Indoor propagation modelling at microwave frequencies in a ...liu.diva-portal.org/smash/get/diva2:838835/FULLTEXT01.pdfa high capacity microwave telecommunication system called MINI-LINK

Department of Science and Technology Institutionen för teknik och naturvetenskap Linköping University Linköpings universitet

gnipökrroN 47 106 nedewS ,gnipökrroN 47 106-ES

LiU-ITN-TEK-G--15/033--SE

Indoor propagation modellingat microwave frequencies in a

server environmentAndreas Joelsson

Jonathan Ohlsson

2015-06-11

LiU-ITN-TEK-G--15/033--SE

Indoor propagation modellingat microwave frequencies in a

server environmentExamensarbete utfört i Elektroteknik

vid Tekniska högskolan vidLinköpings universitet

Andreas JoelssonJonathan Ohlsson

Handledare Adriana SerbanExaminator Magnus Karlsson

Norrköping 2015-06-11

Upphovsrätt

Detta dokument hålls tillgängligt på Internet – eller dess framtida ersättare –under en längre tid från publiceringsdatum under förutsättning att inga extra-ordinära omständigheter uppstår.

Tillgång till dokumentet innebär tillstånd för var och en att läsa, ladda ner,skriva ut enstaka kopior för enskilt bruk och att använda det oförändrat förickekommersiell forskning och för undervisning. Överföring av upphovsrättenvid en senare tidpunkt kan inte upphäva detta tillstånd. All annan användning avdokumentet kräver upphovsmannens medgivande. För att garantera äktheten,säkerheten och tillgängligheten finns det lösningar av teknisk och administrativart.

Upphovsmannens ideella rätt innefattar rätt att bli nämnd som upphovsman iden omfattning som god sed kräver vid användning av dokumentet på ovanbeskrivna sätt samt skydd mot att dokumentet ändras eller presenteras i sådanform eller i sådant sammanhang som är kränkande för upphovsmannens litteräraeller konstnärliga anseende eller egenart.

För ytterligare information om Linköping University Electronic Press seförlagets hemsida http://www.ep.liu.se/

Copyright

The publishers will keep this document online on the Internet - or its possiblereplacement - for a considerable time from the date of publication barringexceptional circumstances.

The online availability of the document implies a permanent permission foranyone to read, to download, to print out single copies for your own use and touse it unchanged for any non-commercial research and educational purpose.Subsequent transfers of copyright cannot revoke this permission. All other usesof the document are conditional on the consent of the copyright owner. Thepublisher has taken technical and administrative measures to assure authenticity,security and accessibility.

According to intellectual property law the author has the right to bementioned when his/her work is accessed as described above and to be protectedagainst infringement.

For additional information about the Linköping University Electronic Pressand its procedures for publication and for assurance of document integrity,please refer to its WWW home page: http://www.ep.liu.se/

© Andreas Joelsson, Jonathan Ohlsson

Abstract

The Linkoping site is the first of Ericsson’s three information and communication tech-nology centres. This facility will house the company’s complete portfolio and use thelatest cloud technology in order to enable the research and development engineers tomore efficiently test and develop new technologies. In the test lab environment there isa high capacity microwave telecommunication system called MINI-LINK. These systemsoperate at much higher frequencies than more traditional telecommunication systems.In the test lab these systems are communicating with a cable interface instead of itsintended air interface. The purpose of this thesis is to evaluate the potential leakage ofthis system in the test lab environment.

The evaluation of the leakage in the test lab is done by developing an empirical pathloss model for the desired frequencies used by the equipment in the test lab. This modelis later implemented in a leakage simulation tool designed in Matlab, which simulatesand displays the leakage power in a 2D plane. This report mainly focuses on the processof determining the constants and the implementation of the path loss model.

Acknowledgements

We would like to thank Ericsson for providing the opportunity to make this project withthem. We would also like to thank our supervisors and others involved by providingsupport and feedback along the way.

Contents

1 Introduction 1

1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.1 Cellular Networks and MINI-LINK . . . . . . . . . . . . . . . . . 2

1.2 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.3 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.3.1 Pre-study Requirements . . . . . . . . . . . . . . . . . . . . . . . 41.3.2 Model Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 51.3.3 Measurement Requirements . . . . . . . . . . . . . . . . . . . . . 51.3.4 Project Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Theoretical Background 6

2.1 Path Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.1.1 Free-space Path Loss . . . . . . . . . . . . . . . . . . . . . . . . . 62.1.2 Simplified Path Loss Model . . . . . . . . . . . . . . . . . . . . . 72.1.3 Empirical Path Loss Models . . . . . . . . . . . . . . . . . . . . . 7

2.2 Environmental Factors on Radio Propagation . . . . . . . . . . . . . . . 102.2.1 Multipath Propagation . . . . . . . . . . . . . . . . . . . . . . . . 102.2.2 Fading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.3 Indoor Propagation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3 Model Development 13

3.1 Model Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.1.1 Comparison of Models . . . . . . . . . . . . . . . . . . . . . . . . 133.1.2 Initial Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.2 Measurement Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.2.1 Interface Loss Characterization . . . . . . . . . . . . . . . . . . . 153.2.2 SMA Antenna Characterization . . . . . . . . . . . . . . . . . . . 163.2.3 Equipment Parameters . . . . . . . . . . . . . . . . . . . . . . . . 18

3.3 Path Loss Exponent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.3.1 Path Loss Exponent Measurements . . . . . . . . . . . . . . . . . 19

3.4 Rack Attenuation Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.4.1 Rack Attenuation Factor Measurements . . . . . . . . . . . . . . 223.4.2 Solid Object Attenuation . . . . . . . . . . . . . . . . . . . . . . . 24

3.5 Proposed Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

June 25, 2015 CONTENTS

4 Model Verification and Correction 27

4.1 Verification Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . 274.1.1 Measurement Setup . . . . . . . . . . . . . . . . . . . . . . . . . . 274.1.2 Model Deviation . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.2 Model Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294.2.1 Path Loss Exponent Correction . . . . . . . . . . . . . . . . . . . 304.2.2 Rack Attenuation Factor Correction . . . . . . . . . . . . . . . . . 304.2.3 Deviation after Model Correction . . . . . . . . . . . . . . . . . . 31

5 Results 32

5.1 Final Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325.2 Leakage Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

5.2.1 Maximum Allowed Radiated Power . . . . . . . . . . . . . . . . . 335.2.2 Leakage from MINI-LINK Setup . . . . . . . . . . . . . . . . . . . 335.2.3 Model Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6 Discussion and Conclusion 36

6.1 General Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366.2 Requirement Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6.2.1 Pre-study Requirement Evaluation . . . . . . . . . . . . . . . . . 376.2.2 Model Requirement Evaluation . . . . . . . . . . . . . . . . . . . 386.2.3 Measurement Requirement Evaluation . . . . . . . . . . . . . . . 386.2.4 Project Requirement Evaluation . . . . . . . . . . . . . . . . . . . 39

6.3 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406.4 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Appendices 45

A Plotted Measured Data 46

A.1 Open Space Plot for 23.0 GHz . . . . . . . . . . . . . . . . . . . . . . . . 46A.2 Open Space Plot for 18.0 GHz . . . . . . . . . . . . . . . . . . . . . . . . 47A.3 Rack Environment Plot for 23.0 GHz . . . . . . . . . . . . . . . . . . . . 47A.4 Rack Environment Plot for 18.0 GHz . . . . . . . . . . . . . . . . . . . . 48

B Raw data 49

B.1 Path Loss Exponent Measurements . . . . . . . . . . . . . . . . . . . . . 49B.2 Verification Data Measurements . . . . . . . . . . . . . . . . . . . . . . . 50B.3 RAF measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51B.4 Solid Object Attenuation Measurements . . . . . . . . . . . . . . . . . . 52

C Leakage Simulation Tool: User Guide 53

List of Figures

1.1 Illustration of cellular data forwarding . . . . . . . . . . . . . . . . . . . 2

2.1 Free-space path loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.2 Example of multipath components of transmitted signal . . . . . . . . . . 102.3 Illustration of destructive and constructive interference . . . . . . . . . . 11

3.1 Comparison of path loss models . . . . . . . . . . . . . . . . . . . . . . . 143.2 Conversion connector loss characterization . . . . . . . . . . . . . . . . . 163.3 Loss characterization of Sucoflex 104 cable . . . . . . . . . . . . . . . . . 163.4 Characterization with reference antenna . . . . . . . . . . . . . . . . . . 173.5 Characterization with antenna under test . . . . . . . . . . . . . . . . . . 173.6 Measurement setup for determining the path loss exponent . . . . . . . . 193.7 Measured path loss for an open space environment at 23.0 GHz . . . . . 203.8 Measured path loss for an open space environment at 18.0 GHz . . . . . 213.9 Measurement setup for determining the rack attenuation factor . . . . . . 223.10 Line-of-Sight and Non-Line-of-Sight components in the RAF measurements 233.11 Measurement setup solid object attenuation seen from above . . . . . . . 243.12 Estimated path loss for open space at 23.0 GHz . . . . . . . . . . . . . . 263.13 Estimated path loss for open space at 18.0 GHz . . . . . . . . . . . . . . 26

4.1 Verification measurement locations in the test lab environment . . . . . . 284.2 Deviating points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.1 Single source simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . 355.2 Multiple source simulation . . . . . . . . . . . . . . . . . . . . . . . . . . 35

A.1 Measured data for open space at 23.0 GHz . . . . . . . . . . . . . . . . . 46A.2 Measured data for open space at 18.0 GHz . . . . . . . . . . . . . . . . . 47A.3 Measured data for rack environment at 23.0 GHz . . . . . . . . . . . . . 47A.4 Measured data for rack environment at 18.0 GHz . . . . . . . . . . . . . 48

C.1 Default layout of the leakage simulation tool . . . . . . . . . . . . . . . . 53C.2 Simulation environment configuration in progress . . . . . . . . . . . . . 55

List of Tables

1.1 Definition of requirement priority . . . . . . . . . . . . . . . . . . . . . . 41.2 Pre-study requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 Model requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.4 Measurement requirements . . . . . . . . . . . . . . . . . . . . . . . . . 51.5 Project requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.1 Simulation parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.2 Interface losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.3 Component properties at 23.0 GHz . . . . . . . . . . . . . . . . . . . . . 183.4 Component properties at 18.0 GHz . . . . . . . . . . . . . . . . . . . . . 183.5 Path loss exponents in different scenarios at 23.0 GHz . . . . . . . . . . 203.6 Path loss exponents in different scenarios at 18.0 GHz . . . . . . . . . . 213.7 Definition of rack densities . . . . . . . . . . . . . . . . . . . . . . . . . 223.8 Rack attenuation factor for different rack densities at 23.0 GHz . . . . . 233.9 Rack attenuation factor for different rack densities at 18.0 GHz . . . . . 233.10 Solid object attenuation for different separation distances at 23.0 GHz . 243.11 Solid object attenuation for different separation distances at 18.0 GHz . 25

4.1 Deviation of the LOS components . . . . . . . . . . . . . . . . . . . . . 284.2 Deviation of the NLOS components . . . . . . . . . . . . . . . . . . . . 294.3 K for 23.0 GHz model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314.4 K for 18.0 GHz model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314.5 Corrected deviation of the LOS components . . . . . . . . . . . . . . . . 314.6 Corrected deviation of the NLOS components . . . . . . . . . . . . . . . 31

5.1 Measured power of the leakage scenarios . . . . . . . . . . . . . . . . . . 34

6.1 Analysis of Pre-study requirements . . . . . . . . . . . . . . . . . . . . . 376.2 Analysis of Model requirements . . . . . . . . . . . . . . . . . . . . . . . 386.3 Analysis of Measurement requirements . . . . . . . . . . . . . . . . . . . 386.4 Analysis of Project requirements . . . . . . . . . . . . . . . . . . . . . . 39

List of Abbreviations

AF Antenna FactorAUT Antenna Under TestEMC ElectroMagnetic CompatibilityEMI ElectroMagnetic InterferenceFAF Floor Attenuation FactorGSM Global System for Mobile communicationICT Information and Communication TechnologyLOS Line Of SightLTE Long-Term EvolutionNLOS Non Line Of SightPCB Printed Circuit BoardRAF Rack Attenuation FactorRF Radio FrequencyRx ReceptionTx TransmissionWAF Wall Attenuation Factor

Chapter 1

Introduction

In this chapter the background, limitations and requirements of the project will be pre-sented.

1.1 Background

The Ericsson facility in Linkoping is in the process of completing the construction of itstest lab, which is the first of three global test centers. Ericsson’s reason for collecting itsentire portfolio of products in three locations is to allow the engineers to develop and testnew solutions remotely, while Ericsson estimate that they will reduce their total energyconsumption of their test facilities with 40 %, with the aim for a more sustainable future.[8]

Since the equipment in the test lab is operated remotely, the engineer using theequipment in the lab need to know that it is working as intended. The test environ-ment engineer are responsible of safely integrating new equipment and maintaining thehardware in the test lab, in order to prevent potential problems.

Problems facing the test environment engineers when integrating new equipment isgenerally concerning leakages from the equipment in the lab. Since a large portion ofthe products in the Ericsson portfolio is designed to operate in an outdoor environment,the RF leakages need to be characterized and controlled to be able to guarantee a fullyfunctional test environment. These leakages, if the signal strength is large enough, canalso provide a possible undesired access point to the system. The leakage can also posea health risk to the test lab employees if the emitted energy is too high.

Accurately modelling and evaluating potential problems in any leakage scenario is im-portant when sensitive equipment is placed close to each other. This potential problemis more relevant when outdoor equipment is placed in an indoor test environment, usingcables, connectors and waveguides instead of using the intended air interface. Knowl-edge on how to troubleshoot potential problems before they occur is critical knowledgewhen maintaining a large amount of equipment. Knowledge about the possible leakagescenarios and the ability to evaluate different equipment placement is a valuable assetfor engineers responsible for maintaining the system.

This project seeks to develop a tool for engineers to evaluate different leakage sce-

1

June 25, 2015 CHAPTER 1. INTRODUCTION

narios, leakage strength and its propagation characteristics in a server environment. Thetool will give engineers the ability to plan the placement of the equipment and increaseawareness where different leakage scenarios will potentially cause a problem.

1.1.1 Cellular Networks and MINI-LINK

To be able to transmit data from one remote location to another, a connection betweenthe two points are required. Since the devices may not be located in the same area, thetransmitted data will be forwarded via a microwave link and/or Ethernet/fiber in orderto connect the devices.

The increased demand for high data rates and availability of modern communicationsystems requires high performance forwarding for nodes in the communication network.The MINI-LINK system from Ericsson offers the possibility for high capacity transferwhen forwarding data between network nodes. This system allows technologies suchas 4G and LTE to be implemented in a cost efficient way, while preparing the wirelessnetwork for future technologies. [10]

In the following subsections the procedure of connecting the wireless device to theInternet will be explained. The forwarding procedure is illustrated in Figure 1.1.

Figure 1.1: Illustration of cellular data forwarding

Wireless Device to Base Station:

The transmitting device connects to a base station in the telecommunication networkusing 4G or any other applicable technology. The data is sent from the transmittingdevice and received by the base stations antenna. The data is collected and repackagedfrom several devices connected to the same base station.

2


Base Station to Base Station Controller:

The collected data from several connected wireless devices is sent via microwave transmis-sion to the base station controller. The base station controller is responsible of collectingtransmissions from several base stations and repackaging the data.

Base Station Controller to Switching Center:

The data from several base stations are collected and repackaged. This data is forwardedin the same way as between the base station and the base station controller, but may beforwarded to a switching center. The switching center sends the data to its destinationusing either Ethernet or optical fiber. [2]

1.2 Limitations

The main purpose of this project is to evaluate leakage power levels of the MINI-LINKsetup in the test environment at the Ericsson test lab in Linkoping. When investigatingdifferent leakage scenarios, a simulation model can be created to estimate leakage levelsin the environment. There are several ways to construct and implement a model to beable to represent the specific scenario needed. The signal propagation can be modelledeither by a deterministic or an empirical approach.

A deterministic approach uses the description of the physical material in the modellingenvironment. In order to get an accurate model, material parameters such as relativepermittivity, permeability and conductivity has to be specified for the environment. Thisapproach requires a huge amount of data to describe the modelling environment and ahuge computational effort to determine the loss contribution from the environment.

An empirical approach is based on measurements instead of physical properties ofthe materials. This approach can generate models with less computational effort butwith the drawback of being limited to the environment and parameters used in the dataacquisition. [11]

Using this knowledge a model can be formed and appropriate measurements be exe-cuted to be able to verify the model. Since the model will be used to determine signallevels for leakage evaluation, the level of accuracy needed does not warrant a determin-istic model. An empirical modelling approach will be used to determine the signal levelssince it can be verified and used to evaluate the leakage in a shorter time frame.

In the list below the limitations of the project is summarized. Furthermore, therequirements of the project is presented in section 1.3.

• The project duration is 20 weeks

• The model will be based on a empirical modelling method

• The quality and quantity of empirical data will lay the foundation of the model

• The model will only be verified for a maximum of two operating frequencies

• The model will only be verified in the Ericsson test lab in Linkoping

3


• The quality of the model will be determined with standard deviation calculationcompared to verification measurements

• The model will only be simulated in a 2D environment

1.3 Requirements

During the project certain criteria have to be met for the project. The requirements willbe presented and ranked on a priority scale as seen in Table 1.1.

Table 1.1: Definition of requirement priority

Priority Description

1 Critical importance2 High importance3 Low importance

1.3.1 Pre-study Requirements

During the pre-study, knowledge will be acquired in order to fully understand the prob-lem. This knowledge will be used to derive and implement an empirical model. Therequirements for the pre-study can be seen in Table 1.2.

Table 1.2: Pre-study requirements

No. Description Priority

1 Appropriate knowledge about signal leakage 12 Appropriate knowledge of current EMC standards 23 Evaluation of indoor propagation models & methods 14 Measurement techniques at microwave frequencies 15 Appropriate knowledge of Matlab programming 1

4


1.3.2 Model Requirements

In order to create an appropriate tool that implements the simulation model, severalaspects of the model need to be considered. The requirements for the model can be seenin Table 1.3.

Table 1.3: Model requirements


6 Model will be implemented in Matlab 17 Tuning of model parameters in different environments 18 Tuning of model parameters at appropriate frequencies 19 Environment mapping for simulation model 110 Multiple assignable leakage sources in model 111 Random variance consideration of model 312 Simulation will alert if signal level will cause potential security risk 213 Simulation will alert if signal level is above recommended levels 214 Simulation implementation will have a graphical interface 2

1.3.3 Measurement Requirements

A series of measurements need to be performed during the project in order to be able toimplement the empirical simulation model. The requirements for the measurements canbe seen in Table 1.4.

Table 1.4: Measurement requirements


15 Measurements will be performed with appropriate equipment 116 Orientation of measurement and equipment will be considered 117 Height of measurement will be considered 218 Multiple frequencies will be measured 2

1.3.4 Project Requirements

A number of documents, meetings and presentations will be performed during the project.The requirements for the project can be seen in Table 1.5.

Table 1.5: Project requirements


19 Deliver a written report at the end of the project 120 Weekly meetings with supervisor at Ericsson 121 Monthly written report to supervisor at Ericsson 122 Present the project at Ericsson and LiU 1

5

Chapter 2

Theoretical Background

In this chapter, the theoretical background of the project will be presented. The theorywill be used in order to understand and implement the requirements of the project.

2.1 Path Loss

The path loss of a transmitted signal is the energy reduction of the propagating electro-magnetic wave. Understanding and accurately modelling the path loss of a propagatingwave is important to be able to plan and evaluate the range of communications systems.This project uses path loss modelling to determine the leakage power at a certain distancefrom the source.

2.1.1 Free-space Path Loss

The simplest way to model path loss is where only the free-space path loss is takeninto account. The free-space path loss model does not consider the environment it ispropagating in, since the model is based on waves propagating in free-space. The free-space path loss is usually used as a starting point when forming a path loss model whenonly the line-of-sight component is required. The free-space path loss can be seen in (2.1)and (2.2).

PL(d) =λ2

(4πd)2(2.1)

PL(d) dB = 20 log10(d) + 20 log10(f)− 27.55 (2.2)

where λ is the wavelength of the carrier frequency in meters, f is the carrier frequencyin MHz and d is the distance in meter between the transmitter and receiver [1]. A plotof the free-space path loss for a source with an operational frequency of 23.0 GHz can beseen in Figure 2.1.

6

June 25, 2015 CHAPTER 2. THEORETICAL BACKGROUND

Figure 2.1: Free-space path loss

2.1.2 Simplified Path Loss Model

Modelling path loss in complex environments, such as dense urban areas, offices or otherindoor environments, requires a adjustable model for accurate path loss modelling. Thesimplified path loss model uses adjustable factors which can be obtained with both em-pirical and deterministic modelling methods. This gives the simplified path loss model awide range of applicable scenarios. The simplified path loss model is shown in (2.3).

PL(d) dB = −20 log10

(λ

4πd0

)+ 10γ log10

(d

d0

)+ ψdB (2.3)

where λ is the wavelength of the carrier frequency, d0 is the reference distance for themodel in meters, γ is the path loss exponent tuned for a specific environment and ψdB isa Gaussian distributed random variable. This variable is used to describe the variance ofthe model caused by environmental effects. These variations will be explained in section2.2. The reference distance d0 is typically set to 1 m for indoor environments, and γ istypically in the range of 1.6 to 3 for an indoor environment. [2]

2.1.3 Empirical Path Loss Models

Accurately modelling path loss in complex environments requires more than only free-space path loss. There are several path loss models based on empirical data collected forspecific model parameters such as frequency and environment. In this section, a selectionof these models are presented.

7


Hata model

The Hata model is an empirical model typically used for estimating path loss in outdoorurban environments. The Hata model is widely used since its able to model propagationof modern cellular systems with smaller cell sizes and higher frequencies [2]. The Hatamodel is described by (2.4).

PL,urban(d) dB = 69.55 + 26.16 log10(fc)− 13.82 log10(ht)

−a(hr) +

(44.9− 6.55 log10(ht)

)log10(d) (2.4)

where fc is the carrier frequency, ranging from 150 MHz to 1500 MHz, hr and ht arethe height of the receiving and transmitting antenna, ranging from 1-10 m for hr and30-200 m for ht. The distance d ranges from 1 km to 100 km, a(hr) is the correctionfactor, which for small and medium sized cities is given by (2.5) and for larger cities givenby (2.6). [2]

a(hr) dB =

(1.1 log10(fc)− 0.7

)hr −

(1.56 log10(fc)− 0.8

)(2.5)

a(hr) dB = 3.2

(log10(11.75hr)

)2

− 4.97 (2.6)

COST 231 extension to Hata model

Since the Hata model does not cover frequencies over 1.5 GHz, the European cooperativefor scientific and technical research extended the model to cover an higher range offrequencies. The model is described by (2.7).

PL,urban(d) dB = 46.3 + 33.9 log10(fc)− 13.82 log10(ht)

−a(hr) +

(44.9− 6.55 log10(ht)

)log10(d) + CM (2.7)

where fc is the frequency, ranging from 1.5 GHz to 2 GHz, hr and ht are the heightof the receiving and transmitting antenna, ranging from 1-10 m for hr and 30-200 m forht. The distance d ranges from 1 to 10 km and a(hr) is the correction factor as in theHata model, as seen in (2.5) and (2.6). CM is a correction factor for the model with thevalue of 0 dB for medium dense cities and 3 dB for metropolitan areas. [2]

8


COST 231 Multi Wall

The COST 231 Multi Wall path loss model provides a path loss estimation for indoorenvironments and is applicable for frequencies between 900 MHz and 1800 MHz. Includedin the model is a linear attenuation factor for the number of walls in the propagatingpath, as described by (2.8).

PL(d) dB = L0 + 10n log10(d) + Lc +W∑

i=1

(NW,i ·WAFW,i

)(2.8)

where L0 is the path loss in dB at 1 m for the modelled frequency, Lc is an empiricallyderived constants depending on the environment in dB and n is the power decay index.NW,i is the number of walls in the transmitting path and WAFW,i is the wall attenuationfactor. The WAF is typically set to 3.4 dB for light walls and 6.9 dB for heavy walls.[4][13]

ITU-R path loss model

The radio section of the International Telecommunication Union, ITU-R, implements acombination of average path loss and site specific data for estimating path loss. Includedin the model is floor attenuation to the transmitted signal. The basic ITU-R model isdescribed by (2.9).

PL(d) dB = 20 log10(f) +N log10(d) + Lf (n)− 28 (2.9)

where f is the frequency in MHz, N is the power loss coefficient ranging from 22 to33 in an office environment in the frequency range of 700 MHz to 70 GHz. The floor lossfactor, Lf , ranges from 9 dB at 900 MHz to 22 dB at 5.8 GHz for single floor loss. [12]

WINNER II model

In the WINNER II channel models, models for both indoor and outdoor environmentsare derived. The model for indoor environments is described by (2.10) for the line-of-sightcomponent and (2.11) for the non-line-of-sight. [14]

PL,LOS(d) dB = 46.8 + 18.7 log10(d) + 20 log10

(f

5

)(2.10)

PL,NLOS(d) dB = 46.4 + 18.7 log10(d) + 20 log10

(f

5

)+WAF ·NW (2.11)

where f is given in GHz between 2 and 6 GHz and d is the distance ranging from 3to 100 m. WAF is the wall attenuation factor in dB and NW is the number of walls inthe propagating path.

9


2.2 Environmental Factors on Radio Propagation

An propagating electromagnetic wave may be subjected to several propagation effects,such as reflection, diffraction, scattering and object attenuation. These aspects need tobe considered when developing propagation models. This section will look into thesefactors.

2.2.1 Multipath Propagation

In urban and indoor environments, the signal has several additional paths of propagationbesides the line-of-sight component. Reflection of objects, diffraction and scatteringwill affect the signal strength at the receiver. This phenomena is known as multipathpropagation. In Figure 2.2, the diffraction and reflection multipath components areillustrated.

Figure 2.2: Example of multipath components of transmitted signal

The multipath propagation problems can be solved using Maxwell’s equations, butthe computational effort is generally to great for a practical implementation. Instead,the electromagnetic waves are represented as simple particles, thus reducing the com-putational complexity needed. Diffraction, reflection and scattering problems are solvedwith geometrical equations instead of solving the partial differential equations used inMaxwell’s equations. [2]

2.2.2 Fading

Transmitted signals usually suffer from random variations in the signal level at the re-ceiver. Shadow fading, or slow fading, is caused by reflection and scattering of objects inthe signal path. Generally, when considering shadow fading in outdoor and urban envi-ronments, the objects causing the fading are large and the shadowing effect is consideredconstant over a given number of wavelengths. [7]

The most common model used is the log-normal shadowing model. It has beenempirically confirmed to accurately model variation in received power for indoor andoutdoor environments. When calculating the variance of the shadow fading, the difference

10


between the model and measured values at several distances is needed. The variance canthen be calculated using (2.12). For outdoor environments, σψdB

is typically in the rangeof 4 dB to 13 dB. [2]

σ2

ψdB=

1

N

N∑

i=1

[Mmeasured(di)−Mmodel(di)

]2(2.12)

Fast fading variations behave in the same way as slow fading, but are generally causedby minor variation closer to the receiving antenna due to multipath components from thetransmitter. The multipath components cause destructive or constructive interference,as seen in Figure 2.3, affecting the received signal power, due to the relative phase of theelectromagnetic waves. For indoor environments, the fading can be considered to havefast fading characteristics. [7]

Figure 2.3: Illustration of destructive and constructive interference

2.3 Indoor Propagation

When modelling path loss, free-space path loss is not sufficient to accurately model theactual path loss in an indoor environment. The propagation environment is generallymore complex with object causing attenuation, reflections and diffractions of the trans-mitted electromagnetic waves.

For indoor propagation there are three major ways to model the propagating wave;ray tracing, dominant path and direct path. Ray tracing is the most complex of themethods, as it often uses a deterministic modelling approach. The ray tracing methodapproximates the electromagnetic waves as rays to be able to determine the contribution

11


of each multipath component. Modelling path loss using ray tracing methods requiresmore data and is more computationally demanding, but yields a more accurate result.

Direct path models are the most computational efficient, since the model only con-siders the direct path between the transmitter and receiver. Models using the directpath method does not only consider free-space loss, but may also consider loss causedby objects in the propagation path. Typically propagation through walls and floors isconsidered in these models, as described by (2.13).

PL,total = PL(d) +

Nf∑

i=1

FAFi +Nw∑

i=1

WAFi (2.13)

where FAF is the floor attenuation factor, WAF is the wall attenuation factor andPL(d) is the path loss from any given path loss model.

When analyzing different typical scenarios for propagation, it has been found that inmany cases there are one path of propagation that has the largest contribution to thereceived signal strength. The dominant path models calculates the path loss contributionfor a series of propagation paths. The model then disregards all paths but the dominantone. The dominant path models are less computational demanding than the ray tracingmodels and are more accurate than the direct path models.

12

Chapter 3

Model Development

In this chapter, models described in section 2.1 will be compared. Then, an initial modeladapted to the project specifications will be presented.

3.1 Model Selection

In the requirements previously presented in section 1.3.2, the model needs to work atspecified frequencies. Since the main operational frequency of the MINI-LINK systemused in the test lab is 23 GHz, the model need to be able to handle this frequency. Asecondary frequency of 18 GHz was selected in order to extend the usage of the model.18 GHz was selected since it is an operational frequency being used by some of theMINI-LINK radio units in the test lab.

3.1.1 Comparison of Models

In order to be able to select a model to implement, a preliminary simulation of the modelsin section 2.1 was performed. The parameters used for the simulations can be seen inTable 3.1. The simulations have all been performed with a carrier frequency of 23 GHz.

Table 3.1: Simulation parameters

Model Parameter Value

Simplified Path loss model d0 1 mγ 2.5

ITU-R N 25

Hata & COST 231 ext. to Hata ht 1 mhr 1 mCm 0

COST 231 Multi Wall L0 20 log10

(λ4π

)

LC 0

13

June 25, 2015 CHAPTER 3. MODEL DEVELOPMENT

A path loss comparison of the selected models can be seen in Figure 3.1. The com-parison only consider the line-of-sight component in the models.

Figure 3.1: Comparison of path loss models

The free-space model is accurate when the line-of-sight component is dominant andreflection is negligible. This model is not suitable in an indoor environment, since it doesnot take reflections, diffusion and object attenuation into account, which is not negligiblein this kind of indoor environment.

The Hata and COST 231 extension to Hata models may be very useful for cellularcoverage estimation for larger areas with the frequencies covered, but is not suited formodelling systems at the frequencies nor the environment needed for this project. Thiscan be seen in Figure 3.1, as the path loss is significantly higher than for the comparedmodels.

The COST 231 Multi Wall, ITU-R model and WINNER II gives an idea how indoorpath loss models are designed. These models generally give environment properties forgeneral cases but not for the environment required for this project.

The simplified path loss model is adjustable for any frequency and environment, andsuch is suitable for an indoor propagation model at a generic frequency as required bythis project. Object attenuation needs to be taken into consideration when implementingthe final model, which the basic simplified path loss model does not.

14


3.1.2 Initial Model

Using the conclusions of section 3.1.1, an initial model can be selected. The model is basedon the simplified path loss model, with aRAF (Rack Attenuation Factor) for attenuationdue to objects in the propagation path. For indoor environments the reference distanceis set to d0 = 1 m. The path loss and object attenuation will be empirically determinedfor the model. The initial model is described by (3.1).

PL = −20 log10

(λ

4πd0

)+ 10γ log10

(d

d0

)+RAF+ ψdB (3.1)

3.2 Measurement Equipment

To determine the path loss component and the RAF, the measured values need to beadjusted for gain and losses in the measurement equipment. The gains and losses willbe characterized in section 3.2.1 and 3.2.2. The following measurement equipment wasused:

• Signal Analyzer, Keysight PXA N9030A

• Signal Generator, Keysight MXG N5183B

• Horn Antenna 18.0 - 26.5 GHz, A.H. Systems SAS-587

• PCB SMA connector (transmitter antenna), Rosenberger

• Low loss cable, A.H. Systems SAC-26G

• RF cable, HUBER+SUHNER Sucoflex 104

• Precision 2.4 mm to SMA converters

The signal analyzer has a displayed noise floor of -100 dBm with a configured analysisand video bandwidth of 1 kHz. Using a bandwidth of 1 kHz allows the transmitted signalto be separated from adjacent signals, while accurately representing the received power.These settings will be used for all the measurements.

3.2.1 Interface Loss Characterization

To be able to determine the gain offset of the measurements, the equipment losses needto be characterized. This factor specified as LMeasure in (3.5).

For the measurements, the SAC-26G cable was used as a reference since it has char-acterization data provided by A.H. Systems Inc. An illustration of the measurementsetup can be seen in Figure 3.2 for the conversion connector loss characterization, andin Figure 3.3 for the characterization of the Sucoflex cable. The loss for each setup wasdetermined by subtracting the transmitted power with the received power and the knowlosses. The measurement results are summarized in Table 3.2.

15


Figure 3.2: Conversion connector loss characterization

Figure 3.3: Loss characterization of Sucoflex 104 cable

Table 3.2: Interface losses

Component 23.0 GHz 18.0 GHz

SAC-26G 1.90 dB 1.61 dBPrecision 2.4 mm to SMA converter 1.13 dB 0.86 dBSucoflex 104 0.81 dB 0.66 dB

3.2.2 SMA Antenna Characterization

To compare the results as predicted by the proposed model to the measured results, theantenna gains need to be characterized. The receiver antenna is a standard gain hornantenna, which has been characterized and calibrated by A.H. Systems Inc [6]. As atransmitter antenna, a PCB SMA connector was used. However, its gain is unknownand need to be characterized. The gain of the transmitter antenna can be characterizedwith a method called the gain comparison method. This method requires three antennasin order to calculate the gain of the Antenna Under Test (AUT).

The gain comparison method can be utilized by using a spectrum analyzer and asignal generator. First the reference antenna is connected to the spectrum analyzerand the ”Don’t Care”-antenna, marked as X in Figure 3.4, is connected to the signalgenerator. The ”Don’t Care”-antenna is an antenna which gain is not required for thecharacterization, but has to have a sufficient dynamic range in order to transmit to the

16


AUT. The reference antenna is removed and the AUT is connected to the spectrumanalyzer as shown in Figure 3.5. [16]

Figure 3.4: Characterization with reference antenna

Figure 3.5: Characterization with antenna under test

The received power for the described measurements is given by (3.2).

Pr,dBm = Pt,dBm − PL +Gt,dBi +Gr,dBi − LMeasure (3.2)

where Pr,dBm and Pt,dBm are the received and transmitted power, PL is the path lossbetween the transmitter and receiver, Gt,dBi and Gr,dBi are the transmitter and receivergains and LMeasure is the interface losses.

Since the measurements will be carried out in the same environment and with thesame interface losses, the equation from the two measurement setups can be subtractedto obtain the gain of the AUT, as shown in (3.3).

GAUT = Pr,REF − Pr,AUT +GREF (3.3)

where Pr,REF and Pr,AUT is the received power for the respective measurement. GREF

is the gain of the reference antenna, and GAUT is the gain of the AUT. The results ofthe antenna characterization are summarized in section 3.2.3.

17


3.2.3 Equipment Parameters

Using the methods described in section 3.2.1 and 3.2.2, the component parameters weredetermined. The interface and antenna parameters for an operational frequency of 23.0GHz are presented in Table 3.3 and in Table 3.4 for 18.0 GHz.

Table 3.3: Component properties at 23.0 GHz

Component Gain

Horn antenna 15.3 dBiSignal Analyzer cables and connectors -3.03 dBSMA Antenna 1.2 dBiSignal Generator cables and connectors -1.97 dB

Table 3.4: Component properties at 18.0 GHz

Component Gain

Horn antenna 14.0 dBiSignal Analyzer cables and connectors -2.47 dBSMA Antenna 2.3 dBiSignal Generator cables and connectors -1.52 dB

3.3 Path Loss Exponent

The path loss exponent of the initial model in (3.1) determines the rate the power de-creases over distance. Measurements need to be performed in different scenarios to beable to determine the environmental factor of the path loss. The path loss exponent willbe determined for the following scenarios:

• Open space

• Populated rack environment

During the measurements, the transmitter antenna had a fixed position in the en-vironment, while the receiving antenna will be placed at different distances from thetransmitting antenna. The measurements were performed in small in small enough spa-cial intervals for an accurate estimation of path loss characteristics. An illustration ofthe measurement method is shown in Figure 3.6.

18


Figure 3.6: Measurement setup for determining the path loss exponent

When performing measurements for the path loss exponent, additional factors needto be considered in the measurements. The following parameters need to be considered:

• Loss in cable interface

• Gain of receiver antenna

• Gain of transmitter antenna

• Orientation/polarization of the antennas

The collected data will be adjusted for relative gain of the measurement equipmentand then plotted in Matlab.

3.3.1 Path Loss Exponent Measurements

The path loss exponent is assumed to be a scaling factor for a logarithmic function, asseen in (3.1). The measurements were performed with a distance interval of 0.5 m anda range of 1-10 m for the open space measurements and 1-6 m in the rack environment.Five series of measurements were performed for each frequency in order to give a goodapproximation of the path loss exponent.

The fit used to approximate the path loss exponent is based on least-square method,which fits a linear curve to the data as it minimizes the summed square of the residuals.The least-square linear fit is implemented in Matlab with the Curve Fitting Toolboxsoftware. The equation for determining the sum of the squared residuals can be seen in(3.4). [18]

S =n∑

i=1

(yi − yi

)2

(3.4)

where S is the square sum of the residuals, yi is i:th data point and yi is the fitteddata point for the i:th value.

In Figures 3.7 and 3.8, the path loss calculated by (3.5) is represented by a black dot.The calculated average path loss is represented by a red star, and the fitted line curveis represented by a blue line. The fitted curve is represented as a linear function in thepresentation of the measured values because of the logarithmic scaled axes.

PL = Pt,dBm − Pr,dBm −Gr,dBi −Gt,dBi + LMeasure (3.5)

19


Using the method described in [17] gives the ability to extract the path loss exponentfor the different scenarios. The measured data for the rack environment is calculated inthe same way as the open space measurements. The plotted received power can be seenin Appendix A and the raw data can be found in Appendix B.

Path loss exponent at 23.0 GHz

The plotted data for the open space measurement for 23.0 GHz can be viewed in Figure3.7 and are summarized in Table 3.5.

Figure 3.7: Measured path loss for an open space environment at 23.0 GHz

Table 3.5: Path loss exponents in different scenarios at 23.0 GHz

Scenario γOpen space 1.86Rack environment 1.82

20


Path loss exponent at 18.0 GHz

The plotted data for the open space measurement for 18.0 GHz can be viewed in Figure3.8 and are summarized in Table 3.6.

Figure 3.8: Measured path loss for an open space environment at 18.0 GHz

Table 3.6: Path loss exponents in different scenarios at 18.0 GHz

Scenario γOpen space 1.97Rack environment 1.83

3.4 Rack Attenuation Factor

The RAF introduced in section 3.1.2, is initially assumed to be linearly proportional tothe distance propagated through the rack. The RAF is also assumed to depend on thedensity of the server racks, where a more dense rack will attenuate the signal more thana lower dense rack. The initial RAF equation is given by (3.6).

RAF =

NR∑

i=i

ρi · di (3.6)

where ρi is the attenuation constant depending on the rack density, and di is thedistance in meters the signal travels through a rack and NR is the number of racks in thepropagation path.

21


To determine the RAF, a series of measurement have to be performed for differentscenarios. The measurement scenarios to determine the attenuation constant ρ is illus-trated in Figure 3.9. The receiver antenna will be displaced vertically along the serverrack. This combined with the path loss of the environment will determine the finalestimate values for the RAF.

The measurement scenarios to determine the attenuation constant ρ is illustrated inFigure 3.9.

Figure 3.9: Measurement setup for determining the rack attenuation factor

This measurement will be performed in the different density cases, since the serverracks in the test lab are not equally populated. The population density will be a factorsince the separation between the rack equipment will determine if the signal will have aline-of-sight component or not when propagating through the rack. Four different serverrack densities have been defined to more accurately model de object attenuation, asshown in Table 3.7.

Table 3.7: Definition of rack densities

Scenario Population percentage

Lightly populated rack 10 - 40 %Medium populated rack 40 - 70 %Heavily populated rack 70 - 90 %Solid object 90 - 100 %

3.4.1 Rack Attenuation Factor Measurements

To obtain an estimate value for the losses, measurements were carried out as illustrated inFigure 3.10. Three series of measurements with different receiver heights were performedfor each rack density. The object attenuation was derived by subtracting the the equiva-lent open space path loss for each measurement. The use of different receiver heights is to

22


enable both line-of-sight and non-line-of-sight components to affect the average receivedpower. This will give a more accurate average attenuation for the different rack densities.

Figure 3.10: Line-of-Sight and Non-Line-of-Sight components in the RAF measurements

Rack attenuation factor at 23.0 GHz

The calculated average values for the ρ in dB/m at 23.0 GHz can be seen in Table 3.8.

Table 3.8: Rack attenuation factor for different rack densities at 23.0 GHz

Scenario ρLight rack density 4.5Medium rack density 6.0High rack density 19.0

Rack attenuation factor at 18.0 GHz

The calculated average values for the ρ in dB/m at 18.0 GHz are shown in Table 3.9.

Table 3.9: Rack attenuation factor for different rack densities at 18.0 GHz

Scenario ρLight rack density 8.4Medium rack density 11.2High rack density 17.6

23


3.4.2 Solid Object Attenuation

In the case of propagation through a solid object, there will not be any line-of-sightcomponent available, as illustrated in Figure 3.10. Therefore, the measurement setupwas changed compared to the setup used in section 3.4.1. Instead of moving the receivingantenna vertically it is moved horizontally along the object. This method is used sincethe are no line-of-sight components available for the receiving antenna, as shown inFigure 3.10. In addition, the measurement were performed with three different separationdistances, as seen in Figure 3.11. Different separation distances will indicate how themultipath components affect the received power. These measurements will be used inorder to estimate a loss factor for solid objects.

For each separation distance a series of measurements were performed. The averageattenuation value was calculated for each series of measurements. The results of themeasurements are shown in Table 3.10 and 3.11.

Figure 3.11: Measurement setup solid object attenuation seen from above

Rack attenuation factor for solid object at 23.0 GHz

The calculated average values for the ρ in dB/m for 23.0 GHz can be seen in Table 3.10.

Table 3.10: Solid object attenuation for different separation distances at 23.0 GHz

Separation ρ2.9 m 32.04.9 m 30.26.9 m 22.4

24


Rack attenuation factor for solid object at 18.0 GHz

The calculated average values for the ρ in dB/m for 18.0 GHz are shown in Table 3.11.

Table 3.11: Solid object attenuation for different separation distances at 18.0 GHz

Separation ρ2.9 m 27.74.9 m 26.16.9 m 19.7

The decreed object attenuation with increased separation distance can be explainedby the multipath properties of indoor propagation. The increased number of availablemultipath components at the receiver will reduce the apparent attenuation of the solidobject.

3.5 Proposed Model

After performing the necessary measurements, the initial model in (3.1) was modifiedin order to include the measured values in section 3.3 and 3.4. Moreover the model isrewritten to be frequency dependent instead of wavelength dependent as seen in (3.7).

PL = 20 log10(f) + 10γ log10(d)− 20 log10

(c

4π

)+RAF+ ψdB (3.7)

where c is the speed of light in m/s and f is the operational frequency in Hz.The path loss model can be reduced further as shown in (3.8). With the obtained

results for the path loss exponent, the model can be compared with the fitted curve fromthe measurements in section 3.3.1. The comparison can be seen in Figure 3.12 for 23.0GHz and Figure 3.13 for 18.0 GHz.

PL = 20 log10(f) + 10γ log10(d)− 147.5 +RAF+ ψdB (3.8)

25


Figure 3.12: Estimated path loss for open space at 23.0 GHz

Figure 3.13: Estimated path loss for open space at 18.0 GHz

This model will initially be used in the simulation model and and it will be furtherprocessed and evaluated in chapter 4.

26

Chapter 4

Model Verification and Correction

In this chapter the preliminary model will be evaluated and optimized in order to createa more accurate model. Verification measurements were performed in order to evaluateand correct the path loss model.

4.1 Verification Measurements

In order to evaluate the accuracy of the model, verification measurements were performedin the test lab environment. This section will describe how the measurements werecollected and show the deviation of the preliminary model described in (3.8).

4.1.1 Measurement Setup

The leakage simulation tool will implement the path loss model using a direct pathmodelling method. The verification measurements were performed using the direct pathcomponent of the transmitted signal. This method was used in order to more accuratelyrepresent the direct path modelling method. The verification measurements were per-formed for both LOS and NLOS locations in the test lab. This allows the final pathloss model to be adjusted more accurately. The measurement locations are placed in a 2meter by 2 meter grid in the test environment, illustrated in Figure 4.1.

27

June 25, 2015 CHAPTER 4. MODEL VERIFICATION AND CORRECTION

Figure 4.1: Verification measurement locations in the test lab environment

4.1.2 Model Deviation

In order to evaluate the accuracy of the model the deviation of the model needs to becalculated. The deviation of the model is assumed to be normally distributed with amean of µ = 0 [2].

The normal distribution is symmetrical and has the property of containing a percent-age of its values within a set number of standard deviations from its mean. Within 2σabove and below the mean, 95% of the possible outcomes will be included in the distri-bution [5]. This characteristic will be used to evaluate the possible worst case scenariofor the signal leakage levels.

Calculating the standard deviation for the LOS and NLOS components separatelywill indicate where the model needs to be corrected. The calculated deviation for themodel can be seen in Table 4.1 for the LOS components and Table 4.2 for the NLOScomponents.

Table 4.1: Deviation of the LOS components

Frequency σ µ MAX

23.0 GHz 3.91 dB 1.27 dB 11.29 dB18.0 GHz 4.81 dB 0.36 dB 12.25 dB

28


Table 4.2: Deviation of the NLOS components

Frequency σ µ MAX

23.0 GHz 16.11 dB -4.13 dB 43.10 dB18.0 GHz 14.22 dB -8.70 dB 56.10 dB

4.2 Model Correction

Comparing the deviation between the LOS and NLOS components, it can be seen thatthe model is less accurate in the NLOS case. This is due to larger residual values in thecalculation of the standard deviation. The modelled path loss combined with the objectattenuations are higher than the measured path loss in the NLOS cases. The residualsexceeding 15 dB is represented with a blue circle in Figure 4.2.

Figure 4.2: Deviating points

The large deviation of the NLOS case can be partially explained by the result whichwere obtained in section 3.4.2. It indicated that with increased transmitter-receiverseparation the apparent attenuation of the object is reduced. Alternatively this can beexplanation by the dominant path aspect of the propagating signal.

29


4.2.1 Path Loss Exponent Correction

The simulation of the preliminary path loss model, seen in (3.8), does not fully representthe data fit as seen in Figure 3.12 and 3.13. This offset can be explained by the meanvalue of the deviation calculations seen in Table 4.1, as the µ 6= 0. This offset is 3.4dB for the 23.0 GHz model and 1.0 dB for the 18.0 GHz model. This offset is assumedto be frequency dependent, however with only two modelled frequencies this can not befurther investigated.

The offset between the preliminary model and the data fit could be decreased byadjusting the value of the path loss exponent. This adjustment will reduce the mean errorfor shorter distance, however this adjustment will reduce the validity of the model withincreased simulation distances. Since the standard deviation for the model is below 5.0dB with the current implementation, the validity of the LOS components are consideredto be acceptable. With these factors considered, the path loss exponent will not beadjusted in the final implementation of the path loss model.

4.2.2 Rack Attenuation Factor Correction

In the simulations of the preliminary implementation of the path loss model it can beseen that the deviation of the NLOS components are considerably larger than the LOScomponents. This can be seen in the standard deviation and the maximum deviation inTable 4.2.

The initial assumption of the linear property of the RAF may cause this increaseddeviation. The most troublesome locations are where there are multiple objects obstruct-ing the path between the transmitter and receiver. Observations on multiple floor lossesshows that the apparent attenuation of consecutive floors are not linear compared to asingle floor loss. In an office environment the attenuation of the second floor is roughly30% of the first floor [12]. Adjusting for this observation in the calculation of the RAF

may reduce the deviation of the NLOS components. The new implementation of theRAF calculations can be seen in (4.1).

RAF = ρ1 d1 +K ·

NR∑

i=2

ρi di (4.1)

The optimal value for K is derived by calculating the standard deviation and themean deviation of the NLOS components with different K values. The results of thesecalculations can be seen in Table 4.3 for 23.0 GHz and Table 4.4 for 18.0 GHz. Theinitial implementation of the RAF calculations corresponds to K = 1 used in (4.1).

30


Table 4.3: K for 23.0 GHz model

K σ µ MAX

0.1 9.05 dB 4.10 dB 18.47 dB0.2 8.37 dB 3.18 dB 18.47 dB0.3 8.04 dB 2.27 dB 18.47 dB0.4 8.09 dB 1.36 dB 18.47 dB0.5 8.51 dB 0.44 dB 18.47 dB0.6 9.27 dB -0.47 dB 23.86 dB0.7 10.27 dB -1.39 dB 27.17 dB0.8 11.47 dB -2.30 dB 32.48 dB0.9 12.80 dB -3.21 dB 37.79 dB1.0 14.22 dB -4.13 dB 43.10 dB

Table 4.4: K for 18.0 GHz model

K σ µ MAX

0.1 8.38 dB 0.70 dB 18.60 dB0.2 7.99 dB -0.35 dB 18.60 dB0.3 8.02 dB -1.39 dB 18.60 dB0.4 8.46 dB -2.44 dB 23.95 dB0.5 9.26 dB -3.50 dB 27.64 dB0.6 10.33 dB -4.52 dB 33.33 dB0.7 11.60 dB -5.57 dB 39.02 dB0.8 13.01 dB -6.61 dB 44.71 dB0.9 14.53 dB -7.65 dB 50.40 dB1.0 16.11 dB -8.69 dB 56.10 dB

4.2.3 Deviation after Model Correction

Changing the definition of the RAF improves the overall accuracy of the model. Theresults of introducing K can be seen on the µ and σ values in Table 4.3 and 4.4.

The final path model will be implemented using the originally derived path loss expo-nents and attenuation constants for the RAF calculations. The implementation of theRAF has been reworked from (3.6) to (4.1). Selecting a K value of 0.3 for the RAF

calculations gives the best compromise between the standard and mean deviations forboth frequencies, as shown in Table 4.3 and 4.4. The deviations for the final path lossmodel can be seen in Table 4.5 and 4.6.

Table 4.5: Corrected deviation of the LOS components

Frequency σ µ MAX

23.0 GHz 3.91 dB 1.27 dB 11.29 dB18.0 GHz 4.81 dB 0.36 dB 12.25 dB

Table 4.6: Corrected deviation of the NLOS components

Frequency σ µ MAX

23.0 GHz 8.04 dB 2.27 dB 18.47 dB18.0 GHz 8.02 dB -1.39 dB 18.60 dB

31

Chapter 5

Results

This chapter will present the results of the final model and its implementation. Theaspects of different leakage scenarios will be investigated and simulated using the finalpath loss model.

5.1 Final Model

In the leakage simulation tool, the path loss model will be implemented in order tocalculate the potential received power at any point in a 2D space. Using the leakagepower and the path loss model will give the received power at any point in the 2D space.The simulation model can be seen in (5.1).

Pr(d) = Pleakage − 20 log10(f)− 10γ log10(d) + 147.5−

(ρ1 d1 + 0.3

NR∑

i=2

ρi di

)(5.1)

where Pr is the received power and Pleakage is the leakage power. The remainingcomponents are from the preliminary path loss model in (3.8).

In the worst case scenario the standard deviation of the NLOS case will be used toevaluate the signal strength. The standard deviation of the NLOS case is roughly 8.0dB for both the 23.0 GHz and the 18.0 GHz model. Currently there are no known com-mercially used indoor path loss model at the microwave frequencies used in this report.Hence the implemented path loss model are compared with results from models designedfor significantly lower frequencies. The resulting standard deviation for the NLOS com-ponents is roughly 8.0 dB for both 18.0 and 23.0 GHz, this result is be compared withstandard deviations that ranges between 7 and 17 dB retrieved in [12][24][25]. Since theobtained standard deviation is in the lower range in that comparison, the final prop-agation model is assumed to be valid and can be applied to evaluate possible leakagescenarios.

32

June 25, 2015 CHAPTER 5. RESULTS

5.2 Leakage Simulations

The simulation model in (5.1) will be used to evaluate different leakage scenarios in theMINI-LINK setup used in the test lab. The worst case leakage power will be used toevaluate the possible scenarios.

5.2.1 Maximum Allowed Radiated Power

Evaluating the worst case leakage scenarios, the maximum allowed radiated power isrequired. The maximum exposure limit set by the responsible authority (Stralsaker-hetsmyndigheten) in the frequency range between 2 GHz and 300 GHz is 10 W/m2, ora field strength of 155.7 dBµV/m [19]. According to the MIL-STD-461F the radiatedsusceptibility of ground equipment in the frequency range 18-40 GHz is set to be able tohandle 50 V/m, or a 154 dBµV/m [15]. This level is below the maximum level set byStralsakerhetsmyndigheten and will be used to calculate the maximum allowed power.Using the characterization data of the SAS-587 reference antenna and a 50 Ω systemimpedance, the maximum power can be calculated as seen i (5.2) [20].

PMAX = VLim − 107− AF + LMeasure −Gr (5.2)

where PMAX is the maximum allowed power in dBm, VLim is the maximum allowedfield strength in dBµV/m, AF is the antenna factor of the antenna in dB/m, LMeasure isthe interface loss in dB and Gr is the gain of the antenna in dBi.

The maximum allowed radiated power is -8.5 dBm for 23.0 GHz and -6.7 dBm for18.0 GHz.

5.2.2 Leakage from MINI-LINK Setup

In order to understand the potential leakage scenarios, the equipment connecting theMINI-LINK radio units will be evaluated. The following equipment is used for transmit-ting the signals between the MINI-LINK radio units in the test lab:

• Waveguide

• Waveguide to coaxial converter

• Coaxial cable

• Attenuators

The connection between the majority of the MINI-LINK radio units uses a Sucoflex104 cable as listed in section 3.2. The shield used in this cable is a silver-plated coppertape with an additional silver-plated copper braid. This shield setup has a leakageattenuation of about 95 dB [21]. Some of the MINI-LINK radio units are connected witha waveguide instead of the Sucoflex cable. Typically, with gaskets and proper assembly,the waveguide has a leakage attenuation of about 90 dB [22]. This leaves the connectorof the cable as the major leakage contributor [23].

33


Evaluating the leakage from the SMA connector, a 50 Ω termination was connectedto the end of the Sucoflex cable. The power was measured with a transmitted power of30 dBm at a distance of 2λ from the connector. This power was used since the maximumtransmitted power of the MINI-LINK units is in the 30 dBm range. The measured powerof this test can be seen in Table 5.1. The reference torque is 90 Ncm with a Rosenberger32W100-016 torque wrench.

Table 5.1: Measured power of the leakage scenarios

Scenario 23.0 GHz 18.0 GHz

Torque wrench -53.4 dBm -50.3 dBmFinger tight -49.3 dBm -54.9 dBm1/4 revolution loosened -41.6 dBm -41.1 dBm1/2 revolution loosened -29.5 dBm -34.1 dBm

With the measured power adjusted for the gain and losses in the measurement equip-ment, the leakage power is found to be roughly 70 dB below the transmitted power forthe scenario with the connector 1/2 revolution loosened. This leakage level is 20 dB higherthan the leakage from the shield and waveguide. This leakage scenario will be used forthe leakage simulations in the test environment.

5.2.3 Model Simulations

Simulating the leakage in the test environment requires the simulation tool to accuratelyrepresent the actual power levels. The implemented leakage simulation tool is regulatedby the requirements in Table 1.3.

In Figure 5.1 the environment layout used in section 4.1.1 is recreated in the simulationtool. A single leakage source of 0 dBm at 23.0 GHz is configured to replicate this scenario.This configuration was used in order to replicate the verification measurements.

34


Figure 5.1: Single source simulation

In Figure 5.2 the environment is the same as in Figure 5.1. Three leakage sources isconfigured with a frequency of 18.0 GHz and leakage power of -40 dBm. This leakagepower of -40 dBm corresponds to a radio unit transmitting with a power of 30 dBm withthe SMA connector loosened half a revolution, as seen in section 5.2.2.

Figure 5.2: Multiple source simulation

A user guide of the simulation tool and its features can be found in Appendix C.

35

Chapter 6

Discussion and Conclusion

The primary purpose of the project was to investigate and evaluate potential leakagescenarios in the test lab. Two primary aspects of the leakage needed to be evaluated;the security and the health aspects. These parts are of critical importance to the testenvironment engineers to ensure the operational capability of the test lab.

6.1 General Discussion

During the process of developing the path loss model there have been no available studiesor literature that cover the specific frequencies and environment used in this thesis.Hence, while deriving the path loss model comparisons were made with models designedfor other frequencies and environments.

From section 3.3 it can be seen that the derived path loss exponent results in a reducedloss over a certain distance compared to free space loss. This indicates that there arelower losses at higher frequencies, compared to typical telecommunication frequencies,which is something that are not always observed or easily explained. Typically signals athigher frequencies are more affected by object attenuations, but less obstruction in thetransmission path may lead to lower losses [12]. Comparing the derived path loss expo-nent with results from other path loss models designed for high microwave frequenciesgives an indication of the same characteristics [12]. With this aspect the derived pathloss exponents from section 3.3 is considered to be applicable in the desired environment.

Modelling the attenuation of objects in the transmission path proved to result in amuch higher deviation compared to the measurements conducted in the test lab. Initiallythe attenuations were assumed to be linear to the distance travelled through the object.This created large model deviations compared to the performed verification measure-ments. Adjustments of the particular attenuations and the path loss exponent provedto have a much higher impact on the characteristics of the model with only small im-provements to the overall accuracy. Scaling the object attenuation after the first objectimproved the standard deviation of the model. The ρ value for the specific rack densitiesis not changed in the current implementation of the RAF modelling method.

Some problems still remains, such as the mean of the deviation are not fully centredaround zero. Since the amount of data used for these calculations are limited, performing

36

June 25, 2015 CHAPTER 6. DISCUSSION AND CONCLUSION

additional verifications measurements could solve this problem. Although this is consid-ered to be less relevant due to the relative small deviation and it will not be needed forthe evaluation of the leakage levels. The final standard deviation of the model is in anacceptable range compared to other models [12][24][25].

In the final implementation of the leakage simulation tool, multiple leakage sourcesare implemented. These leakages are simulated separately and combined with fully con-structive interference in order to evaluate the largest potential signal power at any givenpoint of the simulated environment.

6.2 Requirement Evaluation

At the start of the project, requirements were set in order to evaluate the results. Thissection will evaluate the requirements.

6.2.1 Pre-study Requirement Evaluation

In Table 6.1 the requirements of the pre-study are evaluated.

Table 6.1: Analysis of Pre-study requirements

No. Comment

1 The major leakage contributors were investigated in order to simulate the leak-age.

2 The MIL-STD-461F standard and guidelines from Stralsakerhetsmyndighetenwere used to evaluate potential risks of the leakage.

3 Indoor propagation models and modelling methods were investigated. A directpath modelling method was used to implement the path loss model.

4 Appropriate measurement methods were used to determine the aspects neededfor the model.

5 The Matlab programming was investigated when needed and applied in theleakage simulation tool.

37


6.2.2 Model Requirement Evaluation

In Table 6.2 the requirements of the model are evaluated.

Table 6.2: Analysis of Model requirements

No. Comment

6 The model was implemented in the leakage simulation tool using Matlab.7 The leakage simulation tool has adjustable parameters for different environ-

ments.8 The leakage simulation tool has adjustable frequency setting.9 A user mappable environment has been implemented in the leakage simulation

tool.10 The leakage simulation tool is able to assign three independent leakage sources

at one given frequency.11 An analysis of the verification measurements has been performed to give the

total accuracy of the given model. This is not implemented in the leakagesimulation tool.

12 The leakage simulation tool does not alert the user when there is a potentialsecurity risk. This feature has not been implemented.

13 The leakage simulation tool will alert the user when the signal strength is abovea set level.

14 The leakage simulation tool is implemented with a graphical user interface withall appropriate assignable parameters.

6.2.3 Measurement Requirement Evaluation

In Table 6.3 the requirements of the measurements are evaluated.

Table 6.3: Analysis of Measurement requirements

No. Comment

15 The equipment used for the measurements are of high quality and precision.16 The orientation and placement of the measurement equipment have been con-

sidered and is defined in the individual experiments.17 The elevation of the measurement equipment have been considered and the

method is defined in the individual experiments.18 Two frequencies have been investigated for the model.

38


6.2.4 Project Requirement Evaluation

In Table 6.4 the requirements of the project are evaluated.

Table 6.4: Analysis of Project requirements

No. Comment

19 Written report is in the form of the current document.20 Weekly meetings have not been performed, but meeting has been performed per

need basis during the project.21 Monthly written report have not been performed, but reports have been per-

formed per need basis during the project.22 Presentation of the results and the leakage simulation have been scheduled at

both Ericsson and LiU.

39


6.3 Conclusion

The purpose of the project was to investigate the leakage from the MINI-LINK setup inthe Ericsson test lab. This was accomplished with an empirical path loss model for thelab environment. This model is adjusted for frequencies and an environment that hasnot earlier been documented, as indicated by the initial pre-study. The path loss modelis adapted to the environment with an empirical derived characteristics of the path lossand object attenuation.

Path loss modelling is an appropriate method to evaluate different leakage scenarios,if the model is able to accurately represent the environment. The deviation of the modelused is important when the worst case scenarios are being evaluated. In the worst casescenario the simulated power will have to be increased by 2σ, or 16 dB for the path lossmodels constructed by this project. This additional contribution will cover over 95% ofthe possible leakage levels that the model will provide and give an accurate representationof the worst case scenario.

It was found that the most likely component to cause the majority of the signal leakagewas the SMA connectors of the MINI-LINK radio units. In the worst case scenario it wasfound that the radiated power was below the limit by both Stralsakerhetsmyndighetenand the MIL-STD-461F standard. Additionally a signal at this frequency attenuatessignificantly over distance and will not pose a potential security risk. However the sim-ulation tool will alert the user if the signal level is above a set limit anywhere in thesimulation environment.

Signal transfer at microwave frequencies are more sensitive. In order to prevent sig-nal leakage from the systems using microwave frequency signals, proper assembly withappropriate tools are essential. It was shown that not connecting the equipment appropri-ately may cause increased signal leakage and additional RF problems such as impedancemismatch and signal reflection.

40


6.4 Future Work

Evaluating the fitted data compared to the final model, it was found that there wasan offset. Investigating an additional frequency in the 18.0 to 26.5 GHz range wouldgive more information how to introduce an adjustment factor to the model. Collectingadditional data for each experiment will likely improve the overall accuracy of the model.The measurements can be performed in different test lab layout to further increase thevalidity of the model.

Additional development of the leakage simulation tool can be performed to improvethe usability. Implementing features such as creating and recalling user defined presetsand layouts is a possible future development.

41

Bibliography

[1] D. Pozar, Microwave and RF Design of Wireless System, John Wiley & Sons, 2001,ISBN: 978-0-471-32282-5

[2] A. Goldsmith, Wireless Communications, Cambridge University Press, 2005,ISBN: 978-0-521-83716-3

[3] S. Haykin, M. Moher, Modern Wireless Communications, Pearson Prentice Hall,2005, ISBN: 0-13-022472-3

[4] K. Fujimoto , Mobile Antenna Systems Handbook, Third Edition, Artech House Inc.,2008, ISBN: 978-1-59693-126-8

[5] K. Wahlin, Tillampad statistik - en grundkurs, Bonnier Utbildning, 2011, ISBN:978-91-523-0718-2

[6] A.H. Systems Inc., Antenna Factor Data, Calibration and parameter data document

[7] I. Dey, G. Messier, S. Magierowski, Joint Fading and Shadowing Model for Large

Office Indoor WLAN Environments, IEEE Transactions on Antennas and Propa-gation, Vol. 62, No. 4, April 2014, Online: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6710174, Read: 2015-03-09

[8] Ericsson AB, Ericsson to build three Global ICT Centers, Press Release 2013, Online:http://www.ericsson.com/news/1726568, Read: 2015-03-02

[9] Ericsson AB, Microwave Towards 2020, 2014, Online: http://archive.ericsson.net/service/internet/picov/get?DocNo=19/28701-FGB101004&Lang=EN&

HighestFree=Y, Read: 2015-03-09

[10] Ericsson AB, Technical Description MINI-LINK PT 2020 ETSI, 2014, Internal Er-icsson document

[11] AWE Communications, Indoor Ray Optical Propagation Models, Online: http://

awe-communications.com/Propagation/Indoor/RayOptical/index.htm, Read:2015-03-09

[12] International Telecommunication Union, Propagation data and prediction methods

for the planning of indoor radiocommunication systems and radio local area networks

in the frequency range 900 MHz to 100 GHz, 2012, Online: http://www.itu.int/

42

June 25, 2015 BIBLIOGRAPHY

dms_pubrec/itu-r/rec/p/R-REC-P.1238-7-201202-I!!PDF-E.pdf, Read: 2015-03-02

[13] European Commission, COST Action 231, Digital mobile radio towards future gen-

eration systems, Final report, 1999, p. 176 - 179.

[14] Information Society Technologies, WINNER II interim channel models, 2007,Online: http://www.cept.org/files/1050/documents/winner2%20-%20final%

20report.pdf, Read: 2015-03-02

[15] DEPARTMENT OF DEFENSE INTERFACE STANDARD, REQUIREMENTS

FOR THE CONTROL OF ELECTROMAGNETIC INTERFERENCE CHARAC-

TERISTICS OF SUBSYSTEMS AND EQUIPMENT, Online: http://snebulos.

mit.edu/projects/reference/MIL-STD/MIL-STD-461F.pdf, Read: 2015-03-02

[16] Measurementtest.com, How To Measure Antenna Gain, 2010, Online: http://www.measurementest.com/2010/09/how-to-measure-antenna-gain-part-1-gain_

08.html, Read: 2015-04-02

[17] Ohio University, Curve Fitting, Loglog Plots, and Semilog Plots, 2003,Online: https://www.math.ohiou.edu/courses/matlab/math266a/

266A-fitting-logplot.pdf, Read: 2015-04-09

[18] Mathworks, Least-Squares Fitting, Online: http://se.mathworks.com/help/

curvefit/least-squares-fitting.html?refresh=true, Read: 2015-04-09

[19] Stralsakerhetsmyndigheten, Stralsakerhetsmyndighetens forfattningssamling ISSN

2000-0987, Online: http://www.stralsakerhetsmyndigheten.se/Global/

Publikationer/Forfattning/SSMFS/2008/SSMFS2008-18.pdf, Read: 2015-04-24

[20] A.H. Systems Inc., TYPICAL CONVERSION FORMULAS, Online: http://www.ahsystems.com/notes/TYPICAL_CONVERSION_FORMULAS.pdf, Read: 2015-04-24

[21] Harbour Industries, Shielding Effectiveness Test Method, Online: http:

//harbourind.com/harbourdev/images/technical_pdfs/shielding_

effectiveness_test_method.pdf, Read: 2015-05-05

[22] Tect Electronics, The Waveguide Solution, Online: http://www.

tect-electronics.com/uploads/files/TWS/Flexible_Waveguide.pdf, Read:2015-05-07

[23] Applied Engineering Products, SMA Series Subminiature RF Connectors, p. 3, On-line: http://www.radiall.com/media/AEP%20SMA%20127-1.pdf, Read: 2015-05-07

[24] K. Cheung, J. Sau, R. D. Murch, A New Empirical Model for Indoor Propagation

Prediction, IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 47,NO. 3, AUGUST 1998, Online: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=704854, Read: 2015-05-22

43

June 25, 2015 BIBLIOGRAPHY

[25] A. Valcarce, J.Zhang, Empirical Indoor-to-Outdoor Propagation Model for Residen-

tial Areas at 0.9–3.5 GHz, IEEE ANTENNAS AND WIRELESS PROPAGATIONLETTERS, VOL. 9, 2010, Online: http://ieeexplore.ieee.org/stamp/stamp.

jsp?arnumber=5510104, Read: 2015-05-22

44

Appendices

45

Appendix A

Plotted Measured Data

A.1 Open Space Plot for 23.0 GHz

Figure A.1: Measured data for open space at 23.0 GHz

46

June 25, 2015 APPENDIX A. PLOTTED MEASURED DATA

A.2 Open Space Plot for 18.0 GHz

Figure A.2: Measured data for open space at 18.0 GHz

A.3 Rack Environment Plot for 23.0 GHz

Figure A.3: Measured data for rack environment at 23.0 GHz

47

June 25, 2015 APPENDIX A. PLOTTED MEASURED DATA

A.4 Rack Environment Plot for 18.0 GHz

Figure A.4: Measured data for rack environment at 18.0 GHz

48

Appendix B

Raw data

B.1 Path Loss Exponent Measurements

1 %Path Loss Exponent Measurements2

3 %Distance4 d = [1 1 .5 2 2 .5 3 3 .5 4 4 .5 5 5 .5 6 6 .5 7 7 .5 8 8 .5 9 9 .5 1 0 ] ;5

6 % Col l e c t ed data7 %Measurement s e r i e s 1−58 %18 GHz9 S1 = [−48.2 −51.7 −53.2 −53.5 −56.6 −58.1 −56.4 −60.9 −59.3 −61.9 −61.0

−60.8 −65.4 −62.3 −62.3 −64.7 −65.0 −69.1 −64 .8 ] ;10 S2 = [−47.3 −50.7 −52.7 −54.1 −55.6 −57.3 −56.7 −57.6 −60.8 −66.5 −65.4

−60.6 −64.5 −62.6 −62.3 −63.7 −67.0 −68.0 −67 .4 ] ;11 S3 = [−45.5 −50.0 −52.7 −52.9 −53.8 −57.6 −56.7 −61.3 −58.2 −59.6 −62.8

−61.0 −62.0 −62.0 −60.8 −63.2 −67.1 −63.8 −67 .8 ] ;12 S4 = [−46.3 −49.3 −50.4 −52.4 −53.6 −56.4 −56.0 −58.2 −61.7 −62.4 −61.8

−60.4 −62.6 −62.0 −60.8 −61.5 −65.2 −64.3 −70 .8 ] ;13 S5 = [−47.0 −49.9 −50.3 −51.6 −53.4 −54.7 −54.4 −55.4 −57.6 −58.2 −59.2

−61.7 −64.1 −63.0 −59.6 −66.2 −61.0 −64.2 −71 .5 ] ;14

15 %23 GHz16 S1 = [−51.0 −55.7 −60.3 −61.2 −61.5 −63.2 −62.1 −63.0 −65.0 −68.0 −64.7

−69.8 −65.0 −69.3 −72.4 −73.8 −76.9 −72.3 −71 .6 ] ;17 S2 = [−51.4 −56.0 −58.1 −63.6 −61.4 −61.0 −62.9 −64.7 −66.0 −67.0 −70.0

−66.4 −71.3 −68.8 −67.8 −69.7 −66.6 −67.2 −69 .3 ] ;18 S3 = [−48.9 −51.6 −52.9 −59.9 −60.2 −57.9 −59.1 −61.4 −62.4 −67.8 −65.2

−67.8 −66.9 −66.4 −66.7 −73.3 −63.5 −65.7 −67 .8 ] ;19 S4 = [−47.8 −51.8 −53.9 −56.4 −59.0 −58.0 −60.8 −62.1 −64.0 −63.1 −65.4

−64.3 −61.4 −68.9 −62.7 −65.0 −64.3 −64.9 −65 .6 ] ;20 S5 = [−47.6 −52.6 −54.3 −55.6 −59.5 −59.3 −60.0 −59.9 −65.6 −60.9 −64.6

−65.3 −63.4 −62.5 −64.4 −63.6 −62.8 −67.4 −66 .8 ] ;

49

June 25, 2015 APPENDIX B. RAW DATA

B.2 Verification Data Measurements

1 %Ve r i f i c a t i o n Data Measurements2 %Received power measurements with Pt = 0 dBm, 2 m between each po int in the

matrix3

4

5 %23 GHz6 S1 = [−72.7 −82.2 −79.0 −68.7 −70.3 −86.0 −79.0;7 −77.0 NA NA −69.8 NA NA −75.6;8 −64.3 −72.7 NA −65.3 NA −75.2 −83.2;9 −60.2 −66.8 NA −57.7 NA −72.7 −85.4;

10 −69.6 −68.7 RAU −66.3 NA −75.0 −80.5;11 −56.8 −55.8 −56.2 −57.5 NA −65.3 −77.6;12 −59.6 −64.2 −56.8 −59.7 −63.0 −64.8 −77.3;13 −66.3 −66.3 −57.6 −73.0 −58.7 −62.8 −73.8;14 −64.6 NA NA −66.1 NA NA −71.5;15 −81.9 −82.6 −74.4 −66.4 −66.8 −78.2 −87 . 0 ; ] ;16

17 %18 GHz18 S2 = [−67.4 −83.0 −75.0 −77.9 −79.9 −86.7 −86.5;19 −65.0 NA NA −65.1 NA NA −82.8;20 −68.7 −73.9 NA −63.1 NA −72.1 −86.5;21 −59.3 −65.0 NA −62.1 NA −70.9 −86.5;22 −65.4 −67.0 RAU −62.3 NA −71.3 −86.5;23 −60.9 −52.5 −50.8 −57.7 NA −67.6 −80.3;24 −57.5 −55.5 −56.8 −66.0 −63.9 −65.9 −79.9;25 −75.9 −65.8 −60.7 −60.2 −62.7 −63.4 −78.0;26 −63.7 NA NA −60.9 NA NA −76.8;27 −79.7 −83.2 −71.9 −67.9 −67.4 −75.2 −83 . 5 ; ] ;

50


B.3 RAF measurements

1 %RAF Measurements2

3 %Measuring cond i t i on s4 Wr = 1 . 2 ; %rack width5 Sep = 2 . 0 ; %RX−TX sepa ra t i on6 Ht = 1 . 0 9 ; %t ran smi t t e r he ight7 Hr = [ 0 . 6 0 .7 0 .8 0 . 9 1 . 0 1 .1 1 .2 1 . 3 1 . 4 1 .5 1 . 6 ] ; %r e c e i v e r he ight8

9 %Measured va lue s10 %X SN [ i ] cor re sponds to measured value at he ight Hr [ i ]11

12 % 23 GHz13 %Pr , l i g h t l y densed rack14 L S1 = [−63.9 −64.1 −58.7 −56.2 −54.6 −56.7 −57.3 −60.3 −61.2 −68.5 −65 .0 ] ;15 L S2 = [−67.8 −72.9 −63.8 −56.5 −60.0 −61.2 −61.4 −57.3 −57.0 −56.9 −62 .9 ] ;16 L S3 = [−71.2 −60.6 −70.0 −57.4 −63.4 −63.1 −59.6 −61.5 −58.0 −54.2 −57 .9 ] ;17

18 %Pr , medium densed rack19 M S1 = [−74.5 −58.0 −60.3 −63.5 −63.4 −57.1 −55.8 −52.9 −56.8 −57.2 −58 .6 ] ;20 M S2 = [−65.6 −60.8 −60.3 −64.5 −59.1 −58.4 −58.8 −60.0 −57.0 −61.4 −72 .0 ] ;21 M S3 = [−83.3 −74.4 −79.3 −76.5 −61.9 −63.1 −65.0 −69.2 −59.6 −61.2 −63 .9 ] ;22

23 %Pr , heavy densed rack24 H S1 = [−86.5 −83.0 −81.5 −82.6 −85.5 −80.2 −83.5 −80.0 −79.5 −83.5 −75 .8 ] ;25 H S2 = [−82.5 −89.5 −87.0 −82.5 −82.5 −76.2 −90.0 −77.2 −75.9 −76.1 −76 .7 ] ;26 H S3 = [−71.3 −77.9 −75.8 −81.5 −80.8 −75.3 −71.8 −67.9 −76.9 −71.4 −65 .9 ] ;27

28 % 18 GHz29 %Pr , l i g h t l y densed rack30 L S1 = [−58.2 −58.3 −58.4 −52.2 −58.6 −62.9 −60.3 −58.3 −64.9 −65.0 −74 .5 ] ;31 L S2 = [−70.5 −60.8 −58.4 −53.3 −66.8 −51.9 −56.8 −57.0 −56.0 −52.0 −57 .2 ] ;32 L S3 = [−61.3 −68.5 −69.8 −65.9 −56.8 −59.3 −67.5 −66.5 −66.7 −63.0 −65 .2 ] ;33

34 %Pr , medium densed rack35 M S1 = [−76.0 −66.9 −69.5 −61.0 −65.1 −58.2 −69.8 −62.8 −64.9 −58.9 −65 .0 ] ;36 M S2 = [−64.8 −77.5 −62.6 −56.4 −59.8 −70.0 −66.0 −65.0 −60.1 −59.8 −67 .0 ] ;37 M S3 = [−69.5 −75.5 −69.5 −68.5 −57.8 −65.8 −66.5 −68.3 −69.5 −63.3 −61 .9 ] ;38

39 %Pr , heavy densed rack40 H S1 = [−68.5 −70.5 −81.5 −70.9 −65.0 −63.4 −65.2 −67.1 −83.2 −71.5 −60 .3 ] ;41 H S2 = [−64.0 −72.7 −69.5 −67.8 −72.5 −73.0 −76.0 −88.5 −80.5 −75.0 −73 .8 ] ;42 H S3 = [−87.0 −71.5 −82.5 −77.5 −74.0 −69.5 −82.0 −73.8 −74.0 −78.0 −71 .5 ] ;

51


B.4 Solid Object Attenuation Measurements

1 %So l i d Object Attenuation Measurements2

3 %Measuring cond i t i on s4 Wct = 0 . 9 ; %coo l i n g tower width5 Sep1 = 2 .0 + Wct ; %RX−TX sepa ra t i on6 Sep2 = 4 .0 + Wct ; %RX−TX sepa ra t i on7 Sep3 = 6 .0 + Wct ; %RX−TX sepa ra t i on8 Disp = [−1.5 −1.2 −0.9 −0.6 −0.3 0 . 0 0 .3 0 .6 0 . 9 1 . 2 1 . 5 ] ; %RX−TX

disp lacement9

10 % 23 GHz11 %measured r e c e i v ed power , SN measurement correspond to SepN and12 %SN[ i ] to d i sp [ i ]13 S1 = [−85.6 −85.0 −91.0 −96.0 −92.0 −85.9 −88.3 −91.2 −93.1 −88.7 −91 .0 ] ;14 S2 = [−91.0 −94.0 −91.0 −90.0 −92.0 −93.0 −93.0 −90.0 −89.6 −90.8 −85 .7 ] ;15 S3 = [−83.6 −86.0 −93.0 −86.5 −84.0 −83.7 −90.0 −85.0 −91.0 −86.7 −79 .5 ] ;16

17 % 18 GHz18 %measured r e c e i v ed power , SN measurement correspond to SepN and19 %SN[ i ] to d i sp [ i ]20 S1 = [−75.6 −76.9 −80.5 −83.0 −86.0 −87.0 −84.0 −79.0 −82.5 −79.6 −85 .9 ] ;21 S2 = [−80.0 −84.3 −79.0 −85.0 −82.7 −85.6 −91.0 −82.0 −87.0 −85.7 −77 .8 ] ;22 S3 = [−74.2 −77.3 −74.8 −82.6 −86.0 −84.0 −79.6 −77.9 −80.0 −81.6 −87 .0 ] ;

52

Appendix C

Leakage Simulation Tool: User

Guide

Introduction

The Leakage Simulation Tool allows the user to simulate and evaluate potential leakagelevels in a 2D environment. The simulation can be defined by the user by using thecustomizable options or use one of the the predefined options. The layout of the leakagesimulation tool can be seen in Figure C.1.

Figure C.1: Default layout of the leakage simulation tool

53

June 25, 2015 APPENDIX C. LEAKAGE SIMULATION TOOL: USER GUIDE

Simulation Setup

This section will define the different simulation options available in the leakage simulationtool.

Preset Model

The preset mode allows the user to quickly simulate different leakage scenarios, allowingthe user to focus on their simulation environment. The preset mode is limited to twofrequency configurations, which can be selected from the pop-down menu in the Pre-

set Model -panel. The preset mode contains empirically derived constants for the givenfrequencies.

User Defined Model

Simulating frequencies other than the ones found in the Preset mode can be done in theUser configurable mode. The frequency, path loss exponent and the attenuation constantscan be defined. The frequency is defined in GHz, and the RAF constants is defined indB/m.

Room Properties

The simulation environment is defined by the Room Properties panel. Configuring thesize of the simulation environment is done by defining the length, width and resolutionof the environment. The length and width are defined in meters and the resolution canbe set to a 0.3x0.3 or a 1.0x1.0 meter grid resolution.

Leakage Source Properties

The leakage source properties allows the user to define one to three leakage sources byselecting the number of sources from the pop-down menu. The location of each source isdone by configuring its x- and y-coordinates in the simulation environment. Each leakagepower can be configured individually and is defined in dBm.

54

June 25, 2015 APPENDIX C. LEAKAGE SIMULATION TOOL: USER GUIDE

Layout Generation

After the configurable parameters have been set the environment can be generated bypressing the Generate Simulation Condition-button. The simulation environment will beupdated and the user can configure the placement of the different objects. Firstly thelightly populated racks are placed in the environment by left-clicking in the configuredgrid. When all locations are marked for each specific density press the Enter key andthe marked points in the grid will turn gray. This procedure is now repeated for mediumand heavily populated rack and finally for solid objects. An environment with light andmedium racks already configured and the heavy rack being marked can be seen in FigureC.2.

Figure C.2: Simulation environment configuration in progress

With all the objects placed, the program will simulate the configured leakage scenarioand display it in the simulation environment. If multiple sources are simulated the leakagepower contribution from each source is assumed to be fully constructive. If the leakagelevels at any location exceed -10 dBm the program will alert it with a warning in a pup-up window. This is an indication that the signal leakage might interfere with equipmentin the vicinity. The user must keep in mind the standard deviation of the model used inorder to properly evaluate the leakage levels, since the leakage simulation tool does notconsider the deviation.

55

Documents

Indoor propagation modelling at microwave frequencies in a ...liu.diva-portal.org/smash/get/diva2:838835/FULLTEXT01.pdfa high capacity microwave telecommunication system called MINI-LINK