Design and analysis of LTE-WLAN wireless router with QOS preservation.

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Faculty of Electronic and Computer Engineering

DESIGN AND ANALYSIS OF LTE-WLAN WIRELESS

ROUTER WITH QOS PRESERVATION

Abdulaziz Mohammed Saleh Ghaleb

MASTER OF SCIENCE IN ELECTRONIC ENGINEERING

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DESIGN AND ANALYSIS OF LTE-WLAN WIRELESS ROUTER WITH QOS PRESERVATION

Abdulaziz Mohammed Saleh Ghaleb

A thesis submitted

in fulfillment of the requirements for the degree of Master of Science in Electronic Engineering

Faculty of Electronic and Computer Engineering

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

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DECLARATION

I hereby declare that this thesis entitle “Design and analysis of LTE-WLAN wireless router with QoS preservation” is the result of my own research except for works that have been cited clearly in the references. The thesis has not been accepted for any degree and is not concurrently submitted in candidature of any other degree.

Signature : ………

Name : Abdulaziz Mohammed Saleh Ghaleb

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APPROVAL

I hereby declare that I have read this report and in my opinion this report is sufficient in terms of scope and quality for the award of Master of Science in Electronic Engineering.

Signature : ………

Supervisor’s Name : Dr. Lim Kim Chuan

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DEDICATION

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ABSTRACT

Future wireless networks are envisioned to embrace a higher level of heterogeneity whereby different wireless technologies such as Long Term Evolution UMTS (LTE), Wireless Local Area Network (WLAN), WCDMA/HSPA, WiMAX, etc, not only will coexist but will also cooperate more closely. This is motivated by the fact that several complementary characteristics exist between these technologies. For example, one technology can be used as access technology while the other can be used for backhaul. To interconnect two or more wireless technologies, the usage of routing device is inevitable. In order to preserve the Quality of Service (QoS) across these technologies which come with different QoS definitions, a more comprehensive approach is required to preserve QoS across two diverse wireless technologies i.e. Enhanced Distributed Coordination Function (EDCA) for WLAN and Uplink/Downlink packet scheduling for LTE. WLAN is reasonably priced, easy to deploy and has been enjoying a wide market acceptance especially in the indoor. The LTE is expected to be the dominant 4G cellular technology. However it will take some time before LTE can attain the same level of adoption as what WLAN has achieved especially in the consumer market.

The main objective of this research project is to design an access router that enables the interworking between WLAN and LTE with QoS preservation. First, the performance of both WLAN and LTE radio interfaces are investigated independently in terms of the data rates, user/system throughput, effect of multiple access and spectral efficiency. Next, different approaches and schemes which facilitate QoS preservation between WLAN and LTE over the router are investigated and evaluated in terms of different performance metrics (voice Mean Opinion Score, video delay, video traffic received, video jitter, video packet loss rate). The design and analysis of the performance are carried out through simulation as the only feasible approach to accomplish this work. OPNET Modeler is used to model the LTE-WLAN router as well as to perform the analysis.

The results of this research verify the feasibility of the proposed router architecture and the interworking paradigm. The elegance of the proposed router implementation is that it does not require massive change in the existing wireless systems, LTE and WLAN to preserve the QoS. The results of the performance analysis show that it is crucial to have a QoS preservation mechanism in the router IP layer at any potential congestion point in the wireless network, to ensure that delay-sensitive and loss-sensitive applications, such as real-time video and voice, pass through unimpeded, relative to the loss-tolerant and delay-tolerant data applications. The comparison of the designed IP QoS preservation scheme namely, Priority Queuing without Block Acknowledgement (PQ noBA) shows that it can support 50% more multimedia application across the router than the other schemes.

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ABSTRAK

Masa hadapan rangkaian tanpa waya r 4G sedang dibangunkan dengan tujuan untuk mencapai kepelbagaian yang lebih tinggi dalam teknologi tanpa wa yar seperti Evolusi Jangka Masa Panjang UMTS (LTE), rangkaian ka wa san tempatan tanpa wayar (WLAN), WCDMA/HSPA, WiMAX, dan sebagainya. Hal ini disokong oleh fakta yang mengatakan beberape ciri pelengkap wujud antara teknologi-teknologi ini. Misalnya, sesebuah teknologi boleh digunakan sebagai teknologi akses sementara yang lain boleh digunakan untuk backhaul. Bagi menghubungkan dua atau lebih teknologi tanpa wayar, peranti laluan diperlukan antara kedua-dua platform yang berbeza ini. Dalam usaha untuk menekalkan kualiti perkhidmatan (QoS) antara teknologi yang berbeza dengan definasi tidak sama, pendekatan yang lebih menyuruh diperlukan untuk memelihara QoS. Denga n kata lain, EDCA untuk WLAN dan pautan naik / pautan turun penjadualan paket untuk LTE. WLAN masih pada harga yang munasabah, mudah untuk digunakan dan digunakan secara meluas terutamanya untuk kegunaan da laman. LTE dijangkakan mendominasi pasaran 4G selular teknologi. Walaubagaimana pun, ia akan mengambil masa sebelum teknologi LTE mencapai tahap sepertimana yang telah dicapai oleh WLAN dalam pasaran.

Objektif utama projek penyelidikan ini adalah untuk merekabentuk penghala capaian yang membolehkan jalinan kerja di antara WLAN dan LTE. Rekabentuk ini telah disahkan dan prestasi QoS penghala capaian telah pun dianalisis. Pertama, presta si WLAN dan juga LTE dikaji secara bera singan dari segi kadar da ta, pengguna/daya pemprosesan sistem, kesan akses pelbagai dan kecekapan spektrum. Seterusnya, pelbagai jenis pendekatan dan skema untuk memelihara QoS anta ra WLAN dan LTE melalui penghala telah pun dikaji dan dinilai dari pelbagai segi (min suara dan kelewatan, trafik yang diterima, ketaran, kadar hilang bingkisan video). Pemodelan rekabentuk dan analisis prestasi hanya dapat dijalankan melalui perisian 'OPNET Modeler'. Hasil daripada kajian ini mengesahka n kemungkinan untuk seni bina dan paradigma berkerjasama penghala yang dicadangkan. Kebaikan bagi penghala yang dicadangkan a dalah ia tidak memerlukan sebarang perubahan dalam sistem LTE dan WLAN ya ng sedia ada. Ha sil analisis presta si menunjukkan baha wa skema yang sesuai untuk pemeliharaan QoS adalah amat penting dalam lapisan IP apabila jumlah trafik yang masuk melebihi had lalu lintas. Pemetaan IP QoS memastikan baha wa peka kelewatan dan aplikasi peka kehilangan, seperti video masa nyata dan suara, dapat disalurkan tanpa halangan, berbanding dengan aplikasi tahan kehilangan data dan tahan kelewatan. Perbandingan antara skema pemuliharaan IP QoS yang telah direkabentuk, aturan keutamaan tanpa perakuan blok (PQ noBA) menunjukkan baha wa ia dapat menyokokong aplika si multimedia 50 peratus lebih da ripada skema pemuliharaan lain yang sedia ada.

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ACKNOWLEDGEMENTS

All praises are due to Almighty ALLAH for giving us the endurance and perseverance to complete this work. Peace and Blessings be upon the perfect of creations.

I would like to express my greatest gratitude to my supervisors, Dr. Lim Kim Chuan, Dr. David Chieng Heng Tze for their guidance, understanding, motivation and excellent support during this study and preparation of this thesis. I would like to express my gratitude to my ex-lecturer Dr. Lim Heng Siong for his incitation and the valuable information he provided in his classes and his great and continuous supports.

I emphasis my gratitude for my supervisor Dr. David Chieng Heng Tze for being a great manager for me during my work under his supervision in MIMOS Berhad who provided me with guidance and assistance that enabled me to work hard to finish this work successfully in a very difficult time.

I owe all achievements to them and am really thankful to my parents, brothers and sisters. I will never forget the huge support of my wife who was a great source to motivation and encouragement me every time to spend more time on my project. Last but not least, I would like to thank my friends, housemates, classmates and colleagues, for their friendship and precious help.

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ABSTRACT ... iiiiiiiii

ABSTRAK ... ii

ACKNOWLEDGEMENTS ... iii

TABLE OF CONTENTS ...iv

LIST OF TABLES ... vii

LIST OF FIGURES ... iviii LIST OF ABBREVIATIONS ... vivxi LIST OF PUBLICATIONS ... xv

CHAPTER PAGE 1. INTRODUCTION 1 1.1 Background ... 1

1.1.1 LTE - 4G wireless networks ... 1

1.1.2 Heterogeneous Wireless Networks ... 2

1.1.3 Router with QoS implementation ... 3

1.2 Problem Statement ... 4

1.3 Objectives ... 5

1.4 Scope of Works ... 6

1.5 Thesis Outline ... 6

2. LITERATURE REVIEW 7 2.1 LTE Overview ... 7

2.1.1 LTE radio access ... 8

2.1.2 Transmission scheme (OFDM)... 10

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2.1.2.2 Uplink SC-FDMA ... 11

2.2 WLAN overview (IEEE 802.11) ... 12

2.2.1 IEEE802.11n enhancements ... 13

2.2.1.1 PHY layer enhancements ... 13

2.2.1.2 MAC layer enhancements ... 15

2.2.2 Transmission scheme (CSMA/CA) ... 18

2.3 QoS in Wireless Communication ... 19

2.3.1 QoS in LTE ... 20

2.3.2 QoS in IEEE 802.11n ... 22

2.3.3 IP layer QoS... 24

2.4 Previous Work ... 25

2.4.1 Wireless router design ... 26

2.4.2 Cross technologies QoS preservation. ... 27

2.4.3 WLAN- LTE interworking ... 28

2.5 Summary ... 30

3. METHODOLOGY 31 3.1 Wireless Design in OPNET ... 32

3.1.1 LTE model in OPNET ... 33

3.1.2 WLAN model in OPNET ... 37

3.2 LTE-WLAN WR Design... 41

3.2.1 Proposed router architecture ... 41

3.2.2 Network protocol stack ... 43

3.2.3 Router processes functionalities ... 44

3.3 QoS Preservation Framework ... 48

3.4 Summary ... 51

4. WLAN AND LTE PERFORMANCE ANALYSIS 52 4.1 WLAN Performance Analysis ... 52

4.1.1 Simulation setup and general parameters ... 52

4.1.2 Effects of IP packet size ... 54

4.1.3 Effects of MCS ... 55

4.1.4 Effects of channel bandwidth ... 56

4.1.5 Effects of MIMO ... 57

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4.1.7 Effects of traffic type (ToS) ... 59

4.1.8 Efficiency loss due to multiple users ... 60

4.2 LTE Performance Analysis ... 61

4.2.1 Simulation configuration and parameters ... 61

4.2.2 Effects of channel bandwidth ... 63

4.2.3 Effects of TDD -FDD... 65

4.2.4 Effects of MCS index ... 66

4.2.5 GBR and non-GBR Bearers. ... 67

4.2.6 Effects of multiple users ... 70

4.3 Summary ... 71

5. WR PERFORMANCE ANALYSIS 72 5.1 Simulation Setup and Configurations ... 72

5.1.1 Voice and video applications (Applications details) ... 73

5.1.2 Parameters configuration ... 77

5.1.3 LTE and WLAN link capacities ... 79

5.2 WR Design Verification ... 81

5.2.1 Maximum data traffic ... 82

5.2.2 Introduced delay ... 83

5.2.3 LTE QoS in WR ... 84

5.2.4 WLAN QoS in WR ... 85

5.3 QoS Performance Analysis... 86

5.3.1 Voice MOS ... 88

5.3.2 Video traffic end-to-end delay ... 91

5.3.3 Video data delivery ... 93

5.3.4 Video packet loss rate ... 95

5.3.5 Video jitter ... 97

5.3.6 Summary ... 100

6. CONCLUSIONS 101 6.1 Conclusion ... 101

6.2 Recommendation and Future Work ... 103

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vii

LIST OF TABLES

TABLE TITLE PAGE

2.1 IEEE 802.11n MCS vs. PHY data rate 16

2.2 Standardized QCI for LTE 21

2.3 WLAN access categories (AC) 23

2.4 UP to AC mapping 24

4.1 WLAN default parameters 54

4.2 Summary of MIMO results 57

4.3 LTE default parmeters 62

4.4 No. of RB and bandwidth efficiency 64

4.5 MCS indexes and coding rates 66

5.1 Voice application details 74

5.2 Video application details 75

5.3 Parameter configurations 77

5.4 QCI-to-ToS mapping 87

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viii

LIST OF FIGURES

FIGURE TITLE PAGE

1.1 LTE-WLAN Interworking using the router 5

2.1 OFDMA transmission scheme 11

2.2 SC-FDMA transmission scheme 12

2.3 Channel bonding (AP_2) illustration 14

2.4 Illustration of frame aggregation techniques 17

2.5 EPS bearer architecture (TS 36.300) 22

2.6 Four access functions provided by 802.11e 23

2.7 3GPP WLAN- LTE interworking architecture 29

2.8 Protocol stack between WLAN UEPDG 30

3.1 OPNET modeler components 33

3.2 Data traffic flow in LTE networks. 34

3.3 LTE process models main tasks 36

3.4 LTE parameters in OPNET. 37

3.5 WLAN attributes in OPNET 39

3.6 WLAN configuration in infrastructure mode 40

3.7 WLAN Statistics collection in OPNET 41

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3.9 Network protocol stack- control plane 44

3.10 Network protocol stack - data plane 44

3.11 WR NAS process. 46

3.12 WR AS process 48

3.13 The Proposed QoS preservation framework 50

4.1 WLAN simulation setup. 53

4.2 Max link throughput vs. IP packet size 55

4.3 Maximum link throughput and TE vs. MCS(11g & 11n) 56 4.4 Effects of channel bonding on Max link throughput 57 4.5 Effects of MIMO spatial streams on Max link throughput 58

4.6 Aggregated AP throughput vs. No. of users 59

4.7 Aggregated AP Throughput vs. UP 60

4.8 TE vs. number of users 61

4.9 LTE simulation setup 63

4.10 Effects of channel bandwidth on throughput 65

4.11 Effects of FDD and TDD on throughput 66

4.12 Effects of MCS index on throughput (20 MHz, FDD) 67

4.13 GBR and non-GBR bearers (One UE) 69

4.14 GBR and non-GBR bearers (Multiple UEs) 69

4.15 Effects of multiple Users 71

5.1 Voice application trace 75

5.2 Video traffic trace 76

5.3 WR implementation scenario 78

5.4 Transmitted traffic 79

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5.6 WLAN link capacity 81

5.7 Maximum data rate 83

5.8 Introduced delay by WR 84

5.9 LTE functionalities on the WR 85

5.10 WLAN functionalities on the WR 86

5.11 Voice MOS BPSK1/2 89

5.12 Voice MOS QPSK1/2 90

5.13 Video delay BPSK1/2 92

5.14 Video delay QPSK1/2 93

5.15 Video received traffic BPSK1/2 94

5.16 Video received traffic QPSK1/2 95

5.17 Video loss rate BPSK1/2 96

5.18 Video loss rate QPSK1/2 97

5.19 Video jitter BPSK1/2 98

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LIST OF ABBREVIATIONS

ACRONYM DEFINITION

3GPP Third Generation Partnership Project

4G Fourth Generation Communication Networks

AAA Authentication, Authorization, Accounting

AC Access Categories

AIFS Arbitration Inter Frame Space

AMBR Aggregate Maximum Bit Rate

A-MPDU MAC Protocol Data Unit Aggregation

A-MSDU MAC Service Data Unit Aggregation

ARP Allocation and Retention Priority

AS Access Stratum

BA Blocked Acknowledgement

BC Backoff Counter

CSMA/CA Carrier Sense Multiple Access/Collision Avoidance

CW Contention Window

DCF Distributed Coordination Function

Diffserv Differentiated Service

DSSS Sequence Spreading Spectrum

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xii

EMM EPS Mobility Management

EPS Evolved Packed System

ESS Extended Service Set

FDD Frequency-Division Duplex

FHSS Frequency Hopping Spread Spectrum

GBR Guaranteed Bit Rate

GTP GPRS Tunneling Protocol

HARQ Hybrid Automatic Repeat-Request

HCCA HCF Controlled Channel Access

HCF Hybrid Coordination Function

HetNet Heterogeneous Networks

HT High Throughput

ICIC Inter-Cell Interference Coordination

IMS Internet Protocol Multimedia Subsystem

IMT-Advanced International Mobile Telecommunications-Advanced

ITU International Telecommunication Union

LTE Long Term Evolution

MAC Medium Access Control

MBMS Multimedia Broadcast Multicast Services

MBR Maximum Bit Rate

MCS Modulation And Coding Scheme

MIMO Multiple-Input Multiple-Output

NAS Non-Access Stratum

OFDM Orthogonal Frequency Division Multiplexing

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xiii

PAPR Peak-To-Average Power Ratio

PCF Point Coordination Function

PDCCH Physical Downlink Control Channel

PDCP Packet Data Convergence Protocol

PDG Packet Data Gateway

PDN Packet Data Network

PLCP Physical Layer Convergence Protocol

PLMN Public Land Mobile Network

PUCCH Physical Uplink Control Channel

QCI QoS Class Identifier

QoS Quality Of Service

RACH Random Access Channel

RB Resource Block

RE Resource Element

Rel. 8 Release 8

RIFS Inter-Frame Spacing

RLC Radio Link Control

RRC Radio Resource Control

RRM Radio Resource Management

RTP Real-Time Protocol

SC-FDMA Single Carrier- Frequency Division Multiple Access

SDM Spatial Division Multiplexing

SGI Short Guard Interval

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xiv

SIFS Single Inter-Frame Spacing

SISO Single Input Single Output

STA WLAN Station

STBC Space Time Block Coding

TDD Time-Division Duplex

TTI Transmit Time Interval

TxBF Transmit Beamforming

TXOP Transmission Opportunity

UE User Equipment

VOIP Voice Over IP

VoLTE Voice Over Long Term Evolution

WLAN Wireless Local Area Network

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LIST OF PUBLICATIONS

Journals:

[1] A M. Ghaleb, David Chieng, Alvin Ting, Ayad Abdulkafi, Kim-Chuan Lim, Heng-Siong Lim. "Modeling of QoS-Aware Hybrid LTE-WLAN Wireless Router," Smart Computing Review, 2013, (SCOPUS).

Conferences:

[1] A M. Ghaleb, David Chieng, Alvin Ting, Kae Hsiang Kwong, KC Lim, HS Lim. "Throughput Analysis of IEEE802.11n Using OPNET," The IET ICWCA2012, Kuala Lumpur, Malaysia, 2012.

[2] A M. Ghaleb, David Chieng, Alvin Ting, Ayad Abdulkafi, Kim-Chuan Lim, Heng-Siong Lim. "Preservation of QoS Across Hybrid LTE-WiFi Router," IET ICICT2013,Beijing, China, 2013.

[3] A M. Ghaleb, David Chieng, Alvin Ting, Kae Hsiang Kwong, KC Lim, HS Lim. "Throughput Performance Insights of LTE Release 8: Malaysia's Perspective," IWCMC2013-Wireless Nets, Italy, 2013.

Other works (not directly related to the thesis but in the field Heterogeneous Networks):

Journals:

[1] Abdulkafi, A.A, Tiong Sieh Kiong, Chieng D., Ting, A M. Ghaleb, Johnny Koh. "Modeling of Energy Efficiency in Heterogeneous Network," Research Journal of Applied Sciences, Engineering and Technology, 2013, (ISI)

Conferences:

[1] Abdulkafi, A.A., Tiong Sieh Kiong, Koh, J., Chieng, D., Ting, A., Ghaleb, A.M. "Energy Efficiency of LTE Macro Base Station," ISTT2012, Kuala Lumpur, Malaysia, 2012.

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CHAPTER 1

1. INTRODUCTION

Wireless communication technology has turned out to be one of the most important aspects of today’s society. Nowadays the number of cellular wireless services subscribers has exceeded the number of the wired telephone services subscribers. Beside cellular wireless technology, other wireless technologies are being extensively used for voice as well as for data communication applications and entertainment services such as Wireless Local Area Networks (WLANs), cordless phones, radars and satellites. During the last two decades considerable numbers of researches have been dedicated for the development of wireless communication technology. Indeed, recently, it has emerged as the most thriving branch of development in the area of telecommunication (Hossain et al., 2009).

1.1 Background

This Section provides quick overview of the 4G wireless communication in general (Section 1.1.1), overview of the heterogeneous wireless networks (Section 1.1.2) and discuss the importance of having the router model in wireless heterogeneous networks and the QoS preservation scheme across the router (Section 1.1.3) .

1.1.1 LTE - 4G wireless networks

The fourth generation of wireless communication networks, which is known as 4G, will fuel the future wireless landscape with greater innovations. The ultimate aim for 4G

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networks is to overcome the limitation of the current wireless network by the provisio n of a comprehensive and secure IP-based solution with much faster data transmission speeds. There is a standard definition as specifications of 4G by International Mobile Telecommunications-Advanced (IMT-Advance). 4G networks are designed to provide a higher quality of service, better reception, less packet loss/drop, improved all-IP multimedia services and interactive roaming between networks in order to fulfill the requirements of the IMT-Advanced issued by International Telecommunication Union (ITU) (Dahlman et al., 2011, Govil, 2008, Khan et al., 2009, Qing et al., 2008). Long- Term Evolution UMTS (LTE) is promising technology to meet the requirements of 4G wireless networks.

1.1.2 Heterogeneous Wireless Networks

The words Heterogeneous Network, referred to as HetNet, describe a network that consist of different access technologies, network that contain nodes operating with different parameters such as power, frequency, etc. Nowadays the demand for data traffic in cellular and other wireless networks is growing exponentially. Improving system spectral efficiency can only be achieved by increasing the number of the deployed nodes in the network since the link efficiency approaches its theoretical limits. However, increasing the number of nodes in dense deployment of macro base stations is not a choice since the sever introduced inter-cell interference significantly decreases the cell splitting gains. To solve the problem, low-power nodes such as pico, femto and relay nodes can be integrated into the network and forming a heterogeneous network containing macrocells and mix of low-power nodes from the same access technology (Damnjanovic et al., 2011). Interworking of different wireless networks under the umbrella of the heterogeneous network is of prime importance, more specifically WLAN and cellular integration (Ferrus

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et al., 2010). However, developing solutions and designing architecture for the interworking are still open research.

1.1.3 Router with QoS implementation

WLANs achieve a great penetration in the market as an efficient solution for providing Internet mobile access; around the world, millions of WLANs connections, so-called hot spots, are deployed in particular locations, such as hotels, restaurants or airports. HetNets based on different access technologies, where macro network is based on a cellular technology and low power access points are based on WLANs are targeted in order to reduce the operating cost and double the resources hence, provide wireless access at a reasonable price and with a satisfactory data rates (Damnjanovic et al., 2011). Wireless router has to be implemented properly in order to enable interworking of the two different wireless technologies (WLAN and LTE) to work together in a complementary manner in forming the heterogeneous wireless networks.

Many challenges to the interworking arise when employing 3G/4G cellular networks and WLANs (El-Sayed et al., 2008). WLANs and LTE present different characteristics in terms of mobility management, security support, and end-to-end Quality of Service (QoS) provisioning. These issues should be carefully handled while developing the interworking schemes of the WLANs and LTE in order to achieve seamless integration.

With the increase of bandwidth promised by the WLANs and LTE network, more IP based multimedia applications, e.g. Voice over IP and video conferencing, running simultaneously over the router is to be expected. Running the application in real time, the media content need not be downloaded in full, but is being played out while parts of the content are being received and decoded. Due to its real-time nature, supporting video and audio streaming typically requires the router to guarantee the bandwidth and delay that

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maintain the streaming quality. If the data does not arrive in time, the play out process will pause, which is annoying to end users. QoS guaranteed by the router is important when the network capacity is not enough to support both the real-time multimedia streams and non-delay-sensitive applications (e. g. web browsing). On the other hand, wireless network hardly guarantee the QoS due to the changing environment of the wireless medium which affect the capacity of the network (Namee, 2009).

1.2 Problem Statement

4G wireless networks are envisioned to embrace a higher level of heterogeneity whereby different wireless technologies such as LTE, WLAN, WCDMA/HSPA, WiMAX, etc, not only will coexist but will also cooperate more closely. This is motivated by the fact that several complementary characteristics exist between these technologies. The protocols and interworking architectures between different wireless access technologies are still emerging areas of research.

To interconnect two or more wireless technologies, the usage of routing device is inevitable. Unfortunately, there is no complete LTE-WLAN internetworking architectures platform and no visible wireless router design in the research arena. In order to preserve the QoS across these technologies which come with different QoS definitions, a more comprehensive approach is required to preserve QoS across two diverse wireless technologies i.e. Enhanced Distributed Channel Access (EDCA) for WLAN and Uplink/Downlink packet scheduling for LTE. However, QoS preservation across LTE-WLAN interface (router) is not addressed yet. Figure ‎1.1 show an interworking scheme between LTE network and WLAN where the former is used as backhaul and the later as access technology. To effectively interwork these technologies, both technologies should be analyzed in terms of the data rates, user/system throughput and spectral efficiency. The

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xiv

SIFS Single Inter-Frame Spacing

SISO Single Input Single Output

STA WLAN Station

STBC Space Time Block Coding

TDD Time-Division Duplex

TTI Transmit Time Interval

TxBF Transmit Beamforming

TXOP Transmission Opportunity

UE User Equipment

VOIP Voice Over IP

VoLTE Voice Over Long Term Evolution

WLAN Wireless Local Area Network

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LIST OF PUBLICATIONS

Journals:

[1] A M. Ghaleb, David Chieng, Alvin Ting, Ayad Abdulkafi, Kim-Chuan Lim, Heng-Siong Lim. "Modeling of QoS-Aware Hybrid LTE-WLAN Wireless Router," Smart Computing Review, 2013, (SCOPUS).

Conferences:

[1] A M. Ghaleb, David Chieng, Alvin Ting, Kae Hsiang Kwong, KC Lim, HS Lim. "Throughput Analysis of IEEE802.11n Using OPNET," The IET ICWCA2012, Kuala Lumpur, Malaysia, 2012.

[2] A M. Ghaleb, David Chieng, Alvin Ting, Ayad Abdulkafi, Kim-Chuan Lim, Heng-Siong Lim. "Preservation of QoS Across Hybrid LTE-WiFi Router," IET ICICT2013,Beijing, China, 2013.

[3] A M. Ghaleb, David Chieng, Alvin Ting, Kae Hsiang Kwong, KC Lim, HS Lim. "Throughput Performance Insights of LTE Release 8: Malaysia's Perspective," IWCMC2013-Wireless Nets, Italy, 2013.

Other works (not directly related to the thesis but in the field Heterogeneous Networks):

Journals:

Conferences:

[1] Abdulkafi, A.A., Tiong Sieh Kiong, Koh, J., Chieng, D., Ting, A., Ghaleb, A.M. "Energy Efficiency of LTE Macro Base Station," ISTT2012, Kuala Lumpur, Malaysia, 2012.

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CHAPTER 1

1. INTRODUCTION

1.1 Background

1.1.1 LTE - 4G wireless networks

The fourth generation of wireless communication networks, which is known as 4G, will fuel the future wireless landscape with greater innovations. The ultimate aim for 4G

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1.1.2 Heterogeneous Wireless Networks

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et al., 2010). However, developing solutions and designing architecture for the interworking are still open research.

1.1.3 Router with QoS implementation

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Design and analysis of LTE-WLAN wireless router with QOS preservation.

Faculty of Electronic and Computer Engineering