Optimal Placemen t of Base Stations in Wireless Indo or T - PDF document

Optimal Placemen t of Base Stations in Wireless Indo or T elecomm unication � Thom F r uh wirth � Ludwig�Maximilians�Univ ersit y Munic h frueh wir�informatik�uni�m uenc hen�de h ttp���www�informatik�uni�m uenc hen�de� � frueh wir� P ascal Brisset Ecole Nationale de l�Aviation Civile P ascal�Brisset�rec herc he�enac�fr Octob er ���� � W ork w as done while at ECR C� Munic h� German y ���

Remarks ABSTRA CT Planning of lo cal wireless comm unication net w orks is ab out installing base stations �small radio transmitters� to pro vide wireless devices with strong enough signals� POPULAR is an adv anced industrial protot yp e that allo ws to compute the minimal n um b er of base stations and their lo cation giv en a blue�prin t of the installation site and information ab out the materials used for w alls and ceilings� It do es so b y sim ulating the propagation of radio�w a v es using ra y tracing and b y subsequen t optimization of the n um b er of base stations needed to co v er the whole building� T aking adv an tage of state�of�the�art tec hniques for programmable application�orien ted constrain t solving� POPULAR is among the �rst practical to ols that can optimally plan wireless comm unication net w orks� �

Thom F r uh � wirth � LMU P ascal Brisset � ENA C Wireless T elecomm unication Reac hable ev erywhere � Flexible � no cabling � Impro v ed qualit y and securit y � ECR C �Siemens� ICL� Bull� Siemens Priv ate Net w orks Siemens Researc h and Dev elopmen t R WTH Aac hen� Comm unication Net w orks Dept� Indo or digital telecomm unication � Need sender stations � Ha v e to plan their lo cation � �

Remarks Pro ject leader� Aac hen� Prof� Dr� W alk e� Hr� Hu�mann ����� �� Mill� Email addresses � �� Mill� F ax mac hines � �� Mill� Mobile phones � ����� W estern Europ e �� Mill� wireless phones� Ger� man y � Mill� Flexible � no cabling required� Impro v ed transmis� sion qualit y and securit y � Propagation of radio w a v es inside buildings� T o da y � the n um b er and p ositioning of base stations is estimated b y an exp erienced sales p erson� W as Op en Problem � W orldwide �rst together with A T�T WISE� � IEEE Exp ert Magazine� USA� Best Application in T elecomm unications ����� � Winner T elecom Application Con test of T elecom Italia at CP��� Conference ����� ���

Thom F r uh � wirth � LMU P ascal Brisset � ENA C The Challenge Optimal placemen t of senders Complete co v erage of site � Minimal n um b er of senders � BS BS BS PABX PSTN �

Remarks Propagation of radio w a v es inside buildings� Curren t systems are cellular in that a base station �sender� transmitter� con trols the links to the trancei� v ers� A �radio� cell is the space that is co v ered b y a sin� gle base station� F or buildings� m ulti�cellular systems are required� b ecause w alls and �o ors absorb part of the radio signal� ���

Thom F r uh � wirth � LMU P ascal Brisset � ENA C Radio W a v e Propagation Radio signal su�ers from� atten uation �w eak ening� due to distance� � shado wing �absorption� through obstacles� � m ultipath propagation due to re�ection� � P ath loss� w alls at � m and � m � log scale 110 107 dB 100 90 80 path loss / dB 70 60 50 40 38 dB 30 1 2 3 4 5 6 7 8 9 10 15 20 25 30 distance / m �

Remarks The mo del is based on the p o w er balance of wireless transmission� It com bines a distance dep enden t term with correction factors for extra path loss due to �o ors and w alls of the building in the propagation path� T o tak e re�ection and m ultipath e�ects in to ac� coun t� a fading r eserve �fade margin� is in tro duced� W e also extended the mo del to tak e the directional ef� fect of an an tenna in to accoun t� since an tennas do not b eam with the same energy in ev ery direction� ���

Thom F r uh � wirth � LMU P ascal Brisset � ENA C The Constrain t Approac h Sim ulation � � Mo delling of site� W alls� Materials � Propagation of radio w a v es �ra y tracing� Optimization � � Constrain t solving �in tersection of radio cells� � Searc h �try equating senders� � Optimization �branc h and b ound� �

No Remarks ���

Thom F r uh � wirth � LMU P ascal Brisset � ENA C Sim ulation of Radio W a v e Propagation Ra y T racing Pfad Wall Wall (xw,yw,zw) Floor2 (xf,yf,zf) Sender Floor1 (xs,ys,zs) �

Remarks Ra y tracing sim ulates the propagation of radio w a� v es through the w alls and ceilings of the building� T o get to the p oin t of minimal sensitivit y �i�e� maxi� mal p ermissible path loss�� eac h path m ust b e follo w ed through the whole building� The v alues of an tenna atten uation in the direction of the path� the path loss due to the distance and the insertion losses due to in tersections of the path with w alls and �o ors are added up to the maximal p ermis� sible path loss� ���

Thom F r uh � wirth � LMU P ascal Brisset � ENA C T est P oin t Grid Co v ers the site test point step/x step step/x H2 H2 H1 H1 1,7m �

Remarks In the sim ulation phase� the c haracteristics of the building are computed using of test p oin ts� Eac h test p oin t represen ts a p ossible receiv er p osition� The test p oin ts are placed on a ��dimensional grid inside the v olume that should b e co v ered� F or eac h test p oin t the space where a base station can b e put to co v er the test p oin t� the �radio cell�� is calculated� The end p oin ts resulting from ra y tracing are used to describ e the h ull of the radio cell� If the test grid is su�cien tly small �sev eral p er squaremeter�� w e can exp ect that if t w o neigh b ouring test p oin ts are co� v ered� the space in b et w een � hence the whole building � can also b e co v ered� ���

Thom F r uh � wirth � LMU P ascal Brisset � ENA C Radio Cells Mo dern Monks� Monastery �

Remarks Note that the radio cell will usually b e a rather o dd�shap ed ob ject� since the receiv ed p o w er ma y exhi� bit discon tin uities b ecause of tin y c hanges in the lo ca� tion � suc h as a mo v e around the corner� ���

Thom F r uh � wirth � LMU P ascal Brisset � ENA C Constrain t Solv er In tersection of radio cells � Sender in rectangle not�empty � S in �A�B���C�D� ��� A�C� B�D� intersection � S in �A��B����C��D��� S in �A��B����C��D�� ��� A � max�A��A��� B � max�B��B��� C � min�C��C��� D � min�D��D��� S in �A�B���C�D�� �