Method for asynchronous subnet fusion in 5G access and backhaul integrated system

Abstract

The invention discloses a method for asynchronous subnet fusion in a 5G access and return integrated system, and relates to the field of 5G communication. According to the method, firstly, a plurality of independent subnets with different frame boundaries are formed, then each node sets a synchronization signal measurement interval MG of the node, synchronization signals of different-step subnets are detected in the synchronization signal measurement interval MG of the node, the relation between a master subnet and a slave subnet between the two subnets is determined according to detected different-step subnet information, and the synchronization signals of the master subnet and the slave subnet are determined according to the relation between the master subnet and the slave subnet. The main subnet continues to detect the asynchronous subnets, and the subordinate subnets are fused into the main subnet and continue to detect the asynchronous subnets until all the asynchronous subnets are fused. According to the method, the success rate of mutual detection of asynchronous nodes is effectively ensured by defining a dynamic synchronous signal measurement window; and the method has very important significance for multi-node service intercommunication in a special application scene without a unified clock source.

Description

Technical Field

[0001] The present invention relates to the field of 5G communications, and in particular to a method for asynchronous subnet fusion in a 5G access and backhaul integrated system. Background Art

[0002] In the 5G access and backhaul integrated network based on the time division system, each node contains the functions of 5GC and gNB. The nodes use the same spectrum resources through time division multiplexing to achieve mutual self-organizing network communication connection and form a self-organizing network. The 5G access and backhaul integrated network itself does not rely on the mobile communication network supported by fixed infrastructure. It has the characteristics of being decentralized, self-organizing, flexible network topology, and strong anti-destruction. The synchronization between nodes in the network depends on a unified satellite synchronization source and the delay measurement and clock adjustment of the data link between nodes under the dynamic topology to achieve high-precision synchronization between nodes. In the absence of a unified satellite synchronization source, the wireless self-organizing network nodes can generate a subnet head node (master node). When other nodes access the network, they can directly (single hop) or indirectly (multi-hop) synchronize with the subnet head node (master node) time, so as to achieve clock self-synchronization between nodes in a single subnet based on the local clock of the head node (master node).

[0003] In the time-division 5G access and backhaul integrated self-organizing network system, if multiple independent subnets with different frame boundaries are initially formed in the network, after the nodes in the subnet complete the initial synchronization, all time slots are used for the service transmission of the 5G access waveform or the service transmission of the self-organizing network waveform between nodes, and the full-time synchronization signal detection process at the time of network access is no longer performed. Then, when two subnets with different time slot boundaries approach each other during movement, they will not be able to detect each other to form a unified network, and the strong interference generated between the nodes of the two gradually approaching subnets will seriously affect the normal transmission of the corresponding node access service and the self-organizing network service, resulting in service interruption.

[0004] How to enable a connected ad hoc network node to detect another subnet whose frame boundaries are completely misaligned and trigger the fusion of asynchronous subnets is of great significance for multi-node service interoperability in special application scenarios without a unified clock source. Summary of the invention

[0005] In view of this, the present invention proposes a method for integrating asynchronous subnets in a 5G access and backhaul integrated system, which solves the problem of unified networking of asynchronous subnets in wireless ad hoc networks in scenarios without a unified clock synchronization source.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for asynchronous subnet fusion in a 5G access backhaul integrated system is applied to the fusion of asynchronous subnets without a unified satellite synchronization source, comprising the following steps:

[0008] Step 1: Each node performs initial access and intra-subnet synchronization, thereby forming multiple independent subnets with different frame boundaries;

[0009] Step 2, each node sets its own synchronization signal measurement interval MG, and detects the synchronization signal of the asynchronous subnet within its own synchronization signal measurement interval MG; if the synchronization signal of the asynchronous subnet is detected, step 3 is executed, otherwise, step 2 is continued;

[0010] Step 3: If the detected synchronization signal of the asynchronous subnet is an NR access waveform synchronization signal, execute step 4; if it is an ad hoc network waveform synchronization signal, execute step 5;

[0011] Step 4, obtaining the clock frame boundary of the asynchronous subnet, calculating the sending time slot position of the self-organizing network waveform synchronization signal of the asynchronous subnet, and detecting the self-organizing network waveform synchronization signal of the asynchronous subnet at the time slot position;

[0012] Step 5: According to the received self-organizing network waveform synchronization signal of the asynchronous subnet, the subnet clock information, subnet master node information and the number of nodes in the subnet of the asynchronous subnet are obtained;

[0013] Step 6, compare the subnet scale and master node number of the subnet where the current node is located with the asynchronous subnet, and determine the relationship between the master subnet and the slave subnet, where the master subnet continues to execute step 2, and the slave subnet merges into the master subnet, and then continues to execute step 2 until all asynchronous subnets are merged.

[0014] Furthermore, the specific method of step 1 is:

[0015] Each node performs synchronization signal detection for the entire period. If it detects the self-organizing network waveform synchronization signal of one or more neighboring nodes, and these self-organizing network waveform synchronization signals indicate that the number of nodes in the subnet is 1, the node with the smallest node number is selected as the master node, and then initiates the synchronization handshake process with the master node to synchronize the clock of this node with the clock of the master node;

[0016] If it is detected that the self-organizing network waveform synchronization signal of the neighboring node indicates that the number of nodes in the subnet is greater than 1, the synchronization process with the neighboring node is initiated to synchronize the clock of this node with the clock of the neighboring node, thereby forming a subnet with aligned frame boundaries. Nodes in different geographical areas are synchronously interconnected to form multiple independent subnets with different frame boundaries.

[0017] Furthermore, in step 2, each node sets its own synchronization signal measurement interval MG in the following specific manner:

[0018] For the current 5G access backhaul integrated system, the sending period of the NR access waveform synchronization signal is recorded as J milliseconds, and the sending period of the ad hoc network waveform synchronization signal is recorded as K milliseconds. Then the total width of the synchronization signal measurement interval MG is set to S milliseconds, S = MIN (J, K) + synchronization signal sending time width;

[0019] Set the asynchronous subnet measurement period P:

[0020] P = static_offset * N;

[0021] Wherein, N represents dividing the synchronization signal measurement interval MG within an asynchronous subnet measurement large cycle P into N measurement small windows, static_offset represents the sub-cycle occupied by each measurement small window, and the value of static_offset is an integer multiple of MIN(J, K);

[0022] The width of each small measurement window is L milliseconds + synchronization signal transmission time width, and MIN(J, K) = N*L, where N and L are both integers;

[0023] For each asynchronous subnet measurement, the i-th measurement window within the large period P has a starting subframe number of The value of satisfies the following formula:

[0024]

[0025] Among them, mod means remainder; v=RANDBETWEEN(0,N-1), which means that any value between 0, 1, 2, ..., N-1 is selected, and the v value of the current node in each asynchronous subnet measurement period P remains consistent; i=1, 2, ..., N; sf_shift_NR_SSB represents the time slot offset of the measurement small window, 0≤sf_shift_NR_SSB<MIN(J, K).

[0026] Furthermore, the specific method of step 6 is:

[0027] The current node compares the subnet where the current node is located with the subnet clock information, subnet master node information and number of nodes in the detected asynchronous subnet, and defines the subnet with more nodes as the master subnet, and the subnet with fewer nodes as the slave subnet. If the number of nodes in the two subnets is the same, the subnet with the smaller master node number is defined as the master subnet, and the subnet with the larger master node number is defined as the slave subnet.

[0028] If the subnet where the current node is located is the master subnet, the subnet where the current node is located continues to execute step 2. If the subnet where the current node is located is a slave subnet, the master node information and clock information of the master subnet are broadcast within the subnet where the current node is located. After that, all nodes in the subnet where the current node is located exit the connection state and reconnect to the master subnet to merge into a new subnet, and continue to execute step 2 until all asynchronous subnets are merged.

[0029] Due to the adoption of the above technical solution, the beneficial effects of the present invention compared with the prior art are:

[0030] The present invention provides a method for asynchronous subnets to discover and merge each other during business continuity. By defining a dynamic synchronization signal measurement window, the success rate of asynchronous nodes being detected each other is effectively guaranteed. This method is of great significance for multi-node business intercommunication in special application scenarios without a unified clock source. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is an overall flow chart of a method for asynchronous subnet fusion in a 5G access and backhaul integrated system in an embodiment of the present invention.

[0032] Figure 2 Schematic diagram of a synchronization signal measurement interval MG in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0034] A method for asynchronous subnet fusion in a 5G access backhaul integrated system is applied to the fusion of asynchronous subnets without a unified satellite synchronization source, such as Figure 1 As shown, the following steps are included:

[0035] Step 1: Each node performs initial access and intra-subnet synchronization, thereby forming multiple independent subnets with different frame boundaries;

[0036] Step 2, each node sets its own synchronization signal measurement interval MG, and detects the synchronization signal of the asynchronous subnet within its own synchronization signal measurement interval MG; if the synchronization signal of the asynchronous subnet is detected, step 3 is executed, otherwise, step 2 is continued;

[0037] Specifically, this embodiment introduces the concept of a detection interval for a connected wireless ad hoc network node to detect a new asynchronous neighbor node:

[0038] In the time-division 5G access and backhaul integrated system, the NR access waveform and the ad hoc waveform use the same frequency band for data transmission, in which some time slots are fixedly allocated to NR services, and some time slots are fixedly allocated to ad hoc services. When multiple new nodes are connected to each other for the first time, one of the nodes is determined as the master node in the network, that is, the first node of the subnet, according to predefined rules, and the clock of other nodes is aligned to this node. When a new ad hoc node is just connected to the network, it is necessary to determine the frame boundary of this node by searching for the ad hoc synchronization signal in the currently synchronized ad hoc network. After the nodes in the subnet complete the initial synchronization process, the synchronization signal is periodically sent in the predefined ad hoc synchronization time slot. Through the periodic measurement of the synchronization signal and clock adjustment between the nodes, high-precision synchronization of the ad hoc network in the scenario without a unified clock source is achieved, and it is synchronized to the local clock of the current subnet first node.

[0039] The clock of the first node of the subnet is a local clock, and the deviation between the local clocks of the first nodes of different subnets is an arbitrary value, so the corresponding frame boundaries may be completely different. Receiving the synchronization signal of the neighboring node according to the synchronization time slot position of the current subnet node is only valid for nodes in the same subnet. Nodes between different subnets cannot detect each other's synchronization signals. When asynchronous subnets with different frame boundaries overlap in coverage during the movement process, it is necessary to support the functions of self-discovery and resynchronization. The self-discovery process of the time-asynchronous self-organizing network subnet needs to introduce a dynamically defined synchronization signal detection interval. In the detection interval, the self-organizing network node needs to suspend the transmission of NR services or self-organizing network services on the corresponding time slot and switch to the scanning mode of the synchronization signal. If only the synchronization signal of the neighboring node of the current subnet is received in the measurement interval, it is considered that no new subnet is currently discovered, and there is no need to trigger the fusion process of the asynchronous subnet. If the synchronization signal of other subnet nodes is received in the measurement interval, it is considered that the subnet overlap has occurred, and the fusion process of the asynchronous subnet needs to be triggered to form a unified new subnet with clock synchronization.

[0040] In a single subnet, each node periodically sends two types of synchronization signals, one is the NRSSB (NR access waveform synchronization signal) sent on the NR time slot, and the other is the ZZW SSB (self-organizing network waveform synchronization signal) sent on the ad hoc network time slot. In order to avoid the synchronization signal sending time slot of the adjacent subnet always falling outside the measurement interval of the current subnet node, the measurement interval for detecting asynchronous networks cannot be defined as a periodic static interval. The interval start time and interval width of the measurement interval for detecting asynchronous networks need to change dynamically according to a certain algorithm to ensure that the combination of multiple measurement intervals can detect the synchronization signal of the asynchronous subnet.

[0041] Each subnet has its own subnet head node, and all nodes in the same subnet are synchronized with the local clock source of the subnet head node. When the clock of the adjacent subnet is detected to be asynchronous with the current subnet clock in the MG, the node needs to receive the ZZW SSB of the adjacent subnet based on the clock information of the adjacent subnet. The ZZW SSB contains the clock information of the subnet, the subnet head node information, and the number of nodes in the subnet. Then, based on the information obtained from the ZZW SSB of the adjacent subnet, the node selects the larger subnet as the clock reference of the new subnet according to the size of the subnet. After detecting the neighboring node of the asynchronous subnet, the node of the smaller subnet needs to notify all nodes in the current subnet to modify the clock synchronization source. After all nodes in the smaller subnet receive the notification of modifying the clock synchronization source, a new network access process will be triggered and they will be connected to the larger subnet to form a unified subnet. If the two subnets are of the same size, the master node number of the new subnet will be determined according to the node number of the subnet head nodes in the two subnets.

[0042] Step 3: If the detected synchronization signal of the asynchronous subnet is an NR access waveform synchronization signal, execute step 4; if it is an ad hoc network waveform synchronization signal, execute step 5;

[0043] Step 4, obtaining the clock frame boundary of the asynchronous subnet, calculating the sending time slot position of the self-organizing network waveform synchronization signal of the asynchronous subnet, and detecting the self-organizing network waveform synchronization signal of the asynchronous subnet at the time slot position;

[0044] Step 5: According to the received self-organizing network waveform synchronization signal of the asynchronous subnet, the subnet clock information, subnet master node information and the number of nodes in the subnet of the asynchronous subnet are obtained;

[0045] Step 6, compare the subnet scale and master node number of the subnet where the current node is located with the asynchronous subnet, and determine the relationship between the master subnet and the slave subnet, where the master subnet continues to execute step 2, and the slave subnet merges into the master subnet, and then continues to execute step 2 until all asynchronous subnets are merged.

[0046] Furthermore, the specific method of step 1 is:

[0047] Each node performs synchronization signal detection for the entire period. If it detects the self-organizing network waveform synchronization signal of one or more neighboring nodes, and these self-organizing network waveform synchronization signals indicate that the number of nodes in the subnet is 1, the node with the smallest node number is selected as the master node, and then initiates the synchronization handshake process with the master node to synchronize the clock of this node with the clock of the master node;

[0048] If it is detected that the self-organizing network waveform synchronization signal of the neighboring node indicates that the number of nodes in the subnet is greater than 1, the synchronization process with the neighboring node is initiated to synchronize the clock of this node with the clock of the neighboring node, thereby forming a subnet with aligned frame boundaries. Nodes in different geographical areas are synchronously interconnected to form multiple independent subnets with different frame boundaries.

[0049] Furthermore, in step 2, each node sets its own synchronization signal measurement interval MG in the following specific manner:

[0050] For the current 5G access backhaul integrated system, the sending period of the NR access waveform synchronization signal is recorded as J milliseconds, and the sending period of the ad hoc network waveform synchronization signal is recorded as K milliseconds, then the total width of the synchronization signal measurement interval MG is set to S milliseconds, S = MIN (J, K) + synchronization signal sending time width; MIN () means taking the minimum value;

[0051] Set the asynchronous subnet measurement period P:

[0052] P = static_offset * N;

[0053] Wherein, N represents dividing the synchronization signal measurement interval MG within an asynchronous subnet measurement large cycle P into N measurement small windows, static_offset represents the sub-cycle occupied by each measurement small window, and the value of static_offset is an integer multiple of MIN(J, K);

[0054] The width of each small measurement window is L milliseconds + synchronization signal transmission time width, and MIN(J, K) = N*L, where N and L are both integers;

[0055] For each asynchronous subnet measurement, the i-th measurement window within the large period P has a starting subframe number of The value of satisfies the following formula:

[0056]

[0057] Among them, mod means remainder; v=RANDBETWEEN(0,N-1), which means that any value between 0, 1, 2, ..., N-1 is selected, and the v value of the current node in each asynchronous subnet measurement period P remains consistent; i=1, 2, ..., N; sf_shift_NR_SSB represents the time slot offset of the measurement small window, 0≤sf_shift_NR_SSB<MIN(J, K).

[0058] Specifically, Figure 2As shown, in this embodiment, the transmission period of the synchronization signal of the NR access waveform is 20ms; the transmission period of the synchronization signal of the ad hoc network waveform is 40ms; the transmission width of the synchronization signal is 1ms; therefore, the total width of the synchronization signal measurement interval MG is set to S milliseconds, S = 21ms;

[0059] Set static_offset to 80ms. There are 4 measurement windows in an asynchronous subnet measurement cycle P, then the asynchronous subnet measurement cycle P = 320ms, and the width of each measurement window is 6ms; for a node in subnet A, v = RANDBETWEEN(0, N-1) = 1 in the current cycle; for a node in subnet B, v = RANDBETWEEN(0, N-1) = 2 in the current cycle; and the clock of subnet A and the actual clock frame boundary of subnet B have a deviation of 58ms;

[0060] like Figure 2 As shown,

[0061] The MG has an opportunity every 80ms to detect a portion of the time slot interval in the SSB transmission cycle;

[0062] Multiple MG opportunities within a 320ms period cover all time slots within the SSB transmission period. If a neighboring subnet sends an SSB within this SSB period, it can be detected by this subnet.

[0063] If the adjacent subnet node does not send a synchronization signal in the corresponding SSB period due to its own MG, the next asynchronous subnet measures the dynamic change of the MG in the large period to ensure that it can be detected in other detection periods.

[0064] The purpose of randomizing the value of v is to prevent the MGs of adjacent nodes from always overlapping, that is, when the local node is measuring the synchronization signal, the neighboring node always stops sending the synchronization signal;

[0065] The purpose of setting sf_shift_NR_SSB is to reduce the impact of MG on the NR SSB transmission of this node.

[0066] Furthermore, the specific method of step 6 is:

[0067] The current node compares the subnet where the current node is located with the subnet clock information, subnet master node information and number of nodes in the detected asynchronous subnet, and defines the subnet with more nodes as the master subnet, and the subnet with fewer nodes as the slave subnet. If the number of nodes in the two subnets is the same, the subnet with the smaller master node number is defined as the master subnet, and the subnet with the larger master node number is defined as the slave subnet.

[0068] If the subnet where the current node is located is the master subnet, the subnet where the current node is located continues to execute step 2. If the subnet where the current node is located is a slave subnet, the master node information and clock information of the master subnet are broadcast within the subnet where the current node is located. After that, all nodes in the subnet where the current node is located exit the connection state and reconnect to the master subnet to merge into a new subnet, and continue to execute step 2 until all asynchronous subnets are merged.

[0069] In summary, the present invention provides a method for asynchronous subnets to discover and merge each other during the service continuity process. By defining a dynamic synchronization signal measurement window, the success rate of asynchronous nodes being detected by each other is effectively guaranteed. This is of great significance for multi-node service interoperability in special application scenarios without a unified clock source.

[0070] Those skilled in the art will appreciate that the embodiments described are intended to help readers understand the principles of the present invention, and should be understood that the scope of protection of the present invention is not limited to the embodiments described. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for asynchronous subnet fusion in a 5G access backhaul integrated system, applied to the fusion of asynchronous subnets without a unified satellite synchronization source, characterized in that: The following steps are involved: Step 1: Each node performs initial access and intra-subnet synchronization, thereby forming multiple independent subnets with different frame boundaries; Step 2, each node sets its own synchronization signal measurement interval MG, and detects the synchronization signal of the asynchronous subnet within its own synchronization signal measurement interval MG; if the synchronization signal of the asynchronous subnet is detected, step 3 is executed, otherwise, step 2 is continued; Step 3: If the detected synchronization signal of the asynchronous subnet is an NR access waveform synchronization signal, execute step 4; if it is an ad hoc network waveform synchronization signal, execute step 5; Step 4, obtaining the clock frame boundary of the asynchronous subnet, calculating the sending time slot position of the self-organizing network waveform synchronization signal of the asynchronous subnet, and detecting the self-organizing network waveform synchronization signal of the asynchronous subnet at the time slot position; Step 5: According to the received self-organizing network waveform synchronization signal of the asynchronous subnet, the subnet clock information, subnet master node information and the number of nodes in the subnet of the asynchronous subnet are obtained; Step 6, compare the subnet scale and master node number of the subnet where the current node is located with the asynchronous subnet, and determine the relationship between the master subnet and the slave subnet, where the master subnet continues to execute step 2, and the slave subnet merges into the master subnet, and then continues to execute step 2 until all asynchronous subnets are merged.

2. According to the method of claim 1, wherein: The specific method of step 1 is: Each node performs synchronization signal detection for the entire period. If it detects the self-organizing network waveform synchronization signal of one or more neighboring nodes, and these self-organizing network waveform synchronization signals indicate that the number of nodes in the subnet is 1, the node with the smallest node number is selected as the master node, and then initiates the synchronization handshake process with the master node to synchronize the clock of this node with the clock of the master node; If it is detected that the self-organizing network waveform synchronization signal of the neighboring node indicates that the number of nodes in the subnet is greater than 1, the synchronization process with the neighboring node is initiated to synchronize the clock of this node with the clock of the neighboring node, thereby forming a subnet with aligned frame boundaries. Nodes in different geographical areas are synchronously interconnected to form multiple independent subnets with different frame boundaries.

3. The method for asynchronous subnet fusion in a 5G access backhaul integrated system according to claim 2, characterized in that: In step 2, each node sets its own synchronization signal measurement interval MG in the following specific manner: For the current 5G access backhaul integrated system, the sending period of the NR access waveform synchronization signal is recorded as J milliseconds, and the sending period of the networking waveform synchronization signal is recorded as K milliseconds. Then the total width of the synchronization signal measurement interval MG is set to S milliseconds, S = MIN (J, K) + synchronization signal sending time width; Set the asynchronous subnet measurement period P: P = static_offset * N; Wherein, N represents dividing the synchronization signal measurement interval MG within an asynchronous subnet measurement large cycle P into N measurement small windows, static_offset represents the sub-cycle occupied by each measurement small window, and the value of static_offset is an integer multiple of MIN(J, K); The width of each small measurement window is L milliseconds + synchronization signal transmission time width, and MIN(J, K) = N*L, where N and L are both integers; For each asynchronous subnet measurement, the i-th measurement window within the large period P has a starting subframe number of The value of satisfies the following formula: Among them, mod means remainder; v=RANDBETWEEN(0,N-1), which means that any value between 0, 1, 2, ..., N-1 is selected, and the v value of the current node in each asynchronous subnet measurement period P remains consistent; i=1, 2, ..., N; sf_shift_NR_SSB represents the time slot offset of the measurement small window, 0≤sf_shift_NR_SSB<MIN(J,K).

4. The method for asynchronous subnet fusion in a 5G access backhaul integrated system according to claim 3, characterized in that: The specific method of step 6 is: The current node compares the subnet where the current node is located with the subnet clock information, subnet master node information and number of nodes in the detected asynchronous subnet, and defines the subnet with more nodes as the master subnet, and the subnet with fewer nodes as the slave subnet. If the number of nodes in the two subnets is the same, the subnet with the smaller master node number is defined as the master subnet, and the subnet with the larger master node number is defined as the slave subnet. If the subnet where the current node is located is the master subnet, the subnet where the current node is located continues to execute step 2. If the subnet where the current node is located is a slave subnet, the master node information and clock information of the master subnet are broadcast within the subnet where the current node is located. After that, all nodes in the subnet where the current node is located exit the connection state and reconnect to the master subnet to merge into a new subnet, and continue to execute step 2 until all asynchronous subnets are merged.

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