Spectrum sensing method and device for TDD (Time Division Duplex) network and communication system

Abstract

The invention relates to the technical field of wireless communication, and particularly discloses a spectrum sensing method and device for a TDD (Time Division Duplex) network and a communication system, and the method comprises the steps that a time synchronization relation is established with a service terminal guard module, and the service terminal guard module can determine path time delay from a service base station to a service terminal according to the time synchronization relation; air interface time sequence information of the current service base station is obtained, air interface spectrum sensing on the service base station side is started when the downlink-to-uplink protection interval time sequence of the current service base station arrives, and the sensing duration of the air interface spectrum sensing on the service base station side is not larger than the duration of the downlink-to-uplink protection interval of the current service base station. According to the spectrum sensing method for the TDD network, provided by the invention, whether the downlink-to-uplink protection interval time sequence of the service base station arrives or not is monitored, and air interface spectrum sensing on the service base station side is started when the downlink-to-uplink protection interval time sequence of the service base station arrives, so that sensing identification on an air interface spectrum of a cellular network is realized.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a spectrum sensing method for a TDD network, a spectrum sensing device for a TDD network at a service base station side, a spectrum sensing device for a TDD network at a service terminal side, and a communication system. Background Art

[0002] Commercial cellular network technology represented by 5G, with its many excellent features such as large bandwidth, low latency, and ultra-large-scale networking, has significantly changed people's lifestyles and promoted the rapid progress of society. Commercial cellular networks all operate at specific operating frequencies, which are not allowed to be used by other wireless devices to prevent interference with communications. When cellular networks are applied to special fields, due to the lack of anti-interference capabilities of cellular networks, when encountering interference, it may cause communication degradation or even business interruption. In order to improve the anti-interference capability, it is first necessary to be able to perform situational awareness and identification of the air interface spectrum of the cellular network. There is no solution in the existing technology for how to perform situational awareness of the air interface spectrum of the cellular network.

[0003] Therefore, how to realize the perception and identification of the air interface spectrum of the cellular network has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] The present invention provides a spectrum sensing method for a TDD network, a spectrum sensing device for a TDD network on a service base station side, a spectrum sensing device for a TDD network on a service terminal side, and a communication system, to solve the problem of lack of sensing and identifying the air interface spectrum of a cellular network in the related art.

[0005] As a first aspect of the present invention, a spectrum sensing method for a TDD network is provided, wherein the spectrum sensing method is applied to a service base station node, the service base station node includes a service base station and a service base station guard module communicatively connected to the service base station, the service base station can be communicatively connected to a service terminal in a service terminal node and form a service network, and the service base station guard module can be communicatively connected to a service terminal guard module in the service terminal node and form a guard network; the spectrum sensing method for a TDD network includes:

[0006] Establishing a time synchronization relationship with a service terminal guard module, wherein the service terminal guard module can determine a path delay from a service base station to a service terminal according to the time synchronization relationship;

[0007] Obtain the air interface timing information of the current serving base station, and start the air interface spectrum sensing on the serving base station side after the downlink-to-uplink protection interval timing of the current serving base station arrives. The single sensing duration of the air interface spectrum sensing on the serving base station side is not greater than the duration of the downlink-to-uplink protection interval of the current serving base station. The service terminal guard module can start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the service terminal arrives. The single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current serving base station.

[0008] Further, the spectrum sensing method for the TDD network further includes the following steps before receiving the time synchronization request of the service terminal guard module:

[0009] Obtain the air interface parameters of the serving base station, where the air interface parameters at least include subcarrier spacing, uplink-downlink ratio, and radio frame time domain offset;

[0010] Provide a time synchronization signal to the serving base station, and obtain the air interface timing information of the serving base station after maintaining time synchronization with the serving base station;

[0011] Determine the radio frame boundary information, the start time of the downlink-to-uplink protection interval timing of the serving base station, and the duration of the downlink-to-uplink protection interval according to the air interface timing information of the serving base station.

[0012] Further, the single sensing duration of the air interface spectrum sensing on the serving base station side is less than or equal to the duration of the downlink-to-uplink protection interval of the current serving base station.

[0013] Further, the spectrum sensing method for the TDD network further includes:

[0014] Judge whether the sensing duration of the current air interface spectrum sensing on the serving base station side is less than a first preset threshold;

[0015] If the sensing duration of the current air interface spectrum sensing on the serving base station side is less than the first preset threshold, stop the current air interface spectrum sensing on the serving base station side.

[0016] As another aspect of the present invention, there is provided a spectrum sensing method for a TDD network, where it is applied to a service terminal node. The service terminal node includes a service terminal and a service terminal guard module communicatively connected to the service terminal. The service terminal can be communicatively connected to a serving base station in a serving base station node to form a service network. The service terminal guard module can be communicatively connected to a serving base station guard module in a serving base station node to form a guard network. The spectrum sensing method for the TDD network includes:

[0017] Establish a time synchronization relationship with the service base station guard module, and determine the path delay from the service base station to the service terminal according to the time synchronization relationship;

[0018] Obtain the air interface timing message of the current service base station, and start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the current service terminal arrives. The single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current service base station and is at least greater than the second preset threshold.

[0019] Further, the determining the path delay from the service base station to the service terminal according to the time synchronization relationship includes:

[0020] Send a time synchronization request to the service base station guard module at every preset time interval, and receive the synchronization response returned by the service base station guard module for each time synchronization request;

[0021] Determine the path delay and time adjustment amount from the service base station to the service terminal according to the sending time and receiving time of the time synchronization request and the sending time and receiving time of the synchronization response;

[0022] Among them, determining the path delay and time adjustment amount from the service base station to the service terminal according to the sending time and receiving time of the time synchronization request and the sending time and receiving time of the synchronization response includes:

[0023] Determine the first timestamp when the time synchronization request is sent according to the sending message of the time synchronization request, and determine the second timestamp when the synchronization response is received according to the receiving message of the synchronization response;

[0024] Determine the third timestamp when the synchronization response is sent according to the sending message of the service base station guard module for sending the synchronization response, and determine the fourth timestamp when the time synchronization request is received according to the receiving message of the service base station guard module for receiving the time synchronization request;

[0025] Calculate the path delay and time adjustment amount respectively according to the first timestamp, the second timestamp, the third timestamp and the fourth timestamp. Among them, the calculation formulas for the path delay Pt and the time adjustment amount Dt are respectively:

[0026] Pt = ((T4 - T1) - (T3 - T2)) / 2;

[0027] Dt = ((T2 - T1) - (T4 - T3)) / 2.

[0028] Further, the single sensing duration of the radio interface spectrum sensing on the service terminal side ≤ (the duration of the downlink-to-uplink protection interval of the current service base station - Pt - Pa), where Pt represents the path delay from the service base station node to the service terminal node, Pa represents the time advance of the service terminal node in the radio interface uplink timing, Pa = Pt + δ, and δ represents the processing capacity factor of the service terminal node.

[0029] As another aspect of the present invention, there is provided a spectrum sensing device for a TDD network on the service base station side, which is applied to a service base station node. The service base station node includes a service base station and a service base station guard module communicatively connected to the service base station. The service base station can be communicatively connected to a service terminal in the service terminal node to form a service network, and the service base station guard module can be communicatively connected to a service terminal guard module in the service terminal node to form a guard network. The spectrum sensing device for a TDD network on the service base station side includes:

[0030] A first time synchronization module, configured to establish a time synchronization relationship with the service terminal guard module, and the service terminal guard module can determine the path delay from the service base station to the service terminal according to the time synchronization relationship.

[0031] A first spectrum sensing module, configured to obtain the radio interface timing information of the current service base station, and start the radio interface spectrum sensing on the service base station side after the downlink-to-uplink protection interval timing of the current service base station arrives. The single sensing duration of the radio interface spectrum sensing on the service base station side is not greater than the duration of the downlink-to-uplink protection interval of the current service base station. The service terminal guard module can start the radio interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the service terminal arrives, and the single sensing duration of the radio interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current service base station.

[0032] As another aspect of the present invention, there is provided a spectrum sensing device for a TDD network on the service terminal side, which is applied to a service terminal node. The service terminal node includes a service terminal and a service terminal guard module communicatively connected to the service terminal. The service terminal can be communicatively connected to a service base station in the service base station node to form a service network, and the service terminal guard module can be communicatively connected to a service base station guard module in the service base station node to form a guard network. The spectrum sensing device for a TDD network on the service terminal side includes:

[0033] A second time synchronization module, configured to establish a time synchronization relationship with the service base station guard module, and determine the path delay from the service base station to the service terminal according to the time synchronization relationship.

[0034] A second spectrum sensing module, configured to obtain the air interface timing message of the current service base station, and start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or the uplink-to-downlink timing of the current service terminal arrives, where the single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current service base station and is at least greater than a second preset threshold.

[0035] As another aspect of the present invention, there is provided a communication system, which includes:

[0036] A service base station node and a service terminal node communicatively connected to the service base station node;

[0037] The service base station node includes a service base station and a service base station guard module communicatively connected to the service base station. The service base station guard module includes the spectrum sensing device on the service base station side for the TDD network described above;

[0038] The service terminal node includes a service terminal and a service terminal guard module communicatively connected to the service terminal. The service terminal guard module includes the spectrum sensing device on the service terminal side for the TDD network described above;

[0039] The service base station is communicatively connected to the service terminal to form a service network, and the service base station guard module and the service terminal guard module are communicatively connected to form a guard network.

[0040] In the spectrum sensing method for the TDD network provided by the present invention, after the service base station guard module establishes time synchronization with the service terminal guard module, it monitors whether the downlink-to-uplink protection interval timing of the service base station arrives, and starts the air interface spectrum sensing on the service base station side after the downlink-to-uplink protection interval timing of the service base station reaches, so as to be able to sense and identify the air interface spectrum of the cellular network through spectrum sensing, so as to assist in frequency switching to avoid interference when it is sensed that the frequency point is interfered. In the spectrum sensing method for the TDD network of the present invention, since the spectrum sensing is performed after the downlink-to-uplink protection interval timing of the service base station arrives, it will not be interfered by normal services and has the advantage of high accuracy of the sensing result; in addition, since the air interface spectrum sensing is performed during the downlink-to-uplink protection interval timing of the service base station, it will not affect normal communication and will not cause sensing errors due to normal communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the following specific embodiments to explain the present invention, but do not constitute a limitation to the present invention.

[0042] Figure 1Block diagram of the communication system provided by the present invention.

[0043] Figure 2 Block diagram of the service base station node provided by the present invention.

[0044] Figure 3 Block diagram of the service terminal node provided by the present invention.

[0045] Figure 4 Block diagram of the spectrum sensing device for TDD network on the service base station side provided by the present invention.

[0046] Figure 5 Flowchart of an implementation manner of the spectrum sensing method for TDD network provided by the present invention.

[0047] Figure 6 Timing diagram of the TDD service network provided by the present invention.

[0048] Figure 7 Schematic diagram of flexible time slot configuration of the 5G service network provided by the present invention.

[0049] Figure 8 Timing diagram of the service base station side and the service terminal side provided by the present invention.

[0050] Figure 9 Block diagram of the spectrum sensing device for TDD network on the service terminal side provided by the present invention.

[0051] Figure 10 Flowchart of another implementation manner of the spectrum sensing method for TDD network provided by the present invention.

[0052] Figure 11 Schematic diagram of the service terminal guard module calculating the path delay and the time adjustment amount.

[0053] Figure 12 Communication diagram of the service base station node and the service terminal node in the communication system provided by the present invention.

[0054] Figure 13 Architecture diagram of the TDD-5G service network provided by the present invention.

[0055] Figure 14 Timing configuration diagram of the TDD-5G service network provided by the present invention.

[0056] Figure 15 Schematic diagram of the specific implementation process of the spectrum sensing method for TDD network provided by the present invention. Detailed implementation manners

[0057] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0058] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0059] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to implement the embodiments of the present invention described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0060] Currently, when the cellular network is applied to commercial and other fields, due to its lack of anti-interference ability, when encountering interference, it may cause communication degradation or even service interruption.

[0061] Based on this, in the embodiments of the present invention, a communication system 10 is provided, as Figure 1 shown, which includes a service base station node 100 and a service terminal node 200 communicatively connected to the service base station node 100. The service base station node 100 includes a service base station 110 and a service base station guard module 120 communicatively connected to the service base station 110. The service terminal node 200 includes a service terminal 210 and a service terminal guard module 220 communicatively connected to the service terminal 210. The communication connection between the service base station 110 and the service terminal 210 can form a service network, and the communication connection between the service base station guard module 120 and the service terminal guard module 220 can form a guard network.

[0062] In the embodiments of the present invention, the service base station is mainly the base station of the service network, such as a 5G base station; the service base station guard module is mainly used to integrate with the service base station, support interconnection and interoperability with the service terminal guard module and other service base station guard modules, and form a guard network.

[0063] The service terminal is mainly the terminal of the service network, such as a 5G terminal; the service terminal guard module is mainly integrated with the service terminal, supporting interconnection and interoperability with the service base station guard module and other service terminal guard modules to form a guard network.

[0064] In addition, the service network is mainly a wireless communication network composed of service base stations and service terminals for service bearing, such as 4G cellular networks, 5G cellular networks, etc.; the guard network is mainly composed of service base station guard modules and service terminal guard modules, mainly used to provide the guard ability of cooperative frequency switching for service base stations or service terminals to avoid interference.

[0065] It should be understood that in the embodiment of the present invention, the service terminal deploys a service terminal guard module to build a guard network with the service base station guard module deployed on the service base station. The service terminal guard module receives a network cooperative frequency switching instruction from the service base station guard module, and this instruction notifies the occurrence time and target frequency point of the frequency change of the service terminal node. The service terminal guard module assists the service terminal in switching the radio interface frequency of the service terminal node to the target frequency point after the occurrence time of the frequency change arrives, ensuring that the service terminal and the service base station change frequencies synchronously, bypassing the standard 3GPP protocol processing process (that is, the frequency switching process keeps the working parameters and protocol process of the communication system unchanged). Through this method, the cellular network can sense the radio interface spectrum situation in real time and avoid interference.

[0066] It should be noted that when the service terminal does not deploy a terminal guard module, the frequency of the service terminal needs to be determined for the initial frequency and frequency switching through the standard 3GPP protocol. However, due to the problem of poor anti-interference ability of the 3GPP protocol itself, therefore, in the communication system provided by the present invention, by deploying a service terminal guard module on the service terminal and a service base station guard module on the service base station, the service terminal guard module and the service base station guard module can assist the service base station and the service terminal in synchronously changing the working frequency to achieve network cooperative frequency change. At the same time, the service terminal guard module deployed on the service terminal side interacts with different service base station guard modules and assists the service terminal in selecting the best cell for handover based on the communication measurement results, so as to ensure that the entire communication network has a strong anti-interference ability and realize the fast handover of the terminal device when moving at the cell edge, avoiding service interruption when the terminal device performs cell handover.

[0067] In the embodiment of the present invention, as Figure 2As shown, the service base station 110 and the service base station guard module 120 are communicatively connected through a radio frequency interface. The service base station guard module 120 can convert the operating frequency of the service base station 110 and transmit it on the service air interface of the service base station guard module 120, and can also convert the air interface frequency received on the service air interface and send it to the service base station 110 through the radio frequency interface. The service base station guard module 120 can send a timing signal to the service base station 110, and the time of the service base station guard module 120 is synchronized with the guard network.

[0068] Specifically, the service base station node consists of a service base station and a service base station guard module. The service base station 110 is interconnected with the service radio frequency interface of the service base station guard module 120 through a radio frequency interface. The transmitted signal (operating frequency) of the service base station is converted by the auxiliary frequency switching unit of the service base station guard module 120 and then transmitted on the service air interface of the service base station guard module 120 (air interface frequency). The signal (air interface frequency) received on the service air interface of the service base station guard module is converted by the auxiliary frequency switching unit of the service base station guard module 120 (operating frequency) and then sent to the radio frequency interface of the service base station through the service radio frequency interface. The whole process is transparent to the service base station. The operating frequency of the service base station is determined by the device capabilities and configurations, and the air interface frequency of the service base station node is controlled and determined by the service base station guard module.

[0069] In the embodiment of the present invention, the time synchronization signal of the service base station comes from the service base station guard module. The guard networks formed by the communication units between different guard modules can achieve guard network-level time synchronization. The service base station guard module can also achieve time synchronization by receiving an external clock signal (such as an external Beidou, 1588, etc. external synchronization source) through an external synchronization interface.

[0070] As Figure 3 shown, the service terminal 210 and the service terminal guard module 220 are communicatively connected through a radio frequency interface. The service terminal guard module 220 can convert the operating frequency of the service terminal 210 and transmit it on the service air interface of the service terminal guard module 220, and can also convert the air interface frequency received on the service air interface and send it to the service terminal 210 through the radio frequency interface. The time of the service terminal 210 is synchronized with the service base station 110, and the time of the service terminal guard module 220 is synchronized with the local guard network.

[0071] Specifically, the service terminal node consists of a service terminal and a service terminal guard module. The service terminal is interconnected with the service radio frequency interface of the service terminal guard module through a radio frequency interface. The transmitted signal (operating frequency) of the service terminal is frequency-converted by the auxiliary frequency switching unit and then sent out at the service air interface of the service terminal guard module (air interface frequency); the signal received at the service air interface of the service terminal guard module (air interface frequency) is frequency-converted by the auxiliary frequency switching unit (operating frequency) and then sent to the radio frequency interface of the service terminal via the service radio frequency interface. The whole process is transparent to the service terminal. The operating frequency of the service terminal is determined by the service terminal protocol stack, and the air interface frequency of the service terminal node is determined by the service terminal guard module according to the instructions of the service base station guard module, and is consistent with the affiliated service base station node.

[0072] In the embodiment of the present invention, the service terminal is synchronized with the service base station, and there is no need for the service terminal guard module to provide timing to the service terminal; the service terminal guard module and its affiliated service base station guard module maintain time synchronization through the guard network formed by the communication unit.

[0073] Therefore, in the embodiment of the present invention, taking the service base station guard module as the time reference, the service base station maintains time synchronization with the service base station guard module through the timing interface; the service terminal maintains air interface synchronization with the service base station through the standard air interface protocol; the service terminal guard module maintains time synchronization with the service base station guard module through the guard network; therefore, the entire communication system can form a unified timing reference.

[0074] As Figure 3 shown, taking the structural block diagram of the service terminal guard module 220 as an example, it at least includes an intelligent control unit 221, a communication unit 222, an auxiliary frequency switching unit 223, a spectrum sensing unit 224, and a clock unit 225.

[0075] Among them, the communication unit 222 interacts with other guard modules to build a guard network, establishes an interaction channel between the guard modules, and maintains the network-level time synchronization relationship between the guard modules; the communication unit provides a bearer service externally through the service interface, assists in expanding the coverage of the service network, and at the same time, when the service network is interrupted, it can also provide a guaranteed communication service.

[0076] The auxiliary frequency switching unit 223 is used to assist the external device (service base station / service terminal) connected to the service radio frequency interface to perform two-way switching between the operating frequency and the air interface frequency at a given moment under the control of the intelligent control unit, and the switching process is transparent to the external device.

[0077] The spectrum sensing unit 224 is used to sense and monitor the air interface spectrum situation under the control of the intelligent control unit;

[0078] The clock unit 225 can support providing synchronous time service for external devices through the time service interface; meanwhile, the clock unit also provides clock service for other units of the guard module. When an external synchronization signal is input, the clock unit can adjust the local clock based on the external synchronization signal; when no external synchronization signal is input, the clock unit can adjust the local clock according to the output of the communication unit.

[0079] The intelligent control unit 221 obtains the air interface spectrum situation of its own module through the spectrum sensing unit, shares and exchanges the spectrum situations of each other with other modules through the communication unit, forms a collaborative frequency usage strategy, and generates specific air interface frequency change moments and specific frequency point numbers to be used based on this frequency usage strategy, and spreads them to the intelligent control units of other modules through the communication unit, and collaboratively controls the auxiliary frequency switching unit to synchronously switch frequencies, so as to realize the real-time change of the air interface frequency of the service network and avoid interference; the intelligent control unit can also perform collaborative control on the analog base station and the terminal through the control interface.

[0080] The service air interface is specifically represented as the input / output interface of the service network air interface frequency, that is, the actual air interface of the service network; the guard air interface is specifically represented as the air interface of the guard network, which is multiplexed by the communication unit and the spectrum sensing unit.

[0081] When the above communication system realizes interference avoidance, it is necessary to perform spectrum sensing on the service network air interface frequency to realize interference avoidance when it is determined that there is interference. Therefore, in order to sense the interference of the service air interface frequency, the spectrum sensing unit of the service base station guard module at least includes a spectrum sensing device for the TDD network on the service base station side, and the spectrum sensing unit of the service terminal guard module at least includes a spectrum sensing device for the TDD network on the service terminal side.

[0082] Setting a spectrum sensing device for the TDD network on the service base station side in the service base station guard module can start the air interface spectrum sensing on the service base station side after the downlink-to-uplink protection interval timing of the service base station arrives according to the air interface timing message of the service base station, so as to perform frequency switching to avoid interference when it is sensed that the frequency point is interfered, thereby effectively improving the anti-interference ability of the communication system.

[0083] Correspondingly, a spectrum sensing device for the TDD network is set on the service terminal side in the service terminal guard module. It can, according to the air interface timing message of the service base station, start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the current service terminal arrives. And since the service terminal guard module and the service base station guard module belong to the same guard network, they can maintain time synchronization. Furthermore, the sensing of the frequency points to be sensed can also be synchronized. That is, when an abnormal frequency point is sensed, frequency switching can be achieved in a collaborative manner to avoid interference, and together with the service base station guard module, the anti-interference ability of the communication system can be improved.

[0084] As another embodiment of the present invention, a spectrum sensing device for the TDD network on the service base station side is provided, which is used to implement the spectrum sensing method for the TDD network described below, as Figure 4 shown, the spectrum sensing device 300 for the TDD network on the service base station side includes:

[0085] A first time synchronization module 310, which is used to establish a time synchronization relationship with the service terminal guard module, and the service terminal guard module can determine the path delay from the service base station to the service terminal according to the time synchronization relationship;

[0086] A first spectrum sensing module 320, which is used to obtain the air interface timing information of the current service base station and start the air interface spectrum sensing on the service base station side after the downlink-to-uplink protection interval timing of the current service base station arrives. The single sensing duration of the air interface spectrum sensing on the service base station side is not greater than the duration of the downlink-to-uplink protection interval of the current service base station. The service terminal guard module can start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the service terminal arrives, and the single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current service base station.

[0087] In the embodiment of the present invention, after the service base station guard module establishes time synchronization with the service terminal guard module, it monitors whether the downlink-to-uplink protection interval timing of the service base station arrives, and starts the air interface spectrum sensing on the service base station side when the downlink-to-uplink protection interval timing of the service base station arrives. Thus, the air interface spectrum of the cellular network can be sensed and identified through spectrum sensing, so as to be able to perform frequency switching to avoid interference when the frequency point is sensed to be interfered. Since the spectrum sensing is performed after the downlink-to-uplink protection interval timing of the service base station arrives, it will not be interfered by normal services, and has the advantage of high accuracy of sensing results; in addition, since the air interface spectrum sensing is performed during the downlink-to-uplink protection interval timing of the service base station, it will not affect normal communication, and will not cause sensing errors due to normal communication.

[0088] As another embodiment of the present invention, a spectrum sensing method for a TDD network is provided, which is applied to a service base station node. Figure 5 It is a flowchart of the spectrum sensing method for a TDD network provided according to an embodiment of the present invention, as Figure 5 shown, the spectrum sensing method for a TDD network includes:

[0089] S110. Establish a time synchronization relationship with a service terminal guard module, and the service terminal guard module can determine the path delay from the service base station to the service terminal according to the time synchronization relationship;

[0090] In the embodiment of the present invention, the service base station guard module maintains time synchronization with the service terminal guard module through a guard network.

[0091] When specifically maintaining time synchronization, the service terminal guard module can periodically initiate a time synchronization request to the service base station guard module, and the service base station guard module will feedback a synchronization response after receiving the time synchronization request. Therefore, the service base station guard module and the service terminal guard module achieve time synchronization.

[0092] S120. Obtain the air interface timing information of the current service base station, and start the air interface spectrum sensing on the service base station side after the downlink-to-uplink protection interval timing of the current service base station arrives. The single sensing duration of the air interface spectrum sensing on the service base station side is not greater than the duration of the downlink-to-uplink protection interval of the current service base station. The service terminal guard module can start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the service terminal arrives, and the single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current service base station.

[0093] It should be noted that on the service base station side, since the air interface spectrum sensing can be performed multiple times repeatedly, therefore, when performing each sensing, the single sensing duration of the air interface spectrum sensing is compared with the duration of the downlink-to-uplink protection interval of the service base station.

[0094] On the basis of the service base station guard module achieving time synchronization with the service terminal guard module through the guard network, it continuously senses the air interface timing information of its own service base station, and starts the air interface spectrum sensing on the service base station side after the downlink-to-uplink protection interval timing of the current service base station arrives. That is, the service base station guard module in the embodiment of the present invention can perform air interface spectrum sensing during the downlink-to-uplink protection interval timing of the service base station.

[0095] Therefore, in the spectrum sensing method for a TDD network provided by the embodiments of the present invention, after the service base station guard module establishes time synchronization with the service terminal guard module, it monitors whether the downlink-to-uplink protection interval timing of the service base station arrives, and starts the air interface spectrum sensing on the service base station side after the downlink-to-uplink protection interval timing of the service base station reaches. Thus, it can sense and identify the air interface spectrum of the cellular network through spectrum sensing, so as to assist in frequency switching to avoid interference when it is sensed that the frequency point is interfered. In the spectrum sensing method for a TDD network of the present invention, since the spectrum sensing is performed after the downlink-to-uplink protection interval timing of the service base station arrives, it will not be interfered by normal services and has the advantage of high accuracy of the sensing result; in addition, since the air interface spectrum sensing is performed during the downlink-to-uplink protection interval timing of the service base station, it will not affect normal communication and will not cause sensing errors due to normal communication.

[0096] In the embodiments of the present invention, specifically, it can receive the time synchronization request of the service terminal guard module and send a synchronization response to the service terminal guard module to maintain time synchronization with the service terminal guard module. Of course, other well-known time synchronization methods by those skilled in the art can also be adopted, which will not be elaborated here.

[0097] The service terminal guard module can determine the path delay from the service base station to the service terminal according to the sending time and receiving time of the time synchronization and the sending time and receiving time of the synchronization response.

[0098] As Figure 6 shown, in a TDD service network, the radio frame sent by the service base station will take the time of the path delay to reach the service terminal; when the service terminal performs an uplink transmission, it needs to send in advance by the air interface time advance amount of the service base station to ensure that the signals of service terminals at different positions reach the service base station at approximately the same time.

[0099] As Figure 7 shown, 5G supports flexible uplink and downlink ratio configurations. Therefore, flexible time slots are set, and each flexible time slot consists of several downlink symbols, flexible symbols (Flexible Symbols), and uplink symbols, where the flexible symbols can be used for protection during uplink and downlink conversion. As Figure 7 shown is a kind of uplink and downlink configuration of a TDD-5G cell.

[0100] In the embodiments of the present invention, the spectrum sensing method for a TDD network further includes the following steps before receiving the time synchronization request of the service terminal guard module:

[0101] Obtain the air interface parameters of the service base station, where the air interface parameters at least include subcarrier spacing, uplink and downlink ratio, and radio frame time domain offset;

[0102] Provide a time synchronization signal to the serving base station, and obtain the air interface timing information of the serving base station after maintaining time synchronization with the serving base station;

[0103] Determine the radio frame boundary information, the start time of the downlink to uplink protection interval timing of the serving base station, and the duration of the downlink to uplink protection interval according to the air interface timing information of the serving base station.

[0104] It should be noted that the serving base station guard module can obtain the air interface parameters (subcarrier spacing, uplink and downlink ratio, radio frame time domain offset, etc.) of each cell on the serving base station through configuration or interaction with the serving base station. After the serving base station guard module is started, it provides a time synchronization signal to the serving base station through the timing interface; therefore, through the cell air interface parameters, the serving base station guard module can accurately obtain the radio frame boundary related information such as the frame, subframe, time slot, symbol, etc. of the serving base station, as well as the start time and length of the protection interval. The serving base station guard module spreads the cell air interface parameters and spectrum sensing parameters of the serving base station to the service terminal guard module through the guard network.

[0105] In the embodiment of the present invention, the single sensing duration of the air interface spectrum sensing on the serving base station side is less than or equal to the duration of the downlink to uplink protection interval of the current serving base station. It should be understood that the serving base station guard module starts the air interface spectrum sensing when it determines that the downlink to uplink protection interval timing of the serving base station arrives, and the maximum sensing duration ≤ the protection interval length.

[0106] Specifically, the spectrum sensing method for the TDD network further includes:

[0107] Judge whether the sensing duration of the current air interface spectrum sensing on the serving base station side is less than a first preset threshold;

[0108] If the sensing duration of the current air interface spectrum sensing on the serving base station side is less than the first preset threshold, stop the current air interface spectrum sensing on the serving base station side.

[0109] It should be understood that in order to ensure that the air interface spectrum sensing on the serving base station side can be realized during the downlink to uplink protection interval timing, the single sensing duration for the air interface spectrum sensing needs to be at least greater than or equal to the first preset threshold, and this first preset threshold can ensure that the serving base station side completes the sensing of its own air interface spectrum. Within the maximum sensing duration, if the sensing of its own air interface spectrum is completed, the air interface spectra of other service networks can also be sensed.

[0110] It should be noted that for the downlink to uplink protection interval of the serving base station, since there is a time advance in the cellular network, there is usually no such protection interval definition, so the spectrum sensing on the serving base station side is also carried out during the downlink to uplink protection interval timing.

[0111] As shown Figure 8 in the figure, it is the air interface timing relationship on the service base station side and the service terminal side.

[0112] In the embodiments of the present invention, there is no constraint on the sensing frequency when using the guard interval for air interface spectrum sensing; when using the non-guard interval for air interface spectrum sensing, it is required that the sensing frequency is not equal to the air interface frequency of the service network.

[0113] In summary, for the spectrum sensing method for TDD networks provided by the present invention, the service base station guard module can conveniently collect the spectrum situation information of the entire network, providing a basis for subsequent interference identification and avoidance, and network collaborative optimization. Especially for TDD networks, this method utilizes the guard interval during the uplink-downlink handover unique to TDD networks to achieve spectrum sensing of the actual working frequency of the current service network without affecting the transmission of the service network, avoiding interference from the service network to spectrum sensing, and the entire detection process is imperceptible to the service network.

[0114] As another embodiment of the present invention, there is provided a spectrum sensing device for a TDD network on the service terminal side, which is used to implement the spectrum sensing method for a TDD network described below. As shown Figure 9 in the figure, the spectrum sensing device 400 for a TDD network on the service terminal side includes:

[0115] A second time synchronization module 410, which is used to establish a time synchronization relationship with the service base station guard module and determine the path delay from the service base station to the service terminal according to the time synchronization relationship;

[0116] A second spectrum sensing module 420, which is used to obtain the air interface timing message of the current service base station, and start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the current service terminal arrives, where the single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink guard interval of the current service base station and is at least greater than a second preset threshold.

[0117] In the embodiments of the present invention, a spectrum sensing device for a TDD network on the service terminal side is set in the service terminal guard module. It can start the air interface spectrum sensing on the service terminal side according to the air interface timing message of the service base station after the downlink-to-uplink timing or uplink-to-downlink timing of the current service terminal arrives. And since the service terminal guard module and the service base station guard module belong to the same guard network, they can maintain time synchronization. Furthermore, the sensing of the frequency points to be sensed can also be synchronized. That is, when an abnormal frequency point is sensed, frequency switching can be achieved in a coordinated manner to avoid interference, and jointly with the service base station guard module, the anti-interference ability of the communication system can be improved.

[0118] As another embodiment of the present invention, a spectrum sensing method for a TDD network is provided, which is applied to a service terminal node. Figure 10 It is a flowchart of the spectrum sensing method for a TDD network provided by an embodiment of the present invention. As Figure 10 shown, the spectrum sensing method for a TDD network includes:

[0119] S210. Establish a time synchronization relationship with the service base station guard module, and determine the path delay from the service base station to the service terminal according to the time synchronization relationship;

[0120] In the embodiment of the present invention, the service terminal guard module periodically sends a time synchronization request to the service base station guard module, and can receive the synchronization reply returned by the service base station guard module for each time synchronization request, so as to achieve time synchronization with the service base station guard module.

[0121] S220. Obtain the air interface timing message of the current service base station, and start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the current service terminal arrives, where the single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current service base station and is at least greater than the second preset threshold.

[0122] It should be understood that on the service terminal side, since the air interface spectrum sensing can also be performed multiple times repeatedly, therefore, during each sensing, the single sensing duration of the air interface spectrum sensing is compared with the duration of the downlink-to-uplink protection interval of the service base station.

[0123] In the embodiment of the present invention, after maintaining time synchronization with the service base station guard module, the air interface timing of the current service terminal is also monitored based on the air interface timing message of the service base station. After the downlink-to-uplink timing or uplink-to-downlink timing of the current service terminal arrives, the air interface sensing on the service terminal side is started. And since the service terminal guard module and the service base station guard module belong to the same guard network, they can maintain time synchronization. Furthermore, the sensing of the frequency points to be sensed can also be synchronized, realizing the sensing and identification of the air interface spectrum of the cellular network, so as to assist in realizing frequency switching when an abnormal frequency point is sensed to avoid interference, and jointly acting with the service base station guard module to achieve the effect of improving the anti-interference ability of the communication system.

[0124] Specifically, the determining the path delay from the service base station to the service terminal according to the time synchronization relationship includes:

[0125] Send a time synchronization request to the service base station guard module at every preset time interval, and receive the synchronization reply returned by the service base station guard module for each time synchronization request;

[0126] Determine the path delay and time adjustment amount from the service base station to the service terminal according to the sending time and receiving time of the time synchronization request and the sending time and receiving time of the synchronization response;

[0127] The path delay and time adjustment amount from the service base station to the service terminal are determined according to the sending time and receiving time of the time synchronization request and the sending time and receiving time of the synchronization response, including:

[0128] Determine a first timestamp when the time synchronization request is sent according to a sending message of the time synchronization request, and determine a second timestamp when the synchronization response is received according to a receiving message of the synchronization response;

[0129] Determine a third timestamp when the synchronization response is sent according to a sending message of the synchronization response sent by the service base station guard module, and determine a fourth timestamp when the time synchronization request is received according to a receiving message of the time synchronization request received by the service base station guard module;

[0130] The path delay and the time adjustment amount are calculated respectively according to the first timestamp, the second timestamp, the third timestamp and the fourth timestamp, wherein the calculation formulas of the path delay Pt and the time adjustment amount Dt are respectively:

[0131] Pt = ((T4-T1)-(T3-T2)) / 2;

[0132] Dt=((T2-T1)-(T4-T3)) / 2.

[0133] It should be understood that when the service terminal guard module and the service base station guard module maintain time synchronization, the service terminal guard module periodically initiates a synchronization request to the service base station guard module (the request message carries the timestamp T1 of the message sending time); after receiving the request, the service base station guard module sends a synchronization response to the service terminal guard module (the response message carries the timestamp T1 of the original sending time of the request message, the timestamp T2 of the local receiving time of the request message, and the timestamp T3 of the sending time of the response message); after receiving the message, the service terminal guard module records the timestamp T4 of the local receiving time; based on T1~T4, the service terminal guard module can calculate the path delay Pt and the time adjustment amount Dt from the service base station to the service terminal, such as Figure 11 shown.

[0134] In an embodiment of the present invention, the single perception duration of the air interface spectrum perception on the service terminal side is ≤(the duration of the downlink to uplink protection interval of the current service base station - Pt - Pa), Pt represents the path delay from the service base station node to the service terminal node, Pa represents the time advance of the service terminal node in the air interface uplink timing, Pa = Pt + δ, δ represents the processing capability factor of the service terminal node.

[0135] It should be understood that the service terminal guard module needs to start the air interface spectrum sensing after a delay of Pt. Therefore, the maximum single sensing duration of the service terminal guard module ≤ (guard interval length - Pt - Pa), where the guard interval length is the duration of the downlink to uplink guard interval of the current service base station as described above. At the same time, to ensure sensing on the service terminal side, a second preset threshold is set, that is, the single sensing duration on the service terminal side needs to be greater than or equal to the second preset threshold. If the maximum single sensing duration is less than the second preset threshold, the service terminal guard module does not support using this guard interval for air interface spectrum sensing.

[0136] In an embodiment of the present invention, the service terminal guard module can also determine the reporting timing of the spectrum sensing result according to the spectrum sensing parameters.

[0137] The service base station guard module can schedule the sensing frequency, sensing time, and reporting timing of the specified service terminal guard module through the guard network. The service terminal guard module can upload the sensing result to the service base station guard module through the guard network for the service base station guard module to perform network-level real-time spectrum adjustment to avoid interference.

[0138] In summary, the spectrum sensing method for the TDD network on the service terminal side provided by the present invention, after keeping time synchronization with the service base station guard module, also monitors the air interface timing of the current service terminal based on the air interface timing message of the service base station. After the downlink to uplink timing or uplink to downlink timing of the current service terminal arrives, the air interface sensing on the service terminal side is started. And since the service terminal guard module and the service base station guard module belong to the same guard network, they can keep time synchronization. Furthermore, the sensing of the frequency points to be sensed can also be kept synchronized, realizing the sensing and identification of the air interface spectrum of the cellular network, so as to assist in realizing frequency switching when abnormal frequency points are sensed to avoid interference, and jointly acting with the service base station guard module to achieve the effect of improving the anti-interference ability of the communication system.

[0139] The following details the specific working process of the spectrum sensing method for the TDD network provided by the present invention.

[0140] As Figure 12 shown, the operating frequency of the service network is F1, that is, the operating frequency of the service base station deployed cell and the service terminal is F1. After frequency conversion by the guard module, the air interface frequency of the service network becomes F1'.

[0141] As Figure 13 and Figure 14 shown, the TDD-5G network (service network) has a configuration period of 5 ms, and the air interface up / downlink ratio is: 7 downlink time slots, 2 uplink time slots, and 1 flexible time slot, where the flexible time slot contains 6 downlink symbols, 4 uplink symbols, and 4 guard symbols.

[0142] The service base station guard module can initially obtain the air interface parameter configuration information of each cell on the service base station through configuration, including: subcarrier spacing (30 kHz), downlink time slots (7), uplink time slots (2), downlink symbols (6), uplink symbols (4), normal CP, wireless frame time domain offset (frame boundary aligned with the whole second boundary), etc. In the embodiment of the present invention, 2 more symbols are configured for spectrum sensing.

[0143] As Figure 15 shown, the service base station guard module provides timing (provides a time synchronization signal) to the service base station through the timing interface; the service base station periodically spreads its own parameter information to the service terminal guard module in the form of broadcasting. This message (service base station parameter broadcast) at least includes: message sequence number, service base station ID (1), working cell ID, cell working frequency (F1), cell air interface frequency (), transmit power, subcarrier spacing (30 kHz), downlink time slots (7), uplink time slots (2), downlink symbols (6), uplink symbols (4), normal CP, wireless frame time domain offset (frame boundary aligned with the whole second boundary), air interface common sensing time domain resource (guard interval: length 2 symbols), air interface frequency information to be sensed (F1’), default reporting period (1 second), etc.

[0144] After the service terminal guard module accesses the guard network, it keeps time synchronization with the service base station guard module (obtains the air interface path delay and time adjustment amount through the synchronization request and synchronization response mechanism, and adjusts its own clock to keep time synchronization with the service base station guard module).

[0145] The service base station and the service terminal realize air interface service bearer through the service network; after the service terminal guard module works normally, it will perform its own spectrum sensing scheduling based on the received service base station parameter broadcast (prioritize sensing the frequencies indicated by the air interface frequency information to be sensed in the guard interval, and other frequencies can be sensed at any idle moment).

[0146] In the embodiment of the present invention, the service terminal guard module reports the sensing results at the default reporting period.

[0147] The service base station guard module can also indicate a specific service terminal guard module to perform spectrum sensing in a specific manner through a dedicated "sensing scheduling indication" message. This message at least includes: message sequence number, service base station ID (1), working cell ID, cell working frequency (F1), cell air interface frequency (F1’), air interface dedicated sensing time domain resource (guard interval), air interface dedicated frequency information to be sensed (F2’, F3’), reporting period (100 milliseconds), etc.

[0148] The service terminal guard module performs its own spectrum sensing scheduling based on the received dedicated "sensing scheduling indication" message (sensing the frequency information dedicated to the air interface to be sensed preferentially in the guard interval, and other frequencies can be sensed at any idle moment); the service terminal guard module reports the sensing results at the reporting period indicated by the "sensing scheduling indication" message.

[0149] In summary, for the spectrum sensing method for TDD networks provided by the present invention, the service base station guard module can conveniently collect the spectrum situation information of the entire network, providing a basis for subsequent interference identification and avoidance, and network collaborative optimization. Specifically for TDD networks, this method utilizes the guard interval during the uplink-downlink handover unique to TDD networks to achieve spectrum sensing of the actual operating frequencies of the current service network without affecting the service network transmission, avoiding interference from the service network to spectrum sensing, and the entire detection process is imperceptible to the service network.

[0150] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A spectrum sensing method for a TDD network, characterized in that, Applied to a service base station node, the service base station node includes a service base station and a service base station guard module communicatively connected to the service base station. The service base station can be communicatively connected to a service terminal in a service terminal node to form a service network, and the service base station guard module can be communicatively connected to a service terminal guard module in the service terminal node to form a guard network; The spectrum sensing method for a TDD network includes: Establishing a time synchronization relationship with the service terminal guard module, and the service terminal guard module can determine the path delay from the service base station to the service terminal according to the time synchronization relationship; Obtaining the air interface timing information of the current service base station, and starting the air interface spectrum sensing on the service base station side after the downlink-to-uplink protection interval timing of the current service base station arrives. The single sensing duration of the air interface spectrum sensing on the service base station side is not greater than the duration of the downlink-to-uplink protection interval of the current service base station. The service terminal guard module can start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the service terminal arrives. The single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current service base station.

2. The spectrum sensing method for a TDD network according to claim 1, wherein The spectrum sensing method for a TDD network further includes the steps before receiving the time synchronization request from the service terminal guard module: Obtaining the air interface parameters of the service base station, and the air interface parameters at least include subcarrier spacing, uplink-downlink ratio, and radio frame time domain offset; Providing a time synchronization signal to the service base station, and obtaining the air interface timing information of the service base station after maintaining time synchronization with the service base station; Determining the radio frame boundary information, the start time of the downlink-to-uplink protection interval timing of the service base station, and the duration of the downlink-to-uplink protection interval according to the air interface timing information of the service base station.

3. The spectrum sensing method for a TDD network according to claim 1, wherein The single sensing duration of the air interface spectrum sensing on the service base station side is less than or equal to the duration of the downlink-to-uplink protection interval of the current service base station.

4. The spectrum sensing method for a TDD network according to claim 1, characterized in that The spectrum sensing method for a TDD network further includes: Judging whether the sensing duration of the current air interface spectrum sensing on the service base station side is less than a first preset threshold; If the sensing duration of the current air interface spectrum sensing on the service base station side is less than the first preset threshold, stopping the current air interface spectrum sensing on the service base station side.

5. A spectrum sensing method for a TDD network, characterized in that, Applied to a service terminal node, the service terminal node includes a service terminal and a service terminal guard module communicatively connected to the service terminal. The service terminal can be communicatively connected to a service base station in a service base station node to form a service network, and the service terminal guard module can be communicatively connected to a service base station guard module in the service base station node to form a guard network; The spectrum sensing method for a TDD network includes: Establishing a time synchronization relationship with the service base station guard module, and determining the path delay from the service base station to the service terminal according to the time synchronization relationship; Obtain the air interface timing message of the current service base station, and start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the current service terminal arrives. The single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current service base station and is at least greater than the second preset threshold.

6. The spectrum sensing method for a TDD network according to claim 5, characterized in that, The determining the path delay from the service base station to the service terminal according to the time synchronization relationship includes: Send a time synchronization request to the service base station guard module at every preset time interval, and receive the synchronization response returned by the service base station guard module for each time synchronization request; Determine the path delay and time adjustment amount from the service base station to the service terminal according to the sending time and receiving time of the time synchronization request and the sending time and receiving time of the synchronization response; Among them, determining the path delay and time adjustment amount from the service base station to the service terminal according to the sending time and receiving time of the time synchronization request and the sending time and receiving time of the synchronization response includes: Determine the first timestamp when the time synchronization request is sent according to the sending message of the time synchronization request, and determine the second timestamp when the synchronization response is received according to the receiving message of the synchronization response; Determine the third timestamp when the synchronization response is sent according to the sending message of the synchronization response sent by the service base station guard module, and determine the fourth timestamp when the time synchronization request is received according to the receiving message of the service base station guard module receiving the time synchronization request; Calculate the path delay and time adjustment amount respectively according to the first timestamp, the second timestamp, the third timestamp and the fourth timestamp. Among them, the calculation formulas for the path delay Pt and the time adjustment amount Dt are respectively: Pt = ((T4 - T1) - (T3 - T2)) / 2; Dt = ((T2 - T1) - (T4 - T3)) / 2.

7. The spectrum sensing method for a TDD network according to claim 6, wherein The single sensing duration of the air interface spectrum sensing on the service terminal side ≤ (the duration of the downlink-to-uplink protection interval of the current service base station - Pt - Pa), where Pt represents the path delay from the service base station node to the service terminal node, Pa represents the time advance amount of the service terminal node in the air interface uplink timing, Pa = Pt + δ, and δ represents the processing capacity factor of the service terminal node.

8. A spectrum sensing device for a TDD network on the service base station side, characterized in that Applied to the service base station node, the service base station node includes a service base station and a service base station guard module communicatively connected to the service base station. The service base station can be communicatively connected to the service terminal in the service terminal node to form a service network, and the service base station guard module can be communicatively connected to the service terminal guard module in the service terminal node to form a guard network; The spectrum sensing device for the TDD network on the service base station side includes: The first time synchronization module is used to establish a time synchronization relationship with the service terminal guard module, and the service terminal guard module can determine the path delay from the service base station to the service terminal according to the time synchronization relationship; A first spectrum sensing module, configured to obtain the air interface timing information of the current serving base station, and start the air interface spectrum sensing on the serving base station side after the downlink-to-uplink protection interval timing of the current serving base station arrives, wherein the single sensing duration of the air interface spectrum sensing on the serving base station side is not greater than the duration of the downlink-to-uplink protection interval of the current serving base station. The service terminal guard module can start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the service terminal arrives, and the single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current serving base station.

9. A spectrum sensing device for a TDD network on the service terminal side, characterized in that Applied to a service terminal node, the service terminal node includes a service terminal and a service terminal guard module communicatively connected to the service terminal. The service terminal can be communicatively connected to a serving base station in a serving base station node to form a service network, and the service terminal guard module can be communicatively connected to a serving base station guard module in a serving base station node to form a guard network; The spectrum sensing device for a TDD network on the service terminal side includes: A second time synchronization module, configured to establish a time synchronization relationship with the serving base station guard module, and determine the path delay from the serving base station to the service terminal according to the time synchronization relationship; A second spectrum sensing module, configured to obtain the air interface timing message of the current serving base station, and start the air interface spectrum sensing on the service terminal side after the downlink-to-uplink timing or uplink-to-downlink timing of the current service terminal arrives, wherein the single sensing duration of the air interface spectrum sensing on the service terminal side is less than the duration of the downlink-to-uplink protection interval of the current serving base station and is at least greater than a second preset threshold.

10. A communication system, characterized in that, Including: A serving base station node and a service terminal node communicatively connected to the serving base station node; The serving base station node includes a serving base station and a serving base station guard module communicatively connected to the serving base station. The serving base station guard module includes the spectrum sensing device for a TDD network on the serving base station side as claimed in claim 8; The service terminal node includes a service terminal and a service terminal guard module communicatively connected to the service terminal. The service terminal guard module includes the spectrum sensing device for a TDD network on the service terminal side as claimed in claim 9; The serving base station is communicatively connected to the service terminal to form a service network, and the serving base station guard module and the service terminal guard module are communicatively connected to form a guard network.

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