum time utilization of 36.8%.
The duty cycle refers to: the ratio of the time slot length of the emergency data to the time length of the uplink valid time interval. Assuming that the transmission time of a single urgent data is t, the uplink time of the current terminal is Tu, and the urgent data channel is n, the duty ratio P is calculated as: p ═ ceil (x/n)) × t/Tu, the current parameter can be considered satisfactory if P < 30%. If the calculation result P > 30%, the urgent channel needs to be added, for example, an urgent channel needs to be added, which may be implemented by changing one of the random channels to the urgent channel, which results in a change in the number of urgent channels, and it is necessary to return to step S100c2 to re-determine the time length of the uplink valid time interval.
And S100c5, allocating specific periodic channels and periodic time slots for the periodic data, and allocating specific random channels and random time slots for the random data.
Preferably, the number of terminal nodes input in advance is the maximum terminal node number required by the application. In the communication process, the number of the terminal nodes may vary, and a partition interval may be set for the number of the terminal nodes, for example, the number of the terminal nodes input in advance is 50, and the partition interval may be divided into an interval of terminal node number from 40 to 50, an interval of terminal node number from 30 to 40, and so on. Once the number of terminal nodes on line is switched from one interval to another interval, and it can be considered that the number of terminal nodes on line changes in stages, preferably, the method of the present invention further includes: when the service node works in the data processing state in the waiting time interval, the number of the online terminal nodes is determined (specifically, the service node can judge whether the terminal node is offline through the periodic data of the terminal node, and similarly, the terminal node can judge whether the gateway is abnormal through the periodic downlink data of the service node), and when the number of the online terminal nodes changes in a staged manner, the uplink communication parameters are re-determined. Referring to steps S100c1-S100c5, the specific way of re-determining the uplink communication parameters is to refer to steps S100c1-S100c5, except that the number of the terminal nodes is no longer the number of the preset terminal nodes, but the maximum value of the newly switched-in terminal node number interval, for example, the current terminal node number is changed from 15 to 25, that is, a terminal node number area of 20-30 is switched in, and only the number of the preset terminal nodes in the steps S100c1-S100c5 needs to be replaced by the terminal node number of 30 when the steps S100c1-S100c5 are executed again.
Based on the same inventive concept, the invention also discloses an LoRa communication system, which comprises a service node and a plurality of terminal nodes, wherein the LoRa communication system realizes communication based on the method.
In summary, the LoRa communication method and the LoRa communication system of the present invention have the following advantages: in the invention, a downlink effective time interval and an uplink effective time interval are set, wherein the downlink effective time interval only contains downlink data, and the uplink effective time interval only contains uplink data, so that the downlink data and the uplink data do not conflict; in addition, for the uplink data, the invention sends various types of data to corresponding various types of uplink channels, that is, different uplink channels are allocated to the uplink data, so that the conflict between the uplink data can be reduced, and in summary, the invention can achieve the effects of improving the system throughput and reducing the data collision.
While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (11)
1. An LoRa communication method applicable to an LoRa communication system including a service node and a plurality of terminal nodes, the method comprising:
entering a downlink effective time interval, and in the downlink effective time interval: the service node works in a sending state and sends downlink data to a downlink channel; the plurality of terminal nodes work in a receiving state and receive the downlink data from the downlink channel;
entering an uplink effective time interval after the downlink effective time interval is ended, and in the uplink effective time interval: the plurality of terminal nodes work in a sending state and send various types of data to corresponding various types of uplink channels; the service node works in a receiving state and receives corresponding various types of uplink data from various types of uplink channels;
and entering the downlink effective time interval again after the uplink effective time interval is ended.
2. The method of claim 1, further comprising:
and entering a waiting time interval after the uplink effective time interval is finished, wherein the service node and the plurality of terminal nodes all work in a data processing state in the waiting time interval, and entering the downlink effective time interval after the waiting time interval is finished.
3. The method according to claim 2, further comprising, before entering the downlink validity time interval for the first time, the serving node performing the steps of:
determining the time slot lengths of downlink data and various types of uplink data;
determining downlink communication parameters, including: determining the time length of the downlink effective time interval according to the time slot length of the downlink data;
determining uplink communication parameters, including: and determining classification results of a plurality of preset uplink channels in the system, the time length of the uplink effective time interval and the time slot allocation results of part types of uplink data with relatively low real-time requirements according to the type of the uplink data, the time slot length of various types of uplink data and the number of preset terminal nodes related to the specific application requirements of the system.
4. The method of claim 3, further comprising:
and when the service node works in a data processing state in the waiting time interval, determining the number of the online terminal nodes, and re-determining the uplink communication parameters when the number of the online terminal nodes changes in a staged manner.
5. The method according to claim 3, wherein the type of uplink data involved in the specific application requirements of the system includes network access data, random data, and periodic data, and the determining the uplink communication parameters specifically includes:
performing type division on the plurality of uplink channels: dividing the plurality of uplink channels into three types of network access channels, random channels and periodic channels;
determining the time length of the uplink effective time interval to meet the uplink requirement of the random data according to the number of preset terminal nodes, the time slot length of the random data and the number of random channels;
verifying whether the number of the periodic channels meets the uplink requirement of the periodic data or not according to the number of preset terminal nodes, the time slot length of the periodic data and the time length of the uplink effective time interval, and if the number of the periodic channels does not meet the uplink requirement of the periodic data, directly re-determining the time length of the uplink effective time interval or re-determining the time length of the uplink effective time interval after updating the numbers of the periodic channels and the random channels until the verification is passed;
and allocating specific periodic channels and periodic time slots for the periodic data, and allocating specific random channels and random time slots for the random data.
6. The method of claim 5, wherein determining the uplink communication parameter further comprises:
if the type of uplink data related to the specific application requirements of the system also includes emergency data, the type of the emergency channel needs to be divided when the types of the plurality of uplink channels are divided;
after the time length of the uplink effective time interval is determined, whether the number of the emergency channels meets the uplink requirement of the emergency data needs to be verified according to the time slot length of the emergency data and the time length of the uplink effective time interval, if the time slot length of the uplink effective time interval does not meet the uplink requirement of the emergency data, the time length of the uplink effective time interval is directly determined again, or the time length of the uplink effective time interval is determined again after the numbers of the emergency channels and the random channels are updated until the time length of the uplink effective time interval passes the verification.
7. The method of claim 5, wherein determining the uplink communication parameter further comprises:
if a relay node exists in the system, when the types of the plurality of uplink channels are divided, a reserved relay channel is also divided when the types of the plurality of uplink channels are divided, wherein the reserved relay channel is specially used for transmitting data sent by the relay node.
8. The method of claim 5, wherein the uplink requirement for periodic data is:
the sending period of the periodic data is integral multiple of a small period, and the small period consists of a downlink effective time interval, an uplink effective time interval and a waiting time interval;
and dividing all the uplink effective time intervals of K continuous small periods into a plurality of periodic time slots according to the time slot length of the periodic data, wherein the periodic channel and the periodic time slot which are distributed to each terminal node are not identical to the periodic channel and the periodic time slot of other terminal nodes, K is a positive integer and is determined by the ratio of the transmission period of the periodic data to the small period.
9. The method of claim 5, wherein the uplink requirement for the random data is: dividing the uplink effective time interval into a plurality of random time slots according to the time slot length of the random data, grouping all the terminal nodes in a mode that a plurality of terminal nodes are in a group, wherein the number of the terminal nodes in each group meets the probability standard of random data transmission, and the random channels and the random time slots distributed to the terminal nodes in each group are not identical to the random channels and the random time slots of other terminal nodes.
10. The method according to claim 3, wherein the types of uplink data involved in the specific application requirements of the system include network access data, emergency data, random data, and periodic data, and the types of the uplink channels include a network access channel, an emergency channel, a random channel, and a periodic channel;
the uplink mode of the network access data is as follows: randomly generating random signals and sending the random signals to the network access channel;
the uplink mode of the emergency data is as follows: randomly generating a random signal to be sent to the emergency channel;
the uplink mode of the periodic data is as follows: sending the periodic data of each terminal node to an allocated periodic channel in an allocated periodic time slot;
the uplink mode of the random data is as follows: and sending the random data of each terminal node to the allocated random channel in the allocated random time slot.
11. An LoRa communication system including a service node and a plurality of terminal nodes, wherein the LoRa communication system implements communication based on the method of any one of claims 1-10.
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