A method for transmitting an SSB signal in a 5G mobile base station networking

Abstract

The application discloses a SSB signal sending method of 5G mobile base station networking, and belongs to the technical field of 5G base stations, and comprises the following steps: S1, determining an SSB burst set pattern according to a subcarrier spacing and a frequency band used by a mobile base station; S2, determining a period of the SSB burst set; S3, determining N according to an SSB time domain sending position quantity Lmax in the SSB burst set pattern, and grouping N mobile base stations into one group; S4, configuring the same SSB frequency domain position for the mobile base stations in the step S3; and S5, allocating continuous N PCIs to cells on the mobile base stations in the step S3. The application can accommodate more mobile base stations in dynamic networking in the same region, improves networking flexibility, disperses SSBs of multiple mobile base stations on orthogonal resources through grouping and sending, avoids mutual interference of SSB signals between base station groups, and does not affect UE neighborhood measurement and handover performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of 5G base stations, and in particular relates to an SSB signal sending method for networking of 5G mobile base stations. BACKGROUND

[0002] With the maturity of 5G technology, vehicle-mounted and airborne 5G base stations are widely used in temporary establishment of mobile 5G private networks. However, due to the limited coverage range of a single base station, multiple mobile base stations are often used for networking to achieve large-area coverage.

[0003] Due to the limited wireless spectrum resources, 5G base station networking generally adopts same-frequency networking. In order to avoid mutual interference between adjacent base stations / cells, the physical channel parameters of the cells need to be uniformly planned and configured. Each 5G-NR cell corresponds to a physical cell ID (PCI) for distinguishing the cells on the wireless side. The PCI planning of 5G-NR is very similar to the PCI planning of LTE and the scrambling code planning of 3g. Incorrect planning may affect the synchronization process, demodulation and handover signaling, and reduce network performance. When multiple mobile base stations are dynamically networked, the cell PCIs on adjacent base stations may interfere with each other due to Mod3 and Mod4 conflicts, causing performance degradation. SUMMARY

[0004] To solve the above problems and technical defects, the embodiments of the application adopt the following technical solutions. An SSB signal sending method for networking of 5G mobile base stations comprises the following steps.

[0005] Step S1: determining an SSB burst set pattern according to the subcarrier spacing and frequency band used by the mobile base station;

[0006] Step S2: determining the period of the SSB burst set;

[0007] Step S3: determining N=2*3*Lmax according to the number Lmax of SSB time domain sending positions in the SSB burst set pattern, and grouping N mobile base stations into one group;

[0008] Step S4: configuring the same SSB frequency domain position for the mobile base stations in step S3;

[0009] Step S5: configuring one 5G cell on each mobile base station, and allocating N consecutive PCIs to the cells on the mobile base stations in step S3;

[0010] Step S6: configuring the SSB burst set of the first N / 2 mobile base stations to be sent in the first half frame, and configuring the SSB burst set of the last N / 2 mobile base stations to be sent in the second half frame.

[0011] Step S7, the motorized base station is configured with its assigned PCI value, starting from the smallest PCI value, every 3 consecutive PCI base station cells in the same SSB transmission location in the SSB burst set, the other positions of the 3 base station cells on the SSB burst set pattern do not transmit SSB and data, and the transmission position is broadcast through the ssb-PositionsInBurst field of the SIB1 message.

[0012] Preferably, the PSS and SSS are encapsulated in an SSB signal block, and the SSB signal block further includes a PBCH;

[0013] The PSS is a primary synchronization signal, which helps the user equipment to determine the frame structure of the cell;

[0014] The SSS is a secondary synchronization signal, which is used to further refine the synchronization process and determine the cell identity;

[0015] The PBCH is a physical broadcast channel, which is used to transmit important system information.

[0016] Further, the PSS and SSS signal joint representation formula is:

[0017] ;

[0018] That is, PCI, Obtained from PSS, Obtained from SSS.

[0019] Preferably, the SSB is a signal used for time synchronization and frequency synchronization in 5G NR, which is used to help user equipment to perform initial access and cell search in 5G network; the SSB includes:

[0020] Synchronization function: SSB provides time synchronization and frequency synchronization information, so that the UE can be synchronized with the base station;

[0021] Cell search: UE uses SSB for cell search to determine the cell in the network and select the appropriate cell for access;

[0022] Resource positioning: SSB carries information for resource positioning, which helps UE to determine the distribution of physical resources;

[0023] Reference signal: SSB contains reference signal, which is used for UE to perform channel estimation and signal quality measurement;

[0024] Frame structure: SSB is part of the 5G NR frame structure, which is transmitted periodically in time;

[0025] Multiple access: SSBs are the basis for multiple access techniques in 5G NR, including beamforming based on OFDM.

[0026] Further, the period of the SSB burst set in the step S2 includes 10ms, 20ms, 40ms, 80ms and 160ms.

[0027] Preferably, the SSB burst set pattern is the distribution of each SSB in time domain in one SSB burst set. In the NR system, five SSB burst set patterns are supported in one SSB burst set, and the pattern defines the exact position of the SSB in time domain. The specific design principles are as follows:

[0028] Subcarrier spacing 15 kHz;

[0029] The index of the first symbol where the SSB is located is {2, 8} + 14n; n = 0 and 1 when the carrier frequency f <= 3GHz; n = 0, 1, 2 and 3 when the carrier frequency 3GHz < f <= 6GHz.

[0030] Subcarrier spacing 30 kHz;

[0031] The index of the first symbol where the SSB is located is {4, 8, 16, 20} + 28n; n = 0 when the carrier frequency f <= 3GHz; n = 0 and 1 when the carrier frequency 3GHz < f <= 6GHz.

[0032] Subcarrier spacing 30 kHz;

[0033] The index of the first symbol where the SSB is located is {2, 8} + 14n; n = 0 and 1 when the carrier frequency f <= 3GHz; n = 0, 1, 2 and 3 when the carrier frequency 3GHz < f <= 6GHz.

[0034] Subcarrier spacing 120 kHz;

[0035] The index of the first symbol where the SSB is located is {4, 8, 16, 20} + 28n; n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17 and 18 when the carrier frequency f > 6GHz.

[0036] Subcarrier spacing 240 kHz;

[0037] The index of the first symbol where the SSB is located is {8, 12, 16, 20, 32, 36, 40, 44} + 56*n; n = 0, 1, 2, 3, 5, 6, 7 and 8 when the carrier frequency f > 6GHz.

[0038] Preferably, the SS / PBCH block in the step S1 has a unique number, and the low-frequency number information is directly obtained from the pilot of the PBCH channel; and the high-frequency number information is obtained from the PBCH pilot signal or the MIB information.

[0039] Compared with the prior art, the beneficial effects of the embodiments of the application are:

[0040] (1) The application can accommodate more mobile base stations in the same region dynamic networking, improving the networking flexibility; by grouping, the SSBs of multiple mobile base stations are dispersed to send on orthogonal resources, avoiding the mutual interference of SSB signals between base station groups; all the cells of the mobile base stations are still the same frequency neighbor relationship, without affecting the neighbor measurement and handover performance of the UE. BRIEF DESCRIPTION OF DRAWINGS

[0041] In the drawings:

[0042] Figure 1 The system flowchart of the embodiments of the application. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme of the embodiments of the application will be described clearly and completely below with reference to the drawings of the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, not all the embodiments of the application. The components of the embodiments of the application described and shown in the drawings herein can be arranged and designed in various different configurations. EMBODIMENT

[0044] As shown in the drawings, a SSB signal sending method for 5G mobile base station networking includes: Figure 1

[0045] Step S1, determining the SSB burst set pattern according to the subcarrier spacing and frequency band used by the mobile base station;

[0046] Step S2, determining the period (greater than or equal to 10ms) of the SSB burst set;

[0047] Step S3, determining N=2*3*Lmax according to the number Lmax of SSB time domain sending positions in the SSB burst set pattern, and grouping N mobile base stations into a group;

[0048] Step S4, configuring the same SSB frequency domain position for the mobile base stations in step S3;

[0049] Step S5, configuring one 5G cell on each mobile base station, and allocating continuous N PCIs to the cells on the mobile base stations in step S3;

[0050] ​Step S6, the SSB burst set of the first N / 2 mobile base stations is configured to be sent in the first half frame, and the SSB burst set of the last N / 2 mobile base stations is configured to be sent in the second half frame.

[0051] Step S7, the mobile base stations are arranged in the SSB burst set according to the PCI values allocated to them, starting from the smallest PCI value, and every 3 consecutive PCI base station cells are arranged in the same SSB sending position in the SSB burst set, and the other positions of the 3 base station cells in the SSB burst set pattern do not send SSB or data, and the sending position is broadcast through the ssb-PositionsInBurst field of the SIB1 message.

[0052] The PCI (Physical Cell Identity) of the 5G NR cell is part of the Cell ID, used to identify a cell within a tracking area (Tracking Area), and the PCI has a total of 1008 values. In NR, the PCI is grouped into three groups, each with 336 values. The PSS and SSS signals of the cell jointly represent:

[0053] ;

[0054] Wherein That is, the PCI, obtained from the PSS, obtained from the SSS, the PSS is the primary synchronization signal, and the SSS is the secondary synchronization signal; these two signals are key signals for cell search and synchronization in 5G NR networks, PSS is used to help user equipment determine the frame structure of the cell, and SSS is used to further refine the synchronization process and determine the cell identity; the two signals work together to ensure that user equipment can accurately synchronize with 5G base stations and identify cells; in 5G NR, PSS and SSS are usually encapsulated in a signal block called SSB, which also includes PBCH for transmitting important system information.

[0055] SSB is a signal used for time and frequency synchronization in 5G NR, used to help user equipment (UE) perform initial access and cell search in 5G networks, and SSB has the following characteristics:

[0056] Synchronization function: SSB provides time synchronization and frequency synchronization information, allowing UE to synchronize with the base station (gNodeB).

[0057] Cell search: UE uses SSB for cell search to determine the cells in the network and select the appropriate cell for access.

[0058] Resource positioning: SSB carries information for resource positioning, helping UE determine the distribution of physical resources.

[0059] Reference signal: SSB contains reference signals, which are used by UEs for channel estimation and signal quality measurement.

[0060] Frame structure: SSB is part of the 5G NR frame structure, which is transmitted periodically in time.

[0061] Multiple access: SSB is the basis for multiple access technologies in 5G NR, including OFDM-based beamforming technology.

[0062] The design of SSB meets the needs of 5G NR for high efficiency, high precision synchronization and cell search, and the value planning of SSB under the networking condition affects the network performance. Generally, the PCI value should be unique: the PCI value in different cells within the same station should be unique to avoid confusion.

[0063] PSS sequence index value cannot be repeated: the PSS sequence index value in different cells within the same station cannot be repeated.

[0064] The PSS sequence value of adjacent cells should be different to avoid confusion.

[0065] The PCI of adjacent cells avoids mod3, mod4 and mod30 conflicts.

[0066] For mobile base stations, generally use omnidirectional antennas, each base station has an omnidirectional cell. Due to limited spectrum, in order to meet the capacity demand, mobile base stations need to be networked on the same frequency. When multiple mobile base stations are dynamically networked on the same frequency, the present application utilizes the mechanism of SSB supporting multiple beams in 5G NR to accommodate up to 24 mobile base stations on the same frequency in the same region, allowing these mobile base stations to be neighbors, greatly increasing the flexibility of networking.

[0067] In order to support beam scanning, the PBCH channel and PSS / SSS are combined in NR, occupying 4 consecutive symbols in time domain and 20 RBs in frequency domain, forming an SS / PBCH block (SSB); PSS and SSS occupy symbols 0 and 2 in SSB, respectively; PBCH channel occupies symbols 1 and 3, and also occupies part of the RE in symbol 2; multiple SSBs can be transmitted in each half frame (5ms) to form an SSB burst set (bust); the number of SSBs contained in an SSB burst set is at most Lmax, which is also the maximum number of SSBs in a half frame (5ms); SSB burst set is transmitted periodically, and the period of SSB burst set has multiple options, such as 10ms, 20ms, 40ms, 80ms, 160ms, etc., which is determined by network configuration;

[0068] The default period for UE network search is 20ms.

[0069] SSBs within a SSB burst set are used for beam sweeping to cover the service range of the entire cell. At high frequency bands, multiple SSBs within a SSB burst set can be used for beam sweeping to enhance cell coverage. At low frequency bands, a UE can also perform signal combining by receiving multiple SSBs in a SSB burst set to improve the demodulation capability of SSBs.

[0070] NR only supports TDM manner for SSB beam sweeping, and does not support FDM manner.

[0071] The transmission time of a SSB burst set is within 5 ms (i.e., half radio frame). The SSB burst set pattern refers to the distribution of each SSB in the time domain in a SSB burst set. In the NR system, the 3GPP standard specifies that a SSB burst set supports five SSB burst set patterns, which define the exact position of SSBs in the time domain. The specific design principles are as follows.

[0072] Case A: subcarrier spacing 15 kHz.

[0073] The index of the first symbol where the SSB is located is {2, 8} + 14n.

[0074] When the carrier frequency f <= 3 GHz, n = 0 and 1; when the carrier frequency 3 GHz < f <= 6 GHz, n = 0, 1, 2 and 3.

[0075] Case B: subcarrier spacing 30 kHz.

[0076] The index of the first symbol where the SSB is located is {4, 8, 16, 20} + 28n.

[0077] When the carrier frequency f <= 3 GHz, n = 0; when the carrier frequency 3 GHz < f <= 6 GHz, n = 0 and 1.

[0078] Case C: subcarrier spacing 30 kHz.

[0079] The index of the first symbol where the SSB is located is {2, 8} + 14n.

[0080] When the carrier frequency f <= 3 GHz, n = 0 and 1; when the carrier frequency 3 GHz < f <= 6 GHz, n = 0, 1, 2 and 3.

[0081] Case D: subcarrier spacing 120 kHz.

[0082] The index of the first symbol where the SSB is located is {4, 8, 16, 20} + 28n.

[0083] For carrier frequency f > 6GHz, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17 and 18.

[0084] Case E: subcarrier spacing 240 kHz.

[0085] The index of the first symbol where the SSB is located is {8, 12, 16, 20, 32, 36, 40, 44} + 56*n.

[0086] For carrier frequency f > 6GHz, n = 0, 1, 2, 3, 5, 6, 7 and 8.

[0087] For Sub3G low frequency used by mobile base station, there are 2 SSB transmission positions in each time slot, and there are Lmax=4 SSB transmission positions in each burst set period under low frequency (Sub3G); there are Lmax=8 SSB transmission positions under high frequency (Sub3G-Sub6G).

[0088] The SSB transmitted in each SSB transmission position has a unique number (SSB Index), and for low frequency, the number information is directly obtained from the pilot of the PBCH channel; for high frequency, the low 3 bits are obtained from the PBCH pilot signal, and the high 3 bits are obtained from the MIB information.

[0089] When the actual number of beams transmitted in the cell is less than the maximum SSB block defined in the protocol, the 3GPP protocol stipulates that the base station can indicate which SSB is not transmitted through the ssb-PositionsInBurst field of SIB1 or RRC signaling, and these idle positions can transmit PDSCH data.

[0090] The SSB burst set is defined on a half frame, and is repeatedly transmitted at a certain period, and the half frame can be the first half frame or the second half frame of a radio frame (10ms), and the UE identifies whether the current SSB is in the first half frame or the second half frame through the half frame indication bit in the PBCH or the DM-RS sequence of the PBCH.

[0091] The application encodes N (N = 6*Lmax) mobile base stations in the same region as a group, and the group of mobile base stations configures the same SSB frequency domain position, and allocates N consecutive PCIs to N cells on the group of base stations, and it is known from the description of the SSB burst pattern that for low frequency, there are 4 SSB transmission positions in each SSB burst set period, and N = 24.

[0092] The SSB burst set of the first 12 mobile base stations is configured to be transmitted in the first half frame, and the SSB burst set of the last 12 mobile base stations is configured to be transmitted in the second half frame.

[0093] The application configures the base station cells of every 3 consecutive PCIs in the same SSB sending position from the minimum PCI value according to the PCI values of the group of base stations, the 3 base station cells do not send SSB and data in other positions of the SSB burst set pattern (can be simply realized by sending SSB with 0 power), and broadcasts the sending position through the ssb-PositionsInBurst field of the SIB1 message.

[0094] In the application, the cells on the base stations are all same frequency neighboring areas, the method can also be used in the combined use scene of machine and fixed, generally, the fixed base station sends the SSB burst set pattern in the first half frame, and the mobile base station can send the SSB burst set pattern in the second half frame.

[0095] The application has the following advantages:

[0096] More mobile base stations can be accommodated in the dynamic networking in the same region, and the networking flexibility is improved;

[0097] The SSBs of multiple mobile base stations are dispersed to send on the orthogonal resources through grouping, and the mutual interference of SSB signals between the base station groups is avoided;

[0098] The cells of all mobile base stations are still same frequency neighboring areas, and the neighboring area measurement and switching performance of the UE are not affected.

[0099] It should be noted that the application can be applied to the dynamic networking of mobile base stations, and the mixed networking of mobile base stations and fixed networks.

[0100] The above-mentioned embodiments only express the preferred embodiments of the application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the application, a number of variations, improvements and substitutions can be made, which belong to the protection scope of the application.

Claims

1. A method for transmitting SSB signals in a 5G mobile base station networking, the method comprising: transmitting SSB signals in a first frequency band; and transmitting SSB signals in a second frequency band different from the first frequency band. Comprise: Step S1, determine the SSB burst set pattern according to the subcarrier spacing and frequency band used by the mobile base station; Step S2, determine the period of SSB burst set; Step S3, determine N=2*3*Lmax according to the number of SSB time domain sending positions Lmax in SSB burst set pattern, and group N mobile base stations; Step S4, configure the same SSB frequency domain position for the mobile base stations in step S3; Step S5, configure one 5G cell on each mobile base station, and allocate continuous N PCIs to the cells on the mobile base stations in step S3; Step S6, configure the SSB burst set of the first N / 2 mobile base stations to be sent in the first half frame, and configure the SSB burst set of the last N / 2 mobile base stations to be sent in the last half frame; Step S7, according to the PCI value allocated to the mobile base station, starting from the minimum PCI value, configure the base station cells of every 3 consecutive PCIs in the same SSB sending position in the SSB burst set, and the other positions of the 3 base station cells in the SSB burst set pattern do not send SSB or data, and broadcast their sending positions through the ssb-PositionsInBurst field of SIB1 message. 2.The SSB signal transmission method of a 5G mobile base station group network according to claim 1, wherein, PSS and SSS are encapsulated in SSB signal block, which also includes PBCH; The PSS is the primary synchronization signal, which helps user equipment to determine the frame structure of the cell; The SSS is the secondary synchronization signal, which is used to further refine the synchronization process and determine the cell identity; The PBCH is the physical broadcast channel, which is used to transmit important system information. 3.The SSB signal transmission method of claim 2, wherein, The joint representation formula of PSS and SSS signals is: ； i.e. PCI, from the PSS, from the SSS.

4. The SSB signal transmission method of claim 2, wherein, The SSB is a signal used for time synchronization and frequency synchronization in 5G NR, which helps user equipment to perform initial access and cell search in 5G network; The SSB includes: Synchronization function: SSB provides time synchronization and frequency synchronization information, so that UE can synchronize with the base station; Cell search: UE uses SSB for cell search to determine the cell in the network and select the appropriate cell for access; Resource positioning: SSB carries information for resource positioning, helping UE to determine the distribution of physical resources; Reference signal: SSB contains reference signal, which is used for UE to perform channel estimation and signal quality measurement; Frame structure: SSB is part of the 5G NR frame structure, which is transmitted periodically in time; Multiple access: SSB is the basis of multiple access technologies in 5G NR, including OFDM-based beamforming technology.

5. The SSB signal transmission method of claim 1, wherein, The period of SSB burst set in step S2 includes 10ms, 20ms, 40ms, 80ms and 160ms.

6. The SSB signal transmission method of claim 5, wherein, SSB burst set pattern is the distribution of each SSB in time domain in one SSB burst set. In NR system, one SSB burst set supports five SSB burst set patterns, which define the exact position of SSB in time domain, and the specific design principles are as follows: Subcarrier spacing 15kHz; The index of the first symbol where the SSB is located is {2, 8} + 14n; n = 0 and 1 when the carrier frequency f <= 3GHz; n = 0, 1, 2 and 3 when the carrier frequency 3GHz < f <= 6GHz; The subcarrier spacing is 30kHz; The index of the first symbol where the SSB is located is {4, 8, 16, 20} + 28n; n = 0 when the carrier frequency f <= 3GHz; n = 0 and 1 when the carrier frequency 3GHz < f <= 6GHz; The subcarrier spacing is 30kHz; The index of the first symbol where the SSB is located is {2, 8} + 14n; n = 0 and 1 when the carrier frequency f <= 3GHz; n = 0, 1, 2 and 3 when the carrier frequency 3GHz < f <= 6GHz; The subcarrier spacing is 120kHz; The index of the first symbol where the SSB is located is {4, 8, 16, 20} + 28n; n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17 and 18 when the carrier frequency f > 6GHz; The subcarrier spacing is 240kHz; The index of the first symbol where the SSB is located is {8, 12, 16, 20, 32, 36, 40, 44} + 56*n; n = 0, 1, 2, 3, 5, 6, 7 and 8 when the carrier frequency f > 6GHz.

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