3G Wireless Networks, Second Edition

Chapter 1: Wireless Communications\ 1.1 The Amazing Growth of Mobile Communications\ Over recent years, telecommunications has been a fast-growing industry. This growth can be seen in the increasing revenues of major telecommunications carriers and the continued entry into the marketplace of new competitive carriers. No segment of the industry, however, has seen growth to match that experienced in mobile communications. From relatively humble beginnings, the last 15 years have seen an explosion in the number of mobile communications subscribers and it appears that growth is likely to continue well into the future.\ The growth in the number of mobile subscribers is expected to continue for some years, with the number of mobile subscribers surpassing the number of fixed network subscribers at some point in the near future. Although it may appear that such predictions are optimistic, it is worth pointing out that in the past, most predictions for the penetration of mobile communications have been far lower than what actually occurred. In fact, in several countries, the number of mobile subscribers already exceeds the number of fixed subscribers, which suggests that predictions of strong growth are well founded. It is clear that the future is bright for mobile communications. For the next few years at least, that future means third-generation systems, the subject of this book.\ Before delving into the details of third-generation systems, however, it is appropriate to review mobile communications in general, as well as first- and second-generation systems. Like most technologies, advances in wireless communications occur mainly through a process of steady evolution (although there is the occasional quantum-leap forward). Therefore, a good understanding of third-generation systems requires an understanding of what has come before. In order to place everything in the correct perspective, the following sections of this chapter provide a history and a brief overview of mobile communications in general. Chapter 2, "First Generation (1G)," and Chapter 3, "Second Generation (2G)," provide some technical detail on first- and second-generation systems, with the remaining chapters of the book dedicated to the technologies involved in third-generation systems.\ 1.2 A Little History\ Mobile telephony dates back to 1920s, when several police departments in the United States began to use radiotelephony, albeit on an experimental basis. Although the technology at the time had had some success with maritime vessels, it was not particularly suited to on-land communication. The equipment was extremely bulky and the radio technology did not deal very well with buildings and other obstacles found in cities. Therefore, the experiment remained just an experiment.\ Further progress was made in the 1930s with the development of frequency modulation (FM), which helped in battlefield communications during the Second World War. These developments were carried over to peacetime, and limited mobile telephony service became available in the 1940s in some large cities. Such systems were of limited capacity, however, and it took many years for mobile telephone to become a viable commercial product.\ 1.2.1 History of First-Generation Systems\ Mobile communications as we know it today really started in the late 1970s, with the implementation of a trial system in Chicago in 1978. The system used a technology known as Advanced Mobile Phone Service (AMPS), operating in the 800-MHz band. For numerous reasons, however, including the break-up of AT&T, it took a few years before a commercial system was launched in the United States. That launch occurred in Chicago in 1983, with other cities following rapidly.\ Meanwhile, however, other countries were making progress, and a commercial AMPS system was launched in Japan in 1979. The Europeans also were active in mobile communications technology, and the first European system was launched in 1981 in Sweden, Norway, Denmark, and Finland. The European system used a technology known as Nordic Mobile Telephony (NMT), operating in the 450-MHz band. Later, a version of NMT was developed to operate in the 900-MHz band and was known (not surprisingly) as NMT900. Not to be left out, the British introduced yet another technology in 1985. This technology is known as the Total Access Communications System (TACS) and operates in the 900-MHz band. TACS is basically a modi-fied version of AMPS.\ Many other countries followed along, and soon mobile communications services spread across the globe. Although several other technologies were developed, particularly in Europe, AMPS, NMT (both variants), and TACS were certainly the most successful technologies. These are the main first-generation systems and they are still in service today.\ First-generation systems experienced success far greater than anyone had expected. In fact, this success exposed one of the weaknesses in the technologies—limited capacity. Of course, the systems were able to handle large numbers of subscribers, but when the subscribers started to number in the millions, cracks started to appear, particularly since subscribers tend to be densely clustered in metropolitan areas. Limited capacity was not the only problem, however, and other problems such as fraud became a major concern. Consequently, significant effort was dedicated to the development of second-generation systems.\ 1.2.2 History of Second-Generation Systems\ Unlike first-generation systems, which are analog, second-generation systems are digital. The use of digital technology has a number of advantages, including increased capacity, greater security against fraud, and more advanced services.\ Like first-generation systems, various types of second-generation technology have been developed. The three most successful variants of second-generation technology are Interim Standard 136 (IS-136) TDMA, IS-95 CDMA, and the Global System for Mobile communications (GSM). Each of these came about in very different ways.\ 1.2.2.1 IS-54B and IS-136\ IS-136 came about through a two-stage evolution from analog AMPS. As described in more detail later, AMPS is a frequency division multiple access (FDMA) system, with each channel occupying 30 KHz. Some of the channels, known as control channels, are dedicated to control signaling and some, known as voice channels, are dedicated to carrying the actual voice conversation.\ The first step in digitizing this system was the introduction of digital voice channels. This step involved the application of time division multiplexing (TDM) to the voice channels such that each voice channel was divided into time slots, enabling up to three simultaneous conversations on the same RF channel. This stage in the evolution was known as IS-54 B (also known as Digital AMPS or D-AMPS) and it obviously gives a significant capacity boost compared to analog AMPS. IS-54 B was introduced in 1990.\ Note that IS-54 B involves digital voice channels only, and still uses analog control channels. Thus, although it may offer increased capacity and some other advantages, the fact that the control channel is analog does limit the number of services that can be offered. For that reason, among others, the next obvious step was to make the control channels also digital. That step took place in 1994 with the development of IS-136, a system that includes digital control channels and digital voice channels.\ Today AMPS, IS-54B, and IS-136 are all in service. AMPS and IS-54 operate only in the 800-MHz band, whereas IS-136 can be found both in the 800-MHz band and in the 1900-MHz band, at least in North America. The 1900-MHz band in North America is allocated to Personal Communications Service (PCS), which can be described as a family of second-generation mobile communications services.\ 1.2.2.2 GSM\ Although NMT had been introduced in Europe as recently as 1981, the Europeans soon recognized the need for a pan-European digital system. There were many reasons for this, but a major reason was the fact that multiple incompatible analog systems were being deployed across Europe. It was understood that a single Europe-wide digital system could enable seamless roaming between countries as well as features and capabilities not possible with analog systems. Consequently, in 1982, the Conference on European Posts and Telecommunications (CEPT) embarked on developing such a system. The organization established a group called (in French) Group Spéciale Mobile (GSM). This group was assigned the necessary technical work involved in developing this new digital standard. Much work was done over several years before the newly created European Telecommunications Standards Institute (ETSI) took over the effort in 1989. Under ETSI, the first set of technical specifications was finalized, and the technology was given the same name as the group that had originally begun the work on its development—GSM.\ The first GSM network was launched in 1991, with several more launched in 1992. International roaming between the various networks quickly followed. GSM was hugely successful and soon, most countries in Europe had launched GSM service. Furthermore, GSM began to spread outside Europe to countries as far away as Australia. It was clear that GSM was going to be more than just a European system; it was going to be global. Consequently, the letters GSM have taken on a new meaning—Global System for Mobile communications.\ Initially, GSM was specified to operate only in the 900-MHz band, and most of the GSM networks in service use this band. There are, however, other frequency bands used by GSM technology. The first implementation of GSM at a different frequency happened in the United Kingdom in 1993. That service was initially known as DCS1800 since it operates in the 1800- MHz band. These days, however, it is known as GSM1800. After all, it really is just GSM operating at 1800 MHz.\ Subsequently, GSM was introduced to North America as one of the technologies to be used for PCS—that is, at 1900 MHz. In fact, the very first PCS network to be launched in North America used GSM technology.\ 1.2.2.3 IS-95 CDMA\ Although they have significant differences, both IS-136 and GSM use Time Division Multiple Access (TDMA). This means that individual radio channels are divided into timeslots, enabling a number of users to share a single RF channel on a time-sharing basis. For several reasons, this technique offers an increase in capacity compared to an analog system where each radio channel is dedicated to a single conversation. TDMA is not the only system that enables multiple users to share a given radio frequency, however. A number of other options exist—most notably Code Division Multiple Access (CDMA).\ CDMA is a technique whereby all users share the same frequency at the same time. Obviously, since all users share the same frequency simultaneously, they all interfere with each other. The challenge is to pick out the sig-nal of one user from all of the other signals on the same frequency. This can be done if the signal from each user is modulated with a unique code sequence, where the code bit rate is far higher than the bit rate of the information being sent. At the receiving end, knowledge of the code sequence being used for a given signal allows the signal to be extracted.\ Although CDMA had been considered for commercial mobile communications services by several bodies, it was never considered a viable technology until 1989 when a CDMA system was demonstrated by Qualcomm in San Diego, California. At the time, great claims were made about the potential capacity improvement compared to AMPS, as well as the potential improved voice quality and simplified system planning. Many people were impressed with these claims and the Qualcomm CDMA system was standardized as IS-95 in 1993 by the U.S. Telecommunications Industry Association (TIA). Since then, many IS-95 CDMA systems have been deployed, particularly in North America and Korea. Although some of the initial claims regarding capacity improvements were perhaps a little overstated, IS-95 CDMA is certainly a significant improvement over AMPS and has had significant success. In North America, IS-95 CDMA has been deployed in the 800-MHz band and a variation known as J-STD-008 has been deployed in the 1900-MHz band....

Acknowledgments     xxiIntroduction     xxiiiIntroduction     1The Amazing Growth of Mobile Communications     1A Little History     2History of First-Generation Systems     2History of Second-Generation Systems     3The Path to Third-Generation Technology     54G and Beyond     9Mobile Communications Fundamentals     9Basic Network Architecture     10Air-Interface Access Techniques     13Roaming     18Handoff/Handover     19Mobile Data     20Wireless Migration Options     22Harmonization Process     23Overview of Following Chapters     23References     23First-Generation (1G) Analog     25First Generation (1G)     251G Systems     26General 1G System Architecture     28Typical MTSO Configuration     291G BTS (Cell Site) Configuration     30AMPS Call Setup Scenarios     31Handoff     32Frequency Reuse     34Spectrum Allocation     37Channel Band Plan     371G Systems     40References     40Second Generation (2G)     41Overview     41Enhancements over 1G Systems     46Integration with Existing 1G Systems     46GSM     47TDMA (IS-54/IS-136)     48CDMA     49DECT     52GSM     53GSM Network Architecture     53The GSM Air Interface     58Types of Air-Interface Channels     59Air-Interface Channel Structure     60GSM Traffic Scenarios     62Location Update     62Mobile-Originated Voice Call     64Mobile-Terminated Voice Call     66Handover     68Traffic Calculation Methods     71IS-136 System Description     71The IS-54 Digital Voice Channel     72Control Channel     76MAHO     77Frequency Reuse     78Call Quality     80IS-95 System Description     80Standard CDMA Cell-Site Configurations     81Pilot Channel Allocation     83Forward CDMA Channel      85Reverse CDMA Channel     87Call Processing     88Handoffs     90Pilot Channel PN Assignment     94Link Budget     97Traffic Model     99iDEN (Integrated Dispatch Enhanced Network)     102WiDEN     113CDPD     113Summary     115References     115Third Generation (3G) Overview     119Introduction     119Universal Mobile Telecommunications Service (UMTS)     123Migration Path to UMTS and the Third Generation Partnership Project (3GPP)     124UMTS Services     125UMTS Speech Service     125The UMTS Air Interface     127WCDMA Basics     127Spectrum Allocation     130Overview of the 3GPP Release 1999 Network Architecture     131Overview of the 3GPP Release 4 Network Architecture     133Overview of the 3GPP Release 5 All-IP Network Architecture     135Overview CDMA2000     137Migration Path     137System Architecture     139Spectrum     139TD-CDMA     141Generic TD-CDMA Architecture      141Radio Network     142RAN     142Handover     143Implementation     144TD-SCDMA     144System Architecture     144Channel Structure     145Interference-Mitigation Techniques     146Handover     146Commonality among WCDMA, CDMA2000, TD-CDMA, and TD-SCDMA     147References     148The Evolution Generation (2.5G)     151What Is 2.5G?     151Enhancements over 2G     152Technology Platforms     153General Packet Radio Service (GPRS)     154GPRS Services     154GPRS User Devices     155The GPRS Air Interface     156GPRS Control Channels     157GPRS Network Architecture     158GPRS Traffic Scenarios     163Inter-SGSN Routing Area Update     171Traffic Calculation and Network Dimensioning for GPRS     173Enhanced Data Rates for Global Evolution (EDGE)     175The EDGE Network Architecture     176AMR Half-Rate Traffic Channels     178GSM/GPRS/EDGE Traffic Dimensioning     181High-Speed Circuit Switched Data (HSCSD)     182CDMA2000 (1xRTT)     182Deployment Issues     183System Architecture     185Frequency Planning     188Handoff     188Traffic Calculation Methods     189Deployment     190WAP     192Short Message Service (SMS)     193Migration Path from 2G to 2.5G to 3G     194References     194Universal Mobile Telecommunications Service (UMTS)     197Introduction     197UMTS Basics     197The WCDMA Air Interface     199Uplink Spreading, Scrambling, and Modulation     199Downlink Spreading, Scrambling, and Modulation     204WCDMA Air-Interface Protocol Architecture     207WCDMA Channel Types     211Power Control in WCDMA     218User Data Transfer     221The UTRAN Architecture     223Functional Roles of the RNC     227UTRAN Interfaces and Protocols     227Establishment of a UMTS Speech Call     234UMTS Packet Data (R99)     236High-Speed Packet Data     239HSDPA      239HSUPA     245Handover     246UMTS Core Network Evolution     248The 3GPP Release 4 Network Architecture     248The 3GPP Release 5 IP Multimedia Domain     251References     252CDMA2000     255Radio and Network Components     258Packet Data Serving Node (PDSN)     260Authentication, Authorization, and Accounting (AAA)     261Home Agent     261Router     261Home Location Register (HLR)     261Base Transceiver Station (BTS)     262Base-Station Controller (BSC)     263Network Structure     263Packet-Data Transport Process Flow     265Simple IP     268Simple IP with VPN     269Mobile IP (3G)     270Mobile IP with VPN     272Radio Network (IS-2000 1xRTT)     272Forward Channel     275Reverse Channel     277SR and RC     279Power Control     280Walsh Codes     281EVDO     283EVDO Forward Link     286EVDO Reverse Link     287EVDO Revision 0      288EVDO Revision A     289Data Rate     293EVDO Revision B     294Multicast     295MIMO     295BCMCS     295EVDV     296CDMA Channel Allocation     296References     297TD-SCDMA     303Generic TD-SCDMA Architecture     303Core Network     305Release 4     305Release 5     306Radio Network     307Radio Spectrum     308Channel Structure     308Spreading Codes     309Logical Channel     310Codes     311Interference-Mitigation Techniques     312"Smart" Antennas     312Joint Detection     313Terminal Synchronization     313Dynamic Channel Allocation     313RAN Traffic Planning     314Handover     315Implementation     316References     318TD-CDMA     319Generic TD-CDMA Architecture     320Core Network     320Radio Network     322Radio Spectrum     323Channel Structure     323Codes     324Logical Channel     325Interference-Mitigation Techniques     326RAN Traffic Planning     327Handover     330Implementation     331Comparison     333References     333Voice over IP (VoIP) Technology     335Why VoIP?     336The Basics of IP Transport     336VoIP Challenges     337H.323     339H.323 Network Architecture     339Overview of H.323 Protocols     341H.323 Call Establishment     342H.323 Call Release     346The H.323 Fast Connect Procedure     346The Session Initiation Protocol (SIP)     347The SIP Network Architecture     348SIP Call Establishment     350Information in SIP Messages     351The Session Description Protocol     352Distributed Architecture and Media Gateway Control     354The MEGACO Protocol     356VoIP and SS7     363The SIGTRAN Protocol Suite     366Example of SIGTRAN Usage      369VoIP Quality of Service     369The Resource Reservation Protocol     369Differentiated Service     372Multi-Protocol Label Switching     372References     373Broadband     375WiFi (802.11)     375802.11b     378802.11g     378802.11a     378802.16     379802.16     380802.16d     384802.16e     384802.16x Specifications     385Bluetooth     385Cable Systems     386References     3883G System RF Design Considerations     391RF System Design Procedures     394Planning Process Flow     395New Wireless System Procedure     395Methodology     399RAN Migration Methodology     399Spectrum     400Radio Access Method     401Traffic Forecast     402Legacy System     402Subscriber Migration Process     403Link Budget     403Propagation Models     406Free Space     408Hata      408Cost231-Walfisch/Ikegami     409Cost231-Hata     411Quick     412Tower-Top Amplifiers     413RF Design Guidelines     414Traffic Projections     415Traffic Tables (Appendix)     416Radio Traffic Projections     418Radio Voice Traffic Projections     419Radio Data Traffic Projection     419Cell-Site Design     424Search Area     424Site Qualification Test (SQT)     425Site Acceptance (SA)     426Site Rejection (SR)     428Site Activation     428FAA Guidelines     429EMF Compliance     429RF Design Report     431Cover Sheet     431Executive Summary     431Revision     431Table of Contents     431Introduction     432Design Criteria     432Existing System Overview     432Coverage Objectives     432Coverage Quality     433RF System Growth Requirements     433Intersystem Coverage     433Link Budget      433Analysis     434Summary of Requirements     434References     434Network Design Considerations     437Traffic Forecasts     438Subscriber Forecast     439Voice Usage Forecast     439Data Usage Forecast     440Build-Ahead     441Network Node Dimensioning     442BSC Dimensioning     442UMTS RNC Dimensioning     443CDMA2000 BSC     444MSC Dimensioning     444SGSN and GGSN Dimensioning     445PDSN and Home Agent Dimensioning     446Dimensioning of Other Network Elements     446Interface Design and Transmission Network Considerations     447Placement of Network Nodes and Overall Network Topology     449Cost Optimization     450Considerations for All-IP Networks     451Network Reliability Considerations     452Service Treatments     452TDM/IP/ATM Considerations     454TDM Switching     455Switching Functions     455Circuit Switches     456Space-Division Switching     456Time-Division Switching      456Circuit-Switching Hierarchy     458Packet Switching     458IP Networks     459IP Addressing     460Soft Switches     463ATM     465ATM Networks     468ATM Design Aspects     469Facility Sizes     471Demand Estimation     471VoIP     472OSI Levels     474Final Report     474Summary     475References     475Antenna System Selection     477Base-Station Antennas     478Performance Criteria     479Diversity     482Cross-Pole Antennas     485Dual-Band Antenna     487Intelligent Antennas     488MIMO     490dBi and dBd     490References     491UMTS System Design     493Network Design Principles     493RF Coverage Analysis     494Link Budgets     496RF Capacity Analysis     501Calculating Uplink Cell Load     503Downlink Cell Load     507Load Sharing      511Design of the Radio Access Network     513Iub-Interface Dimensioning     514Determining the Number of RNCs     515Designing the UTRAN Transmission Network     516UMTS Overlaid on GSM     520HSDPA/HSUPA     523References     523CDMA2000 System Design     525Design Methodology     526Deployment Guidelines     5271xRTT     5301xEV-DO     5301xEVDV     530System Traffic Estimation     531Radio Elements     534Antenna Configurations     534BTS     535Channel Element (CE) Dimensioning     536Packet-Data Services (RF Environment)     537Fixed Network Design Requirements     538PDSN     539Packet Zone     539Design Utilization Rates     540IP Addressing     540Traffic Model (1xRTT)     543Walsh Codes     544Packet- Data Rates     553Handoffs     556Search Window     556Soft Handoffs (1xRTT)     556EVDO      558PN Offset Assignment     558Link Budget     5601xRTT     560EVDO     561Sample Basic Designs     564CDMA2000 1xRTT     565EVDO (IS-856)     569CDMA2000 1xRTT with EVDO Overlay     573References     578TD-CDMA and TD-SCDMA System Design     581Design Methodology     582Deployment Guidelines     584System Traffic Estimation     585Radio Elements     589Spectrum     589Antenna Configurations     590Node B     590Fixed Network Design Requirements     591Utilization Rates     593IP Addressing     593Sample Basic Designs     595References     596Communication Sites     599Communication-Site Types     599Macrocell Site     600Omnidirectional Cell Sites     601Directional Cell Site     602Microcells     604Picocell Sites     605Installation     606Cable Runs     606Antenna Mounting      606Diversity Spacing     607Roof Mounting     608Wall Mounting     608Towers     610Stealth     610In-Building and Tunnel Systems     611Antenna System     615In-Building Application     615Tunnel Applications     616Planning     618Intermodulation     619IM Check Procedure     620Colocation     621Isolation Requirements     622Calculating Needed Isolation     624Isolation Requirements     625Free Space     625Antenna Patterns     626Vertical Separation     626Horizontal Separation     628Slant Separation     630Colocation Guidelines     631Colocation Rules     636Communication-Site Checklist     637References     6384G and Beyond     639Technology Path     640IMS     641Convergent Devices     643Smart Phones     643Software Defined Radio (SDR)     644Laptops     645PTT      645Advanced Broadband Wireless Access     645Ultrawideband (UWB)     645Unlicensed Wireless Access (UWA)     646802.20 MBWA     647FOMA and iMODE     652WiBRO     652FWA     652Advanced Wireless Services (AWS)     652Multimedia (Mobile TV)     653MediaFLO     654T-DBM     654DVB-H Digital     654MVNO     655First Responders     655Business Requirements     657References     659Erlang Tables     661=970 12$lErlang B     661=970 12$lErlang C     663Index     665