KR101394610B1 - Server and method for load balancing - Google Patents

Abstract

Disclosed is a server apparatus of a specific hierarchy connected to a digital unit for receiving a baseband signal from a wireless unit located in a remote cell and processing the baseband signal by protocol layer. The server device is a master server for managing a plurality of slave servers, and transmits a request message for changing a server for performing call processing of a specific user to another server from the master server and a plurality of slave servers, A requesting unit for transmitting the acknowledgment message to the layer server; A server management unit for assigning a server to perform call processing of the specific user to the another server when the request unit receives the approval message; And an acknowledgment unit for transmitting an acknowledgment message when a request message is received from a server of an adjacent upper layer or lower layer to inform that a server for performing call processing of a specific user is changed.

Description

TECHNICAL FIELD [0001] The present invention relates to a server apparatus for load balancing,

The present invention relates to a server apparatus for load balancing and a method thereof.

Generally, a communication base station is composed of a digital unit (DU) for processing a digital signal and a radio unit (RU) for processing a radio signal. Recently, a virtual radio network in which a plurality of digital units are integrated into a digital unit center by separating a radio unit and a digital unit has been proposed.

Here, each radio unit transmits a baseband signal to the digital unit, and the digital unit processes the received baseband signal layer by layer. To this end, the digital unit is connected to each server that performs processing of each layer.

However, in the past, when a load is concentrated on a server that performs processing of a specific layer, there is no method for processing the load.

For example, the digital unit is connected to a server that performs processing of an RRC (Radio Resource Control) layer, and requests RRC processing of a baseband signal received by the radio unit to the server. However, in this case, when the call connection of the users is concentrated and the RRC processing request is congested, the load of the server is considerable, but there is no solution to solve it.

Korean Patent Publication No. 2002-0011180 (published on February 8, 2002), a relay device between a digital unit of a base station and a radio frequency unit Korean Patent Publication No. 2009-0116112 (published on Jan. 11, 2009), a method of controlling transmission and reception operations in a separate base station, and a digital unit and a separate base station

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a server apparatus and method for load balancing servers for processing baseband signals received from a wireless unit by a digital unit.

According to one aspect of the present invention, a server apparatus is provided. The server apparatus includes a plurality of slave servers, each of which is connected to a digital unit for receiving a baseband signal from a wireless unit located in a remote cell and processes the baseband signal by protocol layer, And transmits a request message for changing a server for performing call processing of a specific user from the master server and the plurality of slave servers to another server in an upper layer and a lower layer server in the adjacent upper layer, A request receiving unit; A server management unit for assigning a server to perform call processing of the specific user to the another server when the request unit receives the approval message; And an acknowledgment unit for transmitting an acknowledgment message when a request message is received from a server of an adjacent upper layer or lower layer to inform that a server for performing call processing of a specific user is changed.

According to one aspect of the present invention, a load balancing method is provided. The method includes a load distribution method for a server apparatus responsible for processing in a specific layer of a baseband signal received from a wireless unit, wherein the server apparatus is a master server for managing a plurality of slave servers, Determining whether a master server or a slave server is in an overload state; The server device transmits a request message to a master server of an adjacent lower layer to change a server to perform call processing of a specific user to another server; Receiving an acknowledgment message from a master server of the lower layer; Transmitting a request message to a master server of an upper layer adjacent to the server apparatus to change a server for performing call processing of a specific user to another server; And allocating a server for performing call processing of the specific user to the other server when the grant message is received from the master server of the upper layer.

According to the embodiment of the present invention, since connection is made to the master server of each layer at initial call connection, connection delay due to load distribution can be minimized.

In addition, since there are a plurality of slave servers, the load can be distributed to a slave server having a small load among them, so that all the processing resources can be efficiently used and used.

1 is a configuration diagram of a virtualized wireless network to which an embodiment of the present invention is applied.
2 is a connection configuration diagram of L1, L2, and L3 according to an embodiment of the present invention.
3 shows a server configuration of a control plane according to an embodiment of the present invention.
4 illustrates a server configuration of a user plane according to an embodiment of the present invention.
5 is a conceptual diagram illustrating server load balancing according to an embodiment of the present invention.
6 is a flowchart illustrating a request and an approval process for server replacement according to an embodiment of the present invention.
7 is a block diagram showing a configuration of a master server of each of an L2 layer and an L3 layer according to an embodiment of the present invention.
8 is a block diagram illustrating a configuration of an RRC master server according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Also, the term "part" in the description means a unit for processing at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software.

Hereinafter, a server apparatus and method for load balancing according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a configuration diagram of a virtualized wireless network to which an embodiment of the present invention is applied.

1, a virtualized wireless network includes a plurality of radio units (RUs) 100, a digital unit (DU) center 200, an IP network 300, and a core system 400 do.

The communication base station generally comprises a digital unit 201 for processing a digital signal and a wireless unit 100 for processing a wireless signal. According to the virtualized wireless network of FIG. 1, the wireless unit 100 and the digital unit 201 And integrates the plurality of digital units 201 into the digital unit center 200. The wireless unit 100 is installed in a service area, that is, a cell site. For example, a radio unit 100 is installed in each cell of an LTE (Long Term Evolution) network, a cell of a High Speed Packet Access (HSPA) + network, and a cell of a WiMAX (Worldwide Interoperability for Microwave Access) .

The digital unit center 200 includes a digital unit 201 for processing a signal received from a wireless unit 100 installed in each network, LTE software, HSPA + software, and WiMAX software on an open hardware platform. At this time, SDR (Software Defined Radio) technology can be used.

In addition, the digital unit center 200 is connected to the core system 400 via the IP network 300. At this time, the core system 400 is connected to the radio access network, that is, the digital unit center 200, and is composed of elements for responding to a connection with an external network (not shown).

Each of the radio units 100 transmits a baseband signal to the digital unit 201 and converts a digital signal received from the digital unit 201 into an RF (Radio Frequency) signal according to a frequency band And an RF amplifier for transmitting and receiving signals to and from the antenna.

The digital unit 201 processes the received baseband signal in three layers (L1, L2, L3).

2 is a connection configuration diagram of L1, L2, and L3 according to an embodiment of the present invention.

Referring to FIG. 2, a plurality of L1 modems 500 are connected to a plurality of L2 servers 700 and a plurality of L3 servers 800 through a switch 600.

At this time, the L1 modem 500 is mounted on the digital unit 201 and takes charge of L1 layer processing. L1 is a physical layer, and the L1 modem 500 is equipped with dedicated hardware (H / W) for processing L1. In this dedicated hardware (H / W), the baseband signal received from the radio unit 100 is processed.

Here, the physical layer handles data transmission over the wireless channel with the wireless unit 100. [

In addition, the plurality of L2 servers 700 and the plurality of L3 servers 800 comprise a plurality of servers for processing the L2 layer and the L3 layer, respectively.

In the LTE system, the L2 layer includes a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, and a Packet Data Convergence Protocol (PDCP) layer, and the L2 server 700 includes a MAC server, PDCP server.

The MAC layer controls the radio link provided by the physical layer, i.e., L1, and selects an appropriate transport channel to transmit data from the upper layer, i.e., the RLC layer, and transmits the data over the radio link.

The RLC layer is located at the upper layer of the MAC layer and supports reliable transmission of data.

The PDCP layer is used only in the packet switching area. The IP header compresses and decompresses the IP header to compress the header of the IP packet so as to increase the transmission efficiency of the packet data in the wireless channel, transmits the user data, and maintains the sequence number for the radio bearer do.

In the LTE system, the L3 layer includes an RRC (Radio Resource Control) layer, a GTP (General Tunneling Protocol) layer, and an S1AP (S1 Application Part) layer. The L3 server 800 includes an RRC server, a GTP server, Server.

The RRC layer generates and transmits a message for controlling resources related to the radio frequency. It also performs efficient resource allocation for users and data, and is located in the RNC (Radio Network Center).

The GTP layer is used for transmission and reception of the user plane between the RNC of the existing 3GPP and the Mobile Switching Center (MSC). End users of the GSM or WCDMA network can continue to access the Internet at the Gateway GPRS Support Node (GGSN), move the subscriber's data from the subscriber's Serving GPRS Support Node (SGSN) To the GGSN.

The S1AP layer is a signaling protocol specified in 3GPP TS 36.413 and includes functions defined by the E-UTRAN radio network for the S1 interface, which is a signaling protocol between the base station and the gateway.

Meanwhile, the data to be transmitted is divided into two areas according to the type, namely, a user plane and a control plane. The user plane is a region in which traffic information of a user such as voice or IP packet is transmitted, It is the area where control information such as network interface or call maintenance and management is transferred.

At this time, the data transmitted by the RRC layer is included in the control plane, and the data transmitted through the PDCP layer and the BMC layer are included in the user plane. The RLC layer belongs to the control plane when it is connected to the RRC layer and belongs to the user plane in the remaining cases.

FIG. 3 shows a server configuration of a control plane according to an embodiment of the present invention, and FIG. 4 shows a server configuration of a user plane according to an embodiment of the present invention.

At this time, the servers that process each of the L2 layer and the L3 layer are composed of a master server and a plurality of slave servers, for example, three slave servers.

Referring to FIG. 3, the physical layer (PHY) and the MAC layer are fixed cell by cell. That is, the PHY of the cell 1 is connected to the MAC server 1. The physical layer PHY of the cell 2 is connected to the MAC server 2. The physical layer PHY of the cell 3 is connected to the MAC server 3. The physical layer PHY of the cell 4 is connected to the MAC server 4.

The server of the RLC layer, which is the upper layer of the MAC layer, comprises an RLC master server, an RLC slave server 1, an RLC slave server 2, and an RLC slave server 3.

The server of the RRC layer, which is the upper layer of the RLC layer, comprises an RRC master server, an RRC slave server 1, an RRC slave server 2, and an RRC slave server 3.

The S1-AP layer server, which is the upper layer of the RRC layer, is composed of the S1-AP master server, the S1-AP slave server 1, the S1-AP slave server 2, and the S1-AP slave server 3.

At this time, when the initial call is connected, call connection is made to the master server of each layer. That is, all of the MAC servers MAC1, MAC2, MAC3, and MAC4 access the RLC master server once. The RLC master server is connected to the RRC master server, and the RRC master server is connected to the S1-AP master server.

Referring to FIG. 4, the physical layer (PHY) and the MAC layer are fixed on a cell-by-cell basis as in FIG. That is, the PHY of the cell 1 is connected to the MAC server 1. The physical layer PHY of the cell 2 is connected to the MAC server 2. The physical layer PHY of the cell 3 is connected to the MAC server 3. The physical layer PHY of the cell 4 is connected to the MAC server 4.

The server of the RLC layer, which is the upper layer of the MAC layer, comprises an RLC master server, an RLC slave server 1, an RLC slave server 2, and an RLC slave server 3.

The GTP layer server, which is an upper layer of the RLC layer, is composed of a GTP master server, a GTP slave server 1, a GTP slave server 2, and a GTP slave server 3.

At this time, when the initial call is connected, all the MAC servers MAC1, MAC2, MAC3, and MAC4 access the RLC master server once. Then, the RLC master server connects to the GTP master server.

However, each of the L2 and L3 layer master servers manages a plurality of slave servers in the corresponding layer, and distributes the load to the slave servers when the server is overloaded. In addition, if the overload of a specific slave server occurs by monitoring the load state of the slave servers, the load is distributed to another slave server. This will be described with reference to FIG.

5 is a conceptual diagram illustrating server load balancing according to an embodiment of the present invention.

Referring to FIG. 5, if the RLC master server determines that the RLC master server is overloaded, it may distribute the load to a specific slave server, for example, the RLC slave server 3. Then, the MAC server connects to the RLC slave server 3, and the RLC slave server 3 connects to the RRC master server.

In order to distribute the load of the server in this manner, a request and approval process for replacing the server between the servers of adjacent layers must be preceded, which will be described with reference to FIG.

6 is a flowchart illustrating a request and an approval process for server replacement according to an embodiment of the present invention.

Referring to FIG. 6, if the RLC master server determines that it is in an overload state and distributes the load to the slave server, the RLC master server accesses the slave server 2 with a call connection of a specific user (User A) The server is requested to change (S101). When the approval of the change request is received from the MAC server (S103), the call connection of the specific user (User A) to the adjacent upper layer, that is, the RRC master server, is requested from the slave server 2 (S105).

At this time, when the change approval is received from the RRC master server (S107), the call connection of the specific user (User A) will be made from the MAC server -> RLC slave server 2 -> RRC master server.

Although the RLC server has been described with reference to FIG. 6, the request and approval process of FIG. 6 can be performed in all the master servers of the L2 and L3 layers.

7 is a block diagram showing a configuration of a master server of each of an L2 layer and an L3 layer according to an embodiment of the present invention. At this time, the configuration of the master servers of the L2 and L3 layers excluding the RRC server is shown.

7, the master server 900 includes a server management unit 901, a load monitoring unit 903, a request unit 905, and an approval unit 907.

Here, the server management unit 901 manages information of a plurality of slave servers and manages server numbers used by each user. If it is determined that the load of the master server 900 is overloaded, the server to be used by specific users is assigned to one of the plurality of slave servers, and the assigned user ID is transmitted to the corresponding slave server.

The load monitoring unit 903 monitors the load state of the master server 900 and the load states of the plurality of slave servers, determines whether the load is overloaded, and provides the server management unit 901 with the load.

When the server management unit 901 decides to change a server to be used by a specific user, the request unit 905 requests the master server of the adjacent hierarchy to change the server of the specific user to the slave server determined by the server management unit 901 (Request) message, and receives an acknowledgment message. Here, the request message includes the ID of the specific user.

At this time, when the request unit 905 receives the grant message from the master server of the adjacent layer, the server management unit 901 changes the server of the specific user. The server management unit 901 transmits the ID of the specific user to the changed slave server.

The acknowledgment unit 907 transmits an acknowledgment to the specific user from the master server of the adjacent layer when a request message requesting connection from the slave server of the adjacent layer is received.

8 is a block diagram illustrating a configuration of an RRC master server according to an embodiment of the present invention.

8, the RRC master server 1000 includes a server management unit 1001, a load monitoring unit 1003, a request unit 1005, an approval unit 1007, and a user information management unit 1009.

Here, the server management unit 1001, the load monitoring unit 1003, the request unit 1005, and the approval unit 1007 are the same as the configuration of the master server of FIG. 7, and thus description thereof is omitted.

When the call is connected, the user information management unit 1009 informs the user terminal (not shown) of the number of the master server 900 of each layer to be used for each user. That is, since the user A initially uses the master server of all layers, it provides the information of the master server of each layer that processes different protocols for each data flow.

At this time, although the master server 900 is shown as one, there may be a plurality of master servers 900, and in this case, the number of the master server 900 to be used by the user is provided.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (6)

A server apparatus in a specific layer for processing a baseband signal by a protocol layer, the server apparatus being connected to a digital unit for receiving a baseband signal from a wireless unit located in a remote cell,
Wherein the server device is a master server for managing a plurality of slave servers,
A request unit for transmitting a request message for changing a server for performing call processing of a specific user to another server among the master server and the plurality of slave servers to a server of an upper layer and a lower layer server of an adjacent upper layer and receiving an approval message;
A server management unit for assigning a server to perform call processing of the specific user to the another server when the request unit receives the approval message;
An acknowledgment unit for transmitting an acknowledgment message when a request message is received from a server of an adjacent upper layer or lower layer to inform that a server for performing call processing of a specific user is changed;
And a load baluner for monitoring the load state of the master server and the plurality of slave servers to detect overload,
The server management unit,
When the master server or the plurality of slave servers are overloaded, determines a different server to perform call processing of a specific user to be processed in the master server or the plurality of slave servers, and transmits a request message And transmits the request to the requesting unit. delete The method according to claim 1,
The master server is a master server of an RRC (Radio Resource Control) layer,
The master server of the Radio Resource Control (RRC)
And provides master server information of each layer for each data flow to a connected user terminal. The method according to claim 1,
The digital unit includes a modem for performing physical layer processing of the baseband signal and is connected to each server for processing the baseband signal by the first layer and the second layer,
The first layer includes a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, and a Packet Data Convergence Protocol (PDCP) layer. The second layer includes a Radio Resource Control (RRC) layer, a General Tunneling Protocol layer, and an S1 Application Part (S1AP) layer,
Wherein the master server comprises a server for processing the first layer and a server for processing the second layer,
Wherein the physical layer and the MAC layer are fixed on a cell-by-cell basis. A load distribution method for a server apparatus that handles processing in a specific layer of a baseband signal received from a wireless unit,
The server device is a master server that manages a plurality of slave servers and is connected to a digital unit,
Determining whether a master server or a slave server responsible for call processing of a specific user is overloaded;
The server device transmits a request message to a master server of an adjacent lower layer to change a server to perform call processing of a specific user to another server;
Receiving an acknowledgment message from a master server of the lower layer;
Transmitting a request message to a master server of an upper layer adjacent to the server apparatus to change a server for performing call processing of a specific user to another server; And
Allocating a server to perform call processing of the specific user to the other server when the grant message is received from the master server of the upper layer
≪ / RTI > 6. The method of claim 5,
Receiving a request message from a server of an adjacent upper layer or lower layer to inform that a server to perform call processing of a specific user is changed; And
Transmitting an acknowledgment message to the server of the upper layer or the lower layer
≪ / RTI >

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