UMTS Network Planning, Optimization, and Inter-Operation with GSM - Rilegato

Rahnema, Moe

Rilegato

ISBN 10: 0470823011 ISBN 13: 9780470823019

Casa editrice: IEEE, 2008

Riassunto

UMTS Network Planning, Optimization, and Inter-Operation with GSM is an accessible, one-stop reference to help engineers effectively reduce the time and costs involved in UMTS deployment and optimization. Rahnema includes detailed coverage from both a theoretical and practical perspective on the planning and optimization aspects of UMTS, and a number of other new techniques to help operators get the most out of their networks.

• Provides an end-to-end perspective, from network design to optimization
• Incorporates the hands-on experiences of numerous researchers
• Single authorship allows for strong coherency and accessibility
• Details the complete iteration cycle of radio link budgeting for coverage planning and dimensioning

Rahnema demonstrates detailed formulation of radio capacity and coverage in UMTS, and discusses the tradeoffs involved. He presents complete link budgeting and iterative simulations for capacity and coverage planning, along with practical guidelines. UMTS Network Planning contains seventeen cohesive and well-organized chapters which cover numerous topics, including:

• Radio channel structures, radio channel models, parameters, model tuning
• Techniques for capacity and coverage enhancements
• Complete treatment of power control, handoffs and radio resource practical management processes and parameters
• Detailed coverage of TCP protocol enhancement for operation over wireless links, particularly UMTS
• Application of GSM measurements to plan and re-engineer for UMTS radio sites
• Guidelines for site co-location with GSM, the QOS classes, parameters and inter-workings in UMTS
• AMR voice codecs and tradeoffs, core and access network design, architectural evolution, and protocols
• Comprehensive discussion and presentation of practical techniques for radio performance analysis, trending, and troubleshooting

Perfect for professionals in the field and researchers specializing in network enhancement. Engineers working on other air interfaces and next generation technologies will find many of the techniques introduced helpful in designing and deploying future wireless networks as well. Students and professionals new to the wireless field will also find this book to be a good foundation in network planning, performance analysis, and optimization.

Su questo libro

Informazioni sull?autore

Moe Rahnema is a consultant providing advisory services to major network equipment vendors and mobile operators in the areas of network planning, network architecture and solution development, as well as radio coverage planning and optimization of 3G/UMTS, GSM, and GPRS. His clients have included Ericsson, Nokia, America Movile (Mexico), T-Mobile (USA), Excelcomindo (Indonesia), Maxis (Malaysia), LCC International (US & UK), and General Telephone and Electronics (USA). He has also held Principal Engineer positions at Hughes Network Systems (US) and Motorola Satellite Communications (US). Rahnema has published in IEEE magazines and journals, as well as with commercial technical magazines on wireless communications. He also has 8 US patents in the wireless communications field. Rahnema holds an M.S. and has completed coursework equivalent to two PhDs in Electrical Engineering and Aeronautics and Astronautics, from Northeastern University and MIT, respectively.

• Provides an end-to-end perspective, from network design to optimization
• Incorporates the hands-on experiences of numerous researchers
• Single authorship allows for strong coherency and accessibility
• Details the complete iteration cycle of radio link budgeting for coverage planning and dimensioning

Rahnema demonstrates detailed formulation of radio capacity and coverage in UMTS, and discusses the tradeoffs involved. He presents complete link budgeting and iterative simulations for capacity and coverage planning, along with practical guidelines. UMTS Network Planning contains seventeen cohesive and well-organized chapters which cover numerous topics, including:

• Radio channel structures, radio channel models, parameters, model tuning
• Techniques for capacity and coverage enhancements
• Complete treatment of power control, handoffs and radio resource practical management processes and parameters
• Detailed coverage of TCP protocol enhancement for operation over wireless links, particularly UMTS
• Application of GSM measurements to plan and re-engineer for UMTS radio sites
• Guidelines for site co-location with GSM, the QOS classes, parameters and inter-workings in UMTS
• AMR voice codecs and tradeoffs, core and access network design, architectural evolution, and protocols
• Comprehensive discussion and presentation of practical techniques for radio performance analysis, trending, and troubleshooting

Perfect for professionals in the field and researchers specializing in network enhancement. Engineers working on other air interfaces and next generation technologies will find many of the techniques introduced helpful in designing and deploying future wireless networks as well. Students and professionals new to the wireless field will also find this book to be a good foundation in network planning, performance analysis, and optimization.

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UMTS Network Planning, Optimization, and Inter-Operation with GSM

By Moe Rahnema

John Wiley & Sons

Copyright © 2008 John Wiley & Sons, (Asia) Pte Ltd
All right reserved.
ISBN: 978-0-470-82301-9

Chapter One

Introduction

The information revolution has created a new `post-industrial paradigm', which has transformed the way we live and work, the way we create arts, and the way we make new products and provide services. Clearly information technology has completely changed from a network of oral and print mechanisms to one that is electronic, visual, and multimedia. Along with this development has come the natural evolution of the speed with which information is transferred, from months and days to nanoseconds. This was made possible with the merging of the computer and the telephone, which prompted the emergence of a communications revolution. And it is needless to say that the wireless technologies have played and will continue to play the crucial role in this revolution, as they are the most convenient, efficient, and personal means of communicating information.

The tremendous growth in wireless communication technology over the past decade, along with reduced costs, has created major changes in people's communication habits, social and business networking, and lifestyles. This has in turn led to an explosive growth in the number of subscribers and the traffic placed on wireless networks. It is notable that the growth in voice traffic alone, which is currently the main source of revenues for most operators, is in many cases placing a huge burden on the existing capacity limited second generation (2G) systems such as GSM and other TDMA networks. On the other hand new bandwidth consuming applications, such as access to information on the move, video messaging, music downloading, mobile location based content retrieval, and voice calls with simultaneous access to data or images, are or will soon place new demands on capacity. The best answer to this explosive demand in capacity on the move is the provision of new spectrums and the deployment of advanced spectrally efficient multiple access techniques that can efficiently offer multiple type services from a wide range of bit rate characteristics and quality requirements on demand over the radio link. The Wideband CDMA (W-CDMA) technology is currently one such efficient and flexible radio access technology adopted for the implementation of the third generation (3G) wireless networks.

1.1 Overview of 3G Standards and WCDMA Releases

UMTS (Universal Mobile Telecommunication System) is the European 3G Standard based on W-CDMA technology, and is normally the solution generally preferred by countries that used GSM for the 2G network. UMTS is managed by the 3GPP organization, which also became responsible for the GSM continued standardization from July 2000. CDMA2000 is another significant 3G standard that is an outgrowth of the earlier 2G CDMA standard IS-95. CDMA2000's primary proponents are mainly in the Americas, Japan, and Korea, though UMTS is being tested and deployed at this time in the Americas by T-Mobile and Cingular. CDMA2000 is managed by 3GPP2, which is separate and independent from UMTS's 3GPP. The various types of transmission technology used in CDMA2000 include 1xRTT, CDMA2000-1xEV-DO, and 1xEV-DV. China has also come up with a Standard of its own, referred to as TD-SCDMA, which has been developed by the companies Datang and Siemens, for which field trails have been taking place in Beijing and Shanghai.

The first commercial UMTS network was deployed by Japan's NTT DoCoMo in 2001. Since then UMTS networks have been deployed in more than 20 countries including Germany, France, UK, Malaysia, Netherlands, Norway, Singapore, Spain, and Bahrain. The 3G networks based on WCDMA continue to be deployed in more and more countries. This situation is demanding that more and more radio planning professionals become more familiar with the WCDMA technology to design and launch high quality 3G networks. This book has been written with a heavy emphasis on radio planning and optimization principles for RF engineering professionals. The book also contains four extensive chapters (Chapters 13 to 16), which discuss the end-to-end QoS (Quality of Service) inter-working, and the design, dimensioning, and optimization of the access network, the core network, and the Transmission Control Protocol (TCP) protocol for wireless networks. Therefore this book is expected to benefit protocol and core network engineering professionals as well, and provide a good reference for the end-to-end network planning and optimization. 3G network planning involves a number of new challenges over the 2G networks, which relate to the underlying WCDMA radio access, the multi-service requirements, and opportunities to make use of new technologies in the core network such as the split connection and call control architectures (soft switching) for the design of efficient scaleable and flexible network architectures. These challenges are briefly outlined in this introductory chapter, and then discussed in greater detail and depth in the remaining chapters. This book is also expected to be highly valuable for graduate level students and new researchers in the field with an interest in the WCDMA technologies for network planning and optimization.

The development of the UMTS specifications based on W-CDMA in 3GPP has taken several phases. The first release of the UMTS specifications is known as 3GPP R99, which was functionally frozen in December 1999. The 3GPP R99 implementation offers the same services with those of GSM Phase 2+ (GPRS/EDGE). That is, all the same supplementary services are available; teleservices and bearer services have different implementation but this is not visible to the subscriber. The 3G network in this phase may offer some other services not available in GSM, for example, a video call. The second phase known as 3GPP Release 4 introduces all-IP in the core network allowing separation of call control and signaling from the actual connection or media used on the core network (CN) side to transport circuit switched (CS) services such as voice. In the CN CS domain actual user data flow passes through Media Gateways (MGW), which are elements that maintain the connection and perform switching functions when required. The whole process is controlled by a separate element evolved from MSC/VLR called MSC server. One MSC server can handle numerous MGWs thus making the CN CS domain scalable. This approach is also referred to as soft switching. Release 4 Specifications were frozen in March 2001. The 3GPP Release 5 then introduces a new element called the IP Multimedia Subsystem (IMS) for unifying the methods to perform IP based multimedia services. Multimedia service is a scenario in which more than one service type component is combined on one physical connection to a user such as voice along with image or video. In Release 5 of the 3GPP specifications, the notion of all-IP is introduced, extending IP transport to the access network as well. This extends the IP mode communication all the way to the radio access network including the circuit switched domain. So, a voice call from UE to PSTN is transported through UTRAN as packets and from the GGSN the VoIP is routed to the PSTN via IMS, which provides the required conversion functions. Release 5 also introduces Wideband AMR, as well as HSDPA. HSDPA service is a new evolution in the air interface for providing high-speed data rates on the downlink. HSDPA provides integrated voice on a dedicated channel and high-speed data on a downlink shared channel on the same carrier, which allows data rates of up to 14.4 Mbps. HSDPA is primarily deployed for dense urban and indoor coverage. Release 5 Specifications were frozen in June 2002. A similar enhancement is introduced on the uplink side in Release 6 for offering high-speed data rates on the uplink, HSUPA. Release 6 also includes wireless LAN/UMTS inter-working, Multimedia Broadcast/ Multicast Service (MBMS), network sharing, and the Push services.

From the user terminal point of view, the network is basically the same in the various developmental phases, except for some new service capabilities such as HSDPA that will require new capabilities in the terminal for using the service. The major changes introduced by the various releases of the UMTS specifications occur within the network and are in the transport technologies, and the new flexibilities and efficiencies provided in operating the network. For instance, release 1999 uses ATM as the transport technology, whereas in 3GPP R4, and R5, ATM is swapped withv IP.

1.2 3G Challenges

The current deployment of UMTS networks is not in many cases ubiquitous and is only concentrated in the congested urban business areas. They are used to provide either the special higher rate data services or increased capacity for handling the voice traffic in specific locations and are therefore complementary and supplemental to the GSM networks. The GSM networks are anticipated to stay around and even continue to grow and expand for at least the next five years given the huge investments already made by the operators in the GSM infrastructure networks and their fine capability to handle voice, though not with the same spectral efficiency as the WCDMA. This means that the island deployment of UMTS networks will be the trend for some time to come, and hence the requirement for the seamless roaming, handover, and inter-operation with the existing GSM networks to provide service coverage continuity and load sharing. Therefore, the elaborate inter-operability and coordination mechanisms and features provided by the equipment need to be exploited by the network planners to effectively result in the pooling of the resources, and hence result in the most efficient utilization of the limited expensive radio spectrums. Moreover, for uniform service quality provisioning, prior optimization of existing GSM/GPRS networks may be necessary to provide the same service quality as in WCDMA in inter-system roaming.

On the other hand, the incumbent GSM operators can exploit their existing GSM network infrastructures in multiple ways to facilitate cost effective optimal planning of UMTS in their networks. These include substantial radio base station co-location to save on site costs, sharing of access transmission facilities to achieve higher trunking efficiencies, and use of network provided radio propagation measurements. Site co-location brings new challenges for efficient antenna sharing solutions, and antenna placement configurations that can provide the proper isolation between the GSM and UMTS systems. The W-CDMA system particularly can be impacted by interference caused by GSM systems, if proper RF isolation measures are not taken in co-siting scenarios. Meanwhile before any co-site deployments, the existing GSM radio access facilities can be used to obtain radio propagation related measurements to characterize path loss and interference geometries to guide link budgeting and site engineering for a UMTS overlay scenario. Interference is a major factor that impacts both the coverage and capacity in CDMA based networks due to the tight frequency re-use of 1. Therefore, having an accurate realistic picture of the RF interference geometry resulting from candidate sites that are selected in sets is highly critical before actual deployment, to make sure that adequate cell isolation is obtained.

In addition to the concerns over interference caused from other cells, intra-cell multi-user interference inherent to CDMA systems results in a dependency between the cells coverage and its capacity (load). This situation makes the radio network planning more complex than in 2G systems. This additional complexity means that site location and dimensioning can no longer be performed based on coverage consideration alone, or capacity adjustment left to later stages. The traffic profile and distribution will have to enter the planning phase from the very beginning to make sure that sites are positioned and dimensioned to achieve a proper balance between the expected coverage and the capacity (load) to be handled. Coverage is also not uniform for all services due to the bit-rate and quality dependent power requirements. Therefore layered architectures based on the use of micro-cells, indoors, and macro-cells need to be implemented to provide efficiently the necessary coverage and capacity for multi-rate services. The coverage limitations imposed by the cell capacity also result in the consideration of using multi-carriers to split the traffic and alleviate the multi-user interference within the same cell, and/or between the cell layers, in order to provide high capacity and throughput. The multi-layer and multi-band architectures will require efficient inter-layer and inter-band handover and traffic distribution mechanisms, and the RF planning and dimensioning of each layer.

Meanwhile, recent developments in the core network technologies have provided new design options to separate the call control and signaling hardware from the media switching fabrics. This allows the design of core network architectures that are scaleable for easy network expansion and flexible to handle the multimedia services efficiently. The separation of call control and signaling from the media switching functions, based for instance on soft switching, also paves the way for migration of the core networks to all-IP transport. This provides the framework for the cost efficient long term growth of 3G services.

Yet another challenge in the optimization of 3G networks is the proper tuning and selection of specific versions of transport protocols such as TCP. TCP is used for the reliable end-to-end delivery of IP based data thatare expected to be a significant service in 3G networks. There are certain versions of TCP that are more suitable to handling packet loss and large delay variations, which can occur over the lossy radio links in the mobile environment. Furthermore the parameters within the radio link protocols and selected TCP version should be tuned to utilize efficiently the allocated limited radio spectrum, and achieve high throughput and QoS for IP based application with their unlimited demand for capacity.

The high throughput and capacity demand of the services anticipated for the 3G networks and the interference-limiting environment of the CDMA based systems require highly skilled radio planning practices and the use of spectral efficiency measures. These include receiver and transmitter antenna diversity mechanisms, efficient site sectorisation, selecting antennas with optimum beamwidths and positioning for proper tilt and orientation to provide maximum cell isolation, iterative link budgeting for reasonable cell load plans, providing for adequate cell overlap for soft handover gains while also minimizing the overheads, and use of vendor equipment capacity improvement mechanisms such as interference cancellations, rate adaptations, and smart efficient packet scheduling algorithms that can operate in near real time. Moreover, the higher complexity of the 3G multi-access dynamics, and the multitude of diverse services with varying QoS requirements and performance metrics, bring new challenges in developing effective methods for performance measurement, problem classification, and root cause analysis.

(Continues...)

Excerpted from UMTS Network Planning, Optimization, and Inter-Operation with GSMby Moe Rahnema Copyright © 2008 by John Wiley & Sons, (Asia) Pte Ltd. Excerpted by permission.
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Dettagli dell'edizione

• Editore: IEEE
• Data di pubblicazione: 2008
• Lingua: Inglese
• ISBN 10: 0470823011
• ISBN 13: 9780470823019
• Rilegatura: Copertina rigida
• Numero edizione: 1
• Numero di pagine: 327
• Contatto del produttore: non disponibile
• Persona responsabile: non disponibile