WO2016065642A1

WO2016065642A1 - Synchronization device and method

Info

Publication number: WO2016065642A1
Application number: PCT/CN2014/090118
Authority: WO
Inventors: 储育红; 胡军
Original assignee: 华为技术有限公司
Priority date: 2014-10-31
Filing date: 2014-10-31
Publication date: 2016-05-06
Also published as: WO2016065642A8; CN105960820B; CN105960820A

Abstract

The present invention relates to the field of wireless communication network technology, and disclosed are a synchronization device and method for solving the problem of high cost of absolute time synchronization between base stations. The method of the present invention comprises: when the base station to be synchronized is in sync with a frame number of a reference base station and in sync with a frame timing, an acquisition module acquires a first frame number and a first frame timing; the acquisition module acquires time information provided by a timing device of the base station to be synchronized so as to acquire a second frame number and a second frame timing by converting the time information; a computation module acquires the deviation between the first frame number and the second frame number and the deviation between the first frame timing and the second frame timing, and a synchronization module achieves absolute time synchronization with the reference base station based on the frame number deviation and the frame timing deviation, the reference base station being used to achieve the absolute time synchronization with the base station to be synchronized. The solution provided in the embodiment of the present invention is suitable for synchronization between base stations.

Description

Synchronization device and method

Technical field

The present invention relates to the field of wireless communication technologies, and in particular, to a synchronization apparatus and method.

Background technique

With the continuous development of wireless communication technology, time synchronization technology has become an important part of wireless communication technology. In LTE (Long Term Evolution), LTE includes two types of duplex modes: TDD (Time Division Duplex) and FDD (Frequency Division Duplex). In TDD, strict air interface frame numbers and frame timing synchronization are required between base stations to avoid interference between base stations.

At present, strict synchronization between base stations is achieved by adopting the GNSS (Global Navigation Satellite System) timing scheme or the 1588V2 (1588 Version 2, 1588 second edition) timing scheme. The base station adopts GNSS timing or adopts 1588V2 timing to receive the GPS signal from the satellite, and then extracts the clock synchronization signal from the GPS signal, and synchronizes between the base stations through the clock synchronization signal. However, the use cost and post-maintenance cost of GNSS timing and 1588V2 timing are higher, resulting in higher cost of achieving absolute time synchronization between base stations.

Summary of the invention

Embodiments of the present invention provide a synchronization apparatus and method for solving the problem of high cost of implementing absolute time synchronization between base stations.

In a first aspect, an embodiment of the present invention provides a synchronization apparatus, where the apparatus is applied to a base station to be synchronized, and the base station to be synchronized is a base station that synchronizes with a frame number of a reference base station and a frame timing, and the reference base station is a The base station to be synchronized provides a base station with a reference time, a reference frame number, and a reference frame timing, and the apparatus includes:

Obtaining a module, configured to obtain a first frame number and a first frame timing, and provide the first frame number and the first frame timing to a computing module, where the first frame number is the to-be-synchronized base station and the Reference frame a frame number after the synchronization, the first frame timing is a frame timing after the base station to be synchronized is synchronized with the reference frame timing;

An obtaining module, configured to acquire time information by using a first timing device, and provide the time information to the obtaining module, where the first timing device is configured to provide time information to the device;

The obtaining module is further configured to obtain a second frame number and a second frame timing according to the time information, and provide the second frame number and the second frame timing to the computing module;

The calculating module is configured to obtain a frame number deviation by using the first frame number and the second frame number; and obtain a frame timing deviation by using the first frame timing and the second frame timing, and The frame number deviation and the frame timing deviation are provided to the synchronization module;

The synchronization module is configured to complete a reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation.

In a first possible embodiment, in combination with the first aspect, when the time information includes a Coordinated Universal Time UTC time, the obtaining module includes:

An obtaining unit, configured to acquire a UTC time provided by the timing device, and provide the UTC time to the conversion unit;

The converting unit is configured to convert the UTC time into a global positioning system GPS time in combination with the leap second information; convert the GPS time into the second frame number and the second frame timing.

In a second possible embodiment, in combination with the first aspect or the first possible embodiment of the first aspect, the synchronization module includes:

a converting unit, configured to convert the frame number deviation and a frame timing deviation into a time difference value, and provide the time difference value to a calibration unit;

The calibration unit is configured to calibrate the time information by using the time difference to complete absolute time synchronization with the reference base station.

In a third possible embodiment, in combination with the second possible embodiment of the first aspect, The device also includes:

The first receiving module is configured to receive the alarm information sent by the reference base station, where the alarm information is used to indicate that the time difference is greater than or equal to a predetermined time difference.

In a fourth possible embodiment, in combination with the first aspect or any one of the above possible embodiments in the first aspect,

The synchronization module is further configured to synchronize the device to the first reference source to complete frequency synchronization with the reference base station, where the first reference source is the same as the reference source synchronized with the reference base station.

In a fifth possible embodiment, in combination with the first aspect or any of the first to third possible embodiments of the first aspect,

The synchronization module is further configured to synchronize the device to a second reference source to determine a frequency offset between the device and the reference base station, where the second reference source is different from a reference source synchronized with the reference base station When the frequency deviation is less than the predetermined frequency deviation, synchronization with the second reference source continues.

In a sixth possible embodiment, in combination with the first aspect or any one of the foregoing possible embodiments of the first aspect, the reference time of the reference base station is a time provided by a Global Navigation Satellite System (GNSS) GNSS timing, or a second The time provided by the 1588 1588V2 grant, or the time provided by the time information protocol NTP grant, or the time provided by the simple time information protocol SNTP grant, or the time provided by the second edition 1588 adaptive clock recovery 1588V2ATR grant.

In a seventh possible embodiment, in combination with the sixth possible embodiment of the first aspect, the device further comprises:

a second receiving module, configured to receive an extended buffer when a reference time of the reference base station is a time provided by a time information protocol NTP grant, or a time provided by a simple time information protocol SNTP grant, or a time provided by a base station of a 1588 V2 ATR grant The message, the extended cache message is used to indicate that the to-be-synchronized base station expands the first-in first-out queue FIFO of the to-be-synchronized base station.

In an eighth possible embodiment, in combination with the third possible embodiment of the first aspect,

The synchronization module is further configured to perform absolute time synchronization with the candidate base station, where the candidate base station is a base station that replaces the failed base station, wherein the device and the candidate reference are The manner in which the base station performs absolute time synchronization is the same as the manner in which the apparatus performs absolute time synchronization with the reference base station.

In a ninth possible embodiment, in combination with the eighth possible embodiment of the first aspect, the device further comprises:

An execution module, configured to perform transmission of a broadcast multicast service with a broadcast multicast service center BMSC device.

In a second aspect, an embodiment of the present invention provides a synchronization apparatus, where the apparatus is applied to a base station to be synchronized, and the base station to be synchronized is a base station that synchronizes with a frame number of a reference base station and a frame timing, and the reference base station is a The base station to be synchronized provides a base station with a reference time, a reference frame number, and a reference frame timing, and the apparatus includes:

a memory for storing information including program instructions;

a processor, coupled to the memory, for controlling execution of the program instruction, specifically for obtaining a first frame number and a first frame timing, where the first frame number is the to-be-synchronized base station and the reference frame a frame number after synchronization, the first frame timing is a frame timing after the base station to be synchronized is synchronized with the reference frame timing; obtaining time information by the first timing device, and obtaining a second frame number according to the time information And a second frame timing; obtaining a frame number deviation by using the first frame number and the second frame number; and obtaining a frame timing deviation by using the first frame timing and the second frame timing; according to the frame The number deviation and the frame timing deviation are synchronized with the reference time of the reference base station.

In a first possible embodiment, in combination with the second aspect, when the time information includes a Coordinated Universal Time UTC time, the processor is further configured to acquire a UTC time provided by the timing device; Converting the UTC time to a global positioning system GPS time; converting the GPS time to the second frame number and the second frame timing.

In a second possible embodiment, combining the second aspect or the first possible one of the second aspect Embodiment,

The processor is further configured to convert the frame number deviation and the frame timing deviation into a time difference value; and the time information is calibrated by the time difference to complete absolute time synchronization with the reference base station.

In a third possible embodiment, in combination with any one of the foregoing possible embodiments of the second aspect or the second aspect, the device further includes: a receiver;

The receiver is configured to receive the alarm information sent by the reference base station, where the alarm information is used to indicate that the time difference is greater than or equal to a predetermined time difference.

In a fourth possible embodiment, in combination with any one of the above possible embodiments of the second aspect or the second aspect,

The processor is further configured to synchronize the device to the first reference source to complete frequency synchronization with the reference base station, where the first reference source is the same as the reference source synchronized with the reference base station.

In a fifth possible embodiment, in combination with the second aspect or the possible embodiment of any one of the first to third aspects of the second aspect,

The processor is further configured to synchronize the device with a second reference source to determine a frequency offset between the device and the reference base station, where the second reference source is different from a reference source synchronized with the reference base station When the frequency deviation is less than the predetermined frequency deviation, synchronization with the second reference source continues.

In a sixth possible embodiment, in combination with any one of the foregoing possible embodiments of the second aspect or the second aspect, the reference time of the reference base station is a time provided by the Global Navigation Satellite System (GNSS) GNSS timing, or a second The time provided by the 1588 1588V2 grant, or the time provided by the time information protocol NTP grant, or the time provided by the simple time information protocol SNTP grant, or the time provided by the second edition 1588 adaptive clock recovery 1588V2ATR grant.

In a seventh possible embodiment, in combination with the second aspect or the third possible embodiment of the second aspect, the device further includes:

The receiver is further configured to: when the reference time of the reference base station is the time provided by the time information protocol NTP grant, or the time provided by the simple time information protocol SNTP grant, or the time provided by the base station of the 1588V2 ATR grant, the receiving extension The cached message is used to indicate that the to-be-synchronized base station expands the first-in first-out queue FIFO of the to-be-synchronized base station.

In an eighth possible embodiment, in combination with the second aspect or the third possible embodiment of the second aspect,

The processor is further configured to perform absolute time synchronization with the candidate base station, where the candidate base station is a base station that replaces the failed base station, wherein the device and the candidate reference are The manner in which the base station performs absolute time synchronization is the same as the manner in which the apparatus performs absolute time synchronization with the reference base station.

In a ninth possible embodiment, in combination with the second aspect or the eighth possible embodiment of the second aspect,

The processor is further configured to perform transmission of a broadcast multicast service with a broadcast multicast service center BMSC device.

In a third aspect, an embodiment of the present invention provides a synchronization method, where the method is applied to a base station to be synchronized, where the base station to be synchronized is a base station that synchronizes with a frame number of a reference base station and frame timing, and the reference base station is a The base station to be synchronized provides a base station with a reference time, a reference frame number, and a reference frame timing, and the method includes:

The base station to be synchronized obtains a first frame number and a first frame timing, where the first frame number is a frame number after the base station to be synchronized is synchronized with the reference frame number, and the first frame timing is the a frame timing after the synchronization base station synchronizes with the reference frame timing;

The base station to be synchronized acquires time information by using the first timing device, and obtains a second frame number and a second frame timing according to the time information;

The base station to be synchronized obtains a frame number deviation by using the first frame number and the second frame number; Passing the first frame timing and the second frame timing to obtain a frame timing deviation;

The base station to be synchronized completes synchronization with the reference time of the reference base station according to the frame number deviation and the frame timing deviation.

In a first possible embodiment, in conjunction with the third aspect, when the time information includes a Coordinated Universal Time UTC time, the to-be-synchronized base station acquires time information by using a first timing device, and obtains a second according to the time information. Frame number and second frame timing, including:

The base station to be synchronized acquires a UTC time provided by the timing device;

Converting the UTC time into a global positioning system GPS time in combination with leap second information;

Converting the GPS time to the second frame number and the second frame timing.

In a second possible embodiment, in combination with the third aspect or the first possible embodiment of the third aspect, the base station to be synchronized completes and according to the frame number deviation and the frame timing deviation Base time synchronization of the base station, including:

The base station to be synchronized converts the frame number deviation and the frame timing deviation into a time difference value;

The base station to be synchronized performs calibration on the time information by using the time difference to complete absolute time synchronization with the reference base station.

In a third possible embodiment, in combination with the second possible embodiment of the third aspect, after the base station to be synchronized converts the frame number offset and the frame timing offset into a time difference value, the method Also includes:

The base station to be synchronized receives the alarm information sent by the reference base station, and the alarm information is used to indicate that the time difference is greater than or equal to a predetermined time difference.

In a fourth possible embodiment, in combination with the third aspect or the first possible embodiment of the third aspect, before the obtaining, by the to-be-synchronized base station, the first frame number and the first frame timing, the method further include:

The base station to be synchronized is synchronized with the first reference source to complete the same frequency as the reference base station Step, the first reference source is the same as the reference source synchronized with the reference base station.

In a fifth possible embodiment, in combination with the third aspect or any one of the first to third aspects of the third aspect, obtaining, by the base station to be synchronized, the first frame number and the first frame Before timing, the method further includes:

The base station to be synchronized is synchronized with the second reference source to determine a frequency offset between the base station to be synchronized and the reference base station, and the second reference source is different from the reference source synchronized by the reference base station;

When the frequency deviation is less than a predetermined frequency deviation, the to-be-synchronized base station continues to synchronize with the second reference source.

In a sixth possible embodiment, in conjunction with any one of the foregoing possible embodiments of the third aspect or the third aspect, the reference time of the reference base station is a time provided by the Global Navigation Satellite System (GNSS) GNSS timing, or a second The time provided by the 1588 1588V2 grant, or the time provided by the time information protocol NTP grant, or the time provided by the simple time information protocol SNTP grant, or the time provided by the second edition 1588 adaptive clock recovery 1588V2ATR grant.

In a seventh possible embodiment, in combination with the sixth possible embodiment of the third aspect, when the reference time of the reference base station is the time provided by the time information protocol NTP grant, or the simple time information protocol SNTP timing When the time provided, or the time provided by the base station of the 1588 V2 ATR timing, the method further includes:

The base station to be synchronized receives the extended cache message, and the extended cache message is used to indicate that the base station to be synchronized expands the first-in first-out queue FIFO of the base station to be synchronized.

In an eighth possible embodiment, in conjunction with the third possible embodiment of the third aspect, the communication system further includes an alternative reference base station, the alternate reference base station being a reference to the failed base station After the base station to be synchronized receives the alarm information sent by the reference base station, the method further includes:

Performing absolute time synchronization between the base station to be synchronized and the candidate base station, wherein the to-be-synchronized The manner in which the step base station performs absolute time synchronization with the candidate base station is the same as the manner in which the base station to be synchronized performs absolute time synchronization with the reference base station.

In a second possible embodiment, in combination with any one of the foregoing possible embodiments in the third aspect or the third aspect, the base station to be synchronized is completed according to the frame number deviation and the frame timing deviation After the reference time synchronization of the reference base station, the method further includes:

The base station to be synchronized performs transmission of a broadcast multicast service with a broadcast multicast service center BMSC device.

The synchronization apparatus and method provided by the embodiment of the present invention, when the synchronization base station is in the frame number synchronization and the frame timing synchronization state with the reference base station, the obtaining module obtains the first frame number and the first frame timing, and then obtains the acquisition module. The time information provided by the timing device of the base station to be synchronized obtains the second frame number and the second frame timing converted by the time information, and the calculation module obtains the frame number deviation of the first frame number and the second frame number and the first frame timing And the frame timing deviation of the second frame timing, and then the synchronization module completes the absolute time synchronization with the reference base station by the frame number deviation and the frame timing deviation. The reference base station is a reference base station for performing absolute time synchronization with the base station to be synchronized, and the base station to be synchronized only needs to perform absolute time synchronization with the reference base station, instead of receiving a GPS signal by using a costly timing scheme, Absolute time synchronization between base stations, thereby avoiding the problem that in the prior art, in order to achieve absolute time synchronization between base stations, all base stations (base base station and base station to be synchronized) need to receive GPS signals with high cost timing scheme, resulting in high cost, that is, The cost of deploying a base station is reduced while achieving absolute time synchronization between base stations.

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 embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a network architecture diagram applicable to an embodiment of the present invention;

2 is a schematic diagram of a logical structure of a synchronization apparatus according to an embodiment of the present invention;

3 is a schematic diagram of a logical structure of another synchronization device according to an embodiment of the present invention;

4 is another network architecture diagram applicable to an embodiment of the present invention;

FIG. 5 is a schematic diagram of another network architecture applicable to an embodiment of the present invention; FIG.

6(a) is a schematic diagram of frequency synchronization between base stations according to an embodiment of the present invention;

FIG. 6(b) is a schematic diagram of frequency synchronization between base stations according to an embodiment of the present invention;

FIG. 6(c) is a schematic diagram of a frame number synchronization between a base station and a frame timing according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a logical structure of a synchronization apparatus according to an embodiment of the present invention;

FIG. 8 is a flowchart of a synchronization method according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The terms "component", "module", "system" and the like, as used in this specification, are used to mean a computer-related entity, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and a computing device can be a component. One or more components can reside within a process and/or execution thread, and the components can be located on one computer and/or distributed between two or more computers. Moreover, these components can execute from various computer readable media having various data structures stored thereon. A component may, for example, be based on signals having one or more data packets (eg, data from two components interacting with another component between the local system, the distributed system, and/or the network, such as the Internet interacting with other systems) Communicate through local and/or remote processes.

The technical solution of the present invention can be applied to various communication systems, for example, GSM (Global System of Mobile Communication), CDMA (Code Division Multiple Access) system, WCDMA (Wideband Code Division Multiple) Access, Wideband Code Division Multiple Access), GPRS (General Packet Radio Service), LTE (Long Term Evolution), etc.

A UE (User Equipment, UE), which may also be called a mobile terminal, a mobile user equipment, or the like, may be connected to one or more via a radio access network (for example, a RAN (Radio Access Network) The core network communicates, and the user equipment can be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal, for example, can be portable, pocket, handheld, computer built, or in-vehicle Mobile devices that exchange language and/or data with a wireless access network.

The base station may be a BTS (Base Transceiver Station) in GSM or CDMA, or a NodeB in WCDMA, or an eNB (evolved Node B, evolved base station) in LTE. limited.

Synchronization mainly includes system clock synchronization and frame synchronization, wherein system clock synchronization refers to synchronization (bit timing) of internal running clocks of all devices, and frame synchronization refers to synchronization of frame signals for communication between base stations (ie, frame timing synchronization). After the clock synchronization is completed between the base stations, the frequency is synchronized, and there is no relative phase drift between the base stations. However, when the frame number synchronization and the frame timing synchronization are not completed between the base stations, the timing relationship between the base stations is still random, that is, the frames. The number has a deviation from the frame timing but remains stable. That is to say, to complete the strict synchronization between the base stations, it is necessary to ensure that the starting phases of the frames of the base stations are consistent on the basis of completing the clock synchronization.

In addition, some broadcast multicast services, such as eMBMS (evolved Multimedia Broadcast and Multicast Service), require not only strict frame number and frame timing synchronization between base stations, but also base stations and BMSCs (Broadcast Multicast Service Center, Broadcast Multicast Service Center) Time synchronization of service content between devices.

1 is a network architecture diagram to which the present invention is applied, and FIG. 1 shows a mobile communication network system requiring synchronization between base stations.

As can be seen from FIG. 1, there are three base stations that need to be synchronized, namely, the base station 108, the base station 109, and the base station 110. Two UEs are a reference UE 111 and a reference UE 112, respectively. The base station 108 is a base station that receives the signals transmitted by the BITS 101 and the NTP-Server 102 through the transmission network and receives the GPS signals 106. The base station 109 and the base station 110 are base stations that receive signals transmitted by the BITS (Building Integrated Timing System) 101 and the NTP-Server (Network Time Protocol Server) 102 through the transmission network. The reference UE is a UE capable of communicating with two base stations at the same time. The GPS signal 106 may be a signal sent by a GNSS device, or may be a signal sent by a 1588V2 (1588 Version 2, 2nd Edition 1588) device.

It can also be seen from FIG. 1 that the mobile communication network system may further include a BITS 101, an NTP-Server 102, a network management node 103, a collaboration device 104, and an EPC (Evolved Packet Core) 105. The BITS 101 is used to provide frequency synchronization information (base station 109, base station 110) to the base station, and NTP-Server 102 is used for time synchronization information provided to the base station. The network management node 103 is for managing various devices included in the mobile communication system. The collaboration device 104 can be deployed as a separate device, or can be deployed as a logic module on the network management node 103, the EPC 105, or any base station (such as the base station 108, the base station 109, and the base station 110). It should be understood that the above is merely an example for convenience of description, and network nodes, base stations, and other devices in a communication network are not limited to the above types and numbers.

The base station 108, the base station 109, and the base station 110 need to complete the inter-base station reference time synchronization. The synchronization process may be initiated by the coordination device 104, or may be initiated by the upper-layer network element such as the network management node 103, or initiated by the base station that needs to synchronize. First, the acquired base station (base station 108, base station 109, and base station 110) receives the time when the reference UE transmits the synchronization reference signal, and completes frame number synchronization and frame timing synchronization between the three base stations. The base station 108 is a reference base station, and the reference base station is a base station to be synchronized. A base station providing a reference time, a reference frame number, and a reference frame timing; the base station 109 and the base station 110 are both base stations to be synchronized, and the base station to be synchronized is a base station synchronized with the frame number of the reference base station and frame timing synchronization. Therefore, the base station 109 and the base station 110 are required to complete frame number synchronization and frame timing synchronization with the base station 108, respectively. Then, the absolute time of the three base stations is obtained, the time difference between the base station 108 and the base station 109 is determined by the absolute time of the three base stations, and the time difference between the base station 108 and the base station 110, and the obtained two time differences are obtained. The value, the reference time synchronization between the base station 109 and the base station 108 is completed, and the reference time synchronization between the base station 110 and the base station 108 is completed.

By selecting one base station as the reference base station and the other base stations as the base station to be synchronized, then the base station to be synchronized needs only to perform absolute time synchronization with the reference base station, so that in order to achieve strict synchronization between the base stations, it is not necessary to base all base stations. Both use high-precision time timing methods such as GNSS timing, which reduces the cost of deploying base stations.

As shown in FIG. 2, a device 20 that performs a synchronization method in a mobile communication system. That is, a synchronizing device 20. The device 20 corresponds to the base station 109 to be synchronized or the base station 110 to be synchronized shown in FIG. 1. The base station to be synchronized is a base station that synchronizes with the frame number of the reference base station and the frame timing, and the reference base station provides a reference time and a reference to the base station to be synchronized. Base station with frame number and reference frame timing. The device 20 includes an obtaining module 201, an obtaining module 202, a calculating module 203, and a synchronizing module 204.

The obtaining module 201 is configured to obtain a first frame number and a first frame timing, and provide the first frame number and the first frame timing to the calculation module 203, where the first frame number is a frame after the base station to be synchronized is synchronized with the reference frame number. No., the first frame timing is the frame timing after the base station to be synchronized synchronizes with the reference frame timing.

The obtaining module 203 is configured to acquire time information by using the first timing device, and provide the time information to the obtaining module 201, where the first timing device is configured to provide the device 20 with time information.

The obtaining module 201 is further configured to obtain the second frame number and the second frame timing according to the time information, and provide the second frame number and the second frame timing to the calculation module 203.

It can be seen that the second frame number is the frame number obtained by the time information conversion, and the second frame timing is the frame timing obtained by the time information conversion.

The calculating module 203 is configured to obtain a frame number deviation by using the first frame number and the second frame number; and obtain a frame timing deviation by using the first frame timing and the second frame timing, and provide the frame number deviation and the frame timing deviation to the synchronization Module 204.

The synchronization module 204 is configured to complete the reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation.

When the synchronization base station is in the frame number synchronization and the frame timing synchronization state with the reference base station, the obtaining module obtains the first frame number and the first frame timing, and then obtains the synchronization to be synchronized by the acquisition module. The time information provided by the timing device of the base station obtains the second frame number and the second frame timing converted by the time information, and the calculation module obtains the frame number deviation of the first frame number and the second frame number, and the first frame timing and the first frame timing The frame timing deviation of the two frame timing is further synchronized by the synchronization module with the reference time of the reference base station by the frame number deviation and the frame timing deviation. The reference base station is a reference base station for performing reference time synchronization with the base station to be synchronized, and the base station to be synchronized only needs to perform absolute time synchronization with the reference base station, instead of receiving a GPS signal by using a costly timing scheme, Base station synchronization time synchronization, thereby avoiding the problem that in the prior art, in order to achieve reference time synchronization between base stations, all base stations (base base station and base station to be synchronized) need to receive GPS signals by using a costly timing scheme, resulting in high cost, that is, The cost of deploying the base station is reduced while achieving reference time synchronization between the base stations.

Further, the present invention may further provide another synchronization device 30. As shown in FIG. 3, the obtaining module 201 in the device 30 includes an obtaining unit 2011 and a converting unit 2012. The synchronization module 204 includes a converting unit 2041 and a calibration unit. 2042, and the device 30 further includes: a first receiving module 205, a second receiving module 206, and an executing module 207.

Wherein, when the time information includes the Coordinated Universal Time UTC time, the obtaining unit 2011 in the obtaining module 201 is configured to acquire the UTC time provided by the timing device, and provide the UTC time to the converting unit 2012; then the converting unit 2012 is configured to combine The leap second information converts the UTC time into GPS time; converts the GPS time into a second frame number and a second frame timing.

Among them, GPS time is atomic time, UTC time is astronomical time, and leap second information can be regarded as the difference information between atomic time and astronomical time. The leap second information changes as the deviation between astronomical time and atomic time changes. For example, the current leap second information is 19s.

For LTE, the starting time of the GPS time epoch is generally used as the starting time of the LTE frame timing, that is, the corresponding LFN (LTE Frame Number) = 0, LFN increases by 1 every 10ms, counts to 1023 and then 10ms, LFN value returns to 0 from the beginning. Therefore, each GPS moment has a corresponding unique LFN time value.

The conversion of the GPS time into a frame number (LFN) is specifically: the total number of seconds of the GPS (relative to the GPS era start time) * 100 is obtained, and then the total number of seconds is modulo 1024 to obtain the frame number (LFN). ).

Further, the converting unit 2041 in the synchronization module 204 is configured to convert the frame number deviation and the frame timing deviation into a time difference value, and provide the time difference value to the calibration unit 2042; the calibration unit 2042 is configured to pass the time difference value pair The time information is calibrated to complete the reference time synchronization with the reference base station.

After obtaining the second frame number and the first frame number in the above manner, the frame number deviation between the reference base station and the device 30 is calculated; and the frame timing between the reference base station and the device 30 is obtained by the first frame timing and the second frame timing. Deviation, such as the first frame number is 225 frames, the second frame number is 200 frames, the first frame timing is 15 ms, and the second frame timing is 5 ms, the frame number deviation between the reference base station and the to-be-synchronized base station is 25 frames, The frame timing deviation is 10 ms, so that the time difference between the reference base station and the to-be-synchronized base station (device 30) is 250 ms, which means that the time to be acquired by the base station to be synchronized is 250 ms shorter than the precise time acquired by the base station.

Further, when the time difference is greater than or equal to the predetermined time difference, the first receiving module 205 is configured to receive the alarm information sent by the reference base station, where the alarm information is used to indicate that the time difference is greater than or equal to the predetermined time difference. It can be understood that after the device 30 receives the alarm information, the synchronization operation with the reference base station can be stopped.

The frame number (LFN) has a period of 10.24 s. When the UTC time is converted, the GPS time is Accurate GPS time difference in the case of +/-5.12s will result in a jump and thus can not accurately obtain the specific deviation of the GPS time and the accurate GPS time obtained by UTC time conversion, so it is impossible to obtain the accurate synchronization of the station to be synchronized. Absolute time. In the present invention, the predetermined time difference is 5.12 s.

In the present invention, the size of the time difference between the reference base station and the base station to be synchronized and the predetermined time difference is broken by the reference base station. When the reference base station receives the GNSS grant or receives the 1588V2 grant, and also receives the NTP grant or the SNTP grant or the 1588V2ATR grant, the reference base station can thereby obtain the time difference and compare the time difference with the predetermined time difference. When the predetermined time difference is greater than or equal to, the alarm information is reported.

It should be noted that, in the cooperative device shown in FIG. 1, the cooperative device determines the reference base station and the base station to be synchronized before the device 30 (the base station to be synchronized) is in the frame number synchronization and frame timing synchronization state with the reference base station (for convenience) Description, the device 30 is uniformly described by the base station to be synchronized):

Determining at least one synchronization packet, each synchronization packet including at least two base stations; determining a reference base station and a base station to be synchronized from among at least two base stations included in each synchronization packet.

There are various ways to determine the reference base station and the base station to be synchronized, and two methods are listed here.

The first mode: the cooperative device determines, from the at least one synchronization packet, the base station that receives the high-precision time grant as the reference base station; and determines that the base station other than the reference base station is the base station to be synchronized.

The high-precision time grant may include a GNSS grant and a 1588V2 grant. When the synchronization packet includes a base station that receives the GNSS grant and/or a base station that receives the 1588V2 grant, the cooperative device determines, from the at least one synchronization packet, the base station that receives the GNSS grant. The base station that is the reference base station or receives the 1588V2 timing is the reference base station. That is, the reference time of the reference base station is the time provided by the GNSS grant, or the time provided by the 1588V2 grant. It can be obtained that when the second timing device is represented as providing time information to the reference base station, the second timing device may be a device adopting GNSS or a device of 1588V2.

Generally, a base station that receives high-precision time timing and a base station that receives low-precision time timing are included in the synchronization packet. Low-precision time timing can include NTP (Network Time Protocol) Time-rate, SNTP (Simple Network Time Protocol), 1588V2ATR (1588V2 Adaptive Time Recovery, second edition 1588 adaptive clock recovery) timing, it is determined from the synchronization packet that only NTP timing is received, and/or The SNTP grants time, and/or the base station receiving the 1588V2 ATR grant is the base station to be synchronized. That is, the base station to be synchronized is a base station that cannot receive GNSS grant and/or 1588V2 grant time.

It should be noted that two or more base stations receiving high-precision time timing may be included in one synchronization packet, and other high-precision time-time base stations are selected after the cooperative device selects one of the base stations receiving the high-precision time grant as the reference base station. For the base station to be synchronized. However, in order to consider the problem of deploying the cost of the base station, the general cooperative device may consider to avoid dividing a plurality of base stations receiving high-precision time timing into the same synchronization packet when dividing the synchronization packet.

The second mode: the coordination device determines any one of the base stations as the reference base station from the at least one synchronization packet; and determines that the base station other than the reference base station is the base station to be synchronized.

When the second mode is adopted, as shown in FIG. 4, the network architecture diagram shown in FIG. 4 does not include the base station that determines the receiving GNSS grant as the base station, and/or the base station that receives the 1588V2 grant, and cooperates. The device determines from the synchronization packet that any one of the base stations is the reference base station (ie, the reference time provided by the reference base station is the time provided by the NTP grant, or the time provided by the SNTP grant, or the time provided by the 1588 V2 ATR grant). The synchronization packet includes a base station that cannot receive the GNSS grant, and/or a base station that cannot receive the 1588V2 grant (ie, a base station that only receives the NTP grant, and/or the SNTP grant, and/or the 1588V2 ATR grant). Further, the remaining base stations in the synchronization packet are determined to be base stations to be synchronized. Comparing FIG. 4 with FIG. 1, it is found that FIG. 4 does not include the device 106 that transmits the GPS signal to the base station 108. Therefore, the base station 108, the base station 109, or the base station 110 can all serve as the reference base station.

In another embodiment, the coordination device determines an alternate reference base station from at least one synchronization packet, the alternate reference base station being a base station replacing the reference base station in which the error occurred. As shown in FIG. 5, the network architecture further includes a GPS signal 113 (ie, a device 113 that transmits a GPS signal), and to the base station 110. A GPS signal 113 is sent. The base station 110 can then serve as an alternate base station.

Correspondingly, when the base station fails, the base station to be synchronized performs reference time synchronization with the candidate base station, wherein the manner in which the base station to be synchronized and the candidate base station perform reference time synchronization are synchronized with the base station to be synchronized and the reference base station. The same way. That is, the synchronization module 204 is further configured to perform the reference time synchronization between the device 30 and the candidate reference base station, wherein the manner in which the device 30 performs the reference time synchronization with the candidate reference base station is the same as the manner in which the device performs the reference time synchronization with the reference base station.

Alternatively, referring to FIG. 1, although the base station 110 shown in FIG. 1 cannot receive GPS signals, it can still serve as an alternative base station.

It can be understood that the candidate base station can be a base station receiving GNSS timing, or a base station receiving 1588V2 timing, or a base station receiving only NTP timing, and/or SNTP timing, and/or 1588V2 ATR timing.

In another implementation manner, it is worth noting that the cooperative device participates in realizing the frame number and frame timing of the base station to be synchronized relative to the reference base station by acquiring the time at which the reference base station and the to-be-synchronized base station receive the uplink synchronization reference signal. Synchronization, thereby achieving the frame number synchronization and frame timing synchronization state of the device 30 (base station to be synchronized) and the reference base station.

The cooperative device first determines the reference UE, and then determines a timing offset between the base station to be synchronized and the reference base station according to the time when the reference base station and the base station to be synchronized receive the uplink synchronization reference signal sent by the reference UE; and calibrates the base station to be synchronized according to the timing deviation After the calibration, the base station to be synchronized obtains the first frame number and the first frame timing, and completes synchronization of the frame number and frame timing of the base station to be synchronized with respect to the reference base station.

The method for determining the timing deviation between the base station to be synchronized and the reference base station according to the time when the reference base station and the base station to be synchronized receive the uplink synchronization reference signal sent by the reference UE may be various. The present invention lists two methods herein. :

The first way:

First, the cooperative device receives the relative time T1 sent by the reference base station, where the relative time T1 is the time when the reference base station determined by the reference base station determines the synchronization reference signal sent by the reference UE according to the current frame number and the frame timing.

The synchronization reference signal sent by the reference UE includes, but is not limited to, at least one of the following: a PRACH (Physical Random Access Channel), a SRS (Sounding Reference Signal), and a DMRS (Demodulation Reference) Signal, demodulation reference signal).

Second, the cooperative device receives the relative time T2 sent by the base station to be synchronized, and the relative time T2 is the time at which the base station to be synchronized, which is determined by the current frame number of the base station to be synchronized and the frame timing, receives the synchronization reference signal sent by the reference UE.

Third, the coordination device determines the timing deviation ΔT based on the relative time T1 and the relative time T2. Where ΔT=T1-T2.

The cooperative device can determine the offset of the respective time axes of the two base stations by the difference between the two relative moments, that is, the frame number of the two base stations and the frame timing deviation. The base station to be synchronized can adjust its own frame number and frame timing according to the ΔT, thereby achieving synchronization with the frame number and frame timing of the reference base station.

The second way:

First, the coordination device determines an RTD (Round-Trip Delay Loop) measurement result TA1 of the reference UE and the reference base station.

Second, the coordination device determines the RTD measurement result TA2 of the reference UE and the base station to be synchronized.

Third, the coordination device determines the deviation TA1-TA2 caused by the distance difference between the reference UE and the base station to be synchronized and the base station to be synchronized according to the measurement result TA1 and the measurement result TA2.

Fourth, the cooperative device obtains the relative time T1 and the relative time T2 by the first method, and determines the timing deviation ΔT according to the deviation TA1-TA2, the relative time T1, and the relative time T2. Where ΔT=T1-T2-(TA1-TA2).

Since the distance between the reference UE and the base station to be synchronized may be different, the above ΔT=T1-T2 cannot reflect the timing deviation introduced by the difference between the distance between the UE and the base station to be synchronized, and thus the reference UE to the reference base station and The difference in the distance of the base station to be synchronized is introduced into the timing offset, so that a more accurate timing deviation can be obtained.

Further optionally, the synchronization module 204 is further configured to synchronize the device 30 with the first reference source to complete frequency synchronization with the reference base station, where the first reference source is the same as the reference source synchronized with the reference base station. For example, the base station to be synchronized synchronizes to the same reference source (the GPS signal 106 and the GPS signal 107 are GPS signals) through the line clock (bits shown in FIG. 1), and the frequency synchronization between the base station to be synchronized and the reference base station is completed. The phase shift between the base stations is made uniform.

The reference source can be GPS, atomic clock, crystal oscillator, and the like.

6(a), 6(b) and 6(c) are diagrams showing frequency synchronization between base stations according to an embodiment of the present invention.

The system clocks of the two base stations (base station 1 and base station 2) that do not perform inter-base station frequency synchronization operate at f1 and f2, respectively, where f1≠f2, as shown in FIG. 6(a), which is the base station 1 and the base station 2 The frame number is independent of the frame timing, and the clock drift speed of the base station 1 and the base station 2 differs depending on f1≠f2.

The two base stations are synchronized to the same clock reference source, and frequency synchronization between the base stations can be achieved. If both base stations are synchronized to the BITS, the frequencies of the two base stations transmitting the radio frames are synchronized (ie, f1 = f2), so there is no relative phase drift, that is, the frame number and frame timing deviation remain stable. Since the BITS has only frequency information, the timing relationship between the two base stations is still random. As can be seen from Figure 6(a), the inter-base station frame number and frame timing are still staggered and do not reach strict synchronization. Figure 6(b) shows the frame phase relationship of the two base stations after the completion of the frame number and frame timing synchronization. Combining the measurement of the frame timing deviation, taking FIG. 6(a) and FIG. 6(b) as an example, the base station 1 is the reference base station, the base station 2 is the base station to be synchronized, and the phase relationship between the base station 1 and the base station 2 after frequency synchronization is completed ( b) shown. The base station 1 and the base station 2 receive the synchronization reference signal transmitted by the reference UE, and the base station 1 and the base station 2 respectively based on their own frame number and frame timing. Synchronization, determining the relative time T1 and the relative time T2 of the uplink access signal received by the UE, thereby obtaining the timing deviation ΔT, and the base station 2 performs calibration according to ΔT to complete the synchronization of the frame number and the frame timing with respect to the base station 1, as shown in FIG. 6 c) shown.

Further optionally, the synchronization module 204 is further configured to synchronize the device 30 with the second reference source to determine a frequency offset between the base station to be synchronized and the reference base station, where the reference source of the second reference source is different from the reference base station; When the deviation is less than the predetermined frequency deviation, synchronization with the second reference source continues. That is, when the reference base station and the to-be-synchronized base station are different reference sources through the line clock synchronization reference source, the frequency deviation between the base station to be synchronized and the reference base station is less than or equal to a predetermined frequency deviation. The present invention does not limit the predetermined frequency deviation, for example, the predetermined frequency deviation may be 3*10E-11. The predetermined frequency deviation is mainly related to the selection of the test period for synchronizing the frame number and the frame timing between the base stations. For example, when the test period is accelerated, the predetermined frequency deviation may be correspondingly increased.

It should be noted that when the reference base station and the base station to be synchronized use different reference sources, the two reference sources need to meet the condition that a high-precision reference source is required. For example, the reference base station uses GPS as a reference source, and the base station to be synchronized uses BITS as a reference source, then the BITS uses a high-precision atomic clock as a clock reference, thereby ensuring phase drift between the reference base station and the base station to be synchronized. Within a small range.

Further, the second receiving module 206 is configured to: when the reference base station is a base station that only receives the time information protocol NTP grant, and/or the simple time information protocol SNTP grant, and/or the 1588V2ATR grant, receives the extended cache message, and expands The cache message is used to indicate that the base station to be synchronized expands the FIFO (First Input First Output) of the base station to be synchronized.

Correspondingly, after the second receiving module 206 receives the extended buffer message, the FIFO is converted from a normal state to an expanded state, so as to cope with the time deviation existing between the BMSC device and the base station to be synchronized. When the base station to be synchronized (device 30) completes the traffic transmission with the BMSC device, the FIFO transitions from the expanded state to the normal state.

It should be noted that the extended cache message is sent by the collaboration device.

Correspondingly, for the reference base station, the coordination device also sends an extended buffer message to the reference base station for instructing the reference base station to expand the FIFO of the reference base station.

It should be noted that in this manner, the reference base station is not a base station that receives GNSS grant time or receives 1588V2 grant time. At this time, strict frame number and frame timing synchronization between the reference base station and the base station to be synchronized in the same synchronization packet can be achieved, and strict time synchronization with each other can be achieved, but only the base station time and standard GPS time in the area. There is a fixed deviation. In this case, when encountering a service (such as eMBMS) that requires the base station to have an accurate absolute time, it is necessary to expand the FIFO of the base station. The effect of this bias is absorbed by expanding the FIFO (eg, enabling synchronization with eMBMS between BMSC devices).

Further optionally, after the synchronization module 204 completes the reference time synchronization with the reference base station, the executing module 207 is configured to perform transmission of the broadcast multicast service with the BMSC device.

It is worth noting that after the synchronization base station completes the reference time synchronization with the reference base station, the base station (between the reference base station and the base station to be synchronized) is strictly reference time synchronized. When the reference base station is a base station receiving GNSS grant or 1588V2 timing (using an accurate absolute time), when performing a service (such as eMBMS) requiring time synchronization of the service content, the BMSC device and the base station (including the reference base station and the to-be-synchronized) The time synchronization of the business content can be realized between the base stations. When the reference base station is a base station that cannot receive the GNSS grant and the 1588V2 grant time (which can be regarded as using an inaccurate absolute time), when performing a service (such as eMBMS) requiring time synchronization of the service content, the base station (including the base station and the base station and The base station to be synchronized needs to expand the FIFO to achieve time synchronization of the service content with the BMSC device.

As shown in FIG. 7, FIG. 7 is a schematic diagram of a hardware structure of a base station to be synchronized. The base station to be synchronized may include a memory 701, a processor 702, a receiver 703, and a bus 704, wherein the memory 701, the receiver 703, and the processor 702 are communicably connected through a bus 704.

The memory 701 may be a read only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). Save The storage 701 can store an operating system and other applications. When the technical solution provided by the embodiment of the present invention is implemented by software or firmware, the program code for implementing the technical solution provided by the embodiment of the present invention is stored in the memory 701 and executed by the processor 702.

The receiver 703 is used for communication between the device and other devices or communication networks such as, but not limited to, Ethernet, Radio Access Network (RAN), Wireless Local Area Network (WLAN), and the like.

The processor 702 can be a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits for executing related programs. The technical solution provided by the embodiment of the present invention is implemented.

Bus 704 can include a path for communicating information between various components of the device, such as memory 701, receiver 703, and processor 702.

It should be noted that although the hardware shown in FIG. 7 only shows the memory 701, the receiver 703 and the processor 702, and the bus 704, in the specific implementation process, those skilled in the art should understand that the terminal also includes the normal operation. Other devices necessary. At the same time, those skilled in the art will appreciate that hardware devices that implement other functions may also be included, depending on the particular needs.

Specifically, when the base station shown in FIG. 7 is used to implement the apparatus shown in the embodiment of FIG. 2 to FIG. 3, the processor 702 in the apparatus is coupled to the memory 701 and the receiver 703 for controlling execution of program instructions. Specifically, the first frame number and the first frame timing are obtained, where the first frame number is a frame number after the base station to be synchronized and the reference frame number are synchronized, and the first frame timing is a frame timing after the base station to be synchronized synchronizes with the reference frame timing; Obtaining time information by the first timing device; obtaining a second frame number and a second frame timing according to the time information; obtaining a frame number deviation by using the first frame number and the second frame number; and passing the first frame timing and the second frame timing Obtain a frame timing deviation; complete the reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation.

The obtaining, by the processor 702, the second frame number and the second frame timing may include: when the time When the information includes the UTC time, the processor 702 acquires the UTC time provided by the timing device; combines the leap second information to convert the UTC time into the global positioning system GPS time; converts the GPS time into the second frame number and the second frame timing.

And for the processor 702 to complete the reference time synchronization between the device and the reference base station, the method may include: the processor 702 converts the frame number deviation and the frame timing deviation into a time difference value; and calibrates the time information by using the time difference to complete the base station with the reference base station. The base time is synchronized.

Further, when the time difference is greater than or equal to the predetermined time difference, the receiver 703 is configured to receive the alarm information sent by the reference base station, where the alarm information is used to indicate that the time difference is greater than or equal to the predetermined time difference.

Further, the processor 702 is further configured to synchronize the device to the first reference source to complete frequency synchronization with the reference base station, where the first reference source is the same as the reference source synchronized with the reference base station.

Or further, the processor 702 is further configured to synchronize the device to the second reference source, determine a frequency offset between the device and the reference base station, and the second reference source is different from the reference source synchronized with the reference base station; when the frequency deviation is less than the predetermined frequency When the deviation occurs, it continues to synchronize with the second reference source.

It should be noted that the reference time of the reference base station in the present invention is the time provided by the GNSS GNSS grant time, or the time provided by the second version 1588 1588V2 grant time, or the time and simple time information protocol provided by the time information protocol NTP grant time. The time provided by the SNTP grant, the time provided by the second version of the 1588 adaptive clock recovery 1588V2ATR grant, that is, the base station that the base station receives for the receiving GNSS, or the base station that receives the 1588V2 grant, or only receives the NTP grant, and/or SNTP grant, And/or 1588V2ATR timing base station. The device (the base station to be synchronized) is a base station that cannot receive GNSS grants and/or 1588 V2 grants.

Further, the receiver 703 is further configured to: when the reference base station is a base station that only receives the time information protocol NTP grant, and/or the simple time information protocol SNTP grant, and/or the 1588V2ATR grant, receive the extended cache message, and expand the cache message. The FIFO indicating that the base station to be synchronized expands the base station to be synchronized.

Further, the processor 702 is further configured to perform a reference time synchronization between the device and the candidate reference base station, where the candidate base station is a base station that replaces the failed base station, where the device performs reference time synchronization with the candidate base station. The device performs the same reference time synchronization with the reference base station.

It can be understood that the candidate base station is a base station receiving GNSS timing, or a base station receiving 1588V2 timing, or a base station receiving only NTP timing, and/or SNTP timing, and/or 1588V2 ATR timing.

Further, the processor 702 is further configured to perform transmission of a broadcast multicast service with the BMSC device.

Therefore, according to the present invention, the cost problem of reducing the reference time synchronization between the base stations can be realized, and the service content synchronization between the BMSC and the base station can be realized at a low cost.

In connection with Figures 1-7 above, the present invention provides a synchronization method, as shown in Figure 8. The execution subject in the method is the base station to be synchronized 109 or the base station 110 to be synchronized shown in FIG. 1 , wherein the base station to be synchronized is a base station that synchronizes with the frame number of the reference base station and the frame timing, and the reference base station provides the base station to be synchronized. Base station with reference time, reference frame number, and reference frame timing.

801. The base station to be synchronized obtains a first frame number and a first frame timing, where the first frame number is a frame number after the base station to be synchronized is synchronized with the reference frame number, and the first frame timing is a frame after the base station to be synchronized synchronizes with the reference frame timing. timing.

It can be seen that, before the base station to be synchronized obtains the first frame number and the first frame timing, the to-be-synchronized base station is in the frame number synchronization and frame timing synchronization state with the reference base station.

The cooperative device is configured to complete the frame number and the frame timing synchronization between the base station and the to-be-synchronized base station, where the base station to be synchronized is a base station that needs to perform reference time synchronization with the reference base station, and the reference base station is used to complete and synchronize the base station to be synchronized. Reference base station synchronized between reference times.

802. The base station to be synchronized acquires time information by using the first timing device, and obtains a second frame number and a second frame timing.

The first timing device is configured to provide time information to the base station to be synchronized. As shown in FIG. 1, the first timing device included in the mobile communication network system to which the method is applicable is BITS 101 and/or NTP-Server 102.

803. The base station to be synchronized obtains a frame number deviation by using the first frame number and the second frame number; and obtains a frame timing deviation by using the first frame timing and the second frame timing.

804. The base station to be synchronized completes the reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation.

According to a synchronization method provided by the embodiment of the present invention, the base station to be synchronized obtains the time information obtained by the timing device of the base station to be synchronized by using the first frame number synchronized with the reference frame number and the first frame timing synchronized with the reference frame timing. The second frame number and the second frame timing, and then obtain the frame number deviation of the first frame number and the second frame number and the frame timing deviation of the first frame timing and the second frame timing, which are completed by the frame number deviation and the frame timing deviation Synchronized with the reference time of the reference base station. The reference base station is a reference base station for performing reference time synchronization with the base station to be synchronized, and the base station to be synchronized only needs to perform absolute time synchronization with the reference base station, instead of receiving a GPS signal by using a costly timing scheme, Base station synchronization time synchronization, thereby avoiding the problem that in the prior art, in order to achieve reference time synchronization between base stations, all base stations (base base station and base station to be synchronized) need to receive GPS signals by using a higher cost timing receiver, resulting in higher cost. That is, while realizing the reference time synchronization between the base stations, the cost of deploying the base station is reduced.

In another implementation manner, before the step 801, the cooperation device participates in the frame number synchronization and the frame timing synchronization of the base station to be synchronized with the reference base station, and the coordination device determines the reference base station and the base station to be synchronized.

The first way: the cooperative device determines to receive the high precision time timing from the at least one synchronization packet The base station is a reference base station; determining that the base station other than the reference base station is the base station to be synchronized.

Generally, a base station that receives high-precision time timing and a base station that receives low-precision time timing are included in the synchronization packet. The low-precision time grant can include NTP (Network Time Protocol), SNTP (Simple Network Time Protocol), and 1588V2 ATR (1588V2 Adaptive Time Recovery). It is determined from the synchronization packet that the base station that only receives the NTP grant, and/or the SNTP grant, and/or receives the 1588 V2 ATR grant is the base station to be synchronized. That is, the base station to be synchronized is a base station that cannot receive GNSS grant and/or 1588V2 grant time.

When the second mode is adopted, as shown in FIG. 4, the network architecture diagram shown in FIG. 4 does not include the base station that determines the receiving GNSS grant as the base station, and/or the base station that receives the 1588V2 grant, and cooperates. The device determines, from the synchronization packet, any one of the base stations as a reference base station (ie, base The reference time of the quasi-base station is the time provided by the NTP grant, or the time provided by the SNTP grant, or the time provided by the 1588V2 ATR grant). The synchronization packet includes a base station that cannot receive the GNSS grant, and/or a base station that cannot receive the 1588V2 grant (ie, a base station that only receives the NTP grant, and/or the SNTP grant, and/or the 1588V2 ATR grant). Further, the remaining base stations in the synchronization packet are determined to be base stations to be synchronized. Comparing FIG. 3 with FIG. 1, it is found that FIG. 3 does not include the device 106 that transmits the GPS signal to the base station 108. Therefore, the base station 108, the base station 109, or the base station 110 can all serve as the reference base station.

In another embodiment, the coordination device determines an alternate reference base station from at least one synchronization packet, the alternate reference base station being a base station replacing the reference base station in which the error occurred. As shown in FIG. 5, the network architecture further includes a GPS signal 113 (i.e., a device 113 that transmits a GPS signal) and transmits a GPS signal 113 to the base station 110. The base station 110 can then serve as an alternate base station.

The first way:

The synchronization reference signal sent by the reference UE includes, but is not limited to, at least one of the following: PRACH, SRS, DMRS.

The second way:

First, the coordination device determines the RTD measurement result TA1 of the reference UE and the reference base station.

In another implementation manner, before the step 801, the method further includes: synchronizing the base station to be synchronized with the first reference source to complete frequency synchronization with the reference base station, where the first reference source is synchronized with the reference source of the reference base station . For example, the base station to be synchronized synchronizes to the same reference source (the GPS signal 106 and the GPS signal 107 are GPS signals) through the line clock (bits shown in FIG. 1), and the frequency synchronization between the base station to be synchronized and the reference base station is completed. The phase shift between the base stations is made uniform.

In another implementation, before the step 801, the method further includes: the base station to be synchronized is synchronized with the second reference source, determining a frequency offset between the base station to be synchronized and the reference base station, and the second reference source is synchronized with the reference base station. The reference source is different; when the frequency deviation is less than the predetermined frequency deviation, synchronization with the second reference source continues. That is, when the reference base station and the to-be-synchronized base station are different reference sources through the line clock synchronization reference source, the frequency deviation between the base station to be synchronized and the reference base station is less than or equal to a predetermined frequency deviation. The present invention does not limit the predetermined frequency deviation, for example, the predetermined frequency deviation may be 3*10E-11. The predetermined frequency deviation is mainly related to the selection of the test period for synchronizing the frame number and the frame timing between the base stations. For example, when the test period is accelerated, the predetermined frequency deviation may be correspondingly increased.

It should be noted that when the reference base station and the base station to be synchronized adopt different reference sources, the two The condition that the reference source needs to meet is that a high-precision reference source is required. For example, the reference base station uses GPS as a reference source, and the base station to be synchronized uses BITS as a reference source, then the BITS uses a high-precision atomic clock as a clock reference, thereby ensuring phase drift between the reference base station and the base station to be synchronized. Within a small range.

It should be noted that the reference time of the reference base station in the present invention is the time provided by the GNSS GNSS grant time, or the time provided by the second version 1588 1588V2 grant time, or the time provided by the time information protocol NTP grant time, or simple time information. The time provided by the protocol SNTP grant, or the time provided by the second version of the 1588 adaptive clock recovery 1588V2ATR grant, that is, the base station that receives the GNSS grant as the base station, or the base station that receives the 1588V2 grant, or only receives the NTP grant, and/ Or base station with SNTP timing, and/or 1588V2ATR timing.

The base station to be synchronized is a base station that cannot receive GNSS grant and/or 1588 V2 grant (ie, a base station that only receives NTP grant, and/or SNTP grant, and/or 1588 V2 ATR grant). It can be obtained that the first timing device is a device using NTP, a device using SNTP, or a device adopting 1588V2 ATR.

Correspondingly, in another embodiment, in step 802, the time information provided by the base station to be synchronized to receive the first timing device may be GPS time, or may be UTC (Universal Time Coordinated) time. When the base station to be synchronized is a base station that only receives NTP grant and/or SNTP grant time, the time information is UTC time; when the base station to be synchronized is a base station that only receives 1588 V2 ATR grant time, the time information is GPS time.

In another embodiment, in step 802, the base station to be synchronized obtains the second frame number and the second frame timing by receiving time information provided by the first timing device, including:

Generally, the base stations to be synchronized are the base stations that receive the low-precision timing. Therefore, when the time of the base station to be synchronized is the time provided by the NTP grant, or the time provided by the SNTP grant, or the time provided by the 1588V2 ATR grant (that is, the base station to be synchronized only receives the NTP grant time) Base station, or only the base station receiving SNTP grant time (that is, the time information is UTC time), the base station to be synchronized receives the time through NTP Or, by UTC time of SNTP timing, combined with leap second information, the UTC time is converted into GPS time, and the GPS time is converted into a second frame number and a second frame timing. Among them, GPS time is atomic time, UTC time is astronomical time, and leap second information can be regarded as the difference information between atomic time and astronomical time. The leap second information changes as the deviation between astronomical time and atomic time changes. For example, the current leap second information is 19s.

When the base station to be synchronized is a base station that only receives 1588V2 ATR timing, the GPS time (time information) is obtained by receiving the timing of the device (first timing device) using the 1588V2 ATR, and then the GPS time is converted into the second frame number and the second. Frame timing.

Among them, protocols such as NTP and SNTP deliver UTC time and do not carry leap second information. In the UTC time and GPS time conversion, the current leap second information is needed to ensure the accuracy of the conversion. Therefore, it is necessary to provide corresponding leap second information to the base station through configuration to ensure that the time after conversion is accurate.

In another implementation, in step 803, the base station to be synchronized completes the reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation, and may include:

The base station to be synchronized converts the frame number deviation and the frame timing deviation into a time difference; the base station to be synchronized calibrates the time information by the time difference, and completes the reference time synchronization with the reference base station.

In another embodiment, after the step 803, after the base station to be synchronized converts the frame number deviation into the time difference value, the method may further include: the base station to be synchronized receives the alarm information sent by the reference base station, and the alarm information is used to indicate the time difference. The value is greater than or equal to the predetermined time difference. It can be understood that after the base station to be synchronized receives the alarm information, the synchronization operation with the reference base station can be stopped.

The frame number (LFN) has a period of 10.24 s. When the GPS time obtained by converting the UTC time is different from the accurate GPS time by +/- 5.12 s, it will result in a jump and thus can not accurately obtain the UTC time. The GPS time is accurate with the exact GPS time, so the exact time of the station to be synchronized cannot be obtained. In the present invention, the predetermined time difference is 5.12 s.

In the present invention, the time difference between the reference base station and the base station to be synchronized is broken by the reference base station and the pre- The size between the time differences. Because, as shown in FIG. 1, FIG. 4 or FIG. 5, when the reference base station receives the GNSS grant or receives the 1588V2 grant, and also receives the NTP grant or the SNTP grant or the 1588V2ATR grant, the reference base station can thereby obtain the time difference and time. The difference is compared with a predetermined time difference, and when the time difference is greater than or equal to the predetermined time difference, the alarm information is reported.

In another embodiment, the method further includes: when the reference base station is a base station that cannot receive GNSS grant and/or 1588V2 grant (ie, a base station that only receives NTP grant, and/or SNTP grant, and/or 1588V2 ATR grant), And when the eMBMS service and the like need to have the base station having the accurate absolute time, the base station to be synchronized receives the extended buffer message sent by the coordinated device, and the expanded cache message is used to indicate that the base station to be synchronized expands the FIFO of the base station to be synchronized (First Input First Output, first entry) First out queue). Correspondingly, after the base station to be synchronized receives the extended buffer message, the FIFO is changed from a normal state to an expanded state, so as to cope with the time deviation existing between the BMSC device and the base station to be synchronized. When the base station to be synchronized completes the traffic transmission with the BMSC device, the FIFO transitions from the expanded state to the normal state.

Wherein, the mode indicates that the reference base station is not the base station receiving the GNSS grant or receiving the 1588V2 grant time. At this time, strict frame number and frame timing synchronization between the reference base station and the base station to be synchronized in the same synchronization packet can be achieved, and strict time synchronization with each other can be achieved, but only the base station time and standard GPS time in the area. There is a fixed deviation. In this case, when encountering a service (such as eMBMS) that requires the base station to have an accurate absolute time, it is necessary to expand the FIFO of the base station. The effect of this bias is absorbed by expanding the FIFO (eg, enabling synchronization with eMBMS between BMSC devices).

Further, after the base station to be synchronized completes the reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation, the to-be-synchronized base station performs transmission of the broadcast multicast service with the broadcast multicast service center BMSC device.

It is worth noting that after the base station to be synchronized completes the reference time synchronization with the reference base station, the surface base stations (between the reference base station and the base station to be synchronized) are strictly reference time synchronized. When the reference base station is a base station receiving GNSS grant or 1588V2 timing (using an accurate absolute time), when performing a service (such as eMBMS) requiring time synchronization of the service content, the BMSC device and the base station (including the reference base station and the to-be-synchronized) The time synchronization of the business content can be realized between the base stations. When the reference base station is a base station that cannot receive the GNSS grant and the 1588V2 grant time (which can be regarded as using an inaccurate absolute time), when performing a service (such as eMBMS) requiring time synchronization of the service content, the base station (including the base station and the base station and The base station to be synchronized needs to expand the FIFO to achieve time synchronization of the service content with the BMSC device.

It will be clearly understood by those skilled in the art that for the convenience and brevity of the description, only the division of each functional module described above is exemplified. In practical applications, the above function assignment can be completed by different functional modules as needed. The internal structure of the device is divided into different functional modules to perform all or part of the functions described above. For the specific working process of the system, the device and the unit described above, reference may be made to the corresponding process in the foregoing method embodiments, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be used. Combinations can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product stored in a storage medium. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) or a processor to perform all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Claims

A synchronization device, wherein the device is applied to a base station to be synchronized, the base station to be synchronized is a base station that synchronizes frame number synchronization and frame timing with a reference base station, and the reference base station provides to the base station to be synchronized The base station of the reference time, the reference frame number, and the reference frame timing, the device includes:

Obtaining a module, configured to obtain a first frame number and a first frame timing, and provide the first frame number and the first frame timing to a computing module, where the first frame number is the to-be-synchronized base station and the a frame number after the reference frame number is synchronized, where the first frame timing is a frame timing after the base station to be synchronized is synchronized with the reference frame timing;

An obtaining module, configured to acquire time information by using a first timing device, and provide the time information to the obtaining module, where the first timing device is configured to provide time information to the device;

The obtaining module is further configured to obtain a second frame number and a second frame timing according to the time information, and provide the second frame number and the second frame timing to the computing module;

The calculating module is configured to obtain a frame number deviation by using the first frame number and the second frame number; and obtain a frame timing deviation by using the first frame timing and the second frame timing, and The frame number deviation and the frame timing deviation are provided to the synchronization module;

The synchronization module is configured to complete a reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation.
The synchronizing apparatus according to claim 1, wherein when the time information includes a Coordinated Universal Time UTC time, the obtaining module comprises:

An obtaining unit, configured to acquire a UTC time provided by the timing device, and provide the UTC time to the conversion unit;

The converting unit is configured to convert the UTC time into a global positioning system GPS time in combination with the leap second information; convert the GPS time into the second frame number and the second frame timing.
Synchronization apparatus according to claim 1 or 2, wherein said synchronization module, package include:

a converting unit, configured to convert the frame number deviation and a frame timing deviation into a time difference value, and provide the time difference value to a calibration unit;

The calibration unit is configured to calibrate the time information by using the time difference to complete absolute time synchronization with the reference base station.
The synchronization device according to claim 3, wherein the device further comprises:

The first receiving module is configured to receive the alarm information sent by the reference base station, where the alarm information is used to indicate that the time difference is greater than or equal to a predetermined time difference.
A synchronizing apparatus according to any one of claims 1 to 4, characterized in that

The synchronization module is further configured to synchronize the device to the first reference source to complete frequency synchronization with the reference base station, where the first reference source is the same as the reference source synchronized with the reference base station.
A synchronizing apparatus according to any one of claims 1 to 4, characterized in that

The synchronization module is further configured to synchronize the device to a second reference source to determine a frequency offset between the device and the reference base station, where the second reference source is different from a reference source synchronized with the reference base station When the frequency deviation is less than the predetermined frequency deviation, synchronization with the second reference source continues.
The synchronization device according to any one of claims 1 to 6, wherein the reference time of the reference base station is the time provided by the GNSS GNSS timing, or the time provided by the second edition 15881588V2 timing, or time The time provided by the information protocol NTP grant, or the time provided by the simple time information protocol SNTP grant, or the time provided by the second version 1588 adaptive clock recovery 1588V2ATR grant.
The synchronization device according to claim 7, wherein the device further comprises:

a second receiving module, configured to receive an extended buffer when a reference time of the reference base station is a time provided by a time information protocol NTP grant, or a time provided by a simple time information protocol SNTP grant, or a time provided by a base station of a 1588 V2 ATR grant Message, the expanded cache message The first-in first-out queue FIFO for indicating that the base station to be synchronized expands the base station to be synchronized.
A synchronizing device according to claim 4, wherein

The synchronization module is further configured to perform absolute time synchronization with the candidate base station, where the candidate base station is a base station that replaces the failed base station, wherein the device and the candidate reference are The manner in which the base station performs absolute time synchronization is the same as the manner in which the apparatus performs absolute time synchronization with the reference base station.
The synchronization device according to claim 9, wherein the device further comprises:

An execution module, configured to perform transmission of a broadcast multicast service with a broadcast multicast service center BMSC device.
A synchronization device, wherein the device is applied to a base station to be synchronized, the base station to be synchronized is a base station that synchronizes frame number synchronization and frame timing with a reference base station, and the reference base station provides to the base station to be synchronized The base station of the reference time, the reference frame number, and the reference frame timing, the device includes:

a memory for storing information including program instructions;

a processor, coupled to the memory, for controlling execution of the program instruction, specifically for obtaining a first frame number and a first frame timing, where the first frame number is the to-be-synchronized base station and the reference frame a frame number after synchronization, the first frame timing is a frame timing after the base station to be synchronized is synchronized with the reference frame timing; obtaining time information by the first timing device, and obtaining a second frame number according to the time information And a second frame timing; obtaining a frame number deviation by using the first frame number and the second frame number; and obtaining a frame timing deviation by using the first frame timing and the second frame timing; according to the frame The number deviation and the frame timing deviation are synchronized with the reference time of the reference base station.
The synchronization device according to claim 11, wherein when the time information includes a Coordinated Universal Time UTC time, the processor is further configured to acquire a UTC time provided by the timing device; Translating the UTC time into a global positioning system GPS time; converting the GPS time into the second frame number and the second frame timing.
A synchronizing device according to claim 11 or 12, characterized in that

The processor is further configured to convert the frame number deviation and the frame timing deviation into a time difference value; and the time information is calibrated by the time difference to complete absolute time synchronization with the reference base station.
The synchronization device according to claim 13, wherein the device further comprises: a receiver;

The receiver is configured to receive the alarm information sent by the reference base station, where the alarm information is used to indicate that the time difference is greater than or equal to a predetermined time difference.
A synchronizing device according to any one of claims 11-14, characterized in that

The processor is further configured to synchronize the device to the first reference source to complete frequency synchronization with the reference base station, where the first reference source is the same as the reference source synchronized with the reference base station.
A synchronizing device according to any one of claims 11-14, characterized in that

The processor is further configured to synchronize the device with a second reference source to determine a frequency offset between the device and the reference base station, where the second reference source is different from a reference source synchronized with the reference base station When the frequency deviation is less than the predetermined frequency deviation, synchronization with the second reference source continues.
The synchronization device according to any one of claims 11-16, wherein the reference time of the reference base station is the time provided by the GNSS GNSS grant, or the time provided by the second edition 15881588V2 timing, or time The time provided by the information protocol NTP grant, or the time provided by the simple time information protocol SNTP grant, or the time provided by the second version 1588 adaptive clock recovery 1588V2ATR grant.
The synchronization device according to claim 14, wherein the device further comprises:

The receiver is further configured to: when the reference time of the reference base station is the time provided by the time information protocol NTP grant, or the time provided by the simple time information protocol SNTP grant, or the time provided by the base station of the 1588V2 ATR grant, the receiving extension The cached message is used to indicate that the to-be-synchronized base station expands the first-in first-out queue FIFO of the to-be-synchronized base station.
The synchronizing device according to claim 14, wherein

The processor is further configured to perform absolute time synchronization with the candidate base station, where the candidate base station is a base station that replaces the failed base station, wherein the device and the candidate reference are The manner in which the base station performs absolute time synchronization is the same as the manner in which the apparatus performs absolute time synchronization with the reference base station.
A synchronizing device according to claim 19, wherein

The processor is further configured to perform transmission of a broadcast multicast service with a broadcast multicast service center BMSC device.
A synchronization method, the method is applied to a base station to be synchronized, the base station to be synchronized is a base station that synchronizes with a frame number of a reference base station and frame timing, and the reference base station provides the base station to be synchronized Base station for reference time, reference frame number, and reference frame timing, the method includes:

The base station to be synchronized obtains a first frame number and a first frame timing, where the first frame number is a frame number after the base station to be synchronized is synchronized with the reference frame number, and the first frame timing is the a frame timing after the synchronization base station synchronizes with the reference frame timing;

The base station to be synchronized acquires time information by using the first timing device, and obtains a second frame number and a second frame timing according to the time information;

The base station to be synchronized obtains a frame number deviation by using the first frame number and the second frame number; and obtains a frame timing deviation by using the first frame timing and the second frame timing;

The base station to be synchronized completes synchronization with the reference time of the reference base station according to the frame number deviation and the frame timing deviation.
The synchronization method according to claim 21, wherein when the time information includes a Coordinated Universal Time UTC time, the to-be-synchronized base station acquires time information by using a first timing device, and obtains a second frame according to the time information. Number and second frame timing, including:

The base station to be synchronized acquires a UTC time provided by the timing device;

Converting the UTC time into a global positioning system GPS time in combination with leap second information;

Converting the GPS time to the second frame number and the second frame timing.
The synchronization method according to claim 21 or 22, wherein the base station to be synchronized completes the reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation, and includes:

The base station to be synchronized converts the frame number deviation and the frame timing deviation into a time difference value;

The base station to be synchronized performs calibration on the time information by using the time difference to complete absolute time synchronization with the reference base station.
The synchronization method according to claim 23, wherein after the base station to be synchronized converts the frame number deviation and the frame timing deviation into a time difference value, the method further includes:

The base station to be synchronized receives the alarm information sent by the reference base station, and the alarm information is used to indicate that the time difference is greater than or equal to a predetermined time difference.
The synchronization method according to any one of claims 21 to 24, wherein before the obtaining, by the base station to be synchronized, the first frame number and the first frame timing, the method further comprises:

The base station to be synchronized is synchronized with the first reference source to complete frequency synchronization with the reference base station, and the first reference source is the same as the reference source synchronized with the reference base station.
The synchronization method according to any one of claims 21 to 24, wherein before the obtaining, by the base station to be synchronized, the first frame number and the first frame timing, the method further comprises:

The base station to be synchronized is synchronized with the second reference source to determine a frequency offset between the base station to be synchronized and the reference base station, and the second reference source is different from the reference source synchronized by the reference base station;

When the frequency deviation is less than a predetermined frequency deviation, the to-be-synchronized base station continues to synchronize with the second reference source.
The synchronization method according to any one of claims 21 to 26, wherein the reference time of the reference base station is the time provided by the Global Navigation Satellite System (GNSS) GNSS, or the second version 1588 The time provided by the 1588V2 grant, or the time provided by the time information protocol NTP grant, or the time provided by the simple time information protocol SNTP grant, or the time provided by the second edition 1588 adaptive clock recovery 1588V2ATR grant.
The synchronization method according to claim 27, wherein the reference time of the reference base station is a time provided by a time information protocol NTP grant, or a time provided by a simple time information protocol SNTP grant, or a base station provided by a 1588 V2 ATR grant At the time of the method, the method further includes:

The base station to be synchronized receives the extended cache message, and the extended cache message is used to indicate that the base station to be synchronized expands the first-in first-out queue FIFO of the base station to be synchronized.
The synchronization method according to claim 24, wherein said communication system further comprises an alternative reference base station, said candidate base station being a base station replacing said failed base station; receiving at said base station to be synchronized After the alarm information sent by the reference base station, the method further includes:

The base station to be synchronized performs absolute time synchronization with the candidate base station, wherein the method in which the base station to be synchronized and the candidate base station perform absolute time synchronization and the base station to be synchronized and the base station perform absolute time The way to synchronize is the same.
The synchronization method according to any one of claims 21 to 29, wherein after the base station to be synchronized completes the reference time synchronization with the reference base station according to the frame number deviation and the frame timing deviation The method further includes:

The base station to be synchronized performs transmission of a broadcast multicast service with a broadcast multicast service center BMSC device.