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CN111181663A - Fast initial access method and device on unlicensed spectrum - Google Patents

Fast initial access method and device on unlicensed spectrum Download PDF

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Publication number
CN111181663A
CN111181663A CN201811334258.XA CN201811334258A CN111181663A CN 111181663 A CN111181663 A CN 111181663A CN 201811334258 A CN201811334258 A CN 201811334258A CN 111181663 A CN111181663 A CN 111181663A
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signal block
transmission
time
synchronous signal
transmission window
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赵莹
池连刚
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Potevio Information Technology Co Ltd
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Potevio Information Technology Co Ltd
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B17/00Monitoring; Testing
    • H04B17/30Monitoring; Testing of propagation channels
    • H04B17/382Monitoring; Testing of propagation channels for resource allocation, admission control or handover
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B17/00Monitoring; Testing
    • H04B17/30Monitoring; Testing of propagation channels
    • H04B17/309Measuring or estimating channel quality parameters

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  • Computer Networks & Wireless Communication (AREA)
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  • Mobile Radio Communication Systems (AREA)

Abstract

The embodiment of the invention provides a quick initial access method and a quick initial access device on an unauthorized frequency spectrum. The method comprises the following steps: monitoring the channel state on the used unauthorized frequency spectrum, and determining a transmission window for sending a synchronous signal block according to the channel state, wherein the transmission window comprises N time slots, and the starting time of each time slot is a transmission time; two synchronization signal blocks are transmitted in parallel to the terminal via two directional beams at each transmission instant. The embodiment of the invention simultaneously uses two directional beams to send the synchronous signal blocks to the terminal in parallel at each sending moment of the transmission window, so that the transmission window can provide at least two sub-windows which can finish transmitting all the synchronous signal blocks, thereby increasing the sending moment, quickly realizing initial access by the base station with shorter time, lower collision probability and higher efficiency, and reducing the delay of the initial access of the terminal.

Description

Fast initial access method and device on unlicensed spectrum
Technical Field
The embodiment of the invention relates to the technical field of communication, in particular to a quick initial access method and a quick initial access device on an unlicensed spectrum.
Background
In order to meet the higher demand of the available frequency band of the future 5G communication network, based on the use of the conventional licensed spectrum, by means of technologies such as massive antennas, high frequency communication, beam forming and the like in the 5G network, the 3GPP organization has confirmed that an Unlicensed spectrum (NR-U), such as Bands below 7GHz, 7-52.6GHz and above 52.6GHz, will be used in the 5G network, so as to make up the scarcity of the licensed spectrum and improve the transmission efficiency and the coverage.
The use of NR-U communications with 5G networks is still under investigation. Compared with the 4G network, due to the introduction of New technologies and concepts such as a synchronization signal block, beam scanning, a partial bandwidth and the like in 5G, the initial access, random access and beam management of a 5G NR (5 Generation New RAT, 5G New radio access technology) channel are greatly changed. Further, the usage of the unlicensed spectrum also needs to meet the requirements on the maximum occupied channel bandwidth, the maximum occupied channel time, and the like, and especially needs to consider the influence of a Listen Before Talk (Listen Before Talk, LBT) mechanism on the initial access. The current research on initial access based on the NR-U frequency band is still in a starting stage, and no access method and conclusion specified by a protocol exist.
Disclosure of Invention
Aiming at the technical problems in the prior art, the embodiment of the invention provides a quick initial access method and a quick initial access device on an unlicensed spectrum.
In a first aspect, an embodiment of the present invention provides a method for fast initial access on an unlicensed spectrum, where the method is applied to a base station, and the method includes:
monitoring the channel state on the used unauthorized frequency spectrum, and determining a transmission window for sending a synchronous signal block according to the channel state, wherein the transmission window comprises N time slots, and the starting time of each time slot is a transmission time;
two synchronization signal blocks are transmitted in parallel to the terminal via two directional beams at each transmission instant.
In a second aspect, an embodiment of the present invention provides a method for fast initial access on an unlicensed spectrum, where the method is applied to a terminal, and the method includes:
receiving two synchronous signal blocks simultaneously sent by a base station at each transmission moment of a transmission window, wherein the transmission window comprises N time slots, and the starting moment of each time slot is a transmission moment;
acquiring the sequence number of a synchronous signal block according to system information carried by the synchronous signal block, and acquiring the sequence number of a sub-window where the synchronous signal block is located according to scrambling code information carried by the synchronous signal block;
and carrying out frame synchronization and time slot synchronization according to the sequence number of the synchronization signal block and the sequence number of the positioned sub-window.
In a third aspect, an embodiment of the present invention provides a fast initial access apparatus on an unlicensed spectrum, where the apparatus is located at a base station, and the apparatus includes:
a first determining module, configured to monitor a channel state on a used unlicensed spectrum, and determine a transmission window for sending a synchronization signal block according to the channel state, where the transmission window includes N time slots, and a start time of each time slot is a transmission time;
and the sending module is used for sending two synchronous signal blocks to the terminal in parallel through two directional beams at each transmission moment.
In a fourth aspect, an embodiment of the present invention provides a fast initial access apparatus on an unlicensed spectrum, where the apparatus is located at a terminal, and the apparatus includes:
a receiving module, configured to receive two synchronization signal blocks simultaneously sent by a base station at each transmission time of a transmission window, where the transmission window includes N time slots, and a start time of each time slot is a transmission time;
the acquisition module is used for acquiring the serial number of the synchronous signal block according to the system information carried by the synchronous signal block and acquiring the serial number of a sub-window where the synchronous signal block is located according to the scrambling code information carried by the synchronous signal block;
and the synchronization module is used for carrying out frame synchronization and time slot synchronization according to the sequence number of the synchronization signal block and the sequence number of the positioned sub-window.
In a fifth aspect, an embodiment of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the method provided in the first aspect or the second aspect.
In a sixth aspect, an embodiment of the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored, and the computer program, when executed by a processor, implements the method provided in the first aspect or the second aspect.
According to the method and the device for the quick initial access on the unlicensed spectrum, provided by the embodiment of the invention, the two directional beams are simultaneously used at each sending moment of the transmission window to send the synchronous signal blocks to the terminal in parallel, so that the transmission window can provide at least two sub-windows capable of transmitting all the synchronous signal blocks, the sending moment is increased, the base station can quickly realize the initial access in shorter time, lower collision probability and higher efficiency, and the delay of the initial access of the terminal is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a flowchart illustrating a fast initial access method on an unlicensed spectrum according to an embodiment of the present invention;
FIG. 2 is a diagram of a synchronization signal block according to an embodiment of the present invention;
fig. 3 is a schematic diagram of beam directions of an antenna array in polar coordinates according to an embodiment of the present invention;
FIG. 4 is a diagram illustrating a time-frequency structure of a synchronization signal block according to an embodiment of the present invention;
FIG. 5 is a diagram illustrating the transmission of a synchronization signal block in a transmission window according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of beam directions at two consecutive transmission time instances k and k +1 according to an embodiment of the present invention;
FIG. 7 is a diagram illustrating transmission of all synchronization signal blocks in two sub-windows provided in a 5ms transmission window according to an embodiment of the present invention;
fig. 8 is a flowchart illustrating a fast initial access method on unlicensed spectrum according to another embodiment of the present invention;
fig. 9 is a schematic structural diagram of a fast initial access apparatus on an unlicensed spectrum according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of a fast initial access apparatus on unlicensed spectrum according to another embodiment of the present invention;
fig. 11 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a quick initial access method on an unauthorized frequency spectrum, which is applied to a base station.
Fig. 1 shows a flowchart of a fast initial access method on an unlicensed spectrum according to an embodiment of the present invention.
For a 5G base station (gNB) end in a communication scene using an NR-U unlicensed frequency band, L beamforming matrixes are configured on the basis of a large-scale antenna (Massive MIMO) and a beamforming technology, and the L beamforming matrixes are respectively W beamforming matrixes1,…,WLAnd each beam forming matrix corresponds to one directional antenna beam, L directional antenna beams can be formed. According to the existing standard, L may take the value of 4, 8 or 64 for different frequency bands.
In the configuration process, the L directional antenna beams have the same beam shape but different directions, are uniformly distributed in the horizontal direction of the airspace of the base station gNB, and completely cover the range of a cell.
Each beam corresponds to a Block of Synchronization Signals (SSB), see fig. 2, where the horizontal axis in fig. 2 indicates time; let L synchronization signal blocks be SSB respectively1,…,SSBL(ii) a The L synchronization signal blocks correspond to the L beams one to one, and each synchronization signal block is transmitted through the beam corresponding to the synchronization signal block, and is used for a User Equipment (UE) or a terminal to acquire air interface information and establish a connection with the gNB.
Fig. 3 shows a schematic diagram of beam directions of the antenna array in polar coordinates, and fig. 3 shows two beams SS with a horizontal coverage angle of the gNB of 360 degrees as an example1、SS2Main lobe diagram of (1), two beams SS1、SS2Respectively formed by a forming matrix W1、W2And (4) generating.
Referring to fig. 4, fig. 4 shows a time-frequency composition diagram of the SSB, wherein the horizontal axis indicates the time domain (T) and the vertical axis indicates the frequency domain (F); SSB includes Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and broadcast channel Signal (PBCH); the SSBs are respectively composed of different Orthogonal Frequency Division Multiplexing (OFDM) symbols. SSBs 1, …, SSBLs correspond to L beams, respectively.
Referring to FIG. 5, on a transmit window (Burst set window), in the first slot1Inner, transmitting SSB1With the beam pointing sequentially changed, the gNB sequentially transmits all signal blocks over N time slots.
As shown in fig. 1, the method for fast initial access on an unlicensed spectrum according to the embodiment of the present invention is applied to a base station, and specifically includes the following steps:
step 101, monitoring a channel state on a used unlicensed spectrum, and determining a transmission window for transmitting a synchronization signal block according to the channel state, wherein the transmission window comprises N time slots, and the starting time of each time slot is a transmission time;
based on the LBT mechanism, monitoring is required before occupying the channel, and a monitoring duration and a maximum channel occupation duration are set (the SSB duration of each synchronization signal block is much shorter than the maximum channel occupation duration). Before transmitting the synchronous signal, the base station sets a channel monitoring timer, monitors and records the channel state on the used NR-U frequency band, and if the channel is occupied, the base station can occupy the channel by waiting for the channel to be converted into an idle state.
In the NR protocol, the transmission window (transmission window) duration of all the synchronization signal blocks is 5ms, and 1-4 ms is required for transmitting all the signal blocks according to different parameter sets and the number of the synchronization signal blocks. The start end of the transmission window is the start time of transmitting the synchronous signal block, each transmission window comprises N time slots, and the start time of each time slot is one transmission time to sequentially transmit the synchronous signal block.
Step 102, two synchronization signal blocks are transmitted to the terminal in parallel through two directional beams at each transmission moment.
For the L beams, the beams are equally divided into 2 semicircles in the horizontal direction, and each semicircle comprises L/2 adjacent beams. At the time of transmitting continuous L/2 synchronous signal blocks, the base station simultaneously uses 2 beam forming matrixes at each transmitting time through the large-scale antenna array, two beams are different by a semicircle on the horizontal plane, namely for the transmitting time with the sequence number of k, the matrix W is simultaneously usedk,Wk+L/2And forming the signal block. 2 synchronization signal blocks are transmitted simultaneously through 2 directional beams, and thus a complete cell can be swept through consecutive L/2 transmission instants.
Fig. 6 shows beam patterns of two consecutive transmission time instants k and k +1 according to an embodiment of the present invention, and referring to fig. 6, a base station simultaneously transmits two signal blocks using two parallel beams at each transmission time instant, and the beams used at the two transmission time instants are different by one semicircle in a horizontal plane.
The method for fast initial access on the unlicensed spectrum, provided by the embodiment of the invention, can enable the transmission window to provide at least two sub-windows capable of transmitting all the synchronous signal blocks by simultaneously using two directional beams to transmit the synchronous signal blocks to the terminal at each transmission moment of the transmission window, thereby increasing the transmission moment, enabling the base station to fast realize initial access in shorter time, lower collision probability and higher efficiency, and reducing the delay of the initial access of the terminal.
It should be noted that, in the embodiment of the present invention, for different frequency bands, an LAA-LTE channel access mechanism is respectively used as a reference line or a starting point in an NR-U frequency band channel access process, and an NR HARQ feedback mechanism is used as a reference line for an NR-U frequency band HARQ enhancement design.
The embodiment of the invention realizes the use of the NR-U frequency band, makes up the shortage of authorized spectrum, improves the transmission efficiency and the coverage range, and meets the higher requirement of a future 5G communication network on available frequency band.
On the basis of the above embodiments, the synchronization signal blocks correspond to directional beams one to one, and each synchronization signal block is transmitted by using the corresponding directional beam.
Specifically, L beams have the same beam shape but different directions, are uniformly distributed in the horizontal direction of the airspace of the base station and completely cover the range of the cell, and L synchronous signal blocks SSB1,…,SSBLEach synchronization signal block is transmitted using a beam corresponding to the L beams, one-to-one correspondence.
On the basis of the foregoing embodiments, step 101 specifically includes:
when the channel state is in an idle state, determining the starting time of a transmission window, and determining the starting time of each time slot of the transmission window, wherein the length of each time slot is the time length for sending a synchronization signal block.
Based on the LBT mechanism, the base station sets a channel monitoring timer before transmitting the synchronous signal, monitors and records the channel state on the used NR-U frequency band, and if the channel is occupied, the base station can be occupied only by waiting for the channel to be converted into an idle state.
When the channel state is idle, a transmission window is opened, and on one transmission window, the base station sequentially transmits a synchronization signal block on N time slots (slots), wherein the length of each time slot is the time length for transmitting one synchronization signal block, and the starting end of each time slot sequentially transmits the synchronization signal blocks for the transmission time until all the synchronization signal blocks are transmitted.
On the basis of the foregoing embodiments, step 102 specifically includes:
and at each transmission moment, on two half areas which equally divide the coverage area of the cell on the horizontal plane, simultaneously adopting the directional wave beams to transmit corresponding synchronous signal blocks to the terminal.
At the time of transmitting continuous L/2 synchronous signal blocks, the base station simultaneously uses 2 beam forming matrixes at each transmitting time through the large-scale antenna array, two beams are different by a semicircle on the horizontal plane, namely for the transmitting time with the sequence number of k, the matrix W is simultaneously usedk,Wk+L/2And forming the signal block.
Compared with a conventional single-beam scanning and transmitting mode, the time required by the two-beam scanning method for covering the cell is shortened to 1/2 of the original time, and the transmission time of all signal blocks with the original maximum time length of 4ms can be shortened to be within 2 ms. Thus, at least two sub-windows (burst setwindow) may be provided in a 5ms transmission window (burst set window), each of which may transmit the entire signal block.
Fig. 7 shows a schematic diagram of two sub-windows provided in a 5ms transmission window for transmitting all synchronization signal blocks according to an embodiment of the present invention.
As shown in fig. 7, each sub-window may transmit the entire signal block, i.e. the transmission time of the synchronization signal block is increased. In the duration range of the first sub-window, if the channel is occupied, the second sub-window can be used as a substitute, and on the premise of meeting the LBT requirement, the efficiency of transmitting the synchronous signal block can be effectively improved, and the delay of acquiring the synchronous signal block when the UE is initially accessed is reduced.
On the basis of the above embodiments, the method further includes:
after determining the transmission window, determining the number of sub-windows which can transmit the full partial synchronization signal block and are contained in the transmission window;
and generating scrambling codes according to the number of the sub-windows, and scrambling the information of the synchronous signal block so that the synchronous signal block carries the sequence number of the sub-window where the synchronous signal block is located.
When the two-beam parallel scanning access mode is used, in order to avoid ambiguity in identifying multiple groups of synchronization signals by the UE, it is required to determine whether the synchronization signal block is at a regular position or a sub-window transmission position. In order to not occupy the system information resource of the PBCH, the embodiment of the invention adopts a scrambling mode to attach the sequence number information of the sub-window on the PBCH signal.
Specifically, scrambling codes are generated based on the number of sub-windows provided by the transmission window, assuming that the number of sub-windows is M, using a set of ordered scrambling code groups { SC) containing M +1 scrambling codesiThe symbol (i is more than or equal to 0 and less than or equal to M) indicates the sequence number i of the sub-window where a certain synchronous signal block is located (0 represents that single beam scanning is used), and the ith scrambling code SC is correspondingly usediThe PBCH information of the corresponding signal block is scrambled. The construction of a particular scrambling code may employ known sequences, such as gold sequences and the like, which have good autocorrelation and no correlation properties.
The fast initial access method on the unlicensed spectrum provided by the embodiment of the present invention is described above from the base station side, and the fast initial access method on the unlicensed spectrum provided by the embodiment of the present invention is described below from the terminal side with reference to the accompanying drawings.
Fig. 8 is a flowchart illustrating a fast initial access method on an unlicensed spectrum according to another embodiment of the present invention, which is applied to a terminal, and as shown in fig. 8, the method specifically includes the following steps:
step 201, receiving two synchronization signal blocks simultaneously transmitted by a base station at each transmission time of a transmission window, where the transmission window includes N time slots, and the starting time of each time slot is a transmission time;
specifically, in the process of searching synchronization in a cell, a terminal (e.g., UE) first acquires and tracks a synchronization signal block by a method of matching correlation. The embodiment of the invention simultaneously receives two synchronous signal blocks sent by two directional beams at each transmission moment of a transmission window.
Step 202, acquiring a sequence number of a synchronization signal block according to system information carried by the synchronization signal block, and acquiring a sequence number of a sub-window where the synchronization signal block is located according to scrambling code information carried by the synchronization signal block;
specifically, the sequence number information of the synchronization signal block can be obtained according to the system information carried by the PBCH signal in the synchronization signal block, in addition, the sequence number information of the sub-window can be obtained through the scrambling code attached to the PBCH, and the relative position of the received signal block in the complete 5ms transmission window can be further judged according to the information, so as to finally realize the acquisition of the complete information of the synchronization signal block.
And step 203, performing frame synchronization and time slot synchronization according to the sequence number of the synchronization signal block and the sequence number of the positioned sub-window.
Specifically, the terminal performs time slot synchronization and frame synchronization according to the acquired synchronization information, thereby quickly realizing initial access and shortening the time required by the initial access of the UE.
It should be noted that, in the embodiment of the present invention, for different frequency bands, an LAA-LTE channel access mechanism is respectively used as a reference line or a starting point in an NR-U frequency band channel access process, and an NR HARQ feedback mechanism is used as a reference line for an NR-U frequency band HARQ enhancement design.
The embodiment of the invention realizes the use of the NR-U frequency band, makes up the shortage of authorized spectrum, improves the transmission efficiency and the coverage range, and meets the higher requirement of a future 5G communication network on available frequency band.
Fig. 9 shows a schematic structural diagram of a fast initial access apparatus on an unlicensed spectrum according to an embodiment of the present invention, where the apparatus is located at a base station, and as shown in fig. 9, the apparatus includes a first determining module 101 and a sending module 102, where:
the first determining module 101 is configured to monitor a channel state on a used unlicensed spectrum, and determine a transmission window for sending a synchronization signal block according to the channel state, where the transmission window includes N time slots, and a start time of each time slot is a transmission time;
based on the LBT mechanism, monitoring is required before occupying the channel, and a monitoring duration and a maximum channel occupation duration are set (the SSB duration of each synchronization signal block is much shorter than the maximum channel occupation duration). Before transmitting the synchronous signal, the base station sets a channel monitoring timer, monitors and records the channel state on the used NR-U frequency band, and if the channel is occupied, the base station can occupy the channel by waiting for the channel to be converted into an idle state.
In the NR protocol, the transmission window duration of all the synchronization signal blocks is 5ms, and 1-4 ms is required for transmitting all the signal blocks according to different parameter sets and the number of the synchronization signal blocks. The start end of the transmission window is the start time of transmitting the synchronous signal block, each transmission window comprises N time slots, and the start time of each time slot is one transmission time to sequentially transmit the synchronous signal block.
The sending module 102 is configured to send two synchronization signal blocks to the terminal in parallel through two directional beams at each transmission time.
For the L beams, the beams are equally divided into 2 semicircles in the horizontal direction, and each semicircle comprises L/2 adjacent beams. At the time of transmitting continuous L/2 synchronous signal blocks, the base station simultaneously uses 2 beam forming matrixes at each transmitting time through the large-scale antenna array, two beams are different by a semicircle on the horizontal plane, namely for the transmitting time with the sequence number of k, the matrix W is simultaneously usedk,Wk+L/2And forming the signal block. 2 synchronization signal blocks are transmitted simultaneously through 2 directional beams, and thus a complete cell can be swept through consecutive L/2 transmission instants.
Fig. 6 shows beam patterns of two consecutive transmission time instants k and k +1 according to an embodiment of the present invention, and referring to fig. 6, a base station simultaneously transmits two signal blocks using two parallel beams at each transmission time instant, and the beams used at the two transmission time instants are different by one semicircle in a horizontal plane.
The fast initial access device on the unlicensed spectrum provided by the embodiment of the invention can enable the transmission window to provide at least two sub-windows capable of transmitting all the synchronous signal blocks by simultaneously using two directional beams to transmit the synchronous signal blocks to the terminal at each transmission moment of the transmission window, thereby increasing the transmission moment, enabling the base station to fast realize initial access in shorter time, lower collision probability and higher efficiency, and reducing the delay of the initial access of the terminal.
It should be noted that, in the embodiment of the present invention, for different frequency bands, an LAA-LTE channel access mechanism is respectively used as a reference line or a starting point in an NR-U frequency band channel access process, and an NR HARQ feedback mechanism is used as a reference line for an NR-U frequency band HARQ enhancement design.
On the basis of the above embodiments, the synchronization signal blocks correspond to directional beams one to one, and each synchronization signal block is transmitted by using the corresponding directional beam.
Specifically, L beams have the same beam shape but different directions, are uniformly distributed in the horizontal direction of the airspace of the base station and completely cover the range of a cell, and L synchronous signal blocks SSB1,…,SSBLEach synchronization signal block is transmitted using a beam corresponding to the L beams, one-to-one correspondence.
Specifically, the first determining module 101 is configured to determine a starting time of a transmission window and a starting time of each time slot of the transmission window when the channel state is an idle state, where a length of each time slot is a time duration for transmitting one synchronization signal block.
Based on the LBT mechanism, the base station sets a channel monitoring timer before transmitting the synchronous signal, monitors and records the channel state on the used NR-U frequency band, and if the channel is occupied, the base station can be occupied only by waiting for the channel to be converted into an idle state.
And when the channel state is idle, starting a transmission window, and on one transmission window, the base station sequentially transmits the synchronous signal blocks on N time slots, wherein the length of each time slot is the time length for transmitting one synchronous signal block, and the starting end of each time slot sequentially transmits the synchronous signal blocks at the transmission time until all the synchronous signal blocks are transmitted.
Specifically, the sending module 102 is configured to, at each transmission time, equally divide two half areas of a cell coverage area on a horizontal plane, and simultaneously transmit a corresponding synchronization signal block to the terminal by using a directional beam.
At the time of transmitting continuous L/2 synchronous signal blocks, the base station simultaneously uses 2 beam forming matrixes at each transmitting time through the large-scale antenna array, two beams are different by a semicircle on the horizontal plane, namely for the transmitting time with the sequence number of k, the matrix W is simultaneously usedk,Wk+L/2And forming the signal block.
Compared with a conventional single-beam scanning and transmitting mode, the time required by the two-beam scanning method for covering the cell is shortened to 1/2 of the original time, and the transmission time of all signal blocks with the original maximum time length of 4ms can be shortened to be within 2 ms. Thus, at least two sub-windows (burst setwindow) may be provided in a 5ms transmission window (burst set window), each of which may transmit the entire signal block.
Specifically, the apparatus further comprises:
a second determining module, configured to determine, after determining the transmission window, the number of sub-windows that can transmit the full-segment synchronization signal block and are included in the transmission window;
and the scrambling module is used for generating scrambling codes according to the number of the sub-windows and scrambling the information of the synchronous signal block so as to enable the synchronous signal block to carry the serial number of the sub-window where the synchronous signal block is located.
When the two-beam parallel scanning access mode is used, in order to avoid ambiguity in identifying multiple groups of synchronization signals by the UE, it is required to determine whether the synchronization signal block is at a regular position or a sub-window transmission position. In order to not occupy the system information resource of the PBCH, the embodiment of the invention adopts a scrambling mode to attach the sequence number information of the sub-window on the PBCH signal.
Specifically, scrambling codes are generated based on the number of sub-windows provided by the transmission window, assuming that the number of sub-windows is M, using a set of ordered scrambling code groups { SC) containing M +1 scrambling codesiThe symbol (i is more than or equal to 0 and less than or equal to M) indicates the sequence number i of the sub-window where a certain synchronous signal block is located (0 represents that single beam scanning is used), and the ith scrambling code SC is correspondingly usediThe PBCH information of the corresponding signal block is scrambled. The construction of a particular scrambling code may employ known sequences, such as gold sequences and the like, which have good autocorrelation and no correlation properties.
Fig. 10 shows a schematic structural diagram of a fast initial access apparatus on an unlicensed spectrum according to an embodiment of the present invention, where the apparatus is located at a terminal, and as shown in fig. 10, the apparatus includes a receiving module 201, an obtaining module 202, and a synchronization module 203, where:
the receiving module 201 is configured to receive two synchronization signal blocks simultaneously sent by a base station at each transmission time of a transmission window, where the transmission window includes N time slots, and a start time of each time slot is a transmission time;
specifically, in the process of searching synchronization in a cell, a terminal (e.g., UE) first acquires and tracks a synchronization signal block by a method of matching correlation. The embodiment of the invention simultaneously receives two synchronous signal blocks sent by two directional beams at each transmission moment of a transmission window.
The acquiring module 202 is configured to acquire a sequence number of a synchronization signal block according to system information carried by the synchronization signal block, and acquire a sequence number of a sub-window where the synchronization signal block is located according to scrambling code information carried by the synchronization signal block;
specifically, the sequence number information of the synchronization signal block can be obtained according to the system information carried by the PBCH signal in the synchronization signal block, in addition, the sequence number information of the sub-window can be obtained through the scrambling code attached to the PBCH, and the relative position of the received signal block in the complete 5ms transmission window can be further judged according to the information, so as to finally realize the acquisition of the complete information of the synchronization signal block.
The synchronization module 203 is configured to perform frame synchronization and time slot synchronization according to the sequence number of the synchronization signal block and the sequence number of the sub-window where the synchronization signal block is located.
Specifically, the terminal performs time slot synchronization and frame synchronization according to the acquired synchronization information, thereby quickly realizing initial access and shortening the time required by the initial access of the UE.
Fig. 11 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
As shown in fig. 11, the electronic device provided by the embodiment of the present invention includes a memory 301, a processor 302, a bus 303, and a computer program stored in the memory 301 and executable on the processor 302. The memory 301 and the processor 302 complete communication with each other through the bus 303.
The processor 302 is used for calling the program instructions in the memory 301 to implement the method of fig. 1 when executing the program.
For example, the processor implements the following method when executing the program:
monitoring the channel state on the used unauthorized frequency spectrum, and determining a transmission window for sending a synchronous signal block according to the channel state, wherein the transmission window comprises N time slots, and the starting time of each time slot is a transmission time;
two synchronization signal blocks are transmitted in parallel to the terminal via two directional beams at each transmission instant.
The electronic device provided by the embodiment of the invention can enable the transmission window to provide at least two sub-windows capable of transmitting all the synchronous signal blocks by simultaneously using two directional beams to transmit the synchronous signal blocks to the terminal in parallel at each transmission moment of the transmission window, thereby increasing the transmission moment, enabling the base station to rapidly realize initial access in shorter time, lower collision probability and higher efficiency, and reducing the delay of the initial access of the terminal.
Embodiments of the present invention also provide a non-transitory computer readable storage medium, on which a computer program is stored, and the program, when executed by a processor, implements the steps of fig. 1.
For example, the processor implements the following method when executing the program:
monitoring the channel state on the used unauthorized frequency spectrum, and determining a transmission window for sending a synchronous signal block according to the channel state, wherein the transmission window comprises N time slots, and the starting time of each time slot is a transmission time;
two synchronization signal blocks are transmitted in parallel to the terminal via two directional beams at each transmission instant.
The non-transitory computer-readable storage medium provided by the embodiment of the present invention simultaneously uses two directional beams to concurrently transmit a synchronization signal block to a terminal at each transmission time of a transmission window, so that the transmission window can provide at least two sub-windows capable of completing transmission of all synchronization signal blocks, thereby increasing the transmission time, enabling a base station to rapidly implement initial access in a shorter time, with a lower collision probability and with a higher efficiency, and reducing the delay of initial access of the terminal.
An embodiment of the present invention discloses a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, which when executed by a computer, enable the computer to perform the methods provided by the above-mentioned method embodiments, for example, including:
monitoring the channel state on the used unauthorized frequency spectrum, and determining a transmission window for sending a synchronous signal block according to the channel state, wherein the transmission window comprises N time slots, and the starting time of each time slot is a transmission time;
two synchronization signal blocks are transmitted in parallel to the terminal via two directional beams at each transmission instant.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A fast initial access method on unlicensed spectrum, the method being applied to a base station, the method comprising:
monitoring the channel state on the used unauthorized frequency spectrum, and determining a transmission window for sending a synchronous signal block according to the channel state, wherein the transmission window comprises N time slots, and the starting time of each time slot is a transmission time;
two synchronization signal blocks are transmitted in parallel to the terminal via two directional beams at each transmission instant.
2. The method of claim 1, wherein the synchronization signal blocks are in one-to-one correspondence with directional beams, and wherein each synchronization signal block is transmitted using a corresponding directional beam.
3. The method of claim 1, wherein the listening for channel conditions on an unlicensed spectrum used, and wherein determining a transmission window for transmitting a synchronization signal block based on the channel conditions comprises:
when the channel state is in an idle state, determining the starting time of a transmission window, and determining the starting time of each time slot of the transmission window, wherein the length of each time slot is the time length for sending a synchronization signal block.
4. The method of claim 1, wherein the transmitting two synchronization signal blocks in parallel to the terminal through two directional beams at each transmission time comprises:
and at each transmission moment, on two half areas which equally divide the coverage area of the cell on the horizontal plane, simultaneously adopting the directional wave beams to transmit corresponding synchronous signal blocks to the terminal.
5. The method of claim 1, further comprising:
after determining the transmission window, determining the number of sub-windows which can transmit the full partial synchronization signal block and are contained in the transmission window;
and generating scrambling codes according to the number of the sub-windows, and scrambling the information of the synchronous signal block so that the synchronous signal block carries the sequence number of the sub-window where the synchronous signal block is located.
6. A fast initial access method on an unlicensed spectrum, the method being applied to a terminal, the method comprising:
receiving two synchronous signal blocks simultaneously sent by a base station at each transmission moment of a transmission window, wherein the transmission window comprises N time slots, and the starting moment of each time slot is a transmission moment;
acquiring the sequence number of a synchronous signal block according to system information carried by the synchronous signal block, and acquiring the sequence number of a sub-window where the synchronous signal block is located according to scrambling code information carried by the synchronous signal block;
and carrying out frame synchronization and time slot synchronization according to the sequence number of the synchronization signal block and the sequence number of the positioned sub-window.
7. A fast initial access apparatus on unlicensed spectrum, the apparatus being located at a base station, the apparatus comprising:
a first determining module, configured to monitor a channel state on a used unlicensed spectrum, and determine a transmission window for sending a synchronization signal block according to the channel state, where the transmission window includes N time slots, and a start time of each time slot is a transmission time;
and the sending module is used for sending two synchronous signal blocks to the terminal in parallel through two directional beams at each transmission moment.
8. A fast initial access apparatus on unlicensed spectrum, the apparatus being located at a terminal, the apparatus comprising:
a receiving module, configured to receive two synchronization signal blocks simultaneously sent by a base station at each transmission time of a transmission window, where the transmission window includes N time slots, and a start time of each time slot is a transmission time;
the acquisition module is used for acquiring the serial number of the synchronous signal block according to the system information carried by the synchronous signal block and acquiring the serial number of a sub-window where the synchronous signal block is located according to the scrambling code information carried by the synchronous signal block;
and the synchronization module is used for carrying out frame synchronization and time slot synchronization according to the sequence number of the synchronization signal block and the sequence number of the positioned sub-window.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor when executing the program performs the steps of the method for fast initial access on unlicensed spectrum according to any of claims 1 to 6.
10. A non-transitory computer readable storage medium, having stored thereon a computer program, which, when being executed by a processor, performs the steps of the method for fast initial access on unlicensed spectrum according to any one of claims 1 to 6.
CN201811334258.XA 2018-11-09 2018-11-09 Fast initial access method and device on unlicensed spectrum Withdrawn CN111181663A (en)

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