KR20050113365A - Apparatus and metoth for sharing synchronous signal in bts - Google Patents

Abstract

The apparatus and method for synchronizing signal sharing in a mobile communication base station system according to the present invention are such that N x M BTSs can synchronize with each other with a reference time suitable for a CDMA system using one GPS antenna and a GPS signal distributor. It is possible to reduce the cost of installing the GPS antenna in each BTS, and also it is reliable at many BTSs at low cost through supplying GPS sync signal of BTS using digital cable and improving holdover time using low cost OCXO. To provide a GPS sync signal.

Description

Apparatus and method for synchronizing signal sharing in mobile communication base station system {APPARATUS AND METOTH FOR SHARING SYNCHRONOUS SIGNAL IN BTS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for sharing a synchronization signal in a mobile communication base station system. In particular, in a synchronous CDMA mobile communication system, a reference time for which a plurality of base stations (BTS) is suitable for a CDMA system using one GPS antenna and a GPS engine. The present invention relates to a synchronization signal sharing apparatus and a method for sharing a GPS synchronization signal so as to be synchronized with each other.

With the development of mobile communication systems, code division multiple access (CDMA) mobile communication systems have evolved into IMT-2000 (International Mobile Telecommunication-2000). IMT-2000 is a wired / wireless integrated next generation communication service system that provides multimedia roaming and multimedia services such as voice, high-speed data and video in terrestrial and satellite environments.

The IMT-2000 international standard can be largely divided into North American-led synchronous CDMA 2000 and European-led asynchronous broadband code division multiple access (W-CDMA).

The synchronous mobile communication system (CDMA 2000) and the asynchronous mobile communication system (W-CDMA) have different data transmission methods. That is, the synchronous mobile communication system transmits data by synchronizing the time of the transmitting side and the receiving side using a GPS satellite, and the asynchronous mobile communication system transmits and receives data only through the base station and the relay station without going through the satellite. .

On the other hand, asynchronous mobile communication system uses up to 57.6Kbps per subscriber in GSM / HSCSD standard in 2nd generation, up to 115Kbps / 384Kbps in GPRS / EDGE standard in 2.5th generation and DS (Direct Sequence) method in 3rd generation. It is evolving to the W-CDMA standard with a maximum transfer rate of 2Mbps.

However, the synchronous mobile communication system is based on IS-95 and various developments using 1x carriers are being made, which is called CDMA-200 1xEV. This is divided into Phase I and Phase II, where Phase I is High Data Rate (HDR) at up to 2.4Mbps, and Phase II is 1x TREME at 5.4Mbps.

In such a synchronous CDMA system, accurate time synchronization is required between base stations (hereinafter referred to as BTSs) by using a synchronization signal received from GPS for accurate transmission and reception of data.

To this end, 1PPS (One Pulse per Second) signal and TOD (Time of Day), which are synchronization signals transmitted from GPS satellites, are received for each BTS and used as a reference time, and also a reference for generating a BTS internal synchronization clock. It will be used as a reference source.

Therefore, all base station systems in the synchronous mobile communication system are equipped with a GPS synchronizer equipped with a GPS engine that directly receives a GPS signal.

The GPS synchronization device in the synchronous mobile communication base station system will be briefly described with reference to the accompanying drawings.

1 is a block diagram illustrating an apparatus for receiving a GPS synchronization signal in a synchronous mobile communication base station system according to the prior art.

As shown in FIG. 1, each of the synchronous mobile communication BTSs 10, 10n, 10n + 1 is a GPS clock using a GPS signal received through the GPS antennas 1, ..., n, n + 1. Each of the GPS clock generator 11 for generating a.

Each GPS clock generator 11 includes a GPS engine 11a and a synchronization signal generator 11b.

The GPS engine 11a receives the GPS synchronization signal through the GPS antenna 1 and provides it to the synchronization signal generator 11b.

The synchronizing signal generator 11b generates a CDMA synchronizing signal using the GPS synchronizing signal provided from the GPS engine 11a and outputs the generated CDMA synchronizing signal to each device in the BTS 10 (eg, channel card, Rx). / Tx card, etc.).

Since the GPS engine 11a needs to be directly connected to the GPS antenna 1, one GPS antenna 1 is connected and used. At this time, the GPS L1 signal is transmitted and received between the GPS engine 11a and the GPS antenna 1. The GPS engine 11a and the GPS antenna 1 must be connected by an RF coaxial cable.

In addition, the synchronization signal generator 11b performs a holdover function for maintaining a reliability of the CDMA synchronization signal for a predetermined time even when a GPS signal is not detected during operation to continuously supply the synchronization signal. In order to perform the over function, the synchronization signal generator 11b includes an Oven Contrilled Crystal Oscillator (OCXO) that generates its own clock. The holdover time is determined by the performance of this OCXO, and to implement a holdover for 24 hours, an expensive Double Oven Controlled Crystal Oscillator must be used. In other words, expensive OCXO must be used to increase the holdover time.

A method of generating a CDMA synchronization signal using a GPS synchronization signal receiver according to the related art having such a configuration will be described step by step with reference to FIG. 2.

2 is a flowchart illustrating an operation of a GPS synchronization signal processing method in a synchronous mobile communication base station system according to the prior art.

As shown in FIG. 2, first, during normal operation, the GPS engine 11a determines whether a GPS signal is received through the GPS antenna 1 (S101).

If the GPS signal is received, the received GPS signal is provided to the synchronization signal generator 11b, and the synchronization signal generator 11b extracts the TOD information and the 1PPS signal from the received GPS signal (S102).

By using the extracted 1PPS signal, the OCXO in the synchronization signal generator 11b is locked, and the extracted TOD information is transmitted to each device in the BTS 10, thereby ensuring a semi-permanent synchronization signal ( S103, S104).

However, when the GPS signal is not received in step S101, after driving the OCXO in the synchronization signal generating unit 11b and generating the TOD information using the OCXO's own counter, the generated TOD information is stored in each BTS 10. Transmission is made to the device (S105, S106). At this time, the synchronization signal generator 11b is to guarantee the synchronization signal for a holdover time set according to the mounted OCXO (S107).

Subsequently, when the holdover time is exceeded by determining whether the set holdover time is exceeded, generation of the synchronization signal is not performed, thereby making it difficult to guarantee the synchronization signal according to the failure of the system (S109).

However, if the holdover time is not exceeded in step S108, continuously check whether the GPS signal is received during the set holdover time, and when the reception of the GPS signal is detected, generate a synchronization signal using the received GPS signal, and check If the GPS signal is still not received, it generates its own synchronization signal during the set holdover time using its own OCXO.

As a result, the synchronization signal generating apparatus in the synchronous mobile communication system according to the prior art, as shown in Figure 1, should be provided with a GPS synchronization device including a GPS engine, all when installing a plurality of BTS, each of the GPS antenna and Should be connected. It has a problem that the cost is increased because it is distributed in close distance, and even if you want to use the GPS antenna to share the distance of several hundred meters by coaxial cable.

In addition, as shown in FIG. 2, since expensive OCXO is used to implement a large number of holdover times when a GPS signal is not received, this also has a problem of high cost.

Accordingly, the present invention is to solve the above problems according to the prior art, an object of the present invention is to provide a GPS synchronization signal to each of a plurality of BTS of a synchronous mobile communication system using one GPS antenna and a GPS engine, respectively. Accordingly, an object of the present invention is to provide an apparatus and method for sharing a synchronization signal in a mobile communication base station system capable of synchronizing reference times suitable for a synchronous CDMA system with each other.

In addition, another object of the present invention, when the GPS synchronization signal is not received, the synchronization signal sharing apparatus in the mobile communication base station system to ensure a stable GPS synchronization signal by increasing the holdover time without using an expensive OCXO And it provides a method.

According to an aspect of a GPS synchronization signal sharing apparatus in a mobile communication system according to the present invention for achieving the above object, GPS satellite signal distribution unit for distributing a GPS satellite signal received from a GPS antenna through at least one interface, respectively ; At least one BTS connected to the interface of the GPS satellite signal distribution unit, respectively, to generate visual information (TOD) and synchronization signal (clock signal) required by the 1PPS and TOD information of the GPS satellite signal distributed through the interface unit. It may include.

When the GPS satellite signal is not detected from the GPS satellite signal distribution unit, the at least one or more BTS extracts an arbitrary frequency signal from a link connected with the BSC and uses the extracted signal as an input source signal, and visual information required for the at least one BTS. Generate a sync signal.

The at least one BTS may include: a receiver configured to receive a GPS satellite signal distributed from a GPS satellite signal distributor; An input unit for inputting an input source signal extracted from an E1 / T1 link connected to a BSC for generating time information and a synchronization signal synchronized between the BTSs; A CDMA synchronization signal generator for generating time information and a synchronization signal using a GPS satellite signal received by the receiver or an input source signal input from the input unit according to an input source switching control signal; And generating an input source switching control signal for providing at least one of a GPS satellite signal received from the receiver or an input source signal input from the input unit as an input source signal for generating the time information and the synchronization signal. It includes an input source control unit provided by the negative.

When the GPS satellite signal is not received from the receiver, the CDMA synchronization signal generator is a signal extracted from an E1 / T1 link connected to the BSC input from the input unit according to an input source switching control signal provided from the input source controller. And an OCXO for generating the time information and the synchronization signal during the first holdover time set by increasing the counting to the previously generated time information and the synchronization signal using the input source signal. In this case, the OCXO generates time information and a synchronization signal during a second holdover time set using its counter when both signals from the receiver and the input unit are not received.

According to an aspect of a method for sharing a GPS synchronization signal of a BTS in a mobile communication system according to the present invention, distributing a received GPS satellite signal to at least one BTS through at least one or more interfaces, respectively; Each BTS may include generating TOD information and a synchronization signal (clock signal) required for each of the BTSs using 1PPS and TOD information of a GPS satellite signal distributed through a corresponding interface.

The generating of the TOD information and the synchronization signal may include: determining whether the GPS satellite signal or the input source signal is detected; a) when the GPS satellite signal is not detected and the arbitrary input source signal is detected, a first holdover set by counting and incrementing the previously generated TOD information and the synchronization signal in synchronization with the detected arbitrary input source signal Generating a CDMA synchronization signal for a time T1, and b) if the GPS satellite signal and any input source signal are not detected, during the second holdover time T1 set using its own counter, the TOD information and synchronization signal Generating a step.

According to another aspect of a GPS synchronization signal sharing apparatus in a mobile communication system according to the present invention, a first TOD information (TOD) and a synchronization signal (clock signal) using 1PPS and time information (TOD) of a received GPS satellite signal At least one main BTS for generating a; At least one sub-BTS connected to the main BTS in a daisy chain and generating second TOD information and a synchronization signal to be synchronized with the first TOD information and the synchronization signal transmitted from the main BTS.

And a GPS satellite signal distributor for providing GPS satellite signals received from a GPS antenna to the at least one main BTS, respectively, via an interface.

The at least one sub-BTS generates its own time information and a synchronization signal synchronized with the first TOD information and the synchronization signal transmitted from the main BTS, and provides the generated time information to the main BTS, and calculates the same according to the provided self-time information and the synchronization signal. The second TOD information and the synchronization signal are generated using the first TOD information and the transmission delay time information of the synchronization signal, and the generated second TOD information and the synchronization signal are transmitted to the lower BTSs daisy-chained with themselves. .

The at least one main BTS calculates a delay time between the self time information and the synchronization signal provided from the sub BTS and its first time information and the synchronization signal, and calculates the delay time information as the second time information of the sub BTS. And provide a synchronization signal as information for generating.

The at least one main BTS, the receiver for receiving a GPS satellite signal; An input unit for inputting an arbitrary input source signal extracted from an E1 / T1 link connected to a BSC to generate the first TOD information and a synchronization signal; a) extracting 1PPS and TOD information of the GPS satellite signal received by the receiver; b) using the extracted 1PPS and TOD information or an input source signal input from the input unit according to the input source switching control signal provided. A synchronization signal generator for generating one TOD information and a synchronization signal and providing the generated first TOD information and the synchronization signal to the sub BTS; And an input source switching control signal for providing at least one of a GPS satellite signal received from the receiver or an input source signal input from the input unit as an input source signal for generating the first TOD information and the synchronization signal. It includes an input source control unit provided to the generation unit.

The at least one sub BTS may include: a receiver configured to receive first TOD information and a synchronization signal from the main BTS; An input unit for inputting an arbitrary input source signal extracted from an E1 / T1 link connected to a BSC to generate second TOD information and a synchronization signal; The second TOD information and the synchronization signal are generated using the received first TOD information and the synchronization signal or the input source signal input from the input unit according to the input source switching control signal provided, and the generated second TOD information and the synchronization signal. A synchronization signal generator for providing a signal to a second sub BTS daisy-chained with itself; And an input source switching control signal for providing at least one of the first TOD information and the synchronization signal received from the receiver or the input source signal input from the input unit as an input source signal for generating the second TOD information and the synchronization signal. And an input source controller for providing the synchronization signal generator.

The synchronization signal generation unit may include a) generating second TOD information and a synchronization signal according to the TOD information provided from the main BTS and delay time information of the synchronization signal, and b) its own TOD information provided from the second sub BTS; Delay time calculation between the synchronization signal and the second TOD information and the time information generated by the self signal and calculating the delay time for providing the calculated delay time information as information for generating the third TOD information and the synchronization signal of the second sub-BTS. Wealth includes.

According to another aspect of the GPS synchronization signal sharing method in a mobile communication system according to the present invention, a first step of broadcasting the received GPS satellite signal to the at least one main BTS via an interface; At least one main BTS generates first TOD information (TOD) and a synchronization signal (clock signal) required for operation by using 1PPS and time information (TOD) of the transmitted GPS satellite signal, and generates the generated first TOD. Transmitting information and synchronization signals to sub-BTSs daisy-chained with themselves; The sub BTS may include a third step of generating second TOD information and a synchronization signal to be synchronized with the first TOD information and the synchronization signal transmitted from the main BTS.

The second step may include determining whether an input source signal extracted from an E1 / T1 link connected to a BSC and the GPS satellite signal are generated to generate the first TOD information and a synchronization signal; a) when the GPS satellite signal is not detected and the arbitrary input source signal is detected, a first holdover set by counting and incrementing the previously generated TOD information and the synchronization signal in synchronization with the detected arbitrary input source signal Generate the first TOD information and the synchronization signal during the time T1, and b) if neither the GPS satellite signal nor any input source signal is detected, during the second holdover time T1 set using its own counter. Generating a first TOD information and a synchronization signal.

In the second step, the delay time between the first TOD information and the synchronization signal synchronized with the first TOD information and the synchronization signal provided from the sub BTS and the first TOD information and the time information generated by the sub BTS is calculated, and the calculated delay is calculated. And providing time information as information for generating the second TOD information and the synchronization signal of the sub BTS.

The third step may include determining whether first TOD information and a synchronization signal and an input source signal transmitted from the main BTS are detected; a) when the first TOD information and the synchronization signal are not detected and the arbitrary input source signal is detected, the count is increased by counting the previously generated TOD information and the synchronization signal in synchronization with the detected input source signal. The first TOD information and the synchronization signal are generated during the first holdover time T1, and b) when all of the first TOD information and the synchronization signal and any input source signal are not detected, the first TOD information and the synchronization signal are set by using a counter. Generating the first TOD information and the synchronization signal during the second holdover time T1.

According to an aspect of the GPS synchronization device of the mobile communication base station system according to the present invention, an input module for extracting an arbitrary frequency signal from the E1 / T1 link connected to the BSC and inputs the extracted signal as an input source signal; Extracting 1PPS and TOD information from the received GPS satellite signal, and using the extracted 1PPS and TOD information or the input source signal input from the input module according to the input source switching control signal, A synchronization signal generation module for generating a synchronization signal and providing the generated TOD information and the synchronization signal to a lower BTS connected in a daisy chain; And an input source switching control signal for providing at least one of the received GPS satellite signal or an input source signal input from the input module as an input source signal for generating the TOD information and the synchronization signal to the synchronization signal generation module. It may include a control module unit for providing.

In addition, according to another aspect of the GPS synchronizer of the mobile communication base station system, an input module for extracting an arbitrary frequency signal from the E1 / T1 link connected to the BSC and inputs the extracted signal to the input source signal; Extracting the TOD information and the 1PPS signal from the synchronization signal transmitted from the upper BTS connected in the daisy chain, and using the extracted 1PPS and TOD information or the input source signal input from the input module according to the input source switching control signal provided. A synchronization signal generation module for generating TOD information and synchronization signals required for BTS operation and providing the generated TOD information and synchronization signals to a lower BTS connected in a daisy chain; And generating an input source switching control signal for providing at least one of a synchronization signal received from the upper BTS or an input source signal input from the input module as an input source signal for generating the TOD information and the synchronization signal. It may include a control module unit provided as a module.

According to another aspect of the method for sharing a GPS synchronization signal in a mobile communication base station system according to the present invention, determining whether a GPS satellite signal or a synchronization signal transmitted from a higher BTS is detected during normal operation of a BTS; Extracting 1PPS and TOD information from the received signal when a synchronization signal is received from the GPS satellite signal or the BTS as a result of the determination; By using the extracted 1PPS and TOD information, the first TOD information and a synchronization signal (clock signal) required for operation are generated and output for BTS operation, and the generated first TOD and synchronization signals of the lower BTS connected by daisy chains are generated. The method may include transmitting to the lower BTS to generate second TOD information and a synchronization signal required for operation.

Hereinafter, an apparatus and method for sharing a synchronization signal in a mobile communication base station system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram illustrating a network connection configuration for explaining a GPS synchronization signal sharing apparatus in a synchronous mobile communication base station system according to the present invention.

As shown in FIG. 3, the GPS synchronization signal sharing apparatus of the synchronous mobile communication system supplies power to the GPS timing antenna 100 and the GPS timing antenna 100 including the functions of the GPS L1 antenna and the functions of the GPS engine. TOD for BTS operation by receiving the GPS satellite signals distributed from the GPS timing signal distributor 200 and the GPS timing signal distributor 200 for supplying and distributing GPS satellite signals (1PPS signal and TOD information) to a plurality of BTSs. GPS synchronization devices 300 and 400 for generating information and synchronization signals. Here, the GPS synchronization devices 300 and 400 are mounted in each BTS (BTS 00-BTS NM). Although FIG. 3 illustrates that only the BTS 00 and the BTS 01 have GPS synchronizers 300 and 400, it should be understood that all other BTSs (BTS 10-BTS NM) may include the same GPS synchronizer.

In the GPS timing signal distributor 200, each BTS is grouped according to BTS IDs, and thus, each BTS is connected to each other in a chain form by ID. For example, as shown in FIG. 3, upper BTSs (BTS 00, BTS 10, and BTS N0) for each group are respectively connected to the GPS timing signal distributor 200, and lower BTSs corresponding to the upper BTSs for each group are respectively connected. The BTSs are daisy chained together.

The GPS synchronizer 300 in an upper BTS (for example, BTS 00) receives a GPS satellite signal received from the GPS timing signal distributor 200 to generate a GPS synchronization signal, and converts the generated GPS synchronization signal into a lower BTS (BTS). 01) to the GPS synchronizer 400. In addition, the GPS synchronizer 300 generates a CDMA synchronization signal using the generated GPS synchronization signal and supplies the same to each internal device. At this time, each of the GPS synchronization devices 3000 and 400 compensates for the time delay due to the mutual distance difference so that the same CDMA synchronization signal is shared.

Referring to the above operation in more detail, first, as shown in FIG. 3, the 1PPS signal and the TOD information generated by the GPS timing ANT 100 are passed through the GPS timing signal distributor 200 to the BTS (BTS 00). Is transmitted to the GPS synchronization device 300.

The GPS synchronizer 300 generates the CDMA synchronization signal by processing the necessary synchronization and time information inside the BTS 00 based on the information received from the GPS timing signal distributor 200, and then generates the generated CDMA synchronization signal (TOD information and Clock synchronization signal) is transmitted to each device (channel card, Rx / Tx card, etc.) inside BTS 00.

The GPS synchronizer 300 of BTS 00 transmits the GPS synchronization signal to the lower BTS, that is, the GPS synchronizer 400 of the BTS 01 of the next stage. At this time, the transmission delay time inevitably shown by the transmission distance is automatically corrected so that all BTSs can receive the GPS synchronization signal conforming to the CDMA standard.

That is, in FIG. 3, the GPS synchronization signal generated by the GPS synchronizer 300 of BTS 00 is transmitted to the GPS synchronizer 400 of BTS 01 (1), and the GPS synchronizer 400 is the GPS synchronizer 300. It generates its own synchronization signal in synchronization with the synchronization signal received from the system.

When the GPS synchronizer 400 retransmits the generated synchronization signal to the GPS synchronizer 300 of BTS 00 (2), the GPS synchronizer 300 of BTS 00 transmits between the received synchronization signal and its own synchronization signal. Calculate the delay time.

The GPS synchronizer 300 of the BTS 00 transmits information on the transmission delay time with the GPS synchronizer 400 of the BTS 01 to the GPS synchronizer 400 of the BTS 01 (3) so that the BTS 01 transmits this transmission delay time. The TOD information and the synchronization signal synchronized to within a predetermined range of Coordinated Universal Time (UTC) are generated by subtracting from the reference time and subtracting the subtracted time as the reference time.

After that, BTS 01 compensates for the transmission delay synchronization signal in turn with BTS 02 ..... BTS 0M, so that all BTSs connected in the group within the group synchronize to UTC within a certain range.

On the other hand, the GPS satellite signal is not received at the first upper BTS (for example, BTS 00), so all subsequent lower BTSs cannot receive the GPS synchronization signal, or there is a link between BTSs connected through a daisy chain. If not, the BTS itself has a holdover function to deliver a fixed time synchronization signal. At this time, the GPS synchronization device in each BTS can receive 8Khz signal extracted from E1 / T1 Link with BSC and use it as a synchronization signal of OCXO of 30 minutes holdover, for example, can replace 24 hours holdover OCXO. .

Hereinafter, the operation of each component according to the detailed internal configuration of the GPS synchronization device in each BTS and the state of the input reference source will be described in detail with reference to FIG. 4.

4 is a block diagram illustrating a detailed block configuration of the GPS synchronization device in the base station system shown in FIG.

As shown in FIG. 4, the GPS synchronizers in each BTS (herein, only the GPS synchronizers in BTS 00 and BTS 01 are referred to as examples) 300 and 400 may include a GPS / sync signal detector 301 and a GPS /. sync signal transmitter and receiver 302, GPS synchronization signal generator 303, delay calculation controller 304, input source controller 305, 8KHz input detector 306, 8KHz input receiver 307 and CDMA synchronization signal The generator 308 may be included.

The GPS / sync signal detector 301 detects a GPS satellite signal from the GPS timing signal distributor 200 or detects a synchronization signal between BTSs from a GPS synchronizer of a higher BTS, that is, a GPS signal. The satellite signal or the BTS synchronization signal is provided to the GPS / sync signal transmitter and receiver 302. In addition, the GPS / sync signal detector 301 provides the input source controller 305 with a confirmation signal for the detection result when the GPS satellite signal or the BTS synchronization signal is not detected.

The GPS / sync signal transmitter / receiver 302 receives the GPS satellite signal or the BTS synchronization signal provided from the GPS / sync signal detector 301 and provides the received signal to the GPS synchronization signal generator 303.

The GPS synchronization signal generator 303 generates a GPS synchronization signal using the PPS signal and the TOD information of the GPS satellite signal or the BTS synchronization signal provided from the GPS signal / sync transmitter and receiver 302 to delay calculation controller 304. Transmits to the GPS synchronization device of the lower BTS or transmits the generated GPS synchronization signal to the CDMA synchronization signal generator 308 to generate CDMA synchronization signals (OD information and clock synchronization signals) for its own BTS operation. To do that.

When the GPS synchronization signal generator 303 receives the GPS synchronization signal, the delay calculation controller 304 transmits the received GPS synchronization signal to the GPS synchronization device of the lower BTS, and receives the synchronization signal from the GPS synchronization device of the lower BTS. When the transmission delay time between the received synchronization signal and its own synchronization signal is calculated, the calculated transmission delay time information is provided to the lower BTSDML Hen synchronizer.

Then, the CDMA sync signal generator 308 generates a final CDMA sync signal to be supplied to each device in the BTS using the sync signal provided from the GPS sync signal generator 303.

The 8KHz input detector 306 is connected to the base station controller (BSC) of the synchronous mobile communication system and detects the input of the 8KHz signal extracted from the E1 / T1 link of the BSC to provide the detected 8KHz input signal to the 8KHz input receiver 307. And, it provides a confirmation signal for detecting whether to the input source control unit 305.

The 8KHz input receiver 307 receives the 8KHz signal provided from the 8KHz input detector 306 and provides it to the CDMA sync signal generator 308 as a source signal for generating the CDMA sync signal.

The input source controller 305 switches to the CDMA synchronization signal generator 308 according to the detection confirmation signal provided from the GPS / sync signal detector 301 and the confirmation signal from the 8KHz input detector 306. Provide control signals. That is, the input source controller 305 is received from the 8KHz input receiver 307 to generate the CDMA synchronization signal when the reception of the synchronization signal from the GPS or higher BTS is not detected from the GPS / sync signal detection unit 301. The input source signal of the CDMA synchronization signal generator 308 is switched to generate the CDMA synchronization signal using the 8 KHz signal.

Accordingly, the CDMA synchronization signal generator 308 generates the CDMA synchronization signal using the input source signal selected according to the switching control signal provided from the input source controller 305.

If a GPS satellite signal or a synchronization signal from a higher BTS is not detected, TOD information and a clock synchronization signal are generated using the 8KHz signal extracted from the E1 / T1 link connected to the BSC to guarantee the synchronization signal during the holdover time. It includes one OCXO to help.

A detailed operation of the GPS synchronizer 300 or 400 of the BTS having such a configuration will be described. In operation description, the operation of the GPS synchronizer 300 of the upper BTS and the GPS synchronizer 400 of the lower BTS are described. Let's look at each operation separately.

First, referring to the operation of the GPS synchronization device 300 of the upper BTS 00, the GPS signal detector 301 detects whether the GPS satellite signal is received from the GPS timing signal distributor 200 shown in FIG. The GPS signal is provided to the GPS signal transmission / reception unit 302, and provides a detection signal confirmation signal to the input source control unit 305.

If the GPS signal is detected, the input source controller 305 provides a switching control signal to the CDMA synchronization signal generator 308. That is, since the GPS signal is detected, the switching control signal for selecting the input source signal for generating the CDMA synchronization signal as the GPS synchronization signal without using the 8KHz signal extracted from the BSC is provided to the CDMA synchronization signal generator 3080. Therefore, the 8KHz signal extracted from the BSC is continuously extracted, but the extracted signal is not used for generating the CDMA synchronization signal.

The GPS signal transmitter and receiver 302 receives the GPS signal provided from the GPS signal detector 301 and provides the received GPS signal to the GPS synchronization signal generator 303.

The GPS synchronization signal generator 303 extracts 1PPS signal and TOD information from the GPS signals transmitted from the GPS signal transmitter and receiver 302 to the CDMA synchronization signal generator 308 as an input source for generating a CDMA synchronization signal. to provide.

In addition, the GPS synchronization signal generator 303 transmits the received GPS synchronization signal to the GPS synchronizer 400 of the lower BTS (for example, BTS 01 shown in FIG. 3) through the delay calculation controller 304.

After transmitting the GPS synchronization signal as described above, the GPS synchronization device 400 of the lower BTS receiving the signal generates its own synchronization signal in synchronization with the received GPS synchronization signal, and then generates the generated synchronization signal to the upper BTS (BTS 00). The delay calculation control unit 304 of the GPS synchronizer 300 is provided.

The delay calculation control unit 304 calculates the transmission delay time according to the time difference between the synchronization signal provided from the GPS synchronization device of the lower BTS and its GPS synchronization signal, and the information on the calculated transmission delay time is again converted into the GPS synchronization of the lower BTS. To the device 400.

Accordingly, the GPS synchronizer of the lower BTS subtracts the transmission delay time transmitted from the GPS synchronizer of the upper BTS from its reference time, and then synchronizes the time delayed within a certain range of UTC with the subtracted time as its reference time. It will generate a CDMA synchronization signal.

Meanwhile, the CDMA synchronization signal generator 308 of the upper BTS uses the GPS synchronization signal (IPPS signal and TOD information) provided from the GPS synchronization signal generator 303 to provide the CDMA synchronization signal to each device in its BTS. Will be provided. In this case, since the CDMA synchronization signal generator 308 is in a state where the GPS satellite signal is detected, the CDMA synchronization signal generator 308 locks the 8KHz input source of the own OCXO according to the switching control signal of the input source controller 305, In other words, the TOD information is transmitted to each internal device.

However, if the GPS satellite signal is not detected by the GPS satellite signal detector 301, the input source controller 305 is an 8KHz input signal extracted from an E1 / T1 link connected to the BSC from the 8KHz input detector 306. Determine if is detected.

As a result of determination, when an 8KHz input signal is detected, the input source controller 305 generates a switching control signal to the CDMA synchronization signal generator 308, that is, a CDMA synchronization signal (TOD information) through the OCXO from the detected 8KHz input source. It provides a control signal to enable.

Accordingly, the CDMA synchronization signal generator 308 generates the TOD information using the 8KHz input source using the COXO self counter according to the control signal provided from the input source controller 305, and then generates the generated TOD information in the BTS. Transmission to each device ensures generation of a synchronization signal during the holdover time T2 of the OCXO.

If the GPS signal is detected within the holdover time while continuously checking the detection of the GPS signal while performing the above operation, the CDMA sync signal is generated using the detected GPS sync signal as an input source, and if the holdover time is exceeded. In one case, failing to guarantee the synchronization signal causes a failure in the system.

On the other hand, when neither the GPS signal detector 301 nor the 8KHz input detector 306 detects an input signal, the input source controller 305 provides a switching control signal to the CDMA synchronization signal generator 308. After unlocking all of the input reference source signals (GPS / 8KHz) by the CDMA synchronization signal generator 308, TOD information is generated during the holdover time (T1) using the COXO self-counter and transmitted to each device in the BTS. Will be. At this time, the holdover time T2 is a time larger than the holdover time T1, approximately T2 is about 8-24 hours, and T1 is about 30 minutes to 1 hour.

Hereinafter, the operation of the GPS synchronizer 400 of the lower BTS 01 generating the CDMA synchronization signal according to the synchronization signal provided from the GPS synchronizer 300 of the upper BTS 00 will be described.

First, as shown in FIG. 4, the sync signal detector 301 detects whether a sync signal is received from the GPS synchronizer 300 of BTS 00, and provides the sensed sync signal to the sync signal transceiver 302. Provides a detection signal confirmation signal to the input source control unit 305.

If the synchronization signal from the GPS synchronizer 300 of the upper BTS 00 is detected, the input source controller 305 provides a switching control signal to the CDMA synchronization signal generator 308. That is, since the synchronization signal is detected from the upper BTS, the switching control signal for selecting the input source signal for generating the CDMA synchronization signal as the synchronization signal received from the upper BTS without using the 8 KHz signal extracted from the BSC is the CDMA synchronization signal. It is provided to the generation unit 308. Therefore, the 8KHz signal extracted from the BSC is continuously extracted, but the extracted signal is not used for generating the CDMA synchronization signal.

The sync signal transmitter and receiver 302 receives a sync signal provided from the sync signal detector 301 and provides the received sync signal to the GPS sync signal generator 303.

The GPS synchronization signal generator 303 extracts the 1PPS signal and the TOD information from the synchronization signal transmitted from the sync signal transmitter and receiver 302 to the CDMA synchronization signal generator 308 as an input source for generating a CDMA synchronization signal. to provide.

In addition, the GPS synchronization signal generator 303 transmits the received GPS synchronization signal to the GPS synchronization device (not shown) of the lower BTS 02 as shown in FIG. 3 through the delay calculation controller 304.

After transmitting the GPS synchronization signal as described above, the GPS synchronization device of the lower BTS 02 receiving the signal generates its own synchronization signal in synchronization with the received GPS synchronization signal, and then uses the generated synchronization signal to the upper BTS 01 GPS synchronization device 400. ) Is provided to the delay calculation control unit 304.

The delay calculation control unit 304 calculates a transmission delay time according to the time difference between the synchronization signal provided from the GPS synchronization device of the lower BTS 02 and its GPS synchronization signal, and returns information on the calculated transmission delay time to the lower BTS 02. To the GPS synchronizer.

Therefore, the GPS synchronizer of the lower BTS 02 subtracts the transmission delay time transmitted from the GPS synchronizer 400 of the upper BTS 01 from its own reference time, and then sets the subtracted time as its reference time in a predetermined range of UTC. It will generate the synchronized time and CDMA synchronization signal within.

Then, the delay calculation control unit 304 generates its own synchronization signal in synchronization with the synchronization signal received from the GPS synchronization device 300 of the upper BTS 00, and then generates the generated synchronization signal of the GPS synchronization device 300 of the upper BTS 00. Resend to.

Meanwhile, the CDMA synchronization signal generator 308 of the upper BTS 01 uses the GPS synchronization signal (IPPS signal and TOD information) provided from the GPS synchronization signal generator 303 to provide CDMA synchronization to each device in its BTS. Will provide a signal. At this time, since the CDMA synchronization signal generator 308 is in a state in which a synchronization signal provided from the upper BTS 00 is detected, the CDMA synchronization signal generator 308 locks an 8 KHz input source input to its OCXO according to the switching control signal of the input source controller 305. Then, the CDMA synchronization signal, that is, the TOD information is transmitted to each internal device.

However, if the sync signal is not detected from the upper BTS 00 by the sync signal detector 301, the input source controller 305 is 8KHz extracted from the E1 / T1 link connected to the BSC from the 8KHz input detector 306. Determine whether an input signal is detected.

As a result of determination, when an 8KHz input signal is detected, the input source controller 305 generates a switching control signal to the CDMA synchronization signal generator 308, that is, a CDMA synchronization signal (TOD information) through the OCXO from the detected 8KHz input source. It provides a control signal to enable.

Accordingly, the CDMA synchronization signal generator 308 generates the TOD information using the 8KHz input source using the COXO self counter according to the control signal provided from the input source controller 305, and then generates the generated TOD information in the BTS. Transmission to each device ensures generation of a synchronization signal during the holdover time T2 of the OCXO.

While performing the above operation, it is continuously checked whether reception of a synchronization signal from the upper BTS 00 is detected, and if a synchronization signal from the upper BTS 00 is detected within the holdover time, the detected synchronization signal is used as an input source. If the holdover time is exceeded, the synchronization signal cannot be guaranteed and a failure occurs in the system.

On the other hand, when neither the sync signal detector 301 nor the 8KHz input detector 306 detects an input signal, the input source controller 305 provides a switching control signal to the CDMA synchronization signal generator 308. After unlocking all of the input reference source signals (GPS / 8KHz) by the CDMA synchronization signal generator 308, TOD information is generated during the holdover time (T1) using the COXO self-counter and transmitted to each device in the BTS. It will be.

Hereinafter, a detailed configuration and operation of the GPS timing signal distributor 200 for distributing the GPS satellite signals received from the GPS timing antenna 100 to each BTS will be described.

FIG. 5 is a diagram illustrating an internal block configuration of the GPS timing signal distributor shown in FIG. 1.

First, the GPS timing antenna 100 illustrated in FIG. 3 is an antenna including a GPS L1 antenna and a GPS engine.

Since the GPS timing antenna 100 is made in consideration of 1: 1 connection with the destination device, a distribution method using a simple power divider such as a GPS L1 divider is impossible. In addition, the GPS timing antenna 100 requires a bidirectional communication process for setup with a destination device.

Therefore, it is necessary to add a device for controlling the bidirectional communication path between the plurality of GPS synchronization devices in the BTS and the GPS timing antenna 100.

In order to make this device function as a simple splitter like the GPS L1 signal splitter, only one of the GPS synchronizers in multiple BTSs can be GPS-timed using the characteristic of broadcasting GPS information like a GPS L1 antenna after the initial setup process. A bidirectional path is formed with the antenna 100 to perform communication with the timing antenna, and the remaining GPS synchronization devices receive synchronization signals broadcast by the GPS timing antenna 100 to synchronize with each other.

As such, in order to broadcast the GPS satellite signals received from the GPS timing antenna 100 to the GPS synchronization devices of higher BTSs in the plurality of BTS groups, the GPS timing signal distributor 200 as shown in FIG. 5 is required.

As shown in FIG. 5, the GPS timing signal splitter 200 may be configured to receive a GPS satellite signal from the GPS timing antenna 100 and to supply power to the self-power supply and the GPS timing antenna 100. And an interfacing unit 230 for interfacing the GPS satellite signals received through the power supply unit 220 and the reception unit 210 to the highest BTS of the group among the BTS groups grouped by a plurality of BTS IDs. .

As another embodiment, the GPS received from the GPS timing antenna 100 by configuring the interfacing unit 230 to be connected to all the BTSs, instead of transmitting the GPS satellite signals only to the highest BTS of each group by a broadcast transmission method. By transmitting the satellite signals to the GPS synchronizers in all the BTSs, the GPS synchronizers of each BTS may be used to generate and use the CDMA synchronization signals using the GPS satellite signals.

The synchronization signal sharing method of the BTS according to the present invention using the synchronization signal sharing apparatus in the mobile communication base station system according to the present invention will be described step by step with reference to FIG.

6 is a flowchart illustrating an operation method for sharing a GPS synchronization signal in a synchronous mobile communication base station system according to the present invention.

As shown in FIG. 6, it is first detected whether a GPS satellite signal is received during normal BTS operation (S201). Here, GPS satellite signal detection is performed only at the highest BTS (BTS 00, BTS 10, ,,,, BTS N0) of each group as shown in FIG.

On the other hand, the lower BTS detects whether a synchronization signal (sync) is received from the upper BTS (S205).

When the GPS satellite signal is detected in step S101, the upper BTS extracts 1PPS signal and TOD information from the received GPS satellite signal (S202).

Subsequently, the input source of the 8 KHz signal extracted through the E1 / T1 link connected to the BSC is locked using the extracted 1PPS signal, and the time information synchronized to a predetermined range of UTC using the extracted TOD information and The CDMA synchronization signal is generated and provided to each BTS device to guarantee the semi-permanent synchronization signal (S203 and S204).

When the GPS satellite signal is received at the highest BTS as described above, the CDMA synchronization signal is generated using the received signal, and the received GPS synchronization signal is also transmitted to the lower BTS.

Referring to the operation of the lower BTS receiving the synchronization signal from the upper BTS and generating the CDMA synchronization signal, it is first detected whether a GPS synchronization signal (sync) is received from the upper BTS (S205).

As a result of the detection, when the sync signal is received from the higher BTS, the 1PPS signal and the TOD information are extracted from the received sync signal (S206).

The extracted 1PPS signal is used to lock the input source of the 8 KHz signal extracted through the E1 / T1 link connected to the BSC, and the time information and CDMA synchronization synchronized even within a predetermined range of UTC using the extracted TOD information. By generating a signal and providing the signal to each BTS device, a semi-permanent synchronization signal is guaranteed (S203 and S204).

However, in order to generate the CDMA synchronization signal, the lower BTS uses the transmission delay time information according to the time difference between the GPS synchronization signal of the upper BTS and its GPS synchronization signal. That is, the lower BTS generates its own synchronization signal in synchronization with the synchronization signal received from the upper BTS, and then transmits the generated synchronization signal to the upper BTS.

The upper BTS calculates the transmission delay time according to the time difference between the lower BTS self synchronization signal received from the lower BTS and the synchronization signal generated by the lower BTS, and transmits the calculated transmission delay time information back to the lower BTS.

Accordingly, the lower BTS generates time information and a synchronization signal synchronized within a predetermined range of UTC by subtracting the transmission delay time transmitted from the upper BTS from its reference time as its reference time information.

After that, all the BTSs connected in the chain compensate for the transmission delay synchronization signal to the lower BTSs in the group to which all BTSs are chained so that all the BTSs are synchronized to UTC within a predetermined range. That is, as shown in FIG. 3, the BTS 00 is the BTS 011, the BTS 01 is the BTS 02, and so on. The CDMA synchronization signal is semi-permanently guaranteed by compensating the transmission delay synchronization signal.

Meanwhile, in FIG. 6, when neither the upper BTS nor the lower BTS receive the GPS satellite signal or the sync signal, respectively, each BTS is a signal of a constant frequency signal (for example, an 8 KHz signal) extracted from an E1 / T1 link connected to the BSC. It detects whether there is an input (S207).

If an 8KHz input signal is detected, TOD information is generated using the 8KHz input source using the COXO own counter, and then the generated TOD information is transmitted to each device in the BTS during the holdover time (T2) of the OCXO. The generation of the synchronization signal is guaranteed (S208, S209).

Subsequently, when the GPS signal or the sync signal from the upper BTS is detected within the holdover time T2, the CDMA sync signal is generated using the detected sync signal as an input source. If exceeded, the synchronization signal is not guaranteed and a fail occurs in the system (S211).

On the other hand, if the 8KHz input from the BSC is not detected in step S207, the self-OCXO freerun (S212), and after unlocking all of the input reference source signal (GPS / sync / 8KHz), COXO itself Using the counter, TOD information is generated during the hold over time T1 and transmitted to each device in the BTS (S213 and S214).

Subsequently, when a GPS signal or a sync signal from a higher BTS is detected within the holdover time T1, a CDMA sync signal is generated using the sensed sync signal as an input source, and the BSC within the holdover time T1. When the 8KHz signal is detected, the TOD information is generated during the hold-over time T2 by performing the above steps S207 to S209.

On the other hand, if the holdover time (T2) is exceeded, it is not possible to guarantee the synchronization signal (Fail) is generated (S211).

In the above-described preferred embodiment of the present invention, as shown in FIG. 3, the GPS timing signal distributor 200 is configured such that BTSs for each ID are grouped so that BTSs in each group are connected in a chain form.

Accordingly, the GPS timing signal distributor 200 transmits the GPS signal received from the GPS timing antenna 100 to the highest BTS of each group in a broadcast manner, and the highest BTS of each group transmits the received GPS signal to the lower BTS. to provide. The lower BTS then transmits the GPS synchronization signal to the lower BTS so that each BTS shares the synchronization signal. That is, the lower BTS calculates a transmission delay time of the GPS signal with its upper BTS and compensates the time, so that each BTS shares the same synchronization signal.

And, the highest BTS of each group detects whether a GPS signal from the GPS timing signal distributor 200 is received, and whether the lower BTSs receive a sync signal from their upper BTS, and is connected to the BSC when the corresponding signal is not received. By using the 8KHz input signal extracted from the E1 / T1 link, the OCXO generates its own CDMA synchronization signal (TOD).

Although the object of the present invention may be achieved through the configuration as described above, in another embodiment, the GPS timing signal distributor 200 shown in FIG. 3 is connected to all the BTSs so that all of the BTSs are separated from the GPS timing signal distributor 200. It is also possible to generate CDMA synchronization signals using the provided GPS satellite signals. That is, instead of receiving a GPS or sync signal from a higher BTS to generate a CDMA synchronization signal, all BTSs are interfaced with the GPS timing signal distributor 200 to receive GPS satellite signals from the GPS timing signal distributor 200 to receive the received GPS satellites. Satellite signals can be used to generate CDMA synchronization signals that can be synchronized to all of their BTSs.

In the case where the GPS signal is not detected, as in the above-described embodiment, the 8-kHz input signal extracted from the E1 / T1 link connected to the BSC may generate its own CDMA synchronization signal (TOD) in the OCXO. Anyone with ordinary knowledge of can understand.

The apparatus and method for synchronizing signal sharing in a mobile communication base station system according to the present invention as described above, using one GPS antenna and a GPS signal distributor, N x M BTSs synchronize with each other with a reference time suitable for a CDMA system. It is to be able to match. Therefore, there is an effect that can reduce the cost for installing the GPS antenna in each BTS.

In addition, by supplying the GPS synchronization signal of the BTS using a digital cable and improving the holdover time using a low-cost OCXO, it is possible to supply a reliable GPS synchronization signal to many BTS at a low cost.

1 is a block diagram illustrating an apparatus for receiving a GPS synchronization signal in a synchronous mobile communication base station system according to the prior art.

2 is a flowchart illustrating an operation of a GPS synchronization signal processing method in a synchronous mobile communication base station system according to the prior art.

3 is a diagram illustrating a network connection for explaining a GPS synchronization signal sharing apparatus in a synchronous mobile communication base station system according to the present invention;

4 is a detailed block diagram of a GPS synchronization device in a base station system shown in FIG.

5 is a block diagram illustrating an internal block configuration of the GPS timing signal distributor shown in FIG. 3;

6 is a flowchart illustrating an operation of a method for sharing a GPS synchronization signal in a synchronous mobile communication base station system according to the present invention.

* Description of the symbols for the main parts of the drawings *

100: GPS antenna 200: GPS timing signal splitter

210: receiver 220: power supply

230: interfacing unit 300, 400: GPS synchronization device

301: GPS / sync signal detector 302: GPS / sync signal transmitter and receiver

303: GPS synchronization signal generation unit 304: delay calculation control unit

305: input source control unit 306: 8KHz input detection unit

307: 8KHz input receiver 308: CDMA synchronization signal generator

Claims (32)

In the GPS synchronization signal sharing apparatus in a mobile communication system, A GPS satellite signal distributor configured to distribute GPS satellite signals received from the GPS antenna through at least one or more interfaces; At least one BTS connected to the interface of the GPS satellite signal distribution unit, respectively, to generate visual information (TOD) and synchronization signal (clock signal) required by the 1PPS and TOD information of the GPS satellite signal distributed through the interface unit. Mobile communication system comprising a. The method of claim 1, The at least one BTS is, When the GPS satellite signal is not detected from the GPS satellite signal distribution unit, a mobile communication for generating TOD information and a synchronization signal necessary for operation by extracting an arbitrary frequency signal from a link connected with a BSC as an input source signal system. The method of claim 1, The at least one BTS is, A receiver for receiving the GPS satellite signals distributed from the GPS satellite signal distributor; An input unit for inputting an input source signal for generating time information and a synchronization signal synchronized between the respective BTSs; A CDMA synchronization signal generator for generating TOD information and a synchronization signal using a GPS satellite signal received by the receiver or an input source signal input from the input unit according to an input source switching control signal; And An input source switching control signal for providing at least one of a GPS satellite signal received from the receiver or an input source signal input from the input unit as an input source signal for generating the time information and the synchronization signal to the CDMA synchronization signal generator; A mobile communication system comprising an input source control unit for providing. The method of claim 3, The arbitrary input source signal for generating the TOD information and the synchronization signal input from the input unit is a signal extracted from the E1 / T1 link connected to the BSC. The method of claim 3, The CDMA synchronization signal generator, When the GPS satellite signal is not received from the receiver, the signal extracted from the E1 / T1 link connected to the BSC input from the input unit is transferred as an input source signal according to an input source switching control signal provided from the input source controller. And an OCXO for generating time information and a synchronization signal during the first holdover time set by increasing counting of the generated TOD information and the synchronization signal. The method of claim 5, The OCXO, If both signals from the receiver and the input unit are not received, the mobile communication system generates TOD information and a synchronization signal during the second holdover time set using its own counter. In the GPS synchronization signal sharing method of the BTS in a mobile communication system, Distributing the received GPS satellite signals to at least one or more BTSs through at least one or more interfaces; Each BTS uses the 1PPS and TOD information of the GPS satellite signal distributed through the corresponding interface to generate its own TOD information and a synchronization signal (clock signal) for operation, respectively. Synchronization signal sharing method. The method of claim 7, wherein Generating the TOD information and the synchronization signal, Determining whether the GPS satellite signal or any input source signal is detected; a) when the GPS satellite signal is not detected and the arbitrary input source signal is detected, a first holdover set by counting and incrementing the previously generated TOD information and the synchronization signal in synchronization with the detected arbitrary input source signal Generates a CDMA synchronization signal for a time T1, b) if the GPS satellite signal and any input source signal are not detected, generating a TOD information and a synchronization signal for a second holdover time T1 set using a self-counter; GPS synchronization signal sharing method. The method of claim 8, And any input source signal for generating the TOD information and the synchronization signal is a signal extracted from an E1 / T1 link connected to the BSC. In the GPS synchronization signal sharing apparatus in a mobile communication system, At least one main BTS for generating first TOD information TOD and a synchronization signal (clock signal) using 1PPS and time information TOD of the received GPS satellite signal; And at least one sub BTS connected to the main BTS in a daisy chain and generating second TOD information and a synchronization signal to be synchronized with the first TOD information and the synchronization signal transmitted from the main BTS. The method of claim 10, And a GPS satellite signal distribution unit for respectively providing GPS satellite signals received from a GPS antenna to the at least one main BTS through an interface. The method of claim 10, The at least one sub BTS is, Generates and provides self time information and a synchronization signal synchronized with the first TOD information and the synchronization signal transmitted from the main BTS to the main BTS, and calculates the first TOD information and the synchronization signal according to the provided self time information and the synchronization signal. And generating second TOD information and a synchronization signal by using the transmission delay time information for and transmitting the generated second TOD information and the synchronization signal to lower BTSs daisy chained with themselves. The method of claim 11, The at least one main BTS is, A delay time between the self time information and the synchronization signal provided from the sub BTS and its first time information and the synchronization signal is calculated, and the calculated delay time information is used to generate the second time information and the synchronization signal of the sub BTS itself. Mobile communication system for providing information. The method of claim 10, The at least one main BTS is, A receiver for receiving a GPS satellite signal; An input unit for inputting an arbitrary input source signal extracted from an E1 / T1 link connected to a BSC to generate the first TOD information and a synchronization signal; a) extracting 1PPS and TOD information of the GPS satellite signal received by the receiver; b) generating first TOD information and a synchronization signal using the extracted 1PPS and TOD information or an input source signal input from the input unit according to the input source switching control signal provided, and generating the generated first TOD information and synchronization signal; A synchronization signal generation unit providing a to the sub BTS; And The synchronization signal generation unit may generate an input source switching control signal for providing at least one of a GPS satellite signal received from the receiver or an input source signal input from the input unit as an input source signal for generating the first TOD information and the synchronization signal. A mobile communication system comprising an input source control unit for providing a negative. The method of claim 14, The sync signal generator, When the GPS satellite signal is not received from the receiver, the signal extracted from the E1 / T1 link connected to the BSC input from the input unit is transferred as an input source signal according to an input source switching control signal provided from the input source controller. And an OCXO for generating the first TOD information and the synchronization signal during the set first holdover time by increasing the counting of the generated TOD information and the synchronization signal. The method of claim 15, The OCXO, The mobile communication system generates a first TOD information and a synchronization signal during a second holdover time set using its own counter when both signals from the receiver and the input unit are not received. The method of claim 14, The sync signal generator, The delay time between the TOD information and the synchronization signal provided from the sub BTS and the first TOD information and the time information generated by the sub BTS is calculated, and the calculated delay time information is used to generate the second TOD information and the synchronization signal of the sub BTS. A mobile communication system comprising a delay time calculator for providing as information for. The method of claim 10, The at least one sub BTS is, A receiver which receives first TOD information and a synchronization signal from the main BTS; An input unit for inputting an arbitrary input source signal extracted from an E1 / T1 link connected to a BSC to generate second TOD information and a synchronization signal; The second TOD information and the synchronization signal are generated using the received first TOD information and the synchronization signal or the input source signal input from the input unit according to the input source switching control signal provided, and the generated second TOD information and the synchronization signal. A synchronization signal generator for providing a signal to a second sub BTS daisy-chained with itself; And An input source switching control signal for providing at least one of first TOD information and a synchronization signal received from the receiver or an input source signal input from the input unit as an input source signal for generating the second TOD information and the synchronization signal; A mobile communication system comprising an input source control unit provided to the synchronization signal generation unit. The method of claim 18, The sync signal generator, When the first TOD information and the synchronization signal are not received from the receiving unit, a signal extracted from an E1 / T1 link connected to the BSC input from the input unit according to an input source switching control signal provided from the input source control unit is input source. And an OCXO which generates a second TOD information and a synchronization signal for a first holdover time set by increasing counting on previously generated TOD information and the synchronization signal as a signal. The method of claim 19, The OCXO, If both signals from the receiver and the input unit are not received, the mobile communication system generates a second TOD information and a synchronization signal during the second holdover time set using its own counter. The method of claim 18, The sync signal generator, a) generating second TOD information and a synchronization signal according to the TOD information and the delay time information of the synchronization signal provided from the main BTS; b) calculating a delay time between the self TOD information and the synchronization signal provided from the second sub BTS and the second TOD information and the time information generated by the second sub BTS, and calculating the delay time information using the third TOD information of the second sub BTS; And a delay time calculator configured to provide information for generating a synchronization signal. In the GPS synchronization signal sharing method in a mobile communication system, A first step of broadcasting a received GPS satellite signal to the at least one main BTS via an interface; At least one main BTS generates first TOD information (TOD) and a synchronization signal (clock signal) required for operation by using 1PPS and time information (TOD) of the transmitted GPS satellite signal, and generates the generated first TOD. Transmitting information and synchronization signals to sub-BTSs daisy-chained with themselves; The sub BTS includes a third step of generating second TOD information and a synchronization signal to be synchronized with the first TOD information and the synchronization signal transmitted from the main BTS. The method of claim 22, The second step, Determining whether an input source signal extracted from an E1 / T1 link connected to a BSC and the GPS satellite signal are generated to generate the first TOD information and a synchronization signal; a) when the GPS satellite signal is not detected and the arbitrary input source signal is detected, a first holdover set by counting and incrementing the previously generated TOD information and the synchronization signal in synchronization with the detected arbitrary input source signal Generate a first TOD information and a synchronization signal for a time T1; b) if both the GPS satellite signal and any input source signal are not detected, generating first TOD information and a synchronization signal during a second holdover time T1 set using its own counter; How to share GPS sync signal of BTS in system. The method of claim 22, The second step, The delay time between the first TOD information and the synchronization signal synchronized with the first TOD information and the synchronization signal provided from the sub BTS and the first TOD information and the time information generated by the sub BTS is calculated, and the calculated delay time information is calculated from the sub BTS. A method of sharing a GPS synchronization signal of a BTS in a mobile communication system, the method comprising providing the second TOD information and information for generating a synchronization signal. The method of claim 22, The third step, Determining whether first TOD information and a synchronization signal and an input source signal transmitted from the main BTS are detected; a) when the first TOD information and the synchronization signal are not detected and the arbitrary input source signal is detected, the count is increased by counting the previously generated TOD information and the synchronization signal in synchronization with the detected input source signal. Generate the first TOD information and the synchronization signal during the first holdover time T1; b) when both the first TOD information and the synchronization signal and any input source signal are not detected, generating the first TOD information and the synchronization signal during the second holdover time T1 set using its counter. GPS synchronization signal sharing method of the BTS in a mobile communication system comprising. In the mobile communication base station system, An input module for extracting an arbitrary frequency signal from an E1 / T1 link connected to the BSC and inputting the extracted signal as an input source signal; Extracting 1PPS and TOD information from the received GPS satellite signal, and using the extracted 1PPS and TOD information or the input source signal input from the input module according to the input source switching control signal, A synchronization signal generation module for generating a synchronization signal and providing the generated TOD information and the synchronization signal to a lower BTS connected in a daisy chain; And Provide to the sync signal generation module an input source switching control signal for providing at least one of the received GPS satellite signal or an input source signal input from the input module as an input source signal for generating the TOD information and the sync signal. GPS synchronization device of a mobile communication base station system comprising a control module unit. The method of claim 26, The synchronization signal generation module, When the GPS satellite signal is not received, the signal generated from the E1 / T1 link connected to the BSC input from the input module according to the input source switching control signal provided from the control module is previously generated as an input source signal. And an OCXO for generating TOD information and a synchronization signal required for operation during a set first holdover time by increasing the counting of the received TOD information and the synchronization signal. The method of claim 27, The OCXO, When neither the GPS satellite signal nor the input source signal from the input module is received, the GPS synchronizer of the mobile communication base station system generates TOD information and a synchronization signal required for operation during the second holdover time set using its own counter. . In the GPS synchronizer of the mobile communication base station system, An input module for extracting an arbitrary frequency signal from an E1 / T1 link connected to the BSC and inputting the extracted signal to an input source signal; Extracting the TOD information and the 1PPS signal from the synchronization signal transmitted from the upper BTS connected in the daisy chain, and using the extracted 1PPS and TOD information or the input source signal input from the input module according to the input source switching control signal provided. A synchronization signal generation module for generating TOD information and synchronization signals required for BTS operation and providing the generated TOD information and synchronization signals to a lower BTS connected in a daisy chain; And The synchronization signal generation module, an input source switching control signal for providing at least one of a synchronization signal received from the upper BTS or an input source signal input from the input module as an input source signal for generating the TOD information and the synchronization signal; GPS synchronization device of a mobile communication base station system comprising a control module unit provided by. In the GPS synchronization signal sharing method in a mobile communication base station system, Determining whether a GPS satellite signal or a synchronization signal transmitted from a higher BTS is detected during normal operation of the BTS; Extracting 1PPS and TOD information from the received signal when a synchronization signal is received from the GPS satellite signal or the BTS as a result of the determination; By using the extracted 1PPS and TOD information, the first TOD information and a synchronization signal (clock signal) required for operation are generated and output for BTS operation, and the generated first TOD and synchronization signals of the lower BTS connected by daisy chains are generated. A method of sharing a GPS synchronization signal of a mobile communication base station system comprising transmitting to a lower BTS to generate second TOD information and a synchronization signal required for operation. The method of claim 30, In the step of transmitting to the lower BTS, The BTS calculates a delay time such that the generated first TOD and synchronization signal and the second TOD and synchronization signal generated by the lower BTS are synchronized with each other, and then provides the calculated delay time information to the lower BTS. How to share GPS sync signal of system. The method of claim 30, Determining whether an input of an arbitrary signal extracted from an E1 / T1 link connected to a BSC is detected when neither the GPS satellite signal nor the synchronization signal transmitted from an upper BTS is detected; a) when the input of any signal extracted from the E1 / T1 link connected with the BSC is detected, the first number set by counting the previously generated TOD information and the synchronization signal in synchronization with the detected signal; Generate the TOD information and the synchronization signal required for operation during the holdover time (T1), b) when the input of any signal extracted from the E1 / T1 link connected to the BSC is not detected, generating TOD information and a synchronization signal for operation during the second holdover time T1 set using its own counter; GPS synchronization signal sharing method in a mobile communication base station system further comprising the step.