CN111565378B - LoRa communication method and LoRa communication system - Google Patents
LoRa communication method and LoRa communication system Download PDFInfo
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- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- 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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- H—ELECTRICITY
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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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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/12—Wireless traffic scheduling
- H04W72/1263—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
- H04W72/1273—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows of downlink data flows
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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 finished, 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 uplink data of various types from the uplink channels of various types; after the uplink effective time interval is finished, the downlink effective time interval is re-entered, and thus, the downlink data and the uplink data cannot collide; and the conflict between uplink data can be reduced, and in summary, the invention can achieve the effects of improving the throughput of the system and reducing the data collision.
Description
Technical Field
The invention relates to the field of communication, in particular to a LoRa communication method and a LoRa communication system.
Background
LoRa is a long-distance, low-power consumption, wireless communication technology suitable for Internet of things, and referring to FIG. 1, equipment in a LoRa communication system mainly comprises 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 structure is mostly adopted between the gateway and the terminal. The main chip supporting LoRa at present adopts a half duplex mode, namely, the gateway and the terminal can not simultaneously perform transmitting and receiving operations.
At present, the LoRa is mainly applied to the business such as water electric meters, the business data volume is less, the real-time requirement is generally not high, the transmission data mainly uses the Aloha (namely, the data is randomly sent), the management and working modes of the system are simpler, but the throughput of the system is lower, and the data collision probability is higher.
Disclosure of Invention
The invention aims to solve the technical problem that the data collision probability is high in the prior art, and provides a LoRa communication method and a LoRa communication system.
The technical scheme adopted for solving the technical problems is as follows: a method of constructing a LoRa communication suitable for use in a LoRa communication system comprising a serving node and a plurality of terminal nodes, the method comprising:
entering a downlink effective time interval, wherein the downlink effective time interval is as follows: 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 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 uplink data of various types from the uplink channels of various types;
And re-entering the downlink effective time interval after the uplink effective time interval is ended.
Preferably, the method further comprises:
And after the uplink effective time interval is ended, a waiting time interval is first formed, the service node and the plurality of terminal nodes work in a data processing state in the waiting time interval, and the downlink effective time interval is entered after the waiting time interval is ended.
Preferably, the method further comprises, before entering the downlink valid time interval for the first time, the serving node performing the following steps:
determining the time slot length of downlink data and various uplink data;
determining downlink communication parameters includes: determining the time length of the downlink effective time interval according to the time slot length of the downlink data;
Determining uplink communication parameters includes: and determining classification results of a plurality of uplink channels preset in the system, the time length of the uplink effective time interval and the time slot allocation result of part of uplink data with relatively low real-time requirements according to the types of the uplink data, the time slot lengths of various 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 the data processing state in the waiting time interval, determining the number of the online terminal nodes, and when the number of the online terminal nodes changes in a stepwise manner, redetermining the uplink communication parameters.
Preferably, the type of the 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:
type division is performed 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 according to the number of preset terminal nodes, the time slot length of random data and the number of random channels so as to meet the uplink requirement of the random data;
verifying whether the number of the periodic channels meets the uplink requirement of the periodic data or not according to the number of the preset terminal nodes, the time slot length of the periodic data and the time length of the uplink effective time interval, if the number of the periodic channels does not pass the verification, directly redetermining the time length of the uplink effective time interval or redetermining the time length of the uplink effective time interval after updating the number of the periodic channels and the random channels until the number of the periodic channels and the random channels pass the verification;
Specific periodic channels and periodic time slots are allocated to the periodic data, and specific random channels and random time slots are allocated to the random data.
Preferably, the determining the uplink communication parameter further includes:
if the type of the uplink data related to the specific application requirement of the system further comprises emergency data, the type of the emergency channel is further required to be divided when the types of the plurality of uplink channels are divided;
After determining the time length of the uplink effective time interval, verifying whether the number 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, if the number of the emergency channels does not pass the verification, 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 number of the emergency channels and the random channels until the number of the emergency channels and the random channels pass the verification.
Preferably, the determining the uplink communication parameter further includes:
if a relay node exists in the system, when the types of the uplink channels are classified, the types of reserved relay channels are also required to be classified when the types of the uplink channels are classified, and the reserved relay channels are special for transmitting data sent by the relay node.
Preferably, the uplink requirements of the periodic data are:
The transmission period of the periodic data is an integer 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;
And dividing the uplink effective time intervals of all continuous K small periods into a plurality of period time slots according to the time slot lengths of the period data, wherein the period channels and the period time slots distributed to each terminal node are not identical with the period channels and the period time slots of other terminal nodes, K is a positive integer and is determined by the ratio of the transmission period and the small period of the period data.
Preferably, the uplink requirement of the random data is: dividing the time slot length of the random data into a plurality of random time slots from the uplink effective time interval, grouping all the terminal nodes in a mode that a plurality of terminal nodes are taken as a group, wherein the number of each group of terminal nodes accords with the probability standard of random data transmission, and the random channels and the random time slots allocated to each group of terminal nodes are not completely the same as the random channels and the random time slots of other terminal nodes.
Preferably, the types of uplink data related to specific application requirements of the system comprise network access data, emergency data, random data and periodic data, and the types of uplink channels comprise network access channels, emergency channels, random channels and periodic channels;
The uplink mode of the network access data is as follows: randomly generating random and transmitting the random to the network access channel;
the uplink mode of the emergency data is as follows: randomly generating random data and transmitting the random data to the emergency channel;
The uplink mode of the periodic data is as follows: the periodic data of each terminal node is sent to an allocated periodic channel in the allocated periodic time slot;
The uplink mode of the random data is as follows: the random data of each terminal node is transmitted to the allocated random channel in the allocated random time slot.
The invention also discloses a LoRa communication system, which comprises a service node and a plurality of terminal nodes, and 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 cannot collide; in addition, for uplink data, the invention transmits various types of data to corresponding various uplink channels, namely different uplink channels are allocated for 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 throughput of the system and reducing the data collision.
Drawings
For a clearer description of an embodiment of the invention or of a technical solution in the prior art, the drawings that are needed in the description of the embodiment or of the prior art will be briefly described, it being obvious that the drawings in the description below are only embodiments of the invention, and that other drawings can be obtained, without inventive effort, by a person skilled in the art from the drawings provided:
FIG. 1 is a schematic diagram of a LoRa communication system;
FIG. 2 is a flow chart of a communication method of the present invention;
FIG. 3 is a schematic 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
In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Exemplary embodiments of the present invention are illustrated in the accompanying 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 herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
The invention has the following general ideas: in the LoRa communication system, after the downlink effective time interval is finished, the uplink effective time interval is entered, after the uplink effective time interval is finished, the downlink effective time interval is entered again, and the cycle 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 regarded as a small period, the cycle is equivalent to repeating with a set small period, and each small period can exclusively carry out data downlink in the downlink effective time interval and exclusively carry out data uplink in the uplink effective time interval, so that downlink data and uplink data cannot conflict. In addition, for the uplink situation, the terminal node sends various types of data to the corresponding various types of uplink channels, that is to say, different uplink channels are allocated to the uplink data, so that collision among the uplink data can be reduced, and finally, the invention can achieve the effects of improving system throughput and reducing data collision.
In order to better understand the above technical solutions, the following detailed description will be made with reference to the accompanying drawings and specific embodiments, and it should be understood that specific features in the embodiments and examples of the present application are detailed descriptions of the technical solutions of the present application, and not limit the technical solutions of the present application, and the technical features in the embodiments and examples of the present application may be combined with each other without conflict.
Referring to fig. 2, a flow chart of the communication method of the present invention is shown. The present invention is applicable to a LoRa communication system comprising 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 in particular, reference is made to fig. 1.
The communication method of the present invention comprises:
S101, entering a downlink effective time interval, wherein the downlink effective time interval is: 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, wherein the uplink effective time interval is: the 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 uplink data of various types from the uplink channels of various types;
The LoRa communication system may be applied to various practical applications, the types of uplink data involved may be different, and a specific application may also be different due to the different types of uplink data required by different requirements, but in general, the types of uplink data generally include several of network access data, emergency data, random data, and periodic data. The network access data represents data which is accessed to the network for the first time or is accessed to the network again offline 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, which represents data which is randomly generated and has lower real-time requirements; and the periodic data represents data which needs to be transmitted at a fixed time for each terminal. These types of data may not exist depending on the actual application of the LoRa communication system, for example: real-time is not required for practical applications, and then urgent data does not exist.
In the invention, each type of uplink data is allocated with a special uplink channel of a corresponding type, for example, the types of uplink channels respectively corresponding to network access data, emergency data, random data and periodic data are as follows: an access channel, an emergency channel, a random channel, a 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. The Aloha scheme is that data is completely randomly transmitted in time, and the Slot Aloha is that time is divided into time slices, and data can only be transmitted at a specified starting point. Performance distinction between slot-Aloha and Aloha modes: the Aloha delay is smaller (under the same condition), but the system data throughput of the slot_ Alohad is 2 times that of the Aloha (theoretically), so that if the Aloha is used for directly sending the network access data, the method is simpler, and if the slot_aloha is used for needing a synchronization starting point, the method can be adopted to consider that the synchronization time starting point is firstly monitored by downlink data before sending the network access data in the system, obviously, the method of the Aloha is simpler in complexity, and in summary, the method can be adopted to comprehensively measure according to the complexity, the real-time requirement and the throughput performance. 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 the periodic data of each terminal node is sent to the allocated periodic channel in the allocated periodic time slot. The uplink mode of the random data is as follows: the random data of each terminal node is transmitted to the allocated random channel in the allocated random time slot. Here, the time slot is actually a time slot.
S103, entering a waiting time interval after the uplink effective time interval is ended, 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 ended.
In theory, after one time interval is finished, the user may immediately enter the next time interval, or may wait for a certain time before entering the next time interval. Referring to fig. 3 to 5, the horizontal axis in the figure represents a channel, the vertical axis represents a time, td in the figure represents a downlink effective time zone, tu represents an uplink effective time zone, and Tw represents a waiting time zone. Td, tu, tw together form a small period Ta, and the whole system, whether a service node or a terminal node, synchronously and repeatedly enters the small period Ta, in other words, the whole communication process is equivalent to splicing a plurality of small periods Ta.
In the above steps S101-S103, various communication parameters are involved, 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 part type (such as random data and periodic data) with relatively low real-time requirement. These communication parameters may be predetermined at the initialization of the service node, for which purpose the method of the invention further comprises: before entering the downlink valid time interval for the first time, i.e. before entering step S101, the service node performs the following steps S100a-S100c.
S100a, determining the time slot length of downlink data and various uplink data.
Specifically, the time slot lengths of the downlink data and the uplink data can be calculated according to the data lengths of the pre-input downlink data and the uplink data 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 gadget, and the gadget can directly calculate and obtain the theoretical transmission time of the gateway chip based on the data length and the adopted SF. After the theoretical transmission time is calculated, a certain multiple (for example, 1.2 times) can be enlarged on the basis of the theoretical transmission time to obtain the downlink time slot length of the gateway, namely, the downlink data time slot length. The method for determining the slot lengths of the periodic data, the random data and the urgent data is the same and will not be described here 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 the downlink data.
S100c, determining uplink communication parameters, including: and determining classification results of a plurality of uplink channels preset in the system, the time length of the uplink effective time interval and the time slot allocation result of part of uplink data with relatively low real-time requirements according to the types of the uplink data, the time slot lengths of various 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 parameters in step S100c specifically includes:
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 the specific application requirements of the system include three types of network access data, random data and periodic data, and the plurality of uplink channels are divided into three types of network access channels, random channels and periodic channels.
Referring to fig. 4, in another specific embodiment, the types of uplink data related to the 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, in order to consider that a relay node may be provided in the system, in a further specific embodiment, if a relay node exists in the system, a type of reserved relay channel is further required to be divided when the types of the uplink channels are divided, where the reserved relay channel is dedicated to transmitting data sent by the relay node.
The invention divides the uplink channel successively according to the order of successively decreasing priority: an access channel, a reserved relay channel, an emergency channel, a periodic channel, a random channel. The highest priority channel is firstly divided from all the uplink channels, then the next highest priority channel is divided from the rest uplink channels, and the like. Therefore, when the uplink channels are classified, the number of each of the other types of channels except the random channel needs to be determined, and the number of the channel types can be preset for the network access channel, the reserved relay channel and the emergency channel, for example, the number of the network access channel, the reserved relay channel and the emergency channel is one. For the periodic channels, the number of the periodic channels is determined by the preset number of the terminal nodes, the time slot length of the periodic data and the transmission period of the periodic data, specifically, the number Nz of the periodic channels is equal to (nc×tz)/T, if the calculated Nz is not an integer, the number Nz needs to be rounded and added by one, wherein T represents the transmission period of the periodic data, nc represents the preset number of the terminal nodes, and Tz represents the time slot length of the periodic data. For example, the number Nc of preset terminal nodes is 20, the time slot length Tz of the periodic data is 30s, and the transmission period T of the periodic data is 10min, and then the number Nz (20×30s)/10 min=1 of the periodic channels. If the number Nc of preset terminal nodes is 22, nz= (22×30 s)/10 min=1.1 is not an integer, so that N1 = 2 is obtained by rounding up and adding one.
For example, assuming that a plurality of preset uplink channels in the system are F0-F7, the number of preset network access channels, preset relay channels and preset emergency channels is 1, and the number of pre-calculated periodic channels is 2. Assuming that the types of uplink data related to specific application requirements of the system only comprise three types of network access data, random data and periodic data, firstly dividing F0 into network access channels, then dividing F7 and F6 into periodic channels, and the rest F1-F5 are random channels, wherein the dividing result is shown in figure 3. Assuming that the new demand is changed now and emergency data is added, F0 is firstly divided into network access channels, F1 is divided into emergency channels, F7 and F6 are divided into periodic channels, and the rest 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, firstly F0 is divided into network access channels, then F1 is divided into reserved relay channels, then F2 is divided into emergency channels, then F7 and F6 are divided into periodic channels, and the rest F3-F5 are random channels, wherein the division result is shown in figure 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, thus ensuring that the emergency channel and the periodic channel are distributed on both sides of the random channel.
S100c2, determining the time length of the uplink effective time interval according to the preset number of terminal nodes, the time slot length of the random data and the number of random channels so as to meet the uplink requirement of the random data.
In the invention, the uplink requirements of the random data are as follows: dividing the time slot length of the random data into a plurality of random time slots from the uplink effective time interval, grouping all the terminal nodes in a mode that a plurality of terminal nodes are taken as a group, wherein the number of each group of terminal nodes accords with the probability standard of random data transmission, and the random channels and the random time slots allocated to each group of terminal nodes are not completely the same as the random channels and the random time slots of other terminal nodes. By not exactly the same, it is meant that the two parameters, namely the random channel and the random time slot, cannot be both the same, and at least one of them is different, so that it is ensured that the random data of at least one terminal node in each group of terminal nodes can be transmitted and will not collide with the random data of other groups of terminal nodes. In addition, whether the random time slots are the same or not is compared by the time positions of the random time slots 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 probability of success of random data transmission is P or more, then the number Nx of terminal nodes in each group is obviously a competition relationship, and their competition success rate is 1/Nx, that is, the probability of success is the above, so Nx should satisfy: 1/Nx is greater than or equal to P, so that Nx can be determined first, the number of packets is M=Nc/Nx, and if M calculated by the method is not an integer, M is required to be rounded and then added by one. Assuming that one uplink effective time interval is formed by k random time slots, and the length of each random time slot is the time slot length Ts of the random data, k needs to be satisfied: and k is greater than or equal to M, so that proper k can be determined, and the time length of the uplink effective time interval can be k×Ts.
S100c3, verifying whether the number of the periodic channels meets the uplink requirement of the periodic data according to the number of the preset terminal nodes, the time slot length of the periodic data and the time length of the uplink effective time interval, if the number of the periodic channels does not pass the verification, directly redetermining the time length of the uplink effective time interval or redetermining the time length of the uplink effective time interval after updating the number of the periodic channels and the random channels until the number of the periodic channels and the random channels pass the verification;
In the present invention, the uplink requirements of the periodic data are:
1) The transmission period of the period data is an integer 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 is not integral multiple, the time length of the uplink effective time interval can be directly redetermined to meet the requirement. Thus, the terminals can be ensured to transmit the periodic data in a certain fixed periodic time slot in the uplink effective time interval.
2) Dividing the time slot length of the periodic data into a plurality of periodic time slots from all uplink effective time intervals of continuous K small periods, wherein the periodic channels and the periodic time slots distributed to each terminal node are not identical with the periodic channels and the periodic time slots of other terminal nodes, K is a positive integer and is determined by the ratio of the transmission period to the small period of the periodic data. By not exactly the same, it is meant that the two parameters, periodic channel and periodic time slot, cannot be both the same, at least one of which is different, so that it is ensured that the periodic data of each terminal node can be transmitted without collision. In addition, whether the periodic time slots are identical or not is compared by the time positions of the periodic time slots in the continuous K small periods.
S100c4, verifying whether the number 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, if the number of the emergency channels does not pass the verification, directly redetermining the time length of the uplink effective time interval or redetermining the time length of the uplink effective time interval after updating the number of the emergency channels and the random channels until the number of the emergency channels and the random channels pass the verification.
Of course, if the emergency channel is not divided in step S100c1, this step is not performed.
The uplink requirement of the emergency data includes:
1) Capacity requirements, for example, ensure that 5% of the end nodes transmit emergency data.
For example, there are 30 terminal nodes, and it is guaranteed that x=ceil (30×5%) =2 terminals can transmit urgent data, where ceil () represents a round-up.
2) It is necessary to check whether the relevant index meets the already existing conclusion about Aloha, for example, in order to guarantee throughput, the duty cycle should preferably not exceed 30%. Of course, 30% is only illustrative here, and in practice slot aloha theoretically has a maximum time utilization of 36.8%.
The duty cycle is: the ratio between the time slot length of the emergency data and the time length of the uplink effective time interval. Assuming that the transmission time of the single emergency data is t, the uplink time of the current terminal is Tu, and the emergency data channel is n, the duty cycle P is calculated as follows: p= (ceil (x/n)) × t/Tu, the current parameters may be considered to meet the requirements if P < 30%. If the calculation result P is greater than 30%, an emergency channel needs to be added, for example, an emergency channel needs to be added, which may be achieved by changing one of the random channels to an emergency channel, which causes a change in the number of emergency channels, and thus, the step S100c2 needs to be returned to redetermine the time length of the uplink valid time interval.
And S100c5, allocating a specific periodic channel and a periodic time slot for the periodic data, and allocating a specific random channel and a random time slot for the random data.
Preferably, the number of terminal nodes which we input in advance is the maximum number of terminal nodes 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 may be divided into 40-50 into one terminal node number interval, 30-40 into one terminal node number interval, and so on. Once the number of terminal nodes on-line is switched from one interval to another, it may be considered that the number of terminal nodes on-line changes stepwise, preferably, the method of the present invention further comprises: 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 nodes are offline or not through the period data of the terminal nodes, similarly, the terminal node can judge whether the gateway is abnormal or not through the period downlink data of the service node), and when the number of the online terminal nodes is changed in a stepwise manner, the uplink communication parameters are redetermined. The specific way to redetermine the uplink communication parameters refers to steps S100c1-S100c5, except that the number of terminal nodes is no longer the preset number of terminal nodes, but the maximum value of the newly cut-in terminal node number interval, for example, the current terminal node number is changed from 15 to 25, i.e. the terminal node number area cut-in 20-30, and then only the preset number of terminal nodes is replaced by the terminal node number 30 when steps S100c1-S100c5 are executed again.
Based on the same inventive concept, the invention also discloses a 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 cannot collide; in addition, for uplink data, the invention transmits various types of data to corresponding various uplink channels, namely different uplink channels are allocated for 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 throughput of the system and reducing the data collision.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are to be protected by the present invention.
Claims (8)
1. A method of LoRa communication adapted for use in a LoRa communication system comprising a serving node and a plurality of terminal nodes, the method comprising:
entering a downlink effective time interval, wherein the downlink effective time interval is as follows: 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 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 uplink data of various types from the uplink channels of various types;
A waiting time interval is first formed after the uplink effective time interval is finished, the service node and the plurality of terminal nodes work in a data processing state in the waiting time interval, and the downlink effective time interval is reentered after the waiting time interval is finished;
the method further comprises, before entering the downlink valid time interval for the first time, the service node performing the following steps:
determining the time slot length of downlink data and various uplink data;
determining downlink communication parameters includes: determining the time length of the downlink effective time interval according to the time slot length of the downlink data;
Determining uplink communication parameters includes: determining classification results of a plurality of uplink channels preset in the system, time length of the uplink effective time interval and time slot allocation results of partial uplink data with relatively low real-time requirements according to types of uplink data related to specific application requirements of the system, time slot lengths of various uplink data and the number of preset terminal nodes;
the type of the uplink data related to the specific application requirement of the system comprises network access data, random data and periodic data, and the determining of the uplink communication parameters specifically comprises:
type division is performed 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 according to the number of preset terminal nodes, the time slot length of random data and the number of random channels so as to meet the uplink requirement of the random data;
verifying whether the number of the periodic channels meets the uplink requirement of the periodic data or not according to the number of the preset terminal nodes, the time slot length of the periodic data and the time length of the uplink effective time interval, if the number of the periodic channels does not pass the verification, directly redetermining the time length of the uplink effective time interval or redetermining the time length of the uplink effective time interval after updating the number of the periodic channels and the random channels until the number of the periodic channels and the random channels pass the verification;
Specific periodic channels and periodic time slots are allocated to the periodic data, and specific random channels and random time slots are allocated to the random data.
2. The method according to claim 1, wherein the method further comprises:
And when the service node works in the data processing state in the waiting time interval, determining the number of the online terminal nodes, and when the number of the online terminal nodes changes in a stepwise manner, redetermining the uplink communication parameters.
3. The method of claim 1, wherein said determining uplink communication parameters further comprises:
if the type of the uplink data related to the specific application requirement of the system further comprises emergency data, the type of the emergency channel is further required to be divided when the types of the plurality of uplink channels are divided;
After determining the time length of the uplink effective time interval, verifying whether the number 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, if the number of the emergency channels does not pass the verification, 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 number of the emergency channels and the random channels until the number of the emergency channels and the random channels pass the verification.
4. The method of claim 1, wherein said determining uplink communication parameters further comprises:
if a relay node exists in the system, when the types of the uplink channels are classified, the types of reserved relay channels are also required to be classified when the types of the uplink channels are classified, and the reserved relay channels are special for transmitting data sent by the relay node.
5. The method of claim 1, wherein the uplink requirements for the periodic data are:
The transmission period of the periodic data is an integer 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;
And dividing the uplink effective time intervals of all continuous K small periods into a plurality of period time slots according to the time slot lengths of the period data, wherein the period channels and the period time slots distributed to each terminal node are not identical with the period channels and the period time slots of other terminal nodes, K is a positive integer and is determined by the ratio of the transmission period and the small period of the period data.
6. The method of claim 1, wherein the uplink requirements for the random data are: dividing the time slot length of the random data into a plurality of random time slots from the uplink effective time interval, grouping all the terminal nodes in a mode that a plurality of terminal nodes are taken as a group, wherein the number of each group of terminal nodes accords with the probability standard of random data transmission, and the random channels and the random time slots allocated to each group of terminal nodes are not completely the same as the random channels and the random time slots of other terminal nodes.
7. The method according to claim 1, wherein the type of uplink data related to the specific application requirement of the system comprises network access data, emergency data, random data and periodic data, and the type of uplink channel comprises network access channel, emergency channel, random channel and periodic channel;
The uplink mode of the network access data is as follows: randomly generating random and transmitting the random to the network access channel;
the uplink mode of the emergency data is as follows: randomly generating random data and transmitting the random data to the emergency channel;
The uplink mode of the periodic data is as follows: the periodic data of each terminal node is sent to an allocated periodic channel in the allocated periodic time slot;
The uplink mode of the random data is as follows: the random data of each terminal node is transmitted to the allocated random channel in the allocated random time slot.
8. A LoRa communication system comprising a service node and a plurality of end nodes, wherein the LoRa communication system is adapted to communicate based on the method of any of claims 1-7.
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