加速多镜像法对非规则城市环境电磁辐射的分析计算
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摘要
在当今飞速发展的信息时代，广播、电视、通信是发展最快的产业之一，而移动通信更是渗入到千百万人们的日常生活当中。为满足不断增长的移动通信话务需要，要求增加城市环境的微蜂窝小区通信的覆盖范围。同时为保证人们的健康生活环境，控制或杜绝包括电磁辐射污染在内的各种污染，是人们目前所面临的重要课题。在对现有电磁辐射源（如移动通信基站、广播电视发射天线等）环境电磁污染状况进行评估时可以进行实地测试，但是对在建或拟建的辐射源则不可能进行先测试，同时为了避免实地测试的费时、费力和较大的测试费用，通过计算机来计算分析城市环境电波传播显得很有必要。
电波传播预测的研究已有30多年，这些预测研究多采用大区模型，随着近几年移动通信的飞速发展，自然而然从大区模型转到微小区模型。现有模型中，射线追踪法的计算结果较为准确。在各种文献资料中，对建筑物规则排列分布的城市环境的电波传播预测较多，而对建筑物非规则排列分布的城市环境的电波传播预测则很少见。
本文研究并给出了一种非规则城市环境电波传播的预测方法——加速多镜像法。镜像法是基于点对点的射线追踪法，所以计算结果精度较高。对于建筑物墙面是平面的情况，用多镜像法是可行的，但当建筑物不是矩形（是多面体），并且排列不是平行对齐时，遮挡测试和镜像源找寻就比较复杂，计算量大。为提高计算效率，本方法采用了射线加速技术，包括背面采集、二元空间分区算法和降维处理。这些算法使得相交测试数量大大减少，计算量也相应大大减少，节省了CPU时间，提高了分析计算速度。本方法先建立镜像树——各级镜像源及其可视面和可视绕射边缘的树形数据结构，然后按照同样方法建立只有一层的场树——场点的可视面和可视绕射边缘的树形数据结构，遍历镜像树并查询场树就可找出所有到达场点的射线，从而求出场点的电场强度值和路径损耗。输入发射源坐标和各种特性，建筑物坐标和各种特性，就可以求出区域范围内给定观察点的电场强度值和路径损耗。
本文计算了一种典型的规则排列城市环境中街道的电波传播路径损耗，并与文献中实测及计算数据比较，然后对一种非规则城市环境的电波传播特性进行了分析计算。最后给出了一个该环境的电波传播预测应用例子。
The communication is the industry which is developing the most rapidly in the information age. Thousands upon thousands of people are getting close touch with the mobile communication in their daily life. For fulfilling the request for the increasing mobile communication, it requires increasing the cover area of microcell mobile communication system.
To keep the environment people live in, we should restrict or prevent many kinds of pollution, which includes electromagnetic radiation pollution.
While we are considering setting up base station or evaluating the electromagnetism pollution of environment, we can measure on the spot. To save time, hard work and cost taken by measuring on spot, it is necessary to calculate and analyze the electromagnetic wave propagation in urban area.
The research of electromagnetic wave propagation prediction has had 30 many years. And along with the development of mobile communication, the prediction model of large area turns to the prediction model of microcells area naturally. Of the available models, the computational results of ray tracing method are comparatively accurate.
In the various document data more electromagnetic wave propagation forecasts aimed at the urban area that the buildings were regularly arranged and the detailed datum that the forecasts aimed at the urban area that the buildings were regular arranged were not seen.
A kind of method - accelerative multi-images method is given to the electromagnetic wave propagation prediction to the irregular urban area of this article. Because the mirror image method is basing on the point-to-point ray tracing method, the computational solution precision is higher.
As for the building wall face is the plane, it is feasible to use multi-mirror images method. But when the building is not only the rectangle (being the polyhedron) and the buildings is not merely justified parallel, sheltering tests and mirror image source's finding are fairly more complicatedly, and the calculation amount is great.
For raising the capacity, this method has used the ray acceleration technology, including that the back gathers and the partition algorithm in binary space and decreasing dimensions.
These algorithms make the intersection test quantity reduces greatly, and calculation capacity is corresponding and reduces greatly, and has economized CPU's time.
This method is first to establish the mirror image tree - tree shape data structure includes all levels mirror image sources and their visible facets and diffractive edges, then according to same method to establish the field tree of only one layer- tree shape data structure includes the field point's (observation point) visible facets and diffractive edges, then by the traversal of mirror image tree and inquiring about field tree we can find out all rays arrive field point. Thus we can calculate the electric field intensity value and the path loss.
Input radiant point's coordinate and various property, building's coordinate and various property, we can calculate the given field point's electric field intensity value and the path loss.
This text has counted the electric wave propagation path loss of street in one kind of typical rule range urban area, and reaches calculation data fairly with the measured data in the document. Then calculate and analyze electric wave propagation's characteristic in urban area. Finally give an electric wave propagation prediction application example of this model.
电波传播预测的研究已有30多年，这些预测研究多采用大区模型，随着近几年移动通信的飞速发展，自然而然从大区模型转到微小区模型。现有模型中，射线追踪法的计算结果较为准确。在各种文献资料中，对建筑物规则排列分布的城市环境的电波传播预测较多，而对建筑物非规则排列分布的城市环境的电波传播预测则很少见。
本文研究并给出了一种非规则城市环境电波传播的预测方法——加速多镜像法。镜像法是基于点对点的射线追踪法，所以计算结果精度较高。对于建筑物墙面是平面的情况，用多镜像法是可行的，但当建筑物不是矩形（是多面体），并且排列不是平行对齐时，遮挡测试和镜像源找寻就比较复杂，计算量大。为提高计算效率，本方法采用了射线加速技术，包括背面采集、二元空间分区算法和降维处理。这些算法使得相交测试数量大大减少，计算量也相应大大减少，节省了CPU时间，提高了分析计算速度。本方法先建立镜像树——各级镜像源及其可视面和可视绕射边缘的树形数据结构，然后按照同样方法建立只有一层的场树——场点的可视面和可视绕射边缘的树形数据结构，遍历镜像树并查询场树就可找出所有到达场点的射线，从而求出场点的电场强度值和路径损耗。输入发射源坐标和各种特性，建筑物坐标和各种特性，就可以求出区域范围内给定观察点的电场强度值和路径损耗。
本文计算了一种典型的规则排列城市环境中街道的电波传播路径损耗，并与文献中实测及计算数据比较，然后对一种非规则城市环境的电波传播特性进行了分析计算。最后给出了一个该环境的电波传播预测应用例子。
The communication is the industry which is developing the most rapidly in the information age. Thousands upon thousands of people are getting close touch with the mobile communication in their daily life. For fulfilling the request for the increasing mobile communication, it requires increasing the cover area of microcell mobile communication system.
To keep the environment people live in, we should restrict or prevent many kinds of pollution, which includes electromagnetic radiation pollution.
While we are considering setting up base station or evaluating the electromagnetism pollution of environment, we can measure on the spot. To save time, hard work and cost taken by measuring on spot, it is necessary to calculate and analyze the electromagnetic wave propagation in urban area.
The research of electromagnetic wave propagation prediction has had 30 many years. And along with the development of mobile communication, the prediction model of large area turns to the prediction model of microcells area naturally. Of the available models, the computational results of ray tracing method are comparatively accurate.
In the various document data more electromagnetic wave propagation forecasts aimed at the urban area that the buildings were regularly arranged and the detailed datum that the forecasts aimed at the urban area that the buildings were regular arranged were not seen.
A kind of method - accelerative multi-images method is given to the electromagnetic wave propagation prediction to the irregular urban area of this article. Because the mirror image method is basing on the point-to-point ray tracing method, the computational solution precision is higher.
As for the building wall face is the plane, it is feasible to use multi-mirror images method. But when the building is not only the rectangle (being the polyhedron) and the buildings is not merely justified parallel, sheltering tests and mirror image source's finding are fairly more complicatedly, and the calculation amount is great.
For raising the capacity, this method has used the ray acceleration technology, including that the back gathers and the partition algorithm in binary space and decreasing dimensions.
These algorithms make the intersection test quantity reduces greatly, and calculation capacity is corresponding and reduces greatly, and has economized CPU's time.
This method is first to establish the mirror image tree - tree shape data structure includes all levels mirror image sources and their visible facets and diffractive edges, then according to same method to establish the field tree of only one layer- tree shape data structure includes the field point's (observation point) visible facets and diffractive edges, then by the traversal of mirror image tree and inquiring about field tree we can find out all rays arrive field point. Thus we can calculate the electric field intensity value and the path loss.
Input radiant point's coordinate and various property, building's coordinate and various property, we can calculate the given field point's electric field intensity value and the path loss.
This text has counted the electric wave propagation path loss of street in one kind of typical rule range urban area, and reaches calculation data fairly with the measured data in the document. Then calculate and analyze electric wave propagation's characteristic in urban area. Finally give an electric wave propagation prediction application example of this model.
引文
[1] Hata M.Empirical Formura for Propagation Loss in Land Mobile Radio Services.IEEE Trans.On Vehicular Technology,1980,VT-29: 317~325
[2] 腾本共荣，J.R.詹姆斯.移动天线系统手册（扬可忠，井淑华译）.北京：人民邮电出版社，1999.28~30
[3] Atefi.A,J.D.Parsons.Urban Radio Propagation in Mobile Radio Frequency Bands.Proc.Comms 86,Birmingham,UK,IEE Conference Publication No.262:13~18
[4] Ibrahim,J.D. Parsons.Single Strength Prediction in Built-Up Area.IEE proc,1983,vol.130,Part F,NO.5: 377~384
[5] J.D.Parsons.The Mobile Radio Propagation Channel.London: Pentech Press,1992
[6] M.F.Catedra,J.Perez-Arriaga.Cell planning for Wireless Communications.London:Artech House,1999
[7] A.J.Rustako,N.Amitay,etc.Radio Propagation at Microwave Frequencies for Lin-of-Sight Microcellular Mobile and personal Communications.IEEE Trans.On VehicularTechnology,1991,Vol.40: 203~210
[8] N.Blaunstein,M.Levin.VHF/UHF Wave Attenuation in a City With Regularly Spaced Buildings.Radio Science,1996,Vol.31,NO.2: 313~323
[9] N.Blaunstein, R.Giladi.Characteristics' Prediction in Urban and Suburban Envirinments.IEEE Trans.On vehicular Technology,1998,Vol.47,NO.1:225~234
[10] S.Y.Tan , H.S.Tan. UTD Propagation Model in an Urban Street Scene for Microcellular Communications. IEEE Trans. On Electromagnetic Compatibility, 1993,Vol.35, No.4: 423~428
[11] S.Y.Tan , H.S.Tan. A Theory for Propagation Path-Loss Characteristics in a City-Street Grid.IEEE Trans. On Electromagnetic Compatibility , 1995,Vol. 37, No.3: 333~342
[12] S.Y.Tan, H.S.Tan. Propagation Model for Microcellular Communications Applied to Path Loss Measurements in Ottawa City Streets. IEEE Trans. On Vehicular Technology, 1995,Vol.44, No.2: 313~317
[13] 吴剑锋，曹伟， 程勇 . 用射线跟踪法研究毫米波在微蜂窝中的传播特性. 南京邮电学院学报（自然科学版）， 2001, 21卷第三期:33～37
[14] 陈其科.城市环境电磁辐射的计算机分析：[硕士学位论文]，成都：电子科技大学，2001
[15] 李彤，娄媚等.利用射线跟踪方法进行微蜂窝电波传播预测.通信学报，1997，第18卷第11期：1～7
[16]卞国东,黄健.城市微小区电波预测.东南大学学报,1996.11 第26卷第6A期 ：13～19
[17] Hae-Won son, Noh-hoon Myung. A Deterministic ray Tube Method for Microcellular Wave Propagation Prediction Model. IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 1999,VOL.47, NO.8
[18] 种衍文,谢树果等。一种新的射线跟踪方法——三区分划处理法. 电波科学学报 ，2001 ，第16卷第二期：222～226
[19] 唐奡,龚克.一组电波传播环境描述参数的提出及应用. 电波科学学报，2001,第16卷第二期
[20] Athanasios G. Kanatas, Ioannis D. Kountouris, et al. A UTD Propagation Model in Urban Microcellular Environments. IEEE Trans. Veh. Technol., vol. 46, pp. 508-517, Feb. 1997.
[21] 阮颖铮.复射线理论及其应用 .成都：成都电讯工程学院出版社 ，1989
[22] 汪茂光.几何绕射理论 .西安：西北电讯工程学院出版社，1985
[23] Fumio Ikegami, Susumu Yoshida.Analysis of Multipath Propagation Structure in Urban Mobile Radio Environments. IEEE Trans. One AP, 1980, Vol.AP-28, No.4:531~537
[24] Kurt R.Schaubach, Nathaniel J.Davis. IV Microcellular Radio-Channel Porpagation Prediction.IEEE Antennas and Porpogation Magazine, 1994,Vol.36, No.4
[25] Hirofumi Suzuki. A Statistical Modal for Urban Radio Propagation.IEEE Trans. On Communication, 1977,Vol. COM-25, No.7, July
[26] Raymond J. Luebbers. A Heuristic UTD Slope Diffraction Coefficient for Rough Lossy Wedges. IEEE Trans. On AP, 1989,Vol. 37, No.2: 206~211
[27] George L. Turin, Fred D. Clapp, ect. A Statistical Modal of Urban Multipath Propagation.IEEE Trans. On Vehicular Technology, 1972, Vol. VT-21, No.1: 1~8
[28] M.F.Catedra, J.Perez, F.Saez de Adana.Efficient Ray-Tracing Techniques for Three－Dimensional Analyses of Propagation in Mobile Communications: Application to Picocell and Micorcell Scenarios. IEEE Antennas and Porpagation Magazine, 1998,Vol.40, No.2: 15~27
[29] Vinko Erceg, Saeed Ghassemzadeh, ect. Urban/Suburban Out_of_Sight Propagation Modeling.IEEE Communications Magazine, 1992:56~61
[30] 楼仁海，符果行，袁敬闳.电磁理论.成都：电子科技大学出版社，1996
[31] 殷人昆，陶永雷等.数据结构.北京:清华大学出版社，1999
[32] 官章全，唐晓卫.Visual C++ 6.0编程实例详解.北京：电子工业出版社，1999
[33] 钱能. C++程序设计教程.北京：清华大学出版社，2000
[2] 腾本共荣，J.R.詹姆斯.移动天线系统手册（扬可忠，井淑华译）.北京：人民邮电出版社，1999.28~30
[3] Atefi.A,J.D.Parsons.Urban Radio Propagation in Mobile Radio Frequency Bands.Proc.Comms 86,Birmingham,UK,IEE Conference Publication No.262:13~18
[4] Ibrahim,J.D. Parsons.Single Strength Prediction in Built-Up Area.IEE proc,1983,vol.130,Part F,NO.5: 377~384
[5] J.D.Parsons.The Mobile Radio Propagation Channel.London: Pentech Press,1992
[6] M.F.Catedra,J.Perez-Arriaga.Cell planning for Wireless Communications.London:Artech House,1999
[7] A.J.Rustako,N.Amitay,etc.Radio Propagation at Microwave Frequencies for Lin-of-Sight Microcellular Mobile and personal Communications.IEEE Trans.On VehicularTechnology,1991,Vol.40: 203~210
[8] N.Blaunstein,M.Levin.VHF/UHF Wave Attenuation in a City With Regularly Spaced Buildings.Radio Science,1996,Vol.31,NO.2: 313~323
[9] N.Blaunstein, R.Giladi.Characteristics' Prediction in Urban and Suburban Envirinments.IEEE Trans.On vehicular Technology,1998,Vol.47,NO.1:225~234
[10] S.Y.Tan , H.S.Tan. UTD Propagation Model in an Urban Street Scene for Microcellular Communications. IEEE Trans. On Electromagnetic Compatibility, 1993,Vol.35, No.4: 423~428
[11] S.Y.Tan , H.S.Tan. A Theory for Propagation Path-Loss Characteristics in a City-Street Grid.IEEE Trans. On Electromagnetic Compatibility , 1995,Vol. 37, No.3: 333~342
[12] S.Y.Tan, H.S.Tan. Propagation Model for Microcellular Communications Applied to Path Loss Measurements in Ottawa City Streets. IEEE Trans. On Vehicular Technology, 1995,Vol.44, No.2: 313~317
[13] 吴剑锋，曹伟， 程勇 . 用射线跟踪法研究毫米波在微蜂窝中的传播特性. 南京邮电学院学报（自然科学版）， 2001, 21卷第三期:33～37
[14] 陈其科.城市环境电磁辐射的计算机分析：[硕士学位论文]，成都：电子科技大学，2001
[15] 李彤，娄媚等.利用射线跟踪方法进行微蜂窝电波传播预测.通信学报，1997，第18卷第11期：1～7
[16]卞国东,黄健.城市微小区电波预测.东南大学学报,1996.11 第26卷第6A期 ：13～19
[17] Hae-Won son, Noh-hoon Myung. A Deterministic ray Tube Method for Microcellular Wave Propagation Prediction Model. IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 1999,VOL.47, NO.8
[18] 种衍文,谢树果等。一种新的射线跟踪方法——三区分划处理法. 电波科学学报 ，2001 ，第16卷第二期：222～226
[19] 唐奡,龚克.一组电波传播环境描述参数的提出及应用. 电波科学学报，2001,第16卷第二期
[20] Athanasios G. Kanatas, Ioannis D. Kountouris, et al. A UTD Propagation Model in Urban Microcellular Environments. IEEE Trans. Veh. Technol., vol. 46, pp. 508-517, Feb. 1997.
[21] 阮颖铮.复射线理论及其应用 .成都：成都电讯工程学院出版社 ，1989
[22] 汪茂光.几何绕射理论 .西安：西北电讯工程学院出版社，1985
[23] Fumio Ikegami, Susumu Yoshida.Analysis of Multipath Propagation Structure in Urban Mobile Radio Environments. IEEE Trans. One AP, 1980, Vol.AP-28, No.4:531~537
[24] Kurt R.Schaubach, Nathaniel J.Davis. IV Microcellular Radio-Channel Porpagation Prediction.IEEE Antennas and Porpogation Magazine, 1994,Vol.36, No.4
[25] Hirofumi Suzuki. A Statistical Modal for Urban Radio Propagation.IEEE Trans. On Communication, 1977,Vol. COM-25, No.7, July
[26] Raymond J. Luebbers. A Heuristic UTD Slope Diffraction Coefficient for Rough Lossy Wedges. IEEE Trans. On AP, 1989,Vol. 37, No.2: 206~211
[27] George L. Turin, Fred D. Clapp, ect. A Statistical Modal of Urban Multipath Propagation.IEEE Trans. On Vehicular Technology, 1972, Vol. VT-21, No.1: 1~8
[28] M.F.Catedra, J.Perez, F.Saez de Adana.Efficient Ray-Tracing Techniques for Three－Dimensional Analyses of Propagation in Mobile Communications: Application to Picocell and Micorcell Scenarios. IEEE Antennas and Porpagation Magazine, 1998,Vol.40, No.2: 15~27
[29] Vinko Erceg, Saeed Ghassemzadeh, ect. Urban/Suburban Out_of_Sight Propagation Modeling.IEEE Communications Magazine, 1992:56~61
[30] 楼仁海，符果行，袁敬闳.电磁理论.成都：电子科技大学出版社，1996
[31] 殷人昆，陶永雷等.数据结构.北京:清华大学出版社，1999
[32] 官章全，唐晓卫.Visual C++ 6.0编程实例详解.北京：电子工业出版社，1999
[33] 钱能. C++程序设计教程.北京：清华大学出版社，2000