阅读说明：本技术 一种终端运动环境识别的方法及装置 (method and device for identifying terminal motion environment ) 是由 李卫国 胡伯承 李俊强 于 2016-04-28 设计创作，主要内容包括：一种终端运动环境识别的方法及装置,所述运动环境包括高铁环境,所述方法包括：获取预设的第一时长内所述终端的运动参数值；拟合得到所述终端的运动参数值随时间变化的曲线；判断所述曲线是否与预设的特征曲线匹配；其中,所述预设的特征曲线与所述高铁环境对应；当确定所述曲线与预设的特征曲线匹配时,识别所述终端处于所述高铁环境中。采用上述方案可以准确地识别终端处于高铁环境。(A method and a device for identifying a motion environment of a terminal, wherein the motion environment comprises a high-speed rail environment, and the method comprises the following steps: acquiring a motion parameter value of the terminal within a preset first time length; fitting to obtain a curve of the motion parameter value of the terminal changing along with time; judging whether the curve is matched with a preset characteristic curve or not; the preset characteristic curve corresponds to the high-speed rail environment; and when the curve is determined to be matched with a preset characteristic curve, recognizing that the terminal is in the high-speed rail environment. By adopting the scheme, the terminal can be accurately identified to be in a high-speed rail environment.)

1. A method for recognizing a motion environment of a terminal, wherein the motion environment comprises a high-speed rail environment, and the method comprises the following steps:

acquiring a motion parameter value of the terminal within a preset first time length;

Fitting to obtain a curve of the motion parameter value of the terminal changing along with time;

Judging whether the curve is matched with a preset characteristic curve or not; the preset characteristic curve corresponds to the high-speed rail environment;

Identifying that the terminal is in the high-speed rail environment when it is determined that the curve matches the characteristic curve.

2. The method of claim 1, wherein the motion parameter value is a doppler frequency shift value or a frequency offset estimation value.

3. The method for recognizing the motion environment of the terminal according to claim 1, further comprising, after determining that the terminal is in the high-speed rail environment:

Switching to a communication mode corresponding to the high-speed rail environment, and keeping a preset second time length;

And continuously acquiring the motion parameter value of the terminal.

4. The method for recognizing the motion environment of the terminal according to claim 3, further comprising, after switching to the communication mode corresponding to the high-speed rail environment:

Within a preset third time length, when the curve is not matched with the preset characteristic curve, the communication mode corresponding to the high-speed rail environment is exited; the third duration is greater than the second duration.

5. The method for terminal motion environment recognition according to claim 1, wherein each period of the characteristic curve includes one peak and two troughs or includes one trough and two peaks.

6. An apparatus for recognizing a motion environment of a terminal, the motion environment including a high-speed rail environment, comprising:

the acquisition unit is suitable for acquiring the motion parameter value of the terminal within a preset first duration;

the fitting unit is suitable for fitting to obtain a curve of the motion parameter value of the terminal changing along with time;

The judging unit is suitable for judging whether the curve is matched with a preset characteristic curve or not; the preset characteristic curve corresponds to the high-speed rail environment;

and the motion environment recognition unit is suitable for recognizing that the terminal is in the high-speed rail environment when the judging unit determines that the curve is matched with a preset characteristic curve.

7. The apparatus of claim 6, wherein the motion parameter value is a doppler shift value or a frequency offset estimation value.

8. the apparatus for recognizing a motion environment of a terminal according to claim 6, further comprising:

The switching unit is suitable for switching to a communication mode corresponding to the high-speed rail environment and keeping a preset second time length after the judging unit determines that the terminal is in the high-speed rail environment;

The obtaining unit is further adapted to continue to obtain the motion parameter value of the terminal after switching to the communication mode corresponding to the high-speed rail environment.

9. The apparatus for recognizing a terminal motion environment according to claim 8, wherein the switching unit is further adapted to exit the communication mode corresponding to the high-speed rail environment when the curve does not match the preset characteristic curve within a preset third time period after switching to the communication mode corresponding to the high-speed rail environment; the third duration is greater than the second duration.

10. The apparatus for terminal motion environment recognition according to claim 6, wherein each period of the characteristic curve includes one peak and two valleys, or includes one valley and two peaks.

Technical Field

The invention relates to the field of communication, in particular to a method and a device for identifying a terminal motion environment.

Background

At present, the high-speed railway develops rapidly, and how to obtain a high-quality wireless communication effect in a high-speed rail environment with the speed as high as 300-400 km/h becomes a difficult point in the industry. In order to improve the communication quality of the wireless terminal in a high-speed rail environment, the motion environment of the terminal is firstly identified as the high-speed rail environment.

Currently, whether the terminal is in a high-speed rail environment is judged through the movement speed, that is, if the movement speed of the terminal exceeds a certain value, the terminal is determined to be in the high-speed rail environment. The movement speed of the terminal is obtained through the value of Doppler frequency shift; or by the frequency of cell switching by the terminal over a period of time.

However, if the motion environment of the terminal is determined by the above-described method, it may be impossible to recognize that the terminal is in a high-speed rail environment or to erroneously recognize that the terminal is in a high-speed rail environment.

Disclosure of Invention

The invention solves the problem of accurately identifying the terminal in a high-speed rail environment.

In order to solve the above problem, an embodiment of the present invention provides a method for identifying a motion environment of a terminal, where the motion environment includes a high-speed rail environment, and the method includes: acquiring a motion parameter value of the terminal within a preset first time length; fitting to obtain a curve of the motion parameter value of the terminal changing along with time; judging whether the curve is matched with a preset characteristic curve or not; the preset characteristic curve corresponds to the high-speed rail environment; identifying that the terminal is in the high-speed rail environment when it is determined that the curve matches the characteristic curve.

optionally, the motion parameter value is a doppler frequency shift value or a frequency offset estimation value.

optionally, after determining that the terminal is in the high-speed rail environment, the method further includes: switching to a communication mode corresponding to the high-speed rail environment, and keeping a preset second time length; and continuously acquiring the motion parameter value of the terminal.

Optionally, after switching to the communication mode corresponding to the high-speed rail environment, the method further includes: within a preset third time length, when the curve is not matched with the preset characteristic curve, the communication mode corresponding to the high-speed rail environment is exited; the third duration is greater than the second duration.

Optionally, each period of the characteristic curve comprises one peak and two troughs or one trough and two peaks.

the embodiment of the invention provides a device for identifying a terminal motion environment, wherein the motion environment comprises a high-speed rail environment, and the device comprises: the acquisition unit is suitable for acquiring the motion parameter value of the terminal within a preset first duration; the fitting unit is suitable for fitting to obtain a curve of the motion parameter value of the terminal changing along with time; the judging unit is suitable for judging whether the curve is matched with a preset characteristic curve or not; the preset characteristic curve corresponds to the high-speed rail environment; and the motion environment recognition unit is suitable for recognizing that the terminal is in the high-speed rail environment when the judging unit determines that the curve is matched with a preset characteristic curve.

Optionally, the motion parameter value is a doppler frequency shift value or a frequency offset estimation value.

optionally, the apparatus further comprises: the switching unit is suitable for switching to a communication mode corresponding to the high-speed rail environment and keeping a preset second time length after the judging unit determines that the terminal is in the high-speed rail environment; the obtaining unit is further adapted to continue to obtain the motion parameter value of the terminal after switching to the communication mode corresponding to the high-speed rail environment.

optionally, the switching unit is further adapted to exit the communication mode corresponding to the high-speed rail environment when the curve does not match the preset characteristic curve within a preset third time period after switching to the communication mode corresponding to the high-speed rail environment; the third duration is greater than the second duration.

Optionally, each period of the characteristic curve comprises one peak and two troughs or one trough and two peaks.

compared with the prior art, the technical scheme of the invention has the following advantages:

When the terminal is in a high-speed rail environment, the change rule of the motion parameter value of the terminal in a certain time period has a specific characteristic curve characteristic, so that a curve of the motion parameter value of the terminal changing along with time is obtained through fitting, and when the curve is matched with the preset characteristic curve, the terminal is determined to be in the high-speed rail environment, namely, the terminal is identified to be in the high-speed rail environment through the change trend of the motion parameter value of the terminal, so that the situation that the motion environment of the terminal is identified by mistake or the situation that the motion environment where the terminal is located cannot be identified due to improper detection of the motion speed of the terminal can be avoided, and the situation that the terminal is in the high-speed rail environment can be accurately identified.

drawings

Fig. 1 is a flowchart illustrating a method for identifying a terminal motion environment according to an embodiment of the present invention;

Fig. 2 is a diagram of a scenario of a mutual movement between a high-speed rail and a base station in an embodiment of the present invention;

FIG. 3 is a time-varying fit of the Doppler shift of a terminal in a high-speed rail environment according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating a relationship between Doppler shift and frequency offset estimation according to an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of an apparatus for recognizing a terminal motion environment in an embodiment of the present invention.

Detailed Description

In a high-speed rail environment, doppler shift is caused by high-speed motion, thereby causing doppler effect. The doppler effect is that the frequency of a signal received by a receiving end changes due to high-speed relative motion between the transmitting end and the receiving end, and the frequency change can reduce the demodulation performance of the receiving end. The magnitude of the doppler shift can be calculated using the following equation (1):

Wherein V is the vehicle speed, C is the light speed, and f is the working frequency.

When the train approaches the base station, the Doppler frequency shift is positive; the doppler shift is negative when the train is far from the base station. If the A place is a point when the train is close to the base station, and the B place is a point when the train is far away from the base station. f0 is the frequency of the downlink channel before being affected by Doppler frequency offset, f1 is the frequency of the uplink channel before being affected by Doppler frequency offset, V is the running speed of the train, f1+2fd is the frequency of the uplink channel at the A site, f0+ fd is the frequency of the downlink channel at the A site, f1-2fd is the frequency of the uplink channel at the B site, and f0-fd is the frequency of the downlink channel at the B site.

For example, the respective radio frequencies of 1.9GHz and 2.6GHz are used, and the Doppler frequency offsets caused by uplink and downlink when the moving speed of the train is 120km/h, 300km/h and 350km/h are shown in Table 1.

TABLE 1

as can be seen from table 1, if a user uses a terminal on a high-speed rail, the doppler effect has a great influence on the communication quality of the terminal. And the development of the existing high-speed railway is very fast, so that how to obtain a high-quality wireless communication effect in a high-speed rail environment with the speed of 300-400 km/h becomes a difficult point in the industry. In order to improve the communication quality of the wireless terminal in a high-speed rail environment, the motion environment of the terminal is firstly identified as the high-speed rail environment.

Currently, whether the terminal is in a high-speed rail environment is judged through the movement speed, that is, if the movement speed of the terminal exceeds a certain value, the terminal is determined to be in the high-speed rail environment. The movement speed of the terminal is obtained through the value of Doppler frequency shift; or by the frequency of cell switching by the terminal over a period of time.

There are at least two drawbacks to the method of identifying a high-speed rail environment using values of doppler shift: on one hand, because the estimation algorithms have certain errors, the movement speeds of 120km/h, 200km/h, 250km/h and the like can not be completely distinguished, so that the movement environments of expressways and the like can be mistakenly judged as high-speed rail environments; on the other hand, after frequency offset compensation, a large doppler shift value may not be calculated, and thus a high-speed rail environment may not be identified. The method for identifying the high-speed rail environment by judging the movement speed through the cell switching frequency of the terminal in a period of time also has at least two defects: on one hand, relatively high movement speeds may not be distinguished, which may eventually lead to misjudgment of movement environments such as highways as high-speed rail environments, and on the other hand, when the mobile terminal moves in microcells and picocells, because the coverage area of the cells is small, if the microcells and picocells cover densely, the cell switching frequency within a certain time is also high, and at this time, the mobile terminal may be mistakenly identified as a high-speed rail environment. That is, if the motion environment of the terminal is judged by the above-described method, it may be impossible to recognize that the terminal is in a high-speed rail environment or to erroneously recognize that the terminal is in a high-speed rail environment.

In order to solve the above problem, in the embodiment of the present invention, a curve of a motion parameter value of the terminal changing with time is obtained through fitting, and when the curve conforms to the preset characteristic curve, it is determined that the terminal is in the high-speed rail environment, that is, the terminal is identified as being in the high-speed rail environment through a change trend of the motion parameter value of the terminal, so that it is possible to avoid that the motion environment of the terminal is identified by mistake or the motion environment where the terminal is located cannot be identified due to an improper detection of a motion speed of the terminal, and thus, it is possible to accurately identify that the terminal is in the high-speed rail environment.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

A schematic diagram of a method for identifying a terminal motion environment in an embodiment of the present invention is shown below, as shown in fig. 1, where the motion environment includes a high-speed rail environment, and the method is described in detail below:

S11: and acquiring a motion parameter value of the terminal within a preset first time length.

in a specific implementation, the motion parameter value may be a doppler shift value of the terminal.

in a specific implementation, the first duration may be up to ten seconds, or an integer multiple of the ten seconds. As long as in the first duration, the time-varying curve of the motion parameter value of the terminal may be used to determine whether the motion parameter value matches at least one of the characteristic curves.

s12: and fitting to obtain a curve of the motion parameter value of the terminal changing along with time.

S13: judging whether the curve is matched with a preset characteristic curve or not; wherein the preset characteristic curve corresponds to the high-speed rail environment.

it should be noted that the base stations disposed beside the high-speed rail line can be linearly covered along the railway, and a scene diagram of the mutual movement between the high-speed rail and the base stations in the embodiment of the present invention is shown below, as shown in fig. 2, DS is the distance from the base station to the railway, Dmin is the distance between the base stations, v is the moving speed of the train, and is m/s, t is time and is second, and θ represents the included angle between the high-speed rail track and the connecting line between the current position of the vehicle and the base station.

And if the point A is taken as the timing starting point, when 0 ≦ t ≦ Ds/v, the angle θ (t) of the angle θ changing with time satisfies the relationship shown in the formula (2):

When Ds/v < t.ltoreq.2Ds/v, θ (t) satisfies the relationship shown in formula (3):

When t >2Ds/v, θ (t) satisfies the relationship shown in equation (4):

cosθ(t)＝cosθ(t mod(2D/v)) (4)

Therefore, in an embodiment of the present invention, the relationship between the doppler shift of the terminal and the time in the high-speed rail environment can be expressed according to the following formula (5):

f(t)＝fcosθ(t) (5)

Wherein: fs (t) is the Doppler shift at t, and fd is the maximum Doppler shift over a time period of 0-t.

in a specific implementation, when Ds is 300m, Dmin is 2m, V is 300km/h, and fd is 750HZ, a coordinate system is established with a railway as a horizontal axis and point a as an origin, and when a high-speed rail moves from point a to point B, a change curve of the doppler frequency shift of a terminal located on the high-speed rail can be as shown in fig. 3, as can be seen from fig. 3, when the high-speed rail travels on the high-speed rail and passes through a linear base station, a phenomenon that the doppler frequency shift of the terminal on the high-speed rail changes with time alternately appears, that is, a "zigzag feature is satisfied, in other words, a rectangular wave shape is satisfied. And the characteristic of the periodic figure-of-several Doppler frequency shift is specific to a high-speed rail environment and does not exist in other environments such as a highway, a microcell and the like.

Therefore, in a specific implementation, the predetermined characteristic curve may be a curve in the shape of a rectangular wave or a continuous curve in the shape of a zigzag. The curve is matched with the preset characteristic curve, and does not mean that the curve is strictly a rectangular wave or a "few" word, as long as the curve has a characteristic that the continuous fluctuation is regular, such as a high or low of the rectangular wave or the "few" word.

in a specific implementation, each period of the characteristic curve comprises one peak and two troughs or one trough and two peaks.

In an embodiment of the present invention, the period may be ten seconds, that is, within a shortest ten seconds, a curve obtained by fitting the doppler shift of the terminal in a high-speed rail environment with the change of time may be matched with the "geometric" feature.

it should be noted that, due to the single-path channel, the doppler effect is reflected in the frequency offset estimation, the relationship between the doppler shift and the frequency offset estimation value is shown in fig. 4, the horizontal axis represents the number of subframes, wherein each subframe is 1ms, and the vertical axis may represent the doppler shift or the frequency offset estimation value, wherein the curve 41 is a curve of the doppler shift ftotal, and the vertical axis corresponds to the doppler shift; the curve 42 is a curve of the frequency offset estimation value fHST, and the vertical axis corresponds to the frequency offset estimation value, and it can be seen from the figure that the curve 41 and the curve 42 are substantially completely matched, so that the curves 41 and 42 are calibrated together, that is, the doppler shift is substantially equal to the frequency offset estimation value. When a curve fitted with a value obtained by changing the doppler shift with time has a "few" character or a rectangular wave character, the frequency offset estimation value also has the character. Therefore, in another embodiment of the present invention, the motion parameter value may be a frequency offset estimation value.

In a specific implementation, the first duration may be up to ten seconds, or an integer multiple of the ten seconds. As long as in the first duration, the time-varying curve of the motion parameter value of the terminal may be used to determine whether the motion parameter value matches at least one of the characteristic curves.

When it is determined that the curve matches a preset characteristic curve, S14 may be performed; otherwise, the flow may end.

S14: identifying that the terminal is in the high-speed rail environment.

In order to improve the communication quality of the terminal in the high-speed rail environment, in a specific implementation, after the terminal is determined to be in the high-speed rail environment, the terminal may be switched to a communication mode corresponding to the high-speed rail environment and kept for a preset second duration. And in order to adjust the communication mode of the terminal in time, the motion parameter value of the terminal can be continuously obtained within the second duration of the switching to the communication mode corresponding to the high-speed rail environment.

Since high-speed rail generally does not stay at a station for a long time, the second time period may be 20 or 30 minutes in one embodiment of the present invention. The second time period can also be set to other values according to actual needs by those skilled in the art.

In a specific implementation, if the curve is not matched with the preset characteristic curve within a preset third time period after the communication mode corresponding to the high-speed rail environment is switched to, the communication mode corresponding to the high-speed rail environment may be exited, so as to avoid interference to normal communication of the terminal. And the third duration is greater than the second duration.

In an embodiment of the present invention, the third time period may be 35 or 45 minutes. The third time period can be set to other values according to actual needs by those skilled in the art.

When the terminal is in a high-speed rail environment, the change of the motion parameter value of the terminal within a certain time length is matched with a specific curve, so that a curve of the motion parameter value of the terminal changing along with time is obtained through fitting, and when the curve conforms to the preset characteristic curve, the terminal is determined to be in the high-speed rail environment, namely, the terminal is identified to be in the high-speed rail environment through the change trend of the motion parameter value of the terminal, so that the situation that the motion environment of the terminal is identified by mistake or the motion environment where the terminal is located cannot be identified due to the fact that the motion speed of the terminal is detected improperly can be avoided, and the situation that the terminal is in the high-speed rail environment can be identified accurately.

in order to make those skilled in the art better understand and implement the present invention, the following provides an apparatus for terminal motion environment identification in the embodiment of the present invention, where the motion environment includes a high-speed rail environment, and as shown in fig. 5, the apparatus may include: an obtaining unit 51, a fitting unit 52, a judging unit 53 and a motion environment identifying unit 54, wherein:

The obtaining unit 51 is adapted to obtain a motion parameter value of the terminal within a preset first duration;

the fitting unit 52 is adapted to fit a curve of the motion parameter value of the terminal changing with time;

the judging unit 53 is adapted to judge whether the curve matches a preset characteristic curve; the preset characteristic curve corresponds to the high-speed rail environment;

The motion environment recognition unit 54 is adapted to recognize that the terminal is in the high-speed rail environment when the judging unit 53 determines that the curve matches a preset characteristic curve.

In a specific implementation, the motion parameter value may be various, such as a doppler frequency shift value, or a frequency offset estimation value.

in a specific implementation, the apparatus may further include: the switching unit 55 is adapted to switch to a communication mode corresponding to the high-speed rail environment and keep a preset second duration after the judging unit 53 determines that the terminal is located in the high-speed rail environment;

the obtaining unit 51 is further adapted to continue to obtain the motion parameter value of the terminal after switching to the communication mode corresponding to the high-speed rail environment.

In a specific implementation, the switching unit 55 is further adapted to, after switching to the communication mode corresponding to the high-speed rail environment, within a preset third time period, exit the communication mode corresponding to the high-speed rail environment when the curve does not match the preset characteristic curve; the third duration is greater than the second duration.

in a specific implementation, the preset characteristic curve is a curve in the shape of a rectangular wave, or may be a continuous curve in the shape of a zigzag.

In a specific implementation, each period of the characteristic curve comprises one peak and two troughs or one trough and two peaks.

In an embodiment of the present invention, the period may be ten seconds, that is, within a shortest ten seconds, a curve obtained by fitting the doppler shift of the terminal in a high-speed rail environment with the change of time may be matched with the "geometric" feature.

Those skilled in the art will appreciate that all or part of the steps in the methods of the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer-readable storage medium, and the storage medium may include: ROM, RAM, magnetic or optical disks, and the like.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.