3g Wireless Technologies

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TABLE OF CONTENTS 1. ABSTRACT ............................................................................................................. 2 2. FIRST GENERATION ANALOG WIRELESS CELLULAR SYSTEMS............... 2 3. SECOND GENERATION DIGITAL WIRELESS CELLULAR SYSTEMS ........... 3 3.1

Time Division Multiple Access (TDMA) ............................................................................3

3.2

Global System for Mobile Communications (GSM).........................................................3

3.3

Code Division Multiple access (CDMA) .............................................................................4

4. THIRD GENERATION -3G- WIRELESS TECHNOLOGIES ............................... 5 4.2

IMT-2000 and 3G System Development.............................................................................5

4.3

3G Systems: Global Wireless Standards Evolution ..........................................................7

4.4

Comparison of 3G Technologies........................................................................................10

5. TECHNICAL ASPECTS OF cdma2000 and W-CDMA THIRD-GENERATION SYSTEMS .................................................................................................................... 11 5.1 North American cdma2000 System.......................................................................................11 5.2

W-CDMA..............................................................................................................................14

5.2.1

ARIB WCDMA..................................................................................................................24

6. Differences Between W-CDMA and cdma2000 ..................................................... 27 6.1 Capabilities of Physical Layer.................................................................................................27 6.2 Forward Link Channel Structure ..........................................................................................28 6.3 Asynchronous Base Station (BS) Mode .................................................................................30

7. TECHNOLOGY SUMMARIES OF 2G AND 3G SYSTEMS................................ 32 8. 2-1/2 SYSTEMS: GPRS, EDGE ............................................................................ 33 8.1

GPRS -General Packet Radio Service ..............................................................................33

8.2

Enhanced Data rates for GSM Evolution (EDGE) .........................................................33

9. 3G AND MOBILE IP ............................................................................................ 34 10.

MARKETING ISSUES ...................................................................................... 34

11.

CONCLUSION................................................................................................... 35

12.

ACKNOWLEDGMENTS AND REFERENCES................................................ 35

13.

3G ACRONYMS ................................................................................................. 37 3G Wireless Technologies By: Josue Valencia December 20, 2000

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1. ABSTRACT 3G is a generic term covering a range of future wireless air interface technologies, including 1 cdma2000, UTRA/W-CDMA, and UWC 136 HS The International Telecommunication Union (ITU), the arm of the United Nations that oversees global telecommunications systems, began studies on globalization of mobile personal communications in 1986. The ITU (an international standards organization) defined the IMT-2000 specification, a set of proposed requirements for 3G terrestrial/satellite wireless systems. Regional standards bodies such as TIA (North America), ARIB (Japan) and ETSI (Europe), developed three major proposals to meet the IMT-2000 specification: cdma2000, UWC 136 HS , and UTRA / W-CDMA. These 3G systems will offer a plethora of telecommunications services characterized by mobility and advanced multimedia capabilities including voice, low and high-bit-rate data, Internet access, and video to mobile and fixed users via a wide range of mobile terminals, operating both in public and private environments. This paper covers the technological aspects of 3G, starting with a brief overview of first generation and second generation wireless technologies. 2-1/2 G Technologies, such as GPRS and EDGE, are also discussed in some detail. Critical marketing aspects of 3G are also presented, touching on key questions for network operators such as: what is the best technological choice? How do I upgrade my network? Should I bid for new spectrum? What new services are possible with 3G that cannot be met with existing technology/infrastructure? Why should I invest in 3G?

2. FIRST GENERATION ANALOG WIRELESS CELLULAR SYSTEMS First Generation analog cellular systems use an air interface access technology known as Frequency Division Multiple Access (FDMA), to provide basic mobile voice telephony. FDMA uses narrowband, 30 Khz channels of spectrum (also known as carriers), each carrying one telephone circuit. The number of calls in a sector is hard limited by the amount of carriers that can be assigned to the available spectrum. Examples of First Generation analog systems are AMPS (used in North America) and TACS (used in certain parts of Europe)

First generation AMPS Analog system. Each user is assigned a 30-Khz carrier during the call. 1

Acronyms are expanded in the Acronyms section at the end of this document 3G Wireless Technologies By: Josue Valencia December 20, 2000

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3. SECOND GENERATION DIGITAL WIRELESS CELLULAR SYSTEMS Using digital techniques, Second Generation digital wireless systems offer increased voice capacity, increased security, low bit rate data and regional roaming. The main 2G digital wireless technologies are CDMA and TDMA, widely deployed in North America and some parts of the world, and GSM, deployed throughout Europe and many other parts of the world. These 2G air interface access technologies are briefly described below.

3.1

Time Division Multiple Access (TDMA)

TDMA divides the 30 Khz carrier frequency into a number of time slots, each of which constitutes an independent telephone circuit. The North American Second-generation digital TDMA system supports 3 full-rate telephone circuits in each of the 30 KHz carriers, effectively achieving a 3:1 capacity improvement over the analog AMPS system.

2G Digital TDMA System. Each 30 Khz carrier frequency is time-shared by three users, each using a different time slot

3.2

Global System for Mobile Communications (GSM)

GSM is similar to TDMA in that it divides each carrier frequency into a number of time slots. GSM utilizes wider band (200 KHz) carrier frequencies, and each of these frequencies support 8 timeslots. GSM was adopted in Europe as its primary standard for Second Generation wireless communications systems not only to increase capacity, but mainly to address the roaming difficulties caused by the proliferation of incompatible first generation analog standards throughout all of Europe.

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GSM Different Times

...8 slots... 2G digital GSM system. Each 200 Khz carrier frequency is time-shared by 8 users, each using a different time slot

3.3

Code Division Multiple access (CDMA)

CDMA changes the rules in that multiple users can be coincident both in frequency and in time. In CDMA, multiple callers share a wideband 1.25 MHz radio channel simultaneously. CDMA uses spread spectrum modulation schemes, and unique codes to differentiate each individual call from among all others. Once the air limitations of one CDMA carrier are reached, one or more additional CDMA carriers can be deployed, each of them supporting several users simultaneously. Another outstanding advantage of CDMA over other 2G air interface is that it has a reuse factor of N=1, meaning that the same CDMA carrier can not only be reused in adjacent cell sites, but also in every sector of the same cell site. This feature not only increases capacity, but also facilitates tremendously the design of frequency plans for CDMA wireless systems. In fact, CDMA achieves the greatest spectral efficiency among all 2G technologies, and the concepts of CDMA constitute the foundation for the major 3G air interface access technologies, some of which will be described later in this paper.

2G digital CDMA system. Each 1.25 Mhz carrier is shared by multiple users at the same time. Each user is assigned a unique code. Multiple 1.25 Mhz CDMA carriers can be deployed to increase system capacity, up to the limits of spectrum availability.

3G Wireless Technologies By: Josue Valencia December 20, 2000

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4. THIRD GENERATION -3G- WIRELESS TECHNOLOGIES Today s 2G networks are primarily voice centric. Data services such as e-mail retrieval and Web access are possible only at data rates of 14.4 kilobits per second (Kbps) at most. By contrast, 3G systems will be primarily data and applications centric, combining high-speed mobile access with packet-based Internet Protocol (IP). Data rates as high as 2 Megabits per 2 second will be possible in 3G (indoors) , enabling high-speed data and mobile multimedia services that include voice, video, low and high-bit-rate data, internet access, location-based services, and access to information and services, anytime, anywhere. Many of these new features and services will require cooperation from other enabling technologies such as Bluetooth and WAP, as well as a range of new terminals with voice, data and multimedia features including video capabilities. Because the IMT-2000 goal of 3G may be impossible to achieve, many of these new terminals may also be compatible with multiple 3G standards, thereby supporting global roaming. Regarding harmonization, it would be difficult to predict a system that stems from cdma2000 and UTRA/W-CDMA harmonization. Europe would mostly like to protect its huge investment in GSM networks, while IS-95 operators would also want investment protection, backward compatibility with their present systems, and competition advantage. IS-136 operators cannot afford to move to CDMA, and their strategy for global roaming is by merging with Enhanced Data rate for GSM Evolution (EDGE), and perhaps ultimately W-CDMA, taking advantage of the GSM footprint in the interim.

4.2

IMT-2000 and 3G System Development

The studies on globalization of personal communications began in 1986 by ITU to identify the long-term spectrum needs for the future 3G mobile telecommunications systems. ITU defined the International Mobile Telephone-2000 (IMT-2000) specification, a set of proposed requirements for 3G terrestrial/satellite wireless systems, including a wide range of voice, data, and multimedia services. The IMT-2000 proposed specifications include global roaming, and speeds for data transport equal to 144 kbps for vehicular transmission, 384 kbps for pedestrian traffic, and two Mbps for fixed indoor use. By June, 1998, ten Radio Transmission Technologies (RTTs) terrestrial proposals had been submitted for consideration. Shown in the graph below are the IMT-2000 goals for 3G

2

These are peak rates, based on good RF conditions. There is a general misconception that these rates are sustained / per user. Actual data rates depend on demand for the data channels available. 3G Wireless Technologies By: Josue Valencia December 20, 2000

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IMT-2000 Goals for 3G (FPLMTS) ¥Higher data rates

¥Global Mobility ¥Global Roaming ¥Harmonization (3GPP, 3GPP2) ¥Internetworking (IS41/GSM-MAP)

¥Multimedia Services ¥Web-browsing (inter/intranet) ¥Video Conference (net-meeting) ¥File Transfer (ftp) ¥e-mail

¥144kbps (mobile/outdoor) ¥2Mbps (pedestrian/indoor)

¥New Spectrum ¥Core band (WARC1992 - 230MHz) 1885-2025MHz / 2110-2200MHz ¥Additional bands (WARC2000) 1710-1885MHz 2500-2690MHz

In 1992, ITU identified 230 MHz of spectrum in the 2 GHz (1.8 to 2.2 GHz) band to implement the IMT-2000 specification on a worldwide basis, for the satellite and terrestrial components. Because of the differences in spectrum assignments around the globe, today s 3G systems are designed around the available regional spectrum, while still being considered as compliant with IMT-2000 requirements. Shown below are the spectral allocations around the world, including the IMT-2000 spectrum allocation.

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IMT- 2000 Spectrum Allocation Requirements ITU

IMT

(WARC 1992 Decision) 1885

1980

IMT

MSS *

MSS

MSS *

2110

2010 2025

MSS * After 2005

MSS

2160 2170

2200

1920

Japan

PS BS TDD 3G System MSS Sys FDD

PHS

(Existing)

1885 1895 1918.1

Europe

DECT

1980

UMTS

PS BS 3G System FDD

2010 2025

MSS

2110

MSS

2170

UMTS

UMTS

2200

MSS

UMTS

(Proposed) 1880

1890 1920

1980

2010

2040

2110

2170

2200

2150

USA

PCS PS BS

(Existing) 1850

Canada

PCS Unlicensed

1910

PCS PS BS

PCS BS PS

1930

PCS Unlicensed

PM BA

MSS

1990

PCS BS PS

2025

2110

ET

2130

MSS

2160

FIXED

MSS

2200

2230 PS -

Personal Station

BS -

Base Station

TDD -

Time Division Duplex

MSS -

Mobile Satellite Systems

UMTS - Universal Mobile Telephone System FDD -

Frequency Division Duplex

PM -

Public Mobile

ET -

Emerging Technology

BA -

Broadcast Auxiliary (ENG)

MSS

(Existing) 1850

4.3

1910

1930

1990

2025

2110

2160

2200

3G Systems: Global Wireless Standards Evolution

The International Telecommunications Union (ITU) has accepted five standards that fit its International Mobile Telephone-2000 (IMT-2000) requirements of global roaming and data speeds. Three are expected to govern wireless networks in most of the world: 4.3.1

Cdma2000

cdma2000 is also known as cdma2000 Multi-carrier (1X and 3X) —this North American system offers an evolutionary path for providers who have based their CDMA networks on the ANSI-95 standard, thus protecting capital investment. Cdma2000 can also be implemented by any carrier considering a 3G network deployment whether they operate an ANSI-95 network or not. Some equipment providers may skip the 3G3X system in favor of 1XEV, a high-data rate system based on HDR (acronym for High Data Rate), as shown in the graph below. 1XEV is divided into two phases: 1XEV-DO (Data Only) and 1XEV-DV (Data and Voice.) 3G Wireless Technologies By: Josue Valencia December 20, 2000

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CDMA2000 Technology Summary • • • • • • • • • • • • • • • •

4.3.2

Synchronous System (need GPS) Fast Forward Link Power Control (800Hz) Channel Coding: Convolutional and Turbo for data Modulation: QPSK (instead of BPSK) Spreading Codes: Walsh (variable length) Quasi Orthogonal Functions (increase Walsh codes) Coherent reverse link with continuous pilot (low Eb/No operation) Multi-carrier system: N * 1.25MHz for backward compatibility and coexistence with IS95 Different Frame Lengths (5, 20 msecs) Antenna Transmission Diversity (OTD) Auxiliary Pilot for Smart Antennas Enhanced Access Channel Enhanced Paging Channel (Quick paging) Improved Handoff 3G-1X: up to 144kbps 3G-3X (and above): up to 2Mbps indoor

UWC 136 HS

Also known as TDMA Single Carrier —This 3G system is based on IS-136 and Enhanced Data rate for GSM Evolution (EDGE) technology, the TDMA/GSM migration path to packet data, including VoIP (EDGE will be described in detail in a later section) The UWC is targeting the TIA-IS-136 evolution to meet IMT-2000 requirements for 3G, with an initial deployment within 1 MHz spectrum allocation. UWC-136 meets these targets via High Level Modulation (HLM) to the existing 30 kHz carrier (IS-136+), and by defining a complementary wider-band TDMA carrier with bandwidths of 200 kHz ( IS-136 HS {vehicular/outdoor}- same as EDGE) and 1.6 MHz (IS-136 HS {indoor} - same as FMA1 without spreading). IS-136+ will provide data rates up to 64 kbps, and IS-136 HS up to 2 Mbps (indoor). IS-136 based TDMA systems may ultimately evolve into Wide-band Code Division Multiple Access (WCDMA), by first evolving into the 2-1/2 EDGE system (refer to graph below) UWC 136 HS Technology Summary • • • • • •

200kHz carrier, 8 TDMA slots up to 144kbps for high mobility up to 384kbps for pedestrian/low mobility Multiple Modulation Formats (16QAM, QPSK, GMSK) Link Adaptation Techniques 1.6MHz carrier: up to 2Mbps (indoor)

3G Wireless Technologies By: Josue Valencia December 20, 2000

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4.3.3

UTRA / W-CDMA

The two major 3G European systems are UTRA (outdoor environment) and TD/CDMA indoor environment). Both systems support wider bandwidth, enhanced services and backward compatibility to 2G systems. The European UTRA wideband —CDMA activities were initially conducted in the FRAMES project and later as one of the proposals in the SMG committee. ETSI SMG reached consensus in January 1998 to use UTRA for outdoors (wide area service) applications, operating in FDD mode: 1920-1980 MHz in the reverse link, and 2110 to 2170 in the forward link. TD/CDMA was chosen for private indoor services, operating in TDD mode with unpaired frequency bands, using the spectrum in the range 2010 to 2025 MHz. Europe and Japan will use a harmonized standard for outdoor environments, based on Wideband CDMA. The standard is known as UTRA/W-CDMA: UTRA for ETSI (Europe) and W-CDMA for ARIB (Japan). The Japanese W-CDMA (ARIB) system was initially proposed by NTT DOCOMO, based on core A (CDMA-FDD). UTRA/W-CDMA is based mostly on the Universal Mobile Telecommunications System (UMTS) 3G standard —this is the Direct-Spread European 3G version, adopted by the European Telecommunications Standards Institute (ETSI), and intended mainly for the evolution of GSM networks. In Europe, UTRA/W-CDMA is aimed at supporting a substantially wider and enhanced range of services as compared to the current 2G GSM system, including multimedia and high-speed data services. These enhancements will be achieved through an evolution path, to capitalize on the investment in GSM infrastructure. In Japan, evolution of the GSM platform is planned due to its flexibility and widespread use of GSM around the world. The service area of the 3G system will be overlaid with the existing 2G (PDC) system. The 3G system will connect and inter-work with a 2G system through an interworking function (IWF). IMT2000-PDC dual mode terminals as well as IMT2000 single mode terminals will be deployed. UTRA / W-CDMA Technology Summary • • • • • • • • •

Asynchronous system (no GPS timing is required) Wideband DS CDMA (5MHz), FDD 1.024, 4.096, 8.192, 16.384Mcps Power Control: Closed loop 1600bps Speech Coding: Adaptive multi-rate Channel Coding: Convolutional, RS for data Circuit or Packet data Pilot on both Reverse/Forward links Pilot symbol assisted demodulation (per user)

The graph in section 4.4 below shows the proposed global wireless standards evolution towards 3G 3G Wireless Technologies By: Josue Valencia December 20, 2000

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4.4

Comparison of 3G Technologies

Global Wireless Standards Evolution 1xEV Phase 1 HDR IS-95-A

cdma2000 1X MC

IS-95-B ¥64 kbps Packet ¥ RF Backward Comp.

¥14.4 kbps Circuit

¥ 2.4 Mbps Packet ¥ RF Backward Comp.

¥9.6 kbps Circuit

¥ 384+ kbps Packet ¥ RF Backward Comp.

EDGE (US) EDGE (Europe)

UWC136HS

¥ 384 kbps Packet

¥ 2Mbps Packet

GSM GPRS

¥9.6 kbps Circuit

¥ 30-40 kbps Packet ¥ RF Backward Comp.

PDC

PDC

¥ Higher Cap Voice/ Data ¥ RF Backward Comp.

cdma2000 3X MC

¥153 kbps Packet ¥ RF Backward Comp.

IS-136

GSM

1xEV Phase 2

W-CDMA (Europe) ¥ 384+ kbps Packet ¥ New RF Spectrum

W-CDMA (Japan)

¥9.6 kbps Circuit ¥28.8 kbps Circuit ¥ RF Backward Comp.

1995

1999

2000

2001

2002

2003+

The main features of the three main 3G air interface technologies are shown in the graph below CDMA2000 Spectrum

W-CDMA

UWC 136HS

Existing PCS, or new IMT New IMT-2000 2000 Spectrum Spectrum Can coexist on the same Cannot coexist with 2G carrier. Allow gradual transition (overlay)

Existing PCS, or new IMT 2000 Spectrum Need separate carriers 2G (30kHz), 3G (200kHz, 1.6MHz)

BTS Synchro

Required

Not Required

Required

Chip Rate

1.024 * (1,4,8,16) Mcps N/A

Power Control

1.2288 * (1,3,6,9,12) Mcps FL : CLPC (800 bps) RL: OLPC + CLPC (800bps)

FL: CLPC (1600bps) RL: OLPC +CLPC (1600bps)

N/A

Frame Length

5, 20 msec

10 msec

4.615 msec

2G/3G Coexistence

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5. TECHNICAL ASPECTS OF cdma2000 and W-CDMA THIRD-GENERATION SYSTEMS 5.1 North American cdma2000 System The cdma2000 system represents the evolution of the TIA/EIA-95-B family of standards to meet the ITU IMT-2000 3G requirements. Cdma2000 supports 3G services as defined by the International Telecommunications Union (ITU) s IMT-2000 specification. cdma2000 is a decidedly efficient 3G standard for the delivery of high bandwidth data and high capacity voice services. Cdma2000 will be implemented in the existing frequency bands of CMDA at 800 and 1900 MHz, as well as in new spectrum at 2GHz in Japan. The cdma2000 system is divided into two phases commonly known as 1X and 3X. Phase one provides support for the cdma2000 1X air interface - providing average data rates of 144 kbps, and twice the system capacity of IS-95 CDMA systems, achieved via technological improvements (discussed in detail later) such as coherent detection on the uplink, and fast closed loop power control on the downlink-dedicated channels with 800 updates per second. Phase two incorporates additional support for 3X systems, providing for data rates up to 2Mbps. Phase 1 cdma2000 1X The IS-2000 standard (cdma2000 1X) has been completed and published by the Telecommunications Industry Association (TIA). 1X offers approximately twice the voice capacity of cdmaOne, average data rates of 144 kbps, backward compatibility with cdmaOne networks, and other performance improvements. 1X refers to cdma2000 implementation within existing spectrum allocations for cdmaOne 1.25 MHz carriers. The technical term is derived from N =1 (i.e. use of same 1.25 MHz carrier as in cdmaOne) and the 1x means one times 1.25 MHz (RTT refers to Radio Transmission Technology).

3G Wireless Technologies By: Josue Valencia December 20, 2000

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1X can be implemented in existing spectrum or in new spectrum allocations. A cdma2000 — 1X network will also introduce simultaneous voice and data services, low latency data support and other performance improvements. Phase 2 cdma2000 - 3X The IS-2000-A standard (cdma2000-3X) offers even higher capacity than 1X, data rates of up to 2 Mbps, backward compatibility with both 1X and cdmaOne deployments, and other performance enhancements. 3X can also be implemented in existing or new spectrum allocations, but it utilizes a broader band of spectrum. The term 3X refers to N = 3 (i.e. use of three 1.25 MHz carriers). There are currently two implementations of 3X identified in the standard. the Multi-Carrier mode utilizes three 1.25 MHz carriers to deliver 3G services, while the Direct Sequence mode utilizes one 3.75 MHz carrier to deliver the same services. The mode implemented would largely depend on the operator s existing spectrum allocations and usage. With cdma2000 3X operators will be able to offer even higher average and peak data rates from their networks — up to 2 Mbps.

cdma2000 Packet Core Network The standards for a CDMA packet core network are being developed by the TR45.6 working group of the TIA. These standards are being developed by using existing standards from the IEFT (Internet Engineering Task Force) on Mobile IP.

Cdma2000 incorporates advanced antenna technologies, and supports advanced services that are not practical in other systems (e.g., high speed circuit data B-ISDN or H.224/223 teleservices). Future Cdma2000 Equipment providers claim that the cdma2000 system can be operated economically in a wide range of environments including outdoor megacell (>35 km radius), outdoor macrocells (1-35 km radius), indoor/outdoor microcells (up to 1 km radius), and indoor/outdoor picocell (<50 m radius). Operating environments include indoor office environment, wireless local loop, vehicular, and mixed vehicular/indoor/outdoor environments. Cdma2000 uses a chip rate of 3.6864 Mchip/s for 5 MHz bandwidth with a direct spread downlink (forward link), and a 1.2288 Mchip/s chip rate for a multicarrier downlink. The multicarrier approach partitions the downlink spectrum into multiple 1.25 MHz carriers. This option is useful for overlaying a cdma2000 system over an existing cdmaOne network.

3G Wireless Technologies By: Josue Valencia December 20, 2000

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Moreover, the multicarrier approach provides transmit diversity on the downlink. The uplink (reverse link) only supports the direct spread approach. As with IS-95B, the spreading code of cdma2000 is generated using different phase shifts of the same PN-sequence. This is possible due to the synchronous network operation. A bandwidth of 5 MHz can resolve a greater degree of multipath propagation than a narrower bandwidth, increasing diversity and improving system performance. Larger bandwidths of 10, 15, and 20 MHz have been proposed to support the highest data rates more efficiently. A complex spreading is used to reduce peak-to-average power and improve power efficiency. The spreading modulation can be either balanced or dual-channel QPSK. In the balanced QPSK spreading, the same data signal is divided into I and Q channels. In dual-channel QPSK spreading, the symbol streams on the I and Q channels are independent of each other. On the downlink, QPSK data modulation is used to save code channels. QPSK data modulation allows the use of the same orthogonal sequence for both I and Q channels. 5.1.1 Radio Features of cdma2000 cdma2000 inherits many built-in merits and features of the world s first CDMA cellular system (IS95 based CDMA-One) and adds on many new feature. The major features in the radio aspect include the following. 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12)

Soft Handoff Inter-frequency Handoff Power Control Burst Control (High Speed Data) Turbo Codes (High Speed Data) Auxiliary Pilots Forward Orthogonal Transmit Diversity / Forward Multi-carrier Transmit Diversity Variable Spreading Walsh Codes Inhibit Sense Multiple Access Optimized Common Channels Overlay Deployment with 2G IS-95 Hierarchical Cells

Soft handoff (SHO) has been one of the most important features of CDMA systems compared to other access technologies such as TDMA. In the reverse link, SHO makes possible that the instantaneous strongest base station (BS) can power down the mobile (MS) so minimum interference is achieved thereby increasing system capacity. In the forward link, as MS approaches the common areas of 2 or more BS, SHO facilitate the forward diversity gain (where MS uses soft combining in its rake receivers). However, due to many deployment or implementation constraints, there can be areas with too many roughly equal strength BS, which causes excessive SHO which in turn can degrade forward link capacity. A possible cure for the excessive SHO scenario has been proposed in IS-95B and also in cdma2000, namely the dynamic SHO threshold mechanism. Traditionally, determination as to whether to add a BS into SHO is by measuring the Ec/I0 (i.e., the fraction of receive power from a specific BS pilot) compared to a fixed threshold (e.g., T_add in IS-95).

3G Wireless Technologies By: Josue Valencia December 20, 2000

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5.2

W-CDMA

As mentioned previously, The ETSI UMTS Terrestrial Radio Access (UTRA)/FDD W-CDMA European proposal is being harmonized with the Japanese ARIB W-CDMA standard being deployed by NTT DoCoMo. The Future Radio wideband Multiple Access Systems (FRAMES) defines the radio interface(s) for Universal Mobile Telecommunication Systems (UMTS). Since GSM is the most widely used second-generation system in the world, the frequency grid of FMA is made compatible with GSM. This means that FMA carriers must be located in the frequency band with the same resolution as 200 kHz GSM carriers. Two modes of FMA, FMA1 and FMA2 (W-CDMA), have been proposed to ITU. FRAMES partners who are members of Association of Radio Industries and Business (ARIB) have actively contributed to FMA2 concept for Japanese W-CDMA standardization in ARIB. Two options of FMA1 are WB-TDMA (FMA1 without spreading) and TD-CDMA (FMA1 with spreading). The WB-TDMA solution is proposed for frequency-division duplex (FDD) operation in paired frequency bands (1920-1980 MHz [uplink] and 2110-2170 MHz [downlink] ) for the outside vehicular environment, and TD-CDMA is proposed for time-division duplex (TDD) operation in the single frequency band (2010-2025 MHz ) for indoor environment ETSI UMTS Terrestrial Radio Access (UTRA)/FDD proposal based on W-CDMA has the key parameters similar to those of ARIB W-CDMA [5] proposal. Regarding the TDD mode, ARIB WCDMA proposal has the same key parameters as the FDD mode including chip rate, frame length, and modulation/demodulation schemes. The efforts for harmonization are still going on to achieve commonality between W-CDMA/TDD and UTRA/TDD. Although most concepts are shared by both UTRA W-CDMA and ARIB W-CDMA, some differences do exist. Table 1 compares the two systems.

3G Wireless Technologies By: Josue Valencia December 20, 2000

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Table 1 Comparison between ARIB W-CDMA and ETSI UTRA (FDD Mode)

3G Wireless Technologies By: Josue Valencia December 20, 2000

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5.2.1

FMA 2 (W-CDMA)

The UTRA proposal from ETSI, whose parameters are almost harmonized with the Japanese proposal and with the Global CDMA II proposal from the TTA of Korea, is now under the technical harmonization process. The protocol stack of FMA1 and FMA2 are harmonized as much as possible in different layers. In the FMA concept, the goal is to reuse as much of the mode-specific protocols as possible when designing the other mode. Although there are basic differences in radio link control (RLC) and media access control (MAC) between FMA1 and FMA2, it is expected that protocol structure and handling of information exchange can be further harmonized. The logical link control (LLC) provides the same functionality within protocol stack, and it is assumed to be made independent apart from some differences for internal parameters. The radio network layer (RNL) is different for two modes. The radio resource control (RRC) provides some fundamental differences between handoff for FMA2 and mobile assisted hard handoff for FMA1., while most functions common to both FMA modes are provided with Radio Bearer Control (RBC) function. Both RBC and RRC could be presented as a single RRC protocol as well. Radio Interface Protocol Description for WCDMA To utilize capabilities of W-CDMA efficiently, a radio interface protocol has to be well designed to fully incorporate W-CDMA physical layer. In UMTS Terrestrial Radio Access Network (UTRAN), overall protocol structure is split into sub-layers corresponding to OSI layering model. These are: • • • •

Physical layer (PHY, Layer 1) Medium Access Control sub-layer (MAC, lower layer of Layer 2) Radio Link Control sub-layer (RLC, upper layer of Layer 2) Radio Resource Control sub-layer (RRC, Layer 3)

RRC RLC MAC PHY Fig 1 OSI layering model for air interface protocol

The layering model is shown in Fig 1. PHY offers data information transfer service over its W-CDMA radio medium for the upper layers. MAC provides data transfer service for RLC and reallocate radio resources. On request, MAC may also report to its higher layer about traffic volume and quality indication. ARQ functionality is realized in the RLC sub-layer. The retransmission protocol ensures that the optimum utilization of the available radio resources is achieved without incurring excessively long delays. RRC provides general information broadcast and notification service to all mobiles. It also provides services for establishment/maintenance/release of a mobile/UTRAN connection and transfer of messages using this connection. The RRC functionality also includes establishment/reconfiuration/release of a radio access bearer, RRC mobility control (soft/hard handoff procedures). Other radio resource control functions 3G Wireless Technologies By: Josue Valencia December 20, 2000

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fulfilled by RRC are arbitration of the radio resource allocation between the cells, control of requested Quality of Service (QoS), and outer loop power control (setting the target of the closed loop power control). Physical Layer The access to physical layer services is through the use of transport channels via the MAC sub-layer [6]. The transport channel types being defined in UTRAN are Dedicated Channel (DCH), Random Access Channel (RACH), Forward Access Channel (FACH), Downlink Shared Channel (DSCH), Broadcast Channel (BCH) and Paging Channel (PCH). The characteristics of a transport channel are defined by its transport format (or format set), specifying the physical layer processing to be applied to the transport channel, such as coding and interleaving, and any service-specific rate matching as needed. The physical layer operates exactly according to the L1 radio frame timing. A transport block is defined as the data accepted by the physical layer to be jointly encoded. The transport block timing is then tied exactly to this L1 frame timing, e.g.. every transmission block is generated precisely every 10 ms, or a multiple of 10 ms. A mobile can set up multiple transport channels simultaneously, each having own transport characteristics (e.g. offering different error correction capability). Each transport channel can be used for information stream transfer of one radio bearer or for layer 2 and higher layer signaling messages. The multiplexing of these transport channels onto the same or different physical channels is carried out by L1. In addition, the Transport Format Combination Indication (TFCI) field uniquely identifies the transport format used by each transport channel within the current radio frame. MAC multiplexing MAC functions include control of transport format, priority handling between voice/data services of a mobile and priority handling among all mobiles common channel message scheduling, mobile identification. In addition to service multiplexing in physical layer, meaning that different services from an mobile may possibly use one channelization code which is handled by the physical layer (a UMTS/WCDMA feature, different from cdma2000), UMTS MAC also allows for service multiplexing in MAC layer. For example, it allows several upper layer services (RLC instances) to be mapped onto the same transport channel. The MAC layer provides data transfer services on logical channels. A set of logical channel types is defined for different kinds of data transfer services as offered by MAC [7]. A general classification of logical channels is split into two groups: control channels (for the transfer of control plane information) and traffic channels (for the transfer of user plane information). Control channels include Broadcast Control Channel (BCCH, a downlink channel for broadcasting system control information), Paging Control Channel (PCCH, a downlink channel that transfers paging information), Common Control Channel (CCCH, bi-directional channel for transmitting control information between network and mobiles), and Dedicated Control Channel (DCCH, a point-to-point bi-directional channel that transmits dedicated control information between a mobileand the network). There is only one type of traffic channel, Dedicated Traffic Channel (DTCH, a point-to-point channel, dedicated to one mobile, for the transfer of user information. A DTCH can exist in both uplink and downlink). The following mapping between logical channels and transport channels exist: • • • •

BCCH is connected to BCH PCCH is connected to PCH CCCH is connected to RACH and FACH DCCH and DTCH can be connected to either a RACH, a FACH, a DSCH, or to a DCH

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BCCH

PCCH

BCH

PCH

CCCH

RACH

DCCH

FACH

DSCH

DTCH

DCH

Fig 2 Mapping between logical channel and transport channel

Figure 2 shows the mapping relation between logical channel and transport channel. It should be noted that RRC allocates radio resources on a slow basis. It decides and assigns transport format for service bearer possibly in a service life cycle to meet individual user s QoS requirement. The MAC controls radio resource on a fast basis, in the sense that, given the transport format combination set assigned by RRC, MAC selects the appropriate transport format within an assigned transport format set for each active transport channel depending on source rate and total interference threshold level. RLC Protocol RLC is responsible for the efficient transmission or retransmission under variable bit rate. Therefore, a minimal segmentation overhead, a simple retransmission protocol, and an optimized transmission or retransmission unit size, are necessary for RLC design in different radio environment (e.g., different fading scenario). RLC protocol should be configurable by layer 3 to provide different levels of QoS. This is controlled by adjusting the maximum number of retransmissions according to service delay requirements. Three types of services are provided by RLC to higher layers. Transparent mode offers service for transmitting higher layer PDUs without adding any protocol information (possibly including segmentation/re-assembly functionality). Unacknowledged mode offers service for transmitting higher layer PDUs without guaranteeing delivery to the peer entity. Acknowledged mode offers service for transmitting higher layer PDUs and guarantees delivery to the peer entity. For this service, both in-sequence and out-of-sequence delivery are supported.

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RLC transparent control SAP mode SAP

unacknowledged mode SAP

acknowledged mode SAP

segmentation /reassembly

segmentation /reassembly

segmentation /reassembly

buffer (transmitter /receiver)

add/remove RLC header

add/remove RLC header

buffer (transmitter /receiver)

retransmission buffer

buffer (transmitter /receiver)

MUX/DEMUX/MAPPING

BCCH

PCCH

CCCH

DCCH

DTCH

Fig 3: RLC protocol model

Figure 3 shows the RLC entities for UTRAN. Three types of Service Access Points (SAPs) are used, transparent mode SAP, unacknowledged mode SAP, and acknowledged mode SAP, corresponding to the services provided by the RLC. RLC control SAP may be used by RRC for requesting status report (e.g., buffer status). Transparent mode entity controls the data flow for BCCH, PCCH, and DTCH logical channels. The entity includes segmentation/re-assembly function and transmitter/receiver buffer. Both unacknowledged mode and acknowledged mode entity include segmentation/reassembly function, RLC header addition/removal function, and transmitter/receiver buffer. In addition, acknowledged mode entity includes retransmission buffer. The retransmission buffer receives acknowledgement form the receiving side. Then, the acknowledgment is used to indicate retransmissions of RLC Protocol Data Units (PDUs) and when to delete a PDU from the retransmission buffer. A number of RLC protocols have been proposed for UMTS [8-10]. A modified SSCOP (Service Specific Connection Oriented Protocol) is one of the candidates [6]. 3G Wireless Technologies By: Josue Valencia December 20, 2000

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MAC Multiplexing for Downlink Shared Channel In UMTS, there is a clear orthogonal channelization code shortage problem on the downlink (there is no such a problem on the uplink, as scrambling code is mobile specific on the uplink, hence each mobile manages a orthogonal channelization code tree). The problem will become worse if each packet data user is allocated with one permanent channelization code. DSCH, allowing multiple mobiles share the same code, is proposed to resolve this problem. The requirement for DSCH are Minimize the impact of L1 configuration. Simplifies orthogonal spreading code allocation. Utilize the existing TFCI definition by maintaining a transport format combination set for all the users using DSCH. User i

User 3

a transport block

a transport block set

U3_TB U3_TB

U3_TB

U3_TB

U2_TB

User 2 U2_TB

U3_T B

U2_TB

U1_TB

User1

U1_TB

U1_TB

U1_TB

U1_TB 10ms

U1_TB 10ms

10ms

U3_TB U3_TB U2_TB

U3_TB U3_TB

U3_TB

U2_TB

U1_TB

U1_TB

U2_TB

U1_TB

U1_TB

U1_TB 10ms (1st)

U1_TB 10ms (2nd)

10ms (3rd)

Fig 4: DSCH time multiplexing

Figure 4 shows a DSCH time multiplexing scheme[11]. The users employing the DSCH transport channel are multiplexed at the MAC layer according to the transport format selected. The multiplexed users (e.g., User 1, User 2, User 3, ) have a common Transport Format Combination set which defines the valid set of transport formats for the DSCH transport channel. With every addition and removal of users using the DSCH Transport Channel, the DSCH combination set is updated. The user-multiplexed transport block set (e.g., in the first 10ms transmission interval time there are two User 1 s transport blocks U1_TB, one User 2 s transport 3G Wireless Technologies By: Josue Valencia December 20, 2000

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block U2_TB, and two User 3 s transport blocks U3_TB) is delivered to the common coding unit in physical layer, which is configured by the information contained in transport format selected via the Transport Format Identifier. A similar process occurs in all the other 10 ms transmission intervals (the second, the third, , and so on). At the mobile MAC sub-layer, the transport block set from each user is de-multiplexed accordingly. From the knowledge of the number of transport blocks and the transport block size from the transport format, the transport block set belonging to the mobile can be extracted. The advantages of the DSCH are clear. Firstly, all mobiles using this transport channel share the same channelisation code. Therefore, downlink channelization code shortage problem is relieved. Secondly, it simplifies channelization code tree management in the downlink (for UMTS, the code tree management is very intensive since it requires managing the code set at every 10 ms for each user). Thirdly, multicast services are supported. Since all users on DSCH use the same code, multicast service is well supported. Fourthly, it is easy to prioritize user data through the selection of transport format by the MAC layer. Lastly, power control can be supported on the DSCH. W-CDMA [12] is based on 5 MHz with a basic chip rate of 4.096 Mchips/s. The frame duration is 10 ms, allowing for low-delay speech and fast control messages. Each radio frame is divided into 16 time-slots of length 0.625 ms, corresponding to one power-control period. On the downlink, layer 2 dedicated data is time-multiplexed with layer 1 control information within each slot. The layer 1 control information contains known pilot bits for uplink closed-loop power control, and a transport format indicator (TFI). The number of bits per downlink slot is not fixed but may vary from 20-1280, corresponding to 32-2048 kbps data rate. cosωt

I DPDCH/ DPCCH

p(t)

Serial

Cch

Cscramble

Parallel

p(t)

Q Cch : channelization code (OVSF) Cscrambling : scrambling code (10 ms) p(t) : root-raised cosine, roll-off 0.22

sinωt

Fig 5: Spreading/Modulation for Downlink Dedicated Physical Channel For the downlink, data modulation is QPSK in which each pair of two bits are serial-to-parallel converted and mapped to the I and Q branch, respectively (Fig. 5). The I and Q branch are then spread to the chip rate with the same channelization code Cch and subsequently scrambled by the same cell specific scrambling code Cscramble. The channelization codes are orthogonal variable spreading factor (OVSF) codes that preserve the orthogonality between downlink channels of different rates and spreading factors. The OVSF codes are defined using a code tree. The down link scrambling code Cscramble is a 40960 chips (10 ms) segment having a length 218 -1 Gold Code [13] repeated in each frame. The total number of available scramble codes is 512, divided into 16 code groups with 32 codes in each group. The grouping of a downlink codes is done to facilitate a fast cell search.

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The parameter k determines the number of bits per Dedicated Physical Data Channel (DPDCH) or Dedicated Physical Control Channel (DPCCH) slot. It is related to spreading factor (SF) of the physical channel as SF = 256 / 2k . The spreading factor may range from 256 down to 4. Note that the DPDCH and DPCCH may be of different rates, having different SFs and thus different values of k. DPDCH and DPCCH are I & Q code multiplexed within each radio frame and transmitted with dual-channel QPSK modulation. Each additional DPDCHs is code multiplexed on either the I- or the Q-branch with this first channel pair. The channelization code for the BCCH is a predefined code that is the same for all cells within the system. The channelization code(s) used for the Secondary Common Control Physical Channel (CCPCH) is broadcasted on the BCCH. The channelization codes for the downlink Dedicated Physical Channels (DPCHs) are decided by network. The mobile is informed about what downlink channelization codes to receive in the downlink Access Grant message that is a base station response to an uplink Random Access request. The set of channelization codes may be changed during the duration of a connection, typically as a result of change in service or inter-cell handoff. A change of downlink channelization codes is negotiated over the DCCH. cos ωt

CD

DPDCH

C scramb

I

C s cramb

Real p(t)

(Optional)

CC

DPCCH

Q *j

p(t) Imag

p(t)

: pulse-shaping filter (root raised cosine, roll-off 0.22)

sin ωt

CD , CC , : channelization codes(OVSF) C scramb

: primary scrambling code (10 ms or 256 chips)

C scramb

: secondary scrambling codes (optional)

Fig. 6: Spreading/Modulation for Uplink Dedicated Physical Channel A downlink scrambling code is assigned to the cell(sector) at initial deployment. The mobile learns about the downlink scrambling code during the cell search process. Each connection is allocated at least one uplink channelization code to be used for the Dedicated Physical Control Channel (DPCCH). In most cases, at least one additional uplink channelization code is allocated for a Dedicated Physical Data Channel (DPDCH). Further uplink channelization codes may be allocated if more than one DPDCH is required. Two types of dedicated physical channels are defined for the uplink: DPDCH and DPCCH. The DPDCH carries layer 2 dedicated data, and DPCCH carries layer 1 control information. Layer 2 and layer 1 data is transmitted in parallel on different physical channel. On the uplink, bits/slot may vary from 10 to 640, corresponding to 16-1024 kbps data rate. As different mobiles use different uplink scrambling codes, the uplink channelization codes may be allocated with no coordination between different connections. The uplink channelization codes are, therefore, always allocated in a predetermined order. The mobile and network only need to agree on the number of uplink channelization codes. The exact codes to be used are then implicitly given. The uplink primary scrambling code is decided by the network. The mobile is 3G Wireless Technologies By: Josue Valencia December 20, 2000

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informed about what primary scrambling code to use in the downlink Access Grant message. The primary scrambling code may, in rare cases, be changed during the duration of a connection. A change of uplink primary scrambling code is negotiated over the DCCH. The secondary uplink scrambling code is optional, typically used in cells without multiuser detection in the base station. The mobile is informed if a secondary scrambling code should be used in the Access Grant message following a random-access request and a handover message. The primary scrambling code is a complex code C scramb = CI + j CQ, where CI and CQ are two different codes from the extended very large Kasami set [13] of length 256. The secondary scrambling code is a 40960 chips (10 ms) segment of length 241 -1 Gold Code. Data modulation is dual-channel QPSK, in which the DPDCH and DPCCH are mapped to the I and Q branches, respectively (Fig 6). The I and Q branch are spread to a chip rate with two different channelization codes CD and CC and subsequently complex scrambled by a mobile specific primary scrambling code C scramb. The scrambled signal may then optionally be further scrambled by a secondary scrambling code C scramb. The primary and secondary CCPCHs are fixed rate downlink physical channels used to carry the BCCH and FACH/PCH, respectively. The CCPCH is modulated and spread in the same way as the downlink dedicated physical channels. In the case of secondary CCPCH, the FACH and PCH are time multiplexed on a frame-by-frame basis within a superframe structure. The set of frames allocated to FACH and PCH, respectively is broadcast on the BCCH. The main difference between CCPCH and a downlink dedicated physical channel is that a CCPCH is not power controlled and is of constant rate. The main difference between the primary and secondary CCPCH is that the primary CCPCH has a fixed predefined rate of 32 kbps, whereas the secondary CCPCH has a constant rate that may be different for different cells, depending on the capacity required for FACH and PCH. A primary CCPCH is continuously transmitted over the entire cell while the secondary CCPCH is only transmitted when there is data available and may be transmitted in a narrow lobe in the same way as a dedicated physical channel. Parallel transport channels (TrCh-1 and TrCh-M) are separately channel-coded and interleaved. The coded transport channels are then time-multiplexed into a coded composite transport channel (CC-Tr_Ch). Interframe (10ms) interleaving is carried out after transport-channel multiplexing. Different coding and interleaving schemes can be applied to a transport channel depending on the specific requirements in terms of error rates, delay, and so forth. This includes the following: • Rate 1/3 convolutional coding is typically applied for low delay services such as voice with -3 moderate error rate requirements (BER ~ 10 ) • A concatenation of rate 1/3 convolutional coding and Reed-Solomon coding plus interleaving -6 can be applied for high-quality service (BER ~ 10 ) Turbo codes are also being considered and will most likely be used for high-rate-quality services. Rate matching is applied to match the bit rate of the CC-Tr-Ch to one of the limited set of bit rates of the uplink or downlink physical channel. Two different rate-matching steps are carried out: 3G Wireless Technologies By: Josue Valencia December 20, 2000

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Static Rate Matching and Dynamic Rate Matching. Static rate matching is carried out with the addition, removal, or redefinition of a transport channel (i.e., on a very slow basis). Static rate matching is applied after channel coding and uses code puncturing to adjust the channel-coding rate of each transport channel so that the maximum bit rate of the CC-Tr-Ch is matched to the bit rate of the physical channel. Static rate matching is applied on both uplink and downlink. Dynamic rate matching is carried out once every 10 ms radio frame (i.e., on a very fast basis). Dynamic rate matching is applied after transport-channel multiplexing and uses symbol repetition so that the instantaneous bit rate of the CC-Tr-Ch is exactly matched to the bit rate of the physical channel. Dynamic rate matching is only applied to the uplink. FCH indicates transmission rate for the current rate on the DPDCH. The coding for the 6 bit FCH is mapped to biorthogonal Walsh functions of length 2 that represent the 64 different values for FCH. The FCH data is interleaved and multiplexed over the entire DPCCH frame. An access attempt corresponds to a random-access burst that consists of two main parts: the preamble part and the message part. The preamble consists of a length-16 complex symbol sequence, the random access signature, spread by cell-specific preamble code of length 256 chips. The message part is divided into a data part and a control part similar to the uplink DPDCH and DPCCH, respectively. The control part consists of known pilot bits for channel estimation and TFI to indicate the bit rate of the data part of the random access burst. The random access burst supports variable-rate random access messages. Between the preamble and message parts there is an idle time period of length 0.25 ms (preliminary value). The idle time period allows for detection of the preamble part and subsequent online processing of the message part..

5.2.1

ARIB WCDMA

Some of key design parameters of ARIB WCDMA are summarized below. Radio Interface Protocol Architecture--Logical channels are used to transmit information (ITUR M.1035). Transport channel is for information transfer. The physical resources are in code, frequency, phase (I/Q) (uplink only) plus time slot (TDD only).

Fig: 7 Radio interface protocol architecture. Dedicated Physical Channel is user dedicated, point-to-point channel. It carries DCH with various bit rate up to 2Mbps. For downlink it is time-multiplexed. The symbol position is optimized for minimizing power control delay. For uplink it is I/Q-multiplexed with DPDCH on I-branch and DPCCH on Q-branch (16kbps). It is continuously transmitted.

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Perch channel is only used in downlink to broadcast over the entire cell. It enables fast cell selection using search code symbols and carries BCH (16ksps). Common Physical Channel For downlink it is shared by multiple mobiles in the same sector. It carries PCH and FACH with 64ksps. For uplink it is shared by multiple mobiles in the same sector and carries RACH with 32kbps or 128kbps. Service Multiplexing--Service specific rate matching is used for multiplexing plural services with different QoS. Same quality outputs are assumed after channel coding and interleaving sharing a common physical channel mapping unit. Forward Link Channel Structure--WCDMA uses time multiplexed pilots (TDM) against code multiplexed pilots (CDM) used by cdma2000 on the forward link. This is one of major differences between W-CDMA and cdma2000. It has been agreed in the standard bodies that the two design concepts have unique advantages. Spreading Codes for Dedicated Channel--Codes have a two-layered structure of spreading codes and scrambling codes. In the downlink, scrambling codes are assigned specifically to each cell, (see Fig. 8), they are assigned specifically to each user on the uplink. Since there are enough scrambling codes, the codes can be assigned to each cell without any constraints. Spreading codes are orthogonal and are used commonly for all cells to minimize the interference between users within the cell. Search codes are optimized for fast cell search. They are 256 chips long and are modulo-2 sum of an Hadamard sequence and a common sequence. Spreading code with Orthogonal Variable Spreading Factor (OSVF) is user-specific. The scrambling code is Gold, cell/sector-specific (10 ms) for downlink and Gold, user-specific 9 (2 *720ms) for uplink. On the downlink OSVF codes enable orthogonality between channels with different spreading factors.

Fig: 8: Two-layered structure of Spreading and Scrambling Codes Fast Cell Search in Intercell Asynchronous System this is an essential concept for WCDMA. It has three stages. On the first search code (common code), it contains slot/symbol timing detection and scrambling code identification.

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Asynchronous Soft Handoff Operation--When in active mode, the mobile continuously searches for new base stations on the current carrier frequency [20]. During the search, the mobile monitors the received signal from neighbouring base stations, compares them to a set of thresholds, and reports them back accordingly to the base station. Based on this information the network informs the mobile station to add or remove base station links from its active set. Power Control Power control is of two types: Signal Interference Ratio (SIR)-based fast closed loop Transmitter Power Control (TPC), and open-loop TPC. The TPC is essential for a CDMA system to solve the near-far problem and to increase the system capacity. W-CDMA uses an adaptive TPC method based on desired signal level or SIR. SIR-based fast closed power control TPC period is 0.625 ms with a delay of a slot of 0.625 ms (minimum). The outer loop adjusts the closed-loop power control target SIR on the basis of the quality information. This function satisfies the required quality (average FER, or average BER) [See Fig. 9 for details}. Open loop power control-- Open-loop TPC is used for channels that cannot use closed-loop TPC. For example, RACH uses open-loop TPC. The receiver estimates the transmission channel s path loss obtained by calculating and averaging the path loss over a sufficient number of fading periods. The transmit power is calculated on the basis of the path loss that is estimated by the receiver of the transmitting cell.

Fig. 9: SIR-based fast closed-loop TPC diagram Variable Rate transmission--Rate matching is possible on a 10 ms frame basis. Rate detection is done either blindly or by using explicit rate information. The downlink is DTX based timemultiplexed while uplink is the repetition based continuous transmission. Muiticode transmission- In the downlink time-multiplexed DPCCH can be shared in multiple dedicated physical channels on one radio link. In the uplink additional DPDCH on either I or Q branch can be shared by a single common DPCCH. 3G Wireless Technologies By: Josue Valencia December 20, 2000

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Packet Data Transmission Packet Data Transmission is flexible with asymmetrical bit rate and very low to very high bit rate. Common channel collisions in random access channel are neglected. For dedicated channel, closed-loop TPC minimizes transmission power depending on traffic characteristics. Infrequent or short packets are used for common channel while frequent or large packets are used for the dedicated channel. Common Architecture for FDD and TDD--Common key parameters include chip rate, frame length, and modulation/demodulation schemes. TDD-specific parts are used only in layer 1 for radio transmission enhancement. Efficient use of total spectrum is achieved by combining the FDD and TDD modes. System-level asymmetry is possible in addition to the link-level asymmetry of W-CDMA. TDD Specific Features —This features include TDMA structure, flexible time-slot allocation for uplink/downlink, optional efficient transmission technologies, fast open power control, downlink transmit diversity, and multiuser detection.

6.

Differences Between W-CDMA and cdma2000

6.1 Capabilities of Physical Layer A comparison shows that the W-CDMA has several attributes similar to the cdma2000. Most of these features are contained in IS-95-A and include: • • • • • • •

Pilot based coherent forward link Orthogonal forward link structure Asynchronous reverse link QPSK modulation Multi-path combining (Using RAKE receivers) Fast closed loop power control Soft/ softer handoff

The main differences between W-CDMA and cdma2000 systems are chip rate, downlink channel structure, and network synchronization [1], [21]. cdma2000 uses a layered structure, similar to W-CDMA. The link layer offers the protocol support and control mechanisms to provide data transport services. It supports varying levels of reliability and QoS characteristics as per the needs of the specific upper layer service. It performs all of the functions that are necessary to map data transport needs of the upper layers into the specific capabilities and characteristics of the physical layer. Link layer maps logical data and signaling channels into code channels that are specifically supported by coding and modulation function of the physical layer. The link layer is subdivided into two sublayers: link access control (LAC), and media access control (MAC). The LAC manages the point to point communication channels between peer upper layer entities Cdma2000 incorporates coherent detection on the uplink to improve its performance compared to non-coherent reception used by IS-95. A pilot signal on the uplink is used to facilitate coherent detection. The cdma2000 uses fast closed loop power control on the downlink-dedicated 3G Wireless Technologies By: Josue Valencia December 20, 2000

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channels with 800 updates per second. The closed loop power control compensates for medium to fast fading and for inaccuracies in open loop power control. Also, fast power control is effective for adaptation of dynamically changing interference conditions due to the activation and deactivation of high power, high data rate users. The power of the uplink channels for a specific user is adjusted at a rate of 800 bits per second. The uplink power control bits are punctured onto a dedicated downlink channel. Additionally, the uplink utilizes turbo codes, which outperform convolutional codes for data rates greater than 9.6 kbps. Since the capacity of a CDMA system is very dependent on the operating Eb/N0 of the receiver, this improvement increases the capacity of the uplink. The cdma2000 system supports 5 and 20 ms frames for control information on the fundamental, and dedicated channels, and uses 20 ms frames for other types of data (including voice). Interleaving and sequence repetition are over the entire frame interval. This provides improved time diversity over systems that use shorter frames. A 20 ms frame is used for voice. A shorter frame would reduce one component of the total voice delay, but degrade the demodulation performance due to the shorter interleaving span. The cdma2000 uses several approaches to match the data rates to the Walsh spreader input rates including adjusting the code rate, using symbol repetition with or without symbol puncturing, and sequence repetition. The cdma2000 with 20 ms frame uses EVRC while the W-CDMA with a 10 ms frame length uses AMR codec. Often 10 ms frame provides less one-way delay than 20 ms frame. However, 20 ms frame yields less overhead, better interleaving performance and time diversity, and also accommodates the EVRC. Cdma2000 uses synchronous base stations, using a GPS for synchronization, whereas W-CDMA uses a asynchronous structure. Synchronous system design enables multi-environment coverage and roaming without additional base station (required for asynchronous systems.) Synchronous cells facilitate more accurate subscriber locations as compared to asynchronous systems. Synchronous systems have potentially shorter hand-off times (they are implementation dependent) than asynchronous systems. The TDD mode of the W-CDMA requires synchronous cells.

6.2 Forward Link Channel Structure the W-CDMA uses time multiplexed pilots (TDM) on the forward link, cdma2000 uses code multiplexed pilots (CDM). This is one of the major differences between the W-CDMA and cdma2000. One of the critical impairments to mobile radio is the frequency-selective Rayleigh fading of the dispersive channel. Several RAKE receivers have been designed to resolve individual components from overall multipath signal. So any multipath component which is 1 chip out of sync with the despreading PN sequences is regarded as approximately equivalent to white noise. Thus this decreases the multipath component s ability to degrade system performance. The frequency-selectivity of the faded signal is removed and diversity combining is made possible. To improve system capacity, it is important to minimize the required Eb/N0 for a given BER. It is well known that coherent detection of BPSK provides 3 dB gain over differential detection in a frequency-non-selective Rayleigh fading environment. (Note in IS-95 differential detection is used in the reverse link and coherent detection is used in the forward link.) The gain can be obtained if the receiver has a prior knowledge of the channel gain and phase. The use of the coherent 3G Wireless Technologies By: Josue Valencia December 20, 2000

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detection with maximum ratio combining, specified in W-CDMA, would provide the optimal performance if perfect channel estimation is possible. For each branch or finger, a channel estimation is required. Two methods of channel phase and gain estimation are available. The first one is the pilot channel-assisted channel estimation or common pilot concept as used in IS-95 and cdma2000. The second one is to interleave a sequence of pilot symbols within the information sequence as used in W-CDMA. This is called the pilot symbol assisted channel estimation. 6.2.1 Comparison of Common Pilot and Individual Pilot Concept Common Pilot Concept with Continuous Channel Estimation In cdma2000, a common pilot using Code Division Multiplexing (CDM) is used in the down link. The common pilot is used both for cell-search and for channel estimation. In this case, a strong pilot signal is broadcast over the entire cell or sector (beam). The pilot channel is used for both channel estimation and power control. Most importantly, the pilots are used for handoff by monitoring the signal Ec/I0 of each cell site or sector. This leads to very accurate (essentially noiseless) estimates of the channel phase. The reason is that the pilot channel power is high and the pilot channel is tracked continuously. This method is called the continuous channel estimation. In IS-95 about 15% to 20% of the total power is used for the pilot channel. As a result of this channel estimation method, even very low power multipath signals are rapidly detected and combined coherently by the RAKE receiver. This leads to only a small loss in performance due to channel estimation relative to the ideal channel estimation. Individual Pilot Concept with Discrete Channel Estimation In the W-CDMA, individual or dedicated pilots with Time Division Multiplexing (TDM) are used for all physical channels in both the up-link and down link. One reason for justifying individual pilots on the down link channel is to support Adaptive Antenna solutions that are expected to increase the capacity and/or coverage of the system. In TDM, moving average or filtering of pilot signal is necessary for channel estimation to increase the signal to noise ratio. In the individual pilot case, pilot symbols are periodically inserted (i.e. time/IQ multiplexed) in the traffic stream of each user. This is referred to as the discrete channel estimation to highlight the fundamental difference due to common pilot concept. The discrete channel estimation is similar to the channel estimation scheme used in GSM. These pilot symbols are used for computing the channel phase and gain as well as the power control commands. In the common pilot case, the channel estimation is essentially noiseless and performed continuously. The channel estimation therefore, is very close to the ideal situation. There appears not much room to improve on it. However, in the individual pilot concept, this is not the case. It is commonly accepted that the individual pilot concept has about 1.1 dB degradation in terms of Eb/N0 for a given BER as compared to the common pilot case. This degradation will reduce the system capacity by 22%. This may also have significant impact on the performance/cost ratio. Two major mechanisms cause this degradation. First the common pilot is strong so the channel gain and phase are more accurately estimated than the individual pilot. Secondly in individual pilot case, the estimated pilot powers used for determining the power control for up/down commands are more noisy than the common pilot. The state-of-art channel estimation algorithms [21-24], are still far from the ideal situation in some environments, [e.g. high velocity (Doppler 3G Wireless Technologies By: Josue Valencia December 20, 2000

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frequency)}. Thus, improving the channel estimation performance is an essential task for the future work. Channel Estimation Algorithms Tracking the rapidly time-varying mobile radio channel is a fundamental issue in wireless communications including TDMA (such as IS-54) and W-CDMA (3G system). In IS-54 for a low symbol rate of 24.3 kbps, the channel impulse response (CIR) can change about 2.6% in amplitude during a symbol period at a Doppler frequency of 100 Hz. In W-CDMA, a method similar to IS-54 is used to estimate the time varying CIR by means of a slot-adaptive strategy based on a signal frame format. This frame format consists of contiguous slots of transmitted data symbols that are interspersed with training through pilot symbols within a long W-CDMA time slot. The time-varying CIR is computed by interpolating a set of estimated CIR values obtained through a periodic training at adjacent data time slots within a W-CDMA time frame [14]. By using the interpolated CIR estimates obtained through pilot symbols, periodically receiver parameters to adapt to the fast fading channel are computed. The key advantage of this strategy is the immunity to decision errors which may likely to occur during a deep fade (e.g., up to 40 dB). The inherent disadvantage is the processing delay and reduction in system capacity. This delay also puts a limitation on the power control delay. This approach of channel estimation is different from some previously investigated block-adaptive schemes like LMS where the equalizer parameters are adapted directly. If solutions are obtained using linear interpolation schemes due to their simplicity and implementation considerations, then there are three algorithms available including Lagrange interpolation, WMSA, and Simple Average. Simple average is the simplest and uses constant equal weights of the pilot blocks. The performance evaluation is not so simple as it is difficult to guarantee that an algorithm is always superior to another for different Doppler frequencies (or vehicle speed), signal to noise ratios Eb/No, etc.. Thus, it is need to study the trade-off for practical considerations.

6.3 Asynchronous Base Station (BS) Mode Two key concepts related to the asynchronous BS Mode [15-17] needs be pointed out. These are Fast Cell Search and Asynchronous Soft-Handoff Operation. Fast Cell Search In order to realize smooth and quick cell acquisition even in an inter-cell synchronous network, a fast cell search function is essential. The specific structure of the perch channel provides this function. Fast cell search is realized by using a common spreading code to detect the slot timing and the scrambling code group identification, so that the search range of scrambling codes can be narrowed down. The first search code is an orthogonal Gold code of length 256chips, transmitted once every slot. The same first search code is used for every cell in the system. The second search code is transmitted in parallel with the first search code. Each second search code uses a code chosen from a set of 17 different Hadamard codes of length 256 chips. This sequence indicates to which among the 32 different code groups, the base station downlink scrambling code belongs. Search code symbols are spread only with orthogonal Gold codes, so that receiver can easily detect them. With the perch channel structure, the speed for cell acquisition by the mobile is significantly accelerated. During the cell search process, the mobile station searches the base station with the lowest path loss. 3G Wireless Technologies By: Josue Valencia December 20, 2000

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Asynchronous Soft Handoff Operation In active mode, the mobile station continuously searches for new base stations on the current carrier frequency [19]. During the search, the mobile station monitors the received signal level from neighboring base stations, compares them to a set of thresholds, and reports them accordingly back to the base station. Based on this information the network informs the mobile station to add or remove base station links from its active set. The active set is defined as the set of base stations from which the same user information is sent, simultaneously demodulated and coherently combined ( i.e. the set of base stations involved in the soft handoff). From the cellsearch procedure, the mobile station knows the frame offset of the primary CCPCH of potential soft-handoff candidates relative to that of the source base station(s) (the base stations currently within the active set). When a soft handoff is to take place, this offset together with the frame offset between the downlink DPCH and the primary CCPCH of the source base station, is used to calculate the required frame offset between the downlink DPCH and the primary CCPCH of the destination base station (the base station to be added to the active set). This offset is selected so that the frame offset between the downlink DPCH of the source and destination base stations at the mobile-station receiver is minimized. Note that the offset between the downlink DPCH and primary CCPCH can only be adjusted in steps of one downlink DPCH symbol to preserve downlink orthogonality. W-CDMA, , supported by ETSI in Europe and ARIB (Association of Radio Industry Businesses) in Japan. has been adopted as a standard by the ITU under the name IMT-2000 direct spread. WCDMA is the air interface technology for the Universal Mobile Telecommunication System (UMTS) 3G standards in the 2GHz bandwidth (the IMT-2000 core band)

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7.

TECHNOLOGY SUMMARIES OF 2G AND 3G SYSTEMS

2G System Designed for

Voice Low bit rate data

Data Services

Up to 64kbps

Technologies

Speech Coding Convolutional Codi Multiple Access (TDMA/CDMA) Low Level Modulat (BPSK, GMSK)

E

O d

i

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8. 2-1/2 SYSTEMS: GPRS, EDGE 8.1

GPRS -General Packet Radio Service

General Packet Radio Service (GPRS) is a packet-linked technology that enables high-speed (115 kilobit per second) wireless Internet and other data communications, using TCP/IP and X.25. Connecting to existing GSM air interface modulation scheme restricts potential for delivering data rates beyond 115 kbps. GPRS represents an enhancement to existing GSM networks that introduces packet data transmission, enabling always on mobility. This means that users can choose to be permanently logged on to e-mail, Internet access and other services, but do not have to pay for these services unless sending or receiving information. GPRS will allow a network to connect with any data source from anywhere in the world, using a GPRS mobile terminal. GPRS will be implemented by adding new packet data nodes and upgrading existing nodes to provide a routing path for packet data between the mobile terminal and a gateway node. The gateway node will provide interworking with external packet data networks for access to the Internet and intranets. The introduction of General Packet Radio Service (GPRS) provides a platform on which to build IMT-2000 frequencies, in the evolution of GSM networks towards 3G capabilities.

8.2

Enhanced Data rates for GSM Evolution (EDGE)

The next key step in the process towards 3G evolution is the implementation of Enhanced Data rates for GSM Evolution (EDGE) [4]. EDGE was developed using HLM schemes in the air interface to enable wireless multimedia IP-based applications at 384 kbps with a bit rate of 48 kbps per time slot, and under good RF conditions, up to 69.2 kbps. These data rates apply only for local area coverage, that is, pedestrian (microcell) and low speed vehicular (macrocell) environments. For high speed vehicular (wide area coverage) environments, the projected data capability is 144 kbps. The IMT-2000 2Mbps requirement for indoor office is met by using a wide band EDGE (1.6 Mhz) carrier. EDGE uses the same TDMA (Time Division Multiple Access) frame structure, logic channel and 200kHz carrier bandwidth as today s GSM networks, using high level modulation (HLM) schemes. EDGE consists of: 200kHz carrier spacing, Quaternary-Offset-QAM (QOQAM) [~16-QAM]; Binary-Offset-QAM (BQAM) [~QPSK]; and GMSK modulation, 8 time-slots per TDMA frame, and a set of convolutional channel codes. The choice of the modulation technique depends upon the data rate. Quaternary Offset Quadrature Amplitude Modulation (Q-O-QAM) has been proposed for EDGE since it can provide higher data rates and good spectral efficiency. An offset modulation scheme is proposed because it offers smaller amplitudevariation than QAM, which can be beneficial when using non-linear amplifiers. EDGE uses the same symbol rate as GSM, pulse shaping similar to GSM, and fits into the GSM spectrum mask. EDGE will co-exist with GSM in the existing 3G Wireless Technologies By: Josue Valencia December 20, 2000

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frequency plan, and provide link adaptation, whereby modulation and coding are adapted for channel conditions.

9. 3G AND MOBILE IP 3G and Mobile Internet services are inextricably linked. Mobile Internet services become far more advanced when 3G technology is deployed, because user data speeds will be so much higher and several different services will be accessible at any one time. Mobile Internet is about far more than Internet access on the move. It represents a whole new way of communicating, with access to personalized services anytime, anywhere. IP is packet-based, which in simple terms, means users can be on line at all times, but without having to pay until data is actually transferred.

10. MARKETING ISSUES There are many critical 3G issues that must be evaluated carefully by service providers in order to make the best decision in migrating their wireless networks to third generation (3G.) Does it make good business sense to migrate to 3G? How much will 3G cost? What market needs does 3G satisfy? Are there alternate ways to satisfy those market needs in a cost-efficient way, using current infrastructure and spectrum in as much as possible? What technology makes the best sense? These are some of the tough questions that need to be evaluated carefully by network operators when planning for a migration towards 3G. It may be that the main driver behind 3G is wireless and mobility applications such as text messaging, wireless modem capabilities, stock trading, check book balancing, location-based information, and others. However, there would be no justification to migrate to 3G in order to deliver these capabilities if the demand for these services is not there. Another important issue is the fact that the US consumer has been conditioned to think that you pay for voice, data is a free add-on. How does the operator entice the consumer to pay for the new data services that can be possible with 3G? One thing to consider is the high cost of spectrum. In Europe, spending in auctions for 3G spectrum has reached absurd levels, says Bruno Lippens, an analyst with Bank Dewaay in Belgium. In Europe, Bids for spectrum have totaled 100 billion euros ($87 billion). Add to that some $250 billion euros to get a network up and running, and you may conclude that 3G, if it s ever going to be profitable, will certainly never be a major profit generator, says Lippens, who estimates break-even points for the various 3G carriers to be five to 10 years away [32]. For equipment providers, the construction of global wireless network offers a tremendous opportunity, as hundreds of billions of dollars of equipment sales are at stake. Current estimates project the worldwide market for 3G terminals will total $1.5 billion in the year 2001, and grow to $9.2 billion in the year 2005. Investment in infrastructure to support 3G services will total $1.3 billion in 2001, and peak in 2003 at at 5.3 billion.

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However, as most service providers are cash-strapped -due in part to the high cost of licenses for spectrum- the only alternative for equipment vendors such as Lucent, Nortel, Ericsson, and others, may be staking billions in loans on the buildout of next-generation wireless networks. However, this is very risky business, as many telecommunications start-ups, and even established ones, have gone belly-up in recent years. In addition, some analysts say any payback on these investments is many years out, and even that return assumes that the ambitious 3G wireless Internet project which promises high-speed Web surfing on handheld phone/computers gets built at all. 3G could end up being the highdefinition TV of wireless, as in always coming next year, says one New York based hedge fund manager. [32].

11. CONCLUSION The explosive growth of mobile wireless usage and the ever-increasing need for high-speed data services, have accelerated the need for the deployment of 3G technologies. 3G systems will offer a plethora of telecommunications services characterized by mobility and advanced multimedia capabilities including voice, low and high-bit-rate data, full-motion video, Internet access and video conferencing. This paper has discussed the key technological aspects of 3G, starting with a brief overview of first generation, second generation, and 2-1/2 G wireless technologies. Mainly, the three main 3G proposals that address IMT-2000 requirements have been discussed in as much detail as possible. This paper also provides information on other topics which are considered relevant to the field of third generation (3G) wireless technologies, and addresses key marketing issues from the point of view of service providers and equipment vendors.

12. ACKNOWLEDGMENTS AND REFERENCES Some of the information presented in this paper was extracted from the Web Pages of Ericsson and Lucent Technologies. Additional technical information was obtained from the following references: 1. 2. 3. 4.

TIA TR45.5, The cdma2000 ITU-R RTT Candidate Submission (0.18), 1998. Dahlman, E., Gudmundson, B., Nilsson, M., and Skold, J., UMTS/IMTS-2000 Based on Wideband CDMA, IEEE Comm., Mag., Vol. 36, No. 9, 48-54, Sept. 1998 Special Issue ITU-2000: Standards Efforts of the ITU, IEEE Personal Comm., Vol. 4, No. 4, August 1997. TR-45 Proposed RTT Submission (UWC-136), TR-45.3/98.03.03.19, March, 1998 3G Wireless Technologies By: Josue Valencia December 20, 2000

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5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23.

24. 25. 26. 27. 28. 29. 30. 31. 32. 33.

Adachi, F., Sawahashi, M., and Suda, H., Wideband DS-CDMA for Next Generation Mobile Communications Systems, IEEE Comm., Mag., Vol. 36, No. 9, 48-54, Sept. 1998 ETSI UMTS YY.02, Layer 1 General Requirements (v.0.4.0) , 1998 ETSI UMTS YY.01, MS-UTRAN Radio Interface Protocol Architecture (v.0.4.1) , 1998 ETSI UMTS L23 S298Y414, Design Criteria on RLC , Nokia, 1998 ETSI UMTS L23 S298Y556, Model of RLC , Ericsson, 1998 ETSI UMTS L23 S298Y499, The Architecture Model of RLC Sub-layer , LGE&ETRI, 1998 ETSI UMTS L23 S298Y320, Downlink Shared Channel Transmission , Lucent Technologies, 1998 ETSI UMTS L23 S298Y397, RLC Additional Functionality Required in SSCOP , Symbionics, 1998 Jabbari, B., and Dinan, E. H., Spreading Codes for Direct Sequence CDMA and Wideband CDMA Cellular Network, IEEE Comm., Mag., Vol. 36, No. 9, 48-54, Sept. 1998 IMT-2000 Workshop, Jersey, Channel Islands, UK, ITU IMT-2000 , Nov. 10-11, 1998 Final IMT-2000 RTT Evaluation Reports, ITU IMT-2000 , September 30, 1998. IMT-2000 RTT Proposals, ITU IMT-2000, June 30, 1998. ARIB, Self Evaluation Report on Japan’s Proposal for Candidate Radio Transmission Technology on IMT-2000 : W-CDMA, September 30, 1998. ETSI, Evaluation Report for ETSI UMTS Terrestrial Radio Access (UTRA) ITU-R RTT Candidate, September 30, 1998. ARIB IMT-2000 Study Committee, Evaluation Methodology for IMT-2000 Radio Transmission Technologies (Version 1), June 19, 1998. France Telecom, On the definition of handover types, ETSI SMG2 UMTS L1 Expert Group#7, Tdoc SMG2 UMTS L1 443/98, Stockholm, Sweden, 14-16 October 1998. Knisely, D., Quinn, L., and Ramesh, N., cdma2000: A Third-Generation Radio Transmission Technology, Bell Labs Technical Journal, Vol. 3, No. 3, 63-78, Jl.-Sept. 1998. Special Issue on Wideband CDMA, IEEE Comm. Mag., Vol. 36, No. 9, September 1998. Fuyun Ling, Optimum reception, performance bound and cut-off rate analysis of reference assisted coherent CDMA communications with applications, IEEE Trans. Comm., revised June 1998, to appear N. Lo D. Falconer, A. Sheikh, Channel interpolation for digital mobile radio communications, Proc. ICC 91, June 1991. Robert C. Qiu, K. Li, I. Cha, WCDMA air interface simulation, 3rd CDMA Int l Conf., Seoul, Korea, Oct. 27-30, 1998. ETSI, Selection procedures for the choice of radio transmission technologies of the UMTS (UMTS 30.03 version 3.2.0), TR 101 112 V3.2.0, April 1998.+ ETSI, Collection of ULTRA system level simulation results, UMTS xx.20 V0.0.1 (1998-08). R. Padovani, Reverse Link Performance of IS-95 Based Cellular Systems , IEEE Personal Communications, vol. 1, pp. 28-34, 1994. Stein Lundby, et. el. Forward Link Simulation Multi-carrier Results for 9600 bps Models and B , TIA TR45.5.4 contribution, 3/30/98. Guidelines for Evaluation of Radio Transmission Technologies for IMT-2000 , ITU-R M.1225. T. Brown & M. Wang, RTT Reverse Link Simulation Result , TIA TR45.5.4 contribution, 2/16/98. Scott Moritz, Investors Fretting Over Nortel’s Wireless Marshall Plan , Internet article Robert C. Qiu, Wen-Yi Kuo and Qiang Cao, W-CDMA and CDMA 2000 for IMT-2000 A Tutorial, May 11, 1999

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13. 3G ACRONYMS 1X From cdma2000 1X (3G1X). First phase of 3G for cdma2000 networks. 1XEV From cdma2000 1X EV (IS-2000 B). One possible evolutionary 3G phase for cdma2000 networks. Divided into two phases: 1XEV-DO (Data Only) and 1XEV-DV (Data and Voice.) 3G Abbreviation for Third Generation - the collective name used to describe mobile systems able to support a wide range of Mobile Internet services, operating with greater bandwidth. 3GPP The Third Party Partnership Project, set up to expedite the development of open, globally-accepted technical specifications for UMTS. 3GPP2 The Third Party Partnership Project set up to expedite the development of open, globally-accepted technical specifications for cdma2000. AAA Authentication, Authorization and Accounting. One of three nodes in the cdma2000 Packet Core Network (PCN.) ALI ATM Line Interface. Interface between ATM and 3G systems. ATM is one of the transport network technologies being used to connect next generation communications networks, where wireline and wireless are integrated. ANSI American National Standards Institute API Application Programming Interface. An open interface that makes it easier for third party developers to create new applications ARIB Association of Radio Industries and Business; the standards-setting body for Japan. ATM Asynchronous Transfer Mode - a type of networking that supports high bandwidth throughput and simultaneous transfer of voice, video and data. AUC/AC Authentication Center - part of the Home Location Register (HLR) in 3G systems, this performs computations to verify and authenticate the user of mobile phones. BLUETOOTH Short-range radio wireless technology, makes it possible to transmit signals over short distances between phones, computers and other devices. BTS / BS Base Transceiver Station / Base Station. The equipment housed in cabinets and co-located with antennas. Cabinets include heating and air-conditioning units, electrical supply, telephony connection and back-up power. CAMEL Customized Application of Mobile Enhance Logic - an ETSI standard for GSM networks that enhances the provision of IN (Intelligent Network) services. CAP CAMEL Application Part 3G Wireless Technologies By: Josue Valencia December 20, 2000

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CDMA Code Division Multiple Access. A technology for digital transmission of radio signals between, for example, a mobile telephone and a radio base station. In CDMA, a frequency is divided using codes, rather than in time or through frequency separation. Implemented in 800 and 1900 MHz systems around the world. cdma2000 cdma2000 is a radio transmission technology and backbone technology for the evolution of cdmaOne/IS-95 to 3G. CDR Call Data Recording - a feature in a telephone system that allows it to collect and record information on incoming and outgoing calls. CORBA Common Object Request Broker Architecture - provides standard object-oriented interfaces between ORBs (Object Request Broker), as well as to external applications and application platforms. EDGE Enhanced Data rates for Global Evolution. EDGE is a technology that gives GSM and TDMA similar capacity to handle pre-3G services. EDGE was developed to enable the transmission of large amounts of data at rates of 384kbit/s. EIR Equipment Identity Register. A database used to verify the validity of equipment being used in mobile networks. It can provide security features such as blocking of calls from stolen mobile phones and preventing unauthorized access to the network. Black-listed equipment prevents call completion. ETSI European Telecommunications Standards Institute - ETSI s purpose is to define standards that will enable the global market for telecommunications to function as a single market. GGSN Gateway GPRS Support Node. One of the two main GPRS nodes, which provides the interface between the radio network and the IP network. GSM Global System for Mobile communication - the largest digital mobile standard in use today. Implemented in 400MHz, 900MHz, 1800MHz and 1900MHz frequency bands. GPRS General Packet Radio Service - an enhancement for GSM and TDMA core networks that introduces packet data transmission. GPRS uses radio spectrum very efficiently and provides users with always on connectivity and high-speed (115 kilobit per second) wireless Internet and data communications. GTP GPRS Tunneling Protocol - creates a secure connection in the IP environment, by encapsulating encrypted data in an IP packet. HA Home Agent. One of three nodes in a cdma2000 Packet Core Network (PCN.) HLR Home Location Register. A permanent database used in mobile systems to identify subscribers and to contain subscriber data related to features and services. IETF Internet Engineering Task Force - one of two technical working bodies of the Internet Activities Board, tasked with developing new TCP/IP standards for the Internet. IMT-2000 3G Wireless Technologies By: Josue Valencia December 20, 2000

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International Mobile Telecommunications-2000. The ITU initiative for standardizing radio access to the global telecommunications infrastructure, through both satellite and terrestrial systems, serving fixed and mobile users in public and private networks - in other words, 3G. IMT-2000 was formerly called FPLMTS, or Future Public Land Mobile Telephony IN Intelligent Network - the capability in a public telecom network that allows new services to be developed quickly and introduced on any scale. IOS Interoperability Standard. The standard used to define open interfaces in cdmaOne and cdma2000 networks IP Internet Protocol — packet data protocol used in the Internet. IS-136 The standard behind TDMA networks Ipv4 Internet Protocol version four - the version of IP most commonly deployed today. Ipv6 Internet Protocol version six - which will, among other things, add significantly to the address capacity, security and real-time capability of IP. IPSec One of the most widely used IP tunneling security protocols. IS-2000 Standard for cdma2000 IS-95 Specification used for air interface of cdmaOne networks ISDN - Integrated Services Digital Network. A digital public telecommunications network in which multiple services (voice, data, images and video) can be provided via standard terminal interfaces. ITU International Telecommunications Union - the part of the United Nations responsible for co-ordinating global telecommunications activities, especially in the area of standards. ITU-R International Telecommunications Union for Radio Standardization Iu UMTS interface between the core network and the RAN (radio access network). IWF Interworking Function for CDMA data using Simple IP. LA Location Area. MAP Mobile Application Part. Part of the SS7 protocol used in GSM. MAP standards address registration of roamers and intersystem hand-off procedures. MGw Media Gateway - a network node that enables a variety of circuit-switched services to interoperate with packet-based IP networks. MPLS Multi Protocol Label Switching. An evolving standard for speeding up IP-based data communications over ATM networks. MSC 3G Wireless Technologies By: Josue Valencia December 20, 2000

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Mobile Switching Center - a switch providing services and co-ordination between mobile users in a moblie network and external networks. O&M Operations & Maintenance. Support for the day to day running of a network. OSA Open System Architecture - enables seamless transfer of information between different systems. OSS Operations Support System. Methods & procedures that directly support the daily operation of a telecoms network. PBN Packet backbone network - the physical network carrying packet data (IP) traffic. PCN Packet Core Network. Packet data network for cdma2000. PCS Personal Communications Services - the collective term for US mobile telephone services in the 1900MHz frequency band. PDC Personal Digital Cellular - a Japanese standard for digital mobile telephony in the 800MHz and 1500MHz bands. PDP Packet Data Protocol - network protocol for handling transfer of packet data. PDSN Packet Data Serving Node. One of three nodes in a cdma2000 PCN. PLMN Public Land Mobile Network. A mobile network established to provide services. QoS Quality of Service. A generic term that in IP networking refers to different levels of prioritization of data packets over a network. RADIUS Remote Authentication Dial In User Service - used in mobile networks to authenticate authorized users. RAN Radio Access Network. The portion of a mobile network that handles subscriber access, including radio base stations and concentration nodes. RNC Radio Network Controller - manages the radio part of the network in UMTS. RTT Radio Transmission Technology SMS Short Message Service mobile-to-mobile text messaging SMS-C Short Message Service Center. Handles management of incoming and outgoing SMS. SGSN Serving GPRS Support Node. The SGSN handles the data traffic of users in a geographical service area and is one of the two types of node implemented in a GPRS environment. TCP/IP Transmission Control Protocol/Internet Protocol. Usually abbreviated to IP, the language 3G Wireless Technologies By: Josue Valencia December 20, 2000

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used by the Internet. TDMA Time Division Multiple Access - a digital radio technique that divides radio spectrum between users using timeslots , rather than (only) frequency separation or codes, used in GSM and TDMA (IS-136) mobile networks. TDMA is also the term used to describe the digital enhancement of the AMPS analog standard, formerly known as D-AMPS (Digital Advanced Multiple Access). TIA Telecommunications Industry Association - a US telecommunications standards body. TMForum The Telecommunicaitons Management Forum - an industry body working to encourage and develop global standards for telecoms management systems. UMTS Universal Mobile Telecommunications System - The name for the third generation mobile telephone standard in Europe, being developed under the auspices of ETSI, and intended mainly for the evolution of GSM networks, within the framework that has been defined by the ITU and known as IMT-2000. UMTS licenses have already been awarded in several European countries UTRA UMTS Terrestrial Radio Access USC User Service Center. UWC: Universal Wireless Communications UWC 136 HS: TDMA-based (North America) proposed 3G system to satisfy the IMT-2000 3G specification VPN Virtual Private Network - a private communications network that uses public network resources, for example to interconnect PBXs and LANs. VoIP Voice over Internet Protocol. A technology for transmitting voice calls over IP-based networks. Also called IP telephony. WAP Wireless Application Protocol - a protocol that enables Internet services to be delivered to small-screen mobile devices. WAP is the first step towards true Mobile Internet WCDMA Wideband Code Division Multiple Access — One of the radio interface technologies that will be used in 3G systems around the world to support multiple high-speed mobile multimedia services such as full-motion video, Internet access and video conferencing. WIN Wireless Intelligent Networking. A TIA standard for ANSI-41 networks that enhances the provision of IN (Intelligent Network) services. VHE Virtual Home Environment. Home Environment (HE) is a term used to describe the service provider (operator or ISP). Virtual Home Environment is a concept for personalized service portability across network boundaries and between terminals. Users are consistently presented with the same personalized features, user interface and services in any network and on any terminal (within the capabilities of the terminal), wherever the user may be located.

3G Wireless Technologies By: Josue Valencia December 20, 2000