Spectrum map based radio frequency link handover path pre-planning method

Abstract

The application discloses a spectrum map-based radio frequency link switching path pre-planning method, and particularly relates to the technical field of radio frequency link switching management in wireless communication networks, and is used for solving the problem that in the existing cross-base station switching path pre-planning, the pre-planned path is rejected at the target base station side due to the spectrum map state offset between the source base station and the target base station; the method is achieved by calculating the time deviation at the target base station side, and when the deviation exceeds the preset range, the historical state record is called to evaluate the conditional probability of the failure infection between adjacent links in the pre-planned switching sequence to determine the infection risk link, and then the concurrent resource competition intensity ratio of the infection risk link is calculated to evaluate the amplification effect of the infection risk caused by the concurrent competition, the link availability confidence of the infection risk link affected by the amplification effect is reduced and replaced by the link reselected based on the current local spectrum map, an updated pre-planned switching sequence is formed, and cross-base station resource reservation is performed.

Description

Technical Field

[0001] This invention relates to the field of radio frequency link switching management technology in wireless communication networks, and more specifically, to a method for pre-planning radio frequency link switching paths based on spectrum maps. Background Technology

[0002] In the networking and operation of next-generation mobile communication base station equipment, digital program-controlled exchanges, and other communication system equipment, base station equipment acquires and maintains spectrum maps reflecting the spatial distribution and temporal changes of the radio electromagnetic environment. This provides a reference for radio frequency link handover decisions for mobile terminals within its coverage area. The spectrum map integrates multi-dimensional data such as spectrum sensing, geographic information, and historical channel status, enabling base station equipment to assess the expected quality of candidate links in advance, even before the mobile terminal reaches the target coverage area. Based on the terminal's direction and speed of movement, it can pre-plan a handover path sequence containing multiple handover nodes. Compared to instantaneous handover triggered solely by real-time measurements, this effectively reduces handover latency and improves link continuity.

[0003] However, when the handover path crosses multiple base stations, the source base station needs to send the planned path sequence to the downstream target base station in advance to complete resource negotiation and reservation. Due to the inherent differences in the construction method, update cycle and internal processing timing of different base stations, the path plan generated by the source base station based on its own spectrum map snapshot has deviated from the electromagnetic environment prediction state it is based on when it reaches the target base station. This makes it impossible for the target base station to complete the effective reservation of handover resources according to the expected link state requested by the source base station, resulting in the pre-planned path being rejected in the cross-base station link, which affects the reliable execution of the handover path pre-planning method in multi-base station networks. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, the present invention provides a pre-planning method for radio frequency link switching paths based on spectrum maps to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A spectrum map-based method for pre-planning RF link switching paths includes: S1. The source base station generates a pre-planned handover sequence containing the expected arrival time based on the local spectrum map and the terminal's mobility status. S2. The source base station sends a pre-planning request carrying the expected arrival time to the first non-local target base station in the pre-planned handover sequence. S3. Extract the expected arrival time from the target base station and calculate the time deviation between the expected arrival time and the latest update time of the local spectrum map. S4. When the time deviation exceeds the preset range, the target base station retrieves the historical status records of the local spectrum map, calculates the conditional probability of failure infection of adjacent links in the pre-planned handover sequence within the time deviation, and identifies the subsequent links with conditional probabilities higher than the infection threshold as infection risk links. S5. The target base station obtains concurrent pre-planning requests submitted by other terminals, calculates the concurrent resource contention intensity ratio for the infection risk links, and reduces the link availability confidence of infection risk links whose concurrent resource contention intensity ratio exceeds the amplification threshold to below the confidence threshold. S6. The target base station replaces links whose link availability confidence is lower than the confidence threshold with links reselected based on the current local spectrum map, forming an updated pre-planned handover sequence and performing cross-base station resource reservation.

[0006] Furthermore, the source base station generates a pre-planned handover sequence containing the expected arrival time based on the local spectrum map and the terminal's mobility status, including: Extract the channel quality parameters and spectrum occupancy status records of each candidate link from the local spectrum map; The arrival time of the terminal to the coverage area of ​​each candidate link is estimated based on the direction and speed of movement in the terminal's movement state. Candidate links that meet the preset channel quality threshold and whose spectrum occupancy status is recorded as available are identified as switching nodes; The handover nodes are connected in series according to the direction of terminal movement, and the arrival time of each handover node is taken as the expected arrival time, forming a pre-planned handover sequence that includes multiple handover nodes and their corresponding expected arrival times.

[0007] Furthermore, the local spectrum map is maintained by the target base station in the following way: the target base station receives spectrum sensing data reported by mobile terminals within its jurisdiction. The spectrum sensing data includes sensing location, sensing frequency band, received signal strength, and interference level. The target base station integrates the spectrum sensing data with the channel occupancy status collected by the target base station itself through frequency scanning according to geographical grid units to form a local spectrum map containing spatial coordinates, frequency band identifiers, and spectrum status timestamps.

[0008] Furthermore, the terminal's mobility status is obtained by the source base station in the following way: the source base station receives the global navigation satellite positioning information and mobility velocity vector periodically reported by the mobile terminal; the source base station determines the current position of the mobile terminal based on the global navigation satellite positioning information, and determines the mobile terminal's direction of movement and speed based on the mobility velocity vector, thus forming the terminal's mobility status.

[0009] Furthermore, the source base station sends a pre-planning request carrying the expected arrival time to the first non-local target base station in the pre-planned handover sequence, including: Traverse each handover node in the pre-planned handover sequence, identify the first handover node whose home base station is different from the source base station, and determine the first handover node as the first non-home base station node; The target base station is determined based on the coverage affiliation of the first non-local base station node, and the expected arrival time corresponding to the first non-local base station node is extracted from the pre-planned handover sequence. The pre-planned handover sequence and the extracted expected arrival time are encapsulated into a pre-planning request, which is then sent to the target base station through the inter-base station interface between the source base station and the target base station.

[0010] Furthermore, the target base station extracts the expected arrival time and calculates the time deviation between the expected arrival time and the most recent update time of the local spectrum map, including: The expected arrival time and pre-planned handover sequence of the first non-local base station node are parsed from the received pre-planning request; Query the maintenance log of the target base station's local spectrum map to obtain the completion time of the most recent spectrum map update operation, and use it as the most recent update time of the local spectrum map; The time deviation is obtained by calculating the time difference between the expected arrival time and the most recent update time of the local spectrum map.

[0011] Furthermore, when the time deviation exceeds a preset range, the target base station retrieves historical status records from its local spectrum map, calculates the conditional probability of failure propagation occurring in adjacent links within the pre-planned handover sequence within the time deviation, and identifies subsequent links with conditional probabilities higher than the propagation threshold as links at risk of propagation, including: Extract the links corresponding to each of two adjacent switching nodes sequentially from the pre-planned switching sequence, and take the link that is ranked first as the preceding link and the link that is ranked last as the following link to form adjacent link pairs; Obtain the set of state reversal moments of the preceding link within the time deviation from the retrieved historical state records; obtain the set of state reversal moments of the following link within the time deviation from the retrieved historical state records. The number of events in the set of state transition times of the preceding link that also result in a state transition within a preset associated time window after a state transition occurs in the set of state transition times of the preceding link is counted. The ratio of the number of events to the total number of state transitions in the set of state transition times of the preceding link is used as the conditional probability. The conditional probability is compared with a preset infection threshold, and the subsequent link in the adjacent link pair with a conditional probability higher than the infection threshold is identified as a link at risk of infection.

[0012] Furthermore, the historical status record is a sequence of status snapshots formed by storing the spectrum status data before each update in chronological order during the maintenance of the local spectrum map of the target base station. Each status snapshot in the status snapshot sequence contains the spectrum occupancy status markers of each frequency band within the coverage area of ​​the target base station at the corresponding time.

[0013] Furthermore, the target base station obtains concurrent pre-planning requests submitted by other terminals, calculates the concurrent resource contention intensity ratio for infection-risk links, and reduces the link availability confidence of infection-risk links whose concurrent resource contention intensity ratio exceeds the amplification threshold to below the confidence threshold, including: Analyze the concurrent pre-planning requests submitted by other terminals within the current processing cycle of the target base station, and extract the number of spectrum resource blocks occupied by each link in the concurrent pre-planning requests; Extract the number of spectrum resource blocks corresponding to the infectious risk links in the pre-planned handover sequence; The ratio of the number of spectrum resource blocks occupied by each link in the concurrent pre-planning request to the number of spectrum resource blocks corresponding to the contagion risk link is used as the concurrent resource contention intensity ratio. The concurrent resource contention intensity ratio is compared with a preset amplification threshold, and the link availability confidence of infection risk links whose concurrent resource contention intensity ratio exceeds the amplification threshold is reduced to below the confidence threshold.

[0014] Furthermore, the target base station replaces links with availability confidence levels below a confidence threshold with links reselected based on the current local spectrum map, forming an updated pre-planned handover sequence and performing cross-base station resource reservation, including: Identify links in the pre-planned handover sequence whose availability confidence is below the confidence threshold, and mark the identified links as links to be replaced; Select candidate links from the current local spectrum map that meet the preset channel quality threshold and whose spectrum occupancy status records are available; Based on the direction of movement in the terminal's movement state, a replacement link that connects to the link to be replaced is determined from the selected candidate links. Replace the corresponding link to be replaced in the pre-planned handover sequence with the replacement link to form an updated pre-planned handover sequence; Perform cross-base station resource reservation for each base station involved in each link in the updated pre-planned handover sequence.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. By identifying the conditional probability of failure propagation between adjacent links and determining the links at risk of propagation, the evaluation of cross-base station pre-planned paths is transformed from an isolated judgment of a single link to an analysis of the temporal coupling relationship between links. This allows the target base station to pre-mark links in the pre-planned handover sequence that are currently available but have the potential for cascading failures, based on the propagation patterns of link failures in historical state records, even when there is a state offset between the source base station's spectrum map snapshot and the target base station's local spectrum map. This avoids handover failures caused by blindly accepting pre-planned requests due to the state offset being ignored.

[0016] 2. By calculating the concurrent resource contention intensity ratio of the infection risk links, the failure infection assessment is combined with the multi-terminal concurrent contention pressure analysis. This enables the target base station to identify high-risk links that are amplified under the dual effects of failure infection and concurrent contention, and to reduce the link availability confidence of these links in a targeted manner, thereby triggering subsequent link replacement operations. The replacement links are reselected based on the current local spectrum map, and an updated pre-planned handover sequence is formed. Ultimately, the cross-base station pre-planned path is corrected and resources are reserved on the target base station side based on the latest spectrum status and contention situation, improving the reliable execution capability of the pre-planned path in a multi-base station network. Attached Figure Description

[0017] Figure 1 This is a flowchart of the radio frequency link switching path pre-planning method based on spectrum map according to the present invention; Figure 2 This is a schematic diagram of the structure of the radio frequency link switching path pre-planning system based on spectrum map according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: Figure 1 The present invention provides a pre-planning method for radio frequency link switching paths based on a spectrum map, comprising: S1. The source base station generates a pre-planned handover sequence containing the expected arrival time based on the local spectrum map and the terminal's mobility status. S2. The source base station sends a pre-planning request carrying the expected arrival time to the first non-local target base station in the pre-planned handover sequence. S3. Extract the expected arrival time from the target base station and calculate the time deviation between the expected arrival time and the latest update time of the local spectrum map. S4. When the time deviation exceeds the preset range, the target base station retrieves the historical status records of the local spectrum map, calculates the conditional probability of failure infection of adjacent links in the pre-planned handover sequence within the time deviation, and identifies the subsequent links with conditional probabilities higher than the infection threshold as infection risk links. S5. The target base station obtains concurrent pre-planning requests submitted by other terminals, calculates the concurrent resource contention intensity ratio for the infection risk links, and reduces the link availability confidence of infection risk links whose concurrent resource contention intensity ratio exceeds the amplification threshold to below the confidence threshold. S6. The target base station replaces links whose link availability confidence is lower than the confidence threshold with links reselected based on the current local spectrum map, forming an updated pre-planned handover sequence and performing cross-base station resource reservation.

[0020] In the specific implementation of S1, the source base station obtains the global navigation satellite positioning information and moving speed vector periodically reported by the mobile terminal within its jurisdiction. The global navigation satellite positioning information includes the longitude coordinates, latitude coordinates, and altitude of the mobile terminal. The moving speed vector includes the instantaneous speed and azimuth angle of the mobile terminal. The source base station determines the current position of the mobile terminal based on the global navigation satellite positioning information and determines the moving direction and moving speed of the mobile terminal based on the moving speed vector. The current position, moving direction, and moving speed of the mobile terminal are used as the terminal's moving state, wherein the moving direction is determined by the azimuth angle and the moving speed is the instantaneous speed.

[0021] The target base station receives spectrum sensing data reported by mobile terminals within its jurisdiction. The spectrum sensing data is obtained by the mobile terminals scanning a specified frequency band within a predetermined period. The spectrum sensing data includes the longitude and latitude coordinates of the sensing location, the center frequency and bandwidth of the sensing frequency band, the dBm value of the received signal strength, and the dBm value of the interference level. The target base station fuses the received spectrum sensing data with the channel occupancy status collected by the target base station itself through frequency scanning. The fusion method is to divide the coverage area of ​​the target base station into multiple equal-sized geographical grid units. Each geographical grid unit has a unique spatial coordinate identifier. The spectrum sensing data falling within the same geographical grid unit and the channel occupancy status collected by the target base station itself through frequency scanning are grouped according to the frequency band identifier. The received signal strength and interference level of the same frequency band identifier within the same geographical grid unit are averaged, and the average value is used as the spectrum status value of the geographical grid unit under the frequency band identifier.

[0022] The spectrum status value is calculated as: S = (R + I) / 2; where S represents the spectrum status value in dBm, R represents the received signal strength in dBm, and I represents the interference level in dBm. The frequency band is marked as available when the spectrum status value meets a preset availability threshold, and marked as unavailable when the spectrum status value does not meet the preset availability threshold. The preset availability threshold is calculated and set according to the minimum signal-to-interference-plus-noise ratio (SNR) requirement of communication services within the target base station's coverage area. For example, the preset availability threshold is set to a received signal strength not lower than -110 dBm and an interference level not higher than -90 dBm.

[0023] Each geographic grid cell's spatial coordinate identifier, frequency band identifier, spectrum status marker, and spectrum status timestamp at the recording time are combined to form a spectrum status record. The collection of spectrum status records of all geographic grid cells is used as a local spectrum map. The target base station stores the spectrum status data before each update of the local spectrum map in chronological order as a status snapshot sequence. Each status snapshot in the status snapshot sequence contains the spectrum occupancy status marker of each frequency band within the coverage area of ​​the target base station at the corresponding time. The status snapshot sequence serves as a historical status record.

[0024] The source base station extracts the channel quality parameters and spectrum occupancy status records of each candidate link from the local spectrum map. The candidate links are wireless links that can be accessed by mobile terminals within the coverage area of ​​the source base station and the coverage area of ​​adjacent base stations. The channel quality parameters include the received signal strength of the corresponding frequency band of the candidate link in the local spectrum map. The spectrum occupancy status records include the spectrum status mark of the corresponding frequency band of the candidate link in the local spectrum map. The source base station calculates the arrival time of the terminal to the coverage area of ​​each candidate link based on the direction and speed of the terminal's movement.

[0025] The arrival time is calculated as: Tarrive = Tcurrent + D / V; where Tarrive represents the arrival time in seconds, Tcurrent represents the current time in seconds, D represents the straight-line distance between the current location of the mobile terminal and the boundary of the candidate link coverage area in meters, V represents the moving speed in meters per second, and the current time is the local clock time when the source base station performs the calculation operation.

[0026] The source base station compares the received signal strength (RSS) of each candidate link's channel quality parameters with a preset channel quality threshold. This threshold is set based on the minimum RSS requirement for the communication service type within the target base station's coverage area. For example, the preset threshold is set to -115 dBm for enhanced mobile broadband services and -105 dBm for ultra-reliable low-latency communication services within the target base station's coverage area. The source base station identifies candidate links that meet the preset channel quality threshold and whose spectrum status is marked as available in the spectrum occupancy record as handover nodes. These handover nodes are then connected in series according to the terminal's direction of movement. The series connection is based on the distance between the handover nodes and the terminal's movement direction, from closest to furthest. The arrival time of each handover node is used as the expected arrival time, forming a pre-planned handover sequence containing multiple handover nodes and their corresponding expected arrival times. Each handover node in the pre-planned handover sequence corresponds to an expected arrival time.

[0027] The target base station records the completion time of the update operation and writes it to the maintenance log each time it updates the local spectrum map. The maintenance log saves the completion times of the most recent update operations. The completion time of the most recent update operation is the most recent update time of the local spectrum map. The update cycle is consistent with the shorter of the cycle of the target base station receiving spectrum sensing data from mobile terminals and the target base station's own frequency scanning cycle.

[0028] In the specific implementation of S2, after generating a pre-planned handover sequence containing multiple handover nodes and their corresponding expected arrival times, the source base station traverses each handover node in the pre-planned handover sequence and checks the coverage home base station corresponding to each handover node one by one. The coverage home base station is the base station to which the link corresponding to the handover node belongs. The coverage home base station of each handover node is recorded in the correspondence between geographical grid cells and base stations when the local spectrum map is formed. This correspondence is established when the target base station divides the coverage area into geographical grid cells. The spatial coordinate identifier of each geographical grid cell is associated with a home base station identifier. The source base station compares the coverage home base station of each handover node with the base station identifier of the source base station, identifies the first handover node whose coverage home base station is different from the base station identifier of the source base station, and determines the first handover node that is not a node of this base station.

[0029] The source base station determines the target base station based on the coverage home base station of the first non-local node. The target base station is the coverage home base station of the first non-local node. After determining the target base station, the source base station extracts the expected arrival time corresponding to the first non-local node from the pre-planned handover sequence. The extraction method is to obtain the sequence number of the first non-local node in the pre-planned handover sequence and read the expected arrival time corresponding to that sequence number in the pre-planned handover sequence.

[0030] The source base station encapsulates the pre-planned handover sequence and the extracted expected arrival times into a pre-planning request. The pre-planning request consists of two parts: the first part contains all handover nodes in the pre-planned handover sequence and the expected arrival time for each handover node; the second part is a separate field for the expected arrival time of the first node not belonging to this base station. This separate field is used by the target base station for direct parsing without traversing the pre-planned handover sequence. After encapsulation, the source base station queries the interface type and address of the inter-base station interface between itself and the target base station. The inter-base station interface is the logical communication interface used between the source and target base stations for exchanging handover signaling messages and resource negotiation messages. For example, the inter-base station interface is the Xn or X2 interface defined in the 3GPP standard. The source base station sends the pre-planning request to the target base station in the form of a signaling message through the inter-base station interface. When sending, the target base station's base station identifier is used as the destination address of the signaling message, and the source base station's base station identifier is used as the source address of the signaling message.

[0031] In the specific implementation of S3, the target base station receives the pre-planning request signaling message sent by the source base station through the inter-base station interface, and parses out the two components of the pre-planning request from the pre-planning request signaling message. The first part of the pre-planning request is all the handover nodes in the pre-planned handover sequence and the expected arrival time of each handover node. The second part is an independent field for the expected arrival time of the first non-local base station node. The target base station directly reads the expected arrival time of the first non-local base station node from the independent field, and simultaneously extracts the pre-planned handover sequence from the first part.

[0032] The target base station queries the maintenance log of its local spectrum map. The maintenance log is a file recorded by the target base station each time it updates the local spectrum map. The log contains the completion time of each update operation, recorded based on the target base station's local clock, in a timestamp format of year, month, day, hour, minute, second, and millisecond. The target base station retrieves the most recent update record from the maintenance log, reads the completion time of the update operation recorded in that record, and uses this read completion time as the most recent update time of its local spectrum map.

[0033] The target base station calculates the time difference between the expected arrival time of the first non-base station node and the most recent update time of the local spectrum map. The time deviation is calculated as: ΔT = Tarrivetarget − Tupdate; where ΔT represents the time deviation in seconds, Tarrivetarget represents the expected arrival time of the first non-base station node in seconds, and Tupdate represents the most recent update time of the local spectrum map in seconds. When ΔT is positive, it indicates that the expected arrival time of the first non-base station node is later than the most recent update time of the local spectrum map; when ΔT is negative, it indicates that the expected arrival time of the first non-base station node is earlier than the most recent update time of the local spectrum map.

[0034] The target base station compares the absolute value of the time deviation with a preset deviation threshold. The preset deviation threshold is set based on the average handover execution time of the mobile terminal within the coverage area of ​​the target base station. The average handover execution time is the average of the time elapsed from the triggering of the handover decision to the completion of the handover, as statistically analyzed by the target base station based on historical handover records. For example, if the average handover execution time is 50 milliseconds, then the preset deviation threshold is set to 50 milliseconds.

[0035] The preset range refers to a numerical interval greater than zero and less than or equal to a preset deviation threshold. When the absolute value of the time deviation falls within the preset range, it indicates that the state offset between the spectrum state snapshot on which the source base station generates the pre-planned handover sequence and the local spectrum map currently maintained by the target base station is within an acceptable range. A time deviation exceeding the preset range means that the absolute value of the time deviation is greater than the preset deviation threshold. When the absolute value of the time deviation is greater than the preset deviation threshold, it indicates that there is a non-negligible state offset between the spectrum state snapshot on which the source base station generates the pre-planned handover sequence and the local spectrum map currently maintained by the target base station, requiring the initiation of the subsequent failure propagation assessment process.

[0036] In a specific implementation of S4, when the time deviation exceeds the preset range, the target base station initiates a failure propagation assessment process for the pre-planned handover sequence.

[0037] The target base station extracts adjacent handover nodes sequentially from the pre-planned handover sequence, according to the order of the handover nodes. For each pair of adjacent handover nodes, the target base station obtains the link corresponding to the first handover node in the sequence as the preceding link and the link corresponding to the second handover node in the sequence as the following link. The preceding and following links are then combined into a pair of adjacent links. This process is repeated for all adjacent handover nodes in the pre-planned handover sequence, resulting in several pairs of adjacent link pairs. The correspondence between handover nodes and links is determined when the source base station generates the pre-planned handover sequence. Each handover node corresponds to a candidate link, which is uniquely identified by its base station identifier and frequency band identifier.

[0038] The target base station retrieves historical status records from its local spectrum map. These historical status records are a sequence of snapshots created by the target base station during the maintenance of its local spectrum map, storing spectrum status data in chronological order before each update. Each snapshot contains a spectrum occupancy status marker for each frequency band within the target base station's coverage area at the corresponding time. These markers include both available and unavailable values. The target base station then obtains the timestamp range of the snapshots from the historical records, extracting all snapshots whose timestamps fall within the time range from the most recent update of the local spectrum map to the expected arrival time of the first non-local base station node.

[0039] For each pair of adjacent links, the target base station extracts the state flip time sets for the preceding link and the following link from the captured state snapshots. The preceding link state flip time set is extracted by iterating through the captured state snapshots and comparing the spectrum occupancy status markers of the corresponding frequency bands of the preceding link in chronological order between two adjacent state snapshots. When the spectrum occupancy status marker of the corresponding frequency band of the preceding link changes from an available marker to an unavailable marker in two adjacent state snapshots, the time corresponding to the changed state snapshot is recorded as a state flip time for the preceding link. The set of all state flip times is used as the preceding link state flip time set. Similarly, the following method is used to extract the following state flip time set: traversing the captured state snapshots and comparing the spectrum occupancy status markers of the corresponding frequency bands of the following link in chronological order between two adjacent state snapshots. When the spectrum occupancy status marker of the corresponding frequency band of the following link changes from an available marker to an unavailable marker in two adjacent state snapshots, the time corresponding to the changed state snapshot is recorded as a state flip time for the following link. The set of all state flip times is used as the following link state flip time set.

[0040] The target base station counts the number of events in the set of state flip times for the preceding link that also result in a state flip within a preset associated time window after a state flip has occurred in the set of state flip times for the preceding link. The counting method involves iterating through each state flip time in the set of state flip times for the preceding link. For each state flip time in the preceding link, it checks if there is a state flip time in the set of state flip times for the following duration (from the state flip time of the preceding link to the duration of the state flip time plus the preset associated time window). If such a time exists, the event count is incremented by one.

[0041] The preset association time window is set based on the statistical value of the wireless channel coherence time within the coverage area of ​​the target base station. The wireless channel coherence time is the length of time during which the characteristics of the wireless channel remain approximately unchanged. For example, in a walking speed scenario at 2.4 GHz, the wireless channel coherence time is approximately 20 milliseconds, so the preset association time window is set to 20 milliseconds. The significance of setting the preset association time window is that if the state flip of the downstream link occurs within one wireless channel coherence time after the state flip of the upstream link, it indicates that the state changes of the upstream and downstream links are triggered by the same propagation environment change event, and there is a real failure contagion relationship, rather than a random overlap in time.

[0042] The target base station divides the number of events by the total number of state transitions in the previous link's state transition time set to obtain the conditional probability. The conditional probability is calculated as: P = Nco / Ntotal; where P represents the conditional probability, which is dimensionless and ranges from 0 to 1; Nco represents the number of events in the previous link's state transition time set that also result in a state transition within a preset associated time window after a state transition occurs, in units of times; and Ntotal represents the total number of state transitions in the previous link's state transition time set, in units of times.

[0043] The target base station compares the conditional probability with a preset infection threshold. The preset infection threshold is set based on statistical analysis of historical wireless link status data within the target base station's coverage area. The method involves statistically analyzing the conditional probability values ​​of all adjacent link pairs within the target base station's coverage area over a past period, sorting the conditional probability values ​​from low to high, and taking the conditional probability value at the boundary between the first quartile and the last third of the sorted value as the preset infection threshold. For example, if the spectrum status data from the past 7 days is statistically analyzed, and the conditional probability distribution of all adjacent link pairs is calculated, and the conditional probability value corresponding to the upper quartile is 0.3, then the preset infection threshold is set to 0.3. When the conditional probability is higher than the preset infection threshold, it indicates a statistically significant failure infection relationship between the preceding and following links. The failure of the preceding link will trigger the failure of the following link within a preset association time window with a higher probability than random. The target base station identifies the following link among the adjacent link pairs with conditional probabilities higher than the preset infection threshold as infection-risk links.

[0044] By assessing failure contagion, the target base station identifies which links in the pre-planned handover sequence, although their own spectrum status appears available in the current local spectrum map, are at risk of being triggered by the failure of the preceding link due to a significant failure contagion relationship with it. This analytical perspective overcomes the shortcomings of traditional handover path assessment, which only focuses on the current spectrum status of a single link and ignores the temporal failure coupling between links.

[0045] In a specific implementation of S5, after the target base station has determined the infection risk link, it initiates a concurrent contention amplification evaluation process for the infection risk link.

[0046] The target base station acquires concurrent pre-planning requests submitted by other terminals to the target base station within the current processing cycle. These concurrent pre-planning requests are requests sent by mobile terminals other than the current mobile terminal within the target base station's current processing cycle. The current processing cycle is the time period from when the target base station receives the pre-planning request from the source base station until it executes cross-base station resource reservation. The target base station parses each concurrent pre-planning request and extracts the number of spectrum resource blocks occupied by each link within the pre-planned handover sequence carried in each request. The number of spectrum resource blocks represents the minimum scheduling unit of frequency domain resources required by each link in the pre-planned handover sequence. The value of the number of spectrum resource blocks is determined by the frequency band bandwidth and resource block configuration parameters corresponding to the link in the concurrent pre-planning request. The resource block configuration parameters include subcarrier spacing and the number of physical resource blocks.

[0047] The target base station extracts the number of spectrum resource blocks corresponding to the infection risk links from the pre-planned handover sequence of the current mobile terminal. The infection risk links have been identified in S4, and each infection risk link corresponds to a frequency band identifier in the pre-planned handover sequence. Based on the frequency band identifier corresponding to the infection risk link, the target base station reads the resource block configuration parameters corresponding to that frequency band identifier and uses the number of physical resource blocks as the number of spectrum resource blocks corresponding to the infection risk link.

[0048] The target base station calculates the concurrent resource contention intensity ratio. For each contagion-risk link, the target base station sums the number of spectrum resource blocks occupied by each link in all concurrent pre-planning requests to obtain the total concurrent spectrum resource demand. The ratio of the total concurrent spectrum resource demand to the number of spectrum resource blocks corresponding to the contagion-risk link is used as the concurrent resource contention intensity ratio. The concurrent resource contention intensity ratio is calculated as: C = Rconcurrent / Rrisk; where C represents the concurrent resource contention intensity ratio, which is dimensionless; Rconcurrent represents the sum of the number of spectrum resource blocks occupied by each link in all concurrent pre-planning requests, in units of blocks; and Rrisk represents the number of spectrum resource blocks corresponding to the contagion-risk link, in units of blocks. The concurrent resource contention intensity ratio reflects the degree of resource contention pressure faced by the contagion-risk link. The larger the concurrent resource contention intensity ratio, the more concurrent pre-planning requests compete with the contagion-risk link for the same spectrum resource blocks, and the greater the threat to the resource availability of the contagion-risk link.

[0049] The target base station compares the concurrent resource contention intensity ratio with a preset amplification threshold. The preset amplification threshold is set based on the statistical characteristics of the historical concurrent resource contention intensity ratio of infected risk links during normal handover execution. The method involves statistically analyzing the concurrent resource contention intensity ratio of infected risk links within the target base station's coverage area over a past period under normal handover execution. The average concurrent resource contention intensity ratio is then added to twice the standard deviation to obtain the preset amplification threshold. For example, if the average concurrent resource contention intensity ratio for the past 7 days is 1.2 and the standard deviation is 0.4, then the preset amplification threshold is set to 2.0. When the concurrent resource contention intensity ratio exceeds the preset amplification threshold, it indicates that the resource contention pressure currently faced by the infected risk link is significantly higher than normal. The concurrent contention has amplified the infected risk link, transforming the potential risk that was originally only due to failure transmission into actual resource contention pressure under the current concurrent contention conditions, further deteriorating the availability of the infected risk link.

[0050] When the concurrent resource contention intensity ratio exceeds a preset amplification threshold, the target base station reduces the link availability confidence of the link at risk of infection to below a confidence threshold. The link availability confidence is the target base station's assessment of the actual availability of each link in the pre-planned handover sequence. Each link is assigned an initial link availability confidence when the source base station generates the pre-planned handover sequence. This initial link availability confidence is set based on the margin between the received signal strength of the link in the local spectrum map and a preset channel quality threshold. For example, if the received signal strength exceeds the preset channel quality threshold by 5dB, the initial link availability confidence is set to 0.9. The confidence threshold is a lower limit of the link availability confidence set based on the minimum link reliability requirements of communication services within the target base station's coverage area. For example, the confidence threshold is set to 0.6 when carrying enhanced mobile broadband services within the target base station's coverage area, and 0.8 when carrying ultra-reliable low-latency communication services. The target base station will forcibly adjust the link availability confidence of infection risk links whose concurrent resource contention intensity exceeds a preset amplification threshold to a value below the confidence threshold, such as directly adjusting it to 0, so that the infection risk link will inevitably be identified as a link to be replaced in the subsequent replacement process.

[0051] Through concurrent contention amplification assessment, the target base station further filters out the infection risk links affected by the amplification effect under concurrent contention pressure from the infection risk links determined by S4. These infection risk links not only have a failure infection relationship with the previous link, but also face resource contention pressure from other terminals' concurrent pre-planning requests in the current processing cycle, exhibiting the characteristics of dual risk superposition. This makes up for the shortcomings of traditional handover path assessment, which only considers the resource requirements of a single terminal and ignores the asymmetric pressure generated by the concurrent contention of multiple terminals on specific vulnerable links.

[0052] In the specific implementation of S6, the target base station performs link replacement and cross-base station resource reservation processes for each link in the pre-planned handover sequence.

[0053] The target base station checks the link availability confidence of each link in the pre-planned handover sequence one by one and compares the link availability confidence with a confidence threshold. When the link availability confidence is lower than the confidence threshold, the target base station marks the link as a link to be replaced. The link availability confidence has been updated in S4 and S5. After the concurrency contention amplification assessment, the link availability confidence of a link at risk of infection may have been reduced to below the confidence threshold. The initial value of the link availability confidence is set when the source base station generates the pre-planned handover sequence. The initial link availability confidence is set according to the difference between the received signal strength of the link in the local spectrum map and the preset channel quality threshold. The setting method is that for every 1dB increase in the difference between the received signal strength and the preset channel quality threshold, the initial link availability confidence increases by 0.1 from the base value, which is set to 0.5. The upper limit of the initial link availability confidence is 1.0. For example, when the received signal strength exceeds the preset channel quality threshold by 5dB, the initial link availability confidence is set to 0.5 + 0.5 = 1.0. The confidence threshold is set according to the minimum link reliability requirements of communication services within the coverage area of ​​the target base station. For example, the confidence threshold is set to 0.6 when carrying enhanced mobile broadband services within the coverage area of ​​the target base station, and to 0.8 when carrying ultra-reliable low-latency communication services.

[0054] For each link to be replaced, the target base station selects candidate links for replacement from the current local spectrum map. The current local spectrum map is the latest local spectrum map maintained by the target base station at the time of the replacement operation, and has updated spectrum status information compared with the spectrum snapshot used by the source base station when generating the pre-planned handover sequence. The target base station traverses all frequency band identifiers within the geographic grid cells corresponding to the coverage area of ​​the link to be replaced from the current local spectrum map, extracting the channel quality parameters and spectrum occupancy status records corresponding to each frequency band identifier. The channel quality parameters include received signal strength, and the spectrum occupancy status records include spectrum status markers. The target base station identifies frequency band identifiers whose received signal strength meets the preset channel quality threshold and whose spectrum status markers show as available as candidate links. The preset channel quality threshold is consistent with the preset channel quality threshold used by the source base station when determining the handover node in S1.

[0055] The target base station determines the replacement link from the selected candidate links based on the direction of movement in the terminal's mobility status. The terminal's mobility status is obtained by the source base station in S1 based on the global navigation satellite positioning information and velocity vector periodically reported by the mobile terminal. The source base station encapsulates the terminal's mobility status in the second part of the pre-planning request and sends it to the target base station. The target base station parses the terminal's mobility status from the pre-planning request to obtain the mobile terminal's direction of movement. The target base station determines the replacement link by searching for candidate links whose coverage areas are continuously covered in the direction of movement between the candidate link's coverage area and the coverage areas of the preceding and following switching nodes of the link to be replaced, at the pre-planned handover sequence position of the link to be replaced. Continuous coverage means that the front boundary of the candidate link's coverage area is within the coverage area of ​​the preceding switching node of the link to be replaced in the direction of movement, and the rear boundary of the candidate link's coverage area is within the coverage area of ​​the following switching node of the link to be replaced in the direction of movement. When multiple candidate links simultaneously meet the continuous coverage condition, the target base station selects the candidate link with the highest received signal strength as the replacement link.

[0056] The target base station will replace the corresponding link to be replaced in the pre-planned handover sequence with a replacement link. The replacement method is to delete the handover node corresponding to the link to be replaced in the pre-planned handover sequence, insert a new handover node corresponding to the replacement link in the original position of the link to be replaced, and set the expected arrival time of the new handover node corresponding to the replacement link to the original expected arrival time of the link to be replaced. Keep the other unreplaced handover nodes in the pre-planned handover sequence and their corresponding expected arrival times unchanged, thus forming an updated pre-planned handover sequence.

[0057] The target base station performs cross-base station resource reservation for each link involved in the updated pre-planned handover sequence. The target base station traverses each handover node in the updated pre-planned handover sequence, identifying the base station to which the link belongs for each handover node. When the base station to which the link belongs is the target base station, the target base station performs resource reservation locally. When the base station to which the link belongs is another base station, the target base station sends a resource reservation request to that other base station through the inter-base station interface. The resource reservation request carries the frequency band identifier of the link to be reserved and the reservation time window. The reservation time window is determined based on the expected arrival time of the corresponding handover node and the expected dwell time of the link. The expected dwell time is the expected dwell time of the mobile terminal within the link coverage area, calculated by dividing the length of the link coverage area in the direction of movement by the moving speed. Each base station, based on the received resource reservation request, locks the spectrum resources of the corresponding frequency band identifier within the corresponding reservation time window, completing the cross-base station resource reservation for all links in the updated pre-planned handover sequence.

[0058] Example 2: Figure 2 A schematic diagram of the RF link handover path pre-planning system based on a spectrum map according to the present invention is provided. The RF link handover path pre-planning system based on a spectrum map includes: The sequence generation module is used by the source base station to generate a pre-planned handover sequence containing the expected arrival time based on the local spectrum map and the terminal's mobility status. The request sending module is used by the source base station to send a pre-planned request carrying the expected arrival time to the first non-local target base station in the pre-planned handover sequence. The deviation calculation module is used to extract the expected arrival time from the target base station and calculate the time deviation between the expected arrival time and the most recently updated time of the local spectrum map. The infection assessment module is used to retrieve the historical status records of the local spectrum map of the target base station when the time deviation exceeds the preset range, calculate the conditional probability of failure infection of adjacent links in the pre-planned handover sequence within the time deviation, and identify the subsequent links with conditional probabilities higher than the infection threshold as infection risk links. The contention amplification module is used by the target base station to obtain concurrent pre-planning requests submitted by other terminals, calculate the concurrent resource contention intensity ratio for the infection risk links, and reduce the link availability confidence of infection risk links whose concurrent resource contention intensity ratio exceeds the amplification threshold to below the confidence threshold. The link replacement module is used by the target base station to replace links whose link availability confidence is lower than the confidence threshold with links reselected based on the current local spectrum map, forming an updated pre-planned handover sequence and performing cross-base station resource reservation.

[0059] All calculations involved in the embodiments are performed using dimensionless numerical values, and the preset parameters and thresholds in the calculations can be set by those skilled in the art according to actual conditions.

[0060] This technical solution can be flexibly deployed, for example, as embedded software running on device hardware, or installed on personal computers or other smart terminals with user interfaces, thus adapting to various hardware environments and usage requirements.

[0061] The above solutions can be implemented in software, hardware, firmware, or a combination thereof. When implemented in software, they are presented, in whole or in part, as a computer program product, containing one or more computer instructions or programs. When these instructions or programs are loaded and executed on a computer, results are produced corresponding to the processes or functions of the embodiments of this application. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. Computer instructions can be stored in a computer-readable storage medium or transmitted from one medium to another via wired or wireless means, such as from a website, server, or data center via wired means such as fiber optic cables, twisted-pair cables, or coaxial cables, or wireless means such as infrared or microwaves to another site. A computer-readable storage medium refers to any usable medium that a computer can access or a data storage device such as a server or data center that contains one or more usable media, including magnetic media such as floppy disks, hard disks, and magnetic tapes, optical media such as DVDs, and semiconductor media such as solid-state drives.

[0062] The specific working process of the system, device and module can be found in the method embodiment, and will not be repeated here.

[0063] The disclosed systems, devices, and methods can be implemented in other ways. The device embodiments are for illustrative purposes only, and the module division is only a logical division. In practice, different divisions can be implemented, such as merging or integrating multiple modules or components, or omitting some features. Coupling, direct coupling, or communication connections between the components can be achieved through interfaces, while indirect coupling or communication connections can take electrical, mechanical, or other forms.

[0064] The modules described as separate components may or may not be physically separated. The components shown as modules can be physical hardware or software, and can be deployed centrally or distributed across multiple network nodes. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0065] The functional modules in each embodiment can be integrated into one processing module, or they can exist independently, or two or more modules can be integrated into one.

[0066] If the functionality is implemented as a software module and used as an independent product, it can be stored in a computer-readable storage medium. Under this understanding, the substantial contribution of the technical solution of this application can be embodied in the form of a software product. This computer software product is stored in a storage medium and contains instructions to cause a computer device, such as a personal computer, server, or network device, to execute all or part of the steps of the methods in the embodiments of this application. The storage medium includes any medium capable of storing program code, such as a USB flash drive, portable hard drive, read-only memory, random access memory, magnetic disk, or optical disk.

[0067] The above are merely specific embodiments of this application, and the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should fall within the scope of protection of this application.

Claims

1. A method for pre-planning radio frequency link switching paths based on spectrum maps, characterized in that, include: S1. The source base station generates a pre-planned handover sequence containing the expected arrival time based on the local spectrum map and the terminal's mobility status. S2. The source base station sends a pre-planning request carrying the expected arrival time to the first non-local target base station in the pre-planned handover sequence. S3. Extract the expected arrival time from the target base station and calculate the time deviation between the expected arrival time and the latest update time of the local spectrum map. S4. When the time deviation exceeds the preset range, the target base station retrieves the historical status records of the local spectrum map, calculates the conditional probability of failure infection of adjacent links in the pre-planned handover sequence within the time deviation, and identifies the subsequent links with conditional probabilities higher than the infection threshold as infection risk links. S5. The target base station obtains concurrent pre-planning requests submitted by other terminals, calculates the concurrent resource contention intensity ratio for the infection risk links, and reduces the link availability confidence of infection risk links whose concurrent resource contention intensity ratio exceeds the amplification threshold to below the confidence threshold. S6. The target base station replaces links whose link availability confidence is lower than the confidence threshold with links reselected based on the current local spectrum map, forming an updated pre-planned handover sequence and performing cross-base station resource reservation.

2. The method for pre-planning radio frequency link switching paths based on a spectrum map according to claim 1, characterized in that, The source base station generates a pre-planned handover sequence containing the expected arrival time based on the local spectrum map and terminal mobility status, including: Extract the channel quality parameters and spectrum occupancy status records of each candidate link from the local spectrum map; The arrival time of the terminal to the coverage area of ​​each candidate link is estimated based on the direction and speed of movement in the terminal's movement state. Candidate links that meet the preset channel quality threshold and whose spectrum occupancy status is recorded as available are identified as switching nodes; The handover nodes are connected in series according to the direction of terminal movement, and the arrival time of each handover node is taken as the expected arrival time, forming a pre-planned handover sequence that includes multiple handover nodes and their corresponding expected arrival times.

3. The method for pre-planning radio frequency link switching paths based on a spectrum map according to claim 2, characterized in that, The local spectrum map is maintained by the target base station in the following way: The target base station receives spectrum sensing data reported by mobile terminals within its jurisdiction. The spectrum sensing data includes sensing location, sensing frequency band, received signal strength and interference level. The target base station merges the spectrum sensing data with the channel occupancy status collected by the target base station itself by frequency scanning according to geographical grid units to form a local spectrum map containing spatial coordinates, frequency band identifiers and spectrum status timestamps.

4. The method for pre-planning radio frequency link switching paths based on a spectrum map according to claim 2, characterized in that, The terminal's mobility status is obtained by the source base station in the following way: the source base station receives the global navigation satellite positioning information and mobility velocity vector periodically reported by the mobile terminal; the source base station determines the current position of the mobile terminal based on the global navigation satellite positioning information, and determines the mobile terminal's direction of movement and speed based on the mobility velocity vector, thus forming the terminal's mobility status.

5. The method for pre-planning radio frequency link switching paths based on a spectrum map according to claim 1, characterized in that, The source base station sends a pre-planning request carrying the expected arrival time to the first non-local target base station in the pre-planned handover sequence, including: Traverse each handover node in the pre-planned handover sequence, identify the first handover node whose home base station is different from the source base station, and determine the first handover node as the first non-home base station node; The target base station is determined based on the coverage affiliation of the first non-local base station node, and the expected arrival time corresponding to the first non-local base station node is extracted from the pre-planned handover sequence. The pre-planned handover sequence and the extracted expected arrival time are encapsulated into a pre-planning request, which is then sent to the target base station through the inter-base station interface between the source base station and the target base station.

6. The method for pre-planning radio frequency link switching paths based on a spectrum map according to claim 1, characterized in that, The target base station extracts the expected arrival time and calculates the time deviation between the expected arrival time and the most recent update time of the local spectrum map, including: The expected arrival time and pre-planned handover sequence of the first non-local base station node are parsed from the received pre-planning request; Query the maintenance log of the target base station's local spectrum map to obtain the completion time of the most recent spectrum map update operation, and use it as the most recent update time of the local spectrum map; The time deviation is obtained by calculating the time difference between the expected arrival time and the most recent update time of the local spectrum map.

7. The method for pre-planning radio frequency link switching paths based on a spectrum map according to claim 1, characterized in that, When the time deviation exceeds a preset range, the target base station retrieves historical status records from its local spectrum map, calculates the conditional probability of failure propagation occurring in adjacent links within the pre-planned handover sequence within the time deviation, and identifies subsequent links with conditional probabilities higher than the propagation threshold as links at risk of propagation, including: Extract the links corresponding to each of two adjacent switching nodes sequentially from the pre-planned switching sequence, and take the link that is ranked first as the preceding link and the link that is ranked last as the following link to form adjacent link pairs; Obtain the set of state reversal moments of the preceding link within the time deviation from the retrieved historical state records; obtain the set of state reversal moments of the following link within the time deviation from the retrieved historical state records. The number of events in the set of state transition times of the preceding link that also result in a state transition within a preset associated time window after a state transition occurs in the set of state transition times of the preceding link is counted. The ratio of the number of events to the total number of state transitions in the set of state transition times of the preceding link is used as the conditional probability. The conditional probability is compared with a preset infection threshold, and the subsequent link in the adjacent link pair with a conditional probability higher than the infection threshold is identified as a link at risk of infection.

8. The method for pre-planning RF link switching paths based on a spectrum map according to claim 7, characterized in that, Historical status records are a sequence of status snapshots formed by storing the spectrum status data before each update in chronological order during the maintenance of the local spectrum map of the target base station. Each status snapshot in the status snapshot sequence contains the spectrum occupancy status markers of each frequency band within the coverage area of ​​the target base station at the corresponding time.

9. The method for pre-planning radio frequency link switching paths based on a spectrum map according to claim 1, characterized in that, The target base station obtains concurrent pre-planning requests submitted by other terminals, calculates the concurrent resource contention intensity ratio for infection-risk links, and reduces the link availability confidence of infection-risk links whose concurrent resource contention intensity ratio exceeds the amplification threshold to below the confidence threshold, including: Analyze the concurrent pre-planning requests submitted by other terminals within the current processing cycle of the target base station, and extract the number of spectrum resource blocks occupied by each link in the concurrent pre-planning requests; Extract the number of spectrum resource blocks corresponding to the infectious risk links in the pre-planned handover sequence; The ratio of the number of spectrum resource blocks occupied by each link in the concurrent pre-planning request to the number of spectrum resource blocks corresponding to the contagion risk link is used as the concurrent resource contention intensity ratio. The concurrent resource contention intensity ratio is compared with a preset amplification threshold, and the link availability confidence of infection risk links whose concurrent resource contention intensity ratio exceeds the amplification threshold is reduced to below the confidence threshold.

10. The method for pre-planning radio frequency link switching paths based on a spectrum map according to claim 1, characterized in that, The target base station replaces links with availability confidence levels below a confidence threshold with links reselected based on the current local spectrum map, forming an updated pre-planned handover sequence and performing cross-base station resource reservation, including: Identify links in the pre-planned handover sequence whose availability confidence is below the confidence threshold, and mark the identified links as links to be replaced; Select candidate links from the current local spectrum map that meet the preset channel quality threshold and whose spectrum occupancy status records are available; Based on the direction of movement in the terminal's movement state, a replacement link that connects to the link to be replaced is determined from the selected candidate links. Replace the corresponding link to be replaced in the pre-planned handover sequence with the replacement link to form an updated pre-planned handover sequence; Perform cross-base station resource reservation for each base station involved in each link in the updated pre-planned handover sequence.

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