KR20080065107A - Apparatus and method for synchronizing clock between bsc and bts in mobile communication system - Google Patents

Abstract

An apparatus for synchronizing clock between a base station and a control station in mobile communication system is provided to generate each system clock and maintain synchronization state by recovering clock in a connecting link between the base station and the control station or generating clock form a local oscillator when abnormal generating of GPS clock receiving. An apparatus for synchronizing clock between a base station and a control station in mobile communication system includes a transmitting and receiving unit(304) transmits and receives a data by a connecting link to the base station, a controlling unit(300) checks judgment of availability for transmitting a GPS clock and transmitting the data by the connecting link, and a generating clock unit(308) recovering the clock received the data from the controlling unit generates a system clock, when receiving the data from the link.

Description

Method and apparatus for synchronizing clock between base station and control station in mobile communication system {APPARATUS AND METHOD FOR SYNCHRONIZING CLOCK BETWEEN BSC AND BTS IN MOBILE COMMUNICATION SYSTEM}

1 is a diagram illustrating a clock synchronization method between a base station and a control station in a mobile communication system according to the prior art;

2 is a block diagram of a base station in a mobile communication system according to the present invention;

3 is a block diagram of a control station in a mobile communication system according to the present invention;

4 is a diagram illustrating a clock synchronization procedure of a base station in a mobile communication system according to an embodiment of the present invention;

5 is a diagram illustrating a clock synchronization procedure of a control station in a mobile communication system according to an embodiment of the present invention;

6 is a diagram illustrating a clock synchronization method using a GPS module of each of a base station and a control station in a mobile communication system according to an embodiment of the present invention;

7 is a diagram illustrating a clock synchronization method using another network in a mobile communication system according to an embodiment of the present invention;

8 is a diagram illustrating a clock synchronization method using a GPS module of a base station in a mobile communication system according to an embodiment of the present invention; and

9 illustrates a clock synchronization method using a local oscillator in a mobile communication system according to an embodiment of the present invention.

The present invention relates to a method and apparatus for clock synchronization between a base station and a control station in a mobile communication system. In particular, the present invention relates to a clock synchronization between a base station and a control station even when an error occurs in GPS clock reception using various clock synchronization methods. A method and apparatus are disclosed.

In general, each system clock used in the base station and the control station for the normal data transmission and reception between a base station controller (hereinafter referred to as a control station) and a base transceiver station constituting a mobile communication system clock) must be synchronized. In particular, when transmitting and receiving E1 / T1 data in the base station and the control station, all transmission and reception data must be synchronized to restore the data received at each of the base station and the control station.

Therefore, in the mobile communication system according to the prior art, the clock is synchronized between the base station and the control station using GPS.

1 illustrates a clock synchronization method between a base station and a control station in a mobile communication system according to the prior art.

As shown in FIG. 1, conventionally, each of the base station 110 and the control station 100 receives GPS clocks from the GPS satellites 104 and 112 by using a Global Positioning System (GPS) module. Generated the system clock of. Here, the system clock of each of the base station 110 and the control station 100 generated using the GPS clock automatically maintains a clock synchronization state.

However, when using the GPS-based method as described above, if a problem occurs in the GPS module of the base station or the control station, that is, the GPS clock receiver, the base station and the control station have a problem that the clock synchronization state is lost. In addition, when the base station or the control station implements a system that does not use the GPS clock, or when data transmission and reception between the base station and the control station must pass through another network such as a time division multiplexing (TDM) network, the above-described method using GPS There is a problem in that clock synchronization cannot be achieved.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a clock synchronization method and apparatus between a base station and a control station in a mobile communication system.

Another object of the present invention is to provide a method and apparatus for synchronizing clock synchronization between a base station and a control station in various structures of a mobile communication system.

Another object of the present invention is to provide a method and apparatus for synchronizing clocks using a link between the base station and a control station in a mobile communication system.

It is still another object of the present invention to provide a method and apparatus for synchronizing a clock between a base station and a control station using a clock generated from a local oscillator in a control station of a mobile communication system.

According to a first aspect of the present invention for achieving the above objects, a method for operating a control station for clock synchronization between a base station and a control station in a mobile communication system, the method for checking whether the GPS (Global Positioning System) clock reception is possible And checking whether there is an input link when receiving the GPS clock, and generating a system clock by restoring a clock from data received on the input link when the input link exists. It is characterized by.

According to a second aspect of the present invention for achieving the above object, the operation method of the base station for clock synchronization between the base station and the control station in the mobile communication system, the process of checking whether the GPS (Global Positioning System) clock reception is possible And when the GPS clock reception is impossible, generating a system clock by restoring a clock from data received on an input link.

According to a third aspect of the present invention for achieving the above objects, a control station apparatus for clock synchronization between a base station and a control station in a mobile communication system, the transceiver unit for transmitting and receiving data through a connection link with the base station, GPS (Global Positioning System) A control unit which checks whether clock reception is possible and whether data is received through the connection link, and when data is received through the link, a clock is received from the received data under control of the control unit. And a clock generator for restoring the system clock.

According to a fourth aspect of the present invention for achieving the above objects, a base station apparatus for clock synchronization between a base station and a control station in a mobile communication system, the transceiver unit for transmitting and receiving data through a connection link with the control station, GPS (Global Positioning System) A control unit which checks whether clock reception is possible and whether data is received through the connection link, and when data is received through the link, a clock is received from the received data under control of the control unit. And a clock generator for restoring the system clock.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, a method and apparatus for synchronizing clock synchronization between a base station and a control station using a GPS clock, a link between a base station and a control station, or a local oscillator of the control station in various structures of a mobile communication system will be described. .

2 is a block diagram of a base station in a mobile communication system according to the present invention. In this case, the base station includes a control unit 200, a GPS module 202, an E1 / T1 transceiver 204, a link selector 206, a clock generator, and a synchronizer 208.

Referring to FIG. 2, first, the control unit 200 controls and processes the overall operation of the base station, and according to the present invention, the state of the current system, that is, whether the GPS clock is received and the transmission / reception link state with the control station. By judging, the clock generation method that can set the synchronous state of the normal system clock is determined. In other words, when the GPS clock is normally received from the GPS module 202, the controller 200 determines to generate a system clock by using the GPS clock, and then generates and clocks the received GPS clock. Output to base 208. On the other hand, when the GPS clock is not normally received from the GPS module 202 or when the GPS module 202 does not exist, the controller 200 disconnects a link input through the E1 / T1 transceiver 204. After deciding to generate a system clock by using the link selector 206, a normal link is selected among the input links to provide data received from the link to the clock generator and synchronizer 208. . In addition, the controller 200 controls and processes a function for transmitting data through a link connected to the control station by synchronizing the transmission data with the generated system clock when transmitting data to the control station.

The GPS module 202 receives a GPS clock from a GPS satellite and provides the GPS clock to the controller 200. Here, the GPS module 202 may or may not be included in the base station according to the system state of the base station.

The E1 / T1 transceiver 204 transmits and receives data with the control station using the E1 / T1 standard. In particular, the E1 / T1 transceiver 204 provides a link input to the link selector 206 under the control of the controller 200. Here, the input link may be a link directly connected to the control station or may be a link connected through another network.

The link selector 206 examines a state of a link input from the E1 / T1 transceiver 204 under control of the controller 200, selects a link in a normal state, and selects data received from the selected link. The clock generation and synchronization unit 208 is provided.

The clock generation and synchronization unit 208 generates a system clock of the base station and synchronizes the generated system clock with the system clock of the control station. Particularly, according to the present invention, when the GPS clock is received from the controller 200, the clock generator and synchronizer 208 generates a system clock of the base station using the received GPS clock, and the controller ( When data of a specific link is input from 200, the clock is restored from the input data to generate and synchronize a system clock with a clock generated through a phase locked loop (PLL). When the system clock is generated using the GPS clock, the system clocks of the base station and the control station are automatically synchronized.

3 is a block diagram of a control station in a mobile communication system according to the present invention. In this case, the control station includes a control unit 300, a GPS module 302, an E1 / T1 transceiver 304, a link selector 306, and a clock distributor 308.

Referring to FIG. 3, first, the control unit 300 controls and processes the overall operation of the control station, and according to the present invention, the state of the current system, that is, whether the GPS clock is received and the transmission / reception link state with the base station By judging, the clock generation method that can set the synchronous state of the normal system clock is determined. In other words, when the GPS clock is normally received from the GPS module 302 in the control station, the controller 300 determines to generate a system clock using the GPS clock, and then converts the received GPS clock into the clock. Output to the distribution unit 308. On the other hand, when the GPS clock is not normally received from the GPS module 302 or when the GPS module 302 does not exist, the controller 300 connects a link input through the E1 / T1 transceiver 304. After determining to generate a system clock using the link selector 206, the link selector 206 selects a normal link among the input links to provide data received from the link to the clock distributor 208. Here, when the control station is not connected to another network or when the GPS clock is not received, the control unit 300 may determine to generate a system clock by itself and notify the clock distribution unit 308. When the system clock is generated by the clock distribution unit 308 and the data is transmitted to the base station, the controller 300 synchronizes the transmission data with the generated system clock to transmit the data through a link connected to the base station. Control and process the functions for transmission.

The GPS module 302 receives a GPS clock from a GPS satellite and provides the GPS clock to the controller 300. Here, the GPS module 302 may or may not be included in the control station according to the system state of the control station.

The E1 / T1 transceiver 304 plays a role of transmitting and receiving data with the base station using the E1 / T1 standard. In particular, the E1 / T1 transceiver 304 provides a link input to the link selector 306 under the control of the controller 300. Here, the input link may be a link directly connected to the base station or may be a link connected through another network.

The link selector 306 checks the state of the link input from the E1 / T1 transceiver 304 under the control of the controller 300, selects a link in a normal state, and selects data received from the selected link. The clock distribution unit 208 is provided.

The clock distributor 308 generates a system clock of the control station and synchronizes the generated system clock with the system clock of the base station. In particular, according to the present invention, when the GPS clock is received from the control unit 300, the clock distribution unit 208 generates the system clock of the control station itself using the received GPS clock, and the control unit 300 When data of a specific link is inputted from), the clock is restored from the data to generate and synchronize a system clock with a clock generated through a phase locked loop (PLL). When the system clock is generated using the GPS clock, the system clocks of the base station and the control station are automatically synchronized. In addition, when the link is directly received from the base station, the clock recovered from the link may be a clock synchronized with the GPS clock received by the base station using its GPS module. On the other hand, the clock distribution unit 308 generates a system clock to be used in the control station using a local oscillator (local oscillator) when a signal indicating the generation of its own clock from the control unit 300, Generates a clock used for the connection link with the base station.

4 illustrates a clock synchronization procedure of a base station in a mobile communication system according to an embodiment of the present invention.

Referring to FIG. 4, the base station checks whether a GPS module exists in the base station in step 401, and if the GPS module exists, proceeds to step 403 to check whether the GPS module operates normally.

When the GPS module operates normally, the base station receives a GPS clock using the GPS module in step 405 and proceeds to step 407 to generate a system clock used in the base station based on the received GPS clock. After that, the algorithm according to the present invention is terminated.

In contrast, when the GPS module does not exist in the base station in step 401 or when the GPS module does not operate normally in step 403, the base station checks the state of the link input in step 409, and then proceeds to step 411. The link checked in the normal state is selected from the input links. In step 413, the base station restores a clock from data received on the selected link to generate a system clock. Here, the link is a link directly connecting the base station and the control station, and the clock recovered from the link may be a clock synchronized with a system clock generated by a local oscillator at the control station itself. In addition, the link is a link input through another network such as a TDM network, and the restored clock may be a clock dependent on the other network.

The base station then terminates the algorithm according to the invention.

5 illustrates a clock synchronization procedure of a control station in a mobile communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the control station checks whether a GPS module exists in the control station in step 501, and if the GPS module exists, proceeds to step 503 to check whether the GPS module operates normally.

When the GPS module operates normally, the control station receives a GPS clock using the GPS module in step 505 and proceeds to step 507 to use a system clock used in the control station based on the received GPS clock. After generating, the algorithm according to the present invention is terminated.

In contrast, when the GPS module does not exist in the control station in step 501 or when the GPS module does not operate normally in step 503, the control station checks whether there is a link input in step 509. When the input link exists, the control station checks the state of the input links in step 511 and selects a link in a normal state. In step 513, the control station recovers a clock from data received on the selected link to generate a system clock. Here, the link is a link directly connecting the control station and the base station, and the clock recovered from the link may be a clock synchronized with the GPS clock of the base station. In addition, the link is a link input through another network such as a TDM network, and the restored clock may be a clock dependent on the other network. The control station then terminates the algorithm according to the invention.

When the input link does not exist, the control station proceeds to step 515 to generate a system clock using a local oscillator in the control station, and generates a clock used for the connection link with the base station, and then the present invention. Terminate the algorithm according to.

Next, a method of synchronizing a clock between the base station and the control station according to the structure in the mobile communication system will be described.

First, a clock synchronization method in a structure in which the base station and the control station each have a GPS module will be described with reference to FIG. 6.

As shown in FIG. 6, when the base station 610 and the control station 600 each have a GPS module, the control station 600 and the base station 610 are connected to the GPS satellites 604 and 612. A GPS clock is received to generate a system clock used in each system using the received GPS clock. Here, since the control station 600 and the base station 610 generates a system clock synchronized with the GPS clock, the system clocks of the control station 600 and the base station 610 are automatically synchronized.

Next, a clock synchronization method in a structure in which another network exists between the base station and the control station will be described with reference to FIG. 7. It is assumed here that neither the base station nor the control station can receive a GPS clock.

As illustrated in FIG. 7, data transmission is not directly performed between the base stations 720 and 730 and the control station 700, and the base station 720 is connected to another network, for example, a TDM transmission network 710. When data transmission is performed between the 730 and the control station 700, the base station 720, 730 and the control station 700 restores a clock from the data received from the TDM transmission network 710 to restore the respective system clock. Create At this time, the base station 720, 730 and the control station 700 selects a link in a normal state among the input links to restore the clock, and the system clocks of the base station 720, 730 and the control station 700 are It is synchronized to the clock recovered from the data of the link.

Next, referring to FIG. 8, a clock synchronization method in a structure in which another network does not exist between the base station and the control station and the GPS base station can be received by the base station will be described.

As shown in FIG. 8, when there is no other network between the base stations 820 and 830 and the control station 700, each base station 820 and 830 is provided with a GPS module to receive a GPS clock. The base station 820, 830 generates a system clock used in the system using the received GPS clock and synchronizes the data to be transmitted to the control station 800 with the GPS clock to link the data. Send it through. Accordingly, the control station 800 restores the clock from the data received through the link in the normal state of the connection link with the base station (820, 830), and then the control station 800 to the clock generated through the PLL. Create a system clock for your system. Thus, the system clock of the control station 800 is synchronized with the GPS clocks of the base stations 820 and 830.

Lastly, referring to FIG. 9, a clock synchronization scheme in a structure in which no other network exists between the base station and the control station and where both the base station and the control station cannot receive a GPS clock will be described.

As shown in FIG. 9, when the base stations 910 and 920 and the control station 900 are not connected to other networks and GPS clock reception is impossible, the control station 900 uses the local oscillator to control the control. A system clock used in the station 900 and a clock used for a link connected to the base stations 910 and 920 are generated. Accordingly, the base stations 910 and 920 recover their clocks from the data received on the link connected to the control station 900 to generate their system clocks. Thus, the system clocks of the base stations 910, 920 and control station 900 are synchronized to the local oscillator clock in the control station 900. Here, the clock synchronization method as shown in FIG. 9 may be used for testing the base station and the control station in a state in which the GPS clock cannot be received or there is no connection with the other network at the pre-shipment stage after system production. will be.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, according to the present invention, a GPS clock, a link between a base station and a control station, or a clock oscillation between the base station and the control station is matched by using a local oscillator of the control station in various structures of the mobile communication system, thereby failing to receive a GPS clock. In this case, the system clocks can be generated and the clock synchronization state can be generated by using the clocks generated in the connection link between the base station and the control station or the clocks generated by the local oscillator. In addition, it is possible to configure the system in a form suitable for the required network without changing the hardware.

Claims (21)

A method of operating a control station for clock synchronization between a base station and a control station in a mobile communication system, Checking whether the GPS (Global Positioning System) clock reception is possible; When it is impossible to receive the GPS clock, checking whether an input link exists; And generating a system clock by restoring a clock from data received at an input link when the input link exists. The method of claim 1, And when the GPS clock is available, generating a system clock based on the received GPS clock. The method of claim 1, And generating a system clock based on a clock generated by a local oscillator provided in the control station when the input link does not exist. The method of claim 3, wherein Generating a clock used in a link connected with a base station based on the clock generated by the local oscillator. The method of claim 1, Generating a system clock from the data received on the link, Selecting a link in a normal state by checking a state of input links; Restoring a clock from data received on the selected link; And generating a system clock using the clock generated by the restored clock passing through the phase locked loop. The method of claim 1, The input link is one of a link directly connected to the base station or a link connected to the base station through another network. The method of claim 1, And a system clock generated from the input link data is synchronized with a GPS clock of the base station when the input link is a link directly connected to the base station. The method of claim 1, And the system clock generated from the input link data is synchronized to a clock of the other network when the input link is a link connected to a base station through another network. A method of operating a base station for clock synchronization between a base station and a control station in a mobile communication system, Checking whether the GPS (Global Positioning System) clock reception is possible; Restoring a clock from data received on an input link when the GPS clock is not received, thereby generating a system clock. The method of claim 9, And when the GPS clock is available, generating a system clock based on the received GPS clock. The method of claim 9, Generating a system clock from the data received on the link, Selecting a link in a normal state by checking a state of input links; Restoring a clock from data received on the selected link; And generating a system clock using the clock generated by the restored clock passing through the phase locked loop. The method of claim 9, The input link is one of a link directly connected to the control station or a link connected to the control station through another network. The method of claim 9, And the system clock generated from the input link data is synchronized to a local oscillator clock in the control station when the input link is a link directly connected to the control station. The method of claim 9, And the system clock generated from the input link data is synchronized to a clock of the other network when the input link is a link connected to a control station through another network. A control station apparatus for clock synchronization between a base station and a control station in a mobile communication system, A transceiver for transmitting and receiving data through a connection link with a base station, A control unit which checks whether a GPS (Global Positioning System) clock reception is possible and whether data is received through the connection link; And a data generator for generating a system clock by restoring a clock from the received data under control of the controller when data is received through the link. The method of claim 15, Further comprising a GPS module for receiving the GPS clock, And the clock generator generates a system clock based on the received GPS clock under the control of the controller when the GPS clock is received. The method of claim 15, The control unit, And checking a connection link with the base station, selecting a link in which data is normally received, and providing data received in the selected link to the clock generator. The method of claim 15, The clock generator may include a local oscillator to generate a system clock by using a clock generated by the local oscillator under control of the controller when the GPS clock reception is impossible and data is not received through the link. Characterized by the device. A base station apparatus for clock synchronization between a base station and a control station in a mobile communication system, A transceiver for transmitting and receiving data through a connection link with a control station, A control unit which checks whether a GPS (Global Positioning System) clock reception is possible and whether data is received through the connection link; And a clock generator for generating a system clock by restoring a clock from the received data under control of the controller when data is received through the link. The method of claim 19, Further comprising a GPS module for receiving the GPS clock, And the clock generator generates a system clock based on the received GPS clock under the control of the controller when the GPS clock is received. The method of claim 19, The control unit, And checking a connection link with the base station, selecting a link in which data is normally received, and providing data received in the selected link to the clock generator.

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