KR100901752B1 - Synchronizing method in a radio access station and in a remote unit, radio access station, and remote unit for supporting the same - Google Patents

Abstract

A synchronizing method in a radio access station and in a remote unit, radio access station, and remote unit for supporting the same are provided to synchronize the main unit and remote unit. The base station comprises a main unit(102), a remote unit(112), a connection line(128), a GPS antenna(126) and a RF antenna(130). The main unit transmits the first sync request by the remote unit. The main unit and remote unit are connected through the Ethernet. The time difference is calculated on the times information of the main unit and remote unit. The synchronizing signal of the remote unit is corrected through the time difference. Response to request or request is transmitted through the Ethernet frame. The synchronizing signal of the remote is delayed or preceded as the time difference or.

Description

Synchronizing Method in a Radio Access Station and In a Remote Unit, Radio Access Station, and Remote Unit for Supporting the Same}

The present invention relates to a synchronization method in a base station, a synchronization method in a remote unit, a base station supporting the same, and a remote unit, and more particularly, a method of synchronizing a main unit and a remote unit of the base station, and a base station supporting the same, and a remote unit. It is about a unit.

In general, if a general base station is installed in an area of a relatively small number of subscribers compared to the number of subscribers covered by the base station, waste is generated. In such an area, a remote unit (RU) such as a repeater may be installed. The waste factor is eliminated beforehand.

The base station of the in-building system (In-building System) for accommodating the terminal in the shadows and deaf areas in the building is implemented including a main unit (MU) and a plurality of RUs to control the RU.

In order to realize the synchronization of the inbuilding system, a GPS antenna and a GPS receiver are mounted on the MU and a plurality of RUs to receive signals from a GPS satellite and based on 1PPS (1 Pulse Per Second) extracted from the received signals. A sync signal or a reference signal is generated.

However, the base station of the in-building system must have a GPS antenna and a GPS receiver in the MU and a plurality of RUs, respectively, for accurate synchronization, and the building environment for the thick GPS antenna cable installation as well as the cost of installing the GPS antenna and the GPS receiver. There was a problem that the economic burden is increased due to the constraints.

In addition, in the case of a general in-building system, the use of multiple RUs in one MU has the effect of increasing coverage. However, since a channel card that is responsible for digital processing exists only in the MU, the cell processing capacity There was a problem that could not be increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem, and in the base station of the in-building system where it is difficult to install a GPS antenna, the GPS antenna exists only in the main unit, but the synchronization method in the base station that can synchronize the main unit and the remote unit, remote It is a technical problem to provide a synchronization method in a unit, a base station, and a remote unit.

Another object of the present invention is to provide a synchronization method in a base station, a synchronization method in a remote unit, a base station, and a remote unit capable of increasing cell processing capacity in an environment of a base station of an inbuilding system.

In the synchronization method in the base station according to an aspect of the present invention for achieving the above object is a synchronization method in the base station in which the main unit and the remote unit each count the number of times information every specific time based on the synchronization signal, Transmitting, by the main unit, a first synchronization request for an offset occurring between the synchronization signals of the main unit and the remote unit to the remote unit; Calculating a time difference between the information on the number of times of the main unit when the first synchronization request is transmitted and the information on the number of times of the remote unit when the first synchronization request is received by the remote unit; And correcting the synchronization signal of the remote unit through the time difference.

Synchronization method in a remote unit according to an aspect of the present invention for achieving the above object is a base unit in which the main unit and the remote unit is connected to each other by Ethernet,

A synchronization method in a remote unit according to an aspect of the present invention for achieving the above object is a base station comprising a main unit and a remote unit connected to each other by Ethernet, the main unit generated by the GPS signal from the main unit Periodically receiving a synchronization message including time information on a specific point of the synchronization signal of the apparatus; And comparing the time information of the specific point with the time information of the specific point measured when the synchronization message is received, obtaining a time offset, and generating a synchronization signal of the remote unit that compensates for the time offset. Characterized in that.

A base station according to an aspect of the present invention for achieving the above object is a base station in which the main unit and the remote unit each count the number of times information every specific time based on their synchronization signal, the synchronization of the main unit and the remote unit The main unit for transmitting a first synchronization request for an offset occurring between signals to a remote unit; And calculating a time difference between the information on the number of times of the main unit at the time of transmitting the first synchronization request and the information on the number of times of the remote unit at the time of receiving the first synchronization request, and correcting the synchronization signal of the remote unit through the time difference. It characterized in that it comprises a remote unit.

A remote unit according to an aspect of the present invention for achieving the above object is a main unit and a remote unit each of which counts the number of times information every specific time on the basis of its own synchronization signal, the main unit and the remote from the main unit A time sensing unit for measuring information on the number of times of the remote unit when the first synchronization request is received when receiving a first synchronization request for an offset generated between synchronization signals of a unit; And a synchronization signal controller configured to calculate a time difference between the information on the number of times of the main unit and the measured information on the number of remote units when transmitting the first synchronization request, and correct the synchronization signal of the remote unit through the time difference. It is characterized by.

As described above, according to the present invention, the limitation of the base station installation environment is corrected by correcting the offset for the synchronization signal between the main unit and the remote unit using Ethernet under an in-building system environment in which a GPS antenna is difficult to install. To overcome this problem, the synchronization of the base station can be realized at low cost.

In addition, according to the present invention, by mounting a channel card in the remote unit and implementing synchronization between the main unit and the remote unit, there is another effect of increasing coverage and of increasing cell processing capacity.

1 is a block diagram illustrating a base station according to an embodiment of the present invention, wherein the base station is a main unit 102, a remote unit 112, and the main unit 102 (hereinafter, referred to as 'MU'). And a connection line 128 such as a twisted pair (TP) cable, a GPS antenna 126, and an RF antenna 130 for connecting the remote unit 112 (hereinafter, referred to as RU).

Here, the MU 102 and the RU 112 are connected by a 100 BASE-T Ethernet connection line 128 and together form an in-building system.

The MU 102 includes a base station control unit 104, an L3 switch unit 106, and a first synchronization control unit 110. The MU 102 is responsible for the control and operation of the entire base station including the RU 112. ) To correct the synchronization signal of the RU 112 with respect to the offset generated between the synchronization signal of the RU 112 and the transmission delay time occurring at the connection line 128 between the MU 102 and the RU 112. Perform the function.

The base station control unit 104 is a base station controller and is responsible for the control and state management of the entire base station including the RU 112. In one embodiment, the base station control unit 104 is an RMP processor that controls the overall operation of the base station, such as control of the internal components of the base station, resource allocation, call processing, base station management (RAS Management), or control station interfacing (RAS Management Processor).

The L3 switch unit 106 transmits and receives a signal generated in the MU 102 through a medium-independent interface (MII), and transmits the signal to the RU 112 through the connection line 128. In addition, IP communication is performed with a control station (not shown), and serves as a transmission / reception path for traffic data and control information related to the base station and the control station. Here, the MII may be used for Ethernet frame transmission in the path 108 inside the MU 102.

The first synchronization controller 110 generates a synchronization signal of the MU 102 based on the signal received from the GPS antenna 126 and supplies this signal to each component of the MU 102. Here, the synchronization signal may be a 1 PPS (Pulse Per Second) or a system reference clock of 10 MHz.

Also, in order to synchronize the MU 102 and the RU 112, the first synchronization controller 110 transmits a message for correcting the synchronization signal of the RU 112 with respect to an offset between the synchronization signals and a transmission delay time. Hereinafter, the operation of the first synchronization controller 110 will be described in detail with reference to FIG. 2.

2 is a block diagram of the first synchronization controller 110 according to an embodiment of the present invention.

The first synchronization controller 110 controls the GPS receiver 202, the first synchronization signal generator 204, the first oscillator 206, the first synchronization signal controller 208, and the first time detector 210. Include.

The GPS receiver 202 receives a signal from the GPS antenna 126.

The first synchronization signal generator 204 extracts and outputs synchronization signals such as a system basic clock of 1 PPS, 10 MHz, and a time of day (TOD) signal from the signal received by the GPS receiver 202. In addition, the message generated by the first synchronization signal controller 208 to correct the synchronization signal of the RU 112 is transmitted to the L3 switch unit 106 through the path using the MII.

The sync signal output from the first sync signal generator 204 may be generated by dividing a clock received from the first oscillator 206.

The first oscillator 206 provides a clock for generating a system basic clock of 1 PPS and 10 MHz to the first synchronization signal generator 204. In an exemplary embodiment, the first oscillator 206 may be an oven controlled crystal oscillator (OCXO) or a template controlled crystal oscillator (TCXO).

The first sync signal controller 208 controls the GPS receiver 202 and the first sync signal generator 204 and generates a message for calibrating the sync signal of the RU 112.

The first synchronization signal controller 208 generates and transmits a first synchronization request message requesting to correct an offset occurring between the synchronization signals of the MU 102 and the RU 112. In addition, when a second synchronization request message is received from the RU 112 to measure the transmission delay time occurring at the connection line 128 between the MU 102 and the RU 112, a response message is generated and transmitted to the RU 112. do.

The messages are transmitted to the L3 switch unit 106 via the first time detector 210 and the first synchronization signal generator 204, and then transmitted to the RU 112.

The first sync signal controller 208 generates a first sync request message and transmits the generated first sync request message to the RU 112, and then receives information on the number of times when the first sync request message is transmitted from the first time sensor 210. A notification message for notifying the RU 112 of the count information is generated.

The first synchronization request message, the notification message, and the response message are periodically generated for synchronization of the MU 102 and the RU 112, and the MU 102 and the RU 112 are connected by Ethernet and each inside thereof is Since the communication paths 108 and 124 use MII, each message is transmitted using an Ethernet frame format.

When the first synchronization signal controller 208 generates the first synchronization request message and transmits the generated first synchronization request message to the RU 112, the first time detection unit 210 measures the number of times of information transmission when the first synchronization request message is transmitted. 1 is reported to the synchronization signal control unit 208.

The first time detector 210 maintains information on the number of times counted every specific time based on the synchronization signal of the MU 102 using a clock from the first oscillator 206 or another clock source.

For example, when the synchronization signal is a 1PPS signal and counts using a first clock oscillating in a cycle of Tclk, information about the number of times of incrementing from 0 to 1 per Tclk time is maintained based on the 1PPS signal.

If the information on the number of times when the first sync request message is transmitted is 10, it can be seen that the first sync request message is transmitted when 10 Tclk has elapsed from the time of generating the 1PPS signal. Hereinafter, a time point at which the first time sensor 210 measures the number of times when the first sync request message is transmitted will be described with reference to FIG. 3.

3 is a diagram illustrating a format of an Ethernet frame for transmitting a first sync request message and a time point at which the first time sensor 210 measures the count information according to an embodiment of the present invention.

The Ethernet frame 302 is a frame synchronization bit string (SFD), which indicates that the Ethernet frame 302 is composed of a preamble attached to the head of each frame for the frame synchronization and the SFD bit string in byte units. Is included as a header. It also includes a Taylor such as MAC frames (SRC, DST, TYPE, DATA) and Cyclic Redundancy Checking (CRC).

The first time detector 210 counts information of the number of times increased for each Tclk based on 1PPS, and when the Ethernet frame for the first synchronization request message is transmitted, a time point 306 at which transmission of the SFD 304 ends, or At the time when the transmission of the MAC frame is started 306, the count information is counted.

In the above-described embodiment, the first time detector 210 has been described as being separated from other components. However, in the modified embodiment, the first time detector 210 may include the first sync signal generator 204 or The first synchronization signal controller 208 may be implemented in a combined form.

Referring back to FIG. 1, the RU 112 includes an RU controller 114, an L2 switch unit 116, a channel card unit 118, an RF unit 120, and a second synchronization controller 122. It performs the function of transmitting / receiving data with the terminal, RF processing function, and MAC / PHY modem function. In addition, the synchronization signal of the RU 112 is corrected for the offset generated between the synchronization signal of the MU 102 and the RU 112 and the transmission delay time occurring at the connection line 128 between the MU 102 and the RU 112. Perform the function to

The RU control unit 114 is a controller that is in charge of control and state management for the RU 112 and collects and reports the state.

The L2 switch unit 116 distributes the packet received from the MU 102 via Ethernet to each component of the RU 112.

The channel card unit 118 performs digital processing of data transmitted and received with the terminal and a modem function in the MAC / PHY layer, and transmits and receives an IF (Intermediate Frequency) signal with the RF unit 120.

The channel card unit 118 according to an embodiment of the present invention is located in the RU 112 instead of the MU 102, so that the RU 112 and other RUs may be daisy chained to the MU 102. When connected in the form of a star, not only the coverage of the base station but also increases the cell processing capacity.

In addition, although the channel card unit 118 is located in the RU 112, since the synchronization signal corrected for the offset and the transmission delay time is supplied from the second synchronization controller 122, the channel card unit 118 is located between the MU 102 and the RU 112. It does not malfunction due to asynchronous problem.

The RF unit 120 converts an IF signal into an RF signal to high output amplification, or converts an RF signal into low noise amplification and converts it into an IF signal, thereby transmitting and receiving data with the terminal through the RF antenna 130.

The second synchronization controller 122 generates a synchronization signal of the RU 112 and supplies this signal to each component of the RU 112. The synchronization signal may be a 1 PPS, a system reference clock of 10 MHz, or a time division duflex (TDD) switching signal.

In addition, the second synchronization controller 122 processes a message for correcting the synchronization signal of the RU 112 with respect to an offset and a transmission delay time generated between the synchronization signal of the MU 102 and the RU 112. Hereinafter, the operation of the second synchronization controller 122 will be described in detail with reference to FIG. 4.

4 is a block diagram of the second synchronization controller 122 according to an embodiment of the present invention.

The second synchronization controller 122 includes a second synchronization signal generator 402, a second oscillator 404, a second synchronization signal controller 406, and a second time detector 408.

The second synchronization signal generator 402 generates and supplies synchronization signals such as a 1 PPS, a system basic clock of 10 MHz, a TDD switching signal, and a time of day (TOD) signal to each component of the RU 112. Do it.

In addition, the second synchronization signal generation unit 402 offsets the synchronization signal of the RU 112 and the synchronization signal of the MU 112 with respect to the synchronization signal of the RU 112 according to the command of the second synchronization signal control unit 406. And correction for the transmission delay time.

The synchronization signal output from the second synchronization signal generator 402 is transmitted based on the number of times when the first synchronization request message is transmitted from the MU 102 to the RU 112 or the synchronization signal of the MU 102. When the notification message including the time information is transmitted, the synchronization signal of the RU 112 is generated through the transmission time information.

In a modified embodiment, the synchronization signal output from the second synchronization signal generator 402 may be generated by dividing a clock received from the second oscillator 404.

The second oscillator 404 provides the second synchronization signal generator 402 with a clock for generating a 1PPS, a 10 MHz system basic clock, and a TDD switching signal. In one embodiment, the second oscillator 404 may be an OCXO or TCXO.

The second synchronization signal controller 406 controls the second synchronization signal generator 402 and corrects the synchronization signal of the RU 112.

When the second synchronization signal controller 406 receives the notification message for the first synchronization request message and the number of information requesting to correct the offset occurring between the synchronization signals of the MU 102 and the RU 112, the MU 102. ) And a second sync request message to the MU 102 for the measurement of the transmission delay time occurring at the connection line 128 between the RU 112. In addition, a response message to the second synchronization request message is received from the MU 102.

The second synchronization signal controller 406 primarily receives the MU 102 and the RU based on the information on the number of times measured by the second time detector 408 (408) and the information on the number of notification messages when the first synchronization request message is received. The offset occurring between the synchronization signals at 112 is corrected.

The RU 112 receives information about the number of times of the RU 112 when the second synchronization request message is transmitted and information about the number of times of the RU 112 when the response message is received from the second time sensing unit 408. The second synchronization signal generator 402 is instructed to perform secondary correction on the synchronization signal and output the finally corrected synchronization signal.

The second sync request message is periodically generated for synchronization of the MU 102 and the RU 112, and the MU 102 and the RU 112 are connected by Ethernet, and each inside thereof has a communication path using MII ( 108,124, the message is transmitted using an Ethernet frame format.

The second synchronization signal controller 406 notifies the number of times when the first synchronization request message is transmitted from the MU 102 to the RU 112 periodically or transmission time information based on the synchronization signal of the MU 102. When the message is transmitted, the synchronization time of the RU 112 is generated using the transmission time information.

For example, if the number information of the RU 112 that received the notification message is 3 and the number information received through the notification message is 1, the synchronization signal of the RU 112 that is preceded by the time corresponding to the number information 2 is 1. Instructs the second synchronization signal generation unit 402 to generate a new signal.

When the first synchronization signal controller 208 generates the first synchronization request message and transmits the generated first synchronization request message to the RU 112, the second time detection unit 408 counts the number of times of the RU 112 when the first synchronization request message is received. The information is measured and reported to the second synchronization signal controller 406.

In addition, the information on the number of times of the RU 112 when the second synchronization request message is transmitted and the number of times of the RU 112 when the response message is received are measured and reported to the second synchronization signal controller 406.

The second time detector 408 maintains information about the number of times counted every specific time based on the synchronization signal of the RU 112 through a clock from the second oscillator 404 or another clock source.

For example, when the synchronization signal of the RU 112 is 1PPS and counts using a second clock oscillating in a cycle of Tclk, information about the number of times of incrementing from 0 to 1 per Tclk time is maintained based on 1PPS.

Here, the count information of the RU 112 maintained by the second time detector 408 and the count information of the MU 102 maintained by the first time detector 210 are increased in counts for each Tclk. same.

In addition, referring to FIG. 3, the second time detector 408 and the first time detector 210 measure the number of times at the time point 306 when the transmission of the SFD 304 is terminated for a transmission / reception message. Since the same, detailed description will be omitted below.

In the above-described embodiment, the second time sensor 408 has been described as being separated from other components. However, in the modified embodiment, the second time sensor 408 may include the second synchronization signal generator 402 or The second synchronization signal controller 406 may be implemented in a combined form.

5A and 5B illustrate a process of correcting synchronization signals of the RU 112 in the MU 102 and the RU 112 according to an embodiment of the present invention.

Hereinafter, it is assumed that the MU 102 and the RU 112 receive clocks having a period of Tclk from the first oscillator 206 and the second oscillator 404, respectively, and maintain the number of times counted for each Tclk. Explain.

Here, the number of times of the MU 102 becomes 0 at the rising edge of the 1PPS synchronization signal of the MU 102 and increases by 1 for each Tclk, and the number of times of the RU 112 is 1PPS of the RU 112. It is assumed to be 0 at the rising edge of the synchronization signal and increased by 1 for each Tclk.

In addition, it is assumed that the transmission delay time between the MU 102 and the RU 112 is 1Tclk, and the offset between the 1PPS synchronization signal signals is 10Tclk (= difference in number information is 10).

Referring to FIG. 5A, when the number information 504a of the MU 102 is “000”, the time 502a calculated based on 1PPS of the corresponding MU 102 is 0Tclk. At the same time, the number information 506a of the RU 112 is "010", and the time 508a calculated based on 1PPS of the corresponding RU 112 is 10Tclk.

First, the first synchronization request controller 208 of the MU 102 requests the first synchronization request message 512a to correct the offset generated between the synchronization signals of the MU 102 and the RU 112. In this case, the first time detector 210 transmits “000”, which is the number information 504a of the MU 102 measured when the first sync request message 512a is transmitted, to the first sync signal controller 208. Report to.

However, the first synchronization request message 512a is transmitted when the number information 506a of the RU 112 is "010". However, since it is assumed that the transmission delay time is 1Tclk, the RU 112 is "011". Will be received.

Subsequently, the first synchronization signal controller 208 generates a notification message 514a including the received number information 504a “000” and transmits the notification message 514a to the RU 112. Here, the second time detection unit 408 of the RU 112 measures "011", which is the number information 506a of the RU 112 when the first synchronization request message 512a is received, and then the second synchronization signal controller. Report to (406).

Here, the second synchronization signal controller 406 stores "011", which is the number information 506a received from the second synchronization signal controller 406, in R1, which is a register 510a, and receives the received notification message ( The number information "000" included in 514a is stored in M1, which is a register 510a.

In addition, the second synchronization signal controller 406 performs the primary correction by leading or delaying 1PPS of the RU 112 by Tdiff. Here, Tdiff is calculated by the following formula (1).

Tdiff = (R1-M1) x Tclk

Here, considering the values of R1 and M1, since Tdiff is 11Tclk, correction is performed by preceding the 1PPS signal by the corresponding time. However, the advance of 1 PPS by Tdiff does not completely eliminate the offset, and further consideration should be given to the transmission delay time between the MU 102 and the RU 112, that is, the time when the messages were delayed and arrived at the RU 112. .

Accordingly, the second synchronization signal controller 406 transmits the second synchronization request message 516a to the MU 102 to measure the transmission delay time. Then, the response message 518a for the second synchronization request message is received from the MU 102.

In addition, the second time detector 408 measures and reports the number of information 506a at the time of transmitting and receiving the messages 516a and 518a. Here, the number information 506a at the time of transmission is "013", and the number information 506a at the time of reception is "016".

Subsequently, the second synchronization signal controller 406 stores the count information 506a in the register 510a, and stores "013" in R2 and "016" in R3.

The second synchronization signal controller 406 performs secondary correction by delaying 1PPS of the RU 112 by Tdelay. Here, Tdelay is calculated by Equation 2 below.

Tdelay = {(R3―R2) x Tclk-Tprocess} / 2

Here, Tdelay can be calculated by dividing the difference between R3 and R2 values. However, since the processing time Tprocess that occurs in the process of receiving and responding to the second synchronization request message 516a is required, Equation 2 is obtained in consideration of this.

In addition, assuming that Tprocess is 1Tclk as a value that the second synchronization signal controller 406 already knows, Tdelay becomes 1Tclk.

As a result, one PPS of the RU 112 is preceded by Toffset through two corrections, and the offset is removed. In this case, Toffset may be calculated by Equation 3 below.

Toffset = Tdiff-Tdelay

After the final correction, the number information 520a calculated based on the 1PPS of the MU 102 and the RU 112 also coincide with each other.

5B is a timing diagram illustrating a process in which offsets occurring between 1 PPS of the MU 102 and the RU 112 are removed.

Prior to the offset correction, the offset generated between the 1PPSs 502b and 504b of the MU 102 and the RU 112 is Toffset. However, after the primary offset correction, 1PPS 506b of RU 112 is preceded by Tdiff.

Then, after the secondary correction considering the transmission delay time, the 1PPS 508b of the RU 112 is delayed by Tdelay again, so that the offset is completely removed.

6 is a flowchart illustrating a synchronization method in a base station according to an embodiment of the present invention.

First, the MU transmits a first synchronization request for an offset generated between synchronization signals to the RU (S602). Here, the MU and the RU each count the number of times information based on their synchronization signals.

In one embodiment, the specific time may be a period of a clock generated by the oscillator inside the MU and the RU.

In one embodiment, the MU and RU constitute an in-building system, and each of the MU and RU may transmit and receive signals through MII.

Next, the MU transmits information on the number of times of the MU at the time of the first synchronization request to the RU (S604).

Next, the RU performs the first correction on the synchronization signal of the RU through the information on the number of times of the RU and the number of information received from the MU when the first synchronization request is received (S606). Here, the first correction is to advance or delay the synchronization signal of the RU by a time corresponding to the difference of the number information.

Next, the RU transmits a second synchronization request for the transmission delay time to the MU (S608).

Next, the RU receives a response to the second synchronization request from the MU (S610).

Next, the RU performs secondary correction on the synchronization signal of the RU based on the information on the number of times of the RU at the time of the second synchronization request and the information on the number of times of the response reception (S612). In this case, the second correction delays the first corrected synchronization signal by a time corresponding to a value obtained by dividing the difference between the number of information at the time of the second synchronization request and the number of information at the time of receiving the response.

In one embodiment, the MU and RU may be connected via Ethernet, and all the messages for request, notification, and response may be transmitted using an Ethernet frame format.

In one embodiment, the information on the number of times of transmitting the first and second sync requests and the number of times of receiving the response may be measured when transmission or reception of the SFD bit string of the Ethernet frame ends.

In one embodiment, the synchronization signal of the MU or RU may be a 1PPS, a system reference clock, or a TDD switching signal.

In one embodiment, the synchronization signal of the RU may be supplied to at least one of a channel card, a transceiver, and a RFU (Radio Frequency Unit) of the RU.

In the above-described embodiment, the RU removes the offset for the synchronization signal between the RU and the MU based on the number of times the MU transmits. Periodically receiving a synchronization message including time information on a specific point of the synchronization signal, and obtaining a time offset by comparing the time information on the specific point with the time information measured on the reception of the synchronization message; The synchronization signal of the remote unit having compensated for the time offset may be generated. In addition, the RU transmits a request for a transmission delay time to the MU and receives a corresponding response to perform correction for the transmission delay of the synchronization signal of the RU based on time information measured when the request is transmitted and when the response is received. Can be.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features.

Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts are included in the scope of the present invention. Should be.

1 is a block diagram illustrating a base station according to an embodiment of the present invention.

2 is a block diagram of a first synchronization controller according to an embodiment of the present invention.

FIG. 3 is a view illustrating a time point when an Ethernet frame format and a first time detector measure frequency information according to an embodiment of the present invention; FIG.

4 is a block diagram of a second synchronization controller according to an embodiment of the present invention.

5A and 5B illustrate a process of correcting a synchronization signal of an RU in an MU and an RU according to an embodiment of the present invention.

6 is a flowchart illustrating a synchronization method in a base station according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

202: GPS receiver 204: First synchronization signal generator

206: first oscillator 208: first synchronization signal controller

210: first time detector 402: second sync signal generator

404: second oscillator 406: second synchronization signal controller

408: second time detector

Claims (37)

In the synchronization method in the base station in which the main unit and the remote unit each count the number of times information every specific time on the basis of its synchronization signal, Transmitting, by the main unit, a first synchronization request for an offset occurring between the synchronization signals of the main unit and the remote unit to the remote unit; Calculating a time difference between the information on the number of times of the main unit when the first synchronization request is transmitted and the information on the number of times of the remote unit when the first synchronization request is received by the remote unit; And Correcting the synchronization signal of the remote unit via the time difference; Synchronization method in the base station comprising a. The method of claim 1, Sending, by the remote unit, a second synchronization request for a transmission delay time between the main unit and the remote unit to the main unit; And Upon receiving the response to the second synchronization request, correcting the synchronization signal of the remote unit corrected for the offset through a difference between the number of information of the remote unit at the time of transmitting the second synchronization request and at the reception of the response; step; The synchronization method in the base station further comprises. The method of claim 2, In the step of correcting for the transmission delay time, correcting the synchronization signal of the remote unit corrected for the offset by delaying the difference of the count information by a time corresponding to a bipartite value. Way. The method of claim 2, And the response to the second synchronization request or the second synchronization request is transmitted through an Ethernet frame. The method of claim 4, wherein The information on the number of times of the remote unit when transmitting the second synchronization request and when receiving the response is measured when the transmission or reception of the remote unit with respect to the starting frame delimiter (SFD) bit string of the Ethernet frame is finished. Synchronization method at the base station. The method of claim 1, And in the step of correcting for the offset, the synchronization signal of the remote unit is corrected by being delayed or preceded by the time difference. The method of claim 1, And transmitting information on the number of times of the main unit at the time of transmitting the first synchronization request from the main unit to the remote unit. The method of claim 1 And the main unit and the remote unit are connected via Ethernet. The method of claim 1, And the first sync request is transmitted via an Ethernet frame. The method of claim 9, And information on the number of times of the main unit at the time of transmitting the first synchronization request is measured when transmission of the SFD bit string of the Ethernet frame ends. The method of claim 1, And a synchronization signal of the remote unit is supplied to at least one of a channel card, a transceiver, and a radio frequency unit (RFU) of the remote unit. The method of claim 1, And a synchronization signal of the main unit or the remote unit is a 1 pulse per second (PPS), a system reference clock, or a time division time division duplex (TDD) switching signal. The method of claim 1, The specific time is a synchronization method in the base station, characterized in that the period of the clock generated by each of the oscillator inside the main unit and the remote unit. The method of claim 1, And the main unit and the remote unit constitute an in-building system. The method of claim 1, The main unit or the remote unit is a synchronization method in the base station, characterized in that using the MII (Medium Independent Interface). A base station including a main unit and a remote unit connected to each other by Ethernet, Periodically receiving, from the main unit, a synchronization message including time information on a specific point of the synchronization signal of the main unit generated by the GPS signal; And Comparing the time information of the specific point with the time information of the specific point measured when the synchronization message is received to obtain a time offset, and generating a synchronization signal of the remote unit that compensates for the time offset; Synchronization method in the remote unit comprising a. The method of claim 16, Sending a delay request message to the main unit and receiving a response message to the delay request message; And Compensating for a synchronization signal of the remote unit with respect to transmission delay times of the main unit and the remote unit through a time difference between the transmission time of the delay request mesh and the reception time of the response message; The synchronization method of the remote unit further comprises. A base station in which the main unit and the remote unit each count the number of times information every specific time based on their synchronization signal, The main unit sending a first synchronization request for an offset occurring between the synchronization signal of the main unit and the remote unit to the remote unit; And Calculating a time difference between the number of times of the main unit at the time of transmitting the first synchronization request and the number of times of the remote unit at the time of receiving the first synchronization request, and correcting the synchronization signal of the remote unit through the time difference; Remote unit; Base station comprising a The method of claim 18, The remote unit transmits a second synchronization request for the transmission delay time between the main unit and the remote unit to the main unit, and when receiving a response to the second synchronization request, when transmitting the second synchronization request and the response And a base station correcting the synchronization signal of the remote unit corrected with respect to the offset through a difference in the number information of the remote unit at the time of reception. The method of claim 19, And the remote unit corrects the synchronization signal of the remote unit corrected with respect to the offset by delaying the difference of the count information by a time corresponding to a bipartite value. The method of claim 19, The base station, characterized in that the response to the second synchronization request or the second synchronization request is transmitted through an Ethernet frame. The method of claim 21, And the remote unit measures information on the number of times of the remote unit at the time of transmitting the second synchronization request and at the reception of the response when the transmission or reception of the SFD bit string of the Ethernet frame ends. The method of claim 18, And the remote unit corrects the synchronization signal of the remote unit by delaying or preceding the synchronization signal by the time difference. The method of claim 18, And the main unit transmits information on the number of times of the main unit at the time of transmitting the first synchronization request to the remote unit. The method of claim 18 And the main unit and the remote unit are connected via Ethernet. The method of claim 18, And the first synchronization request is transmitted through an Ethernet frame. The method of claim 26, The base station, characterized in that the information on the number of times the main unit at the time of transmitting the first synchronization request is measured at the end of the transmission of the SFD bit string of the Ethernet frame. The method of claim 18, The remote unit includes a channel card, wherein the synchronization signal of the remote unit is supplied to the channel card. The method of claim 18, The specific time is a base station, characterized in that the period of the clock generated by each of the oscillator inside the main unit and the remote unit. The method of claim 18, And the main unit and the remote unit constitute an inbuilding system. In the main unit and the remote unit, each counting the number of times information based on their own synchronization signal every specific time, A time sensing unit for measuring information on the number of times of the remote unit upon receiving the first synchronization request when receiving a first synchronization request for an offset generated between the synchronization signal of the main unit and the remote unit from the main unit; And A synchronization signal controller for calculating a time difference between the number of times of the main unit and the measured number of times of the remote unit when transmitting the first synchronization request, and correcting the synchronization signal of the remote unit through the time difference; Remote unit comprising a. The method of claim 31, wherein The time detector measures information on the number of times when the second sync request is transmitted and the response is received for the second sync request between the main unit and the remote unit. And the synchronizing signal control unit corrects the synchronizing signal of the remote unit corrected with respect to the offset through a difference between the count information measured when the second synchronizing request is transmitted and when the response is received. 33. The method of claim 32, And the synchronizing signal control unit corrects the synchronizing signal of the remote unit corrected with respect to the offset by delaying the difference of the count information by a time corresponding to the divided value. The method of claim 31, wherein And the synchronization signal control unit corrects the synchronization signal of the remote unit by delaying or preceding the synchronization signal by the time difference. The method of claim 31, wherein And the synchronization signal control unit receives information on the number of times of the main unit at the time of transmitting the first synchronization request from the main unit. The method of claim 31, wherein Remote unit, characterized in that connected to the main unit via Ethernet. The method of claim 31, wherein And a channel card that performs modem functions in the digital processing of data or the MAC / PHY layer, wherein a synchronization signal of the remote unit is supplied to the channel card.

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