A communication method and apparatus

Abstract

Embodiments of the present application provide a communication method and device, wherein the device comprises a processing unit and a transceiver unit, the processing unit is configured to generate a downlink excitation signal carrying first information and N downlink instructions, and the transceiver unit is configured to send the downlink excitation signal to N groups of tag nodes within a signal coverage range of the device. The first information comprises M uplink rates supported by this query and the number of groups of tag nodes supported by each of the M uplink rates. Each downlink instruction carries a target group identifier. The downlink instruction is used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal. M and N are integers greater than 1. The device sends the M uplink rates supported by this query and the number of groups of each uplink rate to each group of tag nodes, so that each group of tag nodes can select an uplink rate by itself, thereby transmitting the uplink reflection signal at a reasonable uplink rate and improving the access efficiency of the tag nodes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication, and in particular to a communication method and device. BACKGROUND

[0002] Modulated backscatter communication is a communication technology suitable for low cost and low power systems, and is suitable for scenarios such as the Internet of Things (IoT) which are sensitive to power consumption. In the modulated backscatter communication technology, three nodes can be included: a transmitter, a tag node, and a receiver. The transmitter and the receiver can also be integrated into the same node, which can be referred to as a card reader. The transmitter can send a wireless signal, which can also be referred to as a downlink excitation signal. After the tag node receives the downlink excitation signal, it can modulate the data to be sent onto the downlink excitation signal to obtain an uplink reflection signal and send the reflection signal to the receiver. After the receiver receives the uplink reflection signal, it can demodulate the data carried by the uplink reflection signal.

[0003] In a conventional modulated backscatter communication system, the transmitter can be a relay node, the tag node can be a radio frequency identification (RFID) chip, and the receiver can be a base station. The relay node can send a downlink excitation signal to multiple tag nodes, and the base station can receive uplink reflection signals from multiple tag nodes. In the conventional modulated backscatter communication system, the coverage range of the base station is generally within 20 meters. For communication between a base station or card reader and all tag nodes, the downlink transmission rate used by the base station or card reader is the same, and the uplink transmission rate used by all tag nodes is also the same. However, with the advancement of technology, the signal coverage range of the communication system has expanded, for example, from a transmission distance of 20 meters to 100 meters or even more. If all tag nodes still use the same uplink transmission rate to communicate with the base station or card reader, it will result in too low access efficiency or even be unable to access. SUMMARY

[0004] Embodiments of the present application provide a communication method and device to improve the access efficiency of tag nodes.

[0005] In a first aspect, an embodiment of the present application provides a communication method, comprising: generating, by a first node, a downlink excitation signal carrying first information and N downlink instructions; wherein the first information comprises M uplink rates supported by this query and the number of groups of tag nodes supported by each of the M uplink rates, each downlink instruction carries a target group identifier, and the downlink instruction is used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal, M and N are integers greater than 1; and sending, by the first node, the downlink excitation signal to N groups of tag nodes within a signal coverage range of the first node.

[0006] In an embodiment of the present application, the first node sends the M uplink rates supported by this query and the number of groups of each uplink rate to each group of tag nodes, so that each group of tag nodes can select an uplink rate by itself, thereby transmitting the uplink reflection signal at a reasonable uplink rate and improving the access efficiency of the tag nodes.

[0007] In a possible design, the first node sends the downlink excitation signal to N groups of tag nodes within a signal coverage range of the first node, and there can be multiple implementation manners.

[0008] In implementation manner one, the first node can send the downlink excitation signal to the N groups of tag nodes by using a time division duplex (TDD) frame, and the N downlink instructions included in the TDD frame are transmitted in a TDD manner.

[0009] In implementation manner two, the first node can send the downlink excitation signal to the N groups of tag nodes by using a TDD and frequency division duplex (FDD) multiplex frame, and each of the N downlink instructions included in the TDD and FDD multiplex frame is transmitted in a TDD manner or an FDD manner.

[0010] In this implementation manner two, compared with the TDD frame used to send the downlink excitation signal in implementation manner one, the transmission efficiency can be improved.

[0011] In a possible design, the downlink excitation signal is obtained by using amplitude modulation, so that each group of tag nodes is not interfered by the signals received by other groups of tag nodes, and can demodulate the downlink instruction sent to itself.

[0012] In a possible design, the downlink excitation signal further carries a charging bit, and the charging bit is used to instruct a tag node receiving the first information to select an uplink rate for sending the uplink reflection signal. By sending the charging bit, sufficient time can be given to each group of tag nodes to select the uplink rate.

[0013] In a possible design, if the first uplink rate supports a group of tag nodes and the second uplink rate supports n groups of tag nodes, the second uplink rate is greater than or equal to n times the first uplink rate; where the first uplink rate is any one of the M uplink rates, and the second uplink rate is any one of the M uplink rates except the first uplink rate.

[0014] In a possible design, the downlink instruction includes a Query instruction or a non-Query instruction.

[0015] In a second aspect, an embodiment of the present application provides a communication method, which can be applied to any tag node in N groups of tag nodes in a modulation reflection communication system, and the method comprises the following steps.

[0016] In the embodiment of the present application, the tag nodes can select uplink rates by themselves, and different groups of tag nodes can select different uplink rates to send uplink reflection signals according to the signal strength of the received downlink excitation signals, so that each group of tag nodes can transmit uplink reflection signals at reasonable uplink rates, and the access efficiency of the tag nodes is improved.

[0017] In a possible design, the first tag node sending the uplink reflection signal to the second node at the selected uplink rate can include the following steps.

[0018] In a possible design, the first tag node receiving the downlink excitation signal from the first node can have various implementation manners.

[0019] In a first implementation, the first tag node receives a downlink excitation signal sent by the first node using a TDD frame; and the N downlink instructions included in the TDD frame are transmitted using a TDD mode.

[0020] In a second implementation, the first tag node receives a downlink excitation signal sent by the first node using a TDD and FDD multiplexing frame; and in the N downlink instructions included in the TDD and FDD multiplexing frame, each downlink instruction sent at the same downlink rate is transmitted using a TDD mode, and each downlink instruction sent at a different downlink rate is transmitted using an FDD mode.

[0021] In the second implementation, compared with the downlink excitation signal sent using the TDD frame in the first implementation, the transmission efficiency can be improved.

[0022] In a possible design, the downlink excitation signal is modulated using an amplitude modulation mode, so that each group of tag nodes can not be interfered by the received signals of other groups of tag nodes, and the downlink instruction sent to itself can be demodulated.

[0023] In a possible design, the downlink excitation signal further includes a charging bit, and the charging bit is used to instruct the tag node receiving the first information to select an uplink rate for sending the uplink reflection signal. By sending the charging bit, sufficient time can be given to each group of tag nodes to select the uplink rate.

[0024] In a possible design, if the first uplink rate supports one group of tag nodes, and the second uplink rate supports n groups of tag nodes, the second uplink rate is greater than or equal to n times the first uplink rate; and the first uplink rate is any one of the M uplink rates, and the second uplink rate is any one of the M uplink rates except the first uplink rate.

[0025] In a possible design, the downlink instruction includes a Query instruction or a non-Query instruction.

[0026] In a third aspect, an embodiment of the present application provides a communication method, including: receiving, by a second node, uplink reflection signals from N groups of tag nodes within a preset time length; demodulating, by the second node, the uplink reflection signals to obtain response information fed back by each group of tag nodes; determining, by the second node, tag nodes that can be accessed in this query according to the response information fed back by each group of tag nodes; and sending, by the second node, an access confirmation message to the tag nodes that can be accessed, the access confirmation message carrying an identifier of the tag nodes that can be accessed. In the method, an uplink rate used by each group of tag nodes when sending the uplink reflection signal is determined according to first information and a signal strength of a received downlink excitation signal; and the first information includes M uplink rates supported in this query and a group number of at least one group of tag nodes corresponding to each uplink rate in the M uplink rates.

[0027] In the embodiments of the present application, the second node receives the uplink reflection signals sent by the tag nodes in each group at the uplink rate selected by the tag nodes, and even in the case of expanding the signal coverage, the tag nodes in each group can transmit the uplink reflection signals at a reasonable uplink rate, thereby improving the access efficiency of the tag nodes.

[0028] In a possible design, the second node receives the uplink reflection signals from the N groups of tag nodes in a preset time length, including: the second node receives the uplink reflection signals sent by the tag nodes in each group at the first uplink rate in a time division duplex (TDD) manner in the preset time length, and receives the uplink reflection signals sent by the tag nodes in each group at the second uplink rate in a TDD manner in the preset time length; and the uplink reflection signals sent by the tag nodes in each group at the first uplink rate and the uplink reflection signals sent by the tag nodes in each group at the second uplink rate are sent in a frequency division duplex (FDD) manner.

[0029] Through the design, the tag nodes in each group send the uplink reflection signals in a TDD and FDD multiplexing manner, and the transmission efficiency can be improved.

[0030] In a possible design, the second node demodulates the uplink reflection signals to obtain the response information fed back by the tag nodes in each group, including: for the i-th uplink rate in the M uplink rates, i is a positive integer, performing: if the i-th uplink rate corresponds to one group of tag nodes, performing frequency filtering processing on the uplink reflection signals received in the preset time length to filter out other uplink reflection signals except the frequency corresponding to the i-th uplink rate, and demodulating the uplink reflection signals after the frequency filtering processing in a frequency shift keying (FSK) manner to obtain the response message sent by the tag nodes in the group corresponding to the i-th uplink rate; and if the i-th uplink rate corresponds to q groups of tag nodes, q is an integer greater than 1, equally dividing the preset time length into q time periods, performing frequency filtering processing on the uplink reflection signals received in each time period to filter out other uplink reflection signals except the frequency corresponding to the i-th uplink rate, and demodulating the uplink reflection signals after the frequency filtering processing in an FSK manner to obtain the response message sent by the tag nodes in each group corresponding to the i-th uplink rate.

[0031] Through the design, the second node can obtain the response message sent by the tag nodes in each group through frequency filtering processing and FSK demodulation, eliminate the interference of other signals (such as downlink excitation signals), and thus can accurately demodulate the response message of each tag node.

[0032] In a possible design, if the first uplink rate supports a set of label nodes, and the second uplink rate supports n sets of label nodes, the second uplink rate is greater than or equal to n times the first uplink rate; wherein the first uplink rate is any one of the M uplink rates supported by the current query, and the second uplink rate is any one of the M uplink rates except the first uplink rate.

[0033] In a fourth aspect, an embodiment of the present application provides a communication apparatus, which can be a terminal device, and can also be a chip for a terminal device. The apparatus has the function of implementing the above-described first aspect or any of the embodiments of the first aspect, or the function of implementing the above-described second aspect or any of the embodiments of the second aspect, or the function of implementing the above-described third aspect or any of the embodiments of the third aspect. The function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described functions.

[0034] In a fifth aspect, an embodiment of the present application provides a communication apparatus, which includes a processor and a memory. The memory is used to store computer-executed instructions. When the apparatus is running, the processor executes the computer-executed instructions stored in the memory, so that the apparatus performs the method of the above-described first aspect or any of the embodiments of the first aspect, or the method of the above-described second aspect or any of the embodiments of the second aspect, or the method of the above-described third aspect or any of the embodiments of the third aspect.

[0035] In a sixth aspect, an embodiment of the present application provides a communication apparatus, which includes units or means for performing each step of the above-described first aspect or any of the embodiments of the first aspect, or the second aspect or any of the embodiments of the second aspect, or the third aspect or any of the embodiments of the third aspect.

[0036] In a seventh aspect, an embodiment of the present application provides a communication apparatus, which includes a processor and an interface circuit. The processor is used to communicate with other apparatuses through the interface circuit, and perform the method of the above-described first aspect or any of the embodiments of the first aspect, or the method of the above-described second aspect or any of the embodiments of the second aspect, or the method of the above-described third aspect or any of the embodiments of the third aspect. The processor includes one or more.

[0037] In an eighth aspect, an embodiment of the present application provides a communication apparatus, which includes a processor, used to be connected with a memory, and used to call a program stored in the memory, so as to perform the method of the above-described first aspect or any of the embodiments of the first aspect, or the method of the above-described second aspect or any of the embodiments of the second aspect, or the method of the above-described third aspect or any of the embodiments of the third aspect. The memory can be located in the apparatus, or can be located outside the apparatus. The processor includes one or more.

[0038] In a ninth aspect, the embodiments of the present application further provide a computer readable storage medium, wherein instructions are stored in the computer readable storage medium, and when the instructions are run on a computer, the processor executes the method of the first aspect or any of the embodiments of the first aspect, or the method of the second aspect or any of the embodiments of the second aspect, or the method of the third aspect or any of the embodiments of the third aspect.

[0039] In a tenth aspect, the embodiments of the present application further provide a computer program product comprising instructions, which, when run on a computer, cause the computer to execute the method of the first aspect or any of the embodiments of the first aspect, or the method of the second aspect or any of the embodiments of the second aspect, or the method of the third aspect or any of the embodiments of the third aspect.

[0040] In an eleventh aspect, the embodiments of the present application further provide a chip system, comprising: a processor configured to execute the method of the first aspect or any of the embodiments of the first aspect, or the method of the second aspect or any of the embodiments of the second aspect, or the method of the third aspect or any of the embodiments of the third aspect.

[0041] In a twelfth aspect, the embodiments of the present application further provide a communication system, comprising a first node configured to execute the method of the first aspect or any of the embodiments of the first aspect, a first tag node configured to execute the method of the second aspect or any of the embodiments of the second aspect, and a second node configured to execute the method of the third aspect or any of the embodiments of the third aspect.

[0042] The technical effects brought by the fourth aspect to the twelfth aspect and any possible design thereof can refer to the technical effects brought by different design ways of the method of the embodiments of the present application, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 A schematic diagram of a communication system architecture applicable to the embodiments of the present application;

[0044] Figure 2 A schematic diagram of another communication system architecture applicable to the embodiments of the present application;

[0045] Figure 3 A schematic diagram of a downlink excitation signal provided by the embodiments of the present application;

[0046] Figure 4 A schematic diagram of another downlink excitation signal provided by the embodiments of the present application;

[0047] Figure 5 A schematic diagram of anti-collision access provided by the embodiments of the present application;

[0048] Figure 6 A schematic diagram of frequency modulation provided by the embodiments of the present application;

[0049] Figure 7 A communication method flow diagram provided for an embodiment of the present application;

[0050] Figure 8 A downlink TDD frame structure diagram provided for an embodiment of the present application;

[0051] Figure 9 Another downlink TDD frame structure diagram provided for an embodiment of the present application;

[0052] Figure 10 A downlink TDD and FDD multiplex frame structure diagram provided for an embodiment of the present application;

[0053] Figure 11 A signal transmission diagram of an amplitude modulation mode provided for an embodiment of the present application;

[0054] Figure 12 A diagram of transmitting an uplink reflection signal provided for an embodiment of the present application;

[0055] Figure 13 A diagram of querying access provided for an embodiment of the present application;

[0056] Figure 14 A communication device structure diagram provided for an embodiment of the present application. DETAILED DESCRIPTION

[0057] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0058] The embodiments of the present application can be applied to various mobile communication systems, for example: new radio (NR) system, long term evolution (LTE) system, advanced long term evolution (LTE-A) system, universal mobile communication system (UMTS), evolved long term evolution (eLTE) system, future communication system and other communication systems, and the specific embodiments are not limited herein.

[0059] To facilitate understanding of the embodiments of the present application, first take the communication system shown in Figure 1 as an example to describe in detail the communication system applicable to the embodiments of the present application. Figure 1 A communication system architecture diagram applicable to an embodiment of the present application.

[0060] As Figure 1As shown, the communication system comprises a first node 101, a tag node 102 and a second node 103.

[0061] The first node 101 can be a relay node (commonly referred to as Helper or Relay), and the first node 101 can also be referred to as a transmitter, a helper, an interrogator, a reader, a user equipment (UE), etc. for the convenience of description, which is referred to as the first node in the embodiments of the present application.

[0062] In the embodiments of the present application, the device for implementing the function of the first node can be the first node, or a device capable of supporting the first node to implement the function, such as a chip system, which can be installed in the first node. In the embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In the technical solutions provided in the embodiments of the present application, the device for implementing the function of the first node is taken as an example of the first node to describe the technical solutions provided in the embodiments of the present application.

[0063] Correspondingly, the tag node 102 can also be referred to as a tag node, a backscatter device, a passive device, a semi-passive device, an ambient signal device, a radio frequency identification (RFID) tag node, etc. for the convenience of description, which is referred to as the tag node in the embodiments of the present application.

[0064] In the embodiments of the present application, the device for implementing the function of the tag node can be the tag node, or a device capable of supporting the tag node to implement the function, such as a chip system, which can be installed in the tag node. In the embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In the technical solutions provided in the embodiments of the present application, the device for implementing the function of the tag node is taken as an example of the tag node to describe the technical solutions provided in the embodiments of the present application.

[0065] The second node 103 can also be referred to as a receiver, an access point, a base station, etc. for the convenience of description, which is referred to as the second node in the embodiments of the present application.

[0066] In the embodiments of the present application, the apparatus for implementing the function of the second node can be the second node, or can be an apparatus capable of supporting the second node to implement the function, such as a chip system, which can be installed in the second node. In the embodiments of the present application, the chip system can be composed of a chip, or can include the chip and other discrete devices. In the technical solutions provided by the embodiments of the present application, the apparatus for implementing the function of the second node is taken as an example of the second node to describe the technical solutions provided by the embodiments of the present application.

[0067] In Figure 1 , the first node 101 (such as a Helper) receives the indication of the second node 103 (such as a base station), and then sends a downlink excitation signal to the tag node 102, where the communication between the first node 101 and the second node 103 is the communication between traditional active devices. The downlink excitation signal can carry information sent to the second node 103, or can not carry information sent to the second node 103. The downlink excitation signal sent by the first node 101 is a signal known to the tag node 102. There can be at least one gap in the duration of the downlink excitation signal, which can be periodic or non-periodic.

[0068] After receiving the downlink excitation signal, the tag node 102 can modulate the information to be sent onto the downlink excitation signal, obtain an uplink reflection signal, and send the uplink reflection signal to the second node 103. In the embodiments of the present application, the tag node 102 can be a passive device, that is, it does not need to be powered during the process of receiving the downlink excitation signal and sending the uplink reflection signal, or the tag node 102 can be a semi-active device, that is, it needs to be powered during the process of receiving the downlink excitation signal or sending the uplink reflection signal.

[0069] It should be noted that in the communication system shown in Figure 1 , the second node 103 cannot directly send data to the tag node 102. If the second node 103 needs to send data to the tag node 102, it needs to first send the data to the first node 101, and then forward the data to the tag node 102 by the first node 101.

[0070] When the modulated backscatter communication is applied in a mobile communication system, such as 5G, the first node 101 can be a mobile phone, a Pad, a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The second node 103 can be a wireless access device, such as an evolved Node B (eNB), a gNB in 5G, a radio network controller (RNC) or a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (such as a home evolved NodeB or a home Node B, HNB), a baseband unit (BBU), an access point (AP) in a wireless fidelity (WiFi) system, a wireless relay node, a wireless backhaul node, etc.

[0071] It should be noted that, Figure 1 For example, in a possible implementation, the first node 101 and the second node 103 can also be integrated into the same physical entity, such as, Figure 2 Another architecture of a communication system to which embodiments of the present application are applicable.

[0072] As Figure 2 shown, the communication system includes a network node 201 and a tag node 202, wherein the network node 201 can be regarded as an integrated physical entity of the first node 101 and the second node 103 in the above-mentioned communication system. Figure 1

[0073] The network node 201 sends a downlink excitation signal to the tag node 202. After receiving the downlink excitation signal, the tag node 202 can modulate information to be transmitted onto the downlink excitation signal to obtain an uplink reflection signal, and send the uplink reflection signal to the network node 201.​

[0074] For the convenience of description, the following embodiments are described by taking the architecture of the communication system shown in Figure 1 as an example.

[0075] To facilitate understanding of the embodiments of the present application, the following first introduces some terms in the embodiments of the present application.

[0076] (1) Modulated Backscatter is a technology suitable for low cost and low power systems. Unlike traditional communication technology, the Modulated Backscatter transmitter itself does not generate and send RF (radio frequency) signals, but transmits information by modulating the RF signals in the environment, including wireless television signals, broadcast signals, signals sent by mobile communication stations, signals sent by routers (WiFi AP), signals sent by special card readers, etc.

[0077] The backscatter device transmits signals by controlling the impedance of the transmitting antenna. Taking the simplest OOK (On-Off Keying, binary on-off keying) as an example, assuming that the received signal is x, the reflected (transmitted) signal is y, and the relationship between the two can be expressed as: y = Γx, where Γ is the reflection coefficient, which can be expressed as: where Z a is the impedance of the antenna, generally 50 ohms. Z i is the matching impedance when the i-th state.

[0078] Based on the above assumptions, the '0' and '1' signals are transmitted as follows: when transmitting '0', select Z i = Z a * , the reflection coefficient Γ = 0, the energy of the RF signal is absorbed, at this time no signal is transmitted, at this time represents the OFF state. When transmitting '1', select Z i ≠ Z a * , the reflection coefficient Γ ≠ 0, the energy of the RF signal is reflected, at this time the signal is transmitted, at this time represents the ON state.

[0079] (2) Downlink excitation signal, obtained by modulating the information sent by the first node 101 to the tag node 102 on the downlink carrier signal. Please refer to Figure 3 , a downlink excitation signal diagram provided by the embodiments of the present application, as Figure 3As shown, the downlink carrier signal sent by the first node 101 is c(t), the downlink information is s(t), and the signal sent is x(t) = c(t) * s(t). Taking binary on-off keying (OOK) modulation as an example, the downlink carrier signal sent by the first node 101 is a sine wave, and the information [1 0 1] sent is carried.

[0080] (3) The uplink reflection signal is obtained by modulating the uplink information to be fed back to the downlink excitation signal received by the tag node 102.

[0081] Since the tag node itself does not contain a radio frequency link and cannot actively send information, it can only send the downlink excitation signal sent by the first node 101, and the tag node sends '1' or '0' information by changing the matching state of the antenna. Please refer to Figure 4 , another downlink excitation signal diagram provided by the embodiment of the application is shown in Figure 4 As shown, the downlink excitation signal sent by the base station is c(t), and the information sent by the tag is s(t), where 'On' indicates that the antenna is in a reflection state, and 'Off' indicates that the antenna is in an absorption state. The tag sends s(t) by changing the matching state of the antenna (On state indicates 1, and Off state indicates 0), and the uplink reflection signal sent by the tag node is x(t) = c(t) * s(t).

[0082] (4) Anti-collision access mode

[0083] In the conventional modulation backscatter communication, the random access of the tag node is realized based on an anti-collision protocol, and the architecture is shown in Figure 2 As an example, the network node is a base station, and there are three tag nodes in the signal coverage range of the base station, which are Tag1, Tag2, and Tag3. The access process of the three tag nodes to the cell under the base station is as follows:

[0084] Please refer to Figure 5 , an anti-collision access diagram provided by the embodiment of the application is shown in Figure 5 As shown, the base station sends a Query instruction to each tag node, requiring the tag to report its own identification (ID) or other information, and the tag nodes (Tag) 1, Tag2, and Tag3 simultaneously feed back response messages (QueryRsp), resulting in collision and access failure. The QueryRsp is used to respond to the Query instruction.

[0085] The base station sends a Query instruction to each tag node again. Tag 1, Tag 2 and Tag 3 find that the access fails, and each generates a random number: if '1', the access process continues, and a QueryRsp is sent; if '0', the access is abandoned, and no QueryRsp is sent. For example, Tag 2 abandons the access, and no QueryRsp is fed back, and Tag 1 and Tag 3 both feed back QueryRsp, resulting in collision and access failure.

[0086] The base station sends a Query instruction to each tag node again. Tag 1, Tag 2 and Tag 3 find that the access fails, and each generates a random number: if '1', the access process continues, and a QueryRsp is sent; if '0', the access is abandoned, and no QueryRsp is sent. For example, Tag 2 abandons the access, and no QueryRsp is fed back, and Tag 1 and Tag 3 both feed back QueryRsp, resulting in collision and access failure.

[0087] It should be noted that when only one tag node sends QueryRsp, the successful access of one tag node is completed, and the base station feeds back QueryAck, which contains the ID of the successfully accessed tag.

[0088] (5) Frequency shift keying (FSK)

[0089] In the conventional modulated backscatter communication, the tag adjusts the impedance matching state of the antenna, reflects or absorbs the downlink excitation signal, thereby realizing the function of sending '0' or '1'. The conventional modulated backscatter communication is different from the conventional communication, that is, the modulated backscatter communication has the problem of self-interference of the downlink excitation signal to the uplink reflected signal. Figure 1 As shown in the architecture, the first node is a Helper, and the second node is a base station. The Helper sends a downlink excitation signal for the tag node to reflect, that is, when the tag node reflects to generate an uplink reflected signal, the downlink excitation signal is always being sent. When the base station receives the uplink reflected signal reflected by the tag node, the downlink excitation signal sent by the Helper is also received at the same time, and the reception of the downlink excitation signal to the uplink reflected signal causes interference.

[0090] For example, the signal received by the base station is y = Γx + x, where x is the sent downlink excitation signal, and Γx is the uplink reflected signal reflected by the tag node. Since the energy of the wireless signal sharply decreases after reflection, the energy of Γx is much smaller than that of x, that is, |Γx| << |x|. 2 <<|x| 2In other words, the presence or absence of Γx has little impact on y, making it difficult for the base station to correctly demodulate Γx. There are generally two solutions to this problem: one is to use complex self-interference cancellation techniques at the base station to eliminate the interference of the downlink excitation signal x on Γx, but this leads to high implementation complexity and cost at the base station; the other is for the tag to use FSK (Frequency-Sensing Kinematics) to reflect the downlink excitation signal, thereby eliminating the interference of the downlink excitation signal on the uplink reflected signal at the base station through frequency domain filtering techniques. The implementation principle of FSK is as follows:

[0091] Please see Figure 6 This is a frequency modulation diagram provided in an embodiment of this application, such as... Figure 6 As shown, when the signal sent by the tag node is '1', the matching state of the antenna is switched back and forth between On and Off. The length of time occupied when sending '1' and the switching frequency of On / Off are specified by the standard implementation. The corresponding rate is defined as v = 1 / T, where T is the time occupied by On or Off.

[0092] When the tag node sends a signal of '0', the antenna is always in the Off state. At this time, the time taken to send signal '0' is the same as the time taken to send signal '1'.

[0093] The base station receives signals (including uplink reflected signals from tag nodes and downlink excitation signals sent by Helpers) and transforms them into the frequency domain: First, the base station's receiver performs frequency domain filtering to eliminate the downlink excitation signal at a specific frequency, where the frequency of the downlink excitation signal is f0; second, it detects the distance to the downlink excitation signal frequency. The signal strength is detected at f = f0 ± ΔF. If it exceeds a given threshold, the tag node reflection is determined to be 1; otherwise, it is 0. The specific value of the threshold is determined by the receiver's algorithm and is not specified here.

[0094] (6) "At least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after it are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0095] And, unless otherwise indicated, the ordinal numbers "first", "second", and the like in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, time sequence, priority, or importance of the multiple objects.

[0096] The network architecture and service scenarios described in the embodiments of the present application are used to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that, with the evolution of network architecture and the appearance of new service scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0097] To solve the problems mentioned in the background, based on Figure 1 The architecture of the communication system is shown in FIG. 1, please refer to Figure 7 A flowchart of a communication method is provided in the embodiments of the present application. The method can be executed by the first node or a component (such as a chip, circuit, etc.) for the first node at the first node side; can be executed by the tag node or a component (such as a chip, circuit, etc.) for the tag node at the tag node side; and can be executed by the second node or a component (such as a chip, circuit, etc.) for the second node at the second node side. For the convenience of illustration, the first node, the tag node, and the first node executing the method are taken as examples for illustration below.

[0098] As shown in Figure 7 The method includes the following steps:

[0099] Step 701, the first node generates a downlink excitation signal carrying first information and N downlink instructions.

[0100] The first information includes M uplink rates supported by this query, and the number of groups of tag nodes supported by each of the M uplink rates, and each of the N downlink instructions carries a target group identifier. The downlink instruction is used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal. M and N are both integers greater than 1.

[0101] For example, taking M equal to 2 as an example, that is, 2 uplink rates v1 and v2 are supported by this query, wherein v1 supports a group of tag nodes, and v2 supports two groups of tag nodes. The first information includes v1, v2, and the number of groups of tag nodes supported by v1 is 1, and the number of groups of tag nodes supported by v2 is 2.

[0102] To illustrate the relationship between the various uplink rates among the M uplink rates, taking the first uplink rate and the second uplink rate as examples, if the first uplink rate supports one set of tag nodes and the second uplink rate supports n sets of tag nodes, then the second uplink rate is greater than or equal to n times the first uplink rate. Here, the first uplink rate is any one of the M uplink rates, and the second uplink rate is any one of the M uplink rates other than the first uplink rate.

[0103] Downlink commands can be either query commands or non-query commands. Query commands specify the content that the tag node corresponding to the target group identifier carried in the query command needs to respond to. After receiving a non-query command, the tag node sends an uplink reflection signal according to the specific content to be responded to as indicated in the query command. Non-query commands do not specify the specific content that the tag node needs to respond to; after receiving a non-query command, the tag node can decide the content to respond to independently.

[0104] In some other embodiments, the downlink excitation signal may also carry a charging bit, which is used to instruct the tag node that receives the first information to select the uplink rate for transmitting the uplink reflected signal. The tag node that receives the first information may select the uplink rate for transmitting the uplink reflected signal within the duration occupied by the charging bit.

[0105] Step 702: The first node sends downlink excitation signals to the N groups of tag nodes within its signal coverage area.

[0106] Assuming the minimum rate supported by the modulated backscatter system is v0, and the downlink rate supported by each of the N groups of tag nodes is v m , where v m = f * v0, where m and f are both integers greater than 1. That is, the first node can have a downlink speed of v. m Send downlink excitation signals to N groups of tag nodes. The first node can send downlink excitation signals to N groups of tag nodes at the same downlink rate or at different downlink rates.

[0107] In this application embodiment, there are multiple ways to implement step 702. Two possible implementation methods are provided below.

[0108] In the first implementation method, the first node can send downlink excitation signals to N groups of tag nodes using time division duplex (TDD) frames.

[0109] Here, the TDD frame includes first information and N downlink instructions, wherein the N downlink instructions included in the TDD frame are transmitted in TDD mode.

[0110] In some other embodiments, the TDD frame can further comprise a charging bit. For example, the charging bit is located after the first information and before the N downlink instructions in the TDD frame, and the time length occupied by the charging bit is used to indicate the uplink rate of the tag nodes to send the uplink reflected signal. The first node can give the tag nodes in each group sufficient time to select the uplink rate by sending the charging bit.

[0111] Taking an example of N equal to 3 and the downlink rate v0, i.e., in the modulated backscatter system, all the tag nodes in the signal coverage range of the first node are divided into three groups, i.e., Group 1, Group 2 and Group 3, and each group of tag nodes comprises at least one tag node. The first node can transmit 3 downlink instructions to the three groups of tag nodes at the downlink rate v0 by using the TDD frame. The following exemplary shows two downlink TDD frame structures comprising different downlink instructions.

[0112] In one example, the downlink instruction is a Query instruction, please refer to Figure 8 , which is a downlink TDD frame structure provided by the embodiment of the present application.

[0113] As shown in Figure 8 , the downlink TDD frame structure comprises a header information (Header 0) (i.e., the first information in the above), a charging bit and three Query instructions, and the first node sequentially sends the Header 0, the charging bit and the three Query instructions in order, the three Query instructions are sent in the TDD mode, and the Header 0 and the three Query instructions are all sent at the lowest rate v0. The Header 0 comprises M uplink rates supported by this query and the number of groups of tag nodes supported by each of the M uplink rates. The time length occupied by the charging bit is used for the tag nodes to select the group and receive data at the appropriate rate according to the indication of the Header 0 and the signal strength of the received downlink excitation signal, and the Query instruction is used to schedule the tag nodes to enter the query state.

[0114] In another example, the downlink instruction is a non-Query instruction, please refer to Figure 9 , which is another downlink TDD frame structure provided by the embodiment of the present application.

[0115] As shown in Figure 9 , the downlink TDD frame structure comprises a header information (Header 0) (i.e., the first information in the above), a charging bit and three non-Query instructions, and the three non-Query instructions are sent in the TDD mode. The non-Query instruction can be a downlink information (Info) as shown in Figure 9 .

[0116] Header0 is used to indicate the number of subframes in the downlink frame, the uplink rate corresponding to each subframe, and the downlink rate of each subsequent subframe. Each subframe can be received at the downlink rate indicated in the initial Query instruction. For example, the bit information in Header0 can be as shown in Table 1.

[0117] Table 1 Bit information in Header0

[0118]

[0119]

[0120] The length of the charging bit is used for the tag node to select a group and receive data at a suitable rate according to the indication of Header0 and the signal strength of the received downlink excitation signal. Since each group of tag nodes in the three groups of tag nodes independently performs anti-collision access, the length of each subframe is different, and the length of the current subframe should be indicated in each subframe.

[0121] In a second implementation, the first node can send a downlink excitation signal to N groups of tag nodes using a TDD and frequency division duplexing (FDD) multiplex frame.

[0122] Here, the TDD and FDD multiplex frame can include first information and N downlink instructions. In the N downlink instructions included in the TDD and FDD multiplex frame, each downlink instruction transmitted at the same downlink rate is transmitted in a TDD manner, and each downlink instruction transmitted at a different downlink rate is transmitted in an FDD manner.

[0123] In other embodiments, the TDD frame can also include a charging bit. For example, the charging bit is located after the first information and before the N downlink instructions in the TDD frame. The length of the charging bit is used for the tag node to select the uplink rate at which the uplink reflection signal is transmitted.

[0124] Taking an example in which the first node transmits a downlink excitation signal to three groups of tag nodes at different rates, i.e., N is equal to 3, the modulation backscatter system includes three groups of tag nodes, namely Group1, Group2, and Group3, and the following exemplary shows a downlink TDD and FDD multiplex frame structure including a Query instruction.

[0125] Please refer to Figure 10 , which is a downlink TDD and FDD multiplex frame structure provided by the embodiment of the present application.

[0126] As Figure 10As shown, the downlink TDD and FDD multiplex frame structure includes header information (Header 0) (i.e., the first information in the above), a charging bit, and three Query instructions, and the first node sequentially sends the Header 0, the charging bit, and the three Query instructions in sequence, and the three Query instructions are sent in a TDD and FDD multiplex manner.

[0127] The first node sends the Header 0 at the lowest rate v0, and since the tag nodes in Group 1 and the tag nodes in Group 2 are closer to the first node, and the tag nodes in Group 3 are farther away from the first node, the first node sends the Query instructions to Group 1 and Group 2 at a downlink rate v2, and sends the Query instructions to Group 3 at a downlink rate v1, where v2 is greater than or equal to 2v1. The Header 0 includes M uplink rates supported in this query, and the number of groups of tag nodes supported by each of the M uplink rates. The charging bit occupies a time length for the tag nodes to select a group and receive data at a suitable rate according to the indication of the Header 0 and the signal strength of the received downlink excitation signal. The Query instruction is used to schedule the tag nodes to enter the query state.

[0128] In this second implementation manner, the first node sends the downlink excitation signal to the N groups of tag nodes in a TDD and FDD multiplex frame, which can improve the transmission efficiency compared with sending the downlink excitation signal in a TDD frame in the first implementation manner.

[0129] In a possible implementation manner, the downlink excitation signal can be modulated in an amplitude shift keying (ASK) manner. Correspondingly, the requirement for the tag nodes is higher, and the tag nodes are required to be able to demodulate 4ASK.

[0130] In a possible implementation manner, the first node sends the downlink excitation signal in the above Figure 10 Taking the downlink TDD and FDD multiplex frame structure as an example, assuming that v2 is equal to 2v1, an example of sending a signal in an amplitude modulation manner is shown below.

[0131] Please refer to Figure 11 A schematic diagram of sending a signal in an amplitude modulation manner provided by the embodiment of the application.

[0132] As Figure 11As shown, assuming that the signal that the first node needs to send to Group 1 and Group 2 is x, wherein x1 is the Query instruction sent by Group 1, and x2 is the Query instruction sent by Group 2, the signal that the first node needs to send to Group 3 is y, wherein interference will occur between (x1+x2) and y, and due to the limitation of the capability of the tag node itself, the tag node cannot eliminate the interference between x and y in the FDD manner as the base station (such as the first node or the second node), therefore, in order to avoid the problem, the first node can send x and y in the following manner:

[0133] It is assumed that the signal sent by the first node to the tag node adopts the non-return-to-zero code design, that is, the jump from high to low represents 1, and the jump from low to high represents 0.

[0134] The first node sends x and y in the 4ASK manner, wherein x is the series connection of x1 and x2, and the signal z sent by the first node is the product of x and y, that is, z=x*y. Assuming that x1, x2 and y all send the same bit information, wherein x1 and x2 adopt the amplitude modulation of (1, 2), and y adopts the amplitude modulation of (1, 4), the amplitude of the output z includes (8, 4, 2, 1), wherein 1 represents the lowest amplitude after normalization and is not 0.

[0135] After that, for the tag node that adopts v2 to receive the access of Group 1 and Group 2, the received signal is (8, 4) and (2, 1), and for the tag node that adopts v1 to receive the access of Group 3, the received signal is (8, 4), (1, 2), (1, 2), (4, 8).

[0136] In addition, the first node also sends the charging bit in the 4ASK manner similar to Figure 11 In the 4ASK manner in the charging bit, the charging bit is used not only for charging but also for the receiving circuit of the tag node to obtain the comparison threshold of 4ASK.

[0137] In this example, the first node sends the signal carrying the Query instruction to each group of tag nodes in the ASK manner, and each group of tag nodes can demodulate the Query instruction sent to itself in the 4ASK manner after receiving the signal without interference from the signals received by other groups.

[0138] In the modulation reflection communication system, after the first node sends the downlink excitation signal to the N groups of tag nodes, any tag node in the N groups of tag nodes that receives the downlink excitation signal can process it in the following steps 703 to 705, which are described below by taking the first tag node as an example.

[0139] Step 703, the first tag node receives the downlink excitation signal from the first node. Here, the first tag node is any tag node in the N groups of tag nodes in the modulated reflection communication system.

[0140] Corresponding to the first implementation manner of step 702, one manner of implementing step 703 is that the first tag node can receive the downlink excitation signal sent by the first node in a TDD frame. The N downlink instructions included in the TDD frame are transmitted in a TDD manner. For details of the TDD frame, refer to the description of the TDD frame above, which will not be repeated here.

[0141] Corresponding to the second implementation manner of step 702, another manner of implementing step 703 is that the first tag node can receive the downlink excitation signal sent by the first node in a TDD and FDD multiplexing frame. In the N downlink instructions included in the TDD and FDD multiplexing frame, each downlink instruction sent at the same downlink rate is transmitted in a TDD manner, and each downlink instruction sent at a different downlink rate is transmitted in an FDD manner. For details of the TDD and FDD multiplexing frame, refer to the description of the TDD and FDD multiplexing frame above, which will not be repeated here.

[0142] Step 704, when the group identity of the first tag node is the same as the target group identity carried in one of the N downlink instructions, the first tag node selects an uplink rate from the M uplink rates according to the group identity of the first tag node, the first information, and the signal strength of the received downlink excitation signal.

[0143] When selecting the uplink rate, the first tag node can select an uplink rate from the M uplink rates included in the first information according to the signal strength of the received downlink excitation signal. For each tag node, the greater the signal strength of the received downlink excitation signal, the closer the distance between the tag node and the first node, and the higher the uplink rate that can be selected. The smaller the signal strength of the received downlink excitation signal, the farther the distance between the tag node and the first node, and the lower the uplink rate that can be selected.

[0144] In the embodiments of the present application, the uplink rates selected by different groups can be the same or different. Taking the case where the current query supports two uplink rates v1 and v2 as an example, the uplink rate v1 supports one group of tag nodes, and the uplink rate v2 supports two groups of tag nodes. The three groups of tag nodes are Group1, Group2, and Group3. The two groups of tag nodes Group1 and Group2 select the same uplink rate v2, and the one group of tag nodes Group3 selects the uplink rate v1.

[0145] Step 705, the first tag node sends an uplink reflection signal to the second node using the selected uplink rate.

[0146] The uplink reflection signal carries a response message for the downlink instruction.

[0147] In a possible implementation, if the selected uplink rate is selected by the second label node, the first label node and the second label node transmit the uplink reflection signal in a time division duplex (TDD) mode at the selected uplink rate; or the first label node transmits the uplink reflection signal in a frequency division duplex (FDD) mode at the selected uplink rate and the second label node transmits the uplink reflection signal in the FDD mode at another uplink rate selected from the M uplink rates.

[0148] For each group of label nodes selecting the same uplink rate, for example, Group 1 and Group 2 select the same uplink rate v2, Group 1 and Group 2 transmit the uplink reflection signal in a TDD mode. Each group of label nodes selecting different uplink rates transmits the uplink reflection signal in an FDD mode, for example, Group 3 selects the uplink rate v1, and Group 3 transmits the uplink reflection signal in the FDD mode with Group 1 and Group 2. A specific example is provided below.

[0149] Referring to Figure 12 , a schematic diagram of transmitting an uplink reflection signal is provided for the embodiments of the present application.

[0150] As shown in Figure 12 , taking a first node as a base station as an example, the label nodes in the modulation reflection communication system are divided into three groups, namely, Group 1, Group 2, and Group 3.

[0151] The base station transmits three Query instructions, and after the three groups of label nodes receive the three Query instructions, the label nodes determine the Query instruction sent to themselves according to their own identities and the target group identity carried by each Query instruction. Then, each group of label nodes selects an uplink rate for transmitting an uplink reflection signal, and the label nodes in Group 1, Group 2, and Group 3 simultaneously feed back a response message QueryRsp, for example, Group 1 and Group 2 select the rate v2, and Group 3 selects the rate v1, wherein the rate v2 is at least twice the rate v1. According to the relationship between the rates of Group 1, Group 2, and Group 3, the label nodes in Group 3 complete the transmission of one response message at the same time as the label nodes in Group 1 and Group 2 each complete the transmission of one response message.

[0152] In this example, the label nodes in Group 1, Group 2, and Group 3 all transmit the uplink reflection signal in the FSK mode, and each group of label nodes independently implements anti-collision access.

[0153] At step 706, the second node receives the uplink reflection signals from the N groups of tag nodes within a preset time length.

[0154] In a possible implementation, the second node receives the uplink reflection signals sent by the tag nodes of each group in a time division duplex (TDD) manner at the first uplink rate and receives the uplink reflection signals sent by the tag nodes of each group in a time division duplex (TDD) manner at the second uplink rate within the preset time length. The uplink reflection signals sent by the tag nodes of each group at the first uplink rate and the uplink reflection signals sent by the tag nodes of each group at the second uplink rate are sent in a frequency division duplex (FDD) manner.

[0155] At step 707, the second node demodulates the uplink reflection signals to obtain the response information fed back by the tag nodes of each group.

[0156] In a possible implementation, for the i th uplink rate in the M uplink rates, i is a positive integer, the following is performed: if the i th uplink rate corresponds to one group of tag nodes, frequency filtering processing is performed on the uplink reflection signals received within the preset time length to filter out other uplink reflection signals except the frequency corresponding to the i th uplink rate, and the uplink reflection signals after the frequency filtering processing are demodulated in a frequency shift keying (FSK) manner to obtain the response message sent by the tag nodes of the group corresponding to the i th uplink rate; if the i th uplink rate corresponds to q groups of tag nodes, q is an integer greater than 1, the preset time length is equally divided into q time periods, frequency filtering processing is performed on the uplink reflection signals received in each time period to filter out other uplink reflection signals except the frequency corresponding to the i th uplink rate, and the uplink reflection signals after the frequency filtering processing are demodulated in a frequency shift keying (FSK) manner to obtain the response message sent by the tag nodes of each group corresponding to the i th uplink rate.

[0157] In the example of the prior art, the second node is a base station, the preset time length is T1+T2, frequency domain filtering is performed on the signals received by the base station within T1+T2 to eliminate the interference of the downlink excitation signal with the frequency f0 and other group signals with the frequency f2=f0+ΔF2 on the reception, and then the response message fed back by the tag nodes in Group 3 is obtained in an FSK demodulation manner. Figure 12

[0158] ​In addition to the uplink reflection signals reflected by the tag nodes in each group, the base station can also receive the downlink excitation signal sent by the first node. Taking the case where the signal received by the base station includes the uplink reflection signals reflected by the tag nodes in each group and the downlink excitation signal as an example, the base station performs frequency domain filtering on the signal received in T1 time, eliminates the downlink excitation signal with the frequency point f0 and the signal with the frequency point f1 = f0 + ΔF1 from other groups, which interferes with the reception, and then obtains the response message fed back by the tag nodes in Group 1 according to the FSK demodulation mode.

[0159] The base station performs frequency domain filtering on the signal received in T2 time, eliminates the downlink excitation signal with the frequency point f0 and the signal with the frequency point f1 = f0 + ΔF1 from other groups, which interferes with the reception, and then obtains the response message fed back by the tag nodes in Group 2 according to the FSK demodulation mode.

[0160] Through the example, the response message fed back by the tag nodes in each group can be obtained respectively.

[0161] In step 708, the second node determines the tag nodes accessible in this query according to the response information fed back by the tag nodes in each group.

[0162] In step 709, the second node sends a confirmation access message to the accessible tag nodes, and the confirmation access message carries the identification of the accessible tag nodes.

[0163] In the embodiment of the application, the first node sends the downlink instruction in groups, and the N groups of tag nodes send the reflection signals at different uplink rates after receiving the downlink instruction, so that the reflection signals can be sent at reasonable rates, thereby improving the access efficiency.

[0164] A specific example is provided below to illustrate the query and access process of the application.

[0165] Taking the case where the first node and the second node are integrated in one device, for example, a base station, please refer to Figure 13 , which is a schematic diagram of the query and access provided in the embodiment of the application. As shown in Figure 13 , there are three groups of tag nodes in the signal coverage range of the base station, which are Group 1, Group 2 and Group 3. Group 1 includes two tag nodes, Tag 1 and Tag 2, Group 2 includes two tag nodes, Tag 3 and Tag 4, and Group 3 includes one tag node, Tag 5.

[0166] Firstly, the base station sends three Query instructions, the three Query instructions can be sent by using TDD frame, or can be sent by using TDD and FDD multiplex frame, after three groups of tag nodes receive the three Query instructions, according to the self-identity and the target group identity carried by each Query instruction, the Query instruction sent to itself is determined. Then, each group of tag nodes selects the uplink rate of sending the uplink reflection signal, for example, the rate selected by Group 1 and Group 2 is v2, the rate selected by Group 3 is v1, wherein the rate of v2 is at least twice more than v1. Group 1 and Group 2 feed back the response message QueryRsp by using TDD mode, at the same time, the tag nodes in Group 3 feed back the response message QueryRsp by using TDD mode with Group 1 and Group 2, that is, the tag nodes in Group 3 complete the transmission of one response message at the same time, and Group 1 and Group 2 also complete the transmission of one response message respectively.

[0167] After the base station receives the signal carrying the response messages fed back by the three groups of tag nodes, the signal is processed by frequency filtering by using the filtering mode in the example shown in the figure, and the response message of Group 1, the response message of Group 2 and the response message of Group 3 can be demodulated. Since the response messages fed back by the two tag nodes in Group 1 collide and access fails, and the response messages fed back by the two tag nodes in Group 2 collide and access fails, only Tag 5 in Group 3 accesses successfully. Figure 12

[0168] The base station sends the QueryAck instruction (i.e. the confirmation access message in the above) to Tag 5 in Group 3, and the QueryAck instruction can also be referred to as Ack, and then sends two Query instructions.

[0169] The tag nodes in Group 1 and Group 2 receive the Query instruction sent to themselves respectively, Tag 1 and Tag 2 in Group 1 find that the access fails, Tag 2 gives up this access, and Tag 1 feeds back QueryRsp, Tag 3 and Tag 4 in Group 2 find that the access fails, Tag 3 gives up this access, and Tag 4 feeds back QueryRsp.

[0170] The base station sends the Ack instruction to Tag 1 to respond to the successful access of Tag 1. The base station sends the Ack instruction to Tag 4 to respond to the successful access of Tag 4.

[0171] ​The base station sends three Query instructions again. After Tag 2 receives the Query instruction sent to itself, it feeds back a Query Rsp. After Tag 3 receives the Query instruction sent to itself, it feeds back a Query Rsp.

[0172] Then, the base station sends an Ack instruction to Tag 2 and Tag 3 respectively to respond to the successful access of Tag 2 and Tag 3.

[0173] In the embodiments of the present application, different groups of tags adopt different uplink rates, and the FDD and TDD multiplexing modes are used to transmit the uplink reflection signals, which can effectively improve the system efficiency.

[0174] The above mainly introduces the scheme provided by the embodiments of the present application from the perspective of the interaction between various network elements. It can be understood that the above implementation of each network element includes the hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiments disclosed in the present text, the present application can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0175] It can be understood that, in each of the above method embodiments, the steps or operations implemented by the first node can also be implemented by a component (such as a chip or circuit) configured in the first node, the steps or operations implemented by the tag node can also be implemented by a component (such as a chip or circuit) configured in the tag node, and the steps or operations implemented by the second node can also be implemented by a component (such as a chip or circuit) configured in the second node.

[0176] The embodiments of the present application also provide a device for implementing any one of the above methods, for example, a device is provided, which includes units (or means) for implementing each step performed by the first node in any one of the above methods. For another example, another device is provided, which includes units (or means) for implementing each step performed by the tag node in any one of the above methods. For another example, another device is provided, which includes units (or means) for implementing each step performed by the second node in any one of the above methods.

[0177] Please refer to Figure 14 Fig. 1 is a structural schematic diagram of a communication device provided by the embodiments of the present application. As shown in the figure, the device 1400 includes a processing unit 1401 and a transceiver unit 1402. Figure 14 The transceiver unit 1402 is configured to receive a signal from a network element or transmit a signal to a network element. The processing unit 1401 is configured to process the signal received by the transceiver unit 1402 or to be transmitted by the transceiver unit 1402.

[0178] When the apparatus is used to implement the steps performed by the first node in the above method embodiments:

[0179] The processing unit 1401 is configured to generate a downlink excitation signal carrying first information and N downlink instructions; wherein the first information includes M uplink rates supported by this query and the number of groups of tag nodes supported by each of the M uplink rates, and each downlink instruction carries a target group identifier, and the downlink instruction is used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal, and M and N are integers greater than 1.

[0180] The transceiver unit 1402 is configured to send the downlink excitation signal to the N groups of tag nodes within the signal coverage range of itself.

[0181] In a possible implementation, the transceiver unit 1402 is specifically configured to send the downlink excitation signal to the N groups of tag nodes using a TDD frame structure, and the TDD frame structure includes the first information and the N groups of downlink instructions transmitted in a TDD manner.

[0182] In a possible implementation, the transceiver unit 1402 is specifically configured to send the downlink excitation signal to the N groups of tag nodes using a time division duplex (TDD) frame, and the N downlink instructions included in the TDD frame are transmitted in a TDD manner.

[0183] In a possible implementation, the transceiver unit 1402 is specifically configured to send the downlink excitation signal to the N groups of tag nodes using a TDD and frequency division duplex (FDD) multiplex frame, and each of the N groups of downlink instructions included in the TDD and FDD multiplex frame is transmitted in a TDD manner or an FDD manner.

[0184] In a possible implementation, the downlink excitation signal is obtained by modulating in an amplitude modulation manner.

[0185] In a possible implementation, the downlink excitation signal further carries a charging bit; and the charging bit is used to instruct a tag node receiving the first information to select an uplink rate for sending the uplink reflection signal.

[0186] In a possible implementation, if a first uplink rate supports one group of tag nodes and a second uplink rate supports n groups of tag nodes, the second uplink rate is greater than or equal to n times the first uplink rate; wherein the first uplink rate is any one of the M uplink rates, and the second uplink rate is any one of the M uplink rates except the first uplink rate.

[0187] In a possible implementation, the downlink instruction includes a Query instruction or a non-Query instruction.

[0188] When the apparatus is used to implement the steps performed by the corresponding first tag node in the method embodiments described above:

[0189] The transceiver 1402 is configured to receive a downlink excitation signal from the first node, the downlink excitation signal including first information and N downlink instructions; wherein the first information includes M uplink rates supported by this query and the number of groups of tag nodes supported by each of the M uplink rates, and each downlink instruction carries a target group identifier, the downlink instruction being used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal, M and N being integers greater than 1.

[0190] The processing unit 1401 is configured to, when the group identifier of the apparatus is the same as the target group identifier carried in one of the N downlink instructions, select an uplink rate from the M uplink rates according to the group identifier of the apparatus, the first information, and the signal strength at which the downlink excitation signal is received.

[0191] The transceiver 1402 is further configured to send an uplink reflection signal to the second node using the selected uplink rate.

[0192] In a possible implementation, the transceiver 1402 and the second tag node use the selected uplink rate to send the uplink reflection signal in a time division duplex (TDD) mode if the selected uplink rate is selected by the second tag node; or the transceiver 1402 uses the selected uplink rate, and the second tag node uses another uplink rate selected from the M uplink rates, to send the uplink reflection signal in a frequency division duplex (FDD) mode.

[0193] In a possible implementation, the transceiver 1402 is specifically configured to receive a downlink excitation signal sent by the first node in a TDD frame; and the N downlink instructions included in the TDD frame are transmitted in a TDD mode.

[0194] In a possible implementation, the transceiver 1402 is specifically configured to receive a downlink excitation signal sent by the first node in a TDD and FDD multiplexing frame; and in the N downlink instructions included in the TDD and FDD multiplexing frame, each downlink instruction sent at the same downlink rate is transmitted in a TDD mode, and each downlink instruction sent at a different downlink rate is transmitted in an FDD mode.

[0195] In a possible implementation, the downlink excitation signal is obtained by amplitude modulation.

[0196] In a possible implementation, the downlink incentive signal comprises a charging bit; the charging bit is used to indicate that the tag node receiving the first information selects an uplink rate for sending the uplink reflection signal.

[0197] In a possible implementation, if the first uplink rate supports a group of tag nodes and the second uplink rate supports n groups of tag nodes, the second uplink rate is greater than or equal to n times the first uplink rate; wherein the first uplink rate is any one of the M uplink rates, and the second uplink rate is any one of the M uplink rates except the first uplink rate.

[0198] In a possible implementation, the downlink instruction comprises a Query instruction or a non-Query instruction.

[0199] When the apparatus is used to implement each step performed by the second node in the method embodiments described above:

[0200] The transceiver 1402 is configured to receive, within a preset time length, uplink reflection signals from N groups of tag nodes; wherein an uplink rate used by each group of tag nodes when sending the uplink reflection signal is determined according to first information and a signal strength of a received downlink incentive signal; the first information comprises M uplink rates supported by this query and a group number of at least one group of tag nodes corresponding to each of the M uplink rates.

[0201] The processing unit 1401 is configured to demodulate the uplink reflection signal to obtain response information fed back by each group of tag nodes, and determine tag nodes that can be accessed in this query according to the response information fed back by each group of tag nodes.

[0202] The transceiver 1402 is further configured to send a confirmation access message to the accessible tag nodes, and the confirmation access message carries an identifier of the accessible tag nodes.

[0203] In a possible implementation, the transceiver 1402 is specifically configured to receive, within a preset time length, uplink reflection signals sent by each group of tag nodes in a time division duplex (TDD) manner using a first uplink rate, and receive uplink reflection signals sent by each group of tag nodes in a time division duplex (TDD) manner using a second uplink rate; wherein the uplink reflection signals sent by each group of tag nodes using the first uplink rate and the uplink reflection signals sent by each group of tag nodes using the second uplink rate are sent in a frequency division duplex (FDD) manner.

[0204] In a possible implementation, the processing unit 1401 is specifically configured to: for the i-th uplink rate in the M uplink rates, perform: if the i-th uplink rate corresponds to a group of tag nodes, performing frequency filtering processing on the received uplink reflection signals in a preset time length to filter out uplink reflection signals other than the frequency corresponding to the i-th uplink rate, and demodulating the uplink reflection signals after the frequency filtering processing in a frequency modulation FSK manner to obtain a response message sent by each tag node in the group of tag nodes corresponding to the i-th uplink rate; if the i-th uplink rate corresponds to q groups of tag nodes, q is an integer greater than 1, then equally dividing the preset time length into q time periods, performing frequency filtering processing on the uplink reflection signals received in each time period to filter out uplink reflection signals other than the frequency corresponding to the i-th uplink rate, and demodulating the uplink reflection signals after the frequency filtering processing in a frequency modulation FSK manner to obtain a response message sent by each group of tag nodes corresponding to the i-th uplink rate.

[0205] In a possible implementation, if the first uplink rate supports a group of tag nodes and the second uplink rate supports n groups of tag nodes, the second uplink rate is greater than or equal to n times the first uplink rate; wherein the first uplink rate is any one of the M uplink rates supported by the current query, and the second uplink rate is any one of the M uplink rates other than the first uplink rate.

[0206] It can be understood that each of the units described above can also be referred to as a module or a circuit, and each of the units can be independently set, or can be fully or partially integrated.

[0207] The transceiver unit 1402 described above can also be referred to as a communication interface, and the processing unit 1401 described above can also be referred to as a processor.

[0208] Optionally, the communication device 1400 can further include a storage unit, which is used to store data or instructions (also referred to as code or program). Each of the units can interact with or be coupled to the storage unit to implement corresponding methods or functions. For example, the processing unit can read data or instructions in the storage unit, so that the communication device implements the methods in the above embodiments.

[0209] It should be understood that the division of units in the above apparatus is only a logical functional division, and in actual implementation, all or part of the units can be integrated into one physical entity, or can be physically separated. The units in the apparatus can all be implemented in the form of software invoked by a processing element; or all be implemented in the form of hardware; or part of the units are implemented in the form of software invoked by a processing element, and part of the units are implemented in the form of hardware. For example, each unit can be a separately established processing element, or can be integrated in a chip of the apparatus, in addition, the unit can also be stored in the form of a program in a memory, and the function of the unit is invoked and executed by a processing element of the apparatus. In addition, all or part of the units can be integrated together, or can be independently implemented. The processing element described herein can be a processor, which can be an integrated circuit with a signal processing capability. In the implementation process, each step of the above method or each unit can be implemented by an integrated logic circuit of hardware in the processing element, or in the form of software invoked by the processing element.

[0210] In one example, the units in any of the above apparatuses can be one or more integrated circuits configured to implement the above method, for example, one or more application specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms. For another example, when the units in the apparatus can be implemented in the form of a program invoked by a processing element, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor that can invoke a program. For another example, the units can be integrated together to implement a system-on-a-chip (SOC).

[0211] The above unit for receiving (for example, the receiving unit) is an interface circuit of the apparatus for receiving signals from other apparatuses. For example, when the apparatus is implemented in the form of a chip, the receiving unit is an interface circuit of the chip for receiving signals from other chips or apparatuses. The above unit for sending (for example, the sending unit) is an interface circuit of the apparatus for sending signals to other apparatuses. For example, when the apparatus is implemented in the form of a chip, the sending unit is an interface circuit of the chip for sending signals to other chips or apparatuses.

[0212] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program. When the computer program is executed by a computer, the computer can implement the method on the first node side in the method embodiment.

[0213] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program. When the computer program is executed by a computer, the computer can implement the method on the first node side in the method embodiment.

[0214] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program. When the computer program is executed by a computer, the computer can implement the method on the first node side in the method embodiment.

[0215] The embodiment of the present application further provides a computer program product for storing a computer program. When the computer program is executed by a computer, the computer can implement the method on the first node side in the method embodiment.

[0216] The embodiment of the present application further provides a computer program product for storing a computer program. When the computer program is executed by a computer, the computer can implement the method on the first node side in the method embodiment.

[0217] The embodiment of the present application further provides a computer program product for storing a computer program. When the computer program is executed by a computer, the computer can implement the method on the first node side in the method embodiment.

[0218] It should be understood that the processor mentioned in the embodiment of the present application can be a CPU, and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0219] It should also be understood that the memory mentioned in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically EPROM (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM) used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM) and direct rambus RAM (DR RAM).

[0220] It should be noted that when the processor is a general processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) is integrated in the processor.

[0221] It should be noted that the memory described herein is intended to include, but not limited to, these and any other suitable types of memory.

[0222] It should be understood that in various embodiments of the present application, the size of the sequence number of each process described above does not mean the order of execution, the execution order of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0223] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0224] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0225] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the above-described device embodiments are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0226] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0227] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit.

[0228] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the parts of the prior art that make contributions or parts of the technical solutions can be embodied in the form of software products. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the embodiments of the present application. The aforementioned computer readable storage medium can be any available medium that can be accessed by a computer. For example, but not limited to: the computer readable medium can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), universal serial bus flash disk, mobile hard disk, or other optical disk storage, magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer.

[0229] The above is only a specific implementation of the present application, but the protection scope of the embodiments of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the embodiments of the present application, which should be covered within the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application should be subject to the protection scope of the claims.

Claims

1. A communication device, characterized by The communication device comprises: a processing unit configured to generate a downlink excitation signal carrying first information and N downlink instructions, wherein the first information comprises M uplink rates supported by this query and a number of groups of tag nodes supported by each of the M uplink rates, and each of the downlink instructions carries a target group identifier, and the downlink instruction is used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal, and M and N are integers greater than 1; a transceiver configured to send the downlink excitation signal to N groups of tag nodes within a signal coverage range of the communication device.

2. The communication apparatus according to claim 1, wherein The transceiver is specifically configured to: send the downlink excitation signal to the N groups of tag nodes by using a time division duplex (TDD) frame, and the N downlink instructions included in the TDD frame are transmitted in a TDD manner.

3. The communication apparatus according to claim 1, wherein The transceiver is specifically configured to: send the downlink excitation signal to the N groups of tag nodes by using a TDD and frequency division duplex (FDD) multiplex frame, and each of the N downlink instructions included in the TDD and FDD multiplex frame is transmitted in a TDD manner or an FDD manner.

4. The communication apparatus according to claim 3, wherein The downlink excitation signal is obtained by amplitude modulation.

5. The communication apparatus according to any one of claims 1-4, wherein, The downlink excitation signal further carries a charging bit. The charging bit is used to instruct a tag node receiving the first information to select an uplink rate for sending the uplink reflection signal.

6. A communication device, characterized by The communication device is any one of N groups of tag nodes in a modulated reflection communication system, and the communication device comprises: a transceiver configured to receive a downlink excitation signal from a first node, wherein the downlink excitation signal comprises first information and N downlink instructions, and the first information comprises M uplink rates supported by this query and a number of groups of tag nodes supported by each of the M uplink rates, and each of the downlink instructions carries a target group identifier, and the downlink instruction is used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal, and M and N are integers greater than 1; a processing unit configured to select an uplink rate from the M uplink rates according to a group identifier of the communication device, the first information, and a signal strength of the downlink excitation signal, when the group identifier of the communication device is the same as the target group identifier carried in one of the N downlink instructions. The transceiver is further configured to send the uplink reflection signal to a second node by using the selected uplink rate.

7. The communication apparatus according to claim 6, wherein The transceiver is specifically configured to: if the selected uplink rate is selected by a second tag node, the transceiver and the second tag node send the uplink reflection signal in a time division duplex (TDD) manner by using the selected uplink rate; or the transceiver sends the uplink reflection signal in a frequency division duplex (FDD) manner by using the selected uplink rate and a second tag node sends the uplink reflection signal in the FDD manner by using another uplink rate selected from the M uplink rates.

8. The communication apparatus according to claim 6 or 7, wherein, The transceiver is specifically configured to: The first node transmits a downlink excitation signal in a TDD frame; the TDD frame includes N downlink instructions transmitted in a TDD mode.

9. The communication apparatus according to claim 6 or 7, wherein The transceiver unit is specifically configured to: The first node transmits the downlink excitation signal in a TDD and FDD multiplexing frame; the N downlink instructions included in the TDD and FDD multiplexing frame are transmitted in a TDD mode if each downlink instruction is transmitted at a same downlink rate, and are transmitted in an FDD mode if each downlink instruction is transmitted at a different downlink rate.

10. The communication apparatus according to claim 6 or 7, wherein The downlink excitation signal includes a charging bit; The charging bit is used to instruct a tag node receiving the first information to select an uplink rate for transmitting the uplink reflection signal.

11. The communication apparatus according to claim 6 or 7, wherein If a first uplink rate supports a group of tag nodes and a second uplink rate supports n groups of tag nodes, the second uplink rate is greater than or equal to n times the first uplink rate; wherein the first uplink rate is any one of the M uplink rates, and the second uplink rate is any one of the M uplink rates except the first uplink rate.

12. A communications device, characterized by The transceiver unit is configured to: The transceiver unit is configured to receive uplink reflection signals from N groups of tag nodes within a preset time length; wherein an uplink rate used by each group of tag nodes for transmitting the uplink reflection signal is determined according to first information and a signal strength of a received downlink excitation signal; the first information includes M uplink rates supported by this query and a group number of at least one group of tag nodes corresponding to each of the M uplink rates; The processing unit is configured to demodulate the uplink reflection signals to obtain response information fed back by each group of tag nodes, and determine tag nodes accessible in this query according to the response information fed back by each group of tag nodes. The transceiver unit is further configured to transmit an access confirmation message to the accessible tag nodes, and the access confirmation message carries an identifier of the accessible tag nodes.

13. The communication apparatus according to claim 12, wherein The transceiver unit is specifically configured to: The transceiver unit is specifically configured to:

14. The communication apparatus according to claim 12 or 13, characterized in that, The processing unit is specifically configured to: If the ith uplink rate corresponds to a group of tag nodes, the transceiver unit performs frequency filtering processing on the uplink reflection signals received within the preset time length to filter out other uplink reflection signals except a frequency corresponding to the ith uplink rate, and demodulates the uplink reflection signals after the frequency filtering processing in a frequency modulation (FSK) mode to obtain a response message transmitted by the group of tag nodes corresponding to the ith uplink rate. ​ If the ith uplink rate corresponds to q groups of tag nodes, and q is an integer greater than 1, the preset time length is equally divided into q time periods, the uplink reflection signals received in each time period are subjected to frequency filtering processing to filter out other uplink reflection signals except the frequency corresponding to the ith uplink rate, and the uplink reflection signals subjected to frequency filtering processing are subjected to FSK demodulation to obtain the response messages sent by each group of tag nodes corresponding to the ith uplink rate.

15. A method of communication, comprising: Comprise: The first node generates a downlink excitation signal carrying first information and N downlink instructions; wherein the first information comprises M uplink rates supported by this query and the number of groups of tag nodes supported by each of the M uplink rates, and each of the downlink instructions carries a target group identifier, the downlink instruction is used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal, and M and N are integers greater than 1. The first node sends the downlink excitation signal to N groups of tag nodes within its own signal coverage range.

16. The communication method according to claim 15, wherein, The first node sends the downlink excitation signal to N groups of tag nodes within its own signal coverage range, comprising: The first node sends the downlink excitation signal to the N groups of tag nodes using time division duplex (TDD) frames, and the N downlink instructions included in the TDD frames are transmitted in a TDD manner.

17. The communication method of claim 15, wherein, The first node sends the downlink excitation signal to N groups of tag nodes within its own signal coverage range, comprising: The first node sends the downlink excitation signal to the N groups of tag nodes using TDD and frequency division duplex (FDD) multiplexed frames, and each of the N downlink instructions included in the TDD and FDD multiplexed frames is transmitted in a TDD manner or an FDD manner.

18. The communication method according to claim 17, wherein, The downlink excitation signal is obtained by amplitude modulation.

19. The communication method according to any one of claims 15-18, characterized by, The downlink excitation signal also carries a charging bit. The charging bit is used to instruct the tag nodes receiving the first information to select an uplink rate for sending the uplink reflection signal.

20. A method of communication, comprising: Applied to any tag node in N groups of tag nodes in a modulated reflection communication system, the communication method comprises: The first tag node receives a downlink excitation signal from a first node, and the downlink excitation signal comprises first information and N downlink instructions; wherein the first information comprises M uplink rates supported by this query and the number of groups of tag nodes supported by each of the M uplink rates, and each of the downlink instructions carries a target group identifier, the downlink instruction is used to trigger a group of tag nodes corresponding to the target group identifier carried by the downlink instruction to send an uplink reflection signal, and M and N are integers greater than 1. When the group identifier of the first tag node is the same as the target group identifier carried in one of the N downlink instructions, the first tag node selects an uplink rate from the M uplink rates according to the group identifier of the first tag node, the first information, and the signal strength of the received downlink excitation signal. The first tag node transmits the uplink reflection signal to the second node by using the selected uplink rate.

21. The communication method according to claim 20, wherein, The first tag node transmits the uplink reflection signal to the second node by using the selected uplink rate, comprising: If the selected uplink rate is selected by the second tag node, the first tag node and the second tag node transmit the uplink reflection signal by using the selected uplink rate in a time division duplex (TDD) mode; or, The first tag node transmits the uplink reflection signal to the second tag node by using the selected uplink rate and the second tag node transmits the uplink reflection signal to the first tag node by using another uplink rate selected from the M uplink rates in a frequency division duplex (FDD) mode.

22. The communication method according to claim 20 or 21, wherein, The first tag node receives the downlink excitation signal from the first node, comprising: The first tag node receives the downlink excitation signal transmitted by the first node in a TDD frame; the N downlink instructions included in the TDD frame are transmitted in a TDD mode.

23. The communication method according to claim 20 or 21, wherein, The first tag node receives the downlink excitation signal from the first node, comprising: The first tag node receives the downlink excitation signal transmitted by the first node in a TDD and FDD multiplexing frame; each downlink instruction transmitted at the same downlink rate among the N downlink instructions included in the TDD and FDD multiplexing frame is transmitted in a TDD mode, and each downlink instruction transmitted at a different downlink rate is transmitted in an FDD mode.

24. The communication method according to claim 20 or 21, wherein, The downlink excitation signal further comprises a charging bit; The charging bit is used to instruct the tag node receiving the first information to select an uplink rate for transmitting the uplink reflection signal.

25. The communication method according to claim 20 or 21, wherein, If a first uplink rate supports a group of tag nodes and a second uplink rate supports n groups of tag nodes, the second uplink rate is greater than or equal to n times the first uplink rate; wherein the first uplink rate is any one of the M uplink rates, and the second uplink rate is any one of the M uplink rates except the first uplink rate.

26. A method of communication, comprising: Comprising: The second node receives the uplink reflection signal from N groups of tag nodes within a preset time length; wherein the uplink rate used by each group of tag nodes when transmitting the uplink reflection signal is determined according to first information and signal strength of the received downlink excitation signal; the first information comprises M uplink rates supported by this query and group number of at least one group of tag nodes corresponding to each uplink rate in the M uplink rates; The second node demodulates the uplink reflection signal to obtain response information fed back by each group of tag nodes; The second node determines tag nodes that can be accessed in this query according to the response information fed back by each group of tag nodes; The second node transmits a confirmation access message to the accessible tag nodes, and the confirmation access message carries an identifier of the accessible tag nodes.

27. The communication method of claim 26, wherein, The second node receives the uplink reflection signal from N groups of tag nodes within a preset time length, comprising: The second node receives the uplink reflection signals sent by each group of tag nodes in time division duplex (TDD) mode at a first uplink rate and receives the uplink reflection signals sent by each group of tag nodes in TDD mode at a second uplink rate within the preset time length, wherein the uplink reflection signals sent by each group of tag nodes at the first uplink rate and the uplink reflection signals sent by each group of tag nodes at the second uplink rate are sent in frequency division duplex (FDD) mode.

28. The communication method according to claim 26 or 27, wherein, The second node demodulates the uplink reflection signals to obtain the response information fed back by each group of tag nodes, including: For the ith uplink rate in the M uplink rates, the i is a positive integer, the following is performed: If the ith uplink rate corresponds to one group of tag nodes, frequency filtering processing is performed on the uplink reflection signals received within the preset time length to filter out other uplink reflection signals except the frequency corresponding to the ith uplink rate, and the uplink reflection signals after the frequency filtering processing are demodulated in frequency shift keying (FSK) mode to obtain the response message sent by the one group of tag nodes corresponding to the ith uplink rate; If the ith uplink rate corresponds to q groups of tag nodes, the q is an integer greater than 1, the preset time length is equally divided into q time periods, the uplink reflection signals received in each time period are subjected to frequency filtering processing to filter out other uplink reflection signals except the frequency corresponding to the ith uplink rate, and the uplink reflection signals after the frequency filtering processing are demodulated in FSK mode to obtain the response message sent by each group of tag nodes corresponding to the ith uplink rate.

29. A communications device, characterized by The communication device comprises a processor coupled with a memory: The processor is configured to execute the computer program or instructions stored in the memory, so that the communication device performs the method in any one of claims 15 to 28.

30. A readable storage medium characterized by, The program or instructions are executed to perform the method in any one of claims 15 to 28.

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