CN107889120B - Indoor coverage system for improving TDD-LTE uplink interference immunity - Google Patents

Indoor coverage system for improving TDD-LTE uplink interference immunity Download PDF

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CN107889120B
CN107889120B CN201711181968.9A CN201711181968A CN107889120B CN 107889120 B CN107889120 B CN 107889120B CN 201711181968 A CN201711181968 A CN 201711181968A CN 107889120 B CN107889120 B CN 107889120B
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signal
uplink
downlink
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lte
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CN107889120A (en
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王全华
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Ankexun Fujian Technology Co ltd
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W16/00Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/18Network planning tools
    • H04W16/20Network planning tools for indoor coverage or short range network deployment
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413MIMO systems

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Abstract

The invention provides a TDD-LTE multi-input multi-output indoor coverage system, which comprises: the system comprises an active near-end machine and a far-end active antenna which are directly coupled and connected with an RRU antenna port, wherein the active near-end machine is connected with the far-end active antenna through an indoor signal distribution system; the invention adopts a high-directivity directional coupler and uplink signal amplitude limiting processing to solve the problem of uplink interference of the traditional envelope detection level trigger synchronization scheme. And the scheme of sharing the frequency converter by uplink and downlink is adopted, so that the circuit design is simplified, the equipment cost is fully reduced, and the cost performance of the product is improved without sacrificing the system performance.

Description

Indoor coverage system for improving TDD-LTE uplink interference immunity
The application is a divisional application of a parent application named as 'a TDD-LTE multiple-input multiple-output indoor coverage system' with the application number of 201410562363.4 and the application date of 2014.10.21.
Technical Field
The invention relates to the technical field of communication equipment, in particular to a TDD-LTE multi-input multi-output indoor coverage system.
Background
With the development of information technology, people have increasingly demanded network communication technology, and in order to meet the increasingly high data communication service requirements for high data traffic communication including data, voice, image and other contents, 4G communication is developing more and more rapidly in recent years due to the technical advantage of high speed. At present, the development of a commercial network and an industrial chain of TD-LTE (time division Long term evolution) 4G communication which is being vigorously developed in China is gradually mature. As one of the key technologies of the 4G LTE communication standard, a Multiple-Input Multiple-Output (MIMO) antenna technology is to use Multiple antennas at a transmitting end and a receiving end to transmit and receive data, so as to improve the capacity of a channel, improve the reliability of the channel, and reduce the error rate. However, in the conventional 2G and 3G indoor coverage systems, a Single-Input Single-Output (SISO) mode is adopted, and currently, for the improvement of the existing indoor distribution system, a scheme of frequency conversion transmission is mainly adopted, taking a dual-channel MIMO system which is mainly applied at present as an example, that is, a first path of signal is directly transmitted while being kept unchanged, and a second path of signal is converted to a different frequency band for different-frequency transmission.
One of the key technologies of the TD-LTE indoor coverage system adopting the frequency conversion scheme is to keep real-time synchronization with base station equipment, while the envelope detection level trigger synchronization scheme with the advantage of higher cost exists the problem that when an uplink output signal is stronger, the uplink and downlink judgment of synchronous detection is interfered, so that synchronous control is switched by mistake, and the reliability is poor.
In the prior art, a method, a device and a system for realizing multi-input multi-output signal transmission are disclosed, and the disclosure number is: 102882573A, published as: 2013-01-16; the embodiment of the invention provides a method, a device and a system for realizing multi-input multi-output signal transmission, which comprises the following steps: the method comprises the steps of modulating N paths of signals with the same frequency sent by a base station or a multi-input multi-output antenna array to generate N paths of modulated signals with different frequencies, and transmitting the signals by using the same feeder line distribution system. The N modulation signals with different frequencies transmitted in the feeder line distribution system can be demodulated into N signals with the same frequency and are accessed to a base station or a multi-input multi-output antenna array, so that the problem that in the prior art, in the time division duplex multi-input multi-output based signal transmission process, the signals with the same frequency in the N paths are transmitted through N different feeder line distribution systems to cause the signal transmission to be complex is solved. The envelope detection level trigger synchronization scheme of the patent can cause the error switching of the synchronization control when the uplink output signal is strong; the scheme of the application performs further circuit optimization aiming at uplink interference, and greatly improves the synchronous anti-interference performance.
The prior art also discloses a novel TD-LTE room division MIMO frequency conversion system, which has the following publication number: 202535360U, published as: 2012-11-14; the novel TD-LTE indoor MIMO frequency conversion system capable of realizing complete synchronization or minimization of time delay of a frequency conversion system and a base station and avoiding interference of other systems to the system comprises a near-end machine and a far-end machine, wherein the output end of the near-end machine and the input end of the far-end machine are connected through a feeder system, the near-end machine comprises a radio frequency signal transmission channel with the same multi-channel transmission mode, a combiner and a monitoring center unit, the far-end machine comprises a combiner, a radio frequency signal transmission channel with the same multi-channel transmission mode, an antenna and a monitoring center unit, the envelope of a downlink radio frequency signal in the radio frequency signal transmission channel is detected and shaped through an envelope shaping unit and sent to a control unit, the control unit is compared with a built-in working mode of the control unit, and the control unit selects a working mode to output a synchronous control code to enable. The patent adopts an independent design of an uplink frequency converter and a downlink frequency converter; the application document aims at a TDD-LTE time division duplex system, and the application document adopts an uplink and downlink shared frequency converter.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a TDD-LTE (time division duplex) multiple-input multiple-output indoor coverage system, which adopts a high-directivity directional coupler and uplink signal amplitude limiting processing to solve the problem of uplink interference in the conventional envelope detection level trigger synchronization scheme.
The invention is realized by the following steps: a TDD-LTE multiple-input multiple-output indoor coverage system, the system comprising: the system comprises an active near-end machine and a far-end active antenna which are directly coupled and connected with an RRU antenna port, wherein the active near-end machine is connected with the far-end active antenna through an indoor signal distribution system;
the active near-end machine includes: the first filter, the second filter, the third filter, the first directional coupler, the first packet detection and synchronization control unit, the first uplink amplification unit, the first downlink amplification unit, the first RF switch, the second RF switch, the first frequency conversion unit and the first combiner/splitter; the remote active antenna includes: the second combiner/splitter, a fourth filter, a fifth filter, a sixth filter, a seventh filter, a second frequency conversion unit, a second directional coupler, a second envelope detection and synchronization control unit, a second uplink amplification unit, a second downlink amplification unit, a third RF switch, a fourth RF switch, a second frequency conversion unit, a first MIMO antenna and a second MIMO antenna;
the port 1 of the RRU antenna port is connected with a second filter, and the second filter and a third filter are both connected with a first combiner/splitter; a port 2 of an RRU antenna port is connected with a first directional coupler through a first filter, and the first directional coupler is respectively connected with a first envelope detection and synchronization control unit and a first RF switch; the first RF switch is respectively connected with the first envelope detection and synchronization control unit, the first uplink amplification unit and the first downlink amplification unit; the first uplink amplifying unit and the first downlink amplifying unit are connected with the second RF switch, and the first uplink amplifying unit, the first downlink amplifying unit and the second RF switch are all connected with the first envelope detection and synchronization control unit; the second RF switch is connected with the third filter through the first frequency conversion unit; the first combiner/divider is connected with the second combiner/divider through the indoor signal distribution system;
the second combiner/divider is connected with the first MIMO antenna through a fifth filter; the second combiner/splitter, the fourth filter, the second frequency conversion unit, the second directional coupler and the third RF switch are sequentially connected; the second directional coupler is connected with the second envelope detection and synchronization control unit through a sixth filter; the third RF switch is respectively connected with the second uplink amplifying unit and the second downlink amplifying unit; the fourth RF switch is respectively connected with the second uplink amplifying unit, the second downlink amplifying unit and the seventh filter; the second envelope detection and synchronization control unit is respectively connected with the third RF switch, the second uplink amplification unit and the fourth RF switch; the seventh filter is connected with the second MIMO antenna; by the cooperation of the active near-end machine, the indoor signal distribution system and the far-end active antenna, the uplink anti-interference in the envelope detection level trigger synchronization mode is realized.
Furthermore, the first filter, the second filter and the third filter all adopt band-pass filters with high suppression capability to filter out-of-band unwanted signals; the first directional coupler receives a downlink input signal in a directional coupling mode; the first envelope detection and synchronization control unit comprises a radio frequency detection circuit, an envelope signal shaping circuit and an uplink and downlink synchronization control unit which are connected in sequence, envelope detection tracking of downlink signals is realized, uplink and downlink judgment is carried out by triggering of a threshold level, and uplink and downlink synchronization control signals are finally output; the first uplink amplifying unit comprises a numerical control attenuator, a post-stage amplifying unit and an amplitude limiter, wherein the amplitude limiter is used for quickly starting and controlling when an uplink signal is too large to exceed rated output power, so that the final output power is not beyond the rated power, and the phenomenon that the first envelope detection and synchronization control unit is interfered due to the fact that the uplink output signal is too large to cause synchronous switching misoperation is avoided; the first downlink amplifying unit comprises a numerical control attenuator and a driving amplifying unit; the first RF switch and the second RF switch realize the signal receiving and transmitting switching of an uplink and a downlink of a time division duplex system; the first frequency conversion unit comprises a frequency mixer and a local oscillation circuit; the first combiner/splitter combines a first path of non-frequency-conversion TDD-LTE downlink signal and a second path of frequency-conversion TDD-LTE downlink signal, and transmits the combined signals to the far-end active antenna through the feeder line, and separates two paths of TDD-LTE uplink signals transmitted by the far-end active antenna through the feeder line, and then transmits the separated signals to a first path of non-frequency-conversion channel and a second path of frequency-conversion channel.
Furthermore, the fourth filter, the fifth filter, the sixth filter and the seventh filter all adopt band-pass filters with high suppression capability, and are used for filtering out-of-band unwanted signals; the second directional coupler receives a downlink input signal in a directional coupling mode; the second envelope wave detection and synchronization control unit and the first envelope wave detection and synchronization control unit have the same structure and function; the second combiner/splitter realizes that two paths of TDD-LTE downlink signals transmitted by the active near-end machine through the feeder line are separated and then transmitted to the first path of non-frequency conversion channel and the second path of frequency conversion channel, and the first path of non-frequency conversion TDD-LTE uplink signal and the second path of frequency conversion TDD-LTE uplink signal are combined and then transmitted to the active near-end machine through the feeder line; the second uplink amplifying unit comprises a low-noise amplifying unit, a numerical control attenuator, a middle-stage amplifying unit and an amplitude limiter which are connected in sequence; the second downlink amplifying unit comprises a numerical control attenuator, a driving amplifying unit and a power amplifying unit which are connected in sequence; the third RF switch and the fourth RF switch realize the signal receiving and transmitting switching of the uplink and the downlink of the time division duplex system; the second frequency conversion unit comprises a frequency mixer and a local oscillation circuit; the first MIMO antenna and the second MIMO antenna adopt vertical and horizontal dual polarization design so as to greatly improve the irrelevance between the two-channel signals of the MIMO antenna in a compact space.
Further, the above-mentioned cooperation through active near-end machine, indoor signal distribution system and far-end active antenna realizes that envelope detection level triggers anti-interference of ascending in the synchronous mode, specifically:
in the active near-end machine, a first channel of non-frequency conversion channel transmits TDD-LTE downlink signals output by an RRU port 1 to a far-end active antenna through a feeder line of an indoor signal distribution system through a first combiner/splitter after band-pass filtering of out-of-band useless clutter signals by a second filter; the signal from the far end is separated into a first path of non-frequency-conversion TDD-LTE uplink signal through a first combiner/splitter, and the first path of non-frequency-conversion TDD-LTE uplink signal is subjected to band-pass filtering through a second filter and then is transmitted to an RRU port 1;
the second path is a frequency conversion channel, the TDD-LTE downlink signal output by the RRU port 2 is subjected to band-pass filtering by a first filter and then output to a first directional coupler, the coupled signal is output to a first envelope detection and synchronization control unit through a coupling port of the first directional coupler, an analog envelope signal is output by a radio frequency detection circuit, and after waveform shaping processing is carried out by a high-speed comparator, an uplink and downlink synchronous control unit converts and outputs uplink and downlink transceiving switching control signals required by a first uplink and downlink amplification unit and a second RF switch module;
when the TDD-LTE RRU works in a downlink, the first RF switch is switched to a downlink, and meanwhile, the first downlink amplification unit is started and the first uplink amplification unit is closed; the TDD-LTE downlink signal output by the RRU port 2 passes through a first filter and a first directional coupling circuit, then enters a first downlink amplifying unit through a first RF switch, namely enters a driving amplifying unit for amplifying after passing through a numerical control attenuator, then enters a frequency mixer for frequency conversion through a second RF switch, the obtained frequency conversion signal is input into a third filter for band-pass filtering, and then is combined with a first path of non-frequency-conversion TDD-LTE downlink signal through a first combiner/splitter and then is transmitted to a far-end active antenna through an indoor signal distribution system; similarly, when the uplink works, the first RF switch is switched to the uplink, and simultaneously the first uplink amplifying unit is turned on, and the first downlink amplifying unit is turned off; an uplink signal transmitted by a far-end active antenna is separated into a second path of frequency conversion signal through a first combiner/splitter, filtered by a third filter and subjected to frequency conversion by a mixer in sequence to be restored into a TDD-LTE uplink signal of the original frequency band, and the TDD-LTE uplink signal is output to a TDD-LTE RRU port 2 through a second RF switch, a numerical control attenuator, a post-stage amplification unit, an amplitude limiter, a first RF switch, a first directional coupler and a first filter;
in the far-end active antenna equipment, a first path of non-frequency-conversion channel separates a first path of non-frequency-conversion TDD-LTE downlink signal from a signal transmitted by an active near-end machine through a second combiner/splitter, and the first path of non-frequency-conversion TDD-LTE downlink signal is output to an MIMO antenna after being subjected to band-pass filtering by a fifth filter and is transmitted to a coverage area; similarly, an uplink signal received by the first MIMO antenna is filtered by the fifth filter, combined by the second combiner/splitter, and transmitted to the active near-end machine through the indoor signal distribution system;
a second channel of frequency conversion channel, which separates a second channel of frequency conversion signal from the signal transmitted by the active near-end machine through a second combiner/splitter, then filters the second channel of frequency conversion signal through a fourth filter, then enters a frequency mixer for frequency conversion processing and restores the frequency conversion processing into a TDD-LTE downlink signal of the original frequency band, outputs the coupled signal to a sixth filter through a coupling port of a second directional coupler for filtering, and then sends the filtered signal to a second envelope detection and synchronization control unit, namely outputs an analog envelope signal through a radio frequency detection circuit, and converts and outputs an uplink and downlink transceiving switching control signal required by a second uplink and downlink amplification unit and a second RF switch module through an uplink and downlink synchronization control unit after waveform shaping processing is carried out through a high-speed comparator;
when the Radio Frequency (RF) switch works in a downlink, the first RF switch is switched to a downlink, the second downlink amplification unit is started, and the second uplink amplification unit is closed; the signals transmitted by the active near-end machine are separated into a second path of frequency conversion signals through a second combiner/splitter, then the second path of frequency conversion signals are filtered through a fourth filter, then the second path of frequency conversion signals enter a frequency mixer for frequency conversion processing and are recovered into TDD-LTE downlink signals of the original frequency band, the TDD-LTE downlink signals pass through a second directional coupler and a third RF switch, enter a second downlink amplification unit, namely enter a driving amplification unit for amplification after passing through a numerical control attenuator, pass through a power amplification unit for high-power amplification, pass through a fourth RF switch to a seventh filter for filtering, and then are output to a MIMO antenna II to be transmitted to a coverage area; similarly, when working in the uplink, TDD-LTE uplink signals received by the MIMO antenna two are filtered by the seventh filter, then transmitted to the second uplink amplifying unit by the fourth RF switch for low noise amplification, that is, sequentially transmitted through the low noise amplifying unit, the numerical control attenuator, the intermediate amplifying unit, and the amplitude limiter, then input to the mixer by the third RF switch and the second directional coupler for frequency conversion into a second channel of frequency conversion signals, filtered by the fourth filter, then combined by the second combiner/splitter, and transmitted to the active near-end machine by the indoor signal distribution system.
Furthermore, the system also comprises a near-end monitoring module which completes the functions of inquiring various parameters, controlling and managing faults of the active near-end machine; and completing the receiving and transmitting communication control of the far-end active antenna; the active near-end machine state information can be transmitted to the monitoring center in a remote mode, and the monitoring center can control and set various parameters of the active near-end machine.
Furthermore, the system also comprises a far-end monitoring module which completes the functions of inquiring various parameters, controlling and managing faults of the far-end active antenna and realizes the transceiving communication with the near-end monitoring module of the active near-end machine through the transmission of the indoor signal distribution system.
The invention has the following advantages: the system of the present invention comprises: the system comprises an active near-end machine and a far-end active antenna which are directly coupled and connected with an RRU antenna port, wherein the active near-end machine is connected with the far-end active antenna through an indoor signal distribution system; the invention adopts a high-directivity directional coupler and uplink signal amplitude limiting processing to solve the problem of uplink interference of the traditional envelope detection level trigger synchronization scheme. And the scheme of sharing the frequency converter by uplink and downlink is adopted, so that the circuit design is simplified, the equipment cost is fully reduced, and the cost performance of the product is improved without sacrificing the system performance.
Drawings
Fig. 1 is a schematic block diagram of an active near-end unit of a TDD-LTE mimo indoor coverage system.
Fig. 2 is a schematic block diagram of a remote active antenna of a TDD-LTE mimo indoor coverage system.
Fig. 3 is a detailed functional block diagram of the active near-end unit.
Fig. 4 is a detailed functional block diagram of a remote active antenna.
Detailed Description
Referring to fig. 1 and fig. 2, a TDD-LTE mimo indoor coverage system of the present invention includes: the system comprises an active near-end machine and a far-end active antenna which are directly coupled and connected with an RRU antenna port, wherein the active near-end machine is connected with the far-end active antenna through an indoor signal distribution system;
the active near-end machine includes: the first filter, the second filter, the third filter, the first directional coupler, the first packet detection and synchronization control unit, the first uplink amplification unit, the first downlink amplification unit, the first RF switch, the second RF switch, the first frequency conversion unit and the first combiner/splitter; the remote active antenna includes: the second combiner/splitter, a fourth filter, a fifth filter, a sixth filter, a seventh filter, a second frequency conversion unit, a second directional coupler, a second envelope detection and synchronization control unit, a second uplink amplification unit, a second downlink amplification unit, a third RF switch, a fourth RF switch, a second frequency conversion unit, a first MIMO antenna and a second MIMO antenna;
the port 1 of the RRU antenna port is connected with a second filter, and the second filter and a third filter are both connected with a first combiner/splitter; a port 2 of an RRU antenna port is connected with a first directional coupler through a first filter, and the first directional coupler is respectively connected with a first envelope detection and synchronization control unit and a first RF switch; the first RF switch is respectively connected with the first envelope detection and synchronization control unit, the first uplink amplification unit and the first downlink amplification unit; the first uplink amplifying unit and the first downlink amplifying unit are connected with the second RF switch, and the first uplink amplifying unit, the first downlink amplifying unit and the second RF switch are all connected with the first envelope detection and synchronization control unit; the second RF switch is connected with the third filter through the first frequency conversion unit; the first combiner/divider is connected with the second combiner/divider through the indoor signal distribution system;
the second combiner/divider is connected with the first MIMO antenna through a fifth filter; the second combiner/splitter, the fourth filter, the second frequency conversion unit, the second directional coupler and the third RF switch are sequentially connected; the second directional coupler is connected with the second envelope detection and synchronization control unit through a sixth filter; the third RF switch is respectively connected with the second uplink amplifying unit and the second downlink amplifying unit; the fourth RF switch is respectively connected with the second uplink amplifying unit, the second downlink amplifying unit and the seventh filter; the second envelope detection and synchronization control unit is respectively connected with the third RF switch, the second uplink amplification unit and the fourth RF switch; the seventh filter is connected with the second MIMO antenna; by the cooperation of the active near-end machine, the indoor signal distribution system and the far-end active antenna, the uplink anti-interference in the envelope detection level trigger synchronization mode is realized.
The first filter, the second filter and the third filter all adopt band-pass filters with high inhibition capacity and are used for filtering out-of-band useless signals; the first directional coupler receives a downlink input signal in a directional coupling mode, and the coupling reception of an uplink output signal is small; the first envelope detection and synchronization control unit comprises a radio frequency detection circuit, an envelope signal shaping circuit and an uplink and downlink synchronization control unit which are connected in sequence, envelope detection tracking of downlink signals is realized, uplink and downlink judgment is carried out by triggering of a threshold level, and uplink and downlink synchronization control signals are finally output; the first uplink amplifying unit comprises a numerical control attenuator, a post-stage amplifying unit and an amplitude limiter, wherein the amplitude limiter is used for quickly starting and controlling when an uplink signal is too large to exceed rated output power, so that the final output power is not beyond the rated power, and the phenomenon that the first envelope detection and synchronization control unit is interfered due to the fact that the uplink output signal is too large to cause synchronous switching misoperation is avoided; the first downlink amplifying unit comprises a numerical control attenuator and a driving amplifying unit; the first RF switch and the second RF switch realize the signal receiving and transmitting switching of an uplink and a downlink of a time division duplex system; the first frequency conversion unit comprises a frequency mixer and a local oscillation circuit; the first combiner/splitter combines a first path of non-frequency-conversion TDD-LTE downlink signal and a second path of frequency-conversion TDD-LTE downlink signal, and transmits the combined signals to the far-end active antenna through the feeder line, and separates two paths of TDD-LTE uplink signals transmitted by the far-end active antenna through the feeder line, and then transmits the separated signals to a first path of non-frequency-conversion channel and a second path of frequency-conversion channel.
The fourth filter, the fifth filter, the sixth filter and the seventh filter all adopt band-pass filters with high inhibition capacity and are used for filtering out-of-band useless signals; the second directional coupler receives the downlink input signal in a directional coupling mode, and the coupling reception of the uplink output signal is small; the second envelope wave detection and synchronization control unit and the first envelope wave detection and synchronization control unit have the same structure and function; the second combiner/splitter realizes that two paths of TDD-LTE downlink signals transmitted by the active near-end machine through the feeder line are separated and then transmitted to the first path of non-frequency conversion channel and the second path of frequency conversion channel, and the first path of non-frequency conversion TDD-LTE uplink signal and the second path of frequency conversion TDD-LTE uplink signal are combined and then transmitted to the active near-end machine through the feeder line; the second uplink amplifying unit comprises a low-noise amplifying unit, a numerical control attenuator, a middle-stage amplifying unit and an amplitude limiter which are connected in sequence; the second downlink amplifying unit comprises a numerical control attenuator, a driving amplifying unit and a power amplifying unit which are connected in sequence; the third RF switch and the fourth RF switch realize the signal receiving and transmitting switching of the uplink and the downlink of the time division duplex system; the second frequency conversion unit comprises a frequency mixer and a local oscillation circuit; the first MIMO antenna and the second MIMO antenna adopt vertical and horizontal dual polarization design so as to greatly improve the irrelevance between the two-channel signals of the MIMO antenna in a compact space.
As shown in fig. 3 and 4, the interference resistance of the uplink in the envelope detection level triggered synchronization mode is realized by the cooperation of the active near-end unit, the indoor signal distribution system, and the far-end active antenna, specifically:
in the active near-end machine, a first channel of non-frequency conversion channel transmits TDD-LTE downlink signals output by an RRU port 1 to a far-end active antenna through a feeder line of an indoor signal distribution system through a first combiner/splitter after band-pass filtering of out-of-band useless clutter signals by a second filter; the signal from the far end is separated into a first path of non-frequency-conversion TDD-LTE uplink signal through a first combiner/splitter, and the first path of non-frequency-conversion TDD-LTE uplink signal is subjected to band-pass filtering through a second filter and then is transmitted to an RRU port 1;
the second path is a frequency conversion channel, the TDD-LTE downlink signal output by the RRU port 2 is subjected to band-pass filtering by a first filter and then output to a first directional coupler, the coupled signal is output to a first envelope detection and synchronization control unit through a coupling port of the first directional coupler, an analog envelope signal is output by a radio frequency detection circuit, and after waveform shaping processing is carried out by a high-speed comparator, an uplink and downlink synchronous control unit converts and outputs uplink and downlink transceiving switching control signals required by a first uplink and downlink amplification unit and a second RF switch module;
when the TDD-LTE RRU works in a downlink, the first RF switch is switched to a downlink, and meanwhile, the first downlink amplification unit is started and the first uplink amplification unit is closed; the TDD-LTE downlink signal output by the RRU port 2 passes through a first filter and a first directional coupling circuit, then enters a first downlink amplifying unit through a first RF switch, namely enters a driving amplifying unit for amplifying after passing through a numerical control attenuator, then enters a frequency mixer for frequency conversion through a second RF switch, the obtained frequency conversion signal is input into a third filter for band-pass filtering, and then is combined with a first path of non-frequency-conversion TDD-LTE downlink signal through a first combiner/splitter and then is transmitted to a far-end active antenna through an indoor signal distribution system; similarly, when the uplink works, the first RF switch is switched to the uplink, and simultaneously the first uplink amplifying unit is turned on, and the first downlink amplifying unit is turned off; an uplink signal transmitted by a far-end active antenna is separated into a second path of frequency conversion signal through a first combiner/splitter, filtered by a third filter and subjected to frequency conversion by a mixer in sequence to be restored into a TDD-LTE uplink signal of the original frequency band, and the TDD-LTE uplink signal is output to a TDD-LTE RRU port 2 through a second RF switch, a numerical control attenuator, a post-stage amplification unit, an amplitude limiter, a first RF switch, a first directional coupler and a first filter;
the system also comprises a near-end monitoring module which completes the functions of inquiring, controlling and managing various parameters of the active near-end machine; and completing the receiving and transmitting communication control of the far-end active antenna; the active near-end machine state information can be transmitted to the monitoring center in a remote mode, and the monitoring center can control and set various parameters of the active near-end machine.
As shown in fig. 4, in the far-end active antenna device, the first channel of non-frequency-conversion channel separates a first channel of non-frequency-conversion TDD-LTE downlink signal from the signal transmitted by the active near-end machine through the second combiner/splitter, and outputs the first channel of non-frequency-conversion TDD-LTE downlink signal to the MIMO antenna after band-pass filtering by the fifth filter, and transmits the first channel of non-frequency-conversion TDD-LTE downlink signal to the coverage area; similarly, an uplink signal received by the first MIMO antenna is filtered by the fifth filter, combined by the second combiner/splitter, and transmitted to the active near-end machine through the indoor signal distribution system;
a second channel of frequency conversion channel, which separates a second channel of frequency conversion signal from the signal transmitted by the active near-end machine through a second combiner/splitter, then filters the second channel of frequency conversion signal through a fourth filter, then enters a frequency mixer for frequency conversion processing and restores the frequency conversion processing into a TDD-LTE downlink signal of the original frequency band, outputs the coupled signal to a sixth filter through a coupling port of a second directional coupler for filtering, and then sends the filtered signal to a second envelope detection and synchronization control unit, namely outputs an analog envelope signal through a radio frequency detection circuit, and converts and outputs an uplink and downlink transceiving switching control signal required by a second uplink and downlink amplification unit and a second RF switch module through an uplink and downlink synchronization control unit after waveform shaping processing is carried out through a high-speed comparator;
when the Radio Frequency (RF) switch works in a downlink, the first RF switch is switched to a downlink, the second downlink amplification unit is started, and the second uplink amplification unit is closed; the signals transmitted by the active near-end machine are separated into a second path of frequency conversion signals through a second combiner/splitter, then the second path of frequency conversion signals are filtered through a fourth filter, then the second path of frequency conversion signals enter a frequency mixer for frequency conversion processing and are recovered into TDD-LTE downlink signals of the original frequency band, the TDD-LTE downlink signals pass through a second directional coupler and a third RF switch, enter a second downlink amplification unit, namely enter a driving amplification unit for amplification after passing through a numerical control attenuator, pass through a power amplification unit for high-power amplification, pass through a fourth RF switch to a seventh filter for filtering, and then are output to a MIMO antenna II to be transmitted to a coverage area; similarly, when working in the uplink, TDD-LTE uplink signals received by the MIMO antenna two are filtered by the seventh filter, then transmitted to the second uplink amplifying unit by the fourth RF switch for low noise amplification, that is, sequentially transmitted through the low noise amplifying unit, the numerical control attenuator, the intermediate amplifying unit, and the amplitude limiter, then input to the mixer by the third RF switch and the second directional coupler for frequency conversion into a second channel of frequency conversion signals, filtered by the fourth filter, then combined by the second combiner/splitter, and transmitted to the active near-end machine by the indoor signal distribution system.
The system also comprises a far-end monitoring module which completes the functions of inquiring, controlling and managing various parameters of the far-end active antenna and realizes the transceiving communication with the near-end monitoring module of the active near-end machine through the transmission of the indoor signal distribution system.
Although specific embodiments of the invention have been described above, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the appended claims.

Claims (5)

1. An indoor coverage system for improving TDD-LTE uplink interference immunity, the system comprising: the system comprises an active near-end machine and a far-end active antenna which are directly coupled and connected with an RRU antenna port, wherein the active near-end machine is connected with the far-end active antenna through an indoor signal distribution system;
the active near-end machine is used for the first channel of non-frequency conversion channel to transmit the TDD-LTE downlink signal output by the RRU port 1 to the far-end active antenna through the first combiner/splitter by the feeder line of the indoor signal distribution system; a first path of TDD-LTE uplink signal which is not subjected to frequency conversion is separated from a signal sent by a far-end active antenna through a first combiner/splitter and then is transmitted to an RRU port 1;
the second path of frequency conversion channel is also used for filtering and then performing directional coupling on a TDD-LTE downlink signal output by the RRU port 2, then transmitting the coupled signal to the first envelope detection and synchronization control unit, outputting an analog envelope signal through the radio frequency detection circuit, and outputting an uplink and downlink receiving and transmitting switching control signal through uplink and downlink synchronization control conversion after waveform shaping processing;
the RRU is also used for switching the first RF switch to a downlink when the RRU works in a downlink, and simultaneously starting the first downlink amplifying unit and closing the first uplink amplifying unit; the TDD-LTE downlink signal output by the RRU port 2 is subjected to directional coupling, is subjected to numerical control attenuation and then is amplified, and then enters a frequency mixer for frequency conversion treatment, and the obtained frequency conversion signal is combined with a first path of non-frequency-conversion TDD-LTE downlink signal by a first combiner/splitter and then is transmitted to a far-end active antenna through an indoor signal distribution system; when the RRU works in an uplink, the first RF switch is switched to an uplink, and meanwhile, the first uplink amplifying unit is started, and the first downlink amplifying unit is closed; an uplink signal transmitted by a far-end active antenna is separated into a second path of frequency conversion signal by a first combiner/splitter, and the second path of frequency conversion signal is restored into a TDD-LTE uplink signal of the original frequency band after filtering and frequency conversion in sequence, and is output to an RRU port 2 after numerical control attenuation, post-stage amplification, amplitude limiting, a directional coupler and a filter;
the far-end active antenna is used for a first channel of non-frequency conversion channel, separates a first channel of non-frequency conversion TDD-LTE downlink signal from the signal transmitted by the active near-end machine through a second combiner/splitter, and outputs the signal to the MIMO antenna after filtering and transmits the signal to a coverage area; after being filtered, an uplink signal received by the MIMO antenna I is combined by the second combiner/splitter and then is transmitted to the active near-end machine through the indoor signal distribution system;
the second path of frequency conversion channel is also used for separating a second path of frequency conversion signal from the signal transmitted by the active near-end machine through the second combiner/splitter, then the second path of frequency conversion signal is restored into a TDD-LTE downlink signal of the original frequency band through filtering and frequency conversion processing, the coupled signal is output through the directional coupler, then the coupled signal is sent to the second envelope detection and synchronization control unit, an analog envelope signal is output through the radio frequency detection circuit, and after waveform shaping processing, the uplink and downlink synchronization control unit converts and outputs an uplink and downlink transceiving switching control signal;
the RRU is also used for switching the first RF switch to a downlink when the RRU works in a downlink, simultaneously starting the second downlink amplifying unit and closing the second uplink amplifying unit; separating the signal transmitted by the active near-end machine into a second path of frequency conversion signal through a second combiner/splitter, filtering, performing frequency conversion processing again to restore the signal to a TDD-LTE downlink signal of the original frequency band, performing directional coupling to amplify the signal at high power, filtering, outputting the signal to a MIMO antenna II and transmitting the signal to a coverage area; when the RRU works in an uplink, TDD-LTE uplink signals received by the MIMO antenna II are subjected to low-noise amplification after being filtered, then are converted into second variable frequency signals through the directional coupler, are filtered, are combined through the second combiner/splitter, and are transmitted to the active near-end machine through the indoor signal distribution system.
2. The indoor coverage system for improving uplink interference immunity of TDD-LTE according to claim 1, wherein: the first envelope detection and synchronization control unit comprises a radio frequency detection circuit, an envelope signal shaping circuit and an uplink and downlink synchronization control unit which are connected in sequence, envelope detection tracking of downlink signals is realized, uplink and downlink judgment is carried out by triggering of a threshold level, and uplink and downlink synchronization control signals are finally output; the first combiner/splitter combines a first path of non-frequency-conversion TDD-LTE downlink signal and a second path of frequency-conversion TDD-LTE downlink signal, and transmits the combined signals to the far-end active antenna through the feeder line, and separates two paths of TDD-LTE uplink signals transmitted by the far-end active antenna through the feeder line, and then transmits the separated signals to a first path of non-frequency-conversion channel and a second path of frequency-conversion channel.
3. The indoor coverage system for improving uplink interference immunity of TDD-LTE according to claim 2, wherein: the second envelope wave detection and synchronization control unit and the first envelope wave detection and synchronization control unit have the same structure and function; the second combiner/splitter realizes that two paths of TDD-LTE downlink signals transmitted by the active near-end machine through the feeder line are separated and then transmitted to the first path of non-frequency conversion channel and the second path of frequency conversion channel, and the first path of non-frequency conversion TDD-LTE uplink signal and the second path of frequency conversion TDD-LTE uplink signal are combined and then transmitted to the active near-end machine through the feeder line.
4. The indoor coverage system for improving uplink interference immunity of TDD-LTE as claimed in claim 3, wherein: the system also comprises a near-end monitoring module which completes the functions of inquiring, controlling and managing various parameters of the active near-end machine; and completing the receiving and transmitting communication control of the far-end active antenna; the active near-end machine state information can be transmitted to the monitoring center in a remote mode, and the monitoring center can control and set various parameters of the active near-end machine.
5. The indoor coverage system for improving uplink interference immunity of TDD-LTE as claimed in claim 4, wherein: the system also comprises a far-end monitoring module which completes the functions of inquiring, controlling and managing various parameters of the far-end active antenna and realizes the transceiving communication with the near-end monitoring module of the active near-end machine through the transmission of the indoor signal distribution system.
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