Enhancing Location Estimation Accuracy Using Cooperative Relay Station In WiMAX.

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ENHANCING LOCATION ESTIMATION ACCURACY USING COOPERATIVE RELAY STATION IN WIMAX

YIT SIN NEE

A report submitted in partial fulfilment of the requirements for the degree of Bachelor of Electronic Engineering (Telecommunication Electronics) with Honours

Faculty of Electronic and Computer Engineering UNIVERSITI TEKNIKAL MALAYSIA MELAKA

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UNIVERSTI TEKNIKAL MALAYSIA MELAKA

FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER

BORANG PENGESAHAN STATUS LAPORAN

PROJEK SARJANA MUDA II

Tajuk Projek : ………

Sesi

Pengajian :

Saya ……….. (HURUF BESAR)

mengaku membenarkan Laporan Projek Sarjana Muda ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut:

1. Laporan adalah hakmilik Universiti Teknikal Malaysia Melaka.

2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja.

3. Perpustakaan dibenarkan membuat salinan laporan ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. Sila tandakan ( √ ) :

SULIT* *(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972)

TERHAD** **(Mengandungi maklumat terhad yang telah ditentukan oleh _{organisasi/badan di mana penyelidikan dijalankan)}

TIDAK TERHAD

Disahkan oleh:

__________________________ ___________________________________

(TANDATANGAN PENULIS) (COP DAN TANDATANGAN PENYELIA)

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III

“I declare that this report entitled “Enhancing Location Estimation Accuracy using Cooperative Relay Station in WiMAX” is the result of my own research except as cited

in the references. The report has not been accepted for any degree and is not concurrently submitted in candidature of any other degree.”

Signature : ……….. Name : ……….. Date : ………..

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“I hereby declare that I have read through this report entitled “ENHANCING LOCATION ESTIMATION ACCURACY USING COOPERATIVE RELAY STATION IN WIMAX” and found that it has comply the partial fulfilment for awarding the degree of Bachelor of Electronic Engineering (Telecommunication Electronics) with

Honours.”

Signature : ………. Supervisor’s Name : ……….. Date : ………..

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I dedicate this research work to my dear supervisor, Dr. Azmi bin Awang Md Isa who has taught and guided me throughout this whole year and to my family who supports me

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ACKNOWLEDGEMENT

First and foremost, I would like to express my gratitude to my dear supervisor, Dr. Azmi bin Awang Md Isa for giving the support mentally and physically, by sharing his expertise, knowledge and experience with me. He has always provided me guidance on how my project should work and gave me new idea to be implemented, as well as solutions for some problem.

I would also like to thank to all those time, concern and efforts that were given to me during the whole process of completing this project and report. I am thankful to everyone who always motivate me directly and indirectly during my FYP.

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VII

ABSTRACT

Location and Positioning (L&P) based services plays an important role in wireless communication system. Many researches were done to enhance the location estimation accuracy, but much improvements are yet to be done to satisfy the requirement of Federal Communications Commission (FCC). In wireless communication system, location estimation accuracy can be increased by utilizing more base stations (BS), however there are some restrictions such as high building cost of BS. In this project, a novel technique is developed, where through the usage of relay station (RS) in Worldwide Interoperability for Microwave Access (WiMAX) network, the location estimation accuracy can be enhanced by using only one BS and two RSs. An algorithm including four main parts for locating the coordinates of BSs, RSs and mobile stations (MS), time of arrival (TOA) estimation based on two non-light-of-sight (NLOS) error calibration method, generating the NLOS error using Circular Disk Scatterer Model (CDSM), and calculating the location estimation error using Linear Least Square (LLS) and Non Linear Least Square (NLLS) method. An algorithm to select the suitable RS location is developed as well. Simulation results shown that the location estimation accuracy for the deployment of one BS and two RSs is the best among all the cases. The result obtained will lead to a major development to the location estimation technologies in WiMAX network.

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VIII

ABSTRAK

Perkhidmatan pengenalpastian lokasi dan kedudukan memainkan peranan yang penting dalam sistem komunikasi tanpa wayar. Walaupun banyak kajian telah dijalankan untuk meningkatkan ketepatan lokasi, namun penambahbaikan masih perlu dilakukan untuk memenuhi keperluan Federal Communications Commission (FCC). Dalam sistem komunikasi tanpa wayar, ketepatan lokasi boleh ditingkatkan dengan menggunakan lebih banyak stesen pangkalan, namun halangan-halangan seperti kos pembinaan stesen pangkalan yang tinggi tetap wujud. Melalui projek ini, satu teknik baru telah dibangunkan melalui penggunaan stesen geganti untuk rangkaian Worldwide Interoperability for Microwave Access (WiMAX). Ketepatan lokasi boleh dipertingkatkan menggunakan hanya satu stesen pangkalan dan dua stesen geganti. Pengekodan telah dihasilkan dan dibahagikan kepada empat bahagian utama iaitu mencari koordinat stesen pangkalan, stesen geganti dan stesen mudah alih, menggunakan kaedah time of arrival (TOA) berdasarkan dua cara penentukuran ralat laluan penglihatan yang dihalang, seterusnya menjana ralat laluan penglihatan yang dihalang menggunakan Circular Disk Scatterer Model (CDSM), dan akhirnya mengira ralat anggaran lokasi menggunakan kaedah Linear Least Square (LLS) dan Non Linear Least Square (NLLS). Algoritma pemilihan lokasi stesen geganti yang sesuai juga dibangunkan. Keputusan simulasi menunjukkan bahawa ketepatan anggaran lokasi untuk penggunaan satu stesen pangkalan dan dua stesen geganti adalah terbaik antara semua kes. Keputusan yang diperolehi akan meningkatkan pembangunan teknologi pengenalpastian lokasi dan kedudukan untuk rangkaian WiMAX.

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

PROJECT TITLE I

DECLARATION II

DEDICATION V

ACKNOWLEDGEMENT VI

ABSTRACT VII

ABSTRAK VIII

TABLE OF CONTENTS IX

LIST OF TABLES XIII

LIST OF FIGURES XIV

LIST OF ABBREVIATIONS XVI

1 INTRODUCTION 1

1.1 Introduction 1

1.2 Problem Statement 2

1.3 Project Objective 3

1.4 Project Scope 3

1.5 Contributions of Project 3

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CHAPTER TITLE PAGE

2 LITERATURE REVIEW 5

2.1 Introduction 5

2.2 Overview of WiMAX standards 6

2.3 Location and Positioning (L&P) Techniques 8 2.3.1 MIMO (Multiple Input Multiple Output) 11 2.3.2 Adaptive Modulation and Coding (AMC) 12

2.3.3 Beamforming 13

2.3.4 Relay Station 14

2.4 Estimation of Position Location Parameters 17

2.4.1 TDOA Estimation 18

2.4.2 AOA Estimation 18

2.4.3 TOA Estimation 19

2.5 Location Estimation Algorithms 20

2.6 Geometric Approach 23

2.7 Statistical Approach 24

2.8 Location Accuracy Measurements 28

2.9 Effect of NLOS propagation 28

2.10 Modelling NLOS Errors 30

2.11 Location Estimation Accuracy Technologies 32 2.11.1 A System Engineering Approach to

Improving the Accuracy of Mobile Station Location Estimation

2.11.2 SSSD-based Mobile Positioning: On the Accuracy Improvement Issues in Distance and Location Estimations

2.11.3 Mobile Positioning Based on Relaying Capability of Mobile Stations in Hybrid Wireless Network

2.11.4 Positioning Techniques Comparison 35

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CHAPTER TITLE PAGE

3 METHODOLOGY 36

3.1 Introduction 36

3.2 Flow Chart 37

3.3 Classification of Propagation Scenario Related to RS

3.4 System Model 39

3.5 Multipath Fading Models – WINNER Multipath Fading Model

3.6 Coordinate of Base Station, Mobile Station and Relay Station

3.7 TOA Estimation based on Mean/Maximum Access Delay/Delay Spread

3.8 Delay Spread and Maximum Excess – Delay Distribution

3.9 Calculate NLOS Error based on CDSM 48 3.10 Calculate Location Estimation Error 49 3.11 Selecting the Suitable RS Location 49

3.12 Investigation of GDOP Effects 50

3.13 Summary 53

4 RESULT AND DISCUSSION 54

4.1 Introduction 54

4.2 Result 55

4.3 Summary 64

5 CONCLUSION AND RECOMMENDATION 65

5.1 Conclusion 65

5.2 Recommendation 66

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XII

CHAPTER PAGE

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XIII

LIST OF TABLES

TABLE TITLE PAGE

2.1 Receiver SNR Assumptions 13

2.2 Comparison of Positioning Techniques 35

3.1 Tapped Delay-Line Model for Scenario 1 41

3.2 Tapped Delay-Line Model for Scenario 2 42

3.3 Tapped Delay-Line Model for Scenario 3 42

3.4 Maximum Error based on Propagation Scenario 47 3.5 Mean Access Delay under Urban Environment for

Different Propagation Scenario

4.1 Propagation Scenarios 55

4.2 (a) RMSE under different propagation scenarios and different cases using Maximum Delay Spread

(b) RMSE under different propagation scenarios and different cases using Mean Access Delay

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XIV

LIST OF FIGURES

FIGURE TITLE PAGE

2.1 System Architecture of L&P in WiMAX Services 11

2.2 WiMAX BS with assisted RS 17

2.3 Network Architecture for (a) Conventional WiMAX (b) MMR

2.4 Relay Network 21

2.5 System Model of RS 22

2.6 Trilateration based on TOA 23

2.7 TOA Data Fusion 24

2.8 NLOS Propagation in Wireless Environments 29

2.9 Geometry of CDSM 31

2.10 Flooding procedure 34

3.1 Project Flow Chart 38

3.2 Proposed Location Estimation using MR-BS with assisted RS 40

3.3 Coordinates of BS, MS and RS 44

3.4 Example of average power delay profile 45

3.5 GDOP Contours using 3 TOA measurements for 3 BS 51 3.6 (a) GDOP Contours Using 3 BS with assisted of 1 RS 52 (b) GDOP Contours Using 3 BS with assisted of 2 RS 52

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FIGURE TITLE PAGE

4.1 (a) The CDF of location estimation error for Propagation Scenario 1 (used Maximum Delay Spread)

(b) The CDF of location estimation error for Propagation Scenario 1 (used Mean Access Delay)

4.2 (a) The CDF of location estimation error for Propagation Scenario 2 (used Maximum Delay Spread)

(b) The CDF of location estimation error for Propagation Scenario 2 (used Mean Access Delay)

4.3 (a) The CDF of location estimation error for Propagation Scenario 3 (used Maximum Delay Spread)

(b) The CDF of location estimation error for Propagation Scenario 3 (used Mean Access Delay)

4.4 (a) The CDF of location estimation error for BS and 2 RSs under different propagation scenarios (used Maximum Delay Spread)

(b) The CDF of location estimation error for BS and 2 RSs under different propagation scenarios (used Mean Access Delay)

4.5 Location Estimation Error at 3 BSs and Different Number of RSs using Two NLOS Error Calibration Method

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XVI

LIST OF ABBREVIATIONS

L&P - Location and Positioning BS - Base Station

MS - Mobile Station

GDOP - Geometric Dilution of Precision TOA - Time of Arrival

NLOS - Non-line of Sight RS - Relay Station

WiMAX - Worldwide Interoperability for Microwave Access LBS - Location based Services

PSAP - Public Safety Answering Point QoS - Quality of Service

3G - Third Generation

WLAN - Wireless Local Area Network IP - Internet Protocol

MIMO - Multiple Input Multiple Output AMC - Adaptive Modulation and Coding LOS - Line of Sight

RF - Radio Frequency

GPS - Global Positioning System

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XVII

TTFF - Time to First Fix MSR - Mobile Scan Report

RSSI - Received Signal Strength Indication RTD - Round-trip Delay

RD - Relative Delay

D-TDOA - Downlink Time Difference of Arrival U-TDOA - Uplink Time Difference of Arrival CSN - Connectivity Service Network CPE - Customer Premises Equipment NMS - Network Management Systems

OFDMA - Orthogonal Frequency Division Multiple Access QAM - Quadrature Amplitude Modulation

BPSK - Binary Phase Shift Keying SNR - Signal to Ratio

MAC - Media Access Control

MCS - Modulation and Coding Scheme DOA - Direction of Arrival

OPEX - Operational Expenditure QoE - Quality of End-user TCO - Total Cost of Ownership

NGMN - Next Generation Mobile Network CINR - Carrier to Interference and Noise Ratio MR - Multihop Relay

TDOA - Time Difference of Arrival RSS - Received Signal Strength AOA - Angle of Arrival

LLS - Linear Least Square NLLS - Non Linear Least Square ARS - Ad hoc Relay Station

CDSM - Circular Disk Scatterer Model

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XVIII

PD - Pseudorange PL - Position Location

WINNER - Wireless World Initiative New Radio EM - Electromagnetic

PDP - Power Delay Profile

CDP - Cumulative Distribution Probability FCC - Federal Communications Commission RMSE - Root Mean Square Error

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CHAPTER 1

INTRODUCTION

1.1 Introduction

Due to the significant growth of wireless networks, Location & Positioning (L&P) techniques act as an important role as this techniques are required to be carried out before a connection can be established. L&P method relies on availability and the coverage region of base station (BS) locations as well as the mitigation of propagation effects [1]. The ability of a mobile station (MS) to send and receive signal as well as determining their location depends greatly on the BS [2]. It is however, the location accuracy suffers from poor geometric dilution of precision (GDOP) caused by BS location as the orthodox algorithms result in large GDOP values which correspond to poor geometrical topology [3]. Furthermore, a large error in time of arrival (TOA) reading occurs as a result of non-line of sight (NLOS) effect [4]. The reception of an area becomes poor due to obstruction and random fading or may even turn outs to be a dead zone, hence affecting MS estimation

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accuracy [5]. Relay station (RS) is used to extend the coverage of a single BS [6]. A MS can connect to a BS by transmitting signal to RS first, then RS will relay the signal to the BS. Besides enhancing the throughput, RS can also be used for positioning purposes.

In this project, fixed relay station based on Worldwide Interoperability for Microwave Access (WiMAX) cellular network architecture is used to extend the coverage of a single BS and to enhance the location estimation accuracy. A novel mobile location method based on assistance of relay stations using TOA measurements to mitigate the effect of NLOS in a WiMAX network is proposed. The main contribution of this project is a proposed algorithm that allow significant improvement in location estimation accuracy without additional base station on network architecture.

1.2 Problem Statement

Poor GDOP caused by BS location will lower the location estimation accuracy. GDOP is a metric to determine the geometric effect on the accuracy of location estimation for the MS. A high value of GDOP will degrade the performance of location estimation [3]. Besides, NLOS effect in the coverage region deteriorates the location estimation accuracy. NLOS effect is common where obstacles present between the BS and MS such as forests, hills and buildings [4]. Apart from this, the building cost of BS is very high due to the high cost to pay for antenna space, the wired backhaul connection and the digital and radio frequency equipment [7]. Moreover, the design of BS is more complex than RS as it has more functionality [8]. However, in this case the main aim is to extend the coverage range of a BS and enhance the location estimation accuracy. Hence, building a RS is enough.

In this project, a single base station is used. Relay stations serve as base station to mobile station and to be a mobile station for base station. By replacing base stations with several relay stations, the functionalities can still work and the cost will be lower under comparison.

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1.3 Project Objective

The objective of this project are listed below:

1) To propose a novel RS technique to improve the conventional L&P algorithms by considering the geometric effect on location estimation accuracy.

2) To develop algorithm for simulation of the proposed technique.

3) To incorporate the developed algorithm into WiMAX specification and evaluate the performance of the algorithm.

1.4 Project Scope

In this project, several scopes have been identified. First and foremost, a RS system model is being developed. After that, the coverage and location estimation accuracy of a BS region is being tested. Next, an algorithm is produced using MATLAB. After that, the ideal location to build RS is determined. The number of relay station to be installed is also analyzed. Different parameters are tested to minimize the system’s limitation. The results will be shown in MATLAB software. Hardware is not available.

1.5 Contributions of Project

This project is focused on the enhancement for determination of the MS’s location, based on WiMAX technology, by employing the usage of RS. The contribution of this project can be summarized as follows:

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• Introduction of a novel RS technique to improve the conventional L&P algorithms by considering the geometric effect on location estimation accuracy.

• Development of algorithm for simulation based on geometrical approach and statistical approach by using TOA as range measurements to enhance location estimation in various NLOS conditions.

• Incorporation of the developed technique into WiMAX specification. • Evaluation for the performance of the algorithm.

1.6 Structure of Project

The remainder of this thesis is organized as follow. Chapter 2 comprise of the literature review which presents the background knowledge for the main contributions of this thesis. Generally, in Chapter 2, the WiMAX technology and L&P are reviewed. Several features of WiMAX that can be used are also highlighted. The geometric and statistical approach used are presented as well. Besides, the effect of NLOS propagation is presented. Finally, the chapter reviews and compares the current existing technology to enhance location estimation accuracy.

Then, Chapter 3 provides the methodology and the steps involved in developing the algorithm of the proposed technique. A novel technique using RS to enhance the location estimation accuracy based on different propagation scenarios is demonstrated. The specification of WiMAX employed to form the algorithm through a measurement model which then includes TOA data fusion and existing linear least square (LLS) calculation are presented.

Next, Chapter 4 explains the result and discussion from the evaluation of simulations. Lastly, Chapter 5 concludes the project and proposes some recommendations for future work.

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CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

In this chapter, literature reviews that are related to the project’s objective will be discussed. In order to complete this project, various journals and articles were studied and reviewed, including the existing location and positioning techniques and relay station based WiMAX cellular network architecture. Several journals of previous research project which are related with this project’s purpose and objective were discussed and compared.

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2.2 Overview of WiMAX standards

Location based services (LBS) have evolved into a vital features for most wireless networks. There are significant demand for LBS such as navigation, assets tracking, public safety wireless location, location sensitive billing, fleet operations, intelligent transportation, mobility management, lawful interception, battle against cellular phone fraud, wireless system design, efficient radio resource management and emergency services such as E911, where the location of users are reported to the public safety answering point (PSAP) and emergency rescuers are dispatched to that specific location [9][10][11].

WiMAX, known as Worldwide Interoperability for Microwave Access, is based on the IEEE802.16 standard. The members of WiMAX forum oversees the promotion of WiMAX through activities such as implementing bandwidth licensing policies and testing to ensure interoperability between equipment from different vendors [8]. Research in wireless broadband networks has also gaining more attentions in many fields including allocation of resources, placement of relays, handover between cells, Quality of Service (QoS) and others. Dozens or even hundreds of pilot networks are deployed worldwide to test drive the WiMAX technology [12]. WiMAX wireless technology may be complementary to existing 3G, WLAN and wired broadband networks. In some perspectives, WiMAX technology has the potential of threatening existing markets [13].

Location based services helps to determine and deliver users’ location to applications on the network or device, which can in turn add value by personalizing services for their subscribers [10]. The three main usage categories for location services in WiMAX are:

a) Commercial LBS, connected with applications providing value-added services to the subscribers of those services through knowledge of the MS location. These applications sums up to two types:

i. Push type services, in which location request is started by an entity on network side, such as local advertisements.

ii. Pull type services, where a request for location is activated by an application on the MS side, such as an MS request for local places.

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CHAPTER 1

INTRODUCTION

1.1 Introduction

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1.2 Problem Statement

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1.3 Project Objective

The objective of this project are listed below:

1) To propose a novel RS technique to improve the conventional L&P algorithms by considering the geometric effect on location estimation accuracy.

2) To develop algorithm for simulation of the proposed technique.

3) To incorporate the developed algorithm into WiMAX specification and evaluate the performance of the algorithm.

1.4 Project Scope

1.5 Contributions of Project

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• Introduction of a novel RS technique to improve the conventional L&P algorithms by considering the geometric effect on location estimation accuracy.

• Development of algorithm for simulation based on geometrical approach and statistical approach by using TOA as range measurements to enhance location estimation in various NLOS conditions.

• Incorporation of the developed technique into WiMAX specification. • Evaluation for the performance of the algorithm.

1.6 Structure of Project

Next, Chapter 4 explains the result and discussion from the evaluation of simulations. Lastly, Chapter 5 concludes the project and proposes some recommendations for future work.

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CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

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2.2 Overview of WiMAX standards

a) Commercial LBS, connected with applications providing value-added services to the subscribers of those services through knowledge of the MS location. These applications sums up to two types:

i. Push type services, in which location request is started by an entity on network side, such as local advertisements.

ii. Pull type services, where a request for location is activated by an application on the MS side, such as an MS request for local places.

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