Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
  • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
  • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
  • H01Q1/246—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for base stations
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
  • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
  • H01Q3/267—Phased-array testing or checking devices

Definitions

• the present invention relates to smart antenna technology of a wireless communication system, and more particularly to a method and device for calibrating a smart antenna array (column). Background of the invention
• a base station structure of a wireless communication system using a modern smart antenna includes an antenna array composed of one or more antenna elements, corresponding radio frequency feeding cables and a set of coherent radio frequency transceivers.
• the baseband processor obtains the spatial feature vector of the signal and the signal arrival direction (D0A), and then uses the corresponding algorithm to realize the receiving antenna beamforming .
• Any one of the antenna units, the corresponding RF feeder cable, and the relevant RF transceivers form a link.
• the weight of each link obtained from the uplink receive beamforming is used for the downlink transmit beamforming. Under the condition of symmetrical radio wave propagation, all the functions of the smart antenna can be realized.
• the calibration of smart antenna array is a core technology in smart antennas. Because of the characteristics of various electronic components, especially active components, in the radio frequency system that forms a smart antenna, the operating frequency, ambient temperature and use of Time and other are sensitive, and the characteristics of each link may not be the same due to the above reasons, so the calibration of the smart antenna system should be performed at any time.
• the purpose of the present invention is to design a method and a device for calibrating a smart antenna array, so as to realize real-time calibration of the smart antenna, thereby making the smart antenna system practical.
• the device of the present invention enables the method of the present invention to work effectively.
• a further object of the present invention is to provide two methods for designing and calibrating a coupling structure for calibrating a smart antenna array, so that the method of the present invention can work effectively.
• a method for calibrating a smart antenna array includes:
• reception calibration which includes: transmitting signals of a certain level on a given working carrier frequency by an analog transmitter in a beacon transceiver, and putting the N receiving links of the calibrated base station in a receiving state
• the baseband processor of the base station separately detects the output of each receiving link, and calculates the ratio of the transmission coefficient of each link during reception to that of the reference link based on the output of each receiving link; by controlling each link simulation
• the variable gain amplifier in the receiver controls the output of each receiving link, so that the ratio of the amplitude of the transmission coefficient of each link during reception to the transmission coefficient of the reference link is equal to 1;
• the phase difference ⁇ record of the link is stored in the baseband processor;
• Performing transmission calibration including: making only one link of the N transmitting links in a transmitting state at a time, while the other transmitting links are in a closed state, and the analog receiver in the beacon transceiver is giving Receive signals from each transmit link at a fixed working carrier frequency; the baseband processor of the base station processes the detected results, and calculates the transmission coefficient of each link when transmitting and the transmission coefficient of the reference link Ratio; by controlling the variable gain amplifier in the analog transmitter of each link to control the output of each transmitting link, so that the ratio of the transmission coefficient of each link when transmitting to the amplitude of the reference link transmission coefficient is equal to 1; The phase difference between each transmit link and the reference link is recorded in the baseband processor.
• the calibration of a coupling structure by using a vector network analyzer includes: setting a beacon antenna and a spatial coupling mode; the vector network analyzer connecting a feeder end of a beacon signal and an antenna unit port of a link to be calibrated, non-calibrated The antenna unit port of the link is connected to the matched load, and the transmission coefficient of the link to be calibrated is measured and recorded at the required working carrier frequency; repeat the above Step until all transmission coefficients of N links are measured and recorded.
• the calibration of the coupling structure by using the vector network analyzer further includes: setting a passive network coupling structure composed of N couplers and one 1: N passive splitter / combiner connected to the N couplers.
• N couplers are connected to the antenna ports of the N antenna units of the smart antenna array, and the output of the passive splitter / combiner is the feeder end of the beacon signal;
• the vector network analyzer is connected to the signal
• the feeder end of the target signal is connected to the antenna unit port of the link to be calibrated, and the antenna unit port of the non-calibration link is connected to a matched load, and the transmission coefficient of the link to be calibrated is measured and recorded at each required carrier frequency; repeat the above Step until all transmission coefficients of N links are measured and recorded.
• a device for calibrating a smart antenna array includes a calibrated coupling structure, a feeding cable, and a beacon transceiver; the coupling structure is coupled to N antenna elements of the smart antenna array, and the feeding cable connects the coupling structure and the beacon Transceiver, the beacon transceiver is connected to the baseband processor of the base station through a digital bus.
• the coupling structure is a beacon antenna using a spatial coupling method.
• the beacon antenna is located in a working main lobe of the radiation pattern of the N antenna units that form the smart antenna array.
• the antenna port of the beacon antenna is a feeder of the beacon signal. end.
• the beacon antenna is located at any position within the near-field or far-field area including each antenna unit.
• the coupling structure is a passive network, which includes N couplers corresponding to the N antenna elements of the smart antenna array and a 1: N passive splitter / combiner connected to the N couplers.
• the N couplers are respectively connected to the antenna ports of the N antenna units, and the output end of the passive splitter / combiner is a feeder end of a beacon signal.
• the beacon transceiver has the same structure as a radio frequency transceiver of a base station, and includes a duplexer, an analog receiver connected to the duplexer, an analog transmitter connected to the duplexer, and An analog-to-digital converter connected to an analog receiver and a digital-to-analog converter connected to an analog transmitter; the radio frequency interface of the duplexer is connected to a feeder cable of a coupling structure, the analog-to-digital converter And the digital-to-analog converter is connected to the digital bus.
• the analog receiver is provided with a variable gain amplifier for controlling gain and controlled by program software; the analog transmitter is provided with a variable gain amplifier for controlling output power and controlled by program software.
• the method and device for calibrating a smart antenna array include using a beacon transceiver and a set of coupling structures coupled with the smart antenna array.
• the coupling structure includes two technical solutions: one is to use a A method for calibrating a smart antenna system and an antenna array implementing the method using a beacon antenna that is symmetrical in geometry and located in the near-field or far-field area of the antenna.
• the beacon antenna and related calibration software are components of a wireless base station.
• the second part is to use a passive network composed of a coupler and a power divider to realize the feeding and calibration of the coupling structure to the smart antenna array.
• the method and device for calibrating a smart antenna array according to the present invention are mainly designed for a code division multiple access wireless communication system, but the proposed method and device can also be completely used for frequency division multiple access (FDMA) after simple changes. And time division multiple access (TDMA) wireless communication system for smart antenna array calibration.
• FDMA frequency division multiple access
• TDMA time division multiple access
• Fig. 1 is a schematic structural block diagram of a wireless communication base station using the method and device of the present invention.
• Fig. 2 is a schematic structural block diagram of an analog transceiver in Fig. 1.
• Figure 3 is a schematic diagram of a coupling structure using a beacon antenna
• Figure 4 is a schematic diagram of the connection structure of a coupling structure composed of a power divider and a coupler in a smart antenna array
• FIG. 5 is a schematic diagram of another coupling structure of the present invention.
• Figure 6 is a block diagram of the calibration process of the coupling structure
• FIG. 7 is a flowchart of a smart antenna calibration process according to the present invention.
• a base station structure in a typical wireless communication system such as a mobile communication system with a smart antenna or a wireless user loop system using the method and device of the present invention is shown.
• the base station structure is similar to the base station described in "Time Division Duplex Synchronous Code Division Multiple Access Wireless Communication System with Smart Antenna" (ZL 97 1 04039. 7) except for the calibration part. It mainly includes N identical antenna units 201A, 201B 201N, N nearly identical identical feeding cables 202A,
• All RF transceivers 203 are equipped with analog-to-digital converter ADC and digital-to-analog converter DAC. Therefore, the baseband input and output of all RF transceivers 203 are digital signals, and they are used with the baseband processor 204.
• a high-speed digital bus 209 is connected and uses the same local oscillator signal source 208 to ensure that each radio frequency transceiver of the base station works coherently.
• the present invention adds a calibration consisting of a coupling structure 105 (coupled radio frequency circuit), a feeding cable 206, and a beacon transceiver 207 based on the base station structure according to the different antenna arrays used.
• the feed cable 206 is used to connect the coupling structure 205 with the beacon transceiver 207, and the beacon transceiver 207 is connected to the high-speed digital bus 209, Some radio frequency transceivers 203 share the same local oscillator signal source 208.
• FIG. 2 shows the structure of the radio frequency transceiver 203 or the beacon transceiver 207 in FIG. It includes a duplexer 210, an analog receiver 211, an analog-to-digital converter 212, an analog transmitter 213, and a digital-to-analog converter 214.
• the analog receiver 211 is provided with a variable gain amplifier 215 (controllable by program software) to control its gain
• the analog transmitter 213 is provided with a variable gain amplifier 216 (controllable by program software) to control its gain.
• the radio frequency interface 217 of the duplexer 210 is directly connected to the feeding cables 202 and 206, and the analog-to-digital converter 212 and the digital-to-analog converter 214 are connected to the baseband processor 204 through a high-speed digital bus 209.
• any of the transmit-receive links is composed of antenna units (201A, 201B 201N), feeder cables (202A, 202B 202N), and The radio frequency transceivers (203A, 203B, 203N) are connected, and there is also a calibration link composed of the beacon transceiver 207 and the corresponding coupling structure (205, 206).
• the calibration of the smart antenna system is to obtain other links at a given operating carrier frequency with this reference link
• the transmission coefficient amplitude and phase difference during reception and transmission. Therefore, the calibration of the smart antenna of the present invention is the calibration of the entire system including the antenna feeder and the analog transceiver.
• i l, 2 N, respectively representing the first to N links;
• formula (2) when the point transmission is performed, the signal from the i-th link received at the receiving point A, S is the attenuation of the i-th link transmission by space propagation, and 1 is the i-th chain.
• the transmission signals br and at in both formulas are digital signals and should remain unchanged during the calibration process.
• the calibration work of the present invention is to obtain the difference between the transmission coefficients Ri, Ti of the i-th link during reception and transmission, and the transmission coefficient of the reference link through real-time measurement.
• the basic method for realizing the method of the present invention is to move the above reference point A into the antenna array by setting the beacon transceiver 207, the related feeding cable 206, and the coupling structure 205, that is, the output end of the feeding cable 206 in FIG. 1
• equations (1) and (2) will be rewritten as:
• i l, 2 N, respectively representing the first to N links;
• ACri represents the signal received by the i-th link at point C when transmitting at point C, and represents the coupling structure pair.
• BC ⁇ represents the signal received from the i-th link at the reception point C during point transmission, and it indicates that the coupling structure is the same for the i-th link. Transmission coefficient during emission testing.
• the coupling structure 205 is designed as a passive network, the coupling structure 205 will have reciprocity, that is:
• any link can be set as a reference link. If the first link is set as a reference link, the above formulas (6) and (7) are:
• i 2, 3, ... , N, denote article 2 to N links, wherein Ac ri, BCt ⁇ Ac and BCt i are measured in real time and can be pre-calibrated and It is determined by the coupling structure, so Ri / Rl and Ti / Tl required for the calibration of the smart antenna system can be simply calculated.
• a coupling structure used in the present invention is described, that is, a space coupling mode structure using a beacon antenna 230.
• the beacon antenna 230 is an antenna that is relatively fixed at the physical location to the antenna array to be calibrated.
• the beacon antenna 230 must be within the working main lobe of the radiation pattern of each antenna unit of the antenna array.
• the beacon antenna can be placed at any position, including the near field area of the antenna unit.
• the calibration method using this coupling structure is: a vector network analyzer 231 is connected to the beacon signal feeder D of the beacon antenna 230 and the antenna port Ei of the i-th calibrated link, and the other antenna ports of the calibrated antenna array are simultaneously calibrated.
• E 1 E 2 E N is connected to matching loads 232A, 232B 232N, respectively.
• the advantage of this coupling structure is simplicity, and the inconsistency of each antenna unit is considered during calibration; its disadvantage is that it is limited by the position of the beacon antenna 230.
• the beacon antenna 230 should be set in the far field region of the working range of the smart antenna array to be calibrated, which is difficult to achieve in an actual working environment. Therefore, only when an isotropic omnidirectional antenna is used as the antenna unit, a beacon antenna is set in its near field area, and its far field characteristic is used instead of its far field. Field characteristics and get their calibration. For example, when a circular antenna array is used, a beacon antenna can be placed at the center of the circular antenna array, and the reliability of the near-field test can be guaranteed by the symmetry of its geometric structure.
• the figure shows a coupling structure of a passive network 240 formed by a power divider and a coupler, and its connection with the smart antenna arrays 201A and 201B 201N.
• the coupling structure includes and
• N couplers 242A, 242B, 242N corresponding to N antennas 201 and a 1: N passive splitter / combiner 241, each coupler 242 is located in each antenna unit 201A, 201B
• the coupling structure has been independently calibrated before installation into the antenna array.
• a calibration method thereof includes: connecting a vector network analyzer 231 to a beacon signal feeder terminal D and an antenna port of an i-th calibrated link, and simultaneously calibrating the antenna
• the other antenna ports of the array such as E 2 E N , are connected to matching loads 232A and 232B 232N, respectively.
• This vector network analyzer 231 uses this vector network analyzer 231 to measure the transmission coefficient C of the i-th calibrated link and pass N tests to obtain the entire chain.
• the calibration method shown in FIG. 5 is the same as the calibration method shown in FIG. 3.
• the passive network coupling structure shown in Figure 4 is more complex than the beacon antenna coupling structure shown in Figure 3, and the inconsistencies of each antenna unit cannot be calibrated in, but it can be conveniently used for the calibration of any kind of smart antenna array. .
• FIG. 6 the calibration process of the coupling structure is shown.
• the calibration method is commonly used for the two coupling structures shown in FIG. 3 and FIG. 4.
• the coupling structure has been calibrated before the smart antenna array is put into operation, and the obtained transmission coefficient C is stored inside the base station.
• FIG. 7 the figure shows the entire calibration process of the smart antenna array, and before the smart antenna array is put into operation, its coupling structure has been calibrated according to the process shown in FIG. 6, and the obtained reception and transmission transmission coefficients C It has been saved inside the base station.
• Step 702 Receive calibration is performed first.
• Step 703 The transmitter of the beacon transceiver transmits a signal of a certain level on a given working carrier frequency to ensure that the calibrated base station receiving system works at a normal working level.
• Step 704 all transceivers in the calibrated base station receiving system are in a receiving state, that is, N links are in a receiving state;
• Step 705 the output of each receiving link is detected by the baseband processor to ensure system operation For a given receiving level and making each receiver work in a linear range, the baseband processor calculates Ri / Rl according to the output of each link receiver and uses formula (8); Steps 706, 707, according to the calculated Ri / Rl, and then by controlling the variable gain amplifiers (213, 216 in Fig.
• the reference transmitting link must be measured and calibrated in advance to ensure that its transmit power is at the rated level.
• the receiver in the beacon transceiver will Receive the signal from each transmit link separately (step 711), and the detected result is processed by the baseband processor, and is calculated using formula (9) (step 714); and then passed through each sender separately based on this value Variable gain amplifier (211, 215 in Figure 2) to control the output of each transmit link until I VT of each transmit link (step 716), and simultaneously phase each receive link with the reference link Rated ⁇ recorded in baseband Processor, a real-time calibration This completes the smart antenna.
• the method and device of the present invention are proposed for a code division multiple access wireless communication system
• the method and device can be used in a frequency division multiple access (FDMA) and time division multiple access (TDMA) wireless communication system after simple changes.
• the structure of the wireless communication base station shown in FIG. 1 is based on a time division duplex (TDD) wireless communication system as an example.
• the same structure can also be used in a frequency division duplex (FDD) wireless communication system.
• FDD frequency division duplex

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)
• Radio Transmission System (AREA)
• Details Of Aerials (AREA)
• Mobile Radio Communication Systems (AREA)

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Citations (4)

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• 1999
  • 1999-08-10 CN CN99111350A patent/CN1118146C/zh not_active Expired - Lifetime
• 2000
  • 2000-06-26 BR BRPI0013095-8A patent/BRPI0013095B1/pt not_active IP Right Cessation
  • 2000-06-26 DE DE60039988T patent/DE60039988D1/de not_active Expired - Lifetime
  • 2000-06-26 EP EP00940116A patent/EP1204161B1/en not_active Expired - Lifetime
  • 2000-06-26 WO PCT/CN2000/000178 patent/WO2001011719A1/zh not_active Ceased
  • 2000-06-26 AU AU55191/00A patent/AU777585B2/en not_active Expired
  • 2000-06-26 MX MXPA02001463A patent/MXPA02001463A/es active IP Right Grant
  • 2000-06-26 KR KR1020027001460A patent/KR100602055B1/ko not_active Expired - Lifetime
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  • 2000-06-26 RU RU2002106105/09A patent/RU2265263C2/ru active
  • 2000-06-26 JP JP2001516275A patent/JP4392476B2/ja not_active Expired - Lifetime
  • 2000-06-26 CA CA002381384A patent/CA2381384C/en not_active Expired - Lifetime
• 2002
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