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WO1993000777A1 - Procede et dispositif servant a evaluer la frequence doppler d'une station mobile - Google Patents

Procede et dispositif servant a evaluer la frequence doppler d'une station mobile Download PDF

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Publication number
WO1993000777A1
WO1993000777A1 PCT/SE1992/000430 SE9200430W WO9300777A1 WO 1993000777 A1 WO1993000777 A1 WO 1993000777A1 SE 9200430 W SE9200430 W SE 9200430W WO 9300777 A1 WO9300777 A1 WO 9300777A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
mobile station
mobile
doppler frequency
estimating
Prior art date
Application number
PCT/SE1992/000430
Other languages
English (en)
Inventor
Bengt Erik Lennart Dahlman
Olof Tomas BÄCKSTRÖM
Bengt Anders Sandell
Lars Peter WAHLSTRÖM
Original Assignee
Telefonaktiebolaget Lm Ericsson
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 Telefonaktiebolaget Lm Ericsson filed Critical Telefonaktiebolaget Lm Ericsson
Priority to JP5501437A priority Critical patent/JPH06502291A/ja
Publication of WO1993000777A1 publication Critical patent/WO1993000777A1/fr
Priority to SE9300399A priority patent/SE9300399L/xx

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S11/00—Systems for determining distance or velocity not using reflection or reradiation
    • G01S11/02—Systems for determining distance or velocity not using reflection or reradiation using radio waves
    • G01S11/10—Systems for determining distance or velocity not using reflection or reradiation using radio waves using Doppler effect
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/32—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data
    • H04W36/324—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data by mobility data, e.g. speed data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
    • H04W64/006—Locating users or terminals or network equipment for network management purposes, e.g. mobility management with additional information processing, e.g. for direction or speed determination

Definitions

  • the present invention relates generally to cellular mobile radio systems having channels for transmitting information between base stations and mobile stations. More precisely, the invention relates to a method and apparatus for estimating the doppler frequency of a mobile station.
  • a mobile station with an established connection on a radio channel shall be able to maintain the established connection when moving from one cell to another cell wherein the cells are serviced by different or the same base station. It is also highly desirable that the mobile station with an established connection on a radio channel shall be able to maintain the established connection on the radio channel shall be able to maintain the established connection when moving within the same cell and when the radio channel which is used is subject to increased interference.
  • a process by which a mobile station can maintain an established connection when moving in a cellular radio system is generally called a handoff.
  • the second mobile station If the second mobile station has requested a handoff before the first mobile station has requested a handoff, the second mobile station will be given the first available free channel even though the signal strength between the base station and the first mobile station is rapidly decreasing. As a result, the first mobile station may lose its signal entirely breaking the call before it ever receives an available channel. This problem will only increase as the size of the individual cells decrease and the capacity of the system increases.
  • the variations in a received signals phase and strength is due to the movement of the mobile station.
  • Short term variations depend upon ultipath propagation and is called short term fading, multipath fading or just fading.
  • the maximum frequency of the fading is called doppler frequency and is proportional to the velocity of the mobile station.
  • Another variation in a received signals phase and strength is long term variations due to the change in the propagation lose between the mobile station and the base station.
  • the rate of the variation also depends upon the speed of the mobile station, e.g., the doppler frequency.
  • detecting algorithms are used to detect data in a signal received from a mobile station.
  • some detecting algorithms work better for slow moving mobiles while other detecting algorithms work better for fast moving mobile stations.
  • the systems uses detecting algorithms that usually optimize a received signal from a fast moving mobile station. As a result, a non-optimum solution results for slow moving mobile stations.
  • the present invention overcomes the shortcomings of the prior art by taking into account the speed of a mobile station during a call handoff and when detecting data in a received signal.
  • the speed of a mobile station is deter ⁇ mined when the mobile station requests a handoff.
  • a handoff queue can be prioritized according to the speed of the mobile station. For example, a fast moving mobile station will be given a higher priority than a slow moving mobile station. As a result, the faster moving mobile stations, which are losing their signals faster than the slower moving mobile stations, receive the first available free channels. As a result, fewer mobile stations will lose their calls.
  • the speed of a mobile station can be used when deciding which detecting algorithm should be used for detecting data in a received signal.
  • the cellular mobile radio system can select detecting algorithms which give the best results for each individual mobile station.
  • an estimate of the doppler frequency is determined by first determining an estimate of the channel between the transmitter and the receiver.
  • the channel is considered to be a linear transfer function with an impulse response which creates all the variations in phase and signal strength between the transmitter and the receiver.
  • Several channel estimates are made at different times and the difference between the channel estimates is used to determine the approximate doppler frequency of the mobile station.
  • Figure 1 illustrates a portion of a cellular mobile radio system having cells, a mobile switching center, base stations and mobile stations.
  • Figure 2 is a block diagram of the relationship between the transmitter and the receiver.
  • Figure 3 is a block diagram of the circuit arrangement used in the method according to the present invention.
  • Figure 4 is a flow chart illustrating the calculation of the doppler frequency.
  • Figure 1 illustrates 10 cells C1-C10, in a cellular mobile radio system. Normally, a cellular mobile radio system according to the present invention would be implemented with more than 10 cells. However, for the purposes of simplicity, the present invention can be explained using the simplified representation illustrated in Figure 1.
  • Figure 1 illustrates the base stations as situated in the vicinity of the cell center and having omni directional antennas.
  • the cells C1-C10 are, therefore, schematically represented as hexagons.
  • the base stations of adjacent cells may, however, be co-located in the vicinity of the cell borders and have directional antennas as is well known to those skilled in the art.
  • Figure 1 also illustrates 9 mobile stations M1-M9 movable within a cell and from one cell to another. In a typical cellular radio system there would normally be 9 cellular mobile stations. In fact, there are typically many times the number of mobile stations as there are base stations. However, for the purposes of explaining the invention, the reduced number of mobile stations is suf- ficient.
  • 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 10 base stations B1-B10 by cables.
  • the mobile switching center MSC is also connected by cables to a fixed public switching telephone network. All cables from the mobile switching center MSC to the base stations B1-B10 and cables to the fixed network are not illustrated.
  • cables other means, for example, fixed radio links may be used for connecting base stations B1-B10 to the mobile switching center MSC.
  • the mobile switching center MSC, the base station B1-B10 and the mobile stations M1-M9 are all computer controlled.
  • FIG. 2 illustrates an overview picture of the link between a transmitter 10 and a receiver 14.
  • the transmitter 10 is in the mobile station and the receiver 14 is located at the base station.
  • Transmitter 10 sends a signal to the receiver 14 through a channel 12.
  • the channel is considered to be a linear transfer function with an impulse response h(t) which creates all the variations and phase and signal strength between the transmitter and the receiver.
  • the transmitted signal s(t) is affected by the channel impulse response h(t) to form the received signal r(t) which is fed into a channel estimator 16 which calculates a discrete approximation to h(t) called h(n) .
  • the discrete approximation h(n) is then fed into the fading frequency estimator 18 which produces an estimate of the doppler frequency for the mobile station.
  • FIG. 3 provides a detailed description of the components contained in the fading frequency estimator 18.
  • the fading frequency estimator circuit contains a delay circuit D for delaying a channel estimate for D samples.
  • An arrangement 24 is used for forming the difference between two channel estimates wherein one estimate has been delayed for D samples.
  • the result of the arrangement 24 is a signal V j (n) which is equal to the difference between two channel estimates.
  • the circuit also contains low pass filters 26, 30 and 34 which reduce the amount of noise and modulation rests in a signal.
  • the circuit also contains squaring circuits 28 and 32 which square the V j (n) signal and the h j (n) signal. In the alternative, magnitude calculators can be substituted for the squaring circuits 28 and 32 to calculate the amplitude of the signals.
  • the circuit contains a comparing component for dividing two signals.
  • the operation of the fading frequency estimator shown in Figur 3 will be described in more detail with reference to Figure 4
  • the channel estimator 16 calculates a channel estimate of th impulse response h(t) for a time tl.
  • the channel estimator the calculates a second channel estimate component at a time t2 whic occurs D samples later in Step 52.
  • the arrangement 24 the calculates the difference between the two channel estimat components h j (n) and h j (n-D) in Step 52.
  • the result of th difference between the two signals is the signal V j (n) .
  • Th signal V (n) is then filtered by a low pass filter 26 to reduce the amount of noise and modulation in the signal. This is essential to getting a useful doppler frequency estimate in a noise environment.
  • the V j (n) signal is then squared in Step 58.
  • the square value of the signal V j (n) is then passed through a low pass filter 30 in Step 60.
  • the h j (n) signal is squared in Step 62 and passed through a low pass filter 34 in Step 64.
  • the square value of the signal V j (n) is divided by the square value of the h j (n) signal to normalize the signal in Step 56.
  • the result is proportional to the squared value of the doppler frequency for the mobile station.
  • the speed of the mobile station can be estimated by determining the approximate doppler frequency for the mobile station.
  • the present invention determines an approximation of the doppler frequency of a mobile station.
  • the cellular mobile radio system can use the doppler frequency or the speed of the mobile station to prioritize a handoff queue or to select an appropriate detecting algorithm.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

Procédé et dispositif servant à évaluer la fréquence doppler d'une station mobile (M1-M9), au moyen de l'examen du signal entre la station mobile (M1-M9) et une station de base (B1-B10). On calcule plusieurs évaluations de canaux (hj(n)) à différents intervalles (t1, t2) concernant le signal entre la station mobile (M1-M9) et la station de base (B1-B10). On utilise la différence (Vj(n)) entre ces évaluations de canaux (hj(n)), afin de déterminer la fréquence doppler approximative de la station mobile (M1-M9). Un système de radio mobile peut utiliser la fréquence doppler de la station mobile (M1-M9), afin de donner la priorité à une file d'attente de transfert ou de sélectionner un algorithme de détection approprié servant à détecter les données dans un signal reçu (r(t)).
PCT/SE1992/000430 1991-06-27 1992-06-16 Procede et dispositif servant a evaluer la frequence doppler d'une station mobile WO1993000777A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP5501437A JPH06502291A (ja) 1991-06-27 1992-06-16 移動局のドプラー周波数を見積る方法及び装置
SE9300399A SE9300399L (sv) 1991-06-27 1993-02-08 Method and apparatus for estimating the doppler frequency of a mobile station

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US72187891A 1991-06-27 1991-06-27
US721,878 1991-06-27

Publications (1)

Publication Number Publication Date
WO1993000777A1 true WO1993000777A1 (fr) 1993-01-07

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1992/000430 WO1993000777A1 (fr) 1991-06-27 1992-06-16 Procede et dispositif servant a evaluer la frequence doppler d'une station mobile

Country Status (6)

Country Link
JP (1) JPH06502291A (fr)
AU (1) AU2232992A (fr)
CA (1) CA2089090A1 (fr)
GB (1) GB2262688A (fr)
MX (1) MX9203067A (fr)
WO (1) WO1993000777A1 (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2274228A (en) * 1993-01-12 1994-07-13 Nec Corp Controlling handoff in a cellular mobile radio system
WO1996013946A1 (fr) * 1994-10-31 1996-05-09 Motorola Inc. Procede et systeme de selection intelligente d'une cellule a l'aide de donnees d'emplacement dans des systemes cellulaires
US5551059A (en) * 1994-10-31 1996-08-27 Motorola, Inc. Method and system for intelligent cell selection using doppler data in cellular systems
WO1997000587A1 (fr) * 1995-06-16 1997-01-03 Nokia Telecommunications Oy Procede d'identification d'une station mobile a vitesse de deplacement elevee, et station de base associee
EP0660627A3 (fr) * 1993-12-22 1997-01-29 Nokia Mobile Phones Ltd Radio-téléphone multi-modes.
EP0669775A3 (fr) * 1994-02-25 1999-08-18 AT&T Corp. Procédé d'établissement de priorités des procédures de transferts d'appel dans un système cellulaire
EP1026518A1 (fr) * 1999-02-08 2000-08-09 Mitsubishi Electric Information Technology Centre Europe B.V. Procédé d'estimation de la vitesse de déplacement relatif d'un émetteur et d'un récepteur en communication l'un avec l'autre d'un système de télécommunications
WO2002037136A1 (fr) * 2000-10-23 2002-05-10 Linkair Communications, Inc. Procede permettant de mesurer le glissement de frequence par effet doppler et dispositif associe
US6850505B1 (en) * 1999-09-01 2005-02-01 Telefonaktiebolaget L M Ericsson (Publ) Method and apparatus for Doppler frequency estimation
US8199696B2 (en) 2001-03-29 2012-06-12 Qualcomm Incorporated Method and apparatus for power control in a wireless communication system
EP3183929A4 (fr) * 2014-08-20 2018-04-18 Telefonaktiebolaget LM Ericsson (publ) Procédé et appareil destinés à coordonner des ressources
US10320462B2 (en) 2016-06-07 2019-06-11 Telefonaktiebolaget Lm Ericsson (Publ) Doppler shift or doppler spread as input for beam-switching or node-switching in wireless networks

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2972445B2 (ja) * 1992-07-17 1999-11-08 日本電気通信システム株式会社 電界レベル測定方式
GB2370449A (en) * 2000-12-15 2002-06-26 Motorola Inc Cell selection using kinetic characteristics

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0424704A2 (fr) * 1989-10-26 1991-05-02 Vaisala Oy Méthode et dispositif pour mesurer la vitesse d'une cible utilisant le décalage Doppler de radiation électromagnétique
GB2240696A (en) * 1990-01-31 1991-08-07 Nec Corp Method of controlling handoff in cellular mobile radio communications systems
WO1992001950A2 (fr) * 1990-07-25 1992-02-06 British Telecommunications Public Limited Company Estimation de vitesse

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0424704A2 (fr) * 1989-10-26 1991-05-02 Vaisala Oy Méthode et dispositif pour mesurer la vitesse d'une cible utilisant le décalage Doppler de radiation électromagnétique
GB2240696A (en) * 1990-01-31 1991-08-07 Nec Corp Method of controlling handoff in cellular mobile radio communications systems
WO1992001950A2 (fr) * 1990-07-25 1992-02-06 British Telecommunications Public Limited Company Estimation de vitesse

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2274228B (en) * 1993-01-12 1997-03-26 Nec Corp A method of and arrangement for effectively reducing signal strength measurements for a handoff in a cellular mobile communication system
GB2274228A (en) * 1993-01-12 1994-07-13 Nec Corp Controlling handoff in a cellular mobile radio system
EP0660627A3 (fr) * 1993-12-22 1997-01-29 Nokia Mobile Phones Ltd Radio-téléphone multi-modes.
US6421538B1 (en) 1993-12-22 2002-07-16 Nokia Mobile Phones, Limited Multi-mode radio telephone with velocity sensing mode selection
EP0669775A3 (fr) * 1994-02-25 1999-08-18 AT&T Corp. Procédé d'établissement de priorités des procédures de transferts d'appel dans un système cellulaire
WO1996013946A1 (fr) * 1994-10-31 1996-05-09 Motorola Inc. Procede et systeme de selection intelligente d'une cellule a l'aide de donnees d'emplacement dans des systemes cellulaires
US5551059A (en) * 1994-10-31 1996-08-27 Motorola, Inc. Method and system for intelligent cell selection using doppler data in cellular systems
GB2308955A (en) * 1994-10-31 1997-07-09 Motorola Inc Method and system for intelligent cell selection using location data in cellular systems
CN1087130C (zh) * 1995-06-16 2002-07-03 诺基亚电信公司 用以识别快速移动站的方法以及一个基站
WO1997000587A1 (fr) * 1995-06-16 1997-01-03 Nokia Telecommunications Oy Procede d'identification d'une station mobile a vitesse de deplacement elevee, et station de base associee
AU709470B2 (en) * 1995-06-16 1999-08-26 Nokia Telecommunications Oy Method for identifying a fast speed mobile station, and a base station
US6259919B1 (en) 1995-06-16 2001-07-10 Nokia Telecommunications Oy Method for identifying a fast speed mobile station, and a base station
FR2789492A1 (fr) * 1999-02-08 2000-08-11 Mitsubishi Electric Inf Tech Procede d'estimation de la vitesse de deplacement relatif d'un emetteur et d'un recepteur en communication l'un avec l'autre d'un systeme de telecommunications
EP1026518A1 (fr) * 1999-02-08 2000-08-09 Mitsubishi Electric Information Technology Centre Europe B.V. Procédé d'estimation de la vitesse de déplacement relatif d'un émetteur et d'un récepteur en communication l'un avec l'autre d'un système de télécommunications
US6542745B1 (en) 1999-02-08 2003-04-01 Mitsubishi Denki Kabushiki Kaisha Method of estimating the speed of relative movement of a transmitter and a receiver, in communication with one another, of a telecommunication system
US6850505B1 (en) * 1999-09-01 2005-02-01 Telefonaktiebolaget L M Ericsson (Publ) Method and apparatus for Doppler frequency estimation
WO2002037136A1 (fr) * 2000-10-23 2002-05-10 Linkair Communications, Inc. Procede permettant de mesurer le glissement de frequence par effet doppler et dispositif associe
US8199696B2 (en) 2001-03-29 2012-06-12 Qualcomm Incorporated Method and apparatus for power control in a wireless communication system
EP3183929A4 (fr) * 2014-08-20 2018-04-18 Telefonaktiebolaget LM Ericsson (publ) Procédé et appareil destinés à coordonner des ressources
US10536243B2 (en) 2014-08-20 2020-01-14 Telefonaktiebolaget Lm Ericsson (Publ) Method and apparatus for coordinating resources
US11265121B2 (en) 2014-08-20 2022-03-01 Telefonaktiebolaget L M Ericsson (Publ) Method and apparatus for coordinating resources
US12058062B2 (en) 2014-08-20 2024-08-06 Telefonaktiebolaget Lm Ericsson (Publ) Method and apparatus for coordinating resources
US10320462B2 (en) 2016-06-07 2019-06-11 Telefonaktiebolaget Lm Ericsson (Publ) Doppler shift or doppler spread as input for beam-switching or node-switching in wireless networks

Also Published As

Publication number Publication date
JPH06502291A (ja) 1994-03-10
GB2262688A (en) 1993-06-23
GB9303107D0 (en) 1993-04-21
MX9203067A (es) 1992-12-01
AU2232992A (en) 1993-01-25
CA2089090A1 (fr) 1992-12-28

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