WO2010054546A1

WO2010054546A1 - Synchronization method, base station, network server and communication system

Info

Publication number: WO2010054546A1
Application number: PCT/CN2009/071621
Authority: WO
Inventors: 刘洪�; 黄晖; 林海鸿; 吴勇; 江胜峰; 伊成刚
Original assignee: 深圳华为通信技术有限公司
Priority date: 2008-11-12
Filing date: 2009-05-04
Publication date: 2010-05-20
Also published as: CN101420747B; CN101420747A

Abstract

A synchronization method, a base station, a network server and a communication system. The method involves receiving a preamble signal from a clock reference base station by a clock slave base station, detecting the preamble signal and determining a phase offset to the clock reference base station, determining a frequency offset to the clock reference base station according to the phase offset, and performing time synchronization using the determined phase offset, performing frequency synchronization using the frequency offset so as to realize the synchronization with the clock reference base station.

Description

SYNCHRONIZATION METHOD, BASE STATION, NETWORK SERVER, AND COMMUNICATION SYSTEM [0001] This application claims priority to the Chinese application filed on Nov. 12, 2008, with the application number 200810217432.2, entitled "Synchronization Method, Base Station, Network Server, and Communication System", The entire contents of this application are incorporated herein by reference.

Technical field

The present invention relates to communication technologies, and more particularly to a method of synchronization, a base station, a network server, and a communication system.

Background technique

In the existing wireless communication system, the base station's synchronous multi-application GPS (Global Position System) synchronization technology is used for synchronization, and the existing global positioning system GPS is divided into:

Space part - GPS satellite constellation;

Ground control part - ground monitoring system;

User equipment part - GPS signal receiver.

The GPS satellite constellation works in conjunction with the ground monitoring system to provide an accurate time signal to the ground that covers all areas of the world. The GPS signal receiver outputs a precise 1PPS (Pulse Per Second) after receiving the time signal of the satellite constellation. Second pulse) Pulse and absolute time to communication devices (such as base stations, etc.) that need to be synchronized. Accurate absolute time and precise, stable 1PPS pulses are important conditions for synchronization within a communication system.

In the above process, the inventors found that at least the following problems exist in the prior art: In the indoor coverage scenario, the traditional synchronization mechanism such as the GPS synchronization technology cannot solve the synchronization problem well, such as the GPS signal transmitted through the satellite, in the building. In indoors where objects are blocked, and in densely populated urban areas, GPS signals are blocked and attenuated, resulting in GPS signals not being able to receive well, so that communication devices installed indoors and requiring synchronization cannot pass through the GPS receiver directly. Achieve good synchronization. Outdoor GPS in the case of lightning strikes, it is easy to cause GPS failure, resulting in strong interference with other base stations, and GPS also leads to increased costs.

Summary of the invention The embodiment of the invention provides a synchronization method, a base station, a network server and a communication system, so as to solve the problem that the base station cannot receive the GPS signal and cannot be synchronized.

A method for synchronizing provided by the embodiment of the present invention specifically includes:

The clock receives a preamble signal from the base station from the clock reference base station;

Detecting the preamble signal to determine a phase deviation from the clock reference base station;

Determining a frequency deviation from the clock reference base station according to the phase deviation;

Time synchronization is performed using the determined phase deviation, and frequency synchronization is performed using the frequency deviation.

A base station includes: a receiving module, a detecting module, and a synchronization module, where the receiving module is configured to receive a preamble signal from a clock reference base station, and forward the preamble signal to the detecting module;

The detecting module is configured to detect the preamble signal, determine a phase deviation from the clock reference base station, and determine a frequency deviation from the clock reference base station according to the phase deviation;

The synchronization module is configured to perform time synchronization according to the determined phase deviation, and perform frequency synchronization according to the frequency deviation.

A network server provided by the embodiment of the present invention specifically includes a receiving module, a confirming module, a storage module, a selecting module, and a sending module.

The receiving module is configured to receive a preamble signal set S 1 from a base station;

The acknowledgment module is configured to confirm the base station to which each preamble signal in the set S 1 belongs, and form a base station set S2;

The storage module is configured to store a clock state of the base station;

The selecting module is configured to select a clock reference base station from the base station set S2 confirmed by the confirming module according to a clock state of the base station stored by the storage module, and send related information of the selected clock reference base station to the Sending module

The sending module is configured to send related information of the clock reference base station to the base station. The communication system provided by the embodiment of the present invention includes a clock slave base station, and the clock is connected to the clock reference base station in a communicable manner from the base station; The clock slave base station is configured to receive a preamble signal from a clock reference base station, detect the preamble signal, determine a phase deviation from the clock reference base station, and determine a frequency offset from the clock reference base station according to the phase deviation, Time synchronization is performed using the determined phase deviation, and frequency synchronization is performed using the frequency deviation.

In this way, the clock slave base station can quickly synchronize with the clock reference base station according to the preamble signal of the clock reference base station, and does not need to receive the GPS signal, so that the base station can be free from the limitation of the coverage scenario, and Since the base station cannot receive the GPS signal and cannot be synchronized, the base station can acquire the synchronization simply and quickly by the embodiment of the present invention, and the cost of the base station can be reduced because the GPS device can be eliminated.

DRAWINGS

FIG. 1 is a schematic diagram of synchronization according to an embodiment of the present invention;

2 is a schematic flowchart of an initial synchronization phase according to an embodiment of the present invention;

FIG. 3 is a schematic flowchart of a cycle synchronization phase according to an embodiment of the present disclosure;

FIG. 4 is a schematic flowchart of a method for determining a clock reference base station according to an embodiment of the present invention; FIG. 5 is a schematic flowchart of a method for re-determining a clock reference base station according to an embodiment of the present invention; FIG. A schematic diagram of a method for determining a clock reference base station;

FIG. 7 is a schematic structural diagram of a base station according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of a network server according to an embodiment of the present invention.

detailed description

The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the specific embodiments and the accompanying drawings.

In a WiMAX system, the pilot signal may be a Preamble signal, and embodiments of the present invention are not limited to WiMAX systems.

In the WiMAX system, the base station's Preamble signal coverage distance is much higher than its broadcast message and the traffic channel coverage distance. With this feature, in the embodiment of the present invention, the base station that needs to be synchronized can Receiving a Preamble signal of a neighboring base station and recovering the clock of the neighboring base station by demodulating the Preamble signal of the neighboring base station, thereby achieving synchronization with the neighboring base station.

With the synchronization method provided by the embodiment of the present invention, in the network area, the clock reference base station R-BS is set, and the base station capable of receiving the GPS signal or obtaining the precise synchronization by other methods can be selected as the clock reference base station. The other base station capable of receiving the Preamble signal of the clock reference base station R-BS can be used as the clock slave base station SLAVE-BS, as shown in FIG. The clock receives the Preamble signal of the clock reference base station R-BS in the local area from the base station SLAVE-BS, and measures the phase deviation of the local clock from the base station SLAVE-BS relative to the clock reference base station R-BS, and then according to the measurement The phase deviation is adjusted for the time of the clock from the base station SLAVE-BS, and further, the frequency deviation is obtained according to the measured phase deviation, and the frequency of the clock from the base station SLAVE-BS is adjusted according to the frequency deviation, thereby realizing The clock is synchronized from the frequency and time between the base station SLAVE-BS and the clock reference base station R-BS.

Thus, by the above synchronization method, the clock slave base station SLAVE-BS can quickly synchronize with the clock reference base station R-BS according to the Preamble signal of the clock reference base station, without receiving a GPS signal, so that it can be The coverage of the scene is not synchronized because the base station cannot receive the GPS signal. According to the embodiment of the present invention, the base station can acquire synchronization simply and quickly, and the cost of the base station can be reduced because the GPS device can be eliminated.

Preferably, in the embodiment of the present invention, the synchronization of the clock from the base station SLAVE-BS can be performed in two stages, that is, the initial synchronization phase and the periodic synchronization phase, and the initial synchronization in the synchronization method provided by the embodiment of the present invention as shown in FIG. The schematic diagram of the process of the phase is as follows:

Step 200: Determine to monitor the start frame of the clock reference base station R-BS, and the number of repetitions N of the interception.

In the embodiment of the present invention, if a certain clock needs to be synchronized from the base station SLAVE-BS, after the clock reference base station R-BS is determined, the predetermined clock reference base station R-BS Preamble signal can be used for synchronization.

After determining the clock reference base station R_BS, the clock is determined from the base station SLAVE-BS to synchronize the start frame of the clock reference base station R-BS, such as the frame determining the start frame to be monitored. In the embodiment of the present invention, the determining the starting frame to be monitored may be: randomly selecting a frame of the clock reference base station R-BS as a starting frame; preferably, the base station may be referenced according to the clock. The start time of the R_BS and the synchronization period to determine the starting frame to be monitored, so as to ensure that the clock can be monitored from the base station to the signal of the clock reference base station; further determining the number of repetitions of the monitoring N, here , N>=1. If the value of N can be 100 or 200, it can even be 1.

Step 201: Receive a Preamble signal of the clock reference base station R_BS from the determined start frame, measure a phase deviation from the Preamble signal, determine a frequency offset according to the phase deviation, and perform a synchronization operation.

In this embodiment, the clock from the base station SLAVE-BS starts measuring the phase deviation from the Preamble signal for each received Preamble signal from the determined start frame, and repeats the N times. Then, the phase deviations obtained by the N measurements are averaged to obtain an average phase deviation, and the frequency deviations are determined according to the phase deviations obtained by the N measurements, and averaged to obtain an average frequency deviation. The local time is adjusted using the average phase deviation, and the local frequency is adjusted based on the average frequency deviation, so as to achieve synchronization with the time and frequency of the clock reference base station.

The determining the frequency deviation based on the phase deviation obtained by the N measurements may specifically be to calculate the frequency deviation according to the following formula:

Equation 1: Frequency deviation = ( Pi - Pj ) / ( Ti - Tj )

The Pi is the phase deviation detected by the ith time, Ti is the time when the phase deviation is detected for the ith time, the Pj is the phase deviation detected by the jth time, and Tj is the time of detecting the phase deviation of the jth time, i> j. Further, in this embodiment, the value of i<=N, j<=N.

For example, in this embodiment, the corresponding frequency deviation may be determined for two consecutive phase deviations, that is, ij is 1 at this time, so that N-1 frequency deviations may be obtained, and the N-1 frequency deviations are described. Find the average and get the average frequency deviation.

In this way, through the initial synchronization process, the clock slave base station SLAVE-BS can quickly synchronize with the clock reference base station R-BS according to the Preamble signal of the clock reference base station, without receiving a GPS signal, so that Limited by the coverage scenario, not because the base station cannot Receiving the GPS signal results in the inability to synchronize. With the embodiment of the present invention, the base station can acquire synchronization simply and quickly, and because the GPS device can be eliminated, the cost of the base station can be reduced.

After the clock is synchronized from the base station, the normal operation is started. Further, in the subsequent process, the clock slave base station SLAVE-BS can also use the periodic synchronization method provided by the embodiment of the present invention. As shown in FIG. 3, it is a schematic flowchart of a cycle synchronization phase in a base station synchronization method according to an embodiment of the present invention, which is specifically as follows:

Step 300: Determine a synchronization period.

In this embodiment, when the synchronization precision reaches a higher level, the cycle synchronization phase may be entered, and the synchronization period may be determined according to the currently obtained synchronization situation, such as 50s or 100s, etc., so that when the synchronization period expires , for a sync.

Step 301: When the synchronization period is reached, receive a Preamble signal from the clock reference base station R-BS, measure a phase deviation from the Preamble signal, determine a frequency offset according to the phase deviation, and perform a synchronization operation.

In this embodiment, the local time is adjusted by using the phase deviation, and further, according to the frequency deviation, the local frequency is adjusted according to the determined frequency deviation, so as to achieve the time and frequency of the same clock reference base station. Synchronize. Determining the frequency deviation of the clock reference base station R-BS according to the phase deviation may be determining the frequency deviation according to the method of Equation 1 above, and then taking the value of Pi to detect the phase deviation of the current detection, and Pj is the last synchronization. The phase deviation detected by the period, Ti - Tj is the synchronization period.

Preferably, in the embodiment of the present invention, the synchronization period can be gradually increased according to the synchronization precision, that is, the synchronization period can be set to be larger as the synchronization precision is higher, and the synchronization period can be no longer increased when the synchronization period is increased to 1000s. If the phase deviation of the same clock reference base station R-BS is less than the preset threshold t (such as 2us), it can be judged that the clock has entered the steady state from the base station SLAVE-BS.

Optionally, in the embodiment of the present invention, the phase synchronization phase may be directly entered, and the initial synchronization is not required.

Preferably, in the embodiment of the present invention, the clock slave base station SLAVE-BS and the clock reference base station R-BS The clock reference relationship between the two can be transmitted. For example, if there are four base stations BS0, BS1, BS2, and BS3 in the system, BS1 uses BS0 as the clock reference base station, BS2 can use BS1 as the clock reference base station, and BS3 can use BS2 as the base station. The clock reference base station, of course, the BS3 may also refer to the base station by using BS0 or BS1 as a clock, so that even one base station in the entire network may be connected to a GPS or other standard clock source, and other base stations directly or indirectly use it as Reference source to achieve synchronization of the entire network.

In the network, the base station maintains its own clock state and reports it to the network server. The network server saves the clock state of the base station and the neighbor relationship in the network. A method for determining a clock state according to an embodiment of the present invention is: a base station that obtains synchronization by using an external GPS or other standard clock source, and has a clock state of 0; and a base station with a base station of 0 as a reference base station of the base station is level 1 The level 1 base station is used as the clock reference base station, which is level 2, and is transmitted downwards in turn. Level 0 is the highest priority. The larger the number of stages, the lower the priority. When a certain base station needs to be synchronized, a method for determining a clock reference base station according to the embodiment of the present invention may be adopted, as shown in FIG. 4:

Step 400: The network server receives the Preamble signal set reported from the base station from a certain clock.

Sl.

In the embodiment of the present invention, when a certain clock needs to be synchronized from the base station BS1, the clock from the base station BS1 can scan the Preamble signal of the neighboring base station, and report the scanned Preamble signal of the neighboring base station to the network server as the set S1. Preferably, the clock from the base station BS1 can report a stronger signal in the Preamble signal of the neighboring base station to the network server. For example, it may be a threshold value T1 of a preset signal strength RSSI (Received Signal Strength Indication), and if the signal strength RSSI of the Preamble signal of the neighboring base station is greater than the T1, The Preamble signal is placed in the set S1; or the threshold T2 of the carrier-to-interference noise ratio (CINR) is preset, if the neighboring base station is described If the CINR of the Preamble signal is greater than the T2, the Preamble signal is placed in the set S1; or when the signal strength RSSI of the Preamble signal of the neighboring base station is greater than the T1 and the CINR is greater than When T2 is described, the Preamble signal is placed in the set S1, and the clock reports the set S1 from the base station BS1 to the network. Network server.

In the embodiment of the present invention, the network server may be an independent physical entity in the system, or may be another entity integrated in the network, such as a network management system integrated in the network, or integrated in the network. In the gateway. In this embodiment, the network server stores a clock state of a base station in the network and a list of neighboring base stations of each base station.

Step 401: The network server confirms that the base stations to which each Preamble signal in the set S1 belongs, and form a base station set S2.

Step 402: The network server selects a clock reference base station R-BS from the base station set S2.

In the embodiment of the present invention, the network server queries each base station in the base station set S2 to query its clock state, and selects a base station with a higher priority clock state as the clock reference base station R-BS. Preferably, the base station that can select the highest priority clock state is used as the clock reference base station. Further, if a plurality of Preamble signals in the set S1 belong to the selected clock reference base station, preferably, the Preamble signal with the highest signal quality is selected, such as the RSSI maximum or the CINR maximum.

Step 403: Notify the clock slave base station of the confirmed clock reference base station information. In this embodiment, the related information of the clock reference base station includes a clock state of the clock reference base station, a Preamble signal sequence number, and a frequency point of the clock reference base station. Further, the related information may further include the clock. Refer to the start time of the base station and its synchronization period.

In this way, after receiving the relevant information of the clock reference base station notified by the network server from the base station BS1, the clock confirms the Preamble signal of the clock reference base station to be received according to the Preamble signal sequence number and the frequency point of the determined clock reference base station; Preferably, the received start frame is determined according to the start time of the clock reference base station and its synchronization period, and the Preamble signal from the clock reference base station is received from the determined start frame, according to the foregoing The synchronization method provided by the embodiment of the invention performs synchronization.

Optionally, in the embodiment of the present invention, if the network server cannot confirm the base station to which each Preamble signal in the set S1 belongs, the signal quality can be confirmed according to the frequency self-planning. The Preamble signal transmits information of the confirmed Preamble signal to the clock slave base station. In this embodiment, if the network server finds that it is unable to confirm the base station to which each Preamble signal belongs in the set S1, it may determine, according to the result of the frequency self-planning, whether each Preamble signal in the set S1 has the same The preamble signal of the same frequency of the base station, if any, preferably, selecting the Preamble signal with the highest signal quality from the preamble signals of the same frequency for the base station to serve as a clock reference; if not, selecting from the set S 1 The Preamble signal with the highest signal quality is selected for use by the base station as a clock reference.

The base station can determine the appropriate clock reference base station for the base station to enable the base station to use the clock reference base station for synchronization, and select the clock reference base station with the highest clock priority or the highest priority when determining the clock reference base station, so that Effectively avoiding the situation that multiple base stations form a clock reference closed loop, which ensures the mid-synchronization performance of the base stations in the network.

Further, when the base station BS1 is in the process of measuring the Preamble signal for synchronization, if a clock source is lost, the clock reference base station needs to be re-confirmed, and the base station may rescan the Preamble signal of its neighboring base station and report it. The network server may re-confirm the clock reference base station and perform synchronization according to the scheme of the above embodiment. The clock reference base station may be re-confirmed according to the method provided by the embodiment of the present invention, as shown in FIG. 5:

Step 500: If the clock source of the base station is lost, report the network server.

When the base station loses its clock source during the synchronization process, such as the clock reference base station cannot be locked, the base station reports the information whose clock source is lost to the network server.

Step 501: The network server selects a new clock reference base station from the Preamble signal set reported by the base station, and instructs the base station to scan the new clock reference base station.

In this embodiment, the network server may directly select a new clock reference base station from the Preamble signal set S1 reported by the previous base station, where the base station may be instructed to select a new clock reference base station according to the method provided in the foregoing embodiment. After selecting a new clock reference base station, the network server instructs the base station to scan the selected new clock reference base station.

Step 502: After receiving the indication from the network server, the base station scans the new clock reference base station, and reports the scan result to the network server. In this embodiment, the Preamble signal of the clock reference base station is scanned, and the signal strength is measured, and the scanned result is reported to the network server.

Step 503: The network server determines, according to the scan result reported by the base station, whether the new clock reference base station can be scanned. If yes, go to step 504, otherwise go back to step 501.

In this embodiment, after receiving the scan report reported by the base station, the network server determines, according to the scan report, whether the base station can scan the new clock reference base station, and if yes, the base station can Synchronization is performed using the clock reference base station, if not, then returning to step 501, re-selecting a new clock reference base station for the base station until a suitable clock reference base station is selected for the base station.

Step 504: The network server notifies the base station of related information of the new clock reference base station, and instructs the base station to perform synchronization by using the new clock reference base station.

When the network server confirms that the base station can use the new clock reference base station according to the scan report of the base station, notify the base station of the related information of the new clock reference base station, and instruct the base station to utilize the new clock reference. The base station synchronizes. Here, the related information includes a clock state of the clock reference base station, a Preamble signal sequence number, and a frequency point of the clock reference base station. Further, the related information may further include a start time of the clock reference base station and Its synchronization period. The base station is synchronized.

Preferably, the clock state of the base station BS2 changes during the operation of the network. Preferably, if the neighboring base station of the base station BS2 has a neighboring base station capable of receiving the Preamble signal of the base station BS2 and is currently synchronizing, Then, the neighboring base stations re-select the clock reference base station. Specifically, the method provided by the embodiment of the present invention may be used, as shown in FIG. 6:

Step 600: If the clock state of a base station changes, send a message to notify the network server. In this embodiment, when the clock state of a certain base station BS2 changes, if the clock state priority of the base station BS2 increases or decreases, or the clock state thereof changes from an unstable state to a stable state, the base station BS2 sets its own clock. The status change message informs the web server. Step 601: The network server records a current clock state of the base station.

Step 602: The network server determines whether there is a neighboring base station that needs to be synchronized in the neighboring base station of the base station, and if not, ends the process; if yes, the process goes to step 603.

Step 603: The network server determines a neighboring base station that needs to be synchronized, and combines the neighboring base stations that need to be synchronized into a set S3, and updates a clock source candidate list of each neighboring base station in the set S3.

In this embodiment, the network server may separately maintain a clock source candidate list for each base station, where the related information that can be used as the clock reference base station of the base station is recorded, and when the clock state of the base station BS2 changes, The network server updates the clock state information about the base station BS2 in the list of clock source candidates of its neighboring base stations.

Step 604: The network server reselects a new clock reference base station for each neighboring base station in the set S3.

Here, the method provided by the embodiment of the present invention may be used to reselect a new clock reference base station for each neighboring base station in the set S3.

Step 605: Determine whether the newly selected clock reference base station is the same as the clock reference base station selected last time for the base station. If they are the same, the process ends. If they are not the same, then go to step 606.

Step 606: Instruct the neighboring base station to scan the newly selected clock reference base station and report the scan report.

When the network server finds that the newly selected clock reference base station is different from the last time reference base station selected for the neighbor base station, the message is sent to the neighboring base station to scan the newly selected clock reference base station and report the scan report.

After receiving the message, the neighboring base station scans the newly selected clock reference base station and reports a scan report to the network server.

Step 607: The network server determines, according to the scan report, whether the new clock reference base station can be scanned. If no, the process ends; if yes, go to step 608.

Step 608: The network server instructs the neighboring base station to perform synchronization by using the new clock reference base station.

Through the above method, when the clock state of an alternative clock reference station changes, the network service The trigger triggers the completion of the clock reference base station reselection.

The embodiment of the present invention further provides a base station. As shown in FIG. 7, the base station includes a receiving module 700, a detecting module 702, and a synchronization module 704. The receiving module 700 is configured to receive a Preamble signal from a clock reference base station, and The Preamble signal is forwarded to the detection module 702. The detection module 702 is configured to detect the Preamble signal, determine a phase deviation from the clock reference base station, and determine a frequency with the clock reference base station according to the phase deviation. The synchronization module 704 is configured to perform time synchronization according to the phase deviation, and perform frequency synchronization according to the frequency deviation.

In the embodiment of the present invention, the detecting module 702 may perform the frequency deviation from the clock reference base station according to the phase deviation according to the above formula 1.

Further, in the embodiment of the present invention, the synchronization module 704 further includes a digital-to-analog conversion module DA7040 and a oven controlled crystal oscillator (OCXO7042), and the synchronization module 704 performs the phase deviation and the frequency deviation according to the phase deviation and the frequency deviation. The OCXO 7042 is configured to adjust a local time according to the phase deviation; the DA 7040 converts the phase deviation to output a voltage control voltage, and the OCXO 7042 is configured to adjust a local according to the voltage control voltage. Frequency, which is synchronized by adjusting the local time and frequency.

Alternatively, the DA 7040 converts the phase deviation and the frequency deviation, and outputs a voltage control voltage, and the OCXO 7042 is configured to adjust the local frequency and the local time according to the voltage control voltage, so as to achieve adjustment by adjusting the local time and frequency. Synchronize.

The embodiment of the present invention further provides a network server. As shown in FIG. 8, the network server includes a receiving module 800, an acknowledgment module 802, a storage module 804, a selection module 806, and a sending module 808.

The receiving module 800 is configured to receive a Preamble signal set S1 from a base station. The confirmation module 802 is configured to confirm the base station to which each Preamble signal in the set S1 belongs, and form a base station set S2. The storage module 804 is configured to store a clock state of the base station. Preferably, the start time and the synchronization period of the base station are also stored. The selection module 806 is configured to select a clock reference base station from the base station set S2 confirmed by the confirmation module 802 according to the information stored by the storage module 804, and send related information of the selected clock reference base station to the sending module 808. Specifically, the present invention In an embodiment, the selecting module 806 queries the storage module 804 for the clock state of each base station in the base station set S2, and selects a base station with a higher priority clock state as the clock reference base station R-BS; preferably, The base station that can select the highest priority clock state is used as the clock reference base station. Further, if a plurality of Preamble signals in the set S1 belong to the selected clock reference base station, preferably, the Preamble with the highest signal quality is selected. The signal may be the RSSI maximum or the CINR maximum, and the like. In this embodiment, the related information of the clock reference base station includes a clock state of the clock reference base station, a Preamble signal sequence number, and a frequency point of the clock reference base station; The related information may further include a start time of the clock reference base station and a synchronization period thereof. The sending module 808 is configured to send related information of the clock reference base station to the base station.

After receiving the information about the clock reference base station notified by the network server, the base station confirms the Preamble signal of the clock reference base station to be received according to the determined clock reference sequence number of the base station and the frequency point; The received start frame may also be determined according to the start time of the clock reference base station and its synchronization period, and the Preamble signal from the clock reference base station is received from the determined start frame, according to the present invention. The synchronization method provided by the embodiment performs synchronization.

Further, in the embodiment of the present invention, the confirmation module 802 is further configured to: if the base station of each Preamble signal in the set S1 cannot be confirmed, send the set S1 to the selection module 806, the selection module The 806 is further configured to: modulate the Preamble signal with the best signal quality according to the frequency, and send the information of the confirmed Preamble signal to the sending module 808, where the sending module 808 is further configured to send the information of the confirmed Preamble signal. To the base station.

Further, the network server further includes a determining module 810. In this embodiment, the receiving module 800 is further configured to receive clock source loss information from the base station. The selecting module 806 selects a new clock reference base station from the base station set S2 confirmed by the confirmation module 802 according to the Preamble signal set S1 reported by the base station, and may select a new clock reference according to the foregoing method. After the base station, the selecting module 806 selects a new clock reference base station, the sending module 808 sends an indication message to the base station to scan the new clock reference base station. The receiving module 800 is further configured to receive a scan report from the base station, where the determining module 810 is configured according to the The scan report determines whether the base station can scan the new clock reference base station, and if so, triggers the selection module 806 to send the related information of the new clock reference base station to the sending module 808; if not, The selection module 806 is then triggered to reselect a new clock reference base station.

The embodiment of the present invention further provides a communication system, where the system includes a clock slave base station, and the clock slave station is communicably connected to the clock reference base station, and the clock slave base station is configured to receive the Preamble signal from the clock reference base station. Detecting the Preamble signal, determining a phase deviation from the clock reference base station, determining a frequency deviation from the clock reference base station according to the phase deviation, performing time synchronization using the determined phase deviation, and utilizing the frequency deviation Perform frequency synchronization.

Preferably, in the embodiment of the present invention, when the clock is synchronized from the base station, the start frame of the clock reference base station and the number of repetitions N may be determined, the N>=1, when the clock reference base station is determined. After the clock is determined by the base station to be synchronized, it is required to monitor the start frame of the clock reference base station, as may be the frame number of the start frame to be monitored. In the embodiment of the present invention, the determining the start of the to-be-listened The frame may be a frame in which the clock reference base station is randomly selected as the start frame. Preferably, the start frame to be monitored may be determined according to the start time and the synchronization period of the clock reference base station, so that the frame can be ensured. The clock from the base station can monitor the signal of the clock reference base station; further determining the number of repetitions of the intercept N, where N>=1, if the value of N can be 100 or 200, or even 1.

The clock measures, from the base station, the phase deviation from the Preamble signal for each received Preamble signal from the determined start frame, repeats the N times, and then takes the N measured phases. The deviation is averaged to obtain an average phase deviation, and the frequency deviation is determined according to the phase deviation obtained by the N measurements, and averaged to obtain an average frequency deviation. The local phase is adjusted by the average phase deviation, and the local frequency is adjusted according to the average frequency deviation, so as to achieve synchronization with the time and frequency of the clock reference base station. For the calculation method of the frequency offset, refer to the above formula 1.

After the clock is synchronized from the base station, normal operation is started. Preferably, the clock slave base station is further configured to determine a synchronization period, and when the synchronization period is reached, receiving the clock reference base station. The Preamble signal of the R-BS measures a phase deviation from the Preamble signal, determines a frequency offset based on the phase deviation, and performs a synchronization operation. The phase deviation is used to adjust the local time. Further, according to the frequency deviation, the local frequency is adjusted according to the determined frequency deviation, so as to achieve synchronization with the time and frequency of the clock reference base station. Determining the frequency deviation of the same clock reference base station according to the phase deviation may be determining the frequency deviation according to the method of Equation 1 above, then the Pi value is the phase deviation of the current detection, and Pj is the value detected by the previous synchronization period. The phase deviation to Ti, T - Tj is the synchronization period.

Further, in the embodiment of the present invention, the system further includes a network server, and the clock slave base station is further configured to scan the Preamble signal of the neighboring base station before the synchronization, and use the scanned Preamble signal of the neighboring base station as the set S1. Reported to the web server. The network server is configured to receive the Preamble signal set S1 reported from the base station, and confirm the base station to which each Preamble signal in the set S1 belongs, form a base station set S2, and select a clock reference from the base station set S2. The base station, according to each base station in the set of base stations S2, queries the clock state of the base station, and selects the base station with the higher priority clock state as the clock reference base station. Preferably, the base station that can select the highest priority clock state is used as the clock reference base station. Further, if a plurality of Preamble signals in the set S1 belong to the selected clock reference base station, preferably, the Preamble signal with the highest signal quality is selected, such as the RSSI maximum or the CINR maximum. The network server is configured to notify the clock slave base station of the confirmed clock reference base station, and the related information of the clock reference base station includes a clock state of the clock reference base station, a Preamble signal sequence number, and the clock reference. The frequency of the base station; further, the related information may further include a start time of the clock reference base station and a synchronization period thereof. Optionally, in the embodiment of the present invention, if the network server cannot confirm the base station to which each Preamble signal in the set S1 belongs, the Preamble signal with the best signal quality may be self-planned according to the frequency and the confirmed Preamble may be confirmed. Signal information is sent to the clock from the base station. In this embodiment, if the network server finds that it is unable to confirm the base station to which each Preamble signal belongs in the set S1, it may determine, according to the result of the frequency self-planning, whether each Preamble signal in the set S1 has the same The base station's same frequency Preamble signal, if any, is preferred, from these same frequency Preamble Selecting a Preamble signal with the highest signal quality for the base station as a clock reference; if not, selecting a Preamble signal with the highest signal quality from the set S1 for the base station to use as a clock reference.

Further, in the embodiment of the present invention, the clock slave base station is further configured to report the network server if the clock source is lost, and the network server is further configured to select a new one from the set of Preamble signals reported by the base station from the clock. The clock reference base station indicates that the clock scans the new clock reference base station from the base station. After receiving the indication from the base station to the network server, the clock scans the new clock reference base station and reports the scan result to the network server.

In this embodiment, the Preamble signal of the clock reference base station is scanned, and the signal strength is measured, and the scanned result is reported to the network server. The network server determines, according to the scan result reported by the base station, whether the new clock reference base station can be scanned. If yes, the new clock reference base station information is notified to the clock slave base station, indicating that the clock is synchronized from the base station using the new clock reference base station, otherwise the new clock reference base station is reselected.

A person skilled in the art can understand that all or part of the steps of implementing the above embodiments can be completed by a program to instruct related hardware, and the program can be stored in a computer readable storage medium. , including the following steps:

The clock receives a Preamble signal from the base reference base station from the base station;

Detecting the Preamble signal, determining a phase deviation from the clock reference base station; determining a frequency deviation from the clock reference base station according to the phase deviation;

The above-mentioned storage medium may be a read only memory, a magnetic disk or an optical disk or the like.

The above is only a preferred 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 within the technical scope disclosed by the present invention. Alternatives are intended to be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

Claim

A synchronization method, comprising:

2. The method according to claim 1, wherein the clock further comprises: before receiving the preamble signal from the clock reference base station from the base station:

The clock is determined by the base station to listen to the start frame of the clock reference base station and the number of repetitions N, where N>=1;

Receiving a preamble signal from the clock reference base station from the determined start frame; detecting the preamble signal, determining a phase offset from the clock reference base station, determining, according to the phase offset, the clock reference base station Frequency deviation, repeating the N times as described above;

The determined phase deviation and the frequency deviation are respectively averaged to obtain an average phase deviation and a uniform frequency deviation, and the average phase deviation is used for time synchronization, and the average frequency deviation is used for frequency synchronization.

3. The method according to claim 1, comprising:

The clock predetermines a synchronization period from the base station;

When the synchronization period is reached, the clock receives a preamble signal from the base station from the clock reference base station; detects the preamble signal, and determines a phase deviation from the clock reference base station;

The method according to any one of claims 1 to 3, wherein the determining the frequency deviation from the clock reference base station according to the phase deviation is specifically determining the frequency deviation according to the following formula:

Frequency deviation = ( Pi - Pj ) / ( Ti - Tj )

The Pi is the phase deviation detected by the ith time, and Ti is the time when the phase deviation is detected for the ith time. Pj is the phase deviation detected at the jth time, and Tj is the time at which the phase deviation is detected for the jth time, i>j.

The method according to claim 1, wherein the clock slave base station determines the clock reference base station before receiving the preamble signal from the clock reference base station, and includes:

The clock scans the neighboring base station from the base station, and reports the preamble signal of the scanned neighboring base station to the network server as the set S1;

Determining, by the network server, a base station to which the preamble signal in the set S1 belongs, forming a set of base stations

S2;

Selecting a clock reference base station from the set of base stations S2;

The selected clock reference base station information is sent to the clock slave base station.

The method according to claim 5, wherein the selecting a clock reference base station from the set of base stations S2 comprises:

The network server queries the clock status of each base station in the base station set S2; and selects the base station with the highest priority clock status as the clock reference base station.

The method according to claim 5, wherein the information related to the clock reference base station comprises:

The clock refers to the clock state of the base station, the preamble sequence number, and the frequency point.

The method according to claim 7, wherein the clock reference base station related information further comprises: a start time and a synchronization period of the clock reference base station.

9. The method of claim 5, further comprising:

If the network server cannot determine the base station to which the preamble signal in the set S1 belongs, the preamble signal with the best signal quality in the set S1 is self-planned according to the frequency;

Transmitting the information of the selected preamble to the clock slave base station.

10. The method of claim 5, wherein the method further comprises:

The clock is reported from the base station to the network server if the clock source is lost during the synchronization process; the network server selects a new clock reference base station from the set of preamble signals S1 reported by the base station from the clock, indicating the clock from the clock The base station scans the new clock reference base station;

The network server receives a scan report from the base station from the clock, if it is determined that the clock is from The base station can scan the new clock reference base station, and instruct the clock to synchronize from the base station using the new clock reference base station, otherwise, return to the network server to select from the set of preamble signals S1 reported by the base station from the base station. The new clock refers to the base station, and the step of instructing the clock to scan the new clock reference base station from the base station.

A base station, comprising: a receiving module (700), a detecting module (702), and a synchronization module (704),

The receiving module (700) is configured to receive a preamble signal from a clock reference base station, and forward the preamble signal to the detecting module (702);

The detecting module (702) is configured to detect the preamble signal, determine a phase deviation from the clock reference base station, and determine a frequency deviation from the clock reference base station according to the phase deviation;

The synchronization module (704) is configured to perform time synchronization according to the determined phase deviation, and perform frequency synchronization according to the frequency deviation.

The base station according to claim 11, wherein the synchronization module (704) further includes a digital to analog conversion module (7040) and a thermostatically controlled crystal oscillator (7042).

The digital-to-analog conversion module (7040) is configured to convert the phase deviation to output a voltage control voltage; the constant temperature control crystal oscillator (7042) is configured to adjust a local frequency according to the voltage control voltage, according to The phase deviation adjusts the local time.

The digital-to-analog conversion module (7040) is configured to convert the phase deviation and the frequency deviation, and output a voltage control voltage;

The thermostatically controlled crystal oscillator (7042) is configured to adjust a local frequency and a local time according to the voltage controlled voltage.

14. A network server, comprising: a receiving module (800), an acknowledgment module (802), a storage module (804), a selection module (806), and a sending module (808),

The receiving module (800) is configured to receive a preamble signal set S1 from a base station;

The confirmation module (802) is configured to confirm a base station to which each preamble signal in the set S1 belongs, Forming a base station set S2;

The storage module (804) is configured to store a clock state of the base station;

The selecting module ( 806 ) is configured to select a clock reference base station from the base station set S2 confirmed by the confirming module ( 802 ) according to a clock state of the base station stored by the storage module ( 804 ), and select a selected clock Sending information about the base station to the sending module (808);

The sending module (808) is configured to send related information of the clock reference base station to the base station.

15. The network server according to claim 14, wherein:

The acknowledgment module (802) is further configured to send the set S1 to the selection module if the base station of each preamble in the set S1 cannot be confirmed;

The selection module (806) is further configured to: modulate a preamble signal with the best signal quality according to a frequency self-planning and send the information of the confirmed preamble signal to the sending module;

The sending module (808) is further configured to send information of the acknowledged preamble to the base station.

The network server according to claim 14, wherein the network server further comprises a determining module (810),

The receiving module (800) is further configured to receive clock source loss information from the base station; the selecting module (806) is further configured to use a preamble signal reported by the acknowledgment module (802) according to the base station Selecting a new clock reference base station in the set of base stations S2 confirmed by the set S1;

The sending module (808) is further configured to send an indication message to the base station to scan the new clock reference base station;

The receiving module (800) is further configured to receive a scan report from the base station;

The determining module (810) is further configured to determine, according to the scan report, whether the base station can scan the new clock reference base station, and if so, trigger the selection module (806) to use the new clock. The relevant information of the reference base station is sent to the sending module (808); if not, the selecting module (806) is triggered to reselect the new clock reference base station.

17. A communication system, the system comprising a clock slave base station, the clock The base station is communicably connected to the clock reference base station;

The clock slave base station is configured to receive a preamble signal from a clock reference base station, detect the preamble signal, determine a phase deviation from the clock reference base station, and determine a frequency offset from the clock reference base station according to the phase deviation, Time synchronization is performed using the determined phase deviation, and frequency synchronization is performed using the frequency deviation.

The system according to claim 17, wherein the clock slave base station is further configured to determine a starting frame for listening to the clock reference base station and a repetition number N;

The clock slave base station is configured to receive a preamble signal from the clock reference base station from the determined start frame; detect the preamble signal, determine a phase deviation from the clock reference base station, according to the phase deviation Determining a frequency deviation from the clock reference base station, repeating the N times in this manner; averaging the determined phase deviation and the frequency deviation, respectively, to obtain an average phase deviation and an average frequency deviation, using the average phase deviation Time synchronization is performed, and frequency synchronization is performed using the average frequency deviation.

The system according to claim 17, wherein the clock slave base station is further configured to determine a synchronization period, and when the synchronization period is reached, receive a preamble signal from the clock reference base station, and measure the The phase deviation of the preamble signal determines the frequency deviation based on the phase deviation, and performs a synchronous operation.

The system according to any one of claims 17 to 19, wherein the system further comprises a network server;

The clock slave base station is further configured to scan the neighboring base station, and report the preamble signal of the scanned neighboring base station to the network server as the set S1;

The network server is configured to determine a base station to which the preamble signal in the set S1 belongs, to form a base station set S2, select a clock reference base station from the base station set S2, and send related information of the selected clock reference base station to the The clock is from the base station.

21. The system of claim 20, wherein:

The network server is further configured to: if the base station to which the preamble signal in the set S1 belongs cannot be determined, confirm the preamble signal with the best signal quality in the set S1 according to the frequency self-planning; and select the preamble Signal information is sent to the clock from the base station.

22. The system of claim 20, wherein:

The clock slave base station is further configured to: if the clock source is lost during the synchronization process, the network server is >3⁄4;

The network server is further configured to select a new clock reference base station from the set of preamble signals S1 reported by the base station, and instruct the clock to scan the new clock reference base station from the base station; receive the clock from the clock Scanning from the base station, if it is determined that the clock can be scanned from the base station to the new clock reference base station, indicating that the clock is synchronized from the base station using the new clock reference base station, otherwise, the clock is re-sent from the base station. Select a new clock reference time.