CN1719756B - Method for implementing mobile communication digital optical fibre repeater system - Google Patents
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Abstract
This invention discloses a direct sending system for mobile communication digital fibers and a realization method including a near end relay part and a remote part. Both of them include the subsystems of a RF T-R, upper and lower conversion, ADC/DAC and a base band process, a fiber T/R device, a monitor subsystem and a power supply, among which, the near end relay set converts the received base station downward signals to base band I/Q signals or lower IF signals to be converted to digital signals via ADC to be bundled to serial data in a frame form to be sent to a remote processor via a fiber T/R unit to be de-framed by a base-band process unit to recover the I/Q or low IF signals to be converted to analog signals via DAC transformation then to be converted to RF signals and emitted by an emit subsystem. The remote processor sends the received mobile up-line signals to the receiving end of the base station via the above inverse process.
Description
Technical Field
The invention relates to a mobile communication system, in particular to a method for realizing a multi-carrier wireless signal remote coverage system adopting a digital optical fiber transmission mode.
Background
With the rapid development of mobile communication business in China, the importance of wireless network optimization and network coverage is shown increasingly. The repeater system has the characteristics of low investment cost and capability of rapidly expanding a coverage area, and is an indispensable part in wireless network optimization and coverage. The repeater system is divided into an outdoor repeater and an indoor repeater. The former mainly comprises: wireless repeater, optical fiber repeater, multi-band frequency shift repeater, etc.; the latter is also called indoor distribution system, and mainly includes radio frequency transmission mode, optical fiber transmission mode, and electro-optical hybrid transmission mode.
However, the wireless signal long-distance transmission system of the repeater generally adopts an analog transmission technology. Among them, the analog optical fiber transmission system is one in which a relatively large number are employed. The dynamic range of long-distance transmission and subarea transmission is reduced due to the defect of inherent noise superposition in the analog optical fiber transmission mode, and the problems of long-distance transmission of multi-carrier signals and signal coverage with large capacity and large dynamic range are difficult to solve.
Disclosure of Invention
In order to solve the technical problems of the traditional repeater signal transmission mode, the invention discloses a method for realizing a mobile communication digital optical fiber repeater system. The method adopts a digital optical fiber mode to realize the remote transmission of multi-carrier mobile communication signals and the signal coverage with large capacity and large dynamic range, and adds a flexible novel means for the remote coverage of radio frequency signals with large dynamic range and large capacity for a mobile communication system.
The mobile communication digital optical fiber repeater system adopts The CPRI (Common Public Radio Interface, established by CPRI organization) Interface standard. CPRI defines an interface relationship between a base station data processing control unit rec (radio Equipment control) and a base station transceiver unit re (radio Equipment), and a data structure thereof is directly used for remote data transmission of a radio frequency signal of a repeater.
The technical scheme of the invention is as follows:
the system is composed of a near-end repeater 101 and a far-end machine 102, wherein the near-end repeater and the far-end machine change received signals into I/Q baseband or low intermediate frequency signals, then the signals are processed by A/D and data signals to form digital signals, and transmission between the signals is carried out by adopting optical fiber transmission through a digital optical fiber transceiver, and typical applications of the system are as follows: the transmission is carried out by using an optical cable specified by an Ethernet protocol. The downlink signal transmitted from the mobile communication base station system such as GSM, CDMA, WCDMA, CDMA2000, etc. is converted into baseband signal or low-intermediate frequency signal by the down converter 207 in the base station near-end repeater system 101 provided by the system, converted into digital signal by the A/D converter 211, packed into frame format suitable for CPRI interface requirement by the baseband processing unit 213, and transmitted to the far-end machine by the digital optical fiber transceiver 214 and the optical fiber 215; the remote end machine sends the baseband digital signal to the baseband processing unit 217 through the digital optical fiber transceiver 216, restores the baseband digital signal into baseband data, changes the baseband data into a baseband signal through the D/A converter 218, converts the baseband data into a radio frequency signal through the up converter 221, and then transmits the radio frequency signal to a coverage area through the radio frequency transmitter and the antenna 230 to achieve the purpose of remote coverage; the signal from the mobile terminal is received by the remote terminal 102 and then transmitted back to the mobile communication base station by the reverse process of the above process; the system also comprises a monitoring system and a power supply system; the remote machine provided by the system can become a remote subsystem of different mobile communication base stations.
The frequency range of the downlink signal transmitted by the base station may be: 869-894 MHz of CDMA IS-95 system, 930-960 MHz of GSM system, 1805-1880 MHz of GSM1800 system, 1930-1990 MHz of CDMA2000 system, 2110-2170 MHz of WCDMA system; the frequency range of the uplink signal received by the remote terminal may be: 824-849 MHz of a CDMA IS-95 system, 885-915 MHz of a GSM system, 1710-1785 MHz of a GSM1800 system, 1850-1910 MHz of a CDMA2000 system and 1920-1970 MHz of a WCDMA system.
The transmission between the near-end repeater and the far-end unit is completed by a digital optical fiber transceiver; one of typical data transmission formats is a frame format using a CPRI interface standard; the serial data rates on the digital fiber transceivers of the near-end repeater and the far-end unit and the uplink and downlink optical fiber links can be as follows: 614.8Mbps, 1228.8Mbps, 2457.6Mbps, selected by different practical applications.
The baseband signals of the up-conversion and down-conversion of the near-end repeater 101 and the far-end unit 102 are both I/Q quadrature baseband or low intermediate frequency signals, wherein the digital I/Q signals obtained through a/D conversion can be used for I/Q amplitude and phase adjustment of a radio frequency predistortion power amplifier transmission link.
The up-converters 209, 221 and down-converters 207, 222, 223 may take the form of analog direct I/Q up-converters, direct I/Q down-converters, intermediate frequency I/Q up-converters, intermediate frequency I/Q down-converters, digital intermediate frequency I/Q up-converters, and digital intermediate frequency I/Q down-converters.
The signal of the I/Q baseband can adopt a narrow band form or a broadband form, wherein the typical application is that the bandwidth of the narrow band signal is 300KHz and 1.25MHz, and the bandwidth of the broadband signal is 5MHz, 10MHz and 15 MHz.
For network management parameters of a repeater system, a serial data interface of HDLC is adopted for transmission between a near-end repeater and a far-end machine, a data chain of a signal and a data chain of a network manager are combined together in the repeater to form a specific frame format for transmission, wherein the typical application is that the frame format suitable for a CPRI interface protocol is formed and sent to an 8B/10B codec.
The baseband processing unit comprises a base station relay end baseband processing module, a far-end baseband processing module or a low-intermediate frequency baseband processing module. In the relay end baseband processing module, the downlink signal of the base station is adjusted to be suitable for the A/D amplitude and frequency range through a group of gain and response bandwidth variable operational amplifier group 301, then sent to the A/D converter group 302, changed into digital signal through 12bit/s A/D (the bit number can be changed into 10bit, 14bit and 16bit according to different systems), sent to the baseband processing unit 303, the data chain of the signal and the data chain of the network management are combined together to form a specific frame format, then sent to the encoder 304, the 8B/10B encoder 304 carries out the error detection, the DC removal and the encoding of the data signal sent from the baseband processing unit 303, then sent to the optical fiber transceiver after the error detection, the DC removal and the encoding of the data signal, sent to the far-end machine 102 through the optical fiber, and the uplink high-speed serial digital signal from the far-end machine 102 is received through the optical fiber transceiver 308 and sent to the 8B/10B decoder 309 for error detection and data frame format recovery Then the data is sent to a baseband processing unit 310 in parallel to restore into I/Q data and network management HDLC interface data, wherein the I/Q data is sent to a 12-bit (the bit number can be respectively changed into 10bit, 14bit and 16bit according to different systems) D/A converter group 311 to change the I/Q data into an analog signal, and then the analog signal is filtered by a filter 312 which has variable gain and bandwidth and consists of an operational amplifier and then is sent out; in the far-end baseband processing module, after down-converting the uplink signal from the mobile terminal, the signal is adjusted to be suitable for the amplitude and frequency range of A/D through a group of operational amplifier groups 317 with variable gain and response bandwidth, the signal is sent into 12bit/s (the bit number of the signal can be respectively changed into 10bit, 14bit and 16bit according to different systems) A/D converter groups 318 to be changed into a digital signal, the signal input by A/D and the interface input signal of network management HDLC are formed through a baseband processing unit 319 to form an interface frame format suitable for the CPRI protocol, the interface frame format is sent into an 8B/10B encoder 320 to carry out error detection, DC removal and encoding of 8B/10B, the data is sent to an optical fiber transceiver in series, and the data is sent to the far-end machine 102; the downlink high-speed serial digital signal from the relay terminal 101 is received by the optical fiber transceiver 324 and sent to the 8B/10B decoder 325 for error detection and data frame format recovery, and is sent to the baseband processing unit 326 in parallel, and the data is recovered to I/Q data and HDLC interface data of the network management, wherein the I/Q data is sent to the 12bits (the bit number can be changed into 10bits, 14bits and 16bits respectively according to different systems) D/A converter group 327 to be changed into an analog signal, and then is filtered by the filter 328 which has variable gain and bandwidth and consists of an operational amplifier and then is sent out; in the middle and low frequency baseband processing module, the signal input to the A/D converter 338 is a low and medium frequency signal, and becomes a digital signal through 12bit/s A/D, the bit number of the A/D converter can be changed into 10bit, 14bit, 16bit according to different systems, the baseband processing unit 335 forms the signal and the signal input by the HDLC interface 336 of the network management to form an interface frame format suitable for CPRI protocol, and sends the signal into the 8B/10B encoder, and sends the signal into the optical fiber transceiver 339 after error detection, DC removal and encoding, and sends the data to the optical fiber in series; the remote up-converter 221, down-converters 222, 223, transmitter 224 and receivers 225, 226 may be configured in 2 forms, one of which is an intermediate frequency I/Q up-down conversion form, and the other of which is a direct up-down conversion form, wherein the up-converters 445, 446, 447 are directly up-converted from baseband or low intermediate frequency signals, and the down-converters 454, 455, 456 are directly converting radio frequency signals to baseband or low intermediate frequency signals. Different application combinations can be selected according to different application backgrounds, wherein the I/Q signals are low intermediate frequency signals or baseband signals, the up-conversion is carried out by two times of frequency conversion, and the intermediate frequency can be selected according to different application systems; the down-conversion is also subjected to frequency conversion twice; among them, the WCDMA system is one of typical applications, and can also be used for CDMA2000, CDMA, and GSM systems.
The up-conversion circuit of the remote terminal consists of a low-pass filter 501, a high-pass filter 503, an up-conversion circuit 505, an orthogonal power divider 506 and a combiner 508; the down converter circuit consists of a splitter 509, a radio frequency amplifier with AGC 510, a down converter circuit 511, a quadrature power splitter 515, a high pass filter 512, a baseband or low intermediate frequency amplifier with AGC 513 and a low pass filter.
The monitoring system circuits 210 and 227 of the present invention may be composed of different circuit modules, wherein, the monitoring data obtained by the monitoring board is HDLC data stream formed by the HDLC interface 702 and sent to the baseband processing unit 701, and the control data sent by the baseband processing unit 701 is sent to the monitoring information obtaining and processing unit 704 through the HDLC interface 702 and then distributed to the relevant monitoring board through the data bus 705.
The method provided by the invention adopts comprehensive technology, and mainly comprises the following steps: various standard protocols and interface technologies, data coding and decoding technologies, high-speed data processing technologies, high-speed analog-to-digital conversion technologies, high-precision modulation-demodulation frequency conversion technologies, low-noise technologies, high-power linear technologies, high-stability frequency source technologies and the like.
By comprehensively adopting the various technologies, the system has the following remarkable advantages and effects: the defects of adopting an analog transmission technology (such as an analog optical fiber transmission technology) in the traditional repeater wireless signal long-distance transmission are fundamentally avoided; the long-distance transmission of wireless signals of the multi-carrier high-capacity repeater is facilitated; the system performance is stable and reliable; the large-scale batch production of products is facilitated; within the range of 0-30 Km, high signal-to-noise ratio digital transmission of three sectors and multiple carriers can be realized; the system is provided with a gigabit Ethernet standard interface, a low-noise receiver, a high-power transmitter and a high-stability frequency source; the ultra-wideband I/Q up-down frequency conversion function and the high-speed large dynamic A/D, D/A conversion function are realized; the remote and short-range repeater has the functions of parameter setting, state query, fault uploading and alarming; and is provided with an HDLC backup interface. The method can be widely applied to single-pair optical fiber transmission and coverage of three sectors or multiple sectors, single-pair optical fiber transmission and coverage of single carrier and multiple sectors, and single-pair optical fiber transmission and coverage of multiple sectors and multiple carriers. The invention is suitable for the long-distance transmission of multi-carrier mobile communication signals, realizes large capacity and large dynamic coverage, and adds a novel base station remote system for a mobile communication system.
The invention has been described in a descriptive manner throughout, and the terminology used therein is intended to be in the nature of description rather than of limitation. Many further modifications and variations of the present invention are possible in light of the above teachings or may be acquired from practice of the invention. Therefore, within the scope of the appended claims, the invention may take a variety of different implementations from the specifically described embodiments.
Brief description of the drawingsthe following is a brief description of the patent to the invention:
FIG. 1 is a block diagram of a system of the present invention;
FIG. 2 is a system composition diagram illustrating the logical connections of the system and the system operation;
FIG. 3 depicts the logical connections and operation of the baseband processing modules of the system;
FIG. 4 depicts the logical connections and operation of the modem and up/down converter of the remote unit;
FIG. 5 depicts the components and operation of the up-down converter of the system;
FIG. 6 depicts the component circuits of the frequency source of the system and its typical parameter settings;
FIG. 7 illustrates the block diagram and operation of the remote and proximity monitoring systems of the present invention.
In the above drawings, the reference numerals are explained as follows:
101: a relay terminal; 102: a remote machine; 103. 215: an optical fiber; 104. 201: a coupler; 202. 229: a duplexer; 203: an RF module; 232: a base station main antenna; 207. 454, 455, 456: a down converter; 211. 302, 318, 338: an A/D converter; 213. 217, 303, 310, 319, 326, 335, 701: a baseband processing unit; 214. 216: an optical transceiver; 218. 311, 327, 338: a D/A converter; 221. 445, 446, 447: an up-converter; 224; an antenna: 230: a transmitter; 301. 312, 328: an operational amplifier filter; 314. 336, 702: an HDLC interface; 304. 309, 320, 325, 323, 333: a codec; 305. 308, 321, 324, 339: a fiber optic transceiver; 317: an operational amplifier; 307. 322: an uplink optical fiber link; 306. 323: a downlink optical fiber link; 501. 514: a low-pass filter; 503. 512: a high-pass filter; 505: an up-conversion circuit; 506. 515: an orthogonal power divider; 508: a combiner; 509: a splitter; 510: a radio frequency amplifier; 511: a down-conversion circuit; 513: a low intermediate frequency amplifier; 705: a data line; 704: and the monitoring information acquisition and processing unit.
Detailed Description
Preferred embodiments corresponding to the present invention will be described in detail below with reference to the accompanying drawings:
1. FIG. 1 is a schematic diagram illustrating the overall architecture of a digital fiber optic repeater system. In the figure, a near-end repeater 101 finishes acquisition and transmission of base station signals through a coupler 104, a far-end machine 102 finishes acquisition and transmission of mobile terminal signals through an antenna feeder, and a fiber transceiver of an ethernet standard is adopted between the near-end repeater and the far-end machine to realize digital signal transmission through an optical fiber 103.
2. FIG. 2 is a schematic diagram illustrating the system components of a digital fiber optic repeater system. Fig. 2a shows a near-end relay subsystem, and fig. 2b shows a far-end relay subsystem. The near-end repeater feeds a mobile communication downlink signal from a base station main antenna 232 into a duplexer 202 through a coupler 201, the mobile communication downlink signal is down-converted to a baseband I/Q or low-intermediate frequency signal through an RF module 203 by a down-converter 207, then the baseband I/Q or low-intermediate frequency signal is converted into a digital signal through an A/D converter 211, the digital signal is packaged into serial data according to a certain frame format by a baseband processing unit 213, and the serial data is transmitted to a far-end machine through an optical fiber 215 by an optical transceiver 214. At the remote end, after being deframed by the optical transceiver 216 and the baseband processing unit 217, the signals are restored to I/Q or low-intermediate frequency signals by the D/a converter 218, up-converted to radio frequency by the up-converter 221, and finally transmitted to the coverage area by the transmitter 224, the duplexer 229 and the antenna 230. The uplink signal from the mobile terminal passes through the remote terminal, and the downlink reverse process of the remote terminal is used for returning the uplink serial data signal to the near-end repeater through the optical fiber 215, and then the uplink radio frequency signal is fed to the base station through the downlink reverse process of the near-end repeater. Thus, the remote coverage function of the mobile communication base station is completed, and a remote end of the base station is formed.
3. Fig. 3a is a logical connection diagram of the baseband processing module of the near-end repeater of the present invention. The figure also describes the following working process of the baseband processing module of the near-end repeater:
the 6 paths of I/Q input signals are converted into parallel digital signals by an A/D converter group 302 of 12bit/s (or respectively changed into 10bit, 14bit and 16bit according to different systems) through a relay end operational amplifier filter 301 with variable gain and bandwidth, the signals and input signals from a network management HDLC interface 314 form data signals conforming to a CPRI protocol frame structure through a baseband processing unit 303, then the data signals are subjected to error detection, direct current removal and coding through an 8B/10B codec 304 to form high-speed serial digital signals, and finally the high-speed serial digital signals are transmitted to a far-end machine through a downlink optical fiber link through an optical fiber transceiver 305;
the uplink high-speed serial digital signal from the remote machine is received by the optical fiber transceiver 308, and after the error detection and decoding are carried out by the 8B/10B codec 309, the frame is decoded by the baseband processing unit 310, and the signals are respectively restored into an I/Q data signal and a network management HDLC interface data signal, wherein the I/Q signal is converted into an analog signal by the D/A converter group 311 of 12bits (or 10bits, 14bits, 16bits), and finally the signal sends out an I/Q output signal by the operational amplifier filter 312 with variable gain and bandwidth.
The rates of the serial digital signals of the uplink and downlink optical fiber transceivers and the optical fiber links in the relay end baseband processing module can be respectively designed as follows according to the actual application requirements: 614.8Mbps, 1228.8Mbps, 2457.6 Mbps.
4. Fig. 3b is a diagram of the logical connections of the baseband processing modules of the remote unit of the present invention. The figure also describes the following working process of the far-end machine baseband processing module:
after down-conversion, the uplink signal from the mobile terminal is adjusted to be suitable for the amplitude and frequency range of A/D through a group of gain and response bandwidth variable operational amplifier group 317, then the signal is converted into a digital signal of 12bit/s (or 10bit, 14bit, 16bit) through an A/D converter group 318, the signal and the input signal from a network management HDLC interface form a data signal suitable for a CPRI protocol frame structure through a baseband processing unit 319, then the signal is subjected to error detection, DC removal and coding through an 8B/10B codec 320 to form a high-speed serial digital signal, and finally the high-speed serial digital signal is transmitted to a near-end relay through an uplink optical fiber link 322 through an optical fiber transceiver 321;
the downlink high-speed serial digital signal from the relay terminal is received by the optical fiber transceiver 324, and after the error detection and decoding are carried out by the 8B/10B codec 325, the frame is decoded by the baseband processing unit 326, and the I/Q signal and the network management HDLC interface data signal are respectively restored, wherein the I/Q signal is converted into an analog signal by the D/A converter group 327 of 12bits (or 10bits, 14bits, 16bits), and finally the signal sends out an I/Q output signal by the operational amplifier filter 328 with variable gain and bandwidth.
The speed of the serial digital signals of the uplink and downlink optical fiber transceivers and the optical fiber links in the remote-end machine baseband processing module can be respectively designed as follows according to the actual application requirements: 614.8Mbps, 1228.8Mbps, 2457.6 Mbps.
5. Fig. 3c is a logic connection diagram of the low if baseband processing module according to the present invention. The figure also describes the following working process of the low intermediate frequency baseband processing module:
the low-intermediate frequency signal from the down converter is converted into a digital signal by an A/D converter group 338 of 12bit/s (or 10bit, 14bit, 16bit), the signal and an input signal from a network management HDLC interface 336 form a data signal suitable for a CPRI protocol frame structure by a baseband processing unit 335, then an 8B/10B codec 333 performs error detection, DC removal and coding to form a high-speed serial digital signal, and finally the high-speed serial digital signal is sent into an optical fiber link by an optical fiber transceiver 339;
the high-speed serial digital signal from the optical fiber link is received by the optical fiber transceiver 339, subjected to error detection and decoding by the 8B/10B codec 323, deframed by the baseband processing unit 335, and respectively restored to an I/Q data signal and a network management HDLC interface data signal, wherein the I/Q signal is converted into a medium-low frequency analog signal by the D/A converter group 338 of 12bits (or 10bits, 14bits, 16bits) and then sent to the up-converter.
The rates of the serial digital signals of the uplink and downlink optical fiber transceivers and the optical fiber links in the medium and low frequency baseband processing module can be respectively designed as follows according to the actual application requirements: 614.8Mbps, 1228.8Mbps, 2457.6 Mbps.
6. Fig. 4a, 4b, 5a and 5b are diagrams illustrating logical connections of the modem and the up/down converter provided by the present invention, using three sectors/three carriers as an example. Wherein, fig. 4a is an intermediate frequency I/Q up-down conversion form; fig. 4b is a direct up-down conversion format. The frequency bands identified in fig. 4a are exemplified by a WCDMA system, but the invention is equally applicable to CDMA2000, CDMA and GSM systems.
The I/Q signals in the figure are low intermediate frequency signals or baseband signals. The up-conversion is performed by two intermediate frequencies, and the selection of the intermediate frequency can be different according to different application systems. Wherein, fig. 4a can also adopt other combination modes according to the application context; the up-converters 445, 446, 447 in fig. 4b are up-converted from baseband signals or low intermediate frequency signals directly to radio frequency signals, and the down-converters 454, 455, 456 are down-converters for converting radio frequency signals directly to baseband signals or low intermediate frequency signals, which are three groups in total, one of which is shown in fig. 4 b. The up-conversion circuit shown in fig. 5a is composed of a low-pass filter 501, a high-pass filter 503, an up-conversion circuit 505, a quadrature power divider 506 and a combiner 508; the down converter circuit shown in fig. 5b consists of a splitter 509, a radio frequency amplifier with AGC 510, a down converter circuit 511, a quadrature power divider 515, a high pass filter 512, a baseband or low intermediate frequency amplifier with AGC 513 and a low pass filter 514.
The I/Q modulation circuit is mainly used for up-conversion of a base station relay end and a remote machine covering end. The use of I/Q up-conversion to separate out the carriers provides benefits in the RF power efficiency of the system, while also being simple and practical to implement. In order to eliminate the dc drift of data and remove the folding effect of up-down frequency conversion caused by asynchronous frequency near dc, a high pass is needed before modulation.
The I/Q demodulation circuit is mainly used for down-conversion of a base station repeater end and a remote end covering end. In order to eliminate the dc drift of data and remove the folding effect of up-down frequency conversion caused by asynchronous frequency near dc, a high pass is needed after demodulation. Meanwhile, in order to control the dynamic range of the ADC inlet, the demodulator needs to have an AGC function, and in order to prevent the influence of the noise on the adjacent channel, a low pass filter is also needed in the demodulator.
7. Fig. 6a, 6b and 6c show an example of a typical frequency source circuit provided by the present invention. The frequency source has different working modes, and the design requirements for the frequency source circuit are necessarily different. Fig. 6c shows a carrier tracking circuit of the frequency source circuit, which is used to implement carrier tracking at the relay end and the remote coverage end of the base station.
For three carriers, the frequency source provides three frequencies selected from 190MHz, 380MHz and 2300MHz + n × 0.2MHz (n is 0-300), and each frequency needs to output two sets.
For a single carrier tri-sector, the frequency source provides a frequency selected from 190MHz, 380MHz and 2300MHz + nx0.2 MHz (n ═ 0-300), and 6 sets are output.
For a three-carrier three-sector, the frequency source provides the same frequency as in the first case.
8. FIG. 7 is a circuit block diagram of a repeater monitoring system provided in the present invention. The monitoring system implements real-time monitoring of the up-down converter, the I/Q converter, the receiving circuit, the transmitting circuit, the antenna interface and the like. The monitoring items comprise: physical interface parameters for data transmission; baseband processor parameters; parameters of an I/Q up-down converter; a frequency source parameter; receiving link parameters; transmitting the link parameters; power amplifier parameters; antenna parameters, HDLC interface parameters, etc.
In the figure, the monitoring data provided by each monitoring board is transmitted to the baseband processing unit 701 after passing through the data bus 705, the HDLC interface 702 forms an HDLC data stream through the monitoring information obtaining and processing unit 704; the control data sent from the baseband processing unit 701 is decomposed by the HDLC interface 702, and then distributed to the relevant monitoring boards via the data bus 705 via the monitoring information acquisition and processing unit 704.
Claims (13)
1. A method for implementing a mobile communication digital optical fiber repeater system comprises a near-end repeater (101) and a far-end unit (102), and is characterized in that: the near-end repeater and the far-end machine change the received signals into I/Q baseband or low-intermediate frequency signals, then the signals are processed by A/D and data signals to form digital signals, and the transmission between the signals is carried out by adopting an optical cable specified by an Ethernet protocol through a digital optical fiber transceiver; the method specifically comprises the following steps: the downlink signal transmitted from the GSM, CDMA, WCDMA or CDMA2000 mobile communication base station system is converted into baseband signal or low-intermediate frequency signal by the down converter (207) in the near-end repeater (101), and converted into digital signal by the A/D converter (211), the digital signal is packed into frame format suitable for CPRI interface requirement by the baseband processing unit (213) of the near-end repeater to become baseband digital signal, and the packed baseband digital signal is transmitted to the far-end machine by the digital fiber transceiver (214) and the optical fiber (215); the remote machine sends the baseband digital signal into a baseband processing unit (217) of the remote machine through a digital optical fiber transceiver (216), restores the baseband digital signal into baseband data, changes the baseband data into a baseband signal through a D/A converter (218), converts the baseband signal into a radio frequency signal through an up-converter (221), and transmits the radio frequency signal to a coverage area through a radio frequency transmitter and an antenna (230) to achieve the purpose of remote coverage; after the signal from the mobile terminal is received by the far-end machine (102), the signal is transmitted back to the mobile communication base station by the reverse process of the process from the mobile communication base band to the far-end machine through the near-end repeater; the mobile communication digital optical fiber repeater system also comprises a monitoring system and a power supply system;
the frequency range of the downlink signal transmitted by the base station is one of the following: 869-894 MHz of CDMA IS-95 system, 930-960 MHz of GSM system, 1805-1880 MHz of GSM1800 system, 1930-1990 MHz of CDMA2000 system, 2110-2170 MHz of WCDMA system; the frequency range of the uplink signal received by the remote terminal is one of the following: 824-849 MHz of a CDMA IS-95 system, 885-915 MHz of a GSM system, 1710-1785 MHz of a GSM1800 system, 1850-1910 MHz of a CDMA2000 system and 1920-1970 MHz of a WCDMA system;
the transmission between the near-end repeater and the far-end unit is completed by a digital optical fiber transceiver, and one of data transmission formats is a frame format of a CPRI interface standard; the serial data rates of the digital optical fiber transceivers of the near-end repeater and the far-end machine and the uplink and downlink optical fiber links are one of the following rates: 614.8Mbps, 1228.8Mbps, 2457.6 Mbps;
in a relay end baseband processing module, a downlink signal of a base station is adjusted to be suitable for an A/D amplitude and frequency range through a group of operation amplifier groups (301) with variable gain and response bandwidth, then the downlink signal is sent to an A/D converter group (302), after the downlink signal is changed into a digital signal through A/D, a data chain of the digital signal and a data chain of a network management are combined together to form a specific frame format, and then the digital signal is sent to an encoder (304), wherein the bit number of the A/D converter group is one of 10bit, 12bit, 14bit and 16 bit.
2. The method of claim 1, wherein the baseband signals of the up-conversion and down-conversion of the near-end repeater (101) and the far-end repeater (102) are both I/Q baseband or low-if signals, and wherein the digital I/Q signals obtained through the a/D conversion are used for I/Q amplitude and phase adjustment of the transmission link of the rf predistortion power amplifier.
3. The method for implementing a mobile communication digital fiber optic repeater system according to claim 1, wherein the up-converters (208), (209), (221) are analog direct I/Q up-converters or intermediate frequency I/Q up-converters;
or,
the down converters (207), (222) and (223) adopt analog direct I/Q down converters or intermediate frequency I/Q down converters.
4. The method of claim 1, wherein the I/Q baseband signal is in a narrow band with a bandwidth of 300KHz or 1.25 MHz; or a broadband signal with the bandwidth of 5MHz, 10MHz or 15MHz is adopted.
5. The method of claim 1, wherein the network management parameter transmission between the near end repeater and the far end repeater is a serial data interface of HDLC, and in the repeater, the data chain of the signal and the data chain of the network manager are combined together to form a frame format suitable for CPRI interface protocol and then sent to 8B/10B codec.
The method of claim 1, wherein each baseband processing unit comprises a base station relay end baseband processing module, a remote end baseband processing module, or a low-if baseband processing module.
7. The method of claim 6, wherein in the intermediate baseband processing module, the 8B/10B encoder (304) performs error detection, DC removal and encoding on the received data signal with 8B/10B, and sends the data signal to the fiber transceiver, and then to the remote end (102) via the fiber, and the uplink high-speed serial digital signal from the remote end (102) is received by the fiber transceiver (308) and sent to the 8B/10B decoder (309) for error detection and data frame format recovery, and then further recovered to I/Q data and network management HDLC interface data, wherein the I/Q data is sent to the D/A converter group (311) to be converted into analog signal, and then filtered by the filter (312) with variable gain and bandwidth and composed of operational amplifier, the D/A converter group has one of 10bit, 12bit, 14bit and 16 bit.
8. The method of claim 6 wherein the repeater system, in a far-end baseband processing module, an uplink signal from a mobile terminal is subjected to down-conversion, then is adjusted to be suitable for the amplitude and frequency range of A/D through a group of operational amplifier groups (317) with variable gain and response bandwidth, is sent to an A/D converter group (318) to be changed into a digital signal, an A/D input signal and an interface input signal of a network management HDLC are formed into an interface frame format suitable for a CPRI protocol, is sent to an 8B/10B encoder (320) to carry out error detection, DC removal and encoding on 8B/10B, is sent to an optical fiber transceiver and then is serially sent to an optical fiber to be transmitted to a far-end machine (102), the number of bits of the A/D converter group is one of 10bits, 12bits, 14bits and 16 bits.
9. The method for implementing a mobile communication digital fiber repeater system according to claim 6, wherein in the far-end baseband processing module, the downlink high-speed serial digital signal from the near-end repeater (101) is received by the fiber transceiver (324), sent to the 8B/10B decoder (325) for error detection and data frame format recovery, and then further recovered to I/Q data and HDLC interface data of the network manager, wherein the I/Q data is sent to the D/A converter group (327) to be converted into analog signals, and then filtered by the filter (328) composed of an operational amplifier with variable gain and bandwidth, and the D/A converter group has one of 10bit, 12bit, 14bit and 16 bit.
10. The method for implementing a mobile communication digital fiber repeater system according to claim 6, wherein in the middle and low frequency baseband processing module, the signal input to the A/D converter (338) is a low and medium frequency signal, the A/D signal is converted into a digital signal, the number of bits of the A/D converter is one of 10bit, 12bit, 14bit and 16bit, the low and medium frequency signal and the signal input from the HDLC interface (336) of the network manager form an interface frame format suitable for the CPRI protocol, and the interface frame format is sent to the 8B/10B encoder, and the signal is sent to the fiber transceiver (339) after error detection, DC removal and encoding, and then is sent to the fiber in series.
11. A method for implementing a mobile communication digital fiber optic repeater system according to claim 1, wherein the up-converter (221), down-converters (222), (223), transmitter (224) and receivers (225), (226) are formed in 2 forms in the remote end, one is an intermediate frequency I/Q up-down conversion form, and the other is a direct up/down conversion form.
12. The method of claim 11 wherein the up/down converter of the remote unit performs two frequency conversions on the signal.
13. The method of claim 11, wherein the up-converter circuit of the up-converter and down-converter of the remote unit comprises a low-pass filter (501), a high-pass filter (503), an up-converter circuit (505), a quadrature power divider (506) and a combiner (508); the down converter circuit comprises a splitter (509), a radio frequency amplifier (510) with AGC, a down conversion circuit (511), a quadrature power divider (515), a high pass filter (512), a baseband or low intermediate frequency amplifier (513) with AGC and a low pass filter.
14. The method for implementing a mobile communication digital fiber repeater system according to claim 1, wherein in the monitoring system circuit (210), (227), the monitoring data obtained by the monitoring board is sent to the baseband processing unit (701) by the HDLC interface (702) to form HDLC data stream; the control data sent by the baseband processing unit (701) is sent to the monitoring information acquisition and processing unit (704) through the HDLC interface (702), and then is distributed to the relevant monitoring boards through the data bus (705).
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| CN101282275B (en) | 2008-05-23 | 2013-01-30 | 杭州华三通信技术有限公司 | Telecommunication Ethernet system and repeater |
| CN101488795B (en) * | 2009-01-08 | 2014-01-08 | 中邮科通信技术股份有限公司 | Optical fiber digital transmission method applied on straight-forward station |
| CN101882950B (en) * | 2009-05-06 | 2013-05-01 | 京信通信系统（中国）有限公司 | WIMAX radio frequency far end system supporting MIMO |
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