radio resource manaagement in umts

TEAM LinG RADIO RESOURCE MANAGEMENT STRATEGIES IN UMTS RADIO RESOURCE MANAGEMENT STRATEGIES IN UMTS Jordi Pe ´ rez-Romero Oriol Sallent Ramon Agustı ´ All of Universitat Polite ` cnica de Catalunya (UPC), Spain Miguel Angel Dı ´ az-Guerra Telefo ´ nica Mo ´ viles Espan ˜ a, S.A., Spain Copyright ß 2005 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England Telephone (þ44) 1243 779777 Email (for orders and customer service enquiries): cs-books@wiley.co.uk Visit our Home Page on www.wiley.com All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the permission in writing of the Publisher. 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Contents Preface ix List of Acronyms xi 1 Introduction 1 1.1 The mobile communications sector 1 1.1.1 The mobile experience 2 1.1.2 The business case 2 1.1.3 A learning case study: Japan 4 1.1.4 Regional perspectives in mobile evolution towards 4G 5 1.1.5 Technology developments 6 1.2 UMTS 7 1.2.1 UMTS architecture 7 1.2.2 UMTS evolution 13 1.3 QoS model in UMTS 15 References 17 2 CDMA Concepts 19 2.1 Multiple access techniques 19 2.2 CDMA signal generation 21 2.3 CDMA signal reception 25 2.3.1 Single user case 26 2.3.2 Presence of narrowband interference 27 2.3.3 Multiple user case 29 2.3.4 Effect of the mobile radio channel 37 2.4 CDMA in cellular systems 41 2.4.1 Intercell interference 41 2.4.2 Soft handover 43 References 44 3 UMTS Radio Interface Description 47 3.1 The UMTS protocols 47 3.2 Radio interface protocol structure 50 3.2.1 Logical channels 52 3.2.2 Transport channels 52 3.2.3 Physical channels 56 3.2.4 Mapping between logical, transport and physical channels 59 3.3 Physical layer 61 3.3.1 Processing of transport blocks 62 3.3.2 Spreading and modulation 68 3.3.3 Downlink transmit diversity schemes 71 3.3.4 Organisation of the physical channels 73 3.4 Layer 2 protocols 96 3.4.1 Medium Access Control (MAC) protocol 96 3.4.2 Radio Link Control (RLC) protocol 98 3.4.3 Packet Data Convergence Protocol (PDCP) 101 3.4.4 Broadcast/Multicast Control (BMC) protocol 102 3.5 Radio Resource Control (RRC) protocol 102 3.5.1 Architecture 103 3.5.2 RRC states 104 3.5.3 RRC functions and procedures 106 3.6 Examples of Radio Access Bearers 112 3.6.1 Signalling Radio Bearer 3.4 kb/s through DCH 113 3.6.2 RAB for a 64/384 kb/s interactive service and 3.4 kb/s signalling 115 References 118 4 Basics of RRM in WCDMA 119 4.1 Radio Resource concept 119 4.2 Radio network planning 120 4.3 Radio Resource Management 121 4.4 Air interface characterisation 125 4.4.1 Camping, active and simultaneous users 125 4.4.2 Uplink: Single cell case 128 4.4.3 Uplink: Multiple cell case 131 4.4.4 Downlink: Single cell case 136 4.4.5 Downlink: Multiple cell case 141 4.5 RRM functions 144 4.5.1 Admission control 145 4.5.2 Congestion control 147 4.5.3 Code management 148 4.5.4 Handover 150 4.5.5 UE-MAC and packet scheduling 151 4.5.6 Power control 153 4.5.7 Interactions among RRM functions 153 4.6 System characteristics relevant at RRM level 156 4.6.1 Service and user heterogeneity 157 4.6.2 Spatial traffic distribution heterogeneity 159 4.6.3 Indoor traffic 169 References 173 Appendix - Path loss distribution 173 5 RRM Algorithms 177 5.1 RRM algorithm evaluation methodology 177 5.1.1 UMTS radio network planning procedure 178 5.1.2 RRM algorithm evaluation by means of simulations 191 vi Contents 5.2 Admission control algorithms 198 5.2.1 Uplink case 199 5.2.2 Downlink case 218 5.3 Handover and cell selection algorithms 237 5.3.1 Requirements for GSM-UMTS interoperation 238 5.3.2 PLMN, RAT and cell selection algorithms 239 5.3.3 Handover algorithms 246 5.3.4 Neighbour cell list definition 257 5.4 Congestion control algorithms 258 5.4.1 General steps of a congestion control algorithm 261 5.4.2 Congestion resolution strategies 264 5.4.3 Congestion recovery algorithms 268 5.4.4 Setting of congestion control parameters 269 5.4.5 Multi-cell congestion control algorithm 271 5.5 Short term RRM algorithms 274 5.5.1 Uplink UE-MAC algorithms 274 5.5.2 Packet scheduling algorithms in the downlink 281 5.6 Power control 288 References 290 Appendix - Simulation models 293 A5.1 Propagation models 293 A5.1.1 Macrocell propagation 293 A5.1.2 Microcell propagation 294 A5.2 Mobility models 296 A5.2.1 Mobility model for macrocell environments 296 A5.2.2 Mobility model for microcell environments 297 A5.3 Traffic models 297 A5.3.1 Video-telephony traffic model 298 A5.3.2 Video-streaming traffic model 298 A5.3.3 WWW browsing traffic model 300 A5.3.4 Email traffic model 300 6 CRRM in Beyond 3G Systems 303 6.1 Heterogeneous networks 303 6.2 Radio Access Networks characterisation 305 6.2.1 GERAN 305 6.2.2 WLAN 309 6.3 Interworking and coupling among Radio Access Networks 313 6.3.1 UTRAN/GERAN interworking 313 6.3.2 UTRAN/WLAN interworking 318 6.4 Flexible radio resource and spectrum management 323 6.5 CRRM algorithm implementation 325 6.5.1 Interactions between CRRM and local RRM 325 6.5.2 RAT selection schemes 329 References 335 Index 337 Contents vii Preface It is more than a decade since GSM was first commercially available. After some unexpected delay, it seems that finally UMTS is here to stay as a 3G system standardised by 3GPP, at least for another ten years. UMTS will enable multi-service, multi-rate and flexible IP native-based mobile technologies to be used in wide area scenarios and also pave the way for a smooth transition from circuit switched voice networks to mobile packet services. The scarcity of available spectrum, particularly as seen in the auctions and beauty contests that preceded the final licences allocation for UMTS operators, has revealed, to a larger extent than in the past, the importance of using the spectrum efficiently. Radio access systems such as UTRAN in UMTS certainly exploit higher system spectrum efficiencies than 1G and 2G by using advanced coding, multiple access, diversity schemes, etc. On the other hand, the WCDMA technique adopted in UTRAN makes the accurate control of the inherent interference generated by this access a key issue in the good behaviour of the system. In addition, the inherent flexibility and high user bit rates provided by UMTS makes this interference control even more difficult. Therefore, manufacturers have to introduce, on a proprietary basis, much more involved Radio Resource Management (RRM) strategies than those used in the past, so that an efficient use of the available spectrum can be achieved. A complete picture of these RRM techniques has to include the retention of the QoS per service at the agreed values as an ultimate trade-off. Certainly, handling interference in UMTS will take the place of frequency planning in 1G and 2G systems to a much greater extent and will be one of the most important tasks if operators are to run the system efficiently. This self-contained book, consisting of six chapters, intends to bring to the reader, in a comprehensive and systematic way, the material needed to understand the interiorities of the RRM strategies in the context of UMTS. This book is addressed to undergraduate students, engineers and researchers who would like to explore the UMTS world and learn how to run and improve its radio access part in an operative scenario. Although a short radio planning basis is provided, RRM concepts are actually exploited in different scenarios that go beyond the planning pre-operational stages so that eventually the radio resources can be efficiently exploited in a near real time operation. The organisation of the book is represented schematically overleaf. In particular, Chapter 1 provides the introduction to the mobile communications sector and to UMTS, including the evolution towards the 4G systems. Also, it provides an overview of the QoS concept, which is key for the definition of Radio Resource Management strategies. After this introduction, the book is split into two different paths. The first path, which includes Chapters 2 and 4, is intended to provide the required theoretical fundamentals while the second, including Chapters 3, 5 and 6, presents to the reader how these theoretical aspects are translated into practical algorithms and systems. In that sense, Chapters 2 and 3 cover the characterisa- tion of the radio access in UMTS. Specifically, Chapter 2 provides a brief description of the CDMA technique that constitutes the basis for the UMTS radio access network. In turn, Chapter 3 presents the [...]... 1.2.1.2 Infrastructure Domain The infrastructure domain in the UMTS architecture contains the physical nodes that terminate the radio interface allowing the provision of the end-to-end service to the UE In order to separate the UMTS 9 functionalities that are dependent on the radio access technology being used from those that are independent, the infrastructure domain is in turn split into two domains,... for Comments Routing Function Entity Received Level Average Radio Link Control Rate Matching Radio Network Controller Radio Network Subsystem Radio Network Subsystem Application Part Radio Network Temporary Identity Robust Header Compression Radio Resource Radio Resource Control Radio Resource Equivalent Unit Radio Resource Management Radio Resource Unit List of Acronyms xvi RSCP RSSI RT RTP SACCH SAP... in the initial release of UMTS consist of a new radio access network based on a different radio access technology, while keeping the core network similar to that existing in GSM/GPRS systems After this initial implementation, the subsequent releases of the UMTS system introduce important changes in the architecture of the core network, taking the Internet Protocol (IP) as the driving technology In the... established Both domains are separated by means of the Uu reference point, which represents the radio interface, and their elements are explained in the following sub-sections 1.2.1.1 User Equipment Domain The User Equipment domain consists of the terminal that allows the user access to the mobile services through the radio interface From an architectural point of view, it is split into two sub-domains, separated... subscribers in Japan, of which 84% were using some kind of Internet browsing service In 2003, the average annual revenue per i-mode user was about 200 s, most of which stems from packet transmission charges The primary use of mobile Internet in Japan is for email: over 83% of mobile subscribers use the mobile Internet for sending and receiving email Downloading or listening to online music, such as ring tones... PCCH List of Acronyms Institute of Electrical and Electronics Engineers Internet Engineering Task Force IP Multimedia Subsystem International Mobile Subscriber Identity International Mobile Telecommunications 2000 Internet Protocol Institute for Prospective Technological Studies Inter Radio Network Subsystem Application Part Interim Standard 95 Integrated Service Data Network International Organisation... any UMTS network, with independency of the specific release [7] It is organised in domains, and each domain represents the highest level group of physical entities Reference points are defined between the different domains The basic split considers the User Equipment (UE) domain, used by the user to access the UMTS services, and the Infrastructure domain, Introduction 8 User Equipment (UE) domain Infrastructure... mobile Internet users in the world NTT DoCoMo launched its Internet connection service, ‘i-mode’, in February 1999 i-mode subscribers can connect to the Internet through special designated handsets The main services are email, information services and applications such as Internet banking and ticket reservation Other mobile operators in Japan also began competitive Internet connection services in 1999 In. .. compatible with UMTS, promoting its enhancement and ensuring the removal of any barriers to its adoption It should include provisions for spectrum regulation harmonisation and interconnection issues, which would allow investments in 3G infrastructure to be recouped without missing the opportunities stemming from technological innovation in other areas The US appears to lack a shared industry-wide view... Infrastructure domain Home Network (HN) domain [Zu] UMTS Subscriber Identity Module (USIM) domain Cu Mobile Equipment (ME) domain Uu Access Network (AN) domain Iu Serving Network (SN) domain [Yu] Transit Network (TN) domain Core Network (CN) domain Figure 1.1 General UMTS architecture composed of the physical nodes, belonging to the network operator, that support the service requirements and the interconnection . Part RNTI Radio Network Temporary Identity ROHC Robust Header Compression RR Radio Resource RRC Radio Resource Control RREU Radio Resource Equivalent Unit RRM Radio Resource Management RRU Radio Resource. 305 6.2.2 WLAN 309 6.3 Interworking and coupling among Radio Access Networks 313 6.3.1 UTRAN/GERAN interworking 313 6.3.2 UTRAN/WLAN interworking 318 6.4 Flexible radio resource and spectrum management. TEAM LinG RADIO RESOURCE MANAGEMENT STRATEGIES IN UMTS RADIO RESOURCE MANAGEMENT STRATEGIES IN UMTS Jordi Pe ´ rez-Romero Oriol Sallent Ramon Agustı ´ All