WO2004109949A1 - Method for estimation of maximum doppler frequency - Google Patents

Method for estimation of maximum doppler frequency Download PDF

Info

Publication number
WO2004109949A1
WO2004109949A1 PCT/CN2003/000438 CN0300438W WO2004109949A1 WO 2004109949 A1 WO2004109949 A1 WO 2004109949A1 CN 0300438 W CN0300438 W CN 0300438W WO 2004109949 A1 WO2004109949 A1 WO 2004109949A1
Authority
WO
WIPO (PCT)
Prior art keywords
doppler frequency
autocorrelation function
maximum doppler
spreads
composite
Prior art date
Application number
PCT/CN2003/000438
Other languages
French (fr)
Inventor
Oskar Mauritz
Original Assignee
Huawei Technologies Co., Ltd.
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 Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Priority to PCT/CN2003/000438 priority Critical patent/WO2004109949A1/en
Priority to AU2003245806A priority patent/AU2003245806A1/en
Priority to CNB038265850A priority patent/CN100373801C/en
Publication of WO2004109949A1 publication Critical patent/WO2004109949A1/en

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/01Reducing phase shift

Definitions

  • the present invention relates generally to digital radio communications and mobile communications, and in particular to estimation of maximum Doppler frequency.
  • the knowledge of the maximum Doppler frequency has many applications in digital radio communications systems such as adaptive coding, power control, modulation, antenna diversity and so on.
  • the speed of the mobile unit is an important parameter for Radio Resource Management (RRM). It is one of the parameters that give the optimal window length for signal strength averaging in handoff algorithms.
  • RRM Radio Resource Management
  • HCS hierarchical cell structure
  • the radio channel in a mobile communications system induces an additional modulation of the transmitted signal.
  • Every single path in the radio channel is characterized by a time- varying complex channel coefficient h(f).
  • the spectrum S(f) of the channel coefficient h(f) for a non line-of-sight path is usually modeled by the so-called Jakes' spectrum, given by c
  • J n is the wth-order Bessel function of the first kind defined as
  • the time-varying channel requires the channel coefficients to be adaptively estimated.
  • the estimation is improved by filtering pilot symbols through a low-pass filter with the same bandwidth as the maximum Doppler frequency and implies lower required transmit power.
  • the same filtering of pilot symbols lowers the noise floor in a multipath searcher, which implies improved dynamics of the searcher and/or larger detection probability and/or lower probability of false alarm for the multipath components.
  • the expression for f d in the last step can be derived from expressions (2) and (3).
  • test case is shown in table 1.
  • velocities may be as high as 500 km/h df c is of the order of 2GHz, giving a maximum f d 900 Hz.
  • a natural choice for T s in WCDMA is the slot period 667 ⁇ s.
  • the resulting l/(/r f Ty is about 1.6.
  • expression (4) is obviously not fulfilled.
  • a linear interpolation is made between the first two adjacent samples of the real part of the autocorrelation function that have positive and non-positive sign, respectively.
  • the first zero detection can give accurate estimates of fd up to about 400 Hz and reasonable results in the whole range of interest. As fd decreases ⁇ 0 increases and more values of the autocorrelation function need to be calculated. This leads to higher complexity.
  • first zero detection is more sensitive to noise than the curve fitting method since it relies on two values only of r/,( ⁇ ) ,whereas as the curve fitting talces L values into account.
  • first zero detection is not applicable if f d ⁇ 0.382/ LT S .
  • the curve-fitting method is useful for lower Doppler spreads.
  • the first zero detection method becomes more and more complex. Neither the curve-fitting method nor the first zero detection method can be used for estimating Doppler spreads in all kinds of situations.
  • the purpose of the present invention is to provide a maximum Doppler frequency estimation method that is useful for all kinds of situations.
  • the technical scheme for implementing the purpose of the invention is that of a hybrid method for estimating maximum Doppler frequency.
  • the method at least comprises: calculating autocorrelation functions of complex channel estimates from a received signal; detecting whether the autocorrelation function values become negative or 0 within a predefined lag threshold; if it is, estimate the maximum Doppler frequency with a method appropriate for high Doppler spreads, otherwise estimate the maximum Doppler frequency with a method appropriate for low Doppler spreads.
  • Said autocorrelation functions are composite autocorrelation functions referring as:
  • Said step of calculating composite autocorrelation functions further comprising: making N estimates [h j ( «)/ _ " ' of the complex channel for every path of P paths with sampling period T s respectively, wherein/ labels the path andj-0,1,..., P-l; calculating the real part R h (lT s ) of the composite autocorrelation function using both real and imaginary parts of the complex channel estimates (A . as :
  • R h (IT, ) a where / goes from 0 to L, L+l is the number of the autocorrelation function values to be calculated ; a is a constant .
  • Said method appropriate for high Doppler spreads is the first zero detection method, comprising: making an interpolation between the samples in the first set of adjacent samples of the real part of me composite autocorrelation function , R h (lT s ), that have positive and non-positive sign to estimate ⁇ o which is the lag of the first zero of the composite autocorrelation function;
  • Said interpolation is a linear interpolation.
  • Said method appropriate for low Doppler spreads is the curve fitting method, comprising: finding the curve fitting parameters ⁇ k as
  • Said predefined lag threshold, T is less than or equal to L.
  • any Doppler spread should be considered as either low or high.
  • the maximum Doppler frequency f d which is greater than 0.382/(7T s ) as high Doppler spread, and, regarding the maximum Doppler frequency f d which is less than 0.382/(7Ty) as low Doppler spread.
  • the invention solves the problem of estimating the maximum Doppler frequency not only for high Doppler spreads but also for low Doppler spreads.
  • the maximum Doppler frequency can be estimated more accurately over a wider range of Doppler spreads than prior art.
  • the invention avoids the complexity of the estimation of maximum Doppler frequency only with first zero detection method.
  • the accuracy of the estimation of maximum Doppler frequency is greatly improved.
  • Fig.l shows the difference between 2 nd order polynomial fit and 4 th order polynomial fit as Doppler spread increases.
  • the present invention estimates the maximum Doppler frequency according to the situations of whether the values of the real part of the autocorrelation function become negative or 0 within a predefined lag threshold.
  • the proposed method is a hybrid method that utilizes two algorithms: a method suitable for low Doppler spreads, e.g.
  • the autocorrelation function is replaced by a composite autocorrelation function, i.e., the sum of the autocorrelation functions of the channel estimates for different resolved multipaths. If only one multipath is resolved, the composite autocorrelation function reduces to the autocorrelation function.
  • the curve fitting method is modified to fit polynomials of higher degree than two to the calculated curve fitting parameters so that the accuracy of the estimation can be greatly improved. For example, using a 4 th degree polynomial, the range of f d for which the curve fitting method is adequate is more than doubled. This, in itself, is however not enough to cover the range of interest.
  • R ⁇ ,(lT s ) might be used for high Doppler spread, / also takes the value 0, in contrast to the method in document [1].
  • T a threshold such that T L. If R h (lT s ) O for any I such that , then use an estimation for high Doppler spread, e.g., the first zero detection method else use an estimation for low Doppler spread, e.g., the curve fitting method.
  • T should be chosen so that the most accurate method of the first zero detection method and the curve fitting method is used.
  • step (3) the first zero detection method is described below: a.
  • a linear interpolation e.g., using linear interpolation of R h ((l-1)T S ) and R h (lT s ), i.e. a linear interpolation is made between the first two adjacent samples of the real part of the composite autocorrelation function that have positive and non-positive sign, respectively.
  • interpolations can be others such as quadratic interpolations, cubic interpolations etc, so the first set of adjacent samples of the real part of the composite autocorrelation function that have positive and non-positive sign are needed.
  • the invention can be applied to any receiver that receives a radio signal containing a sequence of pilot symbols. It can be applied in a mobile communications system regardless the multiple access scheme.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

The invention is a method for estimating the maximum Doppler frequency, comprising: calculating autocorrelation functions of complex channel estimates from a received signal; detecting whether the values of the real part of the autocorrelation function become negative or 0 within a predefined lag threshold; if it is, estimating the maximum Doppler frequency with a method appropriate for high Doppler spreads otherwise with a method appropriate for low Doppler spreads. The invention solves the problem of the estimation of maximum Doppler frequency not only for high Doppler spreads but also for low Doppler spreads. The maximum Doppler frequency can be estimated more accurately over a wider range of Doppler spreads than prior art.

Description

METHOD FOR ESTIMATION OF MAXIMUM DOPPLER
FREQUENCY
Field of the Technology
The present invention relates generally to digital radio communications and mobile communications, and in particular to estimation of maximum Doppler frequency.
Background of the Invention
The knowledge of the maximum Doppler frequency has many applications in digital radio communications systems such as adaptive coding, power control, modulation, antenna diversity and so on. The mobile velocity v being proportional to the maximum f Doppler frequency fd through v = —c , where fc is the carrier frequency of the radio
J c wave, c is the speed of light, the estimation of the mobile velocity v is equivalent to the estimation of the maximum Doppler frequency fd. The speed of the mobile unit is an important parameter for Radio Resource Management (RRM). It is one of the parameters that give the optimal window length for signal strength averaging in handoff algorithms. In a hierarchical cell structure (HCS), according to the velocity of a mobile, a mobile with low speed should be assigned to a microcell and a mobile with high speed should be assigned to a macrocell in order to reduce the number of handoffs and the interference.
The radio channel in a mobile communications system induces an additional modulation of the transmitted signal. Every single path in the radio channel is characterized by a time- varying complex channel coefficient h(f). The spectrum S(f) of the channel coefficient h(f) for a non line-of-sight path is usually modeled by the so-called Jakes' spectrum, given by c
S(f) = \f\ < U flfd)2
0 otherwise
(1) wherein/is the frequency, C is a constant, and i is the maximum Doppler frequency, also called the Doppler spread. Corresponding to expression (1), the autocorrelation function of h(f) which is noted as r/,(τ), is rh(τ) = CJ0dτ), (2)
wherein Jn is the wth-order Bessel function of the first kind defined as
Jn (x) = — ^ej(χs[n φ-nφ)dφ . (3)
The time-varying channel requires the channel coefficients to be adaptively estimated. The estimation is improved by filtering pilot symbols through a low-pass filter with the same bandwidth as the maximum Doppler frequency and implies lower required transmit power. The same filtering of pilot symbols lowers the noise floor in a multipath searcher, which implies improved dynamics of the searcher and/or larger detection probability and/or lower probability of false alarm for the multipath components.
There are several methods for maximum Doppler frequency estimation at present. There are two methods that represent the closest prior art.
One is described in C. TepedelenliogTu and G. B. Giannakis, "A Spectral Moment
Approach to Velocity Estimation in Mobile Communications", Proc. Of Wireless Communications and Networking Conf., Chicago, IL, Sept. 23-28 2000, and "On Velocity Estimation and Correlation Properties of Narrow-Band Mobile Communication Channels", IEEE Trans. Veh. Technol., vol 50, 1039-1051, July 2001 (in the following contexts named as document [1]), and is here named curve-fitting method. In this document, a covariance-based method, which has a rapid convergence and is robust to non-uniform scattering object distributions, is presented. The maximum Doppler frequency is calculated from the parameters of a curve fitting to the covariance function of the channel. Note that since h(t) is zero-mean, the auto-covariance and the autocorrelation are equivalent. The method is shown below:
l.Make N complex-valued channel estimates,
Figure imgf000003_0001
, from the received signal, with sampling period Ts.
2. Calculate L values of the autocorrelation function of the real or imaginary part of the complex channel estimates. For instance, if the real part of the channel estimates is used: N-l-L rΛ(/ = — l— ∑Rfi{Λ(« + /)}Re{/.(»)}, 1 = 1,2,...L.
3. Find the curve fitting parameters άk = argminfl, ^ rA (/ s ) - _ aklk
4. Obtain rll (0) = ά0; r;ι'(0) = 2ά2/T wherein r*(0) is the real part of the autocorrelation function value at zero, and r,"(0) is the second derivative of fh(lTs) at zero .
5. Estimate the maximum Doppler frequency as fd
Figure imgf000004_0001
The expression for fd in the last step can be derived from expressions (2) and (3).
The autocorrelation value for =0 is omitted since its expectation value includes additive noise. The method in document [1] was designed for narrow-band mobile communication channels where
LTs«\lfd. (4)
The test case is shown in table 1. In the narrow-band mobile communication systems, 2 =41.6μs with a carrier frequency fc of 900 MHz and a mobile velocity v=T00 km/h, giving/^ 83 Hz and l/(ftTs) 290. In the third generation communications systems, velocities may be as high as 500 km/h dfc is of the order of 2GHz, giving a maximum fd 900 Hz. A natural choice for Ts in WCDMA is the slot period 667μs. The resulting l/(/rfTy is about 1.6. As a consequence, expression (4) is obviously not fulfilled.
Table 1
Figure imgf000004_0002
Furthermore, simulation results show that the method in document [1] has a good performance only for a small range offd. So the method in document [1] is not fit for the third generation communications systems. Therefore there is a need for a method that can estimate the Doppler frequency over a wide range of frequencies.
Another method is disclosed in US patent 0172307 (in the following contexts named as document [2]), and is here named first zero detection. The first zero detection is based on finding the first zero, τ0, of the autocorrelation function. Since r/z(τ) is proportional to
Jo(2π/rfτ) , the first zero of r/,(τ), τ0, is given by
2.40 , . , . .. , 0.382 τ0 « — — , which implies fd « .
A linear interpolation is made between the first two adjacent samples of the real part of the autocorrelation function that have positive and non-positive sign, respectively. The first zero detection can give accurate estimates of fd up to about 400 Hz and reasonable results in the whole range of interest. As fd decreases τ0 increases and more values of the autocorrelation function need to be calculated. This leads to higher complexity.
Furthermore the first zero detection is more sensitive to noise than the curve fitting method since it relies on two values only of r/,(τ) ,whereas as the curve fitting talces L values into account. When autocorrelation values for τ up to LTS are calculated, first zero detection is not applicable if fd < 0.382/ LTS .
To sum up, the curve-fitting method is useful for lower Doppler spreads. As τ0 increases, the first zero detection method becomes more and more complex. Neither the curve-fitting method nor the first zero detection method can be used for estimating Doppler spreads in all kinds of situations.
Summary of the invention
The purpose of the present invention is to provide a maximum Doppler frequency estimation method that is useful for all kinds of situations.
The technical scheme for implementing the purpose of the invention is that of a hybrid method for estimating maximum Doppler frequency. The method at least comprises: calculating autocorrelation functions of complex channel estimates from a received signal; detecting whether the autocorrelation function values become negative or 0 within a predefined lag threshold; if it is, estimate the maximum Doppler frequency with a method appropriate for high Doppler spreads, otherwise estimate the maximum Doppler frequency with a method appropriate for low Doppler spreads. Said autocorrelation functions are composite autocorrelation functions referring as:
P-\ N-l-L .
∑ ∑ hj (n + I)h ' (n), wherein j labels the path and 1=0,1,..., L; {*,(«) j""1 is N j=ύ Λ=0 samples estimates of the complex channel for every path of P paths and * is the conjugate operator.
Said step of calculating composite autocorrelation functions further comprising: making N estimates [hj («)/ _"' of the complex channel for every path of P paths with sampling period Ts respectively, wherein/ labels the path andj-0,1,..., P-l; calculating the real part Rh(lTs) of the composite autocorrelation function using both real and imaginary parts of the complex channel estimates (A .
Figure imgf000006_0001
as :
Rh (IT, ) = a
Figure imgf000006_0002
where / goes from 0 to L, L+l is the number of the autocorrelation function values to be calculated ; a is a constant .
Said method appropriate for high Doppler spreads is the first zero detection method, comprising: making an interpolation between the samples in the first set of adjacent samples of the real part of me composite autocorrelation function , Rh(lTs), that have positive and non-positive sign to estimate τo which is the lag of the first zero of the composite autocorrelation function;
0.382 estimating the maximum Doppler frequency^ as fd = T
Said interpolation is a linear interpolation.
Said method appropriate for low Doppler spreads is the curve fitting method, comprising: finding the curve fitting parameters άk as
άk = argminni ζ Rh (lTs ) -~ΥJk aklk , where K is even and equal or greater than 0, the second sum is only over even values of k, and R/,f?7y is the real part of the composite autocorrelation function; obtaining the real part R^(0) of the composite autocorrelation function value at zero as RΛ (0) = 0 , and the second derivative R (0) of Rh(ITs) at zero as Rk"(0) = 2ά2/Ts 2 ;
1 — 27?" (( estimating the maximum Doppler frequency fd as f^ = — /
2π Rh (0)
Said predefined lag threshold, T, is less than or equal to L.
Furthermore, any Doppler spread should be considered as either low or high. Preferably, regarding the maximum Doppler frequency fd which is greater than 0.382/(7Ts) as high Doppler spread, and, regarding the maximum Doppler frequency fd which is less than 0.382/(7Ty) as low Doppler spread.
The invention solves the problem of estimating the maximum Doppler frequency not only for high Doppler spreads but also for low Doppler spreads. Through the method provided in the invention, the maximum Doppler frequency can be estimated more accurately over a wider range of Doppler spreads than prior art. Compared with prior art, the invention avoids the complexity of the estimation of maximum Doppler frequency only with first zero detection method. Furthermore, by calculating the real part of the composite autocorrelation function of the complex channel estimates for every path of P paths respectively, and by modifying the curve fitting method, the accuracy of the estimation of maximum Doppler frequency is greatly improved.
Brief Description of the Drawings Fig.l shows the difference between 2nd order polynomial fit and 4th order polynomial fit as Doppler spread increases.
Embodiments of the Invention The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The invention estimates the maximum Doppler frequency according to the situations of whether the values of the real part of the autocorrelation function become negative or 0 within a predefined lag threshold. The proposed method is a hybrid method that utilizes two algorithms: a method suitable for low Doppler spreads, e.g. a modified version of the curve fitting method described in the previous section and a method suitable for high Doppler spreads, e.g. the first zero detection method. Furthermore, the autocorrelation function is replaced by a composite autocorrelation function, i.e., the sum of the autocorrelation functions of the channel estimates for different resolved multipaths. If only one multipath is resolved, the composite autocorrelation function reduces to the autocorrelation function.
The curve fitting method is modified to fit polynomials of higher degree than two to the calculated curve fitting parameters so that the accuracy of the estimation can be greatly improved. For example, using a 4th degree polynomial, the range of fd for which the curve fitting method is adequate is more than doubled. This, in itself, is however not enough to cover the range of interest.
The detailed steps of the hybrid method are shown below: 1. Make N complex channel estimates of every path,
Figure imgf000008_0001
, j=0,\,..., PA, from the received signal, with sampling period Ts, wherein j labels the path, and P paths are considered.
2. Calculate the real part of the composite autocorrelation function using both real and imaginary parts of the complex channel estimates of step (1):
Rh (lTs) = a / = 0,1,...J,
Figure imgf000008_0002
where α can be any constant, e.g., α =1, P paths are taken into account. Here, because Rι,(lTs) might be used for high Doppler spread, / also takes the value 0, in contrast to the method in document [1]. For example, in the first zero detection method, if Rj,(lTs) is negative (/=T), then a linear interpolation between 1=0 and 1=1 can for instance be made to get an estimate of the maximum Doppler spread. Note that the value of Rh(lTs) at 1=0 is not used for low Doppler spread since that value includes noise and is of poorer quality than for other /. 3. Let 7/ be a threshold such that T L. If Rh(lTs) O for any I such that
Figure imgf000009_0001
, then use an estimation for high Doppler spread, e.g., the first zero detection method else use an estimation for low Doppler spread, e.g., the curve fitting method. Here, T should be chosen so that the most accurate method of the first zero detection method and the curve fitting method is used.
In step (3), the first zero detection method is described below: a. For the smallest value of /, 0<l T with Rh(lTs)^0 estimate the first zero, τ0 of R/, by interpolation, e.g., using linear interpolation of Rh((l-1)TS) and Rh(lTs), i.e. a linear interpolation is made between the first two adjacent samples of the real part of the composite autocorrelation function that have positive and non-positive sign, respectively.
Of course, the interpolations can be others such as quadratic interpolations, cubic interpolations etc, so the first set of adjacent samples of the real part of the composite autocorrelation function that have positive and non-positive sign are needed.
0 382 b. Estimate the maximum Doppler frequency as fd = — . τo In step (3), the curve fitting method is described below:
a. Find the curve fitting parameters ak = argminfli ^T Rh (lTs ) - ^k akl
where the second sum a,.l c is over all even numbers from 0 to K. K is not restricted to 2 as in document [1]. b. Obtain Rh (0) = ά0; R '(0) = 2ά2/Ts 2 , wherein Rh(0) is the real part of the composite autocorrelation function value at zero, and R/'(0) is the second derivative of Rι,(lTs) at zero .
c. Estimate the maximum Doppler frequency fd as fd =
Figure imgf000009_0002
f Of course, the velocity of the mobile can be estimated as v = — — c .
J c
Compared to the prior art of the curve fitting method, the parameters άk are modified to improve the accuracy of the estimation. The cause is shown as below:
When K=2 the estimation is good as long as the part of the autocorrelation function to fit to the polynomial to has a parabolic shape, which is indeed the case for the lowest maximum Doppler spreads. However, as the Doppler spread increases, the error of estimation with the curve fitting method will become larger. A higher order polynomial fit will increase the range of Doppler spreads for which the estimator has certain accuracy. See figure 1 that illustrates what happens as the Doppler spread increases (going from left to right). The dotted line is theoretical autocorrelation functions R/;(t), the dashed line is the 2nd order polynomial fit (K=2), and the solid line is the 4th order polynomial fit (K-4 . In the left graph, there is no difference between the two fits, but with the Doppler spread increasing; there is already a big difference.
The invention can be applied to any receiver that receives a radio signal containing a sequence of pilot symbols. It can be applied in a mobile communications system regardless the multiple access scheme.
While the present invention has been described with respect to particular example embodiments, those skilled in the art will recognize that the present invention is not limited to those specific embodiments described and illustrated herein.

Claims

Claims
1 Ϊ A method for estimating maximum Doppler frequency, comprising: calculating autocorrelation functions of complex channel estimates from a received signal; detecting whether the values of the real part of the autocorrelation function become negative or 0 within a predefined lag threshold T; if it is, estimate the maximum Doppler frequency with a method appropriate for high Doppler spreads, otherwise estimate the maximum Doppler frequency with a method appropriate for low Doppler spreads.
2 The method of claim 1, wherein the autocorrelation functions are composite p-\ Ή-\-L autocorrelation functions referring as: T hj (n + l)h* (n), wherein j labels the 0 «=0 path and 1=0, 1, ..., L; ψj ri)j ~ is N estimates of the complex channel for every path of P paths, and * is the conjugate operator.
3 The method of claim 2, the step of calculating composite autocorrelation functions further comprising: making N estimates ψ (")/ _"' of the complex channel for every path of P paths with sampling period Ts , respectively; calculating the real part R/,(/7 ) of the composite autocorrelation function using both real and imaginary parts of the complex channel estimates hj
Figure imgf000011_0001
as :
Figure imgf000011_0002
where goes from 0 to L, L+l is the number of the autocorrelation function values to be calculated ; a is a constant .
4 The method of claim 2 or 3, wherein the method appropriate for high Doppler spreads is the first zero detection method, comprising: making an interpolation between the samples in the first set of adjacent samples of the real part of the composite autocorrelation function, Rh(lTs) , that have positive and non-positive sign to estimate τo which is the lag of the first zero of the composite autocorrelation function;
0 382 estimating the maximum Doppler frequency^ as fd = — . τo
5 -, The method of claim 4, wherein the interpolation is a linear interpolation.
6> The method of claim 2 or 3, wherein the method appropriate for low Doppler spreads is the curve fitting method, comprising:
2 finding the curve fitting parameters άk as άk = argmina/, Rh (lTs) - aklk ,
where the second sum k aklk is over all even numbers from 0 to K, K is an even number, and Rh(lTs) is the real part of the composite autocorrelation function; obtaining the real part Rή(0) of the composite autocorrelation function value at zero as Rh (0) = ά0 , and the second derivative R (0) of RΛ( 7 at zero as Rh"(0) = 2a2/Ts 2 ;
estimating the maximum Doppler frequency f as fd =
Figure imgf000012_0001
7> The method of claim 3, wherein the predefined lag threshold T, is less than or equal to L.
8 The method of claim 3, further comprising: regarding the maximum Doppler frequency ft which is greater than 0.382/(TTs) as high Doppler spread, and, regarding the maximum Doppler frequency ft which is less than 0.382/( TTS) as low Doppler spread.
π
PCT/CN2003/000438 2003-06-05 2003-06-05 Method for estimation of maximum doppler frequency WO2004109949A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/CN2003/000438 WO2004109949A1 (en) 2003-06-05 2003-06-05 Method for estimation of maximum doppler frequency
AU2003245806A AU2003245806A1 (en) 2003-06-05 2003-06-05 Method for estimation of maximum doppler frequency
CNB038265850A CN100373801C (en) 2003-06-05 2003-06-05 Estimation method of Doppler limiting frequency

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2003/000438 WO2004109949A1 (en) 2003-06-05 2003-06-05 Method for estimation of maximum doppler frequency

Publications (1)

Publication Number Publication Date
WO2004109949A1 true WO2004109949A1 (en) 2004-12-16

Family

ID=33494594

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2003/000438 WO2004109949A1 (en) 2003-06-05 2003-06-05 Method for estimation of maximum doppler frequency

Country Status (3)

Country Link
CN (1) CN100373801C (en)
AU (1) AU2003245806A1 (en)
WO (1) WO2004109949A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130003807A1 (en) * 2010-03-11 2013-01-03 Telefonaktiebolaget L M Ericsson (Publ) Method and Apparatus for Estimating a Doppler Frequency

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11234190A (en) * 1998-02-12 1999-08-27 Oki Electric Ind Co Ltd Maximum doppler frequency observation circuit, radio channel estimation circuit and object moving speed observation circuit
CN1312625A (en) * 2001-04-29 2001-09-12 信息产业部电信传输研究所 Dynamic average length regulating method and device for channel estimation
CN1385007A (en) * 1999-08-12 2002-12-11 艾利森公司 Doppler spread estimation using channel autocorroelation function hypotheses

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6832080B1 (en) * 2000-09-12 2004-12-14 Ericsson, Inc. Apparatus for and method of adapting a radio receiver using control functions
US6922452B2 (en) * 2001-03-27 2005-07-26 Telefonaktiebolaget L M Ericsson (Publ) Method and apparatus for estimating Doppler spread

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11234190A (en) * 1998-02-12 1999-08-27 Oki Electric Ind Co Ltd Maximum doppler frequency observation circuit, radio channel estimation circuit and object moving speed observation circuit
CN1385007A (en) * 1999-08-12 2002-12-11 艾利森公司 Doppler spread estimation using channel autocorroelation function hypotheses
CN1312625A (en) * 2001-04-29 2001-09-12 信息产业部电信传输研究所 Dynamic average length regulating method and device for channel estimation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130003807A1 (en) * 2010-03-11 2013-01-03 Telefonaktiebolaget L M Ericsson (Publ) Method and Apparatus for Estimating a Doppler Frequency
US8811551B2 (en) * 2010-03-11 2014-08-19 Telefonaktiebolaget Lm Ericsson (Publ) Method and apparatus for estimating a doppler frequency

Also Published As

Publication number Publication date
CN100373801C (en) 2008-03-05
AU2003245806A1 (en) 2005-01-04
CN1788427A (en) 2006-06-14

Similar Documents

Publication Publication Date Title
US7254369B2 (en) Process and device for estimating the speed of movement of a mobile terminal of a wireless communication system
US8077627B2 (en) Receiving apparatus and method in broadband wireless access system
US8259865B2 (en) Methods and apparatus for adapting channel estimation in a communication system
EP1619846B1 (en) Method for estimating the frequency offset in a communication system over a Rayleigh fading channel
EP1767045B1 (en) Effective time-of-arrival estimation algorithm for multipath environment
US7773705B2 (en) Apparatus and method for canceling neighbor cell interference in broadband wireless communication system
US8675792B2 (en) Method of Doppler spread estimation
US8254434B2 (en) OFDM wireless mobile communication system and method for estimating SNR of channel thereof
US8149968B2 (en) Estimating a signal-to-interference ratio in a receiver of a wireless communications system
EP1210803B1 (en) Determination of data rate, based on power spectral density estimates
US20050267370A1 (en) Velocity estimation apparatus and method
EP1864400A2 (en) Doppler compensation scheme
US6249518B1 (en) TDMA single antenna co-channel interference cancellation
Gamier et al. Performance of an OFDM-SDMA based system in a time-varying multi-path channel
EP1908195A1 (en) Speed detection method in communication system, receiver, network element and processor
EP2636158A1 (en) A radio base station and a method therein for estimating a doppler spread
WO2007055469A1 (en) Method for generating preamble sequence using pn sequence, and method for time synchronization and frequency offset estimation using pn sequence
US8185073B2 (en) Noise/signal estimation for wireless systems
US9100262B2 (en) Apparatus and method for receiving data in communication system
WO2004109949A1 (en) Method for estimation of maximum doppler frequency
KR101541813B1 (en) Cinr estimation apparatus and method in a wireless communication system
US8126067B2 (en) Apparatus and method for estimating channel in communication system supporting OFDM/OFDMA
US20100008452A1 (en) Method and apparatus for estimating doppler frequency in a mobile terminal
US6014413A (en) Time-shifted weighting for signal processing
Du et al. Design of coherence-aware channel indication and prediction for rate adaptation

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SC SD SE SG SK SL TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 20038265850

Country of ref document: CN

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP