WO2012075921A1 - 实现时间同步的方法及基站 - Google Patents

实现时间同步的方法及基站 Download PDF

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Publication number
WO2012075921A1
WO2012075921A1 PCT/CN2011/083500 CN2011083500W WO2012075921A1 WO 2012075921 A1 WO2012075921 A1 WO 2012075921A1 CN 2011083500 W CN2011083500 W CN 2011083500W WO 2012075921 A1 WO2012075921 A1 WO 2012075921A1
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Prior art keywords
base station
time
clock source
system time
source base
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PCT/CN2011/083500
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English (en)
French (fr)
Inventor
宋照红
张大刚
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华为技术有限公司
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Publication of WO2012075921A1 publication Critical patent/WO2012075921A1/zh

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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W56/00Synchronisation arrangements
    • H04W56/001Synchronization between nodes

Definitions

  • the present invention relates to the field of communications technologies, and in particular, to a method and a base station for implementing time synchronization. Background technique
  • the mobile communication network requires transmission synchronization between the network elements. Therefore, each network element has strict requirements on the accuracy of the clock signal.
  • base stations generally obtain absolute time by two methods.
  • the base station obtains an absolute time from the satellite by synchronizing a satellite star card, such as a GPS (Globa l Postation System) satellite card.
  • a satellite star card such as a GPS (Globa l Postation System) satellite card.
  • the base station supports IEEE 1588V2 (The Ins t i tute of Elect rica l and
  • Protocol clock server for absolute time.
  • the inventors have found that at least the following problems exist in the prior art: For the first method, since the GPS star card has certain requirements for the installed position, it is susceptible to electromagnetic environment interference, and therefore, the base station follows this. The absolute time reliability obtained by the method is not high; for the second method, the devices in the mobile communication network are required to support the IEEE 1588V2 protocol, but devices such as routers and switches in the mobile communication network usually do not support the IEEE 1588V2 protocol, so It is difficult for the base station to obtain absolute time, which also affects the reliability of the base station to obtain absolute system time. Summary of the invention
  • the embodiments of the present invention provide a method and a base station for implementing time synchronization, so as to improve the reliability of the base station to be synchronized to obtain absolute system time.
  • a method for implementing time synchronization including:
  • a base station comprising:
  • An information acquiring unit configured to acquire information about a clock source base station
  • a downlink synchronization unit configured to perform downlink synchronization with the clock source base station according to information of the clock source base station
  • a parameter obtaining unit configured to obtain an absolute system time reference parameter
  • a first time synchronization unit configured to calculate an absolute system time according to the absolute system time reference parameter, and perform system time synchronization with the clock source base station by using the absolute system time.
  • the method for implementing time synchronization and the base station provided by the embodiment of the present invention first obtain information of a clock source base station, perform downlink synchronization with the clock source base station according to information of the clock source base station, and then obtain an absolute system time reference parameter, and according to The absolute system time reference parameter calculates an absolute system time, and then uses the absolute system time to perform system time synchronization with the clock source base station. Therefore, with the technical solution of the embodiment of the present invention, if the GPS star card is not installed or the router and the switch do not support the IEEE 1588V2 protocol, the absolute system time reference parameter can still be obtained, and the absolute system time is calculated according to the absolute system time reference parameter. So as to synchronize with the system time of the clock source base station. Therefore, the technical solution of the embodiment of the present invention improves the reliability of the base station to obtain absolute system time.
  • FIG. 1 is a flowchart of a method for implementing time synchronization according to an embodiment of the present invention
  • FIG. 1 is a flowchart of a method for implementing time synchronization according to Embodiment 2 of the present invention
  • FIG. 3 is a flowchart of a method for implementing time synchronization according to Embodiment 3 of the present invention
  • FIG. 5 is a schematic diagram of a base station according to Embodiment 5 of the present invention.
  • FIG. 6 is a schematic diagram of a first time synchronization unit according to Embodiment 5 of the present invention
  • FIG. 7 is still another schematic diagram of a base station according to Embodiment 5 of the present invention.
  • WiMAX WiMAX (Wor ldwide Interoperab i ty for Microwave Acces s) mobile communication system as an example.
  • the first embodiment of the present invention provides a method for implementing time synchronization, including: Step 11: The base station to be synchronized acquires information of a clock source base station.
  • the base station to be synchronized refers to a base station that cannot obtain an absolute time without a clock source such as a GPS star card or an IEEE 1588V2.
  • the clock source base station refers to a base station that has a clock source such as a GPS star card or an IEEE 1588V2 and can obtain an absolute time.
  • the information of the clock source base station may include a name of the clock source base station, or a number, and the like.
  • the manner in which the to-be-synchronized base station acquires the information of the clock source base station may be:
  • the method is as follows:
  • the base station to be synchronized sends a clock source request message to the network management device, and receives a clock source request response message sent by the network management device, where the clock source request response message includes information of the clock source base station.
  • the base station to be synchronized receives information of a clock source base station transmitted by the network management device.
  • the difference between the second mode and the first mode is that, in the second mode, the base station to be synchronized does not need to actively send the clock source request message, and can receive the information of the clock source base station sent by the network management device.
  • the network management device may include: a GW (Gateway), an EMS (Element Managed System), and the like.
  • Step 12 The base station to be synchronized performs downlink synchronization with the clock source base station according to information of the clock source base station.
  • the base station to be synchronized scans the downlink synchronization channel of the clock source base station to follow the time.
  • the clock source base station performs frame alignment, and then reads the reference frame number in the control channel message of the clock source base station, and the base station to be synchronized can use the reference frame number and the clock source base station to synchronize the frame number of the single unit.
  • Step 1 3 The base station to be synchronized acquires an absolute system time reference parameter.
  • the absolute system time reference parameter may include: a system time parameter and a reference frame number.
  • the manner in which the base station to be synchronized obtains the absolute system time reference parameter may be: Method 1: The base station to be synchronized reads the control channel message of the clock source base station to obtain the system time parameter and the reference frame number.
  • the base station to be synchronized acquires the system time parameter from the network management device, and reads a control channel message of the clock source base station to obtain the reference frame number.
  • the base station to be synchronized acquires the system time parameter from the clock source base station through the network management device, and reads the control channel message of the clock source base station to obtain the reference frame number.
  • the first method, the second method, and the third method are different in the method: in the first method, the control channel of the clock source base station is cancelled, the packet is carried, and the time parameter of the system is carried, and the base station to be synchronized can directly acquire the system time parameter; In the second mode, the control channel message of the clock source base station does not carry the system time parameter, and the to-be-synchronized base station acquires the system time parameter from the network management device; in mode 3, the clock source The control channel message of the base station carries the system time parameter, but the base station to be synchronized cannot directly obtain the system time parameter from the control channel message of the clock source base station, but acquires the system by the clock source base station through the network management device. System time parameter.
  • the first mode, the second mode, and the third mode are the same in that: the base station to be synchronized acquires the reference frame number from the control channel message of the clock source base station.
  • Step 14 The base station to be synchronized calculates an absolute system time according to the absolute system time reference parameter, and performs system time synchronization with the clock source base station by using the absolute system time.
  • the base station to be synchronized obtains a system frame number by using the system time parameter, and obtains the absolute time according to the system frame number, the system time parameter, and the reference frame number.
  • the system time parameter and the system frame number have the following correspondence relationship, and the system frame number can be calculated by the system time parameter, and the system frame number can be reversed.
  • the time parameters There are many specific calculation methods for the time parameters.
  • Y, M, D, H, M, and S represent the weights of year, month, day, hour, minute, and second, respectively, and y, m, d, h, m, and s represent year, month, day, and hour, respectively.
  • Actual value of minutes, seconds, seconds, FN stands for system frame number
  • Second stands for system time parameter
  • constant 200 means that in WiMAX air interface protocol 802. 16e, it is usually set to 200 frames per second (frame length 5ms), constant OxFFFFFF is because of WiMAX
  • the frame number length defined in the air interface protocol 802.16 is 3 bytes, and other communication systems may vary according to specific protocol specifications, and the frame numbers include all frame numbers in the WiMAX system.
  • the absolute system time reference parameter can still be obtained, and the absolute system time is calculated according to the absolute system time reference parameter. So as to synchronize with the system time of the clock source base station. Therefore, with the technical solution of the embodiment of the present invention, the reliability of the base station to obtain the absolute system time is improved.
  • the second embodiment of the present invention provides a method for implementing time synchronization.
  • the control channel message of the clock source base station simultaneously carries the system time parameter (AIR-SYSTIME) and the reference frame number (Frame Number). Specifically include:
  • Step 21 The base station to be synchronized acquires information of the clock source base station.
  • the manner in which the to-be-synchronized base station acquires the information of the clock source base station may be:
  • the base station to be synchronized sends a clock source request message Ge tTime_Reci to the GW/EMS (Gateway/Element Management Sys tem, gateway/element management system), and it is hoped that the absolute time can be obtained, and the network management device replies to the base station clock to be synchronized.
  • the source request response message Ge tTime_Rep and includes information of the clock source base station in the clock source request response message.
  • Manner 2 The base station to be synchronized does not need to send a clock source request message to the GW/EMS, but receives information of the clock source base station actively sent by the EMS.
  • Step 22 The base station to be synchronized performs downlink synchronization with the clock source base station according to information of the clock source base station. This step can be referred to step 12 in the first embodiment of the present invention.
  • Step 23 The base station to be synchronized acquires an absolute system time reference parameter.
  • any wireless system carries the reference frame number FN in the control channel message, and only some systems carry the system time in the control channel message.
  • the time parameter is an optional system in the control channel message, and the network management device requires the clock source base station to carry the system time parameter in the control channel message. Therefore, the absolute system time reference parameters carried by the clock source base station in its control channel message include: system time parameter AIR_SYSTIME and reference frame number FN.
  • the base station to be synchronized obtains the system time parameter AIR-SYSTIME and the reference frame number FN of the clock source base station by reading the absolute system time reference parameter in the control channel message of the clock source base station.
  • Step 24 The base station to be synchronized calculates an absolute system time according to the absolute system time reference parameter, and performs system time synchronization with the clock source base station by using the absolute system time.
  • the to-be-synchronized base station obtains the system frame number by using the system time parameter, and obtains the absolute system time according to the system frame number, the reference frame number, and the system time parameter.
  • Step 241 Obtain a system frame number from the system time parameter, that is, obtain FN ByAi rTime by AIR-SYSTIME, where the calculation formula is:
  • Y, M, D, H, M, and S represent the weights of year, month, day, hour, minute, and second, respectively, and y, m, d, h, m, and s represent year, month, day, and hour, respectively.
  • the actual value of minutes, seconds, seconds, FNByAi rTime represents the system frame number
  • AIR-SYSTIME represents the system time parameter (y_m_d_h_m_s)
  • the constant 200 refers to the normal setting of 200 frames per second (frame length 5ms) in the WiMAX air interface protocol 802.16e.
  • the constant OxFFFFFF is because the 802.16 protocol defines that the frame number length is 3 bytes, and other communication systems may vary according to specific definitions, and the frame numbers include all frame numbers in the WiMAX system.
  • Step 242 Obtain the absolute system time according to the system frame number, the reference frame number, and the system time parameter, where the calculation formula is:
  • FN represents the reference frame number
  • FNByAi rTime represents the system frame number
  • Ts represents the time constant (frame length, generally set to 5ms in the WiMAX protocol)
  • mi 1 1 i second represents the relative time in milliseconds
  • TIME represents the absolute value obtained.
  • System time y_m_d_h_m_s_ms).
  • the absolute system time TIME is slightly later than the real-time time of the clock source base station due to parameter transmission or calculation delay, etc.
  • the base station to be synchronized can obtain the absolute system time TIME.
  • the embodiment may further include the step 25 to implement real-time time synchronization between the base station to be synchronized and the clock source base station, but this step is not necessary for the embodiment.
  • Step 25 The base station to be synchronized acquires a real-time absolute time, and performs real-time time synchronization with the clock source base station by using the real-time absolute time.
  • the base station to be synchronized reads the control channel message of the clock source base station to obtain the real-time frame number, and then the base station to be synchronized obtains the clock according to the absolute system time, the real-time frame number, and the reference frame number.
  • the real-time absolute time of the source station is the real-time absolute time of the source station.
  • TIMErea l TIME + (FNrea l - FN) *Ts
  • TIME is the absolute system time (y_m_d_h_m_s_ms) obtained in step 24
  • FNrea l is the real-time frame number obtained by reading the clock source control channel message again
  • FN is the reference frame number already acquired in step 23
  • Ts is the time constant (The frame length is generally set to 5ms in the WiMAX protocol.)
  • TIMErea l is the real-time absolute time of the clock source station.
  • the base station to be synchronized performs real-time time synchronization with the clock source base station by using the real-time absolute time.
  • the to-be-synchronized base station can still parse and obtain the absolute system time reference from the control channel message of the clock source base station.
  • the parameter includes a system time parameter (AIR-SYSTIME) and a reference frame number FN, and calculates an absolute system time according to the absolute system time reference parameter, thereby realizing time synchronization between the base station to be synchronized and the clock source base station system, and further, Calculate the real-time absolute time by using the absolute system time to achieve the base station and clock to be synchronized Real-time time synchronization of the source base station, thereby improving the reliability of the base station to obtain real-time absolute time.
  • AIR-SYSTIME system time parameter
  • FN reference frame number
  • Embodiment 3 of the present invention provides a method for implementing time synchronization.
  • the to-be-synchronized base station acquires the system time parameter from the network management device, and obtains the reference frame number from the control channel message of the clock source base station. Specifically include:
  • Step 31 The base station to be synchronized acquires information of the clock source base station.
  • step 21 in the second embodiment of the present invention.
  • Step 32 The base station to be synchronized performs downlink synchronization with the clock source base station according to information of the clock source base station.
  • This step can be referred to step 12 in the first embodiment of the present invention.
  • Step 33 The base station to be synchronized acquires a reference frame number from the clock source base station.
  • control channel message of the clock source base station only carries the reference frame number, so that the base station to be synchronized can only obtain the reference frame number from the control channel message of the clock source base station.
  • Step 34 The base station to be synchronized acquires a system time parameter.
  • the air interface control channel message of the clock source base station does not carry the system time parameter, so the base station to be synchronized cannot obtain the system time parameter directly from the control channel message of the clock source base station, but can only obtain the system from the network management device.
  • Time parameters including:
  • the base station to be synchronized sends a reference time request message GetTime_Reci to the network management device, such as: GW or EMS or ClockServer (clock server), the network management device replies to the base station reference time request response message GetTime_Rep to be synchronized, and requests a response at the reference time.
  • the message carries the system time parameter.
  • Step 35 The base station to be synchronized calculates an absolute system time according to an absolute system time reference parameter, and performs system time synchronization with the clock source base station by using the absolute system time.
  • the absolute system time reference parameters include a system time parameter NET-SYSTIME and a reference frame number FN.
  • the base station to be synchronized obtains the system frame number by using the system time parameter, and obtains the absolute system time according to the system frame number, the reference frame number, and the system time parameter.
  • Y, M, D, H, M, and S represent the weights of year, month, day, hour, minute, and second, respectively
  • y, m, d, h, m, and s represent year, month, day, and hour, respectively.
  • NET-SYSTIME represents the system time parameter (y_m_d_h_m_s)
  • constant 200 means that the WiMAX air interface protocol 802.16e is normally set to 200 frames per second (frame length 5ms)
  • the constant OxFFFFFF is because the frame number length defined in the WiMAX air interface protocol 802.16 is 3 bytes, and other communication systems may be different according to specific protocol specifications, and the frame numbers include all frame numbers in the WiMAX system.
  • Step 352 Obtain the absolute system time according to the system frame number, the reference frame number, and the system time parameter, where the calculation formula is:
  • TIME NET-SYSTIME + mi l l i second
  • FN represents the reference frame number
  • FNByNe tTime represents the system frame number
  • Ts represents the time constant (frame length, WiMAX base station is generally set to 5ms)
  • mi lli second represents the relative time in milliseconds
  • TIME represents the absolute system time obtained ( Y_m_d_h_m_s_ms).
  • the absolute system time TIME is slightly later than the real-time time of the clock source base station due to parameter transmission or calculation delay, etc.
  • the base station to be synchronized can obtain the absolute system time TIME.
  • the embodiment may further include step 36 to implement real-time time synchronization between the base station to be synchronized and the clock source base station, but this step is not necessary in this embodiment.
  • Step 36 The base station to be synchronized further calculates a real-time absolute time, and performs real-time time synchronization with the clock source base station by using the real-time absolute time.
  • the base station to be synchronized reads the control channel message of the clock source base station to obtain the real-time frame number, and then the base station to be synchronized obtains the clock according to the absolute system time, the real-time frame number, and the reference frame number.
  • the real-time absolute time of the source station is the real-time absolute time of the source station.
  • TIMErea l TIME + (FNrea l - FN) *Ts
  • TIME is the absolute system time that has been obtained (y_m_d_h_m_s_ms)
  • FNrea l is read again Take the real-time frame number obtained by the clock source control channel message.
  • FN is the reference frame number that has been acquired when calculating TIME.
  • Ts is the time constant (frame length, which is generally set to 5ms in WiMAX protocol).
  • TIMErea l is the real-time clock source station. Absolute time.
  • the base station to be synchronized performs real-time time synchronization with the clock source base station by using the real-time absolute time.
  • the to-be-synchronized base station acquires the system time parameter from the GW/EMS/ClockServer, and then receives the control channel from the clock source base station.
  • the reference frame number FN is parsed and obtained in the message, and the absolute system time is calculated according to the absolute system time reference parameter, so that the base station to be synchronized and the clock source base station system are time synchronized, and further, the absolute system time can be used to obtain real-time.
  • Absolute time, real-time synchronization of the base station to be synchronized with the clock source base station thereby improving the reliability of the base station to obtain real-time absolute time.
  • Embodiment 4 of the present invention provides a method for implementing time synchronization.
  • the base station to be synchronized acquires the system time parameter from the clock source base station through the network management device, and obtains the reference frame number from the control channel message of the clock source base station. Specifically include:
  • Step 41 The base station to be synchronized acquires information of the clock source base station.
  • step 21 in the second embodiment of the present invention.
  • Step 42 The base station to be synchronized performs downlink synchronization with the clock source base station according to information of the clock source base station.
  • This step can be referred to step 12 in the first embodiment of the present invention.
  • Step 43 The base station to be synchronized acquires a reference frame number from the clock source base station.
  • the base station to be synchronized can only obtain the reference frame number from the control channel message of the clock source base station.
  • Step 44 The base station to be synchronized acquires a system time parameter.
  • the control channel message of the clock source base station cannot carry the system time parameter (if the communication system control channel message does not support the time parameter), the base station to be synchronized cannot obtain the system time directly from the control channel message of the clock source base station.
  • Parameters, and can only be managed from the clock through the network management device The source base station obtains the system time parameter, and specifically includes:
  • the base station to be synchronized sends a reference time request message GetTime_Reci to the clock source base station through a network management device, such as a GW or an EMS or a ClockServer (clock server), and then the clock source base station replies to the reference time request response message GetTime_Rep through the network management device, and
  • the reference time request response message includes a system time parameter.
  • Step 45 The base station to be synchronized calculates an absolute system time according to the absolute system time reference parameter, and performs system time synchronization with the clock source base station by using the absolute system time.
  • the absolute system time reference parameters include a system time parameter NET-SYSTIME and a reference frame number FN.
  • the base station to be synchronized obtains the system frame number by using the system time parameter, and obtains the absolute system time according to the system frame number, the reference frame number, and the system time parameter.
  • Step 451 Obtain a system frame number from the system time parameter, that is, obtain a FNByNetTime by using NET_SYSTIME, where the calculation formula is:
  • NET_SYSTIME (Y*y+M*m+D*d+H*h+M*m+S* s)
  • Y, M, D, H, M, and S represent the weights of year, month, day, hour, minute, and second, respectively, and y, m, d, h, m, and s represent year, month, day, and hour, respectively.
  • the actual value of minutes, seconds, seconds, FNByNetTime represents the system frame number
  • NET-SYSTIME represents the system time parameter (y_m_d_h_m_s)
  • the constant 200 refers to the usual setting of 200 frames per second (frame length 5ms) in the WiMAX air interface protocol 802.16e.
  • the constant OxFFFFFF is because the frame number length defined in the WiMAX air interface protocol 802.16 is 3 bytes, and other communication systems may be different according to the specific protocol, and the frame number includes all frame numbers in the WiMAX system.
  • Step 452 Obtain the absolute system time according to the system frame number, the reference frame number, and the system time parameter, where the calculation formula is:
  • TIME NET-SYSTIME + mi l l i second
  • this embodiment may further include step 46 to implement real-time time synchronization between the base station to be synchronized and the clock source base station, but this step is not necessary in this embodiment.
  • Step 46 The base station to be synchronized further calculates a real-time absolute time, and performs real-time time synchronization with the clock source base station by using the real-time absolute time.
  • the base station to be synchronized reads the control channel message of the clock source base station to obtain the real-time frame number, and then the base station to be synchronized obtains the clock according to the absolute system time, the real-time frame number, and the reference frame number.
  • the real-time absolute time of the source station is the real-time absolute time of the source station.
  • TIMEreal TIME + (FNreal - FN) *Ts
  • TIME is the absolute system time (y_m_d_h_m_s_ms) that has been obtained
  • FNreal is the real-time frame number obtained by reading the clock source control channel message again
  • FN is the reference frame number that has been acquired when calculating TIME
  • Ts is the time constant (frame length, The WiMAX protocol is generally set to 5ms)
  • TIMEreal is the real-time absolute time of the clock source station.
  • the base station to be synchronized performs real-time time synchronization with the clock source base station by using the real-time absolute time.
  • the to-be-synchronized base station acquires the system time parameter by the clock source base station through the GW/EMS/ClockServer.
  • the reference frame number FN is parsed and obtained from the control channel message of the clock source base station, and the absolute system time is calculated according to the absolute system time reference parameter, so that the base station to be synchronized and the clock source base station system are time synchronized, and further utilized.
  • the absolute system time obtains the real-time absolute time, and synchronizes with the real-time time of the clock source base station, thereby improving the reliability of the base station acquiring the real-time absolute time.
  • the base station includes: an information acquiring unit 51, configured to acquire information of a clock source base station; and a downlink synchronization unit 52, configured to use, according to information of the clock source base station, the clock source base station Performing downlink synchronization; a parameter obtaining unit 53, configured to acquire an absolute system time reference
  • the first time synchronization unit 54 is configured to calculate an absolute system time according to the absolute system time reference parameter, and perform system time synchronization by using the absolute system time.
  • the clock source base station refers to a base station that has a GPS star card or an IEEE 1588 V2 clock source, and can obtain an absolute time.
  • the information of the clock source base station may include a name of a clock source base station, or a number, and the like.
  • the information acquiring unit may obtain an absolute system time reference parameter in at least two manners, as described in the method embodiment.
  • the information acquiring unit 51 may specifically include: a request sending module, configured to send a clock source request message to the network management device; and a message receiving module, configured to receive a clock source request response message sent by the network management device, where The clock source request response message includes information of the clock source base station.
  • the information acquiring unit 51 may be specifically configured to receive information of a clock source base station sent by the network management device.
  • the downlink synchronization unit 52 may be specifically configured to scan a downlink synchronization channel of the specified clock source base station to perform frame alignment with the clock source base station, and then read the control channel message of the clock source base station. Referring to the frame number, the base station to be synchronized and the clock source base station can synchronize the frame number of the package.
  • the absolute system time reference parameters may include: a system time parameter and a reference frame number. Therefore, the parameter obtaining unit 53 may be specifically configured to read a control channel message of the clock source base station, and obtain the system time parameter and a reference frame number.
  • the parameter obtaining unit 53 may be specifically configured to acquire the system time parameter by the network management device, and read the control channel message of the clock source base station to obtain the reference frame number.
  • the parameter obtaining unit 53 may include: a message sending module, configured to send a reference time request message to the network management device; and a message receiving module, configured to send a reference time request response message to the network management device And including the system time parameter in the reference time request response message.
  • the parameter obtaining unit 53 may be specifically configured to acquire the system time parameter by the clock source base station by using a network management device, read a control channel of the clock source base station, and obtain the reference frame number.
  • the parameter obtaining unit 53 may include: a message sending module, configured to send a reference time request to the clock source base station by using the network management device;
  • the receiving module is configured to receive a reference time request response message sent by the clock source base station by using the network management device, and include the system time parameter in the reference time request response message.
  • the first time synchronization unit 54 includes: a first calculation module 541, configured to obtain a system frame number by using the system time parameter; and a second calculation module 542, configured to use the system frame according to the system
  • the system time parameter and the reference frame number obtain the absolute system time;
  • the time synchronization module 543 is configured to perform system time synchronization with the clock source base station by using the absolute system time.
  • the working principle of the time synchronization unit 54 can be referred to the description in the foregoing method embodiments.
  • the base station may further include: a real-time frame, when the TIME is slightly later than the real-time time of the clock source base station due to parameter transmission or calculation delay, and the like, and the time precision is required.
  • the number obtaining unit 55 is configured to read a control channel message of the clock source base station to obtain a real-time frame number
  • a second time synchronization unit 56 configured to obtain a clock source station according to the absolute system time, the real-time frame number, and the reference frame number. Real-time absolute time, and real-time time synchronization with the clock source base station using the real-time absolute time.
  • the base station according to the fifth embodiment of the present invention can still obtain the absolute system time reference parameter without calculating the GPS star card or the router and the switch do not support the IEEE 1588V2 protocol, and calculate the absolute system time according to the absolute system time reference parameter. Therefore, the time synchronization between the base station to be synchronized and the clock source base station system is realized, and the real-time absolute time can be further calculated according to the absolute system time, thereby achieving real-time synchronization with the clock source base station. Therefore, the base station according to Embodiment 5 of the present invention improves the reliability of the base station to acquire the real-time absolute time.
  • the method for implementing time synchronization and the base station provided by the embodiment of the present invention first acquire information of a clock source base station, and then perform downlink synchronization with the clock source base station according to information of the clock source base station, and then acquire an absolute system.
  • the time reference parameter further calculates an absolute system time according to the absolute system time reference parameter, and performs system time synchronization with the clock source base station by using the absolute system time. Therefore, the method for implementing time synchronization and the base station provided by the embodiment of the present invention improve the base station to be synchronized The reliability of communication.

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  • Mobile Radio Communication Systems (AREA)

Abstract

本发明实施例公开了一种实现时间同步的方法及基站,涉及通信技术领域,为提高基站获取绝对系统时间的可靠性而发明。所述方法包括:获取时钟源基站的信息;根据所述时钟源基站的信息与所述时钟源基站进行下行同步;获取绝对系统时间参考参数;根据所述绝对系统时间参考参数计算绝对系统时间,并利用所述绝对系统时间与时钟源基站进行系统时间同步。

Description

实现时间同步的方法 SL^站 技术领域
本发明涉及通信技术领域, 尤其涉及一种实现时间同步的方法及基站。 背景技术
移动通信网络为实现传输资源的时分复用等, 要求各网元间保持传输同步, 因此各网元对时钟信号精度有严格的要求。 目前基站一般通过两种方法获取绝 对时间。
方法一、 基站通过同步卫星星卡, 如 GPS (Globa l Pos i t ioning Sys tem, 全 球定位系统)星卡, 从卫星获取绝对时间。
方法二、 基站通过支持 IEEE 1588V2 ( The Ins t i tute of Elect r ica l and
Elect roni cs Eng ineers 1588Vers ion2 , 网络测量和控制系统的精密时钟同步 标准版本 2 )协议的时钟服务器获取绝对时间。
在基站实现上述获取绝对时间的过程中, 发明人发现现有技术中至少存在 如下问题: 对于方法一, 由于 GPS 星卡对于安装的位置有一定要求, 易受到电 磁环境干扰, 因此, 基站按照这种方法获得的绝对时间的可靠性不高;对于方法 二, 需要移动通信网络中的设备都支持 IEEE 1588V2 协议, 可是目前移动通信 网络中的路由器和交换机等设备通常不支持 IEEE 1588V2 协议, 故使得基站获 得绝对时间有一定的难度, 从而也影响了基站获取绝对系统时间的可靠性。 发明内容
本发明实施例提供一种实现时间同步的方法及基站, 以提高待同步基站获 取绝对系统时间的可靠性。
本发明实施例采用如下技术方案:
一种实现时间同步方法, 包括:
获取时钟源基站的信息;
根据所述时钟源基站的信息与所述时钟源基站进行下行同步; 根据所述绝对系统时间参考参数计算绝对系统时间, 并利用所述绝对 系统时间与所述时钟源基站进行系统时间同步。
一种基站, 包括:
信息获取单元, 用于获取时钟源基站的信息;
下行同步单元, 用于根据所述时钟源基站的信息与所述时钟源基站进 行下行同步;
参数获取单元, 用于获取绝对系统时间参考参数;
第一时间同步单元, 用于根据所述绝对系统时间参考参数计算绝对系 统时间, 并利用所述绝对系统时间与所述时钟源基站进行系统时间同步。
本发明实施例提供的实现时间同步的方法及基站, 首先获取时钟源基站的 信息,并根据所述时钟源基站的信息与该时钟源基站进行下行同步, 然后获取 绝对系统时间参考参数, 并根据所述绝对系统时间参考参数计算绝对系统时间, 而后利用所述绝对系统时间与所述时钟源基站进行系统时间同步。 因而, 利用 本发明实施例的技术方案,在没有安装 GPS星卡或者路由器和交换机不支持 IEEE 1588V2协议的情况下, 仍能获取绝对系统时间参考参数, 并根据绝对系统时间 参考参数计算绝对系统时间, 从而做到与时钟源基站的系统时间同步。 因此, 利用本发明实施例的技术方案, 提高了基站获取绝对系统时间的可靠性。
附图说明
为了更清楚地说明本发明实施例的技术方案, 下面将对实施例描述中所需 要使用的附图作一筒单地介绍, 显而易见地, 下面描述中的附图仅仅是本发明 的一些实施例, 对于本领域普通技术人员来讲, 在不付出创造性劳动的前提下, 还可以根据这些附图获得其他的附图。
图 1为本发明实施例一实现时间同步的方法的流程图;
图 1为本发明实施例二实现时间同步的方法的流程图;
图 3为本发明实施例三实现时间同步的方法的流程图;
图 4为本发明实施例四实现时间同步的方法的流程图;
图 5为本发明实施例五基站的示意图;
图 6为本发明实施例五中第一时间同步单元的示意图; 图 7为本发明实施例五中基站的又一示意图。
具体实施方式
下面将结合本发明实施例中的附图, 对本发明实施例中的技术方案进行清 楚、 完整地描述, 显然, 所描述的实施例仅仅是本发明一部分实施例, 而不是 全部的实施例。 基于本发明中的实施例, 本领域普通技术人员在没有做出创造 性劳动前提下所获得的所有其他实施例, 都属于本发明保护的范围。
我们以 WiMAX ( Wor ldwide Interoperab i l i ty for Microwave Acces s )移 动通讯系统为例来进行描述。
如图 1所示, 本发明实施例一提供了一种实现时间同步方法, 包括: 步骤 11、 待同步基站获取时钟源基站的信息。
在本发明实施例中, 所述待同步基站是指, 没有 GPS星卡或 IEEE 1588V2 等时钟源, 无法获得绝对时间的基站。 所述时钟源基站是指有 GPS星卡或 IEEE 1588V2等时钟源, 可以获得绝对时间的基站。 其中, 所述时钟源基站的信息可 以包括时钟源基站的名称, 或者编号等信息。
其中, 所述待同步基站获取时钟源基站的信息的方式可以为:
方式一、待同步基站向网络管理设备发送时钟源请求消息, 并接收所述网 络管理设备发送的时钟源请求响应消息, 在所述时钟源请求响应消息中包 括所述时钟源基站的信息。
方式二、 待同步基站接收由所述网络管理设备发送的时钟源基站的信 息。
方式二与方式一的不同之处在于, 在方式二中, 待同步基站不需要主动发 送时钟源请求消息, 就可以接收由所述网络管理设备发送的时钟源基站的信 息。
其中, 在本发明实施例中, 所述网络管理设备可以包括: GW ( Gateway, 网关), EMS ( Element Manage Sys tem, 网元管理系统)等。
步骤 12、所述待同步基站根据所述时钟源基站的信息与所述时钟源基站进 行下行同步。
对于 WiMAX系统, 待同步基站扫描该时钟源基站的下行同步信道, 来跟时 钟源基站做到帧对齐, 再读取所述时钟源基站的控制信道消息中的参考帧号, 待同步基站利用所述参考帧号和时钟源基站可以做到筒单的帧号同步。
步骤 1 3、 所述待同步基站获取绝对系统时间参考参数。
在此步骤中, 所述绝对系统时间参考参数可以包括: 系统时间参数和参 考帧号。
其中, 所述待同步基站获取绝对系统时间参考参数的方式可以为: 方式一、 待同步基站读取所述时钟源基站的控制信道消息获取所述系 统时间参数和参考帧号。
方式二、 待同步基站从网络管理设备获取所述系统时间参数, 并读取 所述时钟源基站的控制信道消息获取所述参考帧号。
方式三、 待同步基站通过网络管理设备从所述时钟源基站获取所述系 统时间参数, 并读取所述时钟源基站的控制信道消息获取所述参考帧号。
方式一、 方式二和方式三的不同之处在于: 在方式一中, 所述时钟源 基站的控制信道消,包、携带所述系统时间参数, 所述待同步基站可以直接获 取系统时间参数; 而在方式二中, 所述时钟源基站的控制信道消息不携带 所述系统时间参数, 待同步基站是从所述网络管理设备获取所述系统时间 参数的; 在方式三中, 所述时钟源基站的控制信道消息携带所述系统时间 参数, 但待同步基站不能直接从所述时钟源基站的控制信道消息获取所述 系统时间参数, 而是通过网络管理设备由所述时钟源基站获取所述系统时 间参数。
方式一、 方式二和方式三的相同之处在于: 待同步基站都是从所述时 钟源基站的控制信道消息中获取所述参考帧号。
步骤 14、 所述待同步基站根据所述绝对系统时间参考参数计算绝对系 统时间, 并利用所述绝对系统时间与所述时钟源基站进行系统时间同步。
其中, 所述待同步基站利用所述系统时间参数获得系统帧号, 再根 据所述系统帧号、 所述系统时间参数和所述参考帧号获得所述绝对时间。
其中, 在本发明实施例中, 所述系统时间参数和所述系统帧号之间有如下 对应关系, 由系统时间参数可以计算出系统帧号, 由系统帧号又可以反推出系 统时间参数, 具体计算方法可以有多种, 这里举例一种为:
Second= (Y*y+M*m+D*d+H*h+M*m+S* s)
FN= ( Second*200 ) % OxFFFFFF
其中, Y、 M、 D、 H、 M、 S分别代表年、 月、 日、 小时、 分钟、 秒的权值, y、 m、 d、 h、 m、 s分别代表年、 月、 日、 小时、 分钟、 秒的实际值, FN代表系统 帧号, Second代表系统时间参数, 常量 200是指在 WiMAX空口协议 802. 16e中 每秒通常设置为 200帧(帧长 5ms ),常量 OxFFFFFF是因为 WiMAX空口协议 802. 16 中定义帧号长度是 3个字节, 其他通讯系统根据具体协议规定会有所不同, 所 述帧号包括 WiMAX系统中的所有帧号。
因而, 利用本发明实施例的技术方案, 在没有安装 GPS星卡或者路由器 和交换机不支持 IEEE 1588V2协议的情况下, 仍能获取绝对系统时间参考参数, 并根据绝对系统时间参考参数计算绝对系统时间, 从而做到与时钟源基站的系 统时间同步。 因此, 利用本发明实施例的技术方案, 提高了基站获取绝对系 统时间的可靠性。
以下结合具体的实施例, 详细描述一下本发明实施例实现时间同步的方法。 如图 2 所示, 本发明实施例二提供了一种实现时间同步的方法。 其中, 在 本发明实施例二中, 时钟源基站的控制信道消息同时携带系统时间参数 ( AIR-SYSTIME ) 和参考帧号 (Frame Number ) 。 具体包括:
步骤 21、 待同步基站获取时钟源基站的信息。
其中, 所述待同步基站获取时钟源基站的信息的方式可以为:
方式一、 待同步基站向 GW/EMS ( Ga teway/E lement Manage Sys t em, 网关 / 网元管理系统)发送时钟源请求消息 Ge tTime_Reci , 希望能获得绝对时间, 网络 管理设备回复待同步基站时钟源请求响应消息 Ge tTime_Rep , ,并在所述时钟源 请求响应消息中包括所述时钟源基站的信息。
方式二、待同步基站不需要向 GW/EMS发送时钟源请求消息,而是接收由 EMS 主动发送的时钟源基站的信息。
步骤 22、 所述待同步基站根据所述时钟源基站的信息与所述时钟源基站进 行下行同步。 此步骤可参照本发明实施例一中的步骤 12。
步骤 23、 所述待同步基站获取绝对系统时间参考参数。
在实际应用中, 任何无线系统在控制信道消息中都会携带参考帧号 FN, 而 只有某些系统在控制信道消息中携带系统时间。 在本实施例中, 对于时间参数 在控制信道消息中是可选的系统, 网络管理设备要求时钟源基站在控制信道消 息中携带系统时间参数。 故时钟源基站在其控制信道消息中携带的绝对系统时 间参考参数包括: 系统时间参数 AIR_SYSTIME和参考帧号 FN。 待同步基站通 过读取时钟源基站的控制信道消息中的绝对系统时间参考参数, 得到时钟源 基站的系统时间参数 AIR-SYSTIME和参考帧号 FN。
步骤 24、 所述待同步基站根据所述绝对系统时间参考参数计算绝对系 统时间, 并利用所述绝对系统时间与所述时钟源基站进行系统时间同步。
在此步骤中, 所述待同步基站利用所述系统时间参数获得系统帧号, 再根据所述系统帧号、 所述参考帧号和所述系统时间参数获得所述绝对系 统时间。
具体计算流程如下:
步骤 241、 由所述系统时间参数获取系统帧号, 即由 AIR-SYSTIME获得 FN ByAi rTime , 其中计算公式为:
AIR_SYSTIME= (Y*y+M*m+D*d+H*h+M*m+S* s)
FNByAi rTime= ( AIR_SYSTIME*200 ) % OxFFFFFF
其中, Y、 M、 D、 H、 M、 S分别代表年、 月、 日、 小时、 分钟、 秒的权值, y、 m、 d、 h、 m、 s分别代表年、 月、 日、 小时、 分钟、 秒的实际值, FNByAi rTime 代表系统帧号, AIR-SYSTIME代表系统时间参数(y_m_d_h_m_s) , 常量 200是指 在 WiMAX空口协议 802. 16e中每秒通常设置为 200帧(帧长 5ms ),常量 OxFFFFFF 是因为 802. 16协议定义帧号长度是 3个字节, 其他通讯系统根据具体定义会有 所不同, 所述帧号包括 WiMAX系统中的所有帧号。
步骤 242、 根据所述系统帧号、 所述参考帧号和所述系统时间参数获得 所述绝对系统时间, 其中计算公式为:
mi l l i second = (FN- FNByAi rTime) *Ts TIME=AIR_ SYSTIME+ mi l l i second
其中, FN代表参考帧号, FNByAi rTime代表系统帧号, Ts代表时间常数(帧 长, WiMAX协议中一般设置为 5ms ), mi 1 1 i second代表相对时间, 单位为毫秒, TIME代表获得的绝对系统时间(y_m_d_h_m_s_ms) 。
在实际应用中, 由于参数传输或计算延时等原因绝对系统时间 TIME会比时 钟源基站的实时时间略晚, 当需要更高时间精确度时, 待同步基站可以在获得 的绝对系统时间 TIME的基础上再进行时间校准。 因此, 本实施例还可以包含步 骤 25以实现待同步基站与时钟源基站的实时时间同步, 但该步骤并不是本实施 例必需的。
步骤 25、 待同步基站获取实时绝对时间, 并利用所述实时绝对时间与所 述时钟源基站进行实时时间同步。
在此步骤中, 待同步基站再次读取所述时钟源基站的控制信道消息获取 实时帧号, 然后, 待同步基站根据所述绝对系统时间、 所述实时帧号和所 述参考帧号获得时钟源站的实时绝对时间。
具体公式为:
TIMErea l = TIME + (FNrea l - FN) *Ts
其中 TIME是步骤 24中已经获得的绝对系统时间(y_m_d_h_m_s_ms) , FNrea l 是再次读取时钟源站控制信道消息获取的实时帧号, FN是步骤 23中已经获取的 参考帧号, Ts是时间常数(帧长, WiMAX协议中一般设置为 5ms ), TIMErea l就 是时钟源站的实时绝对时间。
进而, 待同步基站利用所述实时绝对时间与所述时钟源基站进行实时 时间同步。
利用本发明实施例二的技术方案, 在没有安装 GPS星卡或者路由器和交 换机不支持 IEEE 1588V2协议的情况下, 待同步基站仍能从时钟源基站的控制 信道消息中解析并获取绝对系统时间参考参数, 包括系统时间参数 ( AIR-SYSTIME ) 和参考帧号 FN , 并根据所述绝对系统时间参考参数计算绝对 系统时间, 从而实现待同步基站与时钟源基站系统时间同步, 进一步的, 还可以再利用绝对系统时间进一步计算实时绝对时间, 做到待同步基站与时钟 源基站的实时时间同步, 从而提高了基站获取实时绝对时间的可靠性。
如图 3 所示, 本发明实施例三提供了一种实现时间同步的方法。 其中, 在 本发明实施例三中, 待同步基站从网络管理设备获取所述系统时间参数, 并 从所述时钟源基站的控制信道消息中获取所述参考帧号。 具体包括:
步骤 31、 待同步基站获取时钟源基站的信息。
此步骤可参照本发明实施例二中的步骤 21。
步骤 32、 所述待同步基站根据所述时钟源基站的信息与所述时钟源基站 进行下行同步。
此步骤可参照本发明实施例一中的步骤 12。
步骤 33、 待同步基站从时钟源基站获取参考帧号。
在本实施例中, 时钟源基站的控制信道消息只携带参考帧号, 故待同步基 站从时钟源基站的控制信道消息中只能获取参考帧号。
步骤 34、 待同步基站获取系统时间参数。
在本实施例中, 时钟源基站的空口控制信道消息不携带系统时间参数, 故 待同步基站无法直接从时钟源基站的控制信道消息中获取系统时间参数, 而只 能从网络管理设备中获取系统时间参数, 具体包括:
待同步基站向网络管理设备, 如: GW或 EMS或 ClockServer (时钟服务器) 发送参考时间请求消息 GetTime_Reci,所述网络管理设备回复待同步基站参考时 间请求响应消息 GetTime_Rep, 并在所述参考时间请求响应消息中携带系统时 间参数。
步骤 35、 待同步基站根据绝对系统时间参考参数计算绝对系统时间, 并 利用所述绝对系统时间与所述时钟源基站进行系统时间同步。
所述绝对系统时间参考参数包括 系统时间参数 NET-SYSTIME和参考帧 号 FN。 待同步基站利用所述系统时间参数获得系统帧号, 再根据所述系统 帧号、 所述参考帧号和所述系统时间参数获得所述绝对系统时间。
具体计算流程如下:
步骤 351、 由所述系统时间参数获取系统帧号, 即由 NET_SYSTIME 获取 NET_SYSTIME= (Y*y+M*m+D*d+H*h+M*m+S* s)
FNByNe tTime= ( NET_SYSTIME*200 ) % OxFFFFFF
其中, Y、 M、 D、 H、 M、 S分别代表年、 月、 日、 小时、 分钟、 秒的权值, y、 m、 d、 h、 m、 s分别代表年、 月、 日、 小时、 分钟、 秒的实际值, FNByNe tTime 代表系统帧号, NET-SYSTIME代表系统时间参数(y_m_d_h_m_s) , 常量 200是指 在 WiMAX空口协议 802. 16e中每秒通常设置为 200帧(帧长 5ms ),常量 OxFFFFFF 是因为 WiMAX空口协议 802. 16中定义帧号长度是 3个字节, 其他通讯系统根据 具体协议规定会有所不同, 所述帧号包括 WiMAX系统中的所有帧号。
步骤 352、 根据所述系统帧号、 所述参考帧号和所述系统时间参数获得 所述绝对系统时间, 其中计算公式为:
Mi l l i second= (FN- FNByNe tTime) *Ts
TIME= NET-SYSTIME + mi l l i second
其中, FN代表参考帧号, FNByNe tTime代表系统帧号, Ts代表时间常数(帧 长, WiMAX基站一般设置为 5ms ), mi l l i second代表相对时间,单位为毫秒, TIME 代表获得的绝对系统时间(y_m_d_h_m_s_ms)。
在实际应用中, 由于参数传输或计算延时等原因绝对系统时间 TIME会比时 钟源基站的实时时间略晚, 当需要更高时间精确度时, 待同步基站可以在获得 的绝对系统时间 TIME的基础上再进行时间校准。 因此, 可选的, 本实施例还可 以包含步骤 36以实现待同步基站与时钟源基站的实时时间同步, 但该步骤并不 是本实施例必需的。
步骤 36、待同步基站进一步计算实时绝对时间,并利用所述实时绝对时间 与所述时钟源基站进行实时时间同步。
在此步骤中, 待同步基站再次读取所述时钟源基站的控制信道消息获取 实时帧号, 然后, 待同步基站根据所述绝对系统时间、 所述实时帧号和所 述参考帧号获得时钟源站的实时绝对时间。
具体公式为:
TIMErea l = TIME + (FNrea l - FN) *Ts
其中 TIME是已经获得的绝对系统时间(y_m_d_h_m_s_ms), FNrea l是再次读 取时钟源站控制信道消息获取的实时帧号, FN是计算 TIME时已经获取的参考帧 号, Ts是时间常数(帧长, WiMAX协议中一般设置为 5ms ), TIMErea l就是时钟 源站的实时绝对时间。
进而, 待同步基站利用所述实时绝对时间与所述时钟源基站进行实时 时间同步。
利用本发明实施例三的技术方案, 在时钟源基站的控制信道消息中不携 带系统时间参数的情况下,待同步基站从 GW/EMS/ClockServer获取系统时间参 数, 再从时钟源基站的控制信道消息中解析并获取参考帧号 FN , 并根据所述绝 对系统时间参考参数计算绝对系统时间, 从而实现待同步基站与时钟源基站 系统时间同步, 进一步的, 还可以利用所述绝对系统时间获得实时绝对时间, 做到待同步基站与时钟源基站的实时时间同步, 从而提高了基站获取实时绝对 时间的可靠性。
如图 4 所示, 本发明实施例四提供了一种实现时间同步的方法。 在本发明 实施例四中, 待同步基站通过网络管理设备从所述时钟源基站获取所述系 统时间参数, 并从所述时钟源基站的控制信道消息中获取所述参考帧号。 具体包括:
步骤 41、 待同步基站获取时钟源基站的信息。
此步骤可参照本发明实施例二中的步骤 21。
步骤 42、 所述待同步基站根据所述时钟源基站的信息与所述时钟源基站 进行下行同步。
此步骤可参照本发明实施例一中的步骤 12。
步骤 43、 待同步基站从时钟源基站获取参考帧号。
在本实施例中, 由于时钟源基站的控制信道消息只携带参考帧号, 故待同 步基站从时钟源基站的控制信道消息中只能获取参考帧号。
步骤 44、 待同步基站获取系统时间参数。
在本实施例中, 时钟源基站的控制信道消息无法携带系统时间参数(如有 的通讯系统控制信道消息不支持时间参数), 故待同步基站无法直接从时钟源基 站的控制信道消息获取系统时间参数, 而只能通过网络管理设备从所述时钟 源基站获取所述系统时间参数, 具体包括:
待同步基站通过网络管理设备,如 GW或 EMS或 ClockServer (时钟服务器) ) 向时钟源基站发送参考时间请求消息 GetTime_Reci,然后时钟源基站通过所述网 络管理设备回复参考时间请求响应消息 GetTime_Rep , 并在所述参考时间请求 响应消息中包括系统时间参数。
步骤 45、所述待同步基站根据所述绝对系统时间参考参数计算绝对系统 时间, 并利用所述绝对系统时间与所述时钟源基站进行系统时间同步。
所述绝对系统时间参考参数包括 系统时间参数 NET-SYSTIME和参考帧 号 FN。 待同步基站利用所述系统时间参数获得系统帧号, 再根据所述系统 帧号、 所述参考帧号和所述系统时间参数获得所述绝对系统时间。
具体计算流程如下:
步骤 451、 由所述系统时间参数获取系统帧号, 即由 NET_SYSTIME 获取 FNByNetTime , 其中计算公式为:
NET_SYSTIME= (Y*y+M*m+D*d+H*h+M*m+S* s)
FNByNetTime= ( NET_SYSTIME*200 ) % OxFFFFFF
其中, Y、 M、 D、 H、 M、 S分别代表年、 月、 日、 小时、 分钟、 秒的权值, y、 m、 d、 h、 m、 s分别代表年、 月、 日、 小时、 分钟、 秒的实际值, FNByNetTime 代表系统帧号, NET-SYSTIME代表系统时间参数(y_m_d_h_m_s) , 常量 200是指 在 WiMAX空口协议 802. 16e中每秒通常设置为 200帧(帧长 5ms ),常量 OxFFFFFF 是因为 WiMAX空口协议 802. 16中定义帧号长度是 3个字节, 其他通讯系统根据 具体协议规定会有所不同, 所述帧号包括 WiMAX系统中所有帧号。
步骤 452、 根据所述系统帧号、 所述参考帧号和所述系统时间参数获得 所述绝对系统时间, 其中计算公式为:
Mi l l i second= (FN- FNByNetTime) *Ts
TIME= NET-SYSTIME + mi l l i second
其中, FN代表参考帧号, FNByNetTime代表系统帧号, Ts代表时间常数(帧 长, WiMAX基站一般设置为 5ms ), mi l l i second代表相对时间,单位为毫秒, TIME 代表获得的绝对系统时间(y_m_d_h_m_s_ms)。 在实际应用中, 由于参数传输或计算延时等原因绝对系统时间 TIME会比时 钟源基站的实时时间略晚, 当需要更高时间精确度时, 待同步基站可以在获得 的绝对系统时间 TIME的基础上再进行时间校准。 因此, 本实施例还可以包含步 骤 46以实现待同步基站与时钟源基站的实时时间同步, 但该步骤并不是本实施 例必需的。
步骤 46、待同步基站进一步计算实时绝对时间,并利用所述实时绝对时间 与所述时钟源基站进行实时时间同步。
在此步骤中, 待同步基站再次读取所述时钟源基站的控制信道消息获 取实时帧号, 然后, 待同步基站根据所述绝对系统时间、 所述实时帧号和 所述参考帧号获得时钟源站的实时绝对时间。
具体公式为:
TIMEreal = TIME + (FNreal - FN) *Ts
其中 TIME是已经获得的绝对系统时间(y_m_d_h_m_s_ms), FNreal是再次读 取时钟源站控制信道消息获取的实时帧号, FN是计算 TIME时已经获取的参考帧 号, Ts是时间常数(帧长, WiMAX协议中一般设置为 5ms ), TIMEreal就是时钟 源站的实时绝对时间。
进而, 待同步基站利用所述实时绝对时间与所述时钟源基站进行实时 时间同步。
利用本发明实施例四的技术方案, 在时钟源基站的控制信道消息中不携 带系统时间参数的情况下, 待同步基站通过 GW/EMS/ClockServer由所述时钟 源基站获取所述系统时间参数, 再从时钟源基站的控制信道消息中解析并获 取参考帧号 FN, 并根据所述绝对系统时间参考参数计算绝对系统时间,从而实 现待同步基站与时钟源基站系统时间同步, 还可以再进一步利用所述绝对系 统时间获得所述实时绝对时间, 做到与时钟源基站的实时时间同步, 从而提高 了基站获取实时绝对时间的可靠性。
如图 5所示, 本发明实施例五的基站包括: 信息获取单元 51 , 用于获取 时钟源基站的信息; 下行同步单元 52 , 用于根据所述时钟源基站的信息与所 述时钟源基站进行下行同步; 参数获取单元 53, 用于获取绝对系统时间参考 参数; 第一时间同步单元 54 , 用于根据所述绝对系统时间参考参数计算绝对 系统时间, 并利用所述绝对系统时间进行系统时间同步。
在本发明实施例中, 所述时钟源基站是指有 GPS星卡或 IEEE 1588V2等时 钟源, 可以获得绝对时间的基站。 其中, 所述时钟源基站的信息可以包括时钟 源基站的名称, 或者编号等信息。
其中, 如方法实施例中的描述, 所述信息获取单元可通过至少两种方 式获取绝对系统时间参考参数。 相应的, 所述信息获取单元 51具体可包括: 请求发送模块, 用于向网络管理设备发送时钟源请求消息; 消息接收模块, 用 于接收所述网络管理设备发送的时钟源请求响应消息, 在所述时钟源请求响应 消息中包括所述时钟源基站的信息。 或者, 所述信息获取单元 51可具体用 于, 接收由所述网络管理设备发送的时钟源基站的信息。
对于 WiMAX系统, 所述下行同步单元 52可具体用于,扫描该指定时钟源基 站的下行同步信道, 来跟时钟源基站做到帧对齐, 再读取所述时钟源基站的控 制信道消息中的参考帧号, 从而, 待同步基站和时钟源基站可以做到筒单的帧 号同步。
如方法实施例中的描述, 所述绝对系统时间参考参数可包括: 系统时间 参数和参考帧号。 因此, 所述参数获取单元 53可具体用于读取所述时钟源 基站的控制信道消息, 获取所述系统时间参数和参考帧号。
或者, 所述参数获取单元 53可具体用于由网络管理设备获取所述系 统时间参数, 读取所述时钟源基站的控制信道消息获取所述参考帧号。 此时, 所述参数获取单元 53可包括: 消息发送模块, 用于向所述网络管 理设备发送参考时间请求消息; 消息接收模块, 用于向接收所述网络管 理设备发送的参考时间请求响应消息, 在所述参考时间请求响应消息中 包括所述系统时间参数。
或者, 所述参数获取单元 53可具体用于通过网络管理设备由所述时 钟源基站获取所述系统时间参数, 读取所述时钟源基站的控制信道消, 获取所述参考帧号。 此时, 所述参数获取单元 53可包括: 消息发送模块, 用于通过所述网络管理设备向所述时钟源基站发送参考时间请求;肖 , ¾; 肖 , 接收模块, 用于接收所述时钟源基站通过所述网络管理设备发送的 参考时间请求响应消息, 在所述参考时间请求响应消息中包括所述系统 时间参数。
其中,所述参数获取单元 53的工作原理可参照前述方法实施例中的描述。 其中, 如图 6所示, 所述第一时间同步单元 54包括: 第一计算模块 541 , 用于利用所述系统时间参数获得系统帧号; 第二计算模块 542 , 用于根据 所述系统帧号、 所述系统时间参数和所述参考帧号获得所述绝对系统时 间; 时间同步模块 543, 用于利用所述绝对系统时间与所述时钟源基站进 行系统时间同步。
其中, 所述时间同步单元 54的工作原理可参照前述方法实施例中的描 述。
如图 7所示,在本发明实施例中,由于参数传输或计算延时等原因 TIME 会比时钟源基站实时时间略晚,需要更高时间精确度时,所述基站还可包括: 实时帧号获取单元 55 , 用于读取所述时钟源基站的控制信道消息获取实时 帧号; 第二时间同步单元 56 , 用于根据所述绝对系统时间、 实时帧号和参 考帧号获得时钟源站的实时绝对时间, 并利用所述实时绝对时间与所述 时钟源基站进行实时时间同步。
因而, 利用本发明实施例五的基站, 在没有安装 GPS星卡或者路由器和 交换机不支持 IEEE 1588V2 协议的情况下, 仍能获取绝对系统时间参考参数, 并根据绝对系统时间参考参数计算绝对系统时间,从而实现待同步基站与时钟 源基站系统时间同步, 还可以再才艮据绝对系统时间进一步计算实时绝对时间, 从而做到与时钟源基站的实时时间同步。 因此, 利用本发明实施例五的基站, 提高了基站获取实时绝对时间的可靠性。
综上所述, 本发明实施例提供的实现时间同步的方法及基站, 首先获取时 钟源基站的信息, 而后根据所述时钟源基站的信息与所述时钟源基站进行下行 同步, 再获取绝对系统时间参考参数, 进而根据所述绝对系统时间参考参数计 算绝对系统时间, 并利用所述绝对系统时间与所述时钟源基站进行系统时间同 步。 因此, 本发明实施例提供的实现时间同步的方法及基站提高了待同步基站 通信的可靠性。
以上所述, 仅为本发明的具体实施方式, 但本发明的保护范围并不局限于 此, 任何熟悉本技术领域的技术人员在本发明揭露的技术范围内, 可轻易想到 变化或替换, 都应涵盖在本发明的保护范围之内。 因此, 本发明的保护范围应 以所述权利要求的保护范围为准。

Claims

权 利 要 求
1、 一种实现时间同步方法, 其特征在于, 包括:
获取时钟源基站的信息;
根据所述时钟源基站的信息与所述时钟源基站进行下行同步; 获取绝对系统时间参考参数;
根据所述绝对系统时间参考参数计算绝对系统时间, 并利用所述绝 对系统时间与所述时钟源基站进行系统时间同步。
2、 根据权利要求 1所述的实现时间同步方法, 其特征在于, 所述获 取时钟源基站的信息包括:
向网络管理设备发送时钟源请求消息, 接收所述网络管理设备发送 的时钟源请求响应消息, 其中所述时钟源请求响应消息中包括时钟源基 站的信息; 或
接收由所述网络管理设备发送的时钟源基站的信息。
3、 根据权利要求 1所述的实现时间同步方法, 其特征在于, 所述绝 对系统时间参考参数包括: 系统时间参数和参考帧号; 所述获取绝对系 统时间参考参数包括:
读取所述时钟源基站的控制信道消息获取所述系统时间参数和参考 帧号; 或
从网络管理设备获取所述系统时间参数, 读取所述时钟源基站的控 制信道消息获取所述参考帧号; 或
通过网络管理设备从所述时钟源基站获取所述系统时间参数, 读取 所述时钟源基站的控制信道消息获取所述参考帧号。
4、 根据权利要求 3所述的实现时间同步方法, 其特征在于, 所述从 网络管理设备获取所述系统时间参数包括:
向所述网络管理设备发送参考时间请求消息;
接收所述网络管理设备发送的参考时间请求响应消息, 其中, 所述 参考时间请求响应消息中包括所述系统时间参数。
5、 根据权利要求 3所述的实现时间同步方法, 其特征在于, 所述通 过网络管理设备从所述时钟源基站获取所述系统时间参数包括: 通过所述网络管理设备向所述时钟源基站发送参考时间请求消息; 接收所述时钟源基站通过所述网络管理设备发送的参考时间请求响 应消息, 其中, 所述参考时间请求响应消息中包括所述系统时间参数。
6、 根据权利要求 1所述的实现时间同步方法, 其特征在于, 所述绝 对系统时间参考参数包括: 系统时间参数和参考帧号; 所述根据所述绝 对系统时间参考参数计算绝对系统时间包括:
利用所述系统时间参数获得系统帧号;
根据所述系统帧号、 所述系统时间参数和所述参考帧号获得所述绝 对系统时间。
7、 根据权利要求 6所述的实现时间同步方法, 其特征在于, 在所述 根据所述绝对系统时间参考参数计算绝对系统时间, 并利用所述绝对系 统时间与所述时钟源基站进行系统时间同步之后, 所述方法还包括: 读取所述时钟源基站的控制信道消息获取实时帧号;
根据所述绝对系统时间、 所述实时帧号和所述参考帧号获得时钟源 站的实时绝对时间, 并利用所述实时绝对时间与所述时钟源基站进行实 时时间同步。
8、 一种基站, 其特征在于, 包括:
信息获取单元, 用于获取时钟源基站的信息;
下行同步单元, 用于根据所述时钟源基站的信息与所述时钟源基站 进行下行同步;
参数获取单元, 用于获取绝对系统时间参考参数;
第一时间同步单元, 用于根据所述绝对系统时间参考参数计算绝对 系统时间, 并利用所述绝对系统时间与所述时钟源基站进行系统时间同 步。
9、 根据权利要求 8所述的基站, 其特征在于, 所述信息获取单元包 括:
请求发送模块, 用于向网络管理设备发送时钟源请求消息; 消息接收模块, 用于接收所述网络管理设备发送的时钟源请求响应 消息, 其中, 所述时钟源请求响应消息中包括时钟源基站的信息。
1 0、 根据权利要求 8所述的基站, 其特征在于, 所述信息获取单元 具体用于接收由网络管理设备发送的时钟源基站的信息。
1 1、 根据权利要求 8所述的基站, 其特征在于, 所述绝对系统时间 参考参数包括: 系统时间参数和参考帧号;
所述参数获取单元具体用于读取所述时钟源基站的控制信道消息获
Figure imgf000019_0001
数, 读取所述时钟源基站的控制信道消息获取所述参考帧号; 或 取所述系统时间参数, 读取所述时钟源基站的控制信道消息获取所述参 考帧号。
1 2、 根据权利要求 1 1所述的基站, 其特征在于, 所述参数获取单元 包括:
消息发送模块, 用于向所述网络管理设备发送参考时间请求消息; 消息接收模块, 用于接收所述网络管理设备发送的参考时间请求响 应消息, 其中, 所述参考时间请求响应消息中包括所述系统时间参数。
1 3、 根据权利要求 1 1所述的基站, 其特征在于, 所述参数获取单元 包括:
消息发送模块, 用于通过所述网络管理设备向所述时钟源基站发送 参考时间请求消息;
消息接收模块, 用于接收所述时钟源基站通过所述网络管理设备发 送的参考时间请求响应消息, 其中, 所述参考时间请求响应消息中包括 所述系统时间参数。
14、 根据权利要求 8所述的基站, 其特征在于, 所述绝对系统时间 参考参数包括: 系统时间参数和参考帧号;
所述第一时间同步单元包括: 第一计算模块, 用于利用所述系统时间参数获得系统帧号; 第二计算模块, 用于根据所述系统帧号、 所述系统时间参数和所述 参考帧号获得所述绝对系统时间;
时间同步模块, 用于利用所述绝对系统时间与所述时钟源基站进行 系统时间同步。
15、 根据权利要求 14所述的基站, 其特征在于, 所述基站还包括: 实时帧号获取单元, 用于读取所述时钟源基站的控制信道消息获取实时 帧号;
第二时间同步单元, 用于根据所述绝对系统时间、 所述实时帧号和所述 参考帧号获得时钟源站的实时绝对时间, 并利用所述实时绝对时间与所述 时钟源基站进行实时时间同步。
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