METHOD FOR PREDICTING OUTDOOR THREE-DIMENSIONAL SPACE SIGNAL FIELD STRENGTH BY EXTENDED COST-231-WALFISCH-IKEGAMI PROPAGATION MODEL

Abstract

A method for predicting outdoor three-dimensional space signal field strength by extended COST-231-Walfisch-Ikegami propagation model, comprising: establishing a three-dimensional scene model between a transmitting base station and a predicted region space; performing an on-site measurement according to a certain resolution in a prediction region and recording wireless signal strength information at a height of 1 m above the ground; acquiring a vertical cross section between the transmitting base station and a receiving point at a height of 1 m above the ground, and acquiring therefrom an average roof height, an average street width and an average between-building space; predicting a reception signal strength at a measurement point in a calculation formula of a COST-231-Walfishch-Ikegami propagation model; correcting the COST-231-Walfishch-Ikegami propagation model of the measurement point according to an error between measured data and a prediction result; acquiring a vertical cross section between the transmitting base station and a receiving point at other height of the measurement point, and filtering therefrom buildings outside a Fresnel circle to re-acquire the average roof height, the average street width and the average between-building space; and calculating a reception signal strength at other height of the measurement point according to the corrected COST-231-Walfishch-Ikegami propagation model.

Claims

1. A method for predicting outdoor three-dimensional space signal field strength by an extended COST-231-Walfisch-Ikegami propagation model, comprising: (1) establishing a three-dimensional scene model from a transmitting base station to a predicted region space: using an existing modeling technology to establish a three-dimensional scene model from the transmitting base station and the predicted region space by importing GIS format map, the three-dimensional scene model comprises street information and three-dimensional building models of all buildings within a scope of the transmitting base station and a prediction region; wherein the buildings within the scope of the transmitting base station and the prediction region are determined as all buildings within a first Fresnel circle between the transmitting base station and receiving points of the prediction region; radius r of the first Fresnel circle is calculated by $r = \sqrt{\frac{.Math. .Math. d_{1} .Math. d_{2}}{d}},$ wherein is wavelength of electromagnetic wave, d represents distance from the transmitting base station to a receiving point, S represents an infinite plane that is perpendicular to a line connecting a transmitting point and a receiving point, and d.sub.1 and d.sub.2 represent distances between the transmitting base station and the plane S and between the receiving point and the plane S respectively; the three-dimensional building model information includes building outer envelope information, building height information h.sub.roof, and building geographical location information; and the street information includes street width information w, and street geographical location information; (2) measuring a wireless signal strength at a height of 1 m within the prediction region using existing instruments according to a fixed resolution to form measurement data (x, y, z, M.sub.rx) of each receiving point; the measurement data of each receiving point includes location information and wireless signal strength information of the receiving point, wherein x is longitude information of the receiving point, y is latitude information of the receiving point, z is height information of the receiving point, and M.sub.rx is reception signal strength; (3) predicting reception signal strength of a measurement point at a height of 1 m according to the COST-231-Walfisch-Ikegami propagation model; acquiring a vertical cross section between the transmitting base station and a measurement point at a height of 1 m above the ground, and acquiring therefrom key parameters of the COST-231-Walfisch-Ikegami propagation model, wherein the key parameters include an average roof height h.sub.roof, an average street width w, an average between-building space b, a base station height h.sub.tx, a receiving point height h.sub.rx, a base station transmitting power W, a base station transmitting signal frequency f, a distance d between the base station and the measurement point, and an angle between an incident direction of a base station direct wave and a direction of a street to which the measurement point belongs; predicting a reception signal strength T.sub.rx of the receiving point according to a calculation formula of the COST-231-Walfisch-Ikegami propagation model, comprising steps (3-1) to (3-3): (3-1): calculating propagation losses of line-of-sight propagation and non-line-of-sight propagation between the base station and a test point respectively, by calculating a propagation loss L.sub.blos of line-of-sight propagation in accordance with step (3-2) and calculating a propagation loss L.sub.bNlos of non-line-of-sight propagation in accordance with step (3-3), therefore propagation loss L.sub.b is represented as a following formula: $L_{b} = {\begin{matrix} L_{blos}, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. line - of - sight .Math. .Math. propagation .Math. .Math. from .Math. .Math. a .Math. \\ .Math. transmitting .Math. .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \\ L_{bNlos}, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. non - line - of - sight .Math. .Math. propagation .Math. .Math. from .Math. .Math. a .Math. \\ .Math. transmitting .Math. .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \end{matrix}$ (3-2): if there is line-of-sight propagation between the base station and the test point, the propagation loss is calculated by a formula L.sub.blos=42.6+26lgd+20lgf; (3-3): if there is non-line-of-sight propagation between the base station and the test point, the propagation loss is calculated by a formula L.sub.bNlos=L.sub.bs+L.sub.rts+L.sub.msd, wherein L.sub.bs is propagation loss of a free space, L.sub.rts is diffraction and scattering loss from the roof to the street, L.sub.msd is diffraction loss of multiple barriers, and L.sub.bs, L.sub.rts and L.sub.msd are calculated by a specific method including steps (3-3-1) to (3-3-3): (3-3-1): in step (3-3), L.sub.bs is calculated by a formula:
L.sub.bs32.45+20lgd+20lgf; (3-3-2): in step (3-3), L.sub.rts is calculated by a formula: $L_{rts} = {\begin{matrix} - 16.9 - 10 .Math. lgw + 10 .Math. lgf + 20 .Math. \lg (h_{roof} - h_{rx}) + L_{ori}, & when .Math. .Math. h_{roof} > h_{rx} \\ 0, & when .Math. .Math. L_{rts} < 0 \end{matrix}$ wherein $L_{ori} = {\begin{matrix} - 10 + 0.354 .Math. .Math., & 0 .Math. < 35 .Math. \\ 2.5 + 0.075 (- 35), & 35 .Math. < 55 .Math. \\ 4.0 - 0.114 (- 35), & 55 .Math. < 90 .Math. \end{matrix}$ (3-3-3): in step (3-3), L.sub.msd is calculated by a formula: $L_{msd} = {\begin{matrix} L_{bsh} + K_{a} + K_{d} .Math. lgd + K_{f} .Math. lgf - 9 .Math. lgb \\ 0, when .Math. .Math. L_{msd} < 0 \end{matrix}$ wherein, $.Math. L_{bsh} = {\begin{matrix} - 18 .Math. \lg (1 + h_{tx} - h_{roof}), & h_{tx} > h_{roof} \\ 0, & when .Math. .Math. h_{tx} h_{roof} \end{matrix} .Math. .Math. K_{a} = {\begin{matrix} 54, & h_{tx} > h_{roof} \\ 54 - 0.8 (h_{tx} - h_{roof}), & d 05 .Math. .Math. km .Math. .Math. and .Math. .Math. h_{tx} h_{roof} \\ 54 - 0.8 (h_{tx} - h_{roof}) (\frac{d}{0.5}), & d < 0.5 .Math. .Math. km .Math. .Math. and .Math. .Math. h_{tx} h_{roof} \end{matrix} .Math. .Math. .Math. K_{d} = {\begin{matrix} 18, & h_{tx} > h_{roof} \\ 18 - 15 (\frac{h_{tx} - h_{roof}}{h_{roof} - h_{rx}}), & h_{tx} h_{roof} \end{matrix} .Math. .Math. K_{f} = - 4 + {\begin{matrix} 0.7 (\frac{f}{925} - 1), & \begin{matrix} for .Math. .Math. a .Math. .Math. medium - sized .Math. .Math. city .Math. .Math. and .Math. .Math. a .Math. .Math. suburban \\ center .Math. .Math. having .Math. .Math. trees .Math. .Math. of .Math. .Math. medium .Math. .Math. density \end{matrix} \\ 1.5 (\frac{f}{925} - 1), & for .Math. .Math. center .Math. .Math. of .Math. .Math. a .Math. .Math. big .Math. .Math. city \end{matrix}$ (3-4) when there is line-of-sight propagation between the transmitting base station and the test point, the reception signal field strength of the test point is T.sub.los=WL.sub.blos; when there is non-line-of-sight propagation between the transmitting base station and the test point, the reception signal field strength of the test point is T.sub.Nlos=WL.sub.bNlos, therefore the signal field strength of the test point is represented as: $T_{rx} = {\begin{matrix} T_{los} = W - L_{blos}, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. line - of - sight .Math. .Math. propagation .Math. .Math. from .Math. .Math. a .Math. .Math. transmitting .Math. \\ .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \\ T_{Nlos} = W - L_{bNlos}, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. line - of - sight .Math. .Math. propagation .Math. .Math. from .Math. .Math. a .Math. .Math. .Math. transmitting .Math. \\ .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \end{matrix};$ (4) calculating an error =M.sub.rxT.sub.rx between a measured value and a predicted value according to the actually measured field strength M.sub.rx and a predicted field strength T.sub.rx of the test point, and correcting the calculation formula of the CO ST-231-Walfisch-Ikegami propagation model of the test point; (5) acquiring a vertical cross section between the transmitting base station and the receiving point at an extended height h.sub.rx of the test point, and filtering therefrom buildings outside the first Fresnel circle between the transmitting point and the receiving point, to re-acquire key parameters of the COST-231-Walfisch-Ikegami propagation model and calculating the reception signal strength at the extended height h.sub.rx according to the corrected COST-231-Walfisch-Ikegami propagation model; (6) changing height of h.sub.rx, repeating step (5), and calculating reception signal strength at all extended heights on the receiving point using an algorithm of the corrected COST-231-Walfisch-Ikegami propagation model; (7) changing the location of the test point, repeating steps (3) to (6), and calculating reception signal strength at all extended heights on all the test points to acquire a prediction signal field strength in a three-dimensional space of an outdoor area of a building within the prediction region.

2. The method for predicting outdoor three-dimensional space signal field strength by the extended COST-231-Walfisch-Ikegami propagation model according to claim 1, wherein a correction value between the actually measured field strength M.sub.rx and the predicted field strength T.sub.rx in step (4) includes a corrected value .sub.los of line-of-sight propagation and a corrected value .sub.Nlos of non-line-of-sight propagation: $= M_{rx} - T_{rx} = {\begin{matrix} _{los} = M_{rx} - T_{los}, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. line - of - sight .Math. .Math. \\ .Math. propagation .Math. .Math. from .Math. .Math. a .Math. .Math. transmitting .Math. .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \\ _{Nlos} = M_{rx} - T_{Nlos}, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. non - line - of - sight .Math. .Math. \\ .Math. propagation .Math. .Math. from .Math. .Math. a .Math. .Math. .Math. transmitting .Math. .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \end{matrix}$

3. The method for predicting outdoor three-dimensional space signal field strength by the extended COST-231-Walfisch-Ikegami propagation model according to claim 1, wherein step (5) comprises calculating the reception signal strength at the extended height h.sub.rx of the test point in step (3) using the calculation formula of the corrected COST-231-Walfisch-Ikegami propagation model in step (4), including steps (5-1) to (5-2): (5-1) acquiring a vertical cross section between the transmitting base station and the extended height h.sub.rx of the test point, and filtering therefrom buildings outside the first Fresnel circle between the transmitting point and the receiving point, a calculation method of the radius r of the first Fresnel circle is the same as that of the step (1), $r = \sqrt{\frac{.Math. .Math. d_{1} .Math. d_{2}}{d}},$ wherein, d represents distance from the transmitting base station to the receiving point, S represents the infinite plane that is perpendicular to the line connecting the transmitting point and the receiving point, d.sub.1 and d.sub.2 represent distance between the transmitting base station and the plane S and between the receiving point and the plane S respectively, the first Fresnel radius is a radius of a circle that is formed by intersecting the plane S and a Fresnel ellipsoid; (5-2) re-acquiring key parameters of the COST-231-Walfisch-Ikegami propagation model according to three-dimensional building and street information after filtered out the first Fresnel circle, calculating field strength T.sub.rx of the receiving point using the formula of the step (3), and correcting the receiving point signal field strength using a correction parameter calculated in the step (4), and the corrected receiving point field strength is represented as T.sub.rx=T.sub.rx+.

4. The method for predicting outdoor three-dimensional space signal field strength by the extended COST-231-Walfisch-Ikegami propagation model according to claim 1, wherein step (6) comprises changing a value of h.sub.rx at a height interval according to a predicted resolution; repeating calculation procedure of step (5) to calculate prediction results at all extended heights from 1 m to 2h.sub.tx: applying a mirror principle extended model algorithm when the calculated height h.sub.rx>h.sub.tx and there is non-line-of-sight propagation, and replacing actual height h.sub.rx with a mirrored height h.sub.rx when the COST-231-Walfishch-Ikegami propagation model formula is applied, wherein the mirrored height conforms to formula $h_{rx}^{} = {\begin{matrix} 2 .Math. h_{tx} - h_{rx}^{}, & when .Math. .Math. h_{rx}^{} > h_{tx} \\ h_{rx}^{}, & when .Math. .Math. h_{rx}^{} h_{tx} \end{matrix} .$

5. A method for predicting outdoor three-dimensional space signal field strength by extended COST-231-Walfisch-Ikegami propagation model, comprising: establishing a three-dimensional scene model from the transmitting base station to the predicted region space; performing an on-site measurement according to a certain resolution in a prediction region and recording wireless signal strength information at a height of 1 m above the ground; acquiring a vertical cross section between the transmitting base station and a receiving point at a height of 1 m above the ground, and acquiring therefrom an average roof height, an average street width and an average between-building space; predicting a reception signal strength at a measurement point in a calculation formula of a COST-231-Walfishch-Ikegami propagation model; correcting the COST-231-Walfishch-Ikegami propagation model of the measurement point according to an error between measured data and a prediction result; acquiring a vertical cross section between the transmitting base station and a receiving point at other height of the measurement point, and filtering therefrom buildings outside a Fresnel circle to re-acquire the average roof height, the average street width and the average between-building space; and calculating a reception signal strength at other height of the measurement point according to the corrected COST-231-Walfishch-Ikegami propagation model.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 is a flowchart of a predicting outdoor three-dimensional space signal field strength by an extended COST-231-Walfisch-Ikegami propagation model according to the invention;

[0045] FIG. 2 illustrates a vertical cross section and model parameters of COST-231-Walfisch-Ikegami propagation model according to the invention;

[0046] FIG. 3 illustrates an angle between an incident direction of a base station direct wave and a direction of a street to which a test point belongs according to the invention;

[0047] FIG. 4 is a schematic diagram of Fresnel circle filtered buildings according to the invention;

[0048] FIG. 5 is a mirror image schematic diagram according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0049] The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art.

[0050] The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0051] Hereinafter the invention is further described with reference to the accompanying figures and embodiment, but the invention is not limited thereto.

[0052] As shown in FIGS. 1-5.

EMBODIMENT

[0053] An extended COST-231-Walfisch-Ikegami propagation model predicts the field strength generated by an outdoor base station antenna around a building in a center region of a big city.

[0054] (1) Establishing a three-dimensional scene model from a transmitting base station to a predicted region space:

[0055] according to the given 5 m-accuracy GIS map information of Luohu, Shenzhen, establishing a three-dimensional scene model between a transmitting base station and a predicted region space, wherein the three-dimensional scene model comprises street information and three-dimensional building models of all buildings within a scope of the transmitting base station and the prediction region; all buildings within the scope of the transmitting base station and the prediction region are determined as all buildings within a first Fresnel circle between the transmitting base station and receiving points of the prediction region; radius r of the first Fresnel circle is calculated by

[00011] $r = \sqrt{\frac{.Math. .Math. d_{1} .Math. d_{2}}{d}},$

wherein a represents distance between the transmitting base station and a receiving point d=600 m, S represents an infinite plane that is perpendicular to a line connecting a transmitting point and a receiving point, d.sub.1 and d.sub.2 represent distance between the transmitting base station and the plane S and between the receiving point and the plane S respectively, d.sub.1+d.sub.2=600 m, is wavelength of electromagnetic wave, a frequency f of the electromagnetic wave is 2600 MHz, propagation velocity of the electromagnetic wave is velocity of light c, =c/f=3/26 m, a first Fresnel radius is a radius of a circle that is formed by intersecting the plane S and a Fresnel ellipsoid, therefore Fresnel radius in the center of the ellipsoid is

[00012] $r = \sqrt{\frac{.Math. .Math. d_{1} .Math. d_{2}}{d}} = \sqrt{\frac{3 300 300}{26 600}} = 4.16 .Math. .Math. m;$

the three-dimensional building model information includes building outer envelope information, building height information, and building geographical location information; and the street information includes street width information w, and street geographical location information;

[0056] (2) selecting streets around a building as a prediction region, and measuring a wireless signal strength at a height of 1 m within the prediction region using the existing instruments according to a resolution of 5 m to form measurement data (x, y, z, M.sub.rx) of each receiving point:

[0057] the measurement data of each receiving point includes location information and wireless signal strength information of the receiving point, wherein x is longitude information of the receiving point, y is latitude information of the receiving point, z is height information of the receiving point, and M.sub.rx is actual reception signal strength;

[0058] (3) selecting a receiving point P, and acquiring the key parameters of the COST-231-Walfisch-Ikegami propagation model according to a vertical cross section between the transmitting base station and the receiving point, wherein the key parameters include an average roof hight h.sub.roof=30 m, an average street width w=14 m, an average between-building space b=100 m, a base station height h.sub.tx=39 m, a receiving point height h.sub.rx=1 m, a base station transmitting power W=49.63 dBm, a base station transmitting signal frequency f=2600 MHz, a distance from the base station to the receiving point d=0.6 km, and an angle between an incident direction of a base station direct wave and a direction of a street to which a test point belongs (p=37.5;

[0059] (3-1) calculating propagation losses of line-of-sight propagation and non-line-of-sight propagation between the base station and the receiving point respectively, by calculating a propagation loss L.sub.blos of line-of-sight propagation in accordance with step (3-2) and calculating a propagation loss L.sub.bNlos of non-line-of-sight propagation in accordance with step (3-3), therefore propagation loss L.sub.b is represented as a following formula:

[0060] (3-2) if P is line-of-sight propagation, then propagation loss is calculated by a formula: L.sub.blos=42.6+26lgd+20lgf=42.6+26*lg0.6+20*lg2600=105.13 dB;

[0061] (3-3) if P is non-line-of-sight propagation, then propagation loss is calculated according to a formula L.sub.bNlos=L.sub.bs+L.sub.rts+L.sub.msd, wherein L.sub.bs is propagation loss of a free space, L.sub.rts is diffraction and scattering loss from the roof to the street, L.sub.msd is diffraction loss of multiple barriers, and L.sub.bs, L.sub.rts and L.sub.msd are calculated by a specific method including steps (3-3-1) to (3-3-3):

[0062] (3-3-1): L.sub.bs is calculated by a formula:

L.sub.bs=32.45+20lgd+20lgf=32.45+20lg0.6+20lg2600=96.3.

[0063] (3-3-2): L.sub.rts is calculated by a formula:

[00013] $\begin{matrix} L_{rts} = .Math. - 16.9 - 10 .Math. lgw + 10 .Math. lgf + 20 .Math. \lg (h_{roof} - h_{rx}) + L_{ori} \\ = .Math. - 16.9 - 10 .Math. \lg .Math. .Math. 14 + 10 .Math. \lg .Math. .Math. 2600 + 20 .Math. \lg (30 - 1) + L_{ori} \end{matrix}$
wherein, L.sub.ori=2.5+0.075(35)=2.5+0.075(37.535)=2.64

thus L.sub.rts=37.7;

[0064] (3-3-3): L.sub.msd is calculated by a formula:

[00014] $\begin{matrix} L_{msd} = .Math. L_{bsh} + Ka + K_{d} .Math. lgd + K_{f} .Math. lgf - 9 .Math. lgb \\ = .Math. L_{bsh} + K_{a} + K_{d} .Math. \lg .Math. .Math. 0.6 + K_{f} .Math. \lg .Math. .Math. 2600 - 9 .Math. \lg .Math. .Math. 100 \end{matrix}$

[0065] wherein,

L.sub.bsh=18lg(1+h.sub.txh.sub.roof)=18lg(1+9)=18

Ka=54

Kd=18

[00015] $K_{f} = - 4 + 1.5 (\frac{f}{925} - 1) = - 4 + 1.5 (\frac{2600}{925} - 1) = - 1.28$
thus L.sub.msd=18+54+18lg0.61.28lg26009lg100=9.62

L.sub.bNlos=L.sub.bs+L.sub.rts+L.sub.msd=96.3+37.7+9.62=143.66

[0066] (3-4): the receiving point signal field strength is calculated according to a following formula:

[00016] $T_{rx} = {\begin{matrix} T_{los} = W - L_{blos} = - 55.5 .Math. .Math. dBm, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. line - of - sight \\ propagation .Math. .Math. from .Math. .Math. a .Math. .Math. transmitting .Math. .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \\ T_{Nlos} = W - L_{bNlos} = - 94.03 .Math. .Math. dBm, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. non - line - of - sight \\ propagation .Math. .Math. from .Math. .Math. a .Math. .Math. transmitting .Math. .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \end{matrix}$

[0067] (4) measurement data according to the test position, M=98.5 dBm,

[00017] $= {\begin{matrix} _{los} = M_{rx} - T_{los} = - 43 .Math. .Math. dBm, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. line - of - sight \\ propagation .Math. .Math. from .Math. .Math. a .Math. .Math. transmitting .Math. .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \\ _{Nlos} = M_{rx} - L_{Nlos} = - 4.47 .Math. .Math. dBm, & \begin{matrix} when .Math. .Math. there .Math. .Math. is .Math. .Math. non - line - of - sight \\ propagation .Math. .Math. from .Math. .Math. a .Math. .Math. transmitting .Math. .Math. point .Math. .Math. to .Math. .Math. a .Math. .Math. receiving .Math. .Math. point \end{matrix} \end{matrix}$

[0068] (5) acquiring a vertical cross section between the transmitting base station and the receiving point at an extended height h.sub.rx=4 m of the measurement point P, filtering therefrom buildings outside the first Fresnel circle between the transmitting point and the receiving point, and it is judged that there is non-line-of-sight propagation between the transmitting point and the receiving point, thus maintaining an average roof height h.sub.roof=30 m, an average street width w=14 m, an average between-building space b=100 m, a base station height h.sub.tx=39 m, a receiving point height h.sub.rx=4 m, a base station signal transmitting power W=49.63 dBm, a base station transmitting signal frequency f=2600 MHz, a distance from the base station to the reception pint d=0.6 km, and an angle between an incident direction of a base station direct wave and a direction of a street to which a test point belongs =37.5. T.sub.rx=93.08 is calculated using steps (3-1) to (3-5);

[0069] The reception signal strength T.sub.rx at the extended height h.sub.rx of the measurement point is calculated according to the corrected COST-231-Walfisch-Ikegami propagation model. T.sub.rx=T.sub.rx+=93.084.47=97.55 dBm;

[0070] (6) at an interval of 3 m, changing the heights of h.sub.rx (h.sub.rxh.sub.tx) into (7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37) m, respectively, filtering buildings outside the first Fresnel circle between the transmitting point and the receiving point; if it is determined that there is still non-line-of-sight propagation between the transmitting point and the receiving point, then the average roof heights h.sub.roof are (30, 30, 30, 30, 33.75, 33.75, 33.75, 38, 38, 38, 38) m, respectively, the average street widths w are (14, 14, 14, 14, 16.8, 16.8, 16.8, 21, 21, 21, 21) m, respectively, the average betweenbuilding spaces b are (100, 100, 100, 100, 120, 120, 120, 150, 150, 150, 150) m, respectively, the distances d between the base station and the receiving point are (0.6, 0.6, 0.599, 0.599, 0.599, 0.599, 0.599, 0.599, 0.599, 0.599, 0.599) km, respectively, the base station signal transmitting power W=49.63 dBm, the base station transmitting signal frequency f=2600 MHz, and the angle between the incident direction of the base station direct wave and the direction of the street to which the test point belongs =37.5; [0071] repeating step (5), reception signal strength at all extended heights on the receiving point are calculated as (96.49, 95.25, 93.83, 92.14, 94.77, 92.79, 90.23, 98.46, 95.36, 90.5, 78.46) dBm, respectively using an algorithm of the corrected COST-231-Walfisch-Ikegami propagation model;

[0072] when the heights of h.sub.rx are further extended to (40, 43), h.sub.rx>h.sub.tx, buildings outside the first Fresnel circle are filtered according to the cross section between the transmitting point and the receiving point, and it is determined that there is still non-line-of-sight propagation between the transmitting point and the receiving point; in that case, mirror image heights are calculated as (38, 35) m, respectively, according to mirror image principle h.sub.rx=2h.sub.txh.sub.rx; in that case, h.sub.roof are (38, 48) m respectively, w are (21, 28) m respectively, b are (150, 200) m respectively, d are (0.599, 0.599) km respectively, the base signal transmitting power W=49.63 dBm, the base station transmitting signal frequency f=2600 MHz, and the angle between the incident direction of the base station direct wave and the direction of the street to which the test point belongs =37.5; [0073] repeating step (5), reception signal strength at all extended heights on the receiving point are calculated as (71.74, 95.61) dBm, respectively using an algorithm of the corrected COST-231-Walfisch-Ikegami propagation model; when the heights of h.sub.rx are further extended to (46, 49, 52, 55, 58, 61, 64, 67, 70, 73, 76) m, buildings outside the first Fresnel circle are filtered according to the cross section between the transmitting point and the receiving point, and it is judged that there is line-of-sight propagation between the transmitting point and the receiving point; the distances d between the base station and the receiving point are (0.599, 0.599, 0.599, 0.599, 0.599, 0.599, 0.599, 0.6, 0.6, 0.6, 0.6) km respectively, the base signal transmitting power W=49.63 dBm, and the base station transmitting signal frequency f=2600 MHz; repeating step (5), reception signal strength at all extended heights on the receiving point are calculated as (98.48, 98.48, 98.48, 98.48, 98.48, 98.48, 98.48, 98.5, 98.5, 98.5, 98.5) dBm, respectively using the corrected COST-231-Walfisch-Ikegami propagation model formula;

[0074] (7) selecting other test points, and repeating steps (3) to (6) to calculate the signal field strength of the three-dimensional space.

[0075] The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

METHOD FOR PREDICTING OUTDOOR THREE-DIMENSIONAL SPACE SIGNAL FIELD STRENGTH BY EXTENDED COST-231-WALFISCH-IKEGAMI PROPAGATION MODEL

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Cpc classification

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H04B17/3913

ELECTRICITY

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H04W16/18

ELECTRICITY

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H04B17/3912

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G01S5/02523

PHYSICS

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H04W24/06

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H04B17/318

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H04B17/373

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H04W16/22

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H04B17/391

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H04B17/373

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G01S5/02

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H04W16/18

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H04W24/06

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Abstract

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