Radio Resource Management Strategies in LTE Networks

Ricardo Jorge Teixeira Carona de Sousa

Thesis to obtain the Master of Science Degree in

Electrical and Computer Engineering

Supervisor: Prof. Antnio Jos Castelo Branco Rodrigues

Examination Committee

Chairperson: Prof. Jos Eduardo Charters Ribeiro da Cunha SanguinoSupervisor: Prof. Antnio Jos Castelo Branco Rodrigues

Members of the Committee: Prof. Francisco Antnio Bucho CercasEng. Diana Paula dos Santos Ladeira

May 2016

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To my loved ones.

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Acknowledgments

First and foremost, I would like to thank my parents, Helena and Jorge, for everything theyve done for

me throughout my whole life. All the help, support and love, that has allowed me to get to where I am

today.

A great acknowledgement to my thesis supervisor Professor Antonio Rodrigues, for the opportunity

given to me with the possibility to tackle this challenge, and the support during it.

To my company, Altran, for the opportunity given, and namely Diana Ladeira and Joao Lopes, for all

the support and readiness to help with anything I needed, pushing me to better myself every time and

accompanying me through this whole journey. Also, a thank you to my remaining colleagues for the

company and everyday life that we shared for several months.

Also, a thank you to the telecommunications operator, whose data supplied was of immense value for

this thesis.

To all my friends, for the good times that kept me going through the hard parts and just being there for

me.

Last, but not least, my biggest thanks go to my girlfriend Beatriz Loura, for being with me every step of

the way, always with a tremendous amount of affection. Her love and support contribute every day to

make me a better person, in every way.

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Resumo

Com a massificacao de redes Long Term Evolution (LTE) e o seu crescente uso entre os utilizadores de

redes moveis, a necessidade de gerir eficientemente os recursos radio torna-se cada vez mais essen-

cial, de forma a manter os nveis de Quality of Service (QoS) sem afectar a viabilidade economica. Esta

dissertacao propoe um novo algoritmo de controlo de admissao. A combinacao de metodos tais como

handovers forcados, lista de espera e degradacao de servico permite uma perspectiva customizavel

no que diz respeito ao controlo de admissao, aplicando limites rgidos de QoS e uma alta capacidade

em termos de numero de utilizadores activos simultaneamente. Para avaliar e obter resultados validos

acerca do seu desempenho, o simulador LTE System Level Downlink Simulator foi adaptado e usado,

em varios cenarios de mundo real, baseados em dados obtidos de um operador inserido no mercado

de telecomunicacoes Portugues. Os cenarios analisados incluram variacoes nas taxas de penetracao

de servicos, banda de frequencia usada, e disposicao da rede - urbana ou suburbana. Os resulta-

dos mostram melhorias no que diz respeito a capacidade, com a contrapartida de os Key Performance

Indexes (KPIs) serem ligeiramente afectados, nomeadamente as taxas de transferencia, os atrasos, o

jitter e o signal-to-interference-plus-noise ratio (SINR). O aumento de capacidade, para o alvo de 5% de

probabilidade de bloqueio, e de 57% e 73% para os cenarios suburbanos e urbanos, respectivamente.

Palavras-chave: Gestao de Recursos Radio, LTE, Controlo de Admissao, LTE System LevelDownlink Simulator, Equilbrio de Carga, Qualidade de Servico

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Abstract

With the massification of Long Term Evolution (LTE) networks and their growing usage among all mobile

users, the necessity to efficiently manage the available radio resources becomes more and more essen-

tial, in order to maintain Quality of Service (QoS) levels while sustaining economic viability. This thesis

proposes a newly developed priority based call admission control algorithm. The combination of meth-

ods such as forced handovers, queue list and service degradation allows for a customizable approach

to admission control, between rigid QoS limits and high capacity in the number of simultaneously active

users. To assess and obtain valid results about its performance, one adapted and used the LTE System

Level Downlink Simulator, in various real world scenarios, based in data obtained from an operator in the

Portuguese telecommunications sector. Analysed scenarios included variations in the services penetra-

tion rates, frequency band, available bandwidth and network layout - urban and suburban. Results show

improvements regarding the increase in capacity, with the trade-off of slightly hindering Key Performance

Indexes (KPIs) such as throughput, delay, jitter and signal-to-interference-plus-noise ratio (SINR). The

increase in capacity, for the same target blocking probability of approximately 5% is of 57% and 73% for

Suburban and Urban scenarios, respectively.

Keywords: Radio Resource Management, LTE, Admission Control, LTE System Level DownlinkSimulator, Load Balancing, Quality of Service

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Contents

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Resumo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix

List of Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii

1 Introduction 1

1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Thesis Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Fundamental Concepts 5

2.1 Mobile Telecommunication Systems Evolution . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1.1 Network Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 LTE - Long Term Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.2.1 Core Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2.2 Access Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.2.3 Radio Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.2.4 LTE-A Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.2.5 Services and Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.2.6 Coexistence with other systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.3 Radio Resource Management in LTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.3.1 Admission Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.3.2 Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3 Algorithm Development and Simulation Environment 25

3.1 Simulator Aspects, Limitations and Adaptations . . . . . . . . . . . . . . . . . . . . . . . . 25

3.1.1 Traffic Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.2 Implemented Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.2.1 Algorithm Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.2.2 Load Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

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3.2.3 Call Admission Control Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3.2.4 Queue List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3.2.5 Quality of Service verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

3.3 Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

3.3.1 Input parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

3.3.2 Produced Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

3.4 Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

3.4.1 Simulations Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3.4.2 Starting number of User Equipments . . . . . . . . . . . . . . . . . . . . . . . . . . 41

3.4.3 Final Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4 Results Analysis and Comparison 43

4.1 Active User Equipments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.2 Urban 800 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4.2.1 Reference vs +VoIP vs +Gaming . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4.2.2 Reference vs Bandwidth Variation . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

4.3 Suburban 800 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

4.3.1 Reference vs +VoIP vs +Gaming . . . . . . . . . . . . . .