KR20160080437A - Node unit in distributed antenna system - Google Patents

Abstract

Provided is a node unit which makes up a distributed antenna system, comprising: a control portion which outputs a branch output blocking control signal to block transmission of the signal to an adjacent node which is branch-connected to the node unit through a transport medium, in a case where a reset command for resetting an operation of the node unit, and a command of turning on/off the power driving of the node unit, are received.

Description

A node unit in a distributed antenna system (NODE UNIT IN DISTRIBUTED ANTENNA SYSTEM)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed antenna system, and more particularly, to a distributed antenna system in which a node unit such as a main unit, a hub unit, a remote unit, etc. in a distributed antenna system performs an operation reset or power on / To prevent the unnecessary waves from being transmitted.

A Distributed Antenna System (DAS) generally includes a main unit (MU), which is a headend device, a hub unit (HU), which is an expansion device, a remote unit And a Remote Unit (RU).

When a problem occurs in a specific node, it is necessary to reset the operation of the node or to turn on / off the power supply unit (PSU). However, in a process of resetting a corresponding node operation and / or performing an on / off operation of a power supply unit due to a problem in a specific node in the distributed antenna system, a forward branch (i.e., a downlink branch) In the uplink direction), a spurious wave is transmitted to the upper branch, which may adversely affect the entire system and other nodes located at the upper or lower end thereof. Therefore, there is a need for a technique that can prevent spurious emissions from being transmitted to nodes at the upper and / or lower ends when a reset or power on / off is performed at a particular node in the distributed antenna system.

The present invention can prevent spurious waves from being transmitted to upper or lower branches of a corresponding node unit when a node unit such as a main unit, a hub unit, a remote unit, etc. in the distributed antenna system performs an operation reset or a power on / Method.

According to an aspect of the present invention, there is provided a node unit constituting a distributed antenna system (Distributed Antenna System)

When a reset command for resetting the operation of the node unit or an on / off command for turning on / off the power supply of the node unit is received, the node unit is connected to the branch and a control unit for outputting a branch output blocking control signal for blocking signal transmission to a connected adjacent node.

In one embodiment, a digital part for digital processing of the relaying signal; And

And converting serial digital data transmitted from a neighboring node through the transmission medium to parallel digital data for processing in the digital unit, the method comprising: converting parallel digital data into serial digital data for digital transmission of a relay signal through the transmission medium; A serializer / deserializer (SERDES) for converting,

When the reset command or the on / off command is received, the controller may switch the operation or output of the SERDES to a disable state through the branch output disable control signal.

In one embodiment, when the reset command or the on / off command is received, the control unit may further output an output disable control signal for switching the digital output relating to the relay signal in the digital unit to the inactive state have.

In one embodiment, the digital unit includes a digital signal processing unit that performs digital signal processing on the relay signal, and a digital front end output unit that configures a start end of the digital unit based on the signal transmission path and converts the analog signal into a digital signal Including,

The control unit may control the output of at least one of the digital signal processing unit and the digital front end output unit to be in an inactive state through the output inactivation control signal.

In one embodiment, the transmission medium for branching the node unit and the neighboring node is an optical cable,

An E / O converter for converting a relay signal into an optical signal and outputting the optical signal to a branch connected node through the transmission medium; And a photoelectric converter (O / E converter) for converting an optical signal related to a relay signal transmitted from a neighboring node through the transmission medium to an electric signal,

The control unit switches the operation or output of at least the electro-optical converter among the electro-optical converter and the photoelectric converter to a disable state through the branch output cutoff control signal when the reset command or the on / off command is received .

In one embodiment, when the reset command is received,

Wherein the control unit controls the reset operation of the node unit to be performed after the signal transmission to the branch connected node is blocked through the branch output blocking control signal and if the reset operation is completed, It is possible to output a branch output normalization control signal so that signal transmission is normalized.

In one embodiment, if the on / off command is received,

The control unit controls the power ON / OFF operation of the node unit to be performed after the signal transmission to the branch connected node is blocked through the branch output blocking control signal. When the ON / OFF operation is completed, And output the branch output normalization control signal so that signal transmission to the connected adjacent node is normalized.

According to the embodiment of the present invention, when a node unit such as a main unit, a hub unit, a remote unit or the like in the distributed antenna system performs an operation reset or a power on / off, a spurious wave is transmitted to the upper or lower branch of the corresponding node unit It is possible to prevent damage to the system.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an example of a topology of a distributed antenna system to which the present invention can be applied; FIG.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a distributed antenna system and a distributed antenna system, and more particularly,
3 is an exemplary block diagram for explaining a node unit having a spark propagation prevention function according to an embodiment of the present invention, taking a remote unit as an example;
4 is a flowchart of a method for preventing unwanted wave transmission according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of known related arts will be omitted when it is determined that the gist of the present invention may be unnecessarily obscured. In addition, numerals (e.g., first, second, etc.) used in the description of the present invention are merely an identifier for distinguishing one component from another.

Also, in this specification, when an element is referred to as being "connected" or "connected" with another element, the element may be directly connected or directly connected to the other element, It should be understood that, unless an opposite description is present, it may be connected or connected via another element in the middle.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an example of a topology of a distributed antenna system to which the present invention can be applied.

1, a distributed antenna system (DAS) includes a base station interface unit (BIU) 10, a main unit (MU) 20, (Hub Unit) 30, which is an extension node, and a plurality of RUs (Remote Unit) 40, which are arranged at remote service locations. Such a distributed antenna system may be implemented as an analog DAS or a digital DAS, and in some cases may be implemented as a mixed type (i.e., some nodes perform analog processing and the remaining nodes perform digital processing).

1 shows an example of a topology of a distributed antenna system, and a distributed antenna system may be used in an installation area and an application field (for example, an in-building, a subway, a hospital, Stadiums, etc.), various topology modifications are possible. In this case, the number of BIU 10, MU 20, HUB 30, RU 40, and the connection relationship of the upper and lower ends of the BIU 10, the HUB 30, and the RU 40 may differ from those of FIG. Also, in the distributed antenna system, the HUB 20 is utilized when the number of branches to be branched from the MU 20 to the STAR structure is limited, compared to the number of RUs 40 required for installation. Therefore, the HUB 20 may be omitted when the number of the RUs 40 required to be installed can be sufficiently satisfied even with a single MU 20, or when a plurality of MUs 20 are installed.

Hereinafter, with reference to the topology of FIG. 1, each node in the distributed antenna system applicable to the present invention and its function will be described in turn.

A Base Station Interface Unit (BIU) 10 serves as an interface between a Base Station Transceiver System (BTS) such as a base station and an MU 20 in a distributed antenna system. In FIG. 1, a plurality of BTSs are connected to a single BIU 10, but the BIU 10 may be separately provided for each service provider, for each frequency band, and for each sector.

Generally, since the RF signal transmitted from the BTS is a high power signal, the BIU 10 generally transmits a RF signal of a high power level to the MU 20 And transfers it to the MU 20. 1, the BIU 10 receives a signal of a mobile communication service for each frequency band (or for each service provider, sector) as shown in FIG. 1, combines the signals, ), As shown in FIG.

If the BIU 10 lowers the high power signal of the BTS to a low power and then combines the mobile communication service signals and transmits them to the MU 20, the MU 20 combines the received mobile communication service signals Relay signal ") for each branch. In this case, when the distributed antenna system is implemented as a digital DAS, the BIU 10 includes a unit that performs a function of converting a high-power RF signal of the BTS into a low-power RF signal, and a unit that performs an IF (Intermediate Frequency) And converted into a unit for performing a digital signal process and combines them. Alternatively, if the BIU 10 only performs a function of lowering the high power signal of the BTS to low power, the MU 20 may combine the transmitted relay signals and distribute the relay signals for each branch.

As described above, the combine relay signal distributed from the MU 20 is directly transmitted to the RU 40 or the HUB 20 via the branch, and each RU 40 transmits the combined combine relay signal to the frequency band (Analog signal processing in case of analog DAS, digital signal processing in case of digital DAS). Accordingly, each RU 40 transmits a relay signal to a user terminal in its service coverage through a service antenna. The specific functional configuration of the RU 40 will be described later in detail with reference to FIG.

1, a case where an RF cable is connected between the BTS and the BIU 10 and a case where the BIU 10 and the MU 20 are connected by the RF cable, and all the connections from the MU 20 to the lower end are connected by the optical cable, The signal transport medium between each node can also be modified in various ways. For example, the BIU 10 and the MU 20 may be connected through an RF cable, but may be connected through an optical cable or a digital interface. As another example, an optical cable is connected between the MU 20 and the HUB 30 and an RU 40 directly connected to the MU 20, and an RF cable, a twisted cable, a UTP Cable, or the like. As another example, in another example, the RU 40 directly connected to the MU 20 may also be implemented in such a manner that they are connected via an RF cable, a twisted cable, a UTP cable, or the like.

However, the following description will be made with reference to Fig. Therefore, in this embodiment, the MU 20, the HUB 30, and the RU 40 may include optical transceiver modules for all-optical conversion / photoelectric conversion, and when interconnecting nodes with a single optical cable, Wavelength Division Multiplexing (WDM) devices. This can be clearly understood from the functional description of the RU 40 in FIG. 2, which will be described later.

The distributed antenna system can be connected to an external management apparatus (NMS (Network Management Server or System) in FIG. 1 via the network.) Accordingly, the manager can remotely monitor the status and problem of each node of the distributed antenna system through the NMS And can control the operation of each node remotely.

FIG. 2 is an exemplary diagram illustrating a case where a spurious wave is transmitted to an upper or a lower branch according to a reset at a specific node unit or a power source on / off in a distributed antenna system to cause system damage.

As shown in FIG. 2, when a problem occurs in the operation of the MU (main unit) as a node unit constituting the distributed antenna system (see CASE 1 in FIG. 2), the MU is reset or the power on / In doing so, the unnecessary wave is transmitted to the RU of the lower level connected to the branch, and system damage may occur to the lower level RU.

As another example, when a problem occurs in a specific RU as a node unit constituting a distributed antenna system (see CASE 2 in FIG. 2) and performs a reset or power on / off operation of the corresponding RU, Spurious waves are transmitted to adjacent RUs connected to the branch, which can cause system damage.

The reason why the spurious waves are generated when a problem occurs in a specific node constituting the distributed antenna system and the corresponding node is reset or turned on / off is as follows. Generally, when the power is turned on, spurious waves may be generated in a process of turning on the power or turning on the analog or digital elements in the node. Similarly, even when the power is off, an analog element or a digital element in a node that has performed a normal operation may be suddenly cut off and generate a spurious wave. Also, even in the reset operation, spurious waves may be generated when the operation of each element is activated before the initialization process of the elements in the node is completed after the reset operation.

The embodiment of the present invention proposes a method for preventing the unnecessary waves generated in the reset or power on / off process at the specific node from being transmitted to the adjacent node connected to the upper or lower branch. This can be clearly understood from the following description of FIG. 4, which will be described later.

Prior to describing FIG. 4, an internal configuration of an RU will be described first as an example of a node unit constituting a distributed antenna system, in order to facilitate understanding of a spurious wave transmission prevention method according to an embodiment of the present invention.

3 is an exemplary block diagram illustrating a node unit having a spark propagation prevention function according to an embodiment of the present invention, taking a remote unit as an example. Here, the block diagram of FIG. 3 illustrates one implementation of an RU 40 within a digital DAS in which the inter-node connection is via an optical cable.

Referring to FIG. 3, the RU 40 includes an optical to electrical converter 50, a serializer (SERDES) 50, and a multiplexer / demultiplexer 50 based on a downlink signal transmission path (i.e., a forward path) A deserializer 44, a deframer 52, a digital signal processor (DSP) 70, a digital / analog converter (DAC) 54, an up converter 56, (Amplification Unit) 58.

Thus, in the forward path, the optical relaying signal digitally transmitted through the optical cable is converted into an electric signal (serial digital signal) by the optical / electrical converter 50, and the serial digital signal is converted by the SERDES 44 into parallel digital And the parallel digital signal is reformatted by the de-framer 52 so that the digital signal processor 70 can process the frequency band. The digital signal processing unit 70 performs functions such as digital signal processing, digital filtering, gain control, and digital multiplexing for each frequency band with respect to the relay signal. The digital signal processor 70 may be implemented as an FPGA (Field Programmable Gate Array). The digital signal that has passed through the digital signal processing unit 70 is converted to an analog signal via the digital / analog converter 54 constituting the final stage of the digital part based on the signal transmission path. At this time, the analog signal is an IF signal, and is up-converted to an analog signal of the original RF band through the up-converter 56. In this way, the analog signal converted into the original RF band (i.e., the RF signal) is transmitted through the PAU 58 and transmitted through the service antenna (not shown).

The RU 40 includes a Low Noise Amplifier (LNA) 68, a down converter 66, an analog-to-digital converter (ADC) 68, A digital signal processor (DSP) 70, a framer 62, a SERDES 44, and an electrical to optical converter 60. The digital signal processor (DSP)

Thus, in the reverse path, the RF signal (i.e., the terminal signal) received via the service antenna (not shown) from the user terminal (not shown) in the service coverage is low noise amplified by the LNA 68, 66, and the converted IF signal is converted into a digital signal by an analog-to-digital converter 64 (which is the digital component constituting the beginning of the digital part on the basis of the uplink signal path) And transmitted to the digital signal processing unit 70. [ The digital signal passed through the digital signal processing unit 70 is formatted into a format suitable for digital transmission through the framer 62 and converted into a serial digital signal by the SERDES 44, And is transmitted to the upper end through the optical cable.

Although not explicitly shown in FIG. 3, when the RUs 40 are cascade-connected with each other as in the example of FIG. 1 and the relay signal transmitted from the upper end is transmitted to the adjacent RUs in the cascaded lower end The following method can be used. For example, when an optical relay signal digitally transmitted from an upper stage is transmitted to a neighboring RU of a lower stage cascaded, the optical relay signal digitally transmitted from the upper stage is transmitted to the optical / electrical converter 50 -> SERDES 44 - The descrambler 52, the framer 62, the SERDES 44, and the photodetector 60 in that order.

Although the SERDES 44 and the digital signal processor (DSP) 70 are shown as shared in the downlink and uplink signal propagation paths in FIG. 3, they may be separately provided for each path. In addition, although the optical / electrical converter 50 and the optical / electrical converter 60 are shown separately in Fig. 3, they may be implemented in a single optical transceiver module.

4 is a flowchart illustrating a method for preventing unwanted wave transmission according to an embodiment of the present invention. Hereinafter, a method for preventing unwanted wave transmission according to an embodiment of the present invention will be described in detail with reference to the flowchart of FIG. Here, the flowchart of Fig. 4 can be executed in the specific node units (i.e., MU 20, HUB 30, RU 40) constituting the distributed antenna system, as described above with reference to Fig.

In step S110 of Fig. 4, a reset command or a power on / off command of the node is received at the specific node unit. The reset command and the power on / off command may be hardware (H / W) reset or on / off commands for the node unit executed by the operator in the field, remote software (S / W) reset or an on / off command.

When the node reset command or the power on / off command is received as described above, the output of the upper end and / or the lower end branch of the corresponding node is blocked in step S120. This can be executed by the control unit 80 shown in Fig. 3, and more specifically, the following method can be used.

In one embodiment, as a method of interrupting the output of the upper or lower branch, a method of disabling the operation or output of the component responsible for the upper or lower branch output may be applied.

As an example, as a component relating to the output of the upper or lower branch, a method of switching the operation or output of the SERDES 44 shown in Fig. 3 to the inactive state may be used. That is, when a reset command or a power on / off command for the node is received, the controller 80 may output a branch output blocking control signal for switching the operation or output of the SERDES 44 to the inactive state.

As another example, a method of converting the operation or output of the electro-optic converter 60 shown in Fig. 3 into the inactive state may be used as the constituent related to the output of the upper or lower branch. That is, when a reset command or a power on / off command for the corresponding node is received, the control unit 80 outputs a branch output blocking control signal for switching the operation or output of the electric / optical converter 60 to the inactive state .

In a similar manner to the above, a method of converting the operation or output of the optical / electrical converter 50 shown in Fig. 3 into the inactive state may also be used. For example, in the downlink signal transmission path, when a downlink signal is transmitted to a neighboring RU in a lower stage cascaded with a specific RU as a problem node, the downlink signal is transmitted through the optical / The method of switching it to the deactivated state can prevent the unnecessary waves from being transmitted to the adjacent RU of the lower level.

It is also possible to deactivate the operation or the output of the framer 62 and / or the de-framer 52 of FIG.

In another embodiment, as a method of interrupting the output of the upper or lower branch, a method of switching the operation or output of the component itself capable of generating the spurious wave to the inactive state may be applied. Particularly, in the case of a node unit including a digital part, it may be an effective method to convert the operation or output of the digital constituent related to the digital output capable of outputting digital spurious relating to the relay signal in the digital part to the inactive state .

As an example, a method of switching the operation or output of the digital signal processing unit 70 shown in Fig. 3 to the inactive state can be used. In addition, when the digital signal processor 70 is implemented as an FPGA, a control is performed so that a value output from the FPGA is output as a value of '0' or a spurious wave is not radiated, instead of a method of switching the operation or output to the inactive state It is also possible to do this.

In another example, a digital component (e. G., Analog / digital < / RTI > in FIG. 3), which constitutes the beginning of a digital part on the basis of a signal propagation path, Converter 64) to an inactive state may also be used.

The reason why the digital output or the digital component in the digital part is switched to the inactive state as described above is that when performing the reset operation or the power on / off operation according to the reset command or the power on / off command, As shown in FIG. The switching to the inactive state of the various methods described above can be performed by the branch output cutoff control signal output from the control unit 80 in Fig.

After the output to the upper or lower branch is interrupted according to the above-described step S120, the control unit 80 performs a reset operation or a power on / off operation of the node unit in step S130.

When the reset operation or the power on / off operation according to step S130 is completed, the control unit 80 switches the output to the upper or lower branch which has been previously cut off to the normalized state according to step S140. This is performed by the branch output normalization control signal outputted from the control unit 80. The method of normalizing the branch output is to switch the operation or the output of the constituent units deactivated for interrupting the branch output described above to the enable state It can be done in a way.

According to the above-described method for preventing unnecessary wave transmission according to the embodiment of the present invention, when a node reset command or a power on / off command is received, before performing a reset operation or a power on / It is possible to prevent the unnecessary waves from being transmitted to the upper or lower branch to damage the entire system.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims And changes may be made without departing from the spirit and scope of the invention.

Claims (7)

As a node unit constituting a distributed antenna system (Distributed Antenna System)
When a reset command for resetting the operation of the node unit or an on / off command for turning on / off the power supply of the node unit is received, the node unit is connected to the branch and a branch output interruption control signal for interrupting signal transmission to a connected adjacent node
/ RTI >
The method according to claim 1,
A digital part for digital processing of the relaying signal; And
And converting serial digital data transmitted from a neighboring node through the transmission medium to parallel digital data for processing in the digital unit, the method comprising: converting parallel digital data into serial digital data for digital transmission of a relay signal through the transmission medium; A serializer / deserializer (SERDES) for converting,
Wherein the control unit switches the operation or output of the SERDES to a disable state via the branch output blocking control signal when the reset command or the on / off command is received.
3. The method of claim 2,
Wherein the control unit further outputs an output disable control signal for switching the digital output relating to the relay signal in the digital unit to the inactive state when the reset command or the on / off command is received.
The method of claim 3,
The digital unit includes a digital signal processing unit for performing digital signal processing on the relay signal and a digital front end output unit for converting the analog signal into a digital signal by constituting a start end of the digital unit based on the signal transmission path,
Wherein the control unit controls the output of at least one of the digital signal processing unit and the digital front end output unit to be switched to an inactive state through the output deactivation control signal.
The method according to claim 1,
Wherein the transmission medium for branching the node unit and the adjacent node is an optical cable,
An E / O converter for converting a relay signal into an optical signal and outputting the optical signal to a branch connected node through the transmission medium; And a photoelectric converter (O / E converter) for converting an optical signal related to a relay signal transmitted from a neighboring node through the transmission medium to an electric signal,
The control unit switches the operation or output of at least the electro-optical converter among the electro-optical converter and the photoelectric converter to a disable state through the branch output cutoff control signal when the reset command or the on / off command is received Node unit.
The method according to claim 1,
When the reset command is received,
Wherein the control unit controls the reset operation of the node unit to be performed after the signal transmission to the branch connected node is blocked through the branch output blocking control signal and if the reset operation is completed, And outputs a branch output normalization control signal so that signal transmission is normalized.
The method according to claim 1,
When the on / off command is received,
The control unit controls the power ON / OFF operation of the node unit to be performed after the signal transmission to the branch connected node is blocked through the branch output blocking control signal. When the ON / OFF operation is completed, And outputs a branch output normalization control signal so that signal transmission to the connected adjacent node is normalized.

Images