KR20070077934A - Apparatus and method for interface between channel card and if board in a wireless communication - Google Patents

Abstract

An apparatus and a method for interfacing a channel card and an IF(Intermediate Frequency) board in a wireless communication system are provided to reduce the number of LVDS(Low Voltage Differential Signal) lines between a channel card and an IF board and also reduce complexity of a backboard. Multiplexers(640,650) receive at least one or more transmission antenna signals and combine them into a single antenna signal, and divide an input signal inputted from an IF board(680) into at least one or more reception antenna signals. MGTs(Multi Gigabit Transceivers)(660,670) convert the single antenna signal inputted from the multiplexers into an LVDS, and convert a single LVDS inputted from the IF board into a reception antenna signal and output it to the multiplexers.

Description

APAPATUS AND METHOD FOR INTERFACE BETWEEN CHANNEL CARD AND IF BOARD IN A WIRELESS COMMUNICATION}

1 is a diagram schematically illustrating a configuration of a base station using multiple antennas in a general wireless communication system;

2 is a diagram schematically illustrating an example of a transmission signal between a channel card and an IF board in a general wireless communication system;

3 is a diagram schematically illustrating an internal configuration of a channel card in a general wireless communication system;

4 is a diagram schematically illustrating a configuration of a base station using multiple antennas in a wireless communication system according to an embodiment of the present invention;

5 is a view schematically showing an example of a transmission signal between a channel card and an IF board in a wireless communication system according to an embodiment of the present invention;

Figure 6 is a schematic diagram showing the internal configuration of a channel card in a wireless communication system according to the silencing PDp of the present invention.

The present invention relates to a wireless communication system, and more particularly, to an internal interface structure of a base station using multiple antennas in a wireless communication system and a control method thereof.

Commonly used technologies for providing data services to users in the current wireless communication environment include CDMA2000 Code Division Multiple Access 2000 1x Evolution Data Optimized (GPDMA), General Packet Radio Services (GPRS), and Universal Mobile Telecommunication Service (UMTS). And wireless LAN technologies such as 2.5 generation or 3 generation cellular mobile communication technology, and IEEE (Institute of Electrical and Electronics Engineers) 802.11 wireless local area network (hereinafter referred to as "LAN"). Divided into.

In addition, various short-range wireless access technologies, such as IEEE 802.16 based wireless LAN, have appeared in parallel with the evolution of the mobile communication technologies. The short-range wireless access technologies replace wired communication networks such as cable modems or digital subscriber line (xDSL) in hot spot areas or home network environments such as public places or schools, As an alternative for providing high speed data service in a wireless environment.

However, when providing a high-speed data service over the wireless LAN described above, there are limitations in providing public network services to users due to radio interference, as well as extremely limited mobility and narrow service area.

Therefore, efforts to overcome the above limitations have been made at various angles. For example, researches on portable Internet technologies that complement the advantages and disadvantages of cellular mobile communication systems and wireless LANs are being actively conducted. As a representative example of the portable Internet technology, which is currently being standardized and developed, researches on a wireless broadband Internet (WiBro) system are being actively conducted. The WiBro system can provide high-speed data services in mobile environments such as indoor / outdoor stop environment, walking speed, and medium / low speed (about 60 km / h) using various types of mobile terminals (MS).

On the other hand, in recent years, there is a need for a technology that can increase the transmission speed in order to provide a higher quality service in accordance with the rapid increase in demand for wireless communication, expansion of the Internet and rapid development of communication technology. In addition, there is a need for additional equipment of the base station due to the limitation of frequency resources, limitations in multimedia communication such as moving pictures, and increasing service radius. However, the additional equipment of such a base station is not only difficult to implement, but also incurs a large cost for the additional equipment. Therefore, there is a need for a technology for solving a problem such as the need for a plurality of base stations. As such technology, a system using multiple antennas, for example, a smart antenna system, is applied.

The principle of the smart antenna system is a method of concentrating radio waves in a direction of a desired subscriber by using spatial multiplexing, and reducing and transmitting an interference signal of another subscriber. This makes it possible to efficiently use the limited radio resources of the existing communication system. That is, when using a conventional omni-directional antenna, not only a mobile station (MS) but also a signal from an unwanted mobile terminal is transmitted and received. However, the smart antenna system can suppress the interference signal by transmitting and receiving only the signal from the desired mobile terminal.

On the other hand, the base station of the WiBro system as described above, for example, a radio access station (Radio Access Station, hereinafter referred to as "RAS") supports the performance of the system and various interfaces, and the intermediate frequency ( Intermediate Frequency (IF) is used as a Field Programmable Gate Array (FPGA) board using Xilinx MGT (Multi-Gigabit Transceiver). In addition, in the WiBro RAS system, an interface structure between a channel card and an IF board is connected to a full mesh structure. Since the interface structure will be described later, a detailed description thereof will be omitted.

In the WiBro RAS system, signal data transmission and reception between the channel card and the IF board is typically transmitted regardless of the state of the channel card. However, if the data is transmitted as described above without the channel card mounted, a noise signal for the surrounding channel acts as an interference through the full mesh path on the IF board and the channel card. As a result, system performance may be degraded.

In addition, when the channel card is not mounted as described above, floating data is generated when data is transmitted and received between the channel card and the IF board, and the performance of the channel is degraded due to the floating data. do. This problem can occur very seriously in systems with smart antennas. Therefore, a method for solving such a problem is required.

Accordingly, an object of the present invention is to provide an efficient interface structure within a base station and a method of controlling the same in a wireless communication system.

Another object of the present invention is to provide an interface structure and a control method thereof that can reduce complexity by simplifying the connection between a channel card and an IF board in a wireless communication system.

It is still another object of the present invention to provide an interface structure and a control method thereof in which the number of LVDS lines between a channel card and an IF board in a wireless communication system can be reduced, thereby reducing the complexity of a backboard.

An apparatus according to an embodiment of the present invention for achieving the above objects; In an interface device between a channel card and an intermediate frequency (IF) board in a wireless communication system, a structure between at least one channel card and an IF board for antenna signal processing is one-to-one correspondence in one channel card and one IF board It is formed of an interface structure for processing one sector, and each of the channel cards, input at least one or more transmit antenna signals to combine into a single antenna signal, the input signal input from the IF board at least one or more receiving antenna signals A multiplexer separated by a signal, and converts one antenna signal coupled and input from the multiplexer into a low voltage differential signal (LVDS) signal, and converts one LVDS signal input from the IF board into a received antenna signal It includes MGT (Multi Gigabit Transceiver).

Method according to an embodiment of the present invention for achieving the above objects; In a method for controlling an interface between a channel card and an intermediate frequency (IF) board in a wireless communication system, at least one channel card and an IF board structure for antenna signal processing correspond one-to-one to one channel card and one IF board And an interface structure for processing one sector in and combining at least one transmit antenna signal into one antenna signal and converting the combined antenna signal into a low voltage differential signal (LVDS) signal. Converting and transmitting to the IF board.

Method according to an embodiment of the present invention for achieving the above objects; In a method for controlling an interface between a channel card and an intermediate frequency (IF) board in a wireless communication system, at least one channel card and an IF board structure for antenna signal processing correspond one-to-one to one channel card and one IF board And an interface structure for processing one sector in a, converting one low voltage differential signal (LVDS) signal input from the IF board into an antenna signal, and receiving a plurality of received antenna signals Separating the antenna signals and transmitting them to each receiving antenna processor.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

Prior to the description of the present invention, the terms or words used in the specification and claims described below should not be construed as being limited to the ordinary or dictionary meanings, the inventors in their best way For the purpose of explanation, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention on the basis of the principle that it can be appropriately defined as the concept of term. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

The present invention relates to a broadband wireless access (BWA) communication system. In particular, embodiments of the present invention will be described by taking a wireless broadband Internet (WiBro) system hereinafter referred to as "WiBro". However, the present invention is not limited thereto, and therefore, the present invention can be applied to any communication system using a multiple access method.

In an embodiment of the present invention, an intermediate frequency mounted on a base station including a smart antenna (SA) in the WiBro system, for example, a radio access station (hereinafter referred to as RAS), may be used. Hereinafter, referred to as 'IF' board, for example, an interface scheme for efficient data transmission between a HPi intermediate frequency board assembly (HIFA) and a channel card (e.g., HEPA) To provide. That is, the proposed embodiment of the present invention proposes a scheme and an interface for efficiently configuring a channel card and an IF board in a multi-antenna environment.

First, a configuration of a base station using multiple antennas in a general wireless communication system such as a WiBro system will be described.

1 is a diagram schematically illustrating a configuration of a base station using multiple antennas in a general wireless communication system. 2 is a diagram schematically showing an example of a transmission signal between the channel card and the IF board according to FIG.

First, referring to FIG. 1, the structure of the general base station includes a plurality of channel cards 110, for example, HEPA # 0, HEPA # 1, and HEPA # 2, and a plurality of IF boards 120, for example, HIFA. # 0, HIFA # 1, HIFA # 2, HIFA # 3, HIFA # 4, a plurality of amplifiers 130, for example HPi (HPi Power Amplifier Unit) # 0 to HPAU # 11, and a plurality of radio frequencies Frequency (hereinafter, referred to as RF) boards 140, for example, HPF Front-end Receiver Unit (HFRU) # 0 to HFRU # 6, CBM (CaliBration Module) 150 and a plurality of antennas Field 160. In this case, the CBM is a module that combines 12 antenna data to return to HFRU # 6 for calibration and distributes the signal received from HFRU # 6 to 12 antennas.

As shown in FIG. 1, the general wireless communication system, for example, a WiBro system, has a structure of processing 1FA / 3 sectors. In general, a communication system may use multiple antennas as shown in FIG. 1 to increase processing capacity. As shown in FIG. 1, when the multiple antenna 160 is used, the channel card 110 processes four antennas for one sector.

In addition, the IF board 120 in FIG. 1 shows a structure for processing three antennas. Therefore, two IF boards, for example, HIFA # 0 and HIFA # 1, are required to process four antenna signals transmitted from the channel card 110, for example, HEPA # 0.

That is, FIG. 1 shows a connection structure for processing 12 antennas in 3 sectors. In this case, in order to process 12 antennas as shown in FIG. 1, three channel cards 110, for example, HEPA # 0 to HEPA # 2 and four IF boards 120, for example, HIFA # 0 to HIFA # 4 are required. Do. In addition, the configuration connected to each IF board in each channel card 110 is configured differently corresponding to the position where the channel card 110 is mounted.

In FIG. 1, each of the three HEPA # 0, HEPA # 1 and HEPA # 2, and the interface with HIFA # 4 is a path for calibration from the smart antenna to the amplifier, converter and cable of the base station system. Indicates a path for measuring distortion. When transmitting a specific value for each antenna, CBM combines 12 antennas and returns them to HFRU # 6 and returns them to HEPA # 0, # 1, # 2 through HIFA # 4. HEPA takes the returned value, measures the distortion of the returned data with respect to the sent data, and compensates the transmitted data by the distorted value. The reception path sends data specific to HIFA # 4, transmits from HIFA # 4 to HFRU # 6, sends HFRU # 6 to CBM, and distributes them to 12 antennas at CBM. The distortion of the reception path is measured using the values returned to the 12 reception paths, and the received data is compensated by the distorted value.

Next, referring to FIG. 2, a signal transmission connected to the IF board 120 in the channel card 110 performs a low voltage differential signal (LVDS) transmission, and the LVDS transmission is performed through one antenna. Send the data.

3 is a diagram schematically illustrating an internal configuration of a channel card in a general wireless communication system. In particular, FIG. 3 illustrates an internal configuration of a field programmable gate array (FPGA) of the channel card.

Referring to FIG. 3, one channel card 300, for example, HEPA # 0 illustrated in FIG. 1, interfaces with two IF boards, for example, HIFA # 0 350 and HIFA # 1 360. 3 illustrates an internal configuration of an FPGA that interfaces with an IF board by receiving data from an IF board and four antennas from a channel card. The internal configuration of the FPGA includes a plurality of buffers 301 to 311, a plurality of antenna controllers 320 and 330, and a plurality of multi-gigabit transceivers (MGTs) 340. Here, the MGT 340 represents a port for transmitting and receiving an LVDS signal as shown in FIG. 2 through the antennas 320 and 330.

As illustrated in FIG. 3, when one data is input to the MGT block 340 through an internal antenna 320 in a transmission block including the buffers 301 and 303, the MGT block 340 may be configured to transmit the data. The data is converted into an LVDS signal and transmitted to the HIFA # 0 350 and the HIFA # 1 360. Then, the HIFA # 0 350 and the HIFA # 1 360 process the LVDS signal received from the MGT block 340.

Also, when the HIFA # 0 350 and the HIFA # 1 360 transmit an LVDS signal received from the outside to the MGT block 340, the MGT block 340 converts the LVDS signal into a normal signal. The normal signal is transmitted to an reception block including the buffers 305 to 311 through an internal antenna 330.

In the general wireless communication system as described above, the configuration for connecting the channel card and the IF board is initially set at the upper level. Therefore, there is a problem in that the system does not operate normally when the position of the channel card or the IF board is changed or a state change occurs such as demounting / mounting.

In addition, the LVDS transmission is generally capable of 1Gbps transmission, and since the FPGA structure as described above only transmits data of one antenna, it can be seen that only about 1/3 of the transmission capability is used. At this time, since 12 antenna data must be transmitted in the structure as shown in FIG. 1, 12 LVDS lines are used. This structure causes an increase in the number of LVDS pins in the FPGA of the channel card and the IF board, and the price of the FPGA increases.

Therefore, in the embodiment of the present invention described below, by processing the four antennas in the IF board, it is possible to transmit two antenna data to one LVDS line, thereby efficiently configuring the channel card and IF board, By simplifying the connection between the channel card and the IF board.

To this end, an embodiment of the present invention proposes a structure for processing four antennas in the IF board, and also the structure that can transmit the data transmission of the four antennas between the channel card and the IF board separately in two LVDS lines Suggest.

4 is a diagram schematically illustrating a configuration of a base station using multiple antennas in a wireless communication system according to an embodiment of the present invention. 5 is a diagram schematically showing an example of a transmission signal between the channel card and the IF board according to FIG.

First, referring to FIG. 4, a structure of a base station according to an embodiment of the present invention includes a plurality of channel cards 410, for example, HEPA # 0, HEPA # 1, and HEPA # 2, and a plurality of IF boards ( 420) For example, HIFA # 0, HIFA # 1, HIFA # 2 and HIFA # 4, a plurality of amplifiers 430 such as HPi (HPi Power Amplifier Unit) # 0 to HPAU # 11, and a plurality of RF boards 140, for example, HPF front-end receiver unit (HFRU) # 0 to HFRU # 6, a CBM (CaliBration Module) 450, and a plurality of antennas 460.

In general, a portable Internet system using a multiple antenna scheme processes four antennas in one sector. Therefore, one channel card handles one sector and processes four antennas. Therefore, in a multi-antenna system, 12 antennas are processed in 3 sectors.

Accordingly, in the embodiment of the present invention, as shown in FIG. 4, four antennas are processed in the IF board, through which one channel card and one IF board process one sector. Therefore, as shown in FIG. 4, the connection between the channel card and the IF board can be efficiently configured.

Meanwhile, in a typical wireless communication system, only one antenna can transmit data on an LVDS line between a channel card and an IF board. That is, as one sector was processed using one channel card and two IF boards, data was transmitted to one LVDS line for each antenna.

In contrast, the embodiment of the present invention proposes a structure in which the data of the four antennas of the channel card are connected to one IF board, so that the maximum data can be transmitted to the LVDS line. That is, assuming that 1Gbps LVDS capacity processes data of two antennas, according to the embodiment of the present invention, two data can be transmitted on one LVDS line.

Next, referring to FIG. 5, since the period of the portable Internet system is 10 MHz and the speed of the system is 50 MHz, 10 MHz is divided into five sections and a sync signal is allocated to the first section. The data I and Q signals of antenna 1 are allocated to the second and third sections. In the fourth and fifth sections, data I and Q signals of antenna 2 are allocated. Accordingly, the signal transmission connected to the IF board 420 in the channel card 410 performs LVDS transmission, and the LVDS transmission transmits data through two antennas.

6 is a view schematically showing the internal configuration of a channel card in a wireless communication system according to an embodiment of the present invention. In particular, FIG. 6 illustrates an internal configuration of a field programmable gate array (FPGA) of the channel card.

Referring to FIG. 6, one channel card 600, for example, HEPA # 0 illustrated in FIG. 4 interfaces with one IF board, for example, HIFA # 0 680. The internal configuration of the FPGA includes a plurality of buffers 601 to 611, a plurality of antenna controllers 620 and 630, at least one or more multiplexers 640 and 650, and a number of MGTs corresponding to the multiplexers. Multi Gigabit Transceiver) (660, 670). Here, the MGTs 660 and 670 represent ports for transmitting and receiving LVDS signals as shown in FIG. 5 through the antennas 620 and 630.

As shown in FIG. 6, an embodiment of the present invention includes multiplexers 640 and 650 for generating two antenna data in front of the MGT 660 and 670 as signals as shown in FIG. The multiplexers 640 and 650 combine two antenna data into one LVDS signal and transmit the same to the HIFA # 0 680. In addition, the multiplexers 640 and 650 separate the data of the two antennas from the LVDS signal received by the HIFA # 0 680. The function of separating into two antennas recognizes a sync signal from the received signal, separates the I and Q signals of antenna 1 sequentially after the recognized sync signal, and then I, Q of antenna 2. Isolate the signal.

The MGTs 660 and 670 convert one piece of antenna data coupled and output from the multiplexer into an LVDS signal for transmission to the IF board and transmits the data to the IF board 680, respectively.

As described above, in the detailed description of the present invention has been described with respect to specific embodiments, various modifications are of course possible without departing from the scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below, but also by the equivalents of the claims.

As described above, according to the apparatus and method for interface between a channel card and an IF board in the wireless communication system of the present invention proposed in the present invention, the interface between the channel card and the IF board in a base station in the wireless communication system can be efficiently and reduced in complexity. Has an advantage. In addition, the number of LVDS lines between the channel card and the IF board in the wireless communication system can be reduced, thereby reducing the complexity of the backboard. In addition, reducing the number of LVDS lines between the channel card and the IF board has the advantage of reducing interference between LVDS lines.

In addition, the efficient interface configuration between the channel card and the IF board simplifies the connection between the channel card and the IF board. In addition, the number of LVDS pins can be reduced in FPGAs on channel cards and IF boards, which has the advantage of lowering the cost of FPGAs.

Claims (11)

An interface device between a channel card and an intermediate frequency (IF) board in a wireless communication system, At least one channel card and the structure between the IF boards for antenna signal processing are formed in an interface structure that processes one sector in one channel card and one IF board in a one-to-one correspondence. A multiplexer for inputting at least one transmit antenna signal into a single antenna signal and separating the input signal input from the IF board into at least one receive antenna signal; MGT (Multi GT) converts one antenna signal coupled and input from the multiplexer into a low voltage differential signal (LVDS) signal, converts one LVDS signal input from the IF board into a reception antenna signal, and outputs the received antenna signal to the multiplexer Interface device including Gigabit Transceiver). The method of claim 1, Wherein the multiplexer is located in front of the MGT and combines two transmit antenna signals into one antenna signal to transmit to the MGT. The method of claim 1, And the multiplexer separates one LVDS signal received from the IF board into two receive antenna signals. The method of claim 1, And the multiplexer divides the signal into at least one receiving antenna signals through synchronization of a received signal received from the IF board and input through the MGT. The method of claim 1, The multiplexer recognizes a sync signal from a received signal, sequentially separates I and Q signals of a first antenna after the recognized sync signal, and then separates I and Q signals of a second antenna. Interface device characterized in that. In the method of controlling the interface between a channel card and an intermediate frequency (IF) board in a wireless communication system, The structure between at least one channel card and the IF boards for antenna signal processing includes an interface structure that processes one sector in one channel card and one IF board in a one-to-one correspondence. Combining at least one transmit antenna signal into one antenna signal, and And converting the combined antenna signal into a low voltage differential signal (LVDS) signal and transmitting the signal to the IF board. The method of claim 6, The combining process includes combining two transmit antenna signals into one antenna signal and transmitting the same to one multi-gigabit transceiver (MGT). In the method of controlling the interface between a channel card and an intermediate frequency (IF) board in a wireless communication system, The structure between at least one channel card and the IF boards for antenna signal processing includes an interface structure that processes one sector in one channel card and one IF board in a one-to-one correspondence. Converting one low voltage differential signal (LVDS) signal input from the IF board into an antenna signal; And dividing the converted one antenna signal into a plurality of receiving antenna signals and transmitting the received antenna signals to each receiving antenna processor. The method of claim 8, The separating may include separating the one antenna signal converted and input into two receiving antenna signals. The method of claim 8, The separating may include separating into at least one receiving antenna signals through synchronization of an input received signal. The method of claim 8, The separating may include: recognizing a sync signal from a received signal; Separating the I and Q signals of the first antenna sequentially after the recognized synchronization signal; And separating the I and Q signals of the second antenna after separating the first antenna signal.

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