EP1413005A1 - Variable radiation pattern communication base station - Google PatentsVariable radiation pattern communication base station
- Publication number
- EP1413005A1 EP1413005A1 EP20020774864 EP02774864A EP1413005A1 EP 1413005 A1 EP1413005 A1 EP 1413005A1 EP 20020774864 EP20020774864 EP 20020774864 EP 02774864 A EP02774864 A EP 02774864A EP 1413005 A1 EP1413005 A1 EP 1413005A1
- European Patent Office
- Prior art keywords
- base station
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- 238000004891 communication Methods 0 description title 5
- 230000001702 transmitter Effects 0 claims description 2
- 230000001276 controlling effects Effects 0 claims 2
- 238000005365 production Methods 0 claims 1
- 230000000875 corresponding Effects 0 description 13
- 238000005562 fading Methods 0 description 5
- 230000000051 modifying Effects 0 description 5
- 230000000694 effects Effects 0 description 2
- 238000002513 implantation Methods 0 description 2
- 230000001603 reducing Effects 0 description 2
- 238000006722 reduction reaction Methods 0 description 2
- 238000003892 spreading Methods 0 description 2
- 230000017105 transposition Effects 0 description 2
- 239000000969 carrier Substances 0 description 1
- 230000001413 cellular Effects 0 description 1
- 238000006243 chemical reaction Methods 0 description 1
- 230000001427 coherent Effects 0 description 1
- 230000001066 destructive Effects 0 description 1
- 238000001914 filtration Methods 0 description 1
- 230000000670 limiting Effects 0 description 1
- 238000000034 methods Methods 0 description 1
- 238000006011 modification Methods 0 description 1
- 230000004048 modification Effects 0 description 1
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- 230000001105 regulatory Effects 0 description 1
- 230000004044 response Effects 0 description 1
- 238000001228 spectrum Methods 0 description 1
- 230000001360 synchronised Effects 0 description 1
- H01—BASIC ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
- H01Q21/061—Two dimensional planar arrays
- H01—BASIC 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
- H01—BASIC 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
BASE STATION A RADIO CHART
The present invention signals from the transmission object between two remote transceivers from each other. It concerns more particularly the transmission and reception of signals by a base station connected by radio to radio communication terminals.
It is known that radio communication between a base station and a terminal, which can be a mobile terminal, is subject to disruptive phenomena of radio transmission between the base station antenna and the antenna of the mobile terminal, in particular to channel fading ( "fading"), due to destructive interference between signals which follow the different propagation paths between the base station and the terminal.
The diversity of one of the characters associated with this transmission is one of the methods developed to overcome fading. And are used for diversity reception, of receiving the signal simultaneously on two antennas, transmit diversity, comprising equip the base station with multiple antennas transmitting the same signals, polarization diversity, frequency diversity (see for example the book "GSM Networks" X. Lagrange et al., published by Hermes Science Publications, 2000, page 161), etc. It is known to use antennas having adjustment of the radiation pattern devices. Such adjustments relate for example to the direction of the antenna emission or the width of the emission main lobe.
These adjustments of the radiation pattern may be mechanical, such as the orientation of an antenna arranged on an articulated support, electric-mechanical joint (cf. US Patent 6,198,458), or purely electronic, as in FR-A-2 792 116.
Most electronic beam guiding antennas are composed of several antenna elements fed individually by signals obtained by phase shift of an initial signal. The phase shift value is determined based on the antenna element to which is sent the phase shifted signal, and the transmission by the antenna direction results from the combination of phase shifted relative to each other emitted by all elements signals antenna.
Such antennas are sometimes used for focusing a radio beam to a particular terminal. In a typical embodiment, the components of a radio uplink signal sent by the terminal, captured by the different antenna elements are analyzed in terms of phase differences to estimate a spatial direction from which the uplink signal . corresponding phase shifts are then applied to the downlink signal intended for the terminal so that its emission is oriented in this direction. Such electronic beam guiding enables significant reductions in the level of interference. It is mostly used in satellite antennas. However, it was proposed to use in terrestrial systems despite its implementation complex and expensive work. An object of the present invention is to provide a new way of radio diversity in a base station.
The present invention relates to a base station comprising at least a transmission antenna composed of several radiating elements generating means of at least one signal component, transmission means for addressing to the radiating elements of the antenna transmitting radio signals generated from the signal components coming from the producing means, the transmitting means including phase adjustment means to generate phase shifts in the radio signals addressed to the radiating elements and control means for a transmitting antenna pattern by adjusting said phase shifts, characterized in that the control means comprises means for varying over time at least some of said phase shifts so as to cause systematic changes in the direction of at least an antenna emission lobe around a reference direction. The present invention therefore provides a diversity scheme based on the transmission sequence of radio signal according to the different propagation paths between the base station and the terminal, and which is applicable with a single transmit antenna. The fluctuation in the direction of a transmission lobe causes variations between propagation paths followed by successive sequences of the signal, thereby avoiding that all sequences are disrupted identically. In a preferred embodiment, the phase adjustment means and the radiation pattern control means are fully electronic kind and allow a digital adjustment of the phase shift of the signal transmitted by each radiating element. Such processing the phase shifts provides in effect of adjustment possibilities of the upper phase shifts to those systems incorporating electromechanical parts, and particularly rapid variations of said phase shifts.
Fluctuations in the direction of an antenna emission lobe generated by changes in phase shifts are determined according to a previously fixed sequence. These fluctuations may for example be adapted according to the topography of the geographical area covered by the antenna, a particular emphasis emission sectors by which signal transmission is particularly effective.
In a preferred implementation, the control means are arranged to vary the phase shifts so as to vary the direction of an antenna lobe emission by discrete jumps, for example between two selected directions of hand side of a reference direction. These
_fluçtuations_peuvent result from the execution of a program. dedicated to this purpose, Order these fluctuations in the form of iterative sequences, or using a random method. The program may also include certain parameters adapted by the operator of the base station.
Preferably, the systematic changes in the direction of a transmission lobe is independent of the destination terminal of the signal components. The fluctuation in the direction of a transmission lobe is applied around a reference direction attached to that lobe. The base station may further comprise means for orienting the reference direction to at least one destination terminal at least one signal component. Optionally, when the destination terminal is mobile and that its movement is detected by the base station based on radio signals transmitted by the terminal, the transmission lobe of the reference direction may vary from façun and followed the ueμiacemeπi the mobile terminai . The fluctuation in the direction of the transmission lobe is then superimposed on the change in the reference direction of the same lobe. In general, fluctuations imposed on the direction of the transmission lobe is much faster than the change in the reference direction of the lobe. The same diversity applies to the reception by the base station radio signals transmitted by the remote mobile terminals. During reception of the signal is changed at least a direction of a reception lobe, to receive a complete radio signal in the form of signal sequences which have followed different propagation paths between the terminal and the base station.
In general, the transmit antenna of a base station is also used for reception of signals by this station. Similarly, a portion of signal processing devices associated with the antenna is common to transmission and reception. It is therefore understood, as part of the present invention that the mechanisms described concerning the issuance of a signal with diversity obtained by fluctuating at least one antenna emitting direction can be applied by simple transposition, the reception signals with a diversity corresponding to the fluctuation of at least one antenna receiving direction. In addition, some components used to vary a direction of emission, in particular the phase adjustment means and the radiation pattern control means can also be used when receiving. In a preferred mode of operation, fluctuations in or receiving directions reproduce a priori fluctuations or emission directions. However, the capacity of reception signal processing algorithms to modify or change at will the features of fluctuations of reception directions so as to make them differ if necessary characteristics of fluctuations in emission directions. The invention therefore also relates to a base station comprising at least one receiving antenna consisting of several antenna elements, the phase matching means for applying respective phase shifts of the signal components from the antenna elements, means a coπiroie α αiagramme ae ae reception antenna by adjustment of said phase shifts, and means for processing at least one signal constructed after combining the phase shifted signal components, characterized in that the control means comprises means for vary over time said phase shifts so as to cause systematic changes in the direction of at least one antenna receiving lobe around a reference direction.
Other features and advantages of the present invention will become apparent in the following description of embodiments and non-limiting implementation, with reference to the accompanying drawings in which: - Figure 1 shows a spherical coordinate system characterizing a direction of transmission or the receiving antenna of a base station;
- Figure 2 illustrates a first embodiment of the device used to control the fluctuations of the antenna emission direction;
- Figure 3 illustrates a first embodiment of the device used to control the fluctuations of the antenna receiving direction;
- Figure 4 illustrates a second embodiment of the device used to control the fluctuations of the antenna emission direction; and
- Figure 5 illustrates a second embodiment of the device used to control the fluctuations of the antenna receiving direction. In Figure 1, the base station 100 transmits via the antenna 1 a radio signal to terminals 200 within range of the antenna. The antenna 1 is formed of 2 juxtaposed radiating elements. All of these radiating elements 2 are fixed relative to the support of the antenna 101, and facing toward the geographical area to be serviced by the antenna.
The emission of the antenna pattern generally consists of a main lobe, corresponding to an angular sector within which the radiation power is greater than a set value, and limited according to the distance with respect to the antenna by the power reduction due to the propagation of the radiation. The axis of this main lobe is the direction D of the antenna emission direction D 1. The emission can be identified by a spherical coordinate system having the center the center O of the antenna 1. These coordinates include, for example the angle of elevation of the direction D of emission relative to a horizontal plane containing the point O, and the azimuth angle between the projection of the direction D on a horizontal plane and an axis R reference contained in this plane, for instance perpendicular to the array of radiating elements and passing through the point O.
Usually, a site radio transceiver comprises a cellular type base station which radiates signals in different radio separate α emission and reception ae sectors, each sector being served by a directional antenna of the above type.
Fluctuations in the direction D of emission of the antenna 1 are then marked by changes of the angles of elevation and azimuth. Thus, a fluctuation in the direction D within a vertical plane corresponds to a variation of the angle of elevation. A fluctuation range in a horizontal plane corresponds to a variation of the azimuth angle.
In a typical embodiment of the invention, the fluctuation of the direction
D emission carried out collectively for all terminals independent of their location, focuses on the elevation angle. However, it is also possible to vary to the azimuth angle, or a combination of these two angles.
In most digital radio communication systems, signals are output after applying a channel coding and interleaving. Channel coding adds redundancy to the symbols of the digital signal, with a structure enabling the receiver to detect and correct transmission errors. The usually used codes have optimal performance when the errors occurring during the transmission are uncorrelated. Interlacing is a permutation of symbols intended to move towards this condition decorrelation while the transmission errors on a radio interface tend to occur in packets because of the fading phenomenon. The permutation interleaving addresses some time (a few tens of milliseconds) chosen to achieve a compromise between performance and decoder processing delay involved interleaver. This interleaving duration can vary from one channel to another, such as in the case of UMTS ( "Universal Mobile Telecommunication System") which is 10 to 80 ms. To optimize the effectiveness of the diversity created by changes in the emission direction of the antenna 1, it is advantageous that those changes are made according to a frequency of the order of, and preferably greater than the reciprocal of the interleaving period. Thus, in the case of a UMTS system, the frequency variation is preferably equal to or greater than 100 Hz. 2 schematically shows a first embodiment of the means employed by a base station to generate the diversity of the fluctuation emission direction of the antenna 1. Each signal component Si, S 2, ..., SM, for a particular terminal 200 or belonging to a common channel, is produced by a processing channel comprising a channel encoder 3, an interleaver 4, a modulator 5, then a power adjustment module 6. the signal components Si, S 2, ..., SM issued by different processing channels are then combined by a multiplexing unit 7 in a baseband signal S supplied to the radio transmission stage. The constitution of the modulators 5 and the multiplexing unit 7 depends on the employed multiple access mode in the radio communication system to which the invention is applied. In a system where multiple access is time division (TDMA) such as GSM, the modulators 5 realize the modulation baseband or an intermediate frequency, while the multiplexer 7 distributes the signal components Si, S 2, ..., SM in respective time slots of the signal frames, to corresponαant αirrerents channels. In a system where multiple access is code division (CDMA), such as UMTS, modulators 5 may perform the spectrum spreading using the spreading codes assigned to the different channels, while the multiplexer 7 simply performs a summation of signal components Si, S 2 SM. In the radio section, a separator 8 shows the S signal on each transmission channel corresponding to a radiating element 2 of the antenna 1. The phase shift unit 9 then applied to the signal of each transmission channel a respective phase shift D1, D2 DN. Each phase is determined by the position in the antenna 1 of the radiating element 2, and depends on the antenna emission direction 1 controlled by the transmission pattern controller 10. FR-A-2792116 describes an example of usable phase matching device as a unit of phase shift 9.
The radio stage then performs the conventional filtering operations, analog conversion 11, transposition of the carrier frequency 12 and power amplifier 13 from signals output from the phase shift unit 9. Each radiating element 2 receives then the amplifier 13 which is associated, via a duplexer 14, the phase-shifted radio signal E 1, E 2, ..., E corresponding to the transmission channel.
The phase shift of unit 9 may also perform a weighting of the amplitude signal corresponding to each transmission channel. In a manner known specialist radio transmissions, such a weighting to change a width of the radiation pattern by adjusting the amplitudes of the signals transmitted by each radiating element 2. Thus, during the emission of the signal by the antenna 1, the angular aperture of the emission pattern can be changed simultaneously with the fluctuation of the emission direction D in order to increase the efficiency of the creation of diversity according to the invention.
3 shows, similarly to Figure 2, an example of suitable means for the creation of diversity by fluctuation of the antenna receiving direction upon receipt of radio signals by a base station. The receiving antenna 1 composed of the antenna elements 2, receives radio signals transmitted by mobile terminals 200. Each radio signal component E'-i, E 2, ..., received by a E'N antenna element 2 is addressed to the reception channel associated with that antenna element. This pathway includes, downstream of the duplexer 14 and filter elements not shown, an amplifier with low noise 13a, a transposer frequency 12a and an analog to digital converter 11a which outputs the signal component to the phase shift unit 9a .
This phase shift unit 9a makes a compensation of the phase shifts between the signal components of each reception path so as to synchronize to the input of the combination unit 8a. This compensation of the phase shifts is regulated by the controller 10 depending on the antenna or the receiving directions 1. -
then The combining unit 8a includes one eh signal S 'the signal components from all of the reception channels and provides the S signal to the demultiplexer 7a. The latter separates the signal S 'the -Contributions S r S' 2, ... S corresponding to transmitters 200 different terminals, and the address respectively to different processing channels. Each of these channels then comprises a demodulator 5a and all the usual components necessary to extract the useful information of the received signal.
In a preferred embodiment of the invention, the fluctuation in time of the one or more transmission and / or the antenna 1 receiving directions is performed by discrete jumps, preferably between two predefined directions. This minimizes the disturbance caused in the estimation of the propagation channel process when the receiver performs a coherent demodulation. However, the tracking abilities of movement of a mobile terminal 200, with respect to changes in the impulse response, can make a continuous fluctuation mode of sinusoidal, triangular, or otherwise, also desirable for the fluctuation of the least one direction of emission and / or the receiving antenna 1. Figure 4 shows schematically a second embodiment of the means of a base station to generate diversity by fluctuation of the transmission direction. The common reference to Figure 2 correspond to identical means. In this embodiment, each antenna element α ^ receives, by means of transmission to which it is connected, a radio signal Ei, E 2, ..., IN to issue each resulting from several signals S 1, ..., S κ baseband.
Each of S 1 S κ signals is itself a combination of several signal components. Thus S \, ..., S 1 M are the components of the signal S 1, ..., and S κ ι S K M are the components of S κ signal produced by many independent processing channels. Each processing channel leads to a multiplexer 7, which produces the signal S 1, ..., S κ by combining the components. Each processing path comprises the same components as those shown with reference to Figure 2. The signal components S 1 S ι 1 M, ..., κ ι S .... S K M associated with each of the signals S 1 S κ may be, for example, multimedia .signaux of the terminal for a given recipient of one of the signals S 1, ..., S κ. They may also correspond to signals assigned to a given area served by the antenna. At the output of each multiplexer 7, the signal S 1, ..., S κ is reproduced by a separator 8 to form signal contributions associated with each transmit channel. A phase shift unit 9 then applies a phase shift to each signal contribution. For example, the phase shift D 1 ι is applied to the end signal contribution of the signal Si associated with the first transmission channel Ei radio signal and, similarly, the phase difference D N is applied to the signal contribution after the S κ signal associated with the radio signal E N ιeme transmission channel. Thus, the radio signal from an antenna 2 determined element, for example Ei, is the superposition of several elementary radio signals corresponding to contributions from each of the signals S 1, ..., S independent κ. In particular, the respective phase shifts ι D 1, ..., D κ ι applied by the phase shifting units 9 to these contributions can be different from each other, corresponding to different emitting directions of movements controlled by the controller General 10.
The assignment of each contribution of phase-shifted signal with the corresponding transmit path is performed by a valve 7 '. The valve 7 'has an entry for each contribution of phase-shifted signal, and an output connected to each transmission channel. It thus addresses each transmission channel the signal contributions of phase in accordance with the position in the antenna 1 of two antenna element powered by the transmission channel. In this second embodiment, the phase shifts are introduced upstream from the radio stage, which allows an easier implantation of the phase shift units 9, in particular an implantation of these units at the foot of the antenna 1 in the case where the radio stage is largely performed at the antenna level. Figure 5 corresponds to Figure 4 for a reception operation using the diversity resulting from the fluctuation of the antenna receiving direction.
2 each antenna element outputs a radio signal E'i, E '2 E'N one-way radio reception to which it is connected. A duplexer 14, an amplifier with low noise 13a, 12a upconverter and an analog-digital converter 11a arranged in the radio reception channel produce a signal component delivered to a distributor 7'a. By identification of channel references are included in the signal components, the distributor transmits 7'a respectively to phase shift units 9a various elementary components of each signal component corresponding to references of distinct channels. By comparing the basic components between them at the inputs of phase shift units 9a, the controller 10 then determines the phase shift applied to each control and the corresponding 9a phase shift unit to compensate for this phase shift. Elementary signal components at the output of a given phase shift unit are then synchronized. They are then combined together by a combination 8a unit to obtain a different signal S '1, ..., S p by phase shift unit 9a. Each of these signals S '1, ..., S' κ is then processed independently in the manner already described with reference to Figure 3. It is in particular separated by a demultiplexer 7a elementary signals S'ι 1 .. ., S'κ P corresponding respectively to αistincts processing channels.
An embodiment according to FIGS 4 and 5 is well suited to the case of guide antennae beams to mobile terminals. In this case, a multiplexing unit 7 may be allocated to each terminal continued for multiplexing the different channels to this terminal (the multiplexing unit is not necessary in the case where only one channel is intended for the terminal). The reference direction is then defined for each terminal by means known to those skilled in the art. The invention makes it possible to superimpose the relatively slow variation of this reference direction, due to movement of the terminal, a systematic fluctuations, faster, the emission direction around the reference direction, which helps to fight against the effects negative channel fading.
The embodiments illustrated in Figures 2 to 5 are only illustrations of two implementations of the invention. A third setting -œuvre ~ consists in printing a fluctuation in the angle of elevation to the overall emission of the antenna diagram. This fluctuation is introduced in analog or digital manner at the control of the elevation angle of the antennas. This third implementation is therefore particularly simple, since it requires no modification of the structure or the operation of currently existing antennas. In another implementation still possible, the base station generates one radio signal to the cell, in which the phase shifts are applied by means of analog phase shifters located between the duplexer and the antenna elements and controlled to vary in conjunction directions transmission and reception.
Priority Applications (3)
|Application Number||Priority Date||Filing Date||Title|
|FR0110187A FR2828031B1 (en)||2001-07-30||2001-07-30||radio base station variable radiation pattern|
|PCT/FR2002/002741 WO2003012917A1 (en)||2001-07-30||2002-07-30||Variable radiation pattern communication base station|
|Publication Number||Publication Date|
|EP1413005A1 true EP1413005A1 (en)||2004-04-28|
Family Applications (1)
|Application Number||Title||Priority Date||Filing Date|
|EP20020774864 Withdrawn EP1413005A1 (en)||2001-07-30||2002-07-30||Variable radiation pattern communication base station|
Country Status (4)
|US (1)||US7327702B2 (en)|
|EP (1)||EP1413005A1 (en)|
|FR (1)||FR2828031B1 (en)|
|WO (1)||WO2003012917A1 (en)|
Families Citing this family (3)
|Publication number||Priority date||Publication date||Assignee||Title|
|US9473187B2 (en) *||2012-12-20||2016-10-18||Cellco Partnership||Wireless radio extension using up- and down-conversion|
|US10447337B2 (en) *||2014-07-31||2019-10-15||Telefonaktiebolaget Lm Ericsson (Publ)||Duplexer system and associated digital correction for improved isolation|
|US9972893B2 (en)||2015-12-29||2018-05-15||Commscope Technologies Llc||Duplexed phased array antennas|
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|US5848103A (en) *||1995-10-04||1998-12-08||Lucent Technologies Inc.||Method and apparatus for providing time diversity|
|JP3432697B2 (en) *||1997-04-02||2003-08-04||松下電器産業株式会社||Adaptive reception diversity apparatus and an adaptive transmission diversity apparatus|
|US6104935A (en) *||1997-05-05||2000-08-15||Nortel Networks Corporation||Down link beam forming architecture for heavily overlapped beam configuration|
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