WO1993020626A1 - Simulateur de l'evanouissement d'un canal radio et procede de simulation de l'evanouissement - Google Patents

Simulateur de l'evanouissement d'un canal radio et procede de simulation de l'evanouissement Download PDF

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Publication number
WO1993020626A1
WO1993020626A1 PCT/FI1993/000135 FI9300135W WO9320626A1 WO 1993020626 A1 WO1993020626 A1 WO 1993020626A1 FI 9300135 W FI9300135 W FI 9300135W WO 9320626 A1 WO9320626 A1 WO 9320626A1
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WO
WIPO (PCT)
Prior art keywords
fir
delay
fading
block
blocks
Prior art date
Application number
PCT/FI1993/000135
Other languages
English (en)
Inventor
Jussi Harju
Torsti Poutanen
Original Assignee
Elektrobit Oy
Jussi Harju
Torsti Poutanen
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Elektrobit Oy, Jussi Harju, Torsti Poutanen filed Critical Elektrobit Oy
Publication of WO1993020626A1 publication Critical patent/WO1993020626A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/391—Modelling the propagation channel
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/391—Modelling the propagation channel
    • H04B17/3911—Fading models or fading generators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/391—Modelling the propagation channel
    • H04B17/3912—Simulation models, e.g. distribution of spectral power density or received signal strength indicator [RSSI] for a given geographic region

Definitions

  • the present invention relates to a radio channel fading simulator and a method of simulating fading of a radio channel, wherein an impulse response is formed by delaying and multiplying by coefficients samples formed of an RF signal in a so-called FIR filter which varies with time.
  • Multipath propagation is a phenomenon to which radio waves are subjected when travelling in an environ ⁇ ment comprising reflecting objects (e.g. buildings, cars, trees, people, etc.). Some of the objects may be stationary, and some in motion. Because of multipath propagation, the radio signal which reaches a receiver is a linear combination of several radio signals, the phases, amplitudes and delays of which differ from one another.
  • the differences in delays are due to the fact that when the radio waves are reflected from different objects, they travel different distances in the medium. As some of the reflecting objects and even the trans ⁇ mitter or the receiver or both of them may be in motion, the relative phases, amplitudes and delays change all the time. The radio waves with different propagation paths may be combined in the receiver in such a way that they either cancel or magnify each other. Since the state of the channel varies all the time, the signal strength varies accordingly. This phenomenon is called fading.
  • a fading simulator is a device by which a fading radio channel is simulated under laboratory con ⁇ ditions. An ideal radio signal is supplied to the input of the device either in baseband form or at RF medium frequency, and a fading signal is obtained from the output.
  • Fading simulators are used in measurements of the efficiency of radio receivers.
  • Systems in which fading simulators are needed are, for example, the European digital mobile phone system GSM, the corres ⁇ ponding digital cellular phone systems in the USA and Japan, the cellular phone system DCS-1800 in England, stray spectrum systems, and military telecommunication systems.
  • the central parameters are delay spread, delay resolution, and the channel updating rate.
  • Delay spread refers to the difference in delay between those significant signal components in an impulse response of a radio channel which have the shortest and longest delay. In urban areas, for example, the delay spread is typically of the magnitude 3...5 us.
  • the requirement for high .delay spread together with accurate delay resolution leads to a technically complicated simulator when the aim is to enable simulation of any delay component from zero to maximum delay with an accuracy indicated by the delay resolution.
  • the number of the delay components needed in the simulation is the delay spread divided by the delay resolution. Each delay component is multiplied by a complex random number dependent on time. As there are many delay components, a great number of multiplica- tion calculations must be made.
  • a typical delay resolution obtainable with the existing CMOS digital technology is of the magnitude 30 ns.
  • the longest delays needed in outdoor simulations are of the magnitude 10...20 us, sometimes even longer. This implies about 300...600 delay components.
  • the existing IC circuits can realize only a few dozens of delay components.
  • the solutions that are presently available provide a high delay spread and an accurate delay resolution, but it is not possible to realize simultaneously every delay component between zero and the maximum delay with the steps indicated by the delay resolution; in practice, only part of all possible delays can be realized.
  • the delay resolution is 0.1 us and the maximum delay 200 us.
  • the number of possible delay components is merely 12.
  • a German fading simulator is also known where the delay resolution is 50 ns and the maximum delay 100 us.
  • the number of possible delay components is only 16.
  • the object of the present invention is to provide a radio channel fading simulator with superior properties compared with the prior art.
  • the radio channel fading simulator of the invention is character ⁇ ized in that the FIR filter comprises at least two FIR blocks consisting of serially coupled delay blocks, the signal samples to be delayed being conducted through each FIR block to the following FIR block, and that the filtered outputs of each FIR block are added together so as to obtain the desired total delay and resolution.
  • Figure 1 shows a typical structure of an impulse response of a radio channel
  • Figure 2 shows a block diagram of a radio channel fading simulator in a general manner
  • Figure 3 shows a FIR block of the invention in a radio channel fading simulator according to Figure 2.
  • the impulse response of a radio channel has very often a structure according to Figure 1, wherein the response is positioned in a system of coordinates, the x axis representing the delay d and the y axis the relative amplitude A.
  • the response comprises several groups a, b and c of delay components, each of said groups having its own fine structure.
  • the simulation of such a channel structure requires simultaneously an extremely good delay resolution T, the possibility of long delays, and the possibility of adjusting the delays
  • a ⁇ (t) coefficient of delay component i, a complex number dependent on time
  • T ⁇ delay of delay component i
  • N number of delay components in the model. It appears from Formula (1) that the model used is a so-called FIR filter, the tap coefficients of which vary with time.
  • An FIR filter Finite Impulse Response filter
  • K is a finite integer. The impulse response is determined on the basis of the delays and the magnitude of the coefficients mentioned above.
  • the signal and the coefficients are generally complex numbers.
  • Figure 2 shows the structure of a conventional broadband fading simulator as a block diagram.
  • An ideal modulated RF carrier wave u(t) is converted in an RF down-converter 1 to an intermediate frequency IF.
  • the intermediate frequency signal is converted to a complex baseband signal I and Q, which is converted to sample sequences of real and imaginary parts in an A/D converter block 3.
  • the sample sequence is conducted along a data bus to an FIR block 4.
  • the samples are delayed by delays T ⁇ ...T N in N delay blocks 5a, 5b, 5c, etc.
  • the delayed samples are multiplied by complex coefficients A- ⁇ (t) in multiplier blocks 6a, 6b, 6c, etc.
  • the samples are added in an adding block 7.
  • the real and imaginary parts of the samples are con ⁇ ducted as an output signal of the FIR block 4 to their own D/A converters in a D/A converter block 8.
  • the analogous I and Q signals are converted to an inter- mediate frequency in a quadrature up-converter 9.
  • the output signal of the block is a fading signal at RF medium frequency (signal s(t) in Formula (1)).
  • a con- troller 11 controls the static functional parameters of the apparatus and supplies coefficients to the multi ⁇ pliers 6. The coefficients are stored e.g. in a memory 12.
  • FIG 3 shows the structure of the FIR block of an improved fading simulator of the invention. Except for the FIR block illustrated, the structure of the fading simulator of the invention corresponds to the block diagram of Figure 2, wherefore the general description of the operation of the apparatus set forth above applies even to this case.
  • the FIR block 22 shown in Figure 3 comprises blocks 13a-13N, 14a-14N and 15, which correspond functionally to the FIR block 4 of Figure 2.
  • the complex sample sequence to the block 13a corresponds to the sample sequence to the FIR block 4 in Figure 2. If the delay resolution of the FIR block 13-15 is T (cf. Figure 2), its longest delay is N*T, in which N is the number of delay elements.
  • the samples are conducted to a delay element 16.
  • Its delay T ⁇ (cf. Figure 1) can be adjusted e.g. by means of an instruction given by the controller unit of the apparatus.
  • the delay element 16 is followed by a new FIR block 23, comprising blocks 17a-17M, 18a-18M and 19, which correspond functionally to the delay, multiplier (coefficients here B i (t) ) and adding blocks of the block 22.
  • the delay resolution of the FIR block 23 is corres ⁇ pondingly T, and its longest delay M*T. M is generally independent of N.
  • the end of the delay block chain of the FIR is provided with an extension output 21. From there, the samples can be conducted to the following FIR block (not illustrated). The number of these successive FIR blocks is arbitrary.
  • the filtered sample sequences obtained from the FIR blocks are conducted to an adder 20.
  • the complex sample sequence of its output corresponds to the sample sequence to the D/A converter block 8 in Figure 2.
  • the fading simulator of the invention shown in Figure 3 is applicable to the simulation of an impulse response according to Figure 1, since one group (a, b and c in Figure 1) of delay components can typically be simulated by one FIR group, and the delays (T ⁇ in Figure 1) between the groups can be controlled by the delay elements between the groups.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Simulateur de l'évanouissement d'un canal radio et procédé de simulation de l'évanouissement d'un canal radio. On forme une réponse impulsionnelle en retardant et en multipliant par des coefficients (Ai(t), Bi(t)) des échantillons formés d'un signal radioélectrique dans un filtre dit à réponse impulsionnelle finie (FIR) à variation dans le temps. Ledit filtre FIR comporte au moins deux blocs FIR (22, 23) constitués de blocs à retard couplés en série (13a...13N, 17a...17N), les échantillons de signal à retarder étant acheminés par l'intermédiaire d'un bloc FIR jusqu'au bloc FIR suivant. On additionne les signaux de sortie filtrés de chacun des blocs FIR (22, 23) de manière à obtenir la résolution et le retard totaux voulus.
PCT/FI1993/000135 1992-04-01 1993-03-31 Simulateur de l'evanouissement d'un canal radio et procede de simulation de l'evanouissement WO1993020626A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI921446A FI94809C (fi) 1992-04-01 1992-04-01 Radiokanavan häipymissimulaattori ja menetelmä häipymisen simuloimiseksi
FI921446 1992-04-01

Publications (1)

Publication Number Publication Date
WO1993020626A1 true WO1993020626A1 (fr) 1993-10-14

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2283392A (en) * 1993-10-29 1995-05-03 Nokia Mobile Phones Ltd RF channel simulator
DE4341201A1 (de) * 1993-12-03 1995-06-22 Gereon Schmitz Vorrichtung und Anordnung zur Simulation kontinuierlich sich ändernder Mehrwegeschwunderscheinungen mit definierten statistischen Häufigkeitsverteilungen
WO1999021305A2 (fr) * 1997-10-21 1999-04-29 Telia Ab (Publ) Simulateur de canal destine aux systemes mobiles...
WO2002067471A1 (fr) * 2001-02-21 2002-08-29 Elektrobit Oy Procede et dispositif de simulation de canal radio
WO2003047132A1 (fr) * 2001-11-27 2003-06-05 Elektrobit Oy Procede et appareil de simulation d'une voie radioelectrique
FR2853172A1 (fr) * 2003-03-27 2004-10-01 Centre Nat Etd Spatiales Emulateur de canal de propagation.
WO2004102843A1 (fr) 2003-05-15 2004-11-25 Elektrobit Testing Oy Procede et agencement de simulation de canal
WO2005008926A1 (fr) * 2003-07-17 2005-01-27 Elektrobit Testing Oy Procede et dispositif pour simuler un canal radio
US8155167B2 (en) 2006-07-21 2012-04-10 Motorola Mobility, Inc. Low complexity frequency hopping solution for performance testing system and method
ES2380459A1 (es) * 2010-08-26 2012-05-11 FUNDACIÓN CENTRO TECNOLÓXICO DE TELECOMUNICACIONS DE GALICIA (Titular al 50%) Sistema para predicción de cobertura con cosimulador hardware.
US9787414B2 (en) 2011-07-06 2017-10-10 Keysight Technologies Singapore (Holdings) Pte. Ltd. Over-the air test

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1702986B (zh) * 2005-07-15 2010-04-28 清华大学 基带多径衰落信道模拟器

Citations (6)

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Publication number Priority date Publication date Assignee Title
US3633107A (en) * 1970-06-04 1972-01-04 Bell Telephone Labor Inc Adaptive signal processor for diversity radio receivers
GB2129638A (en) * 1982-09-20 1984-05-16 Nec Corp Segmented transversal filter
US4644562A (en) * 1985-08-28 1987-02-17 At&T Company Combined cross polarization interference cancellation and intersymbol interference equalization for terrestrial digital radio systems
EP0371286A2 (fr) * 1988-12-01 1990-06-06 Rohde & Schwarz GmbH & Co. KG Procédé de génération d'un signal haute fréquence modulé par un signal d'information et distordu par un profil de fading prédéterminé pour tester des récepteurs haute fréquence et simulateur de fading pour réaliser ce procédé
US5062148A (en) * 1989-06-02 1991-10-29 Hewlett-Packard Company Multi-path fading simulator
EP0499227A2 (fr) * 1991-02-13 1992-08-19 Nec Corporation Egaliseur adaptif qui exécute une opération d'égalisation avec référence à une magnitude de fading

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3633107A (en) * 1970-06-04 1972-01-04 Bell Telephone Labor Inc Adaptive signal processor for diversity radio receivers
GB2129638A (en) * 1982-09-20 1984-05-16 Nec Corp Segmented transversal filter
US4644562A (en) * 1985-08-28 1987-02-17 At&T Company Combined cross polarization interference cancellation and intersymbol interference equalization for terrestrial digital radio systems
EP0371286A2 (fr) * 1988-12-01 1990-06-06 Rohde & Schwarz GmbH & Co. KG Procédé de génération d'un signal haute fréquence modulé par un signal d'information et distordu par un profil de fading prédéterminé pour tester des récepteurs haute fréquence et simulateur de fading pour réaliser ce procédé
US5062148A (en) * 1989-06-02 1991-10-29 Hewlett-Packard Company Multi-path fading simulator
EP0499227A2 (fr) * 1991-02-13 1992-08-19 Nec Corporation Egaliseur adaptif qui exécute une opération d'égalisation avec référence à une magnitude de fading

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2283392B (en) * 1993-10-29 1998-01-21 Nokia Mobile Phones Ltd RF channel simulator
US6058261A (en) * 1993-10-29 2000-05-02 Nokia Mobile Phones Limited RF channel simulator
GB2283392A (en) * 1993-10-29 1995-05-03 Nokia Mobile Phones Ltd RF channel simulator
DE4341201A1 (de) * 1993-12-03 1995-06-22 Gereon Schmitz Vorrichtung und Anordnung zur Simulation kontinuierlich sich ändernder Mehrwegeschwunderscheinungen mit definierten statistischen Häufigkeitsverteilungen
US6600926B1 (en) 1997-10-21 2003-07-29 Telia Ab Channel simulator for mobile systems
WO1999021305A2 (fr) * 1997-10-21 1999-04-29 Telia Ab (Publ) Simulateur de canal destine aux systemes mobiles...
WO1999021305A3 (fr) * 1997-10-21 1999-07-01 Telia Ab Simulateur de canal destine aux systemes mobiles...
USRE40986E1 (en) 1997-10-21 2009-11-17 Svante Widell Channel simulator for mobile systems
CN100514888C (zh) * 2001-02-21 2009-07-15 伊莱克特罗比特系统测试公司 仿真无线信道的方法和设备
KR100857678B1 (ko) 2001-02-21 2008-09-08 엘렉트로비트 시스템 테스트 오와이 무선 채널 시뮬레이션 방법 및 장치
WO2002067471A1 (fr) * 2001-02-21 2002-08-29 Elektrobit Oy Procede et dispositif de simulation de canal radio
US7394880B2 (en) 2001-11-27 2008-07-01 Jot Automation Oy Method and apparatus for simulating radio channel
WO2003047132A1 (fr) * 2001-11-27 2003-06-05 Elektrobit Oy Procede et appareil de simulation d'une voie radioelectrique
FR2853172A1 (fr) * 2003-03-27 2004-10-01 Centre Nat Etd Spatiales Emulateur de canal de propagation.
WO2004088885A1 (fr) * 2003-03-27 2004-10-14 Centre National D'etudes Spatiales Emulateur de canal de propagation
WO2004102843A1 (fr) 2003-05-15 2004-11-25 Elektrobit Testing Oy Procede et agencement de simulation de canal
US7852911B2 (en) 2003-05-15 2010-12-14 Elektrobit System Test Oy Method and arrangement for channel simulation
WO2005008926A1 (fr) * 2003-07-17 2005-01-27 Elektrobit Testing Oy Procede et dispositif pour simuler un canal radio
US8155167B2 (en) 2006-07-21 2012-04-10 Motorola Mobility, Inc. Low complexity frequency hopping solution for performance testing system and method
ES2380459A1 (es) * 2010-08-26 2012-05-11 FUNDACIÓN CENTRO TECNOLÓXICO DE TELECOMUNICACIONS DE GALICIA (Titular al 50%) Sistema para predicción de cobertura con cosimulador hardware.
US9787414B2 (en) 2011-07-06 2017-10-10 Keysight Technologies Singapore (Holdings) Pte. Ltd. Over-the air test

Also Published As

Publication number Publication date
FI94809C (fi) 1995-10-25
FI921446A0 (fi) 1992-04-01
FI94809B (fi) 1995-07-14
FI921446A (fi) 1993-10-02

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