CN101965047A - Method and device for detecting speed of mobile terminal - Google Patents

Abstract

The invention discloses a method and a device for detecting the speed of a mobile terminal. The method comprises the following steps of: performing noise estimation according to received network side data to obtain noise estimation values; performing channel estimation according to the received network side data and extracting a channel estimation value at a reference signal from obtained channel estimation values; determining an instantaneous maximum Doppler spread value according to the noise estimation values and the channel estimation value at the reference signal; and computing the speed of the mobile terminal according to the maximum Doppler spread value. In the method and the device, the more accurate speed of the mobile terminal can be detected in an orthogonal frequency division multiplexing (OFDM) system.

Description

A kind of detection method of portable terminal speed and device

Technical field

The present invention relates to moving communicating field, relate in particular to a kind of detection method and device of portable terminal speed.

Background technology

In mobile communication system, the speed of portable terminal is a very important parameter.By detecting? portable terminal speed can realize the comprehensive optimization of mobile communication system from the physical layer of bottom to the protocol layer of high level.For example, portable terminal speed is to realize the necessary information of multi-layer honeycomb structure, can be used as one of the allocation strategy of keriotheca and important parameter of RRM; Still solve the important evidence of portable terminal call drop problem; In addition, can also be used for the optimization of wireless receiver, as optimization of wireless receiver receptivity etc.

At present, for single-carrier system, portable terminal speed detection method commonly used has the envelope of received signal to cross zero-crossing rate (ZCR, Zero Crossing Rate) method of a grade rate (LCR, Level Corssing Rate) method and homophase, quadrature component characteristic etc.; In addition, auto-correlation function method (ACF, Auto Coerrlation Function) and the covariance approximation method based on the received signal correlation properties also is classical portable terminal speed estimation method.

But in the multicarrier systems based on OFDM (OFDM) system such as 3GPP Long Term Evolution (LTE) system, LCR, ZCR etc. is applicable to that the portable terminal speed detection method of single-carrier system is no longer suitable.At present, generally use auto-correlation function method (ACF) to carry out the detection of portable terminal speed in the ofdm system, that is: the channel estimation value according to the reference signal place calculates the maximum Doppler expanding value, and finally calculates portable terminal speed.

The inventor finds: in ofdm system, only the channel estimation value according to the reference signal place detects portable terminal speed, and resulting portable terminal speed testing result is inaccurate.

Summary of the invention

In view of this, the technical problem to be solved in the present invention is, a kind of portable terminal speed detection method and device are provided, and can detect more accurately portable terminal speed in the ofdm system.

For this reason, the embodiment of the invention adopts following technical scheme:

The embodiment of the invention provides a kind of speed detection method of portable terminal, comprising:

Carry out Noise Estimation according to the network side data that receives, obtain noise estimation value; Carry out channel estimating according to the network side data that receives, from the channel estimation value that obtains, extract the channel estimation value of reference signal;

Channel estimation value according to described noise estimation value and described reference signal place is determined instantaneous maximum Doppler expanding value;

Calculate portable terminal speed according to described maximum Doppler expanding value.

Wherein, described channel estimation value according to described noise estimation value and described reference signal place determines that instantaneous maximum Doppler expanding value is specially:

Channel estimation value according to described reference signal place is determined the auto-correlation function sample average; Determine the value at zero point of auto-correlation function according to the channel estimation value at noise estimation value and described reference signal place;

According to described auto-correlation function sample average and the definite normalized auto-correlation function value of value at zero point;

Determine instantaneous maximum Doppler expanding value according to described normalized autocorrelation functions value.

Described channel estimation value according to described reference signal place determines that the auto-correlation function sample average is specially:

Calculate described auto-correlation function sample average R (τ) according to following formula:

$R\left(\mathrm{\τ}\right)=\frac{1}{N_{\mathrm{RS}}(L_{\mathrm{RS}}/2)}\underset{l^{\′}=0}{\overset{L_{\mathrm{RS}}/2-1}{\mathrm{\Σ}}}\underset{k^{\′}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\Σ}}}{\tilde{h}}_{k^{\′},l^{\′}}{{\tilde{h}}^{*}}_{k^{\′},l^{\′}+2};$ ${\tilde{h}}_{k^{\′},l^{\′}}=\frac{{\tilde{r}}_{k^{\′},l^{\′}}}{x_{k^{\′},l^{\′}}};$

Described channel estimation value according to noise estimation value and described reference signal place determines that the value at zero point of auto-correlation function is specially:

Be worth R (0) zero point of calculating described auto-correlation function according to following formula:

$R\left(0\right)=\frac{1}{N_{\mathrm{RS}}{L}_{\mathrm{RS}}}\underset{l^{\′}=0}{\overset{L_{\mathrm{RS}}-1}{\mathrm{\Σ}}}\underset{k^{\′}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\Σ}}}({\left|\right|{\tilde{h}}_{k^{\′},l^{\′}}\left|\right|}^2-{\mathrm{\σ}}^2);$ ${\tilde{h}}_{k^{\′},l^{\′}}=\frac{{\tilde{r}}_{k^{\′},l^{\′}}}{x_{k^{\′},l^{\′}}};$

Wherein, σ ²Be the noise variance of estimating to obtain, i, j are respectively the index of transmitting antenna port and reception antenna port, N _T, N _RBe respectively number of transmit antennas and reception antenna number, N _RSBe the reference signal number in each orthogonal frequency division multiplex OFDM symbol, L _RSBe the OFDM symbolic number of band reference signal,

Be the channel estimation value at reference signal place, x _{K ', l '}Be reference signal, l is the index of OFDM symbol, and k is the index of subcarrier,

It is the received signal estimated value of k subcarrier on l the OFDM symbol.

Described channel estimation value according to described reference signal place determines that the auto-correlation function sample average is specially:

Calculate described auto-correlation function sample average R (τ) according to following formula:

$R\left(\mathrm{\τ}\right)=\frac{1}{{N_T{N}_{R}N}_{\mathrm{RS}}(L_{\mathrm{RS}}/2)}\underset{j=0}{\overset{N_R-1}{\mathrm{\Σ}}}\underset{i=0}{\overset{N_T-1}{\mathrm{\Σ}}}\underset{l^{\′}=0}{\overset{L_{\mathrm{RS}}/2-1}{\mathrm{\Σ}}}\underset{k^{\′}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\Σ}}}{\tilde{h}}_{k^{\′},l^{\′}}^{i,j}{\left({\tilde{h}}_{k^{\′},l^{\′}+2}^{i,j}\right)}^{*};$ ${\tilde{h}}_{k^{\′},l^{\′}}=\frac{{\tilde{r}}_{k^{\′},l^{\′}}}{x_{k^{\′},l^{\′}}};$

Described channel estimation value according to noise estimation value and described reference signal place determines that the value at zero point of auto-correlation function is specially:

Be worth R (0) zero point of calculating described auto-correlation function according to following formula:

$R\left(0\right)=\frac{1}{N_{\mathrm{RS}}{L}_{\mathrm{RS}}}\underset{l^{\′}=0}{\overset{L_{\mathrm{RS}}-1}{\mathrm{\Σ}}}\underset{k^{\′}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\Σ}}}({\left|\right|{\tilde{h}}_{k^{\′},l^{\′}}\left|\right|}^2-{\mathrm{\σ}}^2);$ ${\tilde{h}}_{k^{\′},l^{\′}}=\frac{{\tilde{r}}_{k^{\′},l^{\′}}}{x_{k^{\′},l^{\′}}};$

Wherein, σ ²Be the noise variance of estimating to obtain, i, j are respectively the index of transmitting antenna port and reception antenna port, N _T, N _RBe respectively number of transmit antennas and reception antenna number, N _RSBe the reference signal number in each OFDM symbol, L _RSBe the OFDM symbolic number of band reference signal,

Be the channel estimation value at reference signal place, x _{K ', l '}Be reference signal, l is the index of OFDM symbol, and k is the index of subcarrier,

It is the received signal estimated value of k subcarrier on l the OFDM symbol.

Described according to described auto-correlation function sample average and zero point value determine that normalized auto-correlation function value is specially:

According to formula

Calculate described normalized auto-correlation function value;

Describedly determine that according to described normalized autocorrelation functions value instantaneous maximum Doppler expanding value is specially: according to formula

Or

Calculate described instantaneous maximum Doppler expanding value f _d

Describedly calculate portable terminal speed according to described maximum Doppler expanding value and be specially:

According to described maximum Doppler expanding value from the Doppler that presets table, search with the immediate value of described maximum Doppler expanding value numerical value as best Doppler's expanding value f _{D '}

According to described best Doppler's expanding value f _{D '}Determine the speed of portable terminal.

Describedly determine that according to described best Doppler's expanding value the speed of portable terminal is specially:

According to formula

Calculate the speed v of portable terminal;

Wherein, f _{D '}Be best Doppler's expanding value; f _cThe expression carrier frequency; C represents propagation velocity of electromagnetic wave.

Described search and described calculating between further comprise:

Best Doppler's expanding value to a default value different time is carried out smoothing processing, with the smoothing processing result as described best Doppler's spread estimation value;

Accordingly, the described best Doppler's expanding value as definite foundation of portable terminal speed is: described best Doppler's spread estimation value.

The embodiment of the invention also provides a kind of checkout gear of portable terminal speed, comprising:

First estimation unit is used for carrying out Noise Estimation according to the network side data that receives, and obtains noise estimation value;

Second estimation unit is used for carrying out channel estimating according to the network side data that receives, and extracts the channel estimation value of reference signal from the channel estimation value that obtains;

Determining unit is used for determining instantaneous maximum Doppler expanding value according to the channel estimation value at described noise estimation value and described reference signal place;

Computing unit is used for calculating portable terminal speed according to described maximum Doppler expanding value.

Wherein, described determining unit comprises:

First determines subelement, is used for determining the auto-correlation function sample average according to the channel estimation value at described reference signal place;

Second determines subelement, is used for determining according to the channel estimation value at noise estimation value and described reference signal place the value at zero point of auto-correlation function;

The 3rd determines subelement, is used for according to described auto-correlation function sample average and the definite normalized auto-correlation function value of value at zero point;

The 3rd determines subelement, is used for determining instantaneous maximum Doppler expanding value according to described normalized autocorrelation functions value.

Described computing unit comprises:

Search subelement, be used for according to described maximum Doppler expanding value from the Doppler that presets table search with the immediate value of described maximum Doppler expanding value numerical value as best Doppler's expanding value;

Computation subunit is used for determining according to described best Doppler's expanding value the speed of portable terminal.

Described computing unit also comprises:

Level and smooth subelement is used for best Doppler's expanding value of a default value different time is carried out smoothing processing, and the smoothing processing result as described best Doppler's spread estimation value, is sent to computation subunit with this estimated value.

Technique effect for technique scheme is analyzed as follows:

Channel estimation value according to noise estimation value and reference signal place is determined the maximum Doppler expanding value, and finally calculates portable terminal speed; Thereby in the process that detects portable terminal speed, not only consider the channel estimation value at reference signal place, also considered the influence of noise to portable terminal speed, thereby make portable terminal speed detect the influence that not compared so as to see who is superior by noise, thereby make that detected portable terminal speed is more accurate.

Description of drawings

Fig. 1 is a kind of portable terminal speed detection method of embodiment of the invention schematic flow sheet;

Fig. 2 is the another kind of portable terminal speed detection method of an embodiment of the invention schematic flow sheet;

Fig. 2 a is a reference signal distribution schematic diagram in the LTE system;

Fig. 2 b is the position view after reference signal rearranges;

Fig. 2 c is the position view after reference signal renumbers;

Fig. 2 d is the degree of approximation contrast schematic diagram of Bessel function and multinomial (1) and (2);

Fig. 3 is a kind of portable terminal speed detector of embodiment of the invention structural representation;

Fig. 3 a is the structural representation of determining unit in the embodiment of the invention portable terminal speed detector;

Fig. 3 b calculates the cellular construction schematic diagram in the embodiment of the invention portable terminal speed detector.

Embodiment

Below, be described with reference to the accompanying drawings the realization of the speed detection method and the device of embodiment of the invention portable terminal.

Fig. 1 is the detection method schematic flow sheet of a kind of portable terminal speed of the embodiment of the invention, as shown in Figure 1, comprising:

Step 101: carry out Noise Estimation according to the network side data that receives, obtain noise estimation value.

Step 102: carry out channel estimating according to the network side data that receives, from the channel estimation value that obtains, extract the channel estimation value of reference signal.

Execution sequence between step 101 and the step 102 does not limit here.

Step 103: the channel estimation value according to described noise estimation value and described reference signal place is determined instantaneous maximum Doppler expanding value.

Step 104: calculate portable terminal speed according to described maximum Doppler expanding value.

Embodiment of the invention portable terminal speed detection method shown in Figure 1 is determined the maximum Doppler expanding value according to the channel estimation value at noise estimation value and reference signal place, and finally calculates portable terminal speed; Thereby in the process that detects portable terminal speed except considering the channel estimation value at reference signal place, also considered the influence of noise estimation value to portable terminal speed, thereby make that no matter signal to noise ratio (signal to noise ratio=signal power/noise power) is high or low, all can detect the speed of portable terminal more accurately.

Fig. 2 is the another kind of portable terminal speed detection method of an embodiment of the invention schematic flow sheet, as shown in Figure 2, comprising:

Step 201: carry out Noise Estimation according to the network side data that receives, obtain noise estimation value.

Step 202: carry out channel estimating according to the network side data that receives, from the channel estimation value that obtains, extract the channel estimation value of reference signal.

Execution sequence between step 201 and the step 202 does not limit here.

Wherein, Fig. 2 a has provided the exemplary plot that reference signal distributes in the LTE system, particularly, only the drawn length (during general cyclic prefix (CP)) of a subframe of time orientation (abscissa), frequency domain direction 12 subcarriers that only drawn, and only represented reference signal distribution situation on the transmitting antenna port.The part of having carried out mark among Fig. 2 a is represented the position at reference signal place, in the actual conditions different cell reference signals is had different side-play amounts on frequency domain, different transmitting antenna ports is had different distributions, but the relative position between each reference signal substantially to figure in similar, all adopt this discrete reference signal location mode.

If r _{K, l}Be the received signal at k subcarrier place on l the OFDM symbol, 0≤k＜N wherein _Sc, 0≤l＜N _Symb, N _ScBe downlink sub-carrier sum, N _SymbRepresent the OFDM symbolic number that comprises in the subframe, N during common CP _Symb=14, N during extended pattern CP _Symb=12.Because follow-up the received signal of being concerned about the reference signal place, for simplicity, the signal at all non-reference signal places can be removed and put aside, obtain schematic diagram such as Fig. 2 b after the reference signal position rearranges; Again back shown in Fig. 2 c, wherein to being numbered of reference signal position

Position relation in original running time-frequency resource can be clear that by this three secondary figure.

In view of the above, can obtain the channel estimation value at all reference signal places:

${\tilde{h}}_{k^{\′},l^{\′}}=\frac{{\tilde{r}}_{k^{\′},l^{\′}}}{x_{k^{\′},l^{\′}}}---\left(1\right)$

Be the channel estimation value at reference signal place, x _{K ', l '}Be reference signal,

It is the received signal estimated value of k subcarrier on l the OFDM symbol.

Step 203: the channel estimation value according to described reference signal place is determined the auto-correlation function sample average.

Concrete, can use following formula (2) or (3) to calculate described auto-correlation function sample average R (τ):

$R\left(\mathrm{\τ}\right)=\frac{1}{N_{\mathrm{RS}}(L_{\mathrm{RS}}/2)}\underset{l^{\′}=0}{\overset{L_{\mathrm{RS}}/2-1}{\mathrm{\Σ}}}\underset{k^{\′}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\Σ}}}{\tilde{h}}_{k^{\′},l^{\′}}{{\tilde{h}}^{*}}_{k^{\′},l^{\′}+2}---\left(2\right)$

$R\left(\mathrm{\τ}\right)=\frac{1}{{N_T{N}_{R}N}_{\mathrm{RS}}(L_{\mathrm{RS}}/2)}\underset{j=0}{\overset{N_R-1}{\mathrm{\Σ}}}\underset{i=0}{\overset{N_T-1}{\mathrm{\Σ}}}\underset{l^{\′}=0}{\overset{L_{\mathrm{RS}}/2-1}{\mathrm{\Σ}}}\underset{k^{\′}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\Σ}}}{\tilde{h}}_{k^{\′},l^{\′}}^{i,j}{\left({\tilde{h}}_{k^{\′},l^{\′}+2}^{i,j}\right)}^{*}---\left(3\right)$

Wherein, formula (2) is a computing formula of calculating the auto-correlation function sample average when not using multiple-input and multiple-output (MIMO) technology among the LTE; Formula (3) is a computing formula of calculating the auto-correlation function sample average when using the MIMO technology among the LTE.

Step 204: the value at zero point of determining auto-correlation function according to the channel estimation value at described noise estimation value and described reference signal place.

Concrete, be worth R (0) zero point that can use following formula (4) or (5) to calculate described auto-correlation function:

$R\left(0\right)=\frac{1}{N_{\mathrm{RS}}{L}_{\mathrm{RS}}}\underset{l^{\′}=0}{\overset{L_{\mathrm{RS}}-1}{\mathrm{\Σ}}}\underset{k^{\′}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\Σ}}}({\left|\right|{\tilde{h}}_{k^{\′},l^{\′}}\left|\right|}^2-{\mathrm{\σ}}^2)---\left(4\right)$

$R\left(0\right)=\frac{1}{{N_T{N}_{R}N}_{\mathrm{RS}}{L}_{\mathrm{RS}}}\underset{j=0}{\overset{N_R-1}{\mathrm{\Σ}}}\underset{i=0}{\overset{N_T-1}{\mathrm{\Σ}}}\underset{l^{\′}=0}{\overset{L_{\mathrm{RS}}-1}{\mathrm{\Σ}}}\underset{k^{\′}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\Σ}}}({\left|\right|{\tilde{h}}_{k^{\′},l^{\′}}^{i,j}\left|\right|}^2-{\mathrm{\σ}}^2)---\left(5\right)$

Wherein, formula (4) is a computing formula of calculating auto-correlation function value at zero point when not using the MIMO technology among the LTE; Formula (5) is a computing formula of calculating auto-correlation function value at zero point when using the MIMO technology among the LTE.

For the formula in step 203 and the step 204, σ ²Be the noise variance of estimating to obtain, i, j are respectively the index of transmitting antenna port and reception antenna port, N _T, N _RBe respectively number of transmit antennas and reception antenna number, N _RSBe the reference signal number in the OFDM symbol of each band reference signal, L _RSThe OFDM symbolic number of the band reference signal of using when estimating for Doppler,

Be the channel estimation value at reference signal place, x _{K ', l '}Be reference signal, l is the index of OFDM symbol, and k is the index of subcarrier,

It is the received signal estimated value of k subcarrier on l the OFDM symbol.

Execution sequence between step 203 and the step 204 does not limit yet.

Step 205: according to described auto-correlation function sample average and the definite normalized auto-correlation function value of value at zero point.

Concrete, can use formula (6) to calculate described normalized auto-correlation function value:

$R_t\left(\mathrm{\τ}\right)=\frac{\mathrm{real}\left\{R_t\left(\mathrm{\τ}\right)\right\}}{R_t\left(0\right)},---\left(6\right)$

Wherein, real{} represents plural number is got the operation of real part, and τ can get 0.5ms here.

Step 206: determine instantaneous maximum Doppler expanding value according to described normalized autocorrelation functions value.

Inversion process for first kind zero Bessel function, because first kind zero Bessel function is very complicated, method commonly used on the engineering is to be undertaken by the method for tabling look-up, but this method often needs extra memory space, the precision that needs is high more, the form of storage is big more, if reduce the storage of form, will have a strong impact on precision.Here the method for Jie Shaoing is to calculate in real time with a kind of polynomial approximation method, and does not need to store form.

Can get

$J_0\left(x\right)\≈{(1-\frac{x^2}{8})}^2---\left(A\right);$

If it is further simplify, desirable

$J_0\left(x\right)\≈1-\frac{x^2}{4}---\left(B\right)$

This (A) (B) degree of approximation of two polynomial approximations and Bessel function shown in Fig. 2 d.

As seen multinomial (A) is very approaching with Bessel function, and the error of multinomial (2) neither be very big, adopts such polynomial function to invert to become and be easy to, and do not need to store form.Concrete, can use formula (7) or (8) to carry out the calculating of described maximum Doppler expanding value:

$f_d=\frac{\sqrt{2}}{\mathrm{\&pi;\&tau;}}{(1-{\mathrm{<figure-callout\; id="1"\; label="R\; t"\; filenames="H200910055404XE0000042.png"\; state="\{\{state\}\}">R</figure-callout>}}_t^{}\left(\mathrm{\&tau;}\right))}^{1/2}---\left(7\right)$

$f_d=\frac{1}{\mathrm{\&pi;\&tau;}}{(1-R_t\left(\mathrm{\&tau;}\right))}^{1/2}---\left(8\right)$

In actual applications, can determine to use formula (7) or formula (8) to carry out the calculating of described maximum Doppler expanding value according to portable terminal speed accuracy of detection.

By using above-mentioned formula to calculate the maximum Doppler expanding value, more accurate with respect to the method for tabling look-up, saved more memory space.

Step 207: according to described maximum Doppler expanding value from the Doppler that presets table, search with the immediate value of described maximum Doppler expanding value numerical value as best Doppler's expanding value f _d

Wherein, the index value in described Doppler's table is the representative value of Doppler's expansion of series of discrete, and these values can be determined by the demand of simulation result and practical application.

Step 208: the best Doppler's expanding value to a default value different time is carried out smoothing processing, with the smoothing processing result as described best Doppler's spread estimation value f _{D '}

Particularly, calculating to auto-correlation function all is to replace the operation of asking expectation by a plurality of data are averaged, therefore the data volume that participates in statistics is big more, the accuracy of estimating is high more, therefore the statistics that participates in estimating can also use the data of a plurality of subframes to average or smoothly except the data of using a subframe.A kind of simple smoothing method can for:

${\hat{f}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="H200910055404XE0000042.png"\; state="\{\{state\}\}">d</figure-callout>}1}=f_{d1}$ (9)

${\hat{f}}_{\mathrm{di}}=\mathrm{\&alpha;}{f}_{\mathrm{di}-1}+(1-\mathrm{\&alpha;})f_{\mathrm{di}},i>1$

F wherein _DiThe instantaneous value that the maximum Doppler that expression utilizes current subframe to estimate is expanded,

Estimated value after expression is level and smooth, α is a forgetting factor, 0≤α＜1.

Step 208 is an optional step, can not carry out described smooth operation that is:, and directly by the speed calculation in best Doppler's expanding value execution in step 209.

By the smoothing processing in this step, can make that final detected portable terminal velocity amplitude is more accurate.

Step 209: the speed of calculating portable terminal according to the estimated value of described best Doppler's expansion.

Concrete, can carry out the calculating of described portable terminal speed according to formula (10):

$v=\frac{f_{d^{\&prime;}}\&CenterDot;c}{f_c}---\left(1\right)$

The detection method of embodiment of the invention portable terminal speed shown in Figure 2 has provided more concrete portable terminal speed implementation method, progressively detects the speed of portable terminal by the network side data that receives; And, consider the influence that noise detects speed during the course, thereby obtained more accurate portable terminal velocity amplitude.

Fig. 3 is the checkout gear structural representation of a kind of portable terminal speed of the embodiment of the invention, as shown in Figure 3, comprising:

First estimation unit 310 is used for carrying out Noise Estimation according to the network side data that receives, and obtains noise estimation value;

Second estimation unit 320 is used for carrying out channel estimating according to the network side data that receives, and extracts the channel estimation value of reference signal from the channel estimation value that obtains;

Determining unit 330 is used for determining instantaneous maximum Doppler expanding value according to the channel estimation value at described noise estimation value and described reference signal place;

Computing unit 340 is used for calculating portable terminal speed according to described maximum Doppler expanding value.

Further, shown in Fig. 3 a, described determining unit 330 can also comprise:

First determines subelement 3301, is used for determining the auto-correlation function sample average according to the channel estimation value at described reference signal place;

Second determines subelement 3302, is used for determining according to the channel estimation value at noise estimation value and described reference signal place the value at zero point of auto-correlation function;

The 3rd determines subelement 3303, is used for according to described auto-correlation function sample average and the definite normalized auto-correlation function value of value at zero point;

The 4th determines subelement 3304, is used for determining instantaneous maximum Doppler expanding value according to described normalized autocorrelation functions value.

Shown in Fig. 3 b, described computing unit 340 may further include:

Search subelement 3401, be used for according to described maximum Doppler expanding value from the Doppler that presets table search with the immediate value of described maximum Doppler expanding value numerical value as best Doppler's expanding value;

Computation subunit 3402 is used for determining according to described best Doppler's expanding value the speed of portable terminal.

Further, described searching between subelement 3401 and the computation subunit 3402 can also comprise:

Level and smooth subelement 3403 is used for best Doppler's expanding value of a default value different time is carried out smoothing processing, and the smoothing processing result as described best Doppler's spread estimation value, is sent to computation subunit with this estimated value.Accordingly, computation subunit 3402 is determined the speed of portable terminal according to described best Doppler's spread estimation value.

Embodiment of the invention portable terminal speed detector shown in Fig. 3～Fig. 3 b is determined the maximum Doppler expanding value according to the channel estimation value at noise estimation value and reference signal place, and finally calculates portable terminal speed; Thereby in the process that detects portable terminal speed,, also considered the influence of noise, thereby, all can detect the speed of portable terminal more accurately no matter make that signal to noise ratio is high or low to portable terminal speed except considering the channel estimation value at reference signal place.

The detection method of embodiment of the invention portable terminal speed and device can be applied in the entities such as portable terminal or base station.

In addition, though in embodiments of the present invention how with the LTE system for example,, embodiment of the invention portable terminal speed detection method and device also go for other ofdm systems or MIMO-OFDM system.

One of ordinary skill in the art will appreciate that, the process of realization the foregoing description portable terminal speed detection method can be finished by the relevant hardware of program command, described program can be stored in the read/write memory medium, and this program is carried out the corresponding step in the said method when carrying out.Described storage medium can be as ROM/RAM, magnetic disc, CD etc.

The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (12)

1. the speed detection method of a portable terminal is characterized in that, comprising:

Carry out Noise Estimation according to the network side data that receives, obtain noise estimation value; Carry out channel estimating according to the network side data that receives, from the channel estimation value that obtains, extract the channel estimation value of reference signal;

Channel estimation value according to described noise estimation value and described reference signal place is determined instantaneous maximum Doppler expanding value;

Calculate portable terminal speed according to described maximum Doppler expanding value.

2. method according to claim 1 is characterized in that, described channel estimation value according to described noise estimation value and described reference signal place determines that instantaneous maximum Doppler expanding value is specially:

Channel estimation value according to described reference signal place is determined the auto-correlation function sample average; Determine the value at zero point of auto-correlation function according to the channel estimation value at noise estimation value and described reference signal place;

According to described auto-correlation function sample average and the definite normalized auto-correlation function value of value at zero point;

Determine instantaneous maximum Doppler expanding value according to described normalized autocorrelation functions value.

3. method according to claim 2 is characterized in that, described channel estimation value according to described reference signal place determines that the auto-correlation function sample average is specially:

Calculate described auto-correlation function sample average R (τ) according to following formula:

$R\left(\mathrm{\&tau;}\right)=\frac{1}{N_{\mathrm{RS}}(L_{\mathrm{RS}}/2)}\underset{l^{\&prime;}=0}{\overset{L_{\mathrm{RS}}/2-1}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\&Sigma;}}}{\tilde{h}}_{k^{\&prime;},l^{\&prime;}}{{\tilde{h}}^{*}}_{k^{\&prime;},l^{\&prime;}+2};$ ${\tilde{h}}_{k^{\&prime;},l^{\&prime;}}=\frac{{\tilde{r}}_{k^{\&prime;},l^{\&prime;}}}{x_{k^{\&prime;},l^{\&prime;}}};$

Described channel estimation value according to noise estimation value and described reference signal place determines that the value at zero point of auto-correlation function is specially:

Be worth R (0) zero point of calculating described auto-correlation function according to following formula:

$R\left(0\right)=\frac{1}{N_{\mathrm{RS}}{L}_{\mathrm{RS}}}\underset{l^{\&prime;}=0}{\overset{L_{\mathrm{RS}}-1}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\&Sigma;}}}({\left|\right|{\tilde{h}}_{k^{\&prime;},l^{\&prime;}}\left|\right|}^2-{\mathrm{\&sigma;}}^2);$ ${\tilde{h}}_{k^{\&prime;},l^{\&prime;}}=\frac{{\tilde{r}}_{k^{\&prime;},l^{\&prime;}}}{x_{k^{\&prime;},l^{\&prime;}}};$

Wherein, σ ²Be the noise variance of estimating to obtain, i, j are respectively the index of transmitting antenna port and reception antenna port, N _T, N _RBe respectively number of transmit antennas and reception antenna number, N _RSBe the reference signal number in each orthogonal frequency division multiplex OFDM symbol, L _RSBe the OFDM symbolic number of band reference signal, Be the channel estimation value at reference signal place, x _{K ', l '}Be reference signal, l is the index of OFDM symbol, and k is the index of subcarrier,

It is the received signal estimated value of k subcarrier on l the OFDM symbol.

4. method according to claim 2 is characterized in that, described channel estimation value according to described reference signal place determines that the auto-correlation function sample average is specially:

Calculate described auto-correlation function sample average R (τ) according to following formula:

$R\left(\mathrm{\&tau;}\right)=\frac{1}{N_T{N}_R{N}_{\mathrm{RS}}(L_{\mathrm{RS}}/2)}\underset{j=0}{\overset{N_R-1}{\mathrm{\&Sigma;}}}\underset{i=0}{\overset{N_T-1}{\mathrm{\&Sigma;}}}\underset{l^{\&prime;}=0}{\overset{L_{\mathrm{RS}}/2-1}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\&Sigma;}}}{\tilde{h}}_{k^{\&prime;},l^{\&prime;}}^{i,j}{\left({\tilde{h}}_{k^{\&prime;},l^{\&prime;}+2}^{i,j}\right)}^{*};$ ${\tilde{h}}_{k^{\&prime;},l^{\&prime;}}=\frac{{\tilde{r}}_{k^{\&prime;},l^{\&prime;}}}{x_{k^{\&prime;},l^{\&prime;}}};$

Described channel estimation value according to noise estimation value and described reference signal place determines that the value at zero point of auto-correlation function is specially:

Be worth R (0) zero point of calculating described auto-correlation function according to following formula:

$R\left(0\right)=\frac{1}{N_{\mathrm{RS}}{L}_{\mathrm{RS}}}\underset{l^{\&prime;}=0}{\overset{L_{\mathrm{RS}}-1}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=0}{\overset{N_{\mathrm{RS}}-1}{\mathrm{\&Sigma;}}}({\left|\right|{\tilde{h}}_{k^{\&prime;},l^{\&prime;}}\left|\right|}^2-{\mathrm{\&sigma;}}^2);$ ${\tilde{h}}_{k^{\&prime;},l^{\&prime;}}=\frac{{\tilde{r}}_{k^{\&prime;},l^{\&prime;}}}{x_{k^{\&prime;},l^{\&prime;}}};$

Wherein, σ ²Be the noise variance of estimating to obtain, i, j are respectively the index of transmitting antenna port and reception antenna port, N _T, N _RBe respectively number of transmit antennas and reception antenna number, N _RSBe the reference signal number in each OFDM symbol, L _RSBe the OFDM symbolic number of band reference signal, Be the channel estimation value at reference signal place, x _{K ', j '}Be reference signal, l is the index of OFDM symbol, and k is the index of subcarrier,

It is the received signal estimated value of k subcarrier on l the OFDM symbol.

5. according to claim 3 or 4 described methods, it is characterized in that, described according to described auto-correlation function sample average and zero point value determine that normalized auto-correlation function value is specially:

According to formula

Calculate described normalized auto-correlation function value;

Describedly determine that according to described normalized autocorrelation functions value instantaneous maximum Doppler expanding value is specially: according to formula

Or

Calculate described instantaneous maximum Doppler expanding value f _d

6. according to each described method of claim 1 to 4, it is characterized in that, describedly calculate portable terminal speed according to described maximum Doppler expanding value and be specially:

According to described maximum Doppler expanding value from the Doppler that presets table, search with the immediate value of described maximum Doppler expanding value numerical value as best Doppler's expanding value f _{D '}

According to described best Doppler's expanding value f _{D '}Determine the speed of portable terminal.

7. method according to claim 6 is characterized in that, describedly determines that according to described best Doppler's expanding value the speed of portable terminal is specially:

According to formula

Calculate the speed v of portable terminal;

Wherein, f _{D '}Be best Doppler's expanding value; f _cThe expression carrier frequency; C represents propagation velocity of electromagnetic wave.

8. method according to claim 6 is characterized in that, described search and described calculating between further comprise:

Best Doppler's expanding value to a default value different time is carried out smoothing processing, with the smoothing processing result as described best Doppler's spread estimation value;

Accordingly, the described best Doppler's expanding value as definite foundation of portable terminal speed is: described best Doppler's spread estimation value.

9. the checkout gear of a portable terminal speed is characterized in that, comprising:

First estimation unit is used for carrying out Noise Estimation according to the network side data that receives, and obtains noise estimation value;

Second estimation unit is used for carrying out channel estimating according to the network side data that receives, and extracts the channel estimation value of reference signal from the channel estimation value that obtains;

Determining unit is used for determining instantaneous maximum Doppler expanding value according to the channel estimation value at described noise estimation value and described reference signal place;

Computing unit is used for calculating portable terminal speed according to described maximum Doppler expanding value.

10. device according to claim 9 is characterized in that, described determining unit comprises: first determines subelement, is used for determining the auto-correlation function sample average according to the channel estimation value at described reference signal place;

Second determines subelement, is used for determining according to the channel estimation value at noise estimation value and described reference signal place the value at zero point of auto-correlation function;

The 3rd determines subelement, is used for according to described auto-correlation function sample average and the definite normalized auto-correlation function value of value at zero point;

The 3rd determines subelement, is used for determining instantaneous maximum Doppler expanding value according to described normalized autocorrelation functions value.

11. device according to claim 10 is characterized in that, described computing unit comprises:

Search subelement, be used for according to described maximum Doppler expanding value from the Doppler that presets table search with the immediate value of described maximum Doppler expanding value numerical value as best Doppler's expanding value;

Computation subunit is used for determining according to described best Doppler's expanding value the speed of portable terminal.

12. device according to claim 11 is characterized in that, described computing unit also comprises:

Level and smooth subelement is used for best Doppler's expanding value of a default value different time is carried out smoothing processing, and the smoothing processing result as described best Doppler's spread estimation value, is sent to computation subunit with this estimated value.

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