CN101959326A - Digital optic-fiber repeater - Google Patents
Digital optic-fiber repeater Download PDFInfo
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- CN101959326A CN101959326A CN2009100547915A CN200910054791A CN101959326A CN 101959326 A CN101959326 A CN 101959326A CN 2009100547915 A CN2009100547915 A CN 2009100547915A CN 200910054791 A CN200910054791 A CN 200910054791A CN 101959326 A CN101959326 A CN 101959326A
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Abstract
The invention relates to a repeater applied to a mobile communication system, namely a digital optic-fiber repeater system. The digital optic-fiber repeater system comprises a relay end machine and a remote end machine, wherein the relay end machine comprises a digital intermediate frequency unit 1, a digital processing unit 1, a digital transmission unit 1 and a monitoring unit 1; the remote end machine comprises a radio frequency unit 2, a digital intermediate frequency unit 2, a digital processing unit 2, a digital transmission unit 2 and a monitoring unit 2; the digital intermediate frequency unit 1 mixes a radio frequency signal and a radio frequency local oscillator, outputs a simulated intermediate frequency signal, and converts the simulated intermediate signal into a digital intermediate frequency signal through A/D conversion; the digital processing unit 1 realizes extraction, modulation and filtering of the digital signal by controlling data stream through an FPGA; the digital transmission unit 1 realizes the optical transmission of a digital baseband signal; the radio frequency unit 2 realizes power amplification of the radio frequency signal and low-noise reception of a small signal; a power supply unit 1 provides power for the relay end machine; the monitoring unit 1 realizes local and remote monitoring and control; and the relay end machine and the remote end machine communicate with each other through an optical fiber.
Description
Technical field
The present invention relates to mobile communication system, relate in particular to a kind of digital optical fiber direct station that is applied to mobile communication system.
Background technology
Along with mobile communication rapid development, GSM and cdma network construction speed are accelerated again and again, and the dilatation of network, the increase of base station number make that covering is more complete, therefore also bring the increase of number of users and rapidly increasing progressively of telephone traffic.When people use mobile phone in a large number, also the service quality to network proposes higher requirement, all mobile communications networks, all adopted the mode of radio communication to transmit signal, a wireless coverage network is constructed in the base station of utilize to distribute building, and makes between mobile phone and base station unobstructed enforcement to communicate by letter.In order in a zone, to set up the network of seamless covering, need to build the base station of some, building the base station needs a large amount of inputs, constantly the setting up of base station, increase the complexity of radio signal propagation again for network, careless slightlyly caused mutual interference easily.Therefore, how to make Internet resources reasonable configuration and application, network optimization work has become mobile communication carrier and has improved service level, ensure the important process content of communication quality, in the process of networking, though the density of base station increases again and again, the orientation of antenna is adjusted again and again, blind area or weak district that the congested or signal of some regional signals is still still arranged, this is that the telephone traffic of base station is broken through again and again on the one hand, also be that base station power can't arbitrarily strengthen on the other hand, yet exist simultaneously some special landform and be difficult to cover and require the degree of depth of indoor signal to cover.Simple increase base station is difficult to prove effective, and often needs to use various types of repeaters to go to replenish the blind area, enlarges to cover.
The repeater, as a kind of two-way amplifier that technology constituted that utilizes radio frequency to amplify, its major technique comprises: linear power amplification, noiselike signal reception, spurious signal filtering etc.The repeater by donor antenna pickoff signals in existing overlay area, base station,, is transmitted into the signal of filtering once more after power amplifier amplifies and treats the overlay area carrying out fabulous isolation with logical outer signal by band pass filter in down link.In the uplink path, the signal of the travelling carriage mobile phone in the overlay area is transmitted into corresponding base station with same working method after by up amplification link processing, thereby reaches the signal transmission of base station and mobile phone.
Enormous function has been brought into play in the repeater in the construction of mobile radio communication, at present GSM network, in cdma network and the PHS network, can find the application of various repeaters.A large amount of application show, in the covering system of repeater in the network optimization, have remedied the base station and have covered defect of insufficient, have formed new covering means.
The repeater that is used for coverage optimization has polytype to use, and modal have: with the covering amplifier is extended in wireless discharging-directly station, Optical Fiber Transmission repeater, frequency-shift repeater, base station frequently.
Wireless intra-frequency repeater, this is modal a kind of repeater, low being easy to of equipment cost installed, especially convenient resettlement, be to mend the method blind, that the increase coverage territory is the easiest, if but with the improper interference that very easily causes the base station of wireless discharging-directly station accent survey frequently, especially in cdma system, this phenomenon is more obvious.Therefore when access network, pay special attention to.For the communication network that adopts the PHS mode, owing to adopted the duplex mode of TDD, the up-downlink direction signal frequency of intra-frequency repeater is identical, and the straight discharge signal of this moment needs clock switch and controls amplifying signal, otherwise just is easy to generate self-excitation.
Optical fiber repeater is the repeater of thinking more stable in using at present, it need use optical fiber that base station signal is connected in the direct discharging station, signal source is purer, generally is not easy big net is formed interference, will control the bottom noise level of access base station during optical fiber repeater uses.When using for indoor covering, when the access of high-lager building employing optical fiber occurring, sometimes for the telephone traffic between each sector of balance, the optical fiber repeater that also can adopt many sectors to insert.
Frequency-shift repeater because cdma network in use, still has idle frequency in the band, when not having fiber resource, has just had the wireless discharging-directly station that constitutes with the shift frequency mode.This method is in the process of shift frequency transmission, and therefore the frequency-independent that the frequency of use and whole network use, can not increase the interference signal to big net.A kind of trend is arranged recently: be exactly to utilize the shift frequency mode to solve the signal source of the indoor distribution of urban inner.The signal that shift frequency is introduced from the base station is launched after frequency conversion, its frequency has been avoided the current frequency of utilization of mobile radio communication, the space can not increase identical frequency content, communication quality to the assurance network obviously is useful, this method, the cost increase is also few, should be the signal introducing method that indoor radio signal source is recommended employing in the urban district.
Base station also is that a kind of radiofrequency signal is directly put equipment, and it generally connects together with the base station, mainly is to be used for directly enlarging the coverage (amplification downstream signal) of base station, and polygamy connects tower amplifier and amplifies upward signal during application.This equipment is applied in suburb, remote countryside more, is used for the traffic capacity affluence but the base station of coverage deficiency.
There are many problems in existing repeater in application, along with the transmission range increase, it is very big to decay when signal power arrives the overlay area on the transmission range, can't satisfy large tracts of land, long distance covering requirement; On networking mode, networking mode is single, can only adopt the far-end parallel way, has limited its application under multiple covering occasion; The noise stack, when band Duo Tai repeater, base station, the noise stack causes the bigger lifting of base station back noise, causes the link imbalance; On the time dispersive, influenced by propagation delay time, can not adopt same sector signals that design difficulty is strengthened overlapping covered, and artificial the introducing switched more.
Summary of the invention
The purpose of this invention is to provide a kind of digital optical fiber direct station.
For achieving the above object, just provide a kind of digital optical fiber repeater system specifically, comprise relaying terminal and remote termination, the relaying terminal comprises digital intermediate frequency unit one, digital processing element one, Digital Transmission unit one and monitoring unit one, remote termination comprises radio frequency unit two, digital intermediate frequency unit two, digital processing element two, Digital Transmission unit two and monitoring unit two, described digital intermediate frequency unit one is with radiofrequency signal and radio-frequency (RF) local oscillator mixing output analog if signal, convert described analog if signal to digital medium-frequency signal through A/D again, described digital processing element one is realized digital signal extraction the control of data flow by FPGA, modulation, Filtering Processing, the optical transmission of digital baseband signal is realized in described Digital Transmission unit one, described radio frequency unit two is realized the power amplification of radiofrequency signal, the low noise of small-signal receives, described power subsystem one provides power supply for described relaying terminal, described monitoring unit one realizes that described relaying terminal and remote termination communicate by optical fiber to local and remote supervision and control.
Adopt technical scheme of the present invention, digital optical fiber direct station is compared with traditional repeater and is had new feature, signal is not decayed with the decay of light signal: in analogue transmission, radiofrequency signal decays along with the decay of light signal, has so just limited the transmission range of analog optical fiber repeater greatly; And in the Digital Transmission process, radiofrequency signal does not decay with the decay of light signal, keeps dynamic range constant in long distance and demultiplex transmission system, makes the design of optical fiber repeater, debugging become more convenient.The shunt of signal is closed the road and do not decayed with the decay of light signal: descending shunt is by the realization of duplicating of digital bit stream, and the up road of closing is by numeral and realization, and digital demultiplexing closes the road signal is not had any loss.Digital Transmission is not subjected to the dispersive influence of light: in the analog optical fiber repeater, time dispersive is the principal element of the overlapping area of coverage communication effect of influence, and in Digital Transmission, owing to be subjected to the dispersive influence of light little, so (0.5KM) can adopt multimode fiber when short-distance transmission.The reliability height of digital fiber: because the MTBF time of digital light device is long, working stability, so reduced maintenance cost.
Description of drawings
Fig. 1 is the theory diagram of one embodiment of the invention
Embodiment
Specify technical scheme of the present invention below in conjunction with drawings and Examples.
Adopt following scheme to realize technical scheme in the specific embodiment of the present invention: the coffret of CPRI standard: radiofrequency signal is not constant with the decay of the light signal maintenance dynamic range that decays in long distance and demultiplex transmission system; The error rate of transmission is less than 10exp-12; Avoiding up radiofrequency signal to bring out optical transceiver excessively by force, saturated to avoid up radiofrequency signal to bring out optical transceiver excessively by force saturated.Software and radio technique: can be by increasing software module, being easy to increases new function, has very strong flexibility; Standardization, modular structure, its hardware can upgrade or expand along with the development of device and technology, and software is with the need and constantly upgrading also; At numeric field signal is handled the very big equipment that strengthened to Signal Processing and control ability; Follow the tracks of the signal of handling each carrier frequency, each time slot with the ns stage speed, realize time slot A GC and noise suppressing function.High-power high Linear Power Amplifier technology: surpass microcellulor when guaranteeing that overloading zooms out frequently and approach the covering power of base station; Every carrier frequency output can reach 7W when using high Linear Power Amplifier 8 carrier frequency of 60W; Cooperate the uplink downlink balance when having realized high-power covering to support EDGE network to cover requirement fully with the upstream noise control technology.Feedforward linear power amplifier: in feedforward linear power amplifier, pilot signal at different technology and a kind of correspondence of requirement design, energy according to pilot signal is controlled vector modulator by the algorithm of inside, thereby reaches the spectral re-growth component that counteracting is introduced by main power amplifier.Digital pre-distortion power amplifying: the basic ideas of this method are to make the PA predistortion, like this will distortion when the PA when transmission signals, and satisfy the requirement of transmission template (mask).Digital filtering technique: adopt Large N FIR digital filter, compare with traditional analog filter such as Surface Acoustic Wave Filter and have good stability, this is because it depends primarily on software systems and is not subjected to natural environment influence.Next has very strong flexibility, and is measurable, can repeat.And being different from analogue system all is to be built by element, and digital filtering all is that the very high chip volume of integrated level is little, low in energy consumption owing to what use.Certainly the system performance index that most importantly digital filter reached is that Surface Acoustic Wave Filter is beyond one's reach far away.Digital IF Processing: receiving terminal ADC directly samples to intermediate-freuqncy signal, and I/Q demodulation, extraction, filtering are carried out by digital down converter in the sampling back, are sent to Base-Band Processing then.Transmitting terminal, baseband signal carry out the D/A conversion after modulating through interpolation, filtering, I/Q, become analog intermediate frequency signal.Digital modulation and demodulation: digital intermediate frequency I/Q modulation has reduced the analogue device in the transceiver, effectively avoids i/q signal amplitude imbalance, unbalance in phase; Reduce the analogue device of transceiver, also just reduce harmful effects such as temperature drift, increase the reliability and the consistency of system.
Adopt the technical program, up employing diversity receiving technology, anti-fading property is stronger; Adopt digital processing technology, and high speed, big dynamic ADC and DAC technology, the signal to noise ratio height, transmission quality is reliable and stable; High Linear Power Amplifier output is obvious at the EDGE network application advantage; Adopt the digital optical signal transmission technology, the optical device burn-in effects is little; Under the prerequisite that does not reduce signal quality, allow bigger optical path loss Overall Power Consumption low, the back-up source configuration is simple, investment is little; Not influenced by light path, equipment debugging is simple, monitoring is convenient; Has noise suppressing function: separately the upstream noise of each Remote Radio Unit is controlled; Greatly reduce the phase mutual interference of upstream noise between each Remote Radio Unit; Thoroughly eliminate the influence of upstream noise to the base station.Automatic delay is adjusted function in addition: measure the time delay between each capped end and the incoming end in real time; The energy automatic or manual is adjusted the time delay between each capped end and the incoming end; Elimination is disturbed with the delay dispersion of overlapped signal overlay area between the capped end of sector.Networking mode is changeable simultaneously.
Claims (1)
1. digital optical fiber repeater system, comprise relaying terminal and remote termination, it is characterized in that, the relaying terminal comprises digital intermediate frequency unit one, digital processing element one, Digital Transmission unit one and monitoring unit one, remote termination comprises radio frequency unit two, digital intermediate frequency unit two, digital processing element two, Digital Transmission unit two and monitoring unit two, described digital intermediate frequency unit one is with radiofrequency signal and radio-frequency (RF) local oscillator mixing output analog if signal, convert described analog if signal to digital medium-frequency signal through A/D again, described digital processing element one is realized digital signal extraction the control of data flow by FPGA, modulation, Filtering Processing, the optical transmission of digital baseband signal is realized in described Digital Transmission unit one, described radio frequency unit two is realized the power amplification of radiofrequency signal, the low noise of small-signal receives, described power subsystem one provides power supply for described relaying terminal, described monitoring unit one realizes that described relaying terminal and remote termination communicate by optical fiber to local and remote supervision and control.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100547915A CN101959326A (en) | 2009-07-14 | 2009-07-14 | Digital optic-fiber repeater |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009100547915A CN101959326A (en) | 2009-07-14 | 2009-07-14 | Digital optic-fiber repeater |
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| CN101959326A true CN101959326A (en) | 2011-01-26 |
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| CN2009100547915A Pending CN101959326A (en) | 2009-07-14 | 2009-07-14 | Digital optic-fiber repeater |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103648121A (en) * | 2013-12-26 | 2014-03-19 | 中国电子科技集团公司第四十一研究所 | Method for signal detection of mobile terminal and monitoring of terminal equipment and device |
| CN104536352A (en) * | 2015-01-07 | 2015-04-22 | Comlab（北京）通信系统设备有限公司 | Power amplifier device used for repeater |
| CN110784265A (en) * | 2019-10-22 | 2020-02-11 | 京信通信系统（中国）有限公司 | Method and device for opening station of optical fiber distribution system, optical fiber distribution system and storage medium |
-
2009
- 2009-07-14 CN CN2009100547915A patent/CN101959326A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103648121A (en) * | 2013-12-26 | 2014-03-19 | 中国电子科技集团公司第四十一研究所 | Method for signal detection of mobile terminal and monitoring of terminal equipment and device |
| CN104536352A (en) * | 2015-01-07 | 2015-04-22 | Comlab（北京）通信系统设备有限公司 | Power amplifier device used for repeater |
| CN110784265A (en) * | 2019-10-22 | 2020-02-11 | 京信通信系统（中国）有限公司 | Method and device for opening station of optical fiber distribution system, optical fiber distribution system and storage medium |
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Application publication date: 20110126 |