WO2009079848A1 - Procédé pour estimer un étalement de spectre de fréquence et une vitesse d'une station mobile - Google Patents

Procédé pour estimer un étalement de spectre de fréquence et une vitesse d'une station mobile Download PDF

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Publication number
WO2009079848A1
WO2009079848A1 PCT/CN2007/003715 CN2007003715W WO2009079848A1 WO 2009079848 A1 WO2009079848 A1 WO 2009079848A1 CN 2007003715 W CN2007003715 W CN 2007003715W WO 2009079848 A1 WO2009079848 A1 WO 2009079848A1
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WIPO (PCT)
Prior art keywords
value
mobile station
interval
channel estimation
state
Prior art date
Application number
PCT/CN2007/003715
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English (en)
Chinese (zh)
Inventor
Jiewei Ding
Wei Shen
Zhibao Gao
Feng Wang
Original Assignee
Zte Corporation
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.)
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Publication date
Application filed by Zte Corporation filed Critical Zte Corporation
Priority to PCT/CN2007/003715 priority Critical patent/WO2009079848A1/fr
Publication of WO2009079848A1 publication Critical patent/WO2009079848A1/fr

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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

Definitions

  • the present invention relates to the field of communications, and in particular, to a spectrum spreading and mobile station speed estimating method.
  • Background Art In mobile communication, a mobile station moves in various directions at various speeds during communication, so that the received signal produces a Doppler spectrum spreading effect in the spectrum. Generally, the faster the movement speed, the greater the frequency expansion.
  • the algorithms and parameters of the mobile communication system (such as multipath search in the wireless signal receiving algorithm, channel estimation, filtering average method, etc.) need to consider the influence of the frequency expansion effect, or adopt a set of compromised algorithms and parameters for various applications.
  • the mobile station speed scenario either by estimating the moving speed of the mobile station in real time, dynamically selecting different algorithm parameters or even different algorithms according to the speed of the mobile station.
  • the Rayleigh fading rate of the radio channel is estimated, thereby estimating the relative speed between the transmitter and the receiver.
  • the disadvantage of this method is that it is not estimated to be inaccurate and has a small scope of application.
  • the change of the inner loop power control command is not only the channel
  • the 10 methods are also affected by the interference noise. Especially when the speed of the mobile station is not too large, the phase estimation value of the channel estimation value is relatively small with time, and the influence of noise is more serious.
  • the normalization process of this method includes division operations, and there is room for improvement in the amount of calculation.
  • the disadvantage of this method lies in the pass-through filtering. On the one hand, the amount of calculation is large. On the one hand, it is theoretically impossible to filter out all the noise. The noise within the maximum frequency spread frequency of the possible frequency cannot be filtered out. Otherwise, the spectrum spread estimation method is Invalid. SUMMARY OF THE INVENTION In view of the above one or more questions, the present invention provides a kind of calculation, which is more simple and simple, and the performance can be more improved. Adding 2255 superior superiority to the frequency of language expansion and expansion estimation estimator and moving mobile platform speed estimation estimation method method. .
  • the method for estimating the frequency of the spread and the moving speed of the moving platform is included in the following steps: Step Step SS110022, Initial The initial initializer counter and the sum state state variable amount, and the cycle period property is obtained as the current latest latest channel channel estimation estimated value; step SS110044, Indeed, determining the real-estimate portion of the estimated channel estimate of the statistical metrics and/or the amplitude of the imaginary part of the estimator varies across the predetermined predetermined area. The number of times between the intervals; and in step SS 110066, the root estimates the magnitude, size, and shift of the spread spectrum spectrum spread according to the number of times determined according to the determined number of times. Speed of the platform. .
  • step b determines the threshold value, and the threshold value is used to eliminate the influence of the noise interference on the spectrum spread estimation;
  • C Obtain a channel estimation result of the currently received signal, and obtain a complex channel estimation value.
  • the wireless link corresponding to the mobile station has entered the synchronization state in the case of at least one of the following: and the frequency offset compensation function of the center frequency of the mobile station enters the steady state.
  • the threshold value can be determined by counting the average of the modulus values of the channel estimation values within a predetermined time.
  • Step S104 includes: Step a: determining whether the channel estimation value crosses the interval determined by the interval indication position variable; Step b, in the case that the channel estimation value crosses the interval determined by the interval position variable, the interval crossing the count value is increased by 1, and the channel estimation is performed.
  • the state variable of the real part and/or the imaginary part becomes another state of the first state and the second state; and step c, the statistical number of times is incremented by one.
  • the interval indicated by the interval indication position variable may be a static interval or a dynamic interval.
  • Step S106 includes: Step a, estimating the size of the frequency extension or the speed of the mobile station according to the current interval crossing count value if the statistical frequency value is equal to the predetermined number of times; and step b, the statistical frequency value and the interval crossing The number of times is set to the value at initialization.
  • the frequency speech extension estimation and the mobile station speed estimation method of the present invention solve the shortcomings of the existing spectrum extension and the mobile station speed estimation method, and the calculation is more concise and the performance is superior.
  • FIG. 1 is a flow chart of a method for estimating spectrum spread and mobile station speed according to the present invention
  • FIG. 2 is a schematic diagram of a sequence of channel estimation values according to the present invention
  • FIG. 3 is a schematic diagram of a related dynamic interval counting method
  • 4 is a schematic diagram of a related static interval counting method
  • FIG. 1 is a flow chart of a method for estimating spectrum spread and mobile station speed according to the present invention
  • FIG. 2 is a schematic diagram of a sequence of channel estimation values according to the present invention
  • FIG. 3 is a schematic diagram of a related dynamic interval counting method
  • 4 is a schematic diagram of a related static interval counting method
  • FIG. 5 is a specific flowchart of a spectrum spreading and mobile station speed estimating method according to the present invention.
  • 6 is a flow chart of a dynamic interval counting method according to the present invention;
  • FIG. 8 is a flow chart of a static interval counting method according to the present invention;
  • FIG. 8 is an estimation effect of a specific embodiment of a dynamic interval counting method according to the present invention;
  • FIG. 10 is an estimated effect of a specific embodiment of a static interval counting method according to the present invention; and
  • FIG. 11 is a cross-sectional number of times and a frequency i-ridge extension (mobile station speed) mapping relationship in a specific embodiment of the dynamic interval counting method of the present invention;
  • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.
  • the core idea of the present invention is: the number of times the amplitude of the real or imaginary part of the statistical channel estimation value changes across a certain interval, and the interval has a certain width. The magnitude of the spectrum spread and the speed of the mobile station are then indicated or estimated by this number of times.
  • the interval position is variable, it can be divided into dynamic interval counting method and static interval counting method.
  • This method can be understood as the number of times the signal amplitude crosses the interval, not the number of times a threshold is crossed.
  • the method of the present invention can be considered as an improved LCR method, or a method of SCR (Section Crossing Rate).
  • 1 is a flow chart of a method of spectrum spreading and mobile station speed estimation in accordance with the present invention. As shown in FIG. 1, the method includes: Step S102: Initialize a counter and a state variable, and periodically obtain a current latest channel estimation value.
  • Step S102 includes: Step a: Initializing a state variable of the real part and/or the imaginary part of the channel estimation value, a section crossing value of the real part and/or the imaginary part of the channel estimation value, a statistical number of times value, and an interval indicating position variable.
  • the threshold value can be determined by counting the average of the modulus values of the channel estimation values within a predetermined time. It is also possible to determine the gate P ⁇ value using the signal-to-interference ratio estimation result or the estimation result of the noise interference energy in the signal-to-interference ratio.
  • Step c Obtain a channel estimation result of the currently received signal, and obtain a complex channel estimation value h. Channel estimation is prior art and needs to be performed in almost all mobile communication systems.
  • Step S104 determining the number of times that the amplitude of the real part and/or the imaginary part of the statistical channel estimation value changes across a predetermined interval.
  • Step S104 includes: Step a: determining whether the channel estimation value crosses the interval determined by the interval indication position variable; Step b, in the case that the channel estimation value crosses the interval determined by the interval position variable, the interval crossing the count value is increased by 1, and the channel estimation is performed.
  • the state variable of the real part and/or the imaginary part becomes another state of the first state and the second state; and step c, the statistical number of times is incremented by one.
  • the interval indicated by the interval indication position variable may be a static interval or a dynamic interval. Specifically, the interval spanning count RealCnt is performed, and the state parameter RealStatus is updated. If the signal estimate crosses the currently determined interval, RealCnt is incremented by 1, and RealStatus becomes another state. If dynamic interval counting is used, an update to the interval indicating position variable RealPeakMaxMin is also required. Specifically, you can choose one of the following two methods:
  • (1) Dynamic interval counting method In the BELOW_TH state, the interval is [RealPeakMaxMin, RealPeakMaxMin+W], and in the ABOVE-TH state, the interval is [RealPeakMaxMin-W, RealPeakMaxMin].
  • Step S106 estimating the size of the spectrum spread and the mobile station speed according to the determined number of times.
  • the threshold value Th is restarted and further processing is performed.
  • the real part of the channel estimation value may be counted, and the frequency of the frequency channel extension or the mobile station speed may be estimated by the imaginary part of the statistical channel estimation value, and the estimated performance and the calculation amount are unchanged.
  • 4 bar “real” with “imaginary” 4 bar RealStatus with ImagStatus, RealCnt with ImagCnt, RealPeakMaxMin?
  • the text is ImagPeakMaxMin, real(h)?
  • the text is imag (h).
  • the initial status value of RealStatus or ImagStatus can be randomly selected ABOVE_TH or BELOW_TH, or it can be selected as follows: Determine whether the real or imaginary part of the current channel estimation value is greater than 0. If it is greater than 0, select ABOVE-TH, otherwise select BELOW_TH.
  • channel estimation values of multiple paths with stronger energy for subsequent spectrum extension estimation, and finally perform weighted averaging on the spectrum extension estimation results of the respective paths.
  • the channel estimation values of some subcarriers can be selected for spectrum spread estimation.
  • the count of RealCnt can only be increased by 1 when RealStatus goes from ABOVE TH to BELOW-TH, or only when RealStatus goes from BELOW TH to ABOVE-TH.
  • the relationship between the static interval counting method and the dynamic interval counting method is as follows: For the dynamic interval crossing counting method, if it is modified as appropriate, when the state is ABOVE-TH, Let RealPeakMaxMin be equal to Th, and when the state is BELOW_TH, let RealPeakMaxMin be equal to - Th, is equivalent to static interval counting.
  • the range of values for M and T can be determined at system design time.
  • the mapping between interval span times and spectrum spread (or mobile station speed) can also be determined by theoretical analysis, simulation, and testing during system design.
  • the frequency spread size (or mobile station speed) is a monotonically increasing function of the interval span times in a certain period of time.
  • WCDMA is taken as an example, the principle and steps of the method according to the present invention are the same. It is suitable for other mobile communication systems.
  • 2 is a schematic diagram of a sequence of channel estimation values in accordance with the present invention. Among them, the thick solid line is a real channel fading factor sequence. The channel fading factor continuously changes across the complex plane to form a curve around the origin.
  • FIG. 3 is a schematic diagram of a dynamic interval counting method according to the present invention.
  • the horizontal axis is time, in units of 1/1500 seconds, which is equivalent to one time slot in a WCDMA system.
  • the vertical axis is the imaginary part of the channel estimate.
  • the thick solid line is the imaginary part of the true channel fading factor
  • the dotted line is the imaginary part of the channel fading estimate after noise addition.
  • imag(h) is less than 0, and its state can be set to BELOW-TH, and Record PeakMaxMin as the minimum value in the BELOW state (the value is -1), the corresponding interval is [-1, -0.2], and when the 106th time slot, imag (h) is 0.8 or more larger than PeakMaxMin, then it is considered
  • the channel estimate crosses the interval once, and the J bar state value is converted to ABOVE-TH, PeakMaxMin?
  • the text records the maximum value in the ABOVE_TH state time period.
  • the time slot is 212
  • the value of point A is 0.35
  • the corresponding interval is [-0.45, 0.35]
  • the point B is smaller than point A by 0.8 or more when the time is 290.
  • the channel estimation value is considered to cross the interval once, and the state is considered.
  • the value is changed to BELOW_TH..., and this is repeated. From Figure 2, it is more than twice the number of fluctuation periods of the real channel fading factor in the 1000 slot time period, and the fluctuation frequency of the fading factor is more than 6 times in the 1000 slot time period. Directly corresponds to the frequency expansion and the speed of the mobile station.
  • the dynamic interval spanning counting method can identify that there is no zero-crossing fluctuation in the channel fluctuation process, such as the fluctuation of the last period of the real channel fading factor in FIG. 2, and the minimum value is greater than zero.
  • 4 is a schematic diagram of a static interval counting method of the present invention.
  • the vertical axis of the horizontal axis has the same meaning as in Fig. 2.
  • a state variable is set.
  • imag (h) is less than the threshold, and its state For BELOW_TH, when the 200th time slot is reached, imag(h) is greater than the threshold Th.
  • the channel estimation value is considered to cross the threshold once, and the state value is converted to ABOVE_TH, and then to 270 time slots.
  • imag ( h ) is less than the threshold -Th.
  • Step S502 Initially initialize a state variable RealStatus of the real part of the channel estimation value to
  • RealCnt and ImagCnt can also use the same counter ComCnt, because RealCnt and ImagCnt are also added when estimating the spectrum extension.
  • the timing of starting the frequency extension estimation function can be judged according to the system requirements and status, for example, determining whether the radio link corresponding to the mobile station has entered the synchronization state, the frequency offset (referring to the offset of the center frequency, not the spectrum) Expansion to both sides) Whether the compensation function enters a steady state, that is, whether the communication link is normally established, and if the normal communication state has been entered, the estimation can be started.
  • the threshold value Th is determined. The purpose of determining this threshold is to eliminate the effect of noise interference on the spectrum spread estimate.
  • Step S506 taking the channel estimation result of the current received signal to obtain a complex channel estimation value h.
  • Channel estimation is prior art and needs to be performed in almost all mobile communication systems.
  • signals of multiple paths are usually demodulated, and each path has a channel estimation result. In this case, the channel estimation value of the strongest energy path can be selected for subsequent spectrum extension estimation.
  • Step S508 performing interval crossing counting RealCnt, and updating the status parameter Real Status. If the signal estimation value crosses the currently determined interval, RealCnt is incremented by 1, and RealStatus changes to another state.
  • Step S508 is the core of the method of the present invention, and in the specific implementation, it can be further divided into a dynamic counting method and a static counting method. For the dynamic counting method, the specific process is shown in Figure 6. The completed operation can be expressed equivalently: If the current RealStatus is ABOVE_TH, then further judge:
  • RealCnt RealCnt+l
  • RealStatus BELOW TH. If RealStatus is BELOW—TH, and real(h)>Th, then:
  • M can be determined during system design, and can also be dynamically adjusted during communication.
  • the mapping between interval span times and frequency extension (or mobile station speed) can also be determined by theoretical analysis, simulation, and testing during system design.
  • the frequency extension size (or mobile station speed) is a monotonically increasing function of the interval span times. If the interval is counted for the imaginary part, ImagCnt should also be assigned 0, or 0 to the unified counter ComCnt.
  • the time interval T is waited for, and the process proceeds to step S504.
  • the time interval T can be determined at system design time. The smaller the T setting, the better the performance of the frequency extension estimation for high speed situations (such as above 250km/h), but the amount of calculation will increase accordingly.
  • the time interval T can also be dynamically updated during operation based on system requirements and recent frequency extension estimation results.
  • FIG. 8 is an estimation effect of a specific embodiment of the dynamic interval counting method of the present invention.
  • the mobile station speed V is 3, 15, 60, 120, 250, 500 km/h
  • the RF carrier center frequency is 2 GHz
  • the corresponding maximum Doppler frequency is expanded to 5.6, 27.8, 111.1, 222.2, 262.9, 925.9 Hz
  • T 0.134 ms, which is 512 chip time
  • M 3750
  • M*T 500 ms (half second).
  • the interval span count statistics are performed on both the real part and the imaginary part.
  • FIG. 10 is an estimated effect of a specific embodiment of the static interval counting method of the present invention.
  • Figure 11 is a diagram showing the relationship between interval crossing times and spectrum spreading (mobile station speed) in the specific embodiment of the static interval counting method of the present invention.
  • the parameters of the embodiment are the same as the dynamic interval counting method.
  • the method of the present invention achieves a single tube and has a good effect. It can be applied to various mobile communication systems.
  • the present invention estimates the frequency extension and the mobile station speed by using the interval spanning method based on threshold comparison and state tracking, and the implementation complexity is very low and very simple.
  • the influence of most of the interference noise in the channel estimation value can be eliminated, thereby improving the performance of the frequency estimation and the mobile station speed estimation.
  • the method of the present invention can be used in a base station of a wireless communication system or in a mobile station.
  • the above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention porte sur un procédé pour estimer un étalement de spectre de fréquence et une vitesse d'une station mobile, comprenant les opérations consistant à : initialiser un compteur et des variables d'état, et obtenir périodiquement la valeur estimée de canal courante la plus récente (S102) ; déterminer le nombre de fois que les variations d'amplitude de la partie réelle et/ou imaginaire des valeurs estimées de canal s'étalent sur une section prédéterminée (S104) ; estimer la valeur de l'étalement du spectre de fréquence et la vitesse de la station mobile selon le nombre de fois déterminé (S106).
PCT/CN2007/003715 2007-12-21 2007-12-21 Procédé pour estimer un étalement de spectre de fréquence et une vitesse d'une station mobile WO2009079848A1 (fr)

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Application Number Priority Date Filing Date Title
PCT/CN2007/003715 WO2009079848A1 (fr) 2007-12-21 2007-12-21 Procédé pour estimer un étalement de spectre de fréquence et une vitesse d'une station mobile

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Application Number Priority Date Filing Date Title
PCT/CN2007/003715 WO2009079848A1 (fr) 2007-12-21 2007-12-21 Procédé pour estimer un étalement de spectre de fréquence et une vitesse d'une station mobile

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111912597A (zh) * 2020-08-03 2020-11-10 北京环境特性研究所 模拟等离子体对目标散射频谱扩展效应的测试系统及方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1351781A (zh) * 1999-03-22 2002-05-29 艾利森公司 多普勒扩展估计系统
CN1382335A (zh) * 1999-09-01 2002-11-27 艾利森电话股份有限公司 在rake接收机中对信道改变速率的估计
CN1585511A (zh) * 2003-05-23 2005-02-23 三星电子株式会社 用电平交叉率估计速度的装置和方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1351781A (zh) * 1999-03-22 2002-05-29 艾利森公司 多普勒扩展估计系统
CN1382335A (zh) * 1999-09-01 2002-11-27 艾利森电话股份有限公司 在rake接收机中对信道改变速率的估计
CN1585511A (zh) * 2003-05-23 2005-02-23 三星电子株式会社 用电平交叉率估计速度的装置和方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111912597A (zh) * 2020-08-03 2020-11-10 北京环境特性研究所 模拟等离子体对目标散射频谱扩展效应的测试系统及方法

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