EP1178562A1 - Kalibrierung einer Gruppenantenne - Google Patents

Kalibrierung einer Gruppenantenne Download PDF

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Publication number
EP1178562A1
EP1178562A1 EP00116208A EP00116208A EP1178562A1 EP 1178562 A1 EP1178562 A1 EP 1178562A1 EP 00116208 A EP00116208 A EP 00116208A EP 00116208 A EP00116208 A EP 00116208A EP 1178562 A1 EP1178562 A1 EP 1178562A1
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EP
European Patent Office
Prior art keywords
antenna
calibrating
antenna array
correction factors
calibration
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Withdrawn
Application number
EP00116208A
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English (en)
French (fr)
Inventor
Björn Gunnar Johannisson
Ulf Forssen
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Telefonaktiebolaget LM Ericsson AB
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Telefonaktiebolaget LM Ericsson AB
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Priority to EP00116208A priority Critical patent/EP1178562A1/de
Publication of EP1178562A1 publication Critical patent/EP1178562A1/de
Withdrawn legal-status Critical Current

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    • 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 an antenna array for use in a base station in a cellular communication system. More particularly the present invention relates to a method and apparatus for calibrating an antenna array that receives and transmits communication signals without disturbing the normal traffic in the cellular communication system.
  • Figure 1 illustrates ten cells C1-C10 in a typical cellular mobile radio communication system. Normally, a cellular mobile radio system would be implemented with more than ten cells. However, for the purposes of simplicity, the present invention can be explained using the simplified representation illustrated in Figure 1. For each cell, C1-C10, there is a base station B1-B10 with the same reference number as the corresponding cell. Figure 1 illustrates the base stations as situated in the vicinity of the cell center and having omnidirectional antennas.
  • Figure 1 also illustrates nine mobile stations M1-M9 which are movable within a cell and from one cell to another.
  • the reduced number of mobile stations is sufficient.
  • a mobile switching center MSC Also illustrated in Figure 1 is a mobile switching center MSC.
  • the mobile switching center MSC illustrated in Figure 1 is connected to all ten base stations B1-B10 by cables.
  • the mobile switching center MSC is also connected by cables to a fixed switch telephone network or similar fixed network. All cables from the mobile switching center MSC to the base stations B1-B10 and cables to the fixed network are not illustrated.
  • mobile switching center MSC there may be additional mobile switching centers connected by cables to base stations other than those illustrated in Figure 1.
  • cables other means, for example, fixed radio links may also be used to connect base stations to mobile switching centers.
  • the mobile switching center MSC, the base stations and the mobile stations are all computer controlled.
  • each base station has an omnidirectional or directional antenna for broadcasting signals throughout the area covered by the base station.
  • signals for particular mobile stations are broadcast throughout the entire coverage area regardless of the relative positions of the mobile stations using the system.
  • the transmitter has one power amplifier per carrier frequency.
  • Amplified signals are combined and connected to a common antenna which has a wide azimuth beam. Due to the wide beam width of the common antenna, for example 120 or 360 degrees coverage in azimuth, the antenna gain is low and there is no spatial selectivity to use to reduce interference problems.
  • Narrow azimuth beams can be accomplished using an antenna array where each antenna section is connected to its own amplifiers.
  • One such antenna system is described in the US application with Ser.No 08/253 484, entitled “Microstrip Antenna Array", which is incorporated herein by reference.
  • the disclosed microstrip antenna array uses several beams with narrow beam width to cover the area served by the base station. As a result, the gain of the individual beams can be higher than the typical wide beam used by a traditional antenna.
  • polarization diversity can be used instead of spatial diversity to reduce fading variations and interference problems.
  • An antenna array is thus a group of similar antennas, or antenna sections, arranged in various configurations with proper amplitude and phase relations in order to give certain desired radiation characteristics.
  • the direction and shape of the narrow antenna beam are determined by weighting each column signal with appropriate phase and amplitude factors. This can for instance be implemented as analog phase shifting, digital beamforming or with a beam forming matrix such as a Butler matrix, or a combination of these features.
  • receiving and transmitting antenna arrays comprising a number of receiving and transmitting antenna sections.
  • the receiving and transmitting antenna sections comprises receiving and transmitting components that can distort the phase and the amplitude of signals.
  • these transmitting and receiving array antennas need to be accurately calibrated, so that any distortion of phase and amplitude, or time delay, of signals are corrected before transmission and after reception of the signals.
  • the antenna array comprises several antenna sections, each comprising four radiating elements. Each antenna section has an inbuilt calibration function.
  • the calibration function comprises an exciter which provides a signal for calibration and transmission, a receiver including a phase error sensing circuit referenced to the exciter and a measurement port, and a beamformer.
  • the corporate calibration network has one output for every antenna section.
  • each antenna section requires a calibration function of its own, resulting in a large amount of calibration circuits.
  • GB-2 285 537 A a method of calibrating an antenna array that receives communication signals is disclosed.
  • Each receiving antenna section is selectively disconnected from the corresponding antenna and is instead connected to a respective tapping of a loop.
  • An RF signal is fed through the loop in two different directions in turns.
  • the resulting amplitude and phase of each receiving antenna section are detected in each case.
  • the product of the signals that have traveled in different directions is constant and hence the phase and amplitude distortion in the calibration cable is corrected.
  • An disadvantage with this method is that the antennas have to be disconnected while calibrating the receivers resulting in interruption in the traffic.
  • phased array comprises transmitting and receiving phased array antennas that each includes a plurality of antenna sections.
  • Each antenna section comprises a phase adjustment network and an amplitude adjustment network.
  • a probe carrier signal is generated by a probe carrier source. By switching the probe carrier, in time sequence, between multiple antenna sections, the differential amplitude and phase characteristics of each of the antenna sections are determined. Corrective weighting coefficients are generated.
  • the calibration of an antenna array used in a cellular communication system should preferably be time efficient. Recurrent calibration while the system is running, essentially without disturbing the normal traffic in the communication system would be appreciable.
  • the present invention deals with a problem with errors occurring -in antenna arrays that might distort the phase and amplitude of received and transmitted signals. These errors affect the beam shape and the direction of the antenna beam.
  • Another problem dealt with by the present invention is how the calibration of an antenna array used in a cellular communication system can be accomplished in an easy and cost efficient way, essentially without disturbing the normal traffic in the communication system.
  • the present invention can also be used to test the antenna array to verify that the components of the array are working properly before the antenna array is used by the communication system.
  • a calibration system for calibrating an antenna array that receives communication signals according to the present invention comprises a single calibration transmitter, a calibration network and a calibration controller.
  • a calibration system for calibrating an antenna array that transmits communication signals according to the invention comprises a single calibration receiver, a calibration network and a calibration controller.
  • a method and apparatus for calibrating an antenna array that receives communication signals for use in a mobile radio communication system are disclosed.
  • a calibration signal is generated by a calibration transmitter. This signal is divided into several equal signals and injected into each antenna section of the antenna array by a calibration network. The signals pass through receiving components in each antenna section that might distort the phase and amplitude of the calibration signal. The signals that have passed the receiving components in each antenna section are measured by a calibration controller and correction factors can then be formed for each antenna section.
  • one of the receiving antenna sections is selected as a reference section and a reference correction factor is. generated for this section.
  • Correction factors, relative the reference factor, are generated for the other antenna sections.
  • the correction factors can adjust for phase and amplitude errors caused by the receiving components of each antenna section and for phase and amplitude errors caused by the used calibration network itself.
  • Each antenna section can then be adjusted using the correction factors so as to ensure that each antenna section is properly calibrated relative the other antenna sections.
  • the calibration method is performed without essentially disturbing the normal traffic.
  • the calibration signals can be injected and detected on traffic channels in use or between use at a limited time interval.
  • the calibration signals can also be low-power spread spectrum signals injected into the normal traffic flow.
  • a method and apparatus for calibrating an antenna array that transmits communication signals for use in a mobile radio communication system are disclosed.
  • Calibration signals are generated by a calibration controller and injected separately into each antenna section.
  • the antenna sections comprise transmitting components that might distort the phase and the amplitude of the signals.
  • a single calibration signal is generated by the calibration controller and injected into the different antenna sections separately in time.
  • the signal has passed the transmitting components in the respective antenna section it is collected by a calibration network and fed to a single calibration receiver.
  • a correction factor is generated for each antenna section by the calibration controller, at different times. The antenna sections are then adjusted using the correction factors so as to ensure that each section is properly calibrated.
  • a set of different orthogonal calibration signals is generated by the calibration controller and the calibration could then be performed simultaneously for all of the transmitting antenna sections.
  • An advantage with the present invention is that the performance of a radio communication system is improved by increasing the accuracy of the beam shape and direction of the antenna beam.
  • Another advantage is that an antenna array in a cellular communication system is calibrated essentially without disturbing the traffic in the communication system, in an easy and cost efficient way.
  • the present invention is primarily intended for use in base stations in cellular communication systems, although it will be understood by those skilled in the art that the present invention can also be used in other various communication applications.
  • An antenna array is typically a group of similar antennas, or antenna sections, arranged in various configurations with proper amplitude and phase relations in order to give certain desired radiation characteristics.
  • An antenna section can comprise several radiating elements. Each antenna section comprises-means for receiving or for transmitting a radio signal.
  • the antenna sections are connected to some beamforming device.
  • the beamforming can take place in a single step or in two steps. If the beamforming is performed in two steps the antenna array comprises one passive beamforming matrix, for example a Butler matrix, that handles the radio frequency signal processing, and one active beamformer that handles the rest of the signal processing concerning the formation of the beam.
  • the antenna array in the example shown in figure 2 comprises six antenna sections A1-A6, a passive beamforming matrix 201, transmitting or receiving components T/R 1 -T/R 6 , and an active beamformer 202.
  • the passive beamforming matrix is not supposed to introduce any phase or amplitude errors.
  • the signals are supposed to be distorted when passing the transmitting or receiving components.
  • the antenna array comprises six antenna sections A1-A6, transmitting or receiving components T/R 1 -T/R 6 , and an active beamformer 301.
  • a calibration network is used to calibrate the components associated with each antenna section of an antenna array.
  • Figure 4 illustrates an apparatus for calibrating an antenna array that receives communication signals in a base station configuration.
  • any time delay is considered to be small enough to -be modeled as a phase shift.
  • the calibration is performed by injecting a known calibration signal, such as a pure sinusoid, to each receiving antenna section.
  • the output from each receiving antenna section is measured when the calibration signal has passed some receiving components.
  • a calibration transmitter 401 generates a calibration signal S1, for example a pure sinusoid.
  • the calibration transmitter 401 receives control signals Sc from a calibration controller 403 that give information about when the calibration signal S1 shall be transmitted. This is indicated in figure 4 by a dashed line from the calibration controller to the calibration transmitter.
  • the calibration signal Si is fed to a calibration network 402.
  • the calibration network is a passive distribution network dividing the generated calibration signal S1 to a set of six equal signals S2, one signal for each receiving antenna section A1-A6 and these signals are applied to a calibration port at each receiving antenna section.
  • Each calibration signal S2 is then passed through receiving components R1-R6 in the respective receiving antenna sections comprising, for instance low noise amplifiers and A/Dconverters. These components might distort the phase and the amplitude of the injected signal.
  • the resulting signals y 1 (t)y 6 (t), after passing the receiving components R1-R6 in each antenna section, are collected in parallel, that is preferably simultaneously, and sampled at certain sample instants t by the calibration controller 403.
  • the calibration controller 403 comprises computation means for generating correction factors ⁇ 1 - ⁇ 6 for each receiving antenna section A1-A6 at certain times.
  • the correction factors describe the amount of corrections needed as compensation in each antenna section.
  • the correction factors can be described as amplitude and phase corrections or as corrections in in-phase and quadrature components, or shorter I- and Q-components.
  • the correction factors are applied to the traffic signals before the active beamforming.
  • the calibration controller 403 can be comprised in a beamforming device 405 as is shown in figure 4. This beamforming device is then thought of as a device that handles all signal processing including generating correction factors and adding the correction factors to the input signals before the actual beamforming.
  • the actual beamforming is performed in an active beamformer 404.
  • the beamforming can take place in two steps and in such cases a passive beamforming matrix is comprised before the input signals passes through the receiving components.
  • the antenna array comprises a passive beamforming matrix.
  • the calibration signal is then injected into each antenna section between the passive beamforming matrix and the receiving components. This is however not shown in figure 4.
  • the calibration network 402 itself might introduce phase and amplitude distortion of the calibration signals, for example due to different cable characteristics of the cables connected to different receiving antenna sections. This effect is only seen during calibration and could introduce phase and amplitude errors to the correction factors. These errors must be corrected before the correction factors are applied to the traffic signals during active traffic.
  • phase and amplitude response of the calibration network can be measured initially and be compensated for.
  • the received signal from each of the receiving antenna sections could, according to one embodiment of the invention, be related to the original transmit signal for each antenna section. This implies that the information about the transmitted signal is buffered and available during the generation of correction factors.
  • correction factors When forming the antenna beams the most interesting information is the phase and amplitude relations between the different antenna sections and not the relations between the input and the collected signals. Another way of generating correction factors, according to a preferred embodiment of the invention, is therefore to choose one of the receiving antenna sections as reference and then generate correction factors relative to the reference section.
  • the collected data can be modeled as complex samples and complex correction factors including corrections of phase and amplitude can be estimated, as will be described more in detail according to a method described below.
  • the correction of the input signals can be modeled as multiplying the input signals with complex correction factors ⁇ 1 - ⁇ 6 before the active beamforming is performed.
  • the complex correction factors can correct for both phase and amplitude. This is indicated in Figure 4 with the presence of one multiplier M1-M6 for each receiving antenna section.
  • the beamformer 404 of the antenna array then form narrow antenna beams with preferably low side lobe levels.
  • Another way to illustrate the application of the correction factors is to apply the correction of amplitude to an amplifier to change the amplitude of the signal and/or to apply the correction in phase to a phase shifter for changing the phase of the signal.
  • correction factors can be used by the beam forming device if digital beam forming is being used by adding the I- and Q-correction factors digitally.
  • a method of generating correction factors for each of the receiving antenna sections is illustrated in a flow chart in figure 5.
  • the antenna array comprises a number m of antenna sections.
  • a calibration signal for example a pure sinusoid, is generated 501.
  • This signal is divided into a separate signal for each receiving antenna section.
  • the divided signals are injected 502 into each receiving antenna section in parallel, that is preferably simultaneously.
  • the signals pass through the respective receiving antenna section and the resulting signals are separately collected 503.
  • Several samples for each antenna section are collected at different sample times t.
  • the collected signals from the M different antenna sections at a time t are stored 504 as M complex samples in a complex data vector y(t) ⁇ C M * 1 .
  • the mth component of the complex data vector is denoted y m (t) and is modeled as a complex number representing an I- and Q-sample.
  • One of the receiving antenna sections is selected 505 as a reference section.
  • the corresponding complex data element in the complex data vector is referred to as the reference data element.
  • the first data vector element y 1 (t) is selected as reference element in this example. Of course any other reference element could be chosen.
  • the correction coefficient for the reference section is determined as for instance equaling 1.
  • the relative correction factors are generated 506. There are other methods for computing the correction factors, well known to a person skilled in the art.
  • phase and amplitude of the injected signals will typically differ between different receiving antenna sections due to the phase and amplitude response of the calibration network. This phase and amplitude response is assumed to have been measured before setup.
  • the phase response of the calibration network is measured relative the reference section.
  • These compensated correction factors are then applied 508 to the received traffic signal data during normal traffic in order to calibrate the receiving antenna sections relative to each other. This could be done by multiplying the received data in each antenna section with the respective correction factor, as was previously described.
  • the amplitudes of the relative correction factors are renormalized thus generating 608 absolute correction factors.
  • the power of the calibration signal from the calibration transmitter is supposed to have been measured at the manufacturing of the calibration transmitter. Therefore the power of the calibration signal P in,1 injected into the reference antenna section is known.
  • a configuration for calibrating an antenna array that transmits communication signals in a base station is illustrated in Figure 6.
  • the antenna array comprises six transmitting antenna sections A1-A6.
  • a calibration controller 601 generates a transmit calibration signal, for example a pure sinusoid, that is applied to each transmitting antenna section A1-A6 of the antenna array.
  • the calibration signal passes through a respective transmitting antenna section comprising transmitting components T1-T6, such as power amplifiers and D/A-converters. These components might distort the phase and the amplitude of the injected signal.
  • the resulting signals y 1 (t 1 )-y 6 (t 6 ) from each transmitting antenna section are separately collected by a calibration network 602 and fed to a single calibration receiver 601.
  • the calibration network is a passive network.
  • the calibration receiver is connected to a calibration controller 603.
  • the calibration controller comprises computation means for generating correction factors ⁇ 1 - ⁇ 6 for each transmitting antenna section in dependence of the signal received from the calibration receiver 601.
  • the calibration controller 603 can be comprised in a beamforming device 605 as is shown in figure 6. This beamforming device is then thought of as a device that handles all signal processing including generating correction factors and adding the correction factors to the input signals before the actual beamforming. The actual beamforming is performed in an active beamformer 604.
  • the beamforming can take place in two steps and in such cases a passive beamforming matrix is comprised before the input signals passes through the receiving components.
  • the antenna array comprises a passive beamforming matrix.
  • the calibration signal is then collected from each antenna section between the transmitting components and the passive beamforming matrix. This is however not shown in figure 6.
  • the correction factors describe the amount of corrections needed as the compensations in each antenna section are calculated.
  • the correction factors can be described as amplitude and phase corrections or corrections in in-phase and quadrature components, or shorter I- and Q-components.
  • each transmitting antenna section has to be separately calibrated one at a time.
  • the same calibration signal is used for calibrating all transmitting antenna sections.
  • the calibration controller comprises only one signal generator. If all transmitting antenna sections were to send the same signal simultaneously the single calibration receiver would interpret the sampled data as one signal and therefore not be able to distinguish data from separate transmitting antenna sections. Hence each of the transmitting antenna sections has to be calibrated separately in time in this example.
  • the calibration signal S2(t 1 ) is first injected into a first, reference, transmitting antenna section A1 at a first time t 1 .
  • the calibration network 602 samples this transmitting antenna section when the calibration signal has passed the transmitting components T1.
  • the distorted signal y1(t 1 ) is received at a first collection time by the calibration receiver 601.
  • the same calibration signal S2(t 2 ) is injected into a second transmitting antenna section at a second time t 2 .
  • the second transmitting antenna section A2 is sampled and the phase and amplitude distorted signal y 2 (t 2 ) is received by the calibration receiver (601).
  • a compensated correction factor is generated by the calibration controller for the second transmitting antenna section relative the correction factor of the reference antenna section, according to the same method as was described in conjunction with steps 504-507 in figure 5.
  • the same calibration signal is injected into the rest of the antenna sections, one at a time, and correction factors are generated for each of the transmitting antenna sections.
  • the transmitting antenna sections preferably should be related to the limiting transmitting section, that is the antenna section that outputs the lowest power.
  • the limiting transmitting antenna section is found by finding the compensated correction factor with the largest amplitude.
  • limiting correction factors ⁇ lim, m are calculated for each transmitting antenna section as:
  • the transmitted power can be controlled so that all power amplifiers are guaranteed to work within their dynamic range.
  • the phase error that is computed according to the method described in conjunction with figure 5 then includes the real phase error and a phase error caused by the time error.
  • Time errors can occur due to several reasons, depending on the hardware implementation. If, for example one transmitting antenna section delays the sending of a signal, a constant time error could be introduced. For such a time error one might want to adjust the time base in the transmitting antenna sections. For other situations it might suffice to eliminate the phase error caused by the time error from the estimated phase error.
  • This signal has a positive and negative phase slope during the data collection interval for each transmitting antenna section.
  • One example of such a calibration signal is a signal with linear phase, with positive phase slope during a first time interval and then with the same phase slope but negative during a second consecutive time interval.
  • This could be a signal that is composed of two sinusoids with different phase slopes ⁇ + and a - different time intervals, for example: where ⁇ + ⁇ - , t 0 is the start time of the calibration signal, t b is the breakpoint between the two phase slopes, t e is the endtime of the calibration signal, f is the carrier frequency and A is the amplitude.
  • FIG 7a a graph of the phase of the calibration signal as function of time ⁇ (t) is shown for two transmitting antenna sections.
  • the first calibration signal is injected into the reference section at an initial time t 0 and a first sample is taken when the phase slope is positive, at a time t 1 .
  • a second sample is taken when the phase slope is negative at a time t 2 .
  • several samples are collected for the positive and for the negative slope. For simplicity only one sample per slope is shown in the figure.
  • the intended time between injection in two different transmitting antenna sections is a constant t c .
  • the first antenna section is then calibrated in a time slot in a first TDMA-frame and the next antenna section is calibrated in the same time slot in the following TDMA-frame.
  • the time between two consecutive corresponding injections of the calibration signal and samples should then also be t c .
  • the same calibration signal as was injected into the first transmitting antenna section should be injected into the second transmitting antenna section.
  • phase function ⁇ 2(t) of the second injected signal has the same positive ⁇ + and negative ⁇ - slope as the first injected signal in the reference section, but has a phase shift ⁇ p r in comparison to the phase response of the reference section. This is denoted as the real phase error.
  • the part of the second phase function that has a positive slope is denoted ⁇ 2 +(t) and the part with negative phase slope is denoted ⁇ 2- (t) in figure 7a.
  • a first sample of the second injected signal is taken at a time t 1 +t c and a second sample is taken at a time t 2 +t c , as is indicated in figure 7a.
  • a first sample of the second injected signal is taken at a time t 1 +t c and a second sample is taken at a time t 2 +t c , as is indicated in figure 7a.
  • several samples are collected for the positive and for the negative slope. For simplicity only one sample per slope is shown in the figure.
  • the dashed line in figure 7a illustrates the ideal situation when no time error ⁇ t exists between the transmitting antenna sections.
  • a relative, compensated phase error relating the phase error of the second antenna section to the reference antenna section can be generated according to the method described in conjunction with figure 5.
  • the phase error that will be found when estimating the phase error from the sample for the positive phase slope is denoted ⁇ p + .
  • the phase error that will be found when estimating the phase error from the sample for the negative phase slope is denoted ⁇ p - .
  • This estimated phase error will include the real phase error ⁇ p r as well as the phase error ⁇ p t introduced by the time error ⁇ t.
  • the real phase error will be used in the correction factor. If it is desirable to eliminate the time error during normal operation the time base in the transmitting antenna sections can be corrected with the time error ⁇ t.
  • the phase slope of the traffic signals may differ from the phase slope of the calibration signal. By using the formula (7.11) the time error can be calculated for every phase slope.
  • the transmitting antenna sections are capable of simultaneously transmitting different calibration signals and still perform a separate calibration for each of the transmitting antenna sections.
  • the calibration controller then generates different simultaneous signals that are mutually orthogonal.
  • orthogonal signals are signals of different frequencies or signals modulated with orthogonal codes, for example Walsh-Hadamard codes or orthogonal Gold codes.
  • the calibration controller comprises one signal generator for each of the transmitting antenna sections. This solution is therefore more hardware demanding. On the other hand it is less time consuming.
  • the orthogonal signals are simultaneously injected into a respective transmitting antenna section.
  • the resulting signals are then passed through the calibration network and received by the single calibration receiver in parallel, that is simultaneously, after having passed through the phase and amplitude distorting components of the transmitting antenna sections.
  • the collected signals are superimposed in the calibration network and received in the calibration receiver as one composite signal. Since the signal components are orthogonal, the calibration controller can separate the individual signals and compute correction coefficients of phase and amplitude.
  • the received signals from the calibration receiver have to be related to the original transmitted signals for each antenna section. This implies that the injection of a calibration signal and the sampling of the corresponding signal are synchronized. The information about the transmitted signal must be buffered and available during the generation of correction factors.
  • the calibration of the antenna array according to this invention is intended to be performed during normal traffic, such that the traffic is not affected or very little affected by the calibration.
  • the correction factors are frequency dependent. This means that correction factors for different frequencies must be generated. However, for frequencies within the same coherency bandwidth it suffices to compute one set of correction coefficients for one frequency within that band.
  • the frequency spectrum is therefore divided into a number of frequency bands, each band narrower than the coherency bandwidth. Each band is then calibrated separately.
  • the calibration could be performed on-line without disturbing the normal traffic flow in one of the following ways:
  • the method for calibration of the transmitting and receiving antenna sections of an antenna array according to the present invention could be continuously performed in the system or at specific time intervals.
  • the implementation of the on-line calibration is different for TDMA-, CDMA- and FDMA-system due to the fact that the channel concept differs in these systems.
  • a channel is defined by a time slot and a frequency.
  • the calibration of the antenna array is- performed by stealing time slots from traffic channels. Instead of handling the normal traffic signals the calibration signal is then injected and correction factors computed.
  • free time slots dedicated to traffic channels are used for calibration. This could be the time between one call terminates and the next is set up on the same slot. Calibration could then be made every time a call has terminated, which should be sufficiently often to ensure that the correction factors are reliable.
  • the calibration signal is a low-power spread spectrum signal that is injected into the normal signal flow. This signal is collected and fed to a correlation receiver comprised in the calibration controller.
  • a channel is defined by a special code.
  • a code that is already in use for a traffic channel is stolen for a short period of time and the calibration is performed.
  • a free code is used for calibration, for example between the termination of a call using a certain code and the set up of a new call using the same code.
  • a low-power spread spectrum signal is injected into the normal traffic flow.
  • This signal will have a code of its own and it will typically have lower power than the normal traffic signals. Data is collected over a longer period of time than what is needed if a normal traffic code is used.
  • a normal traffic code that is not to be used in the system is used for calibration.
  • a channel is defined by a certain frequency.
  • a short period of time is stolen from a traffic channel, for example from a frequency that is in use, and the calibration is performed.
  • free frequencies are used for a short period of time, for example the time between the termination of a call on a certain frequency and the set up of another call using that frequency.
  • a low-power spread spectrum signal is superimposed on top of a specific carrier.
  • the present invention severely reduces the accuracies required of the components connected to each antenna section because the present invention measures and corrects for errors generated by these components.
  • the system used for calibration simultaneously tests the devices associated with each antenna section so as to verify that the antenna array is working properly.
  • the invention provides a method and apparatus for calibrating the antenna sections of an antenna array comprised in a base station.
  • the calibration can be performed essentially without interrupting or disturbing the normal traffic flow in the radio communication system.
  • the calibration apparatus according to the invention only comprises one single calibration transmitter and one single calibration receiver, used to calibrate the whole receiving and transmitting antenna array.

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EP00116208A 2000-08-03 2000-08-03 Kalibrierung einer Gruppenantenne Withdrawn EP1178562A1 (de)

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Cited By (22)

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Publication number Priority date Publication date Assignee Title
WO2003009420A1 (en) * 2001-06-21 2003-01-30 Nokia Corporation Base transceiver station
EP1335450A1 (de) * 2000-10-27 2003-08-13 NEC Corporation Array-antennenempfangsvorrichtung und verfahren zu ihrer kalibration
WO2003090386A1 (en) * 2002-04-19 2003-10-30 Samsung Electronics Canada Inc. Apparatus and method for calibrating and compensating for distortion of an output signal in a smart antenna
KR20040052064A (ko) * 2002-12-13 2004-06-19 엘지전자 주식회사 어레이 안테나의 위상오차 보정장치
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TWI451704B (zh) * 2010-03-18 2014-09-01 Alcatel Lucent 用於無線電信網路之主動收發器陣列的校準
WO2016119853A1 (en) * 2015-01-29 2016-08-04 Telefonaktiebolaget Lm Ericsson (Publ) Microwave radio transmitter for compensation of phase noise and related method
WO2020043310A1 (en) * 2018-08-31 2020-03-05 Telefonaktiebolaget Lm Ericsson (Publ) Efficient antenna calibration for large antenna arrays
CN111181617A (zh) * 2019-12-31 2020-05-19 西安航天华迅科技有限公司 一种发射波束的形成方法
JPWO2021019885A1 (de) * 2019-07-31 2021-02-04
US20210063534A1 (en) * 2019-08-30 2021-03-04 Metawave Corporation Real-time calibration of a phased array antenna integrated in a beam steering radar
CN113726453A (zh) * 2021-08-31 2021-11-30 南通大学 一种应用于宽带天线阵列在时域进行校准的方法
CN113765600A (zh) * 2021-09-18 2021-12-07 上海交通大学 一种分布式阵列天线的收发参数自矫正方法
US11411624B2 (en) * 2018-09-28 2022-08-09 Telefonaktiebolaget Lm Ericsson (Publ) Systems and methods for correction of beam direction due to self-coupling
WO2022271066A1 (en) * 2021-06-23 2022-12-29 Saab Ab Time alignment of sampled radio frequency in a multi-channel receiver system
US11942694B2 (en) 2017-03-13 2024-03-26 Telefonaktiebolaget Lm Ericsson (Publ) Self-calibration of antenna array system

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EP1335450A1 (de) * 2000-10-27 2003-08-13 NEC Corporation Array-antennenempfangsvorrichtung und verfahren zu ihrer kalibration
EP1335450A4 (de) * 2000-10-27 2005-01-26 Nec Corp Array-antennenempfangsvorrichtung und verfahren zu ihrer kalibration
WO2003009420A1 (en) * 2001-06-21 2003-01-30 Nokia Corporation Base transceiver station
WO2003090386A1 (en) * 2002-04-19 2003-10-30 Samsung Electronics Canada Inc. Apparatus and method for calibrating and compensating for distortion of an output signal in a smart antenna
US7292877B2 (en) 2002-04-19 2007-11-06 Samsung Electronics Co., Ltd. Apparatus and method for calibrating and compensating for distortion of an output signal in a smart antenna
KR20040052064A (ko) * 2002-12-13 2004-06-19 엘지전자 주식회사 어레이 안테나의 위상오차 보정장치
US7106249B2 (en) * 2004-03-30 2006-09-12 Fujitsu Limited Phase calibration method and apparatus
EP1791277A1 (de) * 2005-11-28 2007-05-30 Siemens Aktiengesellschaft Verfahren und Anordnung zur Kalibrierung von Sendepfaden eines Antennensystems
WO2007060069A1 (de) * 2005-11-28 2007-05-31 Nokia Siemens Networks Gmbh & Co. Kg Verfahren und anordnung zur kalibrierung von sendepfaden eines antennensystems
US8009095B2 (en) 2008-06-20 2011-08-30 Ubidyne, Inc. Antenna array and a method for calibration thereof
GB2467772B (en) * 2009-02-13 2012-05-02 Socowave Technologies Ltd Communication system, network element and method for antenna array calibration
US8976845B2 (en) 2009-02-13 2015-03-10 Socowave Technologies, Ltd. Communication system, network element and method for antenna array calibration
WO2010092076A1 (en) * 2009-02-13 2010-08-19 Socowave Technologies Limited Communication system, network element and method for antenna array calibration
TWI451704B (zh) * 2010-03-18 2014-09-01 Alcatel Lucent 用於無線電信網路之主動收發器陣列的校準
US9113346B2 (en) 2010-03-18 2015-08-18 Alcatel Lucent Calibration
CN102870277B (zh) * 2010-03-31 2016-11-09 凯仕林-维科公司 有源天线阵列
WO2011121033A1 (en) * 2010-03-31 2011-10-06 Ubidyne, Inc. Active antenna array and method for calibration of the active antenna array
US8311166B2 (en) 2010-03-31 2012-11-13 Ubidyne, Inc. Active antenna array and method for calibration of the active antenna array
US8340612B2 (en) 2010-03-31 2012-12-25 Ubidyne, Inc. Active antenna array and method for calibration of the active antenna array
CN102870277A (zh) * 2010-03-31 2013-01-09 尤比戴尼有限公司 有源天线阵列以及用于有源天线阵列校准的方法
US8441966B2 (en) 2010-03-31 2013-05-14 Ubidyne Inc. Active antenna array and method for calibration of receive paths in said array
WO2016119853A1 (en) * 2015-01-29 2016-08-04 Telefonaktiebolaget Lm Ericsson (Publ) Microwave radio transmitter for compensation of phase noise and related method
CN107210798A (zh) * 2015-01-29 2017-09-26 瑞典爱立信有限公司 用于补偿相位噪声的微波无线电发射机及相关方法
CN107210798B (zh) * 2015-01-29 2021-01-12 瑞典爱立信有限公司 用于补偿相位噪声的微波无线电发射机及相关方法
US9654153B2 (en) 2015-01-29 2017-05-16 Telefonaktiebolaget Lm Ericsson (Publ) Microwave radio transmitters and related systems and methods
US11942694B2 (en) 2017-03-13 2024-03-26 Telefonaktiebolaget Lm Ericsson (Publ) Self-calibration of antenna array system
WO2020043310A1 (en) * 2018-08-31 2020-03-05 Telefonaktiebolaget Lm Ericsson (Publ) Efficient antenna calibration for large antenna arrays
US11757183B2 (en) 2018-08-31 2023-09-12 Telefonaktiebolaget Lm Ericsson (Publ) Efficient antenna calibration for large antenna arrays
US11411624B2 (en) * 2018-09-28 2022-08-09 Telefonaktiebolaget Lm Ericsson (Publ) Systems and methods for correction of beam direction due to self-coupling
EP4007069A4 (de) * 2019-07-31 2023-01-25 NEC Corporation Drahtloskommunikationsvorrichtung und -verfahren
JPWO2021019885A1 (de) * 2019-07-31 2021-02-04
US11990683B2 (en) 2019-07-31 2024-05-21 Nec Corporation Wireless communication device and wireless communication method
JP7497892B2 (ja) 2019-07-31 2024-06-11 日本電気株式会社 無線通信装置及び無線通信方法
US20210063534A1 (en) * 2019-08-30 2021-03-04 Metawave Corporation Real-time calibration of a phased array antenna integrated in a beam steering radar
CN111181617A (zh) * 2019-12-31 2020-05-19 西安航天华迅科技有限公司 一种发射波束的形成方法
WO2022271066A1 (en) * 2021-06-23 2022-12-29 Saab Ab Time alignment of sampled radio frequency in a multi-channel receiver system
CN113726453A (zh) * 2021-08-31 2021-11-30 南通大学 一种应用于宽带天线阵列在时域进行校准的方法
CN113726453B (zh) * 2021-08-31 2023-11-03 南通大学 一种应用于宽带天线阵列在时域进行校准的方法
CN113765600A (zh) * 2021-09-18 2021-12-07 上海交通大学 一种分布式阵列天线的收发参数自矫正方法
CN113765600B (zh) * 2021-09-18 2022-10-14 上海交通大学 一种分布式阵列天线的收发参数自矫正方法

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