KR20060046946A - Apparatus for duplexing switching of base transceiver station in mobile communication system - Google Patents

Abstract

The present invention is to provide a redundant switching device of the base station in a mobile communication system, GPS receiving a satellite signal, a master board for receiving and processing the signal from the GPS, receiving the signal processed by the master board to process the channel A DU basic self including a channel card to perform and performing digital signal processing at a base station of a mobile communication system; A master board daisy-chained with the master board of the DU basic shelf, and a channel card connected with the master board to perform channel processing, and a DU extension shelf for performing digital signal processing at a base station of a mobile communication system. By including the configuration, it is possible to generate and supply a system clock to the basic shelf and the expansion shelf when the DU is expanded, and to perform the redundant switching stably.

Description

Apparatus for duplexing switching of base transceiver station in mobile communication system

1 is a block diagram of a redundant switching device of a base station in a conventional mobile communication system,

FIG. 2 is a detailed block diagram illustrating a connection of a digital unit of a base station in FIG. 1.

3 is a block diagram of a redundant switching device of a base station in a mobile communication system according to the present invention,

4 is a block diagram showing the connection of the basic shelf and the extended shelf of the digital unit in FIG.

FIG. 5 is a detailed block diagram illustrating a connection of a digital unit of a base station in FIG. 3.

Explanation of symbols on the main parts of the drawings

100, 110, 120: Digital unit (DU)

101: DU Basic Self Masterboard A

102: DU Basic Self Masterboard B

103-106, 113-116, 123-126: channel card

107: GPS

111, 121: Master Board A of DU Expansion Self

112, 122: Master Board B of DU Expansion Self

211, 231: control unit

212, 213, 232, 233: system clock generator

214, 215, 234, 235: PLL control unit

216, 217, 236, 237: VCXO

218, 219, 238, 239: PLL

220, 240: phase comparison unit

221, 241: multiplexer

300: PDSN

400: CAN

500: BSC (control station)

610, 620, 630: RFU

The present invention relates to a redundant switching device of a base transceiver station (BTS) in a mobile communication system, and in particular, to reduce the cost and size of a base station, a digital unit (DU) and a radio frequency unit (RFU). In order to facilitate expansion, the base station's redundancy switching in the mobile communication system is suitable for generating and supplying system clocks to the basic self and the extended self and steadily performing the redundancy switching. Relates to a device.

In general, a mobile communication system is a communication system that targets mobile devices such as people, cars, ships, trains, and airplanes, which includes key phone systems, mobile phones (mobile phones, vehicle phones), port phones, aircraft phones, and mobile phones. Trains, cruise ships, express buses), radio calling, radiotelephony, satellite mobile communication, amateur radio, and fishing service ships.

The mobile communication system includes an AMPS (Advanced Mobile Phone Service) system using an analog method, a Code Division Multiple Access (CDMA) system using a digital method, a Wideband Code Division Multiple Access (WCDMA), and a TDMA (Time). Division Multiple Access, Time Division Multiple Access (FDMA) system, Frequency Division Multiple Access (FDMA) system, Wireless Local Loop (WLL), CDMA2000-1x, IMT-2000 (International Mobile Telecommunication in the year 2000 , Global mobile communication (GSM) systems, and GSM (Global System for Mobile communication) systems.

Thus, a base station is used in such a mobile communication system, and is a network termination device that is directly connected to a subscriber terminal by performing baseband signal processing, wired / wireless conversion, and transmission and reception of a wireless signal.

1 is a block diagram of a redundant switching device of a base station in a conventional mobile communication system.

As shown therein, the first digital unit includes a master board A 11, a master board B 12, a plurality of channel cards 13 to 16, and a GPS 17 to perform digital signal processing at a base station. DU # 0) 10; A master board A 21 connected to the master board A 11 of the first digital unit 10, a master board B 22 connected to the master board B 12 of the first digital unit 10, and A second digital unit (DU # 1) 20 having a plurality of channel cards 23 to 26 and a GPS 27 for performing digital signal processing at the base station; It is composed of a plurality of digital units (DU # n) 30 configured in the same manner as the second digital unit 20.

Here, reference numeral 1 denotes a packet data serving node (PDSN), 2 denotes a central asynchronous transfer mode network (CAN), and 3 denotes a base station controller (BSC).

Further, reference numerals 41 to 43 are a plurality of RFUs.

Therefore, the base station of the conventional mobile communication system such as CDMA2000 1x BTS is trying to reduce the size and cost to implement a low-cost or small capacity base station. This integrates boards that perform the functions of state management and control of base stations, line interfaces of BSCs and BTSs, and call processing.

In particular, the digital unit (DU) and the RF unit (RFU) are separated and the small capacity base station is basically configured according to the capacity that can be accommodated by the base station. It is expanding to accommodate many subscribers.

In the digital unit, the master board receives 10MHz, 1PPS (Precise Positioning Service) and TOD (Time of Date) from the GPS, and generates system clocks such as Chipx16 and Even Sec and supplies them to the lower device board. In order to provide continuous call service, the system is redundantly used in preparation for the system clock failure of the active board.

The digital unit's extended self-master board also receives a reference clock from GPS and generates its own system clock and supplies it to the lower device board.

FIG. 2 is a detailed block diagram illustrating a connection of a digital unit of a base station in FIG. 1.

As shown therein, the master boards A11, 21, and 31 of the DU self operating in the clock active mode in the digital units 10, 20, 30 output a clock error check / control signal. A control unit 51; A system clock generator 52 for receiving a 10 MHz, 1 PPS, TOD signal from the GPS1 and generating a system clock; The system clock of the system clock generator 52 in the DU self master board A 11 and the system clock generator 62 in the DU self master board B 12 are controlled by the controller 51. A multiplexer 53 for receiving a multiplexed clock and outputting the multiplexed clock; A PLL controller 54 which receives a system clock generated by the system clock generator 52 and controls a phase locked loop (PLL) 55; A PLL (55) for receiving a 10 MHz signal from the GPS1 and performing a PLL under the control of the PLL controller (54) and transmitting the PLL to a phase comparator (67) in the DU self master board B (11); It is composed of VCXO (Voltage Controlled Crystal Oscillators) 56 which receives the signal of the PLL 55 and performs voltage controlled oscillation and transmits it to the system clock generator 52.

In addition, the master boards B (12) (22) (32) of the DU self operating in clock standby mode in the digital units (10) (20) (30) are provided with a control unit (51) for outputting a clock error check / control signal. ; A system clock generator 62 for receiving a 10 MHz, 1 PPS, TOD signal from the GPS2 and generating a system clock; Under the control of the control unit 61, the system clock of the system clock generator 52 in the DU self master board A (11) and the system clock generator of the system clock generator 62 in the DU self master board B (12) A multiplexer 63 for receiving a clock and multiplexing the same; A PLL controller 64 for receiving the system clock generated by the system clock generator 62 and controlling the PLL 65; A PLL (65) which receives the 10 MHz signal from the GPS1 and is connected to a phase comparator (67) to perform a PLL under the control of the PLL controller (64); A VCXO 66 which receives the signal of the PLL 65 and performs voltage controlled oscillation and transmits it to the system clock generator 62; A PLL 55 in the DU self master board A 11 and a phase comparator 67 for receiving a signal from the PLL 55 in the DU self master board B 12 and comparing the phases thereof.

The operation of the prior art configured as described above will be described in detail with reference to the accompanying drawings.

First, the DU 10, 20, 30 are divided into a basic shelf and an extended shelf to facilitate expansion according to base station capacity.

At this time, each of the self master boards 11, 12, 21, 22, 31, and 32 of the DU interface with each other by interfacing with Hotlink based on ATM (Asynchronous Transfer Mode). The processing information is exchanged.

In addition, each shelf is provided with redundant GPS (17) (27) (37) 37, respectively. Therefore, the GPS of reference number 17 is composed of GPS A and GPS B, GPS A supplies a reference clock of 10 MHz, 1PPS, TOD, etc. to Master Board A (11), and GPS B is 10 MHz to Master Board B (12). Supply a reference clock such as 1PPS, TOD, etc.

In addition, reference numeral 27 is composed of GPS, GPS A and GPS B, and reference numeral 37 is composed of GPS, GPS A and GPS B, and operates in the same manner as GPS A and GPS B of reference 17.

The master boards 11 and 12 of the duplexed DU # 0 (10), the master boards 21 and 22 of the DU # 1 (20), ..., the master boards of the DU # n (30) 32 generates a synchronizer clock and supplies it to the channel card by the following procedure.

1) The PLL control unit 54 of the DU master boards A (11) (21) (31) receives 10MHz from GPS and inputs the frequency (39.3216MHz) of the VCXO 56 through a phase detector. The phase difference is determined, and a voltage corresponding to the phase difference is generated.

2) The multiplexer 53 receives 10MHz, 1PPS, and TOD from the clock and GPS of each VCXO 56 passing through the PLL 55, respectively, and generates a system clock for the channel card through a clock divider.

3) Then, the fault of each clock is checked, and the controller 51 determines the active and standby states.

4) The DU Self-Master Boards B (12) 22 (32), which also operate in clock standby, attempts to synchronize with the DU Self-Master Boards A (11) (21) (31), which operate in clock active, If the synchronization is not synchronized, the PLL controller 64 synchronizes the clocks of the actives 11, 21, and 31 again.

5) The system clock is output only from the clock active boards 11, 21, and 31, and the system clock is supplied to each channel card through a transceiver.

In addition, the clock standby boards 12, 22, and 32 do not output the system clock and are kept in synchronization with the clock active boards 11, 21, and 31. The clock active boards 11, 21, and 31 ), It operates to output the system clock to each channel card.

However, this conventional technology has the following problems.

First, in the DU used in the conventional CDMA2000 1x BTS and the like, GPS is mounted on the basic self and extended self, respectively, to generate a reference clock by receiving a reference clock. Therefore, if the subscriber capacity is insufficient, the self of the DU continues to increase the expansion self in order to expand more capacity. In this case, in the implementation of a small base station, a unit price increase due to GPS mounting occurs for each self of the DU. Increasing the Self Size causes a problem that is difficult to make small.

In addition, since the redundant GPS module supplies the reference clock of 10MHz, 1PPS, TOD, etc., each port by 1 port (GPS A module-> Master A side, GPS B module-> Master B side) to the master board, When it happened, the board on one side of the master was also unable to generate the system clock.

Therefore, the present invention has been proposed to solve the above-mentioned conventional problems, and an object of the present invention is to generate and supply a system clock to the basic self and the extended self when the DU is expanded, and to perform a stable redundancy transfer. The present invention provides a redundant switching device of a base station in a mobile communication system.

In order to achieve the above object, a redundant switching device of a base station in a mobile communication system according to an embodiment of the present invention,

GPS for receiving satellite signals, a master board for receiving and processing signals from the GPS, and a channel card for receiving a signal processed by the master board to perform channel processing, the digital signal in the base station of the mobile communication system A DU basic self for performing processing; A master board daisy-chained with the master board of the DU basic shelf, and a channel card connected with the master board to perform channel processing, and a DU extension shelf for performing digital signal processing at a base station of a mobile communication system. It is made to include the features of the technical configuration.

Hereinafter, an embodiment according to the technical concept of the redundant switching device of the base station in the present invention and mobile communication system as described above with reference to the drawings.

3 is a block diagram of a redundant switching device of a base station in a mobile communication system according to the present invention, FIG. 4 is a block diagram showing a connection between a basic shelf and an extended shelf of a digital unit in FIG. 3, and FIG. Is a detailed block diagram showing the connection of a digital unit of a base station.

As shown in FIG. 4, a GPS 107 for receiving satellite signals, a master board 101 and 102 for receiving and processing signals from the GPS 107, and processing in the master board 101 and 102. A DU basic self (DU # 0) 100 including channel cards 103 to 106 for receiving a received signal and performing channel processing, and performing digital signal processing at a base station of a mobile communication system; A master board connected to the master board of the DU basic shelf 100 by a daisy chain and a channel card 113 to 116 connected to the master boards 111 and 112 to perform channel processing; And a DU extension self (DU # 1) 110 that performs digital signal processing at a base station of a mobile communication system.

As shown in FIG. 3, a master board A 101, a master board B 102, a plurality of channel cards 103 to 106, and a GPS 107 are provided to perform digital signal processing at a base station of a mobile communication system. A DU basic self (DU # 0) 100; Master board A 101 and master board B 112 connected to the master board A 101 and the master board B 102 of the DU basic shelf 100 in a daisy chain, and a plurality of channel cards. DU extended self (DU # 1) 110 having 113 to 116 to perform digital signal processing at a base station of a mobile communication system; It includes a plurality of expansion shelf 120 is configured in the same manner as the DU extension shelf (110).

As shown in FIG. 5, the master board A 101 and the master board B 102 of the DU basic shelf 100 each signal to the DU extended self master board A 111 having a clock active. A port 201 (203) for transmitting the; The clock is configured to include a B port 202 (204) to send a signal to the DU expansion self-master board B 112 operating in standby.

As shown in FIG. 5, the master board A 111 of the DU extension self 110 includes: a control unit 211 for outputting a clock error check / control signal; A 10MHz, 1PPS, TOD signal is input from the A port 201 of the master board A 101 of the DU basic shelf 100 and the A port 203 of the master board B 102 to generate a system clock. First and second system clock generators 212 and 213; First and second PLL controllers 214 that receive the system clocks generated by the first and second system clock generators 212 and 213, respectively, and control the first and second PLLs 218 and 219, respectively. 215; A first PLL 218 for receiving a signal from the A port 201 of the master board A 101 of the DU basic shelf 100 and performing a PLL under the control of the first PLL controller 214; A second PLL (219) for receiving a signal from the A port (203) of the master board B (102) of the DU basic shelf (100) and performing a PLL under the control of the second PLL controller (215); Receives the signals of the first PLL 218 and the second PLL 219 and compares the phases, and transmits the result to the phase comparator 240 in the master board B 112 in the DU extension self 110. A phase comparator 220; First and second signals which receive the signals of the first and second PLLs 218 and 219 and perform voltage controlled oscillation, respectively, and transmit them to the first and second system clock generators 212 and 213, respectively. VCXOs 216 and 217; Under the control of the controller 211, the system clock is input from the first system clock generator 212 and the second system clock generator 213 and multiplexed to be output to the channel cards 113 to 116. Next, the multiplexer 221 is output to the master boards 121 and 122 of the DU extension shelf 120.

As shown in FIG. 5, the master board B 112 of the DU extension self 110 includes: a control unit 231 for outputting a clock error check / control signal; A system clock is generated by receiving 10 MHz, 1PPS, and TOD signals from the B port 202 of the master board A 101 of the DU basic shelf 100 and the B port 204 of the master board B 102, respectively. First and second system clock generators 232 and 233; First and second PLL controllers 234 that receive the system clocks generated by the first and second system clock generators 232 and 233, respectively, and control the first and second PLLs 238 and 239, respectively. 235; A first PLL (238) for receiving a signal from the B port (202) of the master board A (101) of the DU basic shelf (100) and performing a PLL under the control of the first PLL controller (234); A second PLL (239) for receiving a signal from the B port (204) of the master board B (102) of the DU basic shelf (100) and performing a PLL under the control of the second PLL controller (235); Receives the signals of the first PLL 238 and the second PLL 239, and compares the phases by receiving the results of the phase comparator 220 in the master board A 111 in the DU expansion self 110. A phase comparison unit 240; First and second signals which receive the signals of the first and second PLLs 238 and 239 and perform voltage controlled oscillation, respectively, and transmit them to the first and second system clock generators 232 and 233, respectively. VCXOs 236 and 237; Under the control of the controller 231, the system clock is received from the first system clock generator 232 and the second system clock generator 233, multiplexed, and outputted to the channel cards 113 to 116. Next, the multiplexer 241 outputs the master boards 121 and 122 of the DU extension shelf 120.

Here, reference numeral 300 is PDSN, 400 is CAN, 500 is BSC (control station), and 610 to 630 are RFU.

In the mobile communication system according to the present invention configured as described above with reference to the accompanying drawings the operation of the redundant switching device of the base station as follows.

First, the present invention is to facilitate the expansion by separating the DU and RFU for cost reduction and miniaturization of the base station, to generate and supply a system clock to the basic self and the expansion self when the DU is extended and to perform a stable redundancy transfer will be.

Therefore, in the present invention, 1) a part of supplying a reference clock such as 10 MHz, 1PPS, TOD, etc. to the master board through GPS in the basic self of the DU, and 2) generates a system clock again from the master board to provide Chipx16 and Even Sec to the channel card. Part of supplying Chipx8 and Even Sec to the master board of the expansion board in the form of cross redundancy, 3) Synchronizing the clock with 2 PLLs of the system clock coming in the form of cross redundancy from the expansion board, and PLL between the two master boards. It consists of the part of adjusting the phase of the system clock by using, and the part of daisy-chaining the system clock between extended self using the method of 4) and 2) ~ 3).

Referring to the operation of the present invention as follows.

First of all, the present invention has a separation structure of a DU (digital unit) and an RFU (RF unit) in a CDMA2000 1x system, and enables a duplexer generation and duplication operation of a DU when designed to be easily expanded in a small capacity base station.

1) The master boards 101 and 102 duplicated through the GPS 107 in the basic shelf 100 receive one reference clock (10 MHz, 1 PPS, TOD, etc.) by 1 port.

2) The master boards 101 and 102 of the basic shelf 100 generate a system clock through the reference clock and the PLL control.

At this time, Chipx16 (19.6608MHz) and Even Sec are supplied to the channel cards 103 to 106 of the basic shelf 100, and Chipx8 (9.8304MHz), Even Sec, and clock active signals are supplied to the extended shelf 110 and 120. do. The system clock, which is supplied to the expansion self master, is supplied via cable in a cross-duplex manner, and the TOD data is transmitted to the expansion self master through ATM through a hot link interface.

3) The redundant master board of the expansion shelf receives primary and secondary system clocks from the master board A (101) and master board B (102) sides of the basic shelf 100 per board. PLL 218, 219, 238 and 239 and two VCXOs 216, 217 and 236 and 237, respectively, are used to perform PLL control.

In this case, one of the system clocks of the primary and the secondary is selected as the clock active signal received from the basic self 100 to perform PLL control to generate a system clock. PLL control is performed to compare and synchronize the phase with the active system clock.

4) In addition, the master B 112, which is a standby board of the extended shelf 110, performs a PLL control by comparing a phase with a system clock of the active board, thereby receiving a system clock (Chipx8, Even Sec) can be synchronized for all cases. In addition, when a fault occurs in the system clock generated by the master boards 101 and 102 of the basic shelf 100, redundant switching is performed to stably supply the system clock.

5) The system clock generated by the master boards 111 and 112 of the expansion shelf 110 is supplied to the next expansion shelf 120 again.

6) Repeat the above 2) ~ 5) to daisy-chain the DU of the DU to be extended with the reference clock generated by one GPS 107 mounted on the basic shelf 100 to daisy chain the system clock. By creating it, it is possible to easily secure expandability.

As described above, the present invention generates and supplies a system clock to the basic self and the extended self when the DU is extended, and stably performs the redundant switching.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, the redundant switching device of the base station in the mobile communication system according to the present invention is to facilitate the expansion by separating the DU and RFU in order to reduce the cost and miniaturization of the base station, the base self and the expansion self when expanding the DU The system clock is generated and supplied to the system, and redundancy switching can be stably performed.

Therefore, if the subscriber capacity is insufficient in the small base station, the DU's self will be daisy chained to the extended self using the system clock provided by the base self to continuously increase the extended self to expand the capacity, thereby resetting the synchronizer clock. The cost savings can be achieved by eliminating the GPS mounted on the extended shelf, and the advantage is that the system can be made smaller by reducing the size of the shelf.

In addition, in the conventional redundant switching method of clock duplication, the reference clock is supplied to the master board one port, so when one reference clock fails, the board on one side of the master board does not generate the system clock. In addition, by connecting the reference clock to the master board in the form of cross redundancy and extending the PLL of each master board from one to two to perform PLL control, synchronization can be continued in one board. Synchronization can be continuously synchronized with the system clock of the master board operating with clock active, so that all four reference clocks can be synchronized. Therefore, the present invention implements a true system clock redundancy technique. .

Claims (5)

GPS for receiving satellite signals, a master board for receiving and processing signals from the GPS, and a channel card for receiving a signal processed by the master board to perform channel processing, the digital signal in the base station of the mobile communication system A DU basic self for performing processing; A master board daisy-chained with the master board of the DU basic shelf, and a channel card connected with the master board to perform channel processing, and a DU extension shelf for performing digital signal processing at a base station of a mobile communication system. Redundancy switching device of the base station in the mobile communication system, characterized in that configured to include. A DU basic self having a master board A, a master board B, a plurality of channel cards, and a GPS to perform digital signal processing at a base station of a mobile communication system; A master board A and a master board B daisy-chained with the master board A and the master board B of the DU basic shelf, and a plurality of channel cards to perform a digital signal processing at a base station of a mobile communication system; ; The redundant switching device of the base station in the mobile communication system, characterized in that it comprises a plurality of extended self is configured in the same manner as the DU extended self. The method of claim 2, wherein the master board A and master board B of the DU basic self, respectively, A port for transmitting a signal to a DU expansion self master board A whose clock is active;  The apparatus of claim 1, wherein the clock is configured to include a B port for transmitting a signal to the DU expansion self master board B operating in standby mode. The method of claim 2, wherein the master board A of the DU extension self, A controller for outputting a clock error check / control signal; First and second system clock generators for generating a system clock by receiving 10 MHz, 1PPS, and TOD signals from the A port of the master board A and the A port of the master board B of the DU basic self; First and second PLL controllers respectively receiving system clocks generated by the first and second system clock generators and controlling first and second PLLs, respectively; A first PLL receiving a signal from the A port of the master board A of the DU basic self and performing a PLL under control of the first PLL controller; A second PLL receiving a signal from the A port of the master board B of the DU basic self and performing a PLL under the control of the second PLL controller; A phase comparator configured to receive signals from the first PLL and the second PLL, compare phases, and transmit a result to a phase comparator in a master board B in the DU extension self; First and second VCXOs which receive the signals of the first and second PLLs and perform voltage controlled oscillations, respectively, and transmit them to the first and second system clock generators; Under the control of the controller, the system clock from the first system clock generator and the second system clock generator receives a multiplexed output to the channel card, and a multiplexing unit for outputting to the master board of the next DU expansion self; Redundancy switching device of the base station in the mobile communication system, characterized in that configured. The master board B of any one of claims 2 to 4, wherein A controller for outputting a clock error check / control signal; First and second system clock generators for generating a system clock by receiving 10 MHz, 1 PPS, and TOD signals from the B port of the master board A and the B port of the master board B of the DU basic self; First and second PLL controllers respectively receiving system clocks generated by the first and second system clock generators and controlling first and second PLLs, respectively; A first PLL receiving a signal from a B port of the master board A of the DU basic self and performing a PLL under control of the first PLL controller; A second PLL receiving a signal from the B port of the master board B of the DU basic self and performing a PLL under control of the second PLL controller; A phase comparator configured to receive signals of the first PLL and the second PLL, and to compare phases by receiving a result of a phase comparator in master board A in the DU extension self; First and second VCXOs which receive the signals of the first and second PLLs and perform voltage controlled oscillations, respectively, and transmit them to the first and second system clock generators; Under the control of the controller, the system clock from the first system clock generator and the second system clock generator receives a multiplexed output to the channel card, and a multiplexing unit for outputting to the master board of the next DU expansion self; Redundancy switching device of the base station in the mobile communication system, characterized in that configured.

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