Chapter 1Introduction

1.1 WCDMA in Third-Generation Systems1.2 Spectrum Allocations for Third-Generation Systems1.3 Requirements for Third-Generation Systems1.4 WCDMA and its Evolution1.5 System Evolution

1.1 WCDMA in Third Generation Systems1G systemsanalog cellular systems2G systemsdigital cellular systemsvoice communications, text messaging and internet accesse.g., GSM (Global System for Mobile Communications), PDC (Personal Digital Cellular), cdmaOne (IS-95) and US-TDMA (IS-136)

3G systemsdesigned for multimedia communicationapplicationsperson-to-person communication can be enhanced with high-quality images and videoaccess to information and services on public and private networks will be enhanced by higher data rates and new flexible communication capabilities

WCDMA (Wideband Code Division Multiple Access)emerged as the most widely adopted 3G air interfacespecification has been created in 3GPP (the 3rd Generation Partnership Project), which is the joint standardization project of the standardization bodies from Europe, Japan, Korea, USA and China

Within 3GPPWCDMA is called UTRA (Universal Terrestrial Radio Access) FDD (Frequency Division Duplex) and TDD (Time Division Duplex)the term WCDMA being used to cover both FDD and TDD operationsUTRA is the radio access part of the Universal Mobile Telephone System (UMTS) network

1.2 Spectrum Allocations for Third Generation SystemsWork to develop 3G mobile systems 1992, started with the World Administrative Radio Conference (WARC) of the ITU (International Telecommunications Union)WARC-92 identified the frequencies around 2 GHz that were available for use by future International Mobile Telephony 2000 (IMT-2000) mobile systems, both terrestrial and satelliteWRC-2000World Radiocommunication Conference 2000 (Istanbul, Turkey 8 May-2 June 2000)

WARC-92 IMT-2000 Frequencies

WARC-921920-1980 and 2110-2170 MHz Frequency Division Duplex (FDD, W-CDMA) Paired uplink and downlink, channel spacing is 5 MHz and raster is 200 kHz. An Operator needs 3 - 4 channels (2x15 MHz or 2x20 MHz) to be able to build a high-speed, high-capacity network.1900-1920 and 2010-2025 MHz Time Division Duplex (TDD, TD/CDMA) Unpaired, channel spacing is 5 MHz and raster is 200 kHz. Tx and Rx are not separated in frequency.1980-2010 and 2170-2200 MHz Satellite uplink and downlink.Channel spacing is a term used in radio frequency planning. It describes the frequency difference between adjacent allocations in a frequency plan.Channel raster is 200 kHz, which means that the carrier frequency must be a multiple of 200 kHz.

WRC-2000 IMT-2000 Frequencies

WRC-2000Identified the bands 1710 - 1885 and 2500 - 2690 MHz for IMT-2000Identified those parts of the band 806 - 960 MHz which are allocated to the mobile service on a primary basisAdmitted that High Altitude Platform Stations (HAPS) may use the WARC-92 frequency bands for terrestrial IMT-2000 on restrictive conditions

Decided that the frequency bands 1525 - 1544, 1545 - 1559, 1610 - 1626.5, 1626.5 - 1645.5, 1646.5 - 1660.5 and 2483.5 - 2500 MHz may be used for the satellite component of IMT-2000, as well as the bands 2500 - 2520 MHz and 2670- 2690 MHz, depending on market developmentsDecided that "the bands, or portions of the bands, 1710 - 1885 MHz and 2500 - 2690 MHz, are identified for use by administrations wishing to implement International Mobile Telecommunications-2000 (IMT-2000). This identification does not preclude the use of these bands by any application of the services to which they are allocated and does not establish priority in the Radio Regulations

The WCDMA system is specified in 3GPP for all the following frequency bandsIMT-2000 mobile spectrum around 2 GHz, 800900 MHz and 2.6 GHzfurther frequencies 700 MHz band in USA2.3 GHz (Wireless Communication Services (WCS) band in USApart of the existing broadcast frequencies between 400 and 700 MHz

Frequency Allocation around 2 GHz

Frequency Allocation around 800900 MHz

Frequency Allocation around 2.6 GHz

1.3 Requirements for Third-Generation Systems2G air interfacesGSMIS-95 (the standard for cdmaOne) PDC (Personal Digital Cellular)US-TDMA 2G systems were built mainly to provide speech services in macro cells

New requirements of 3G systemsbit rates up to 2 Mbpsvariable bit rate to offer bandwidth on demandmultiplexing of services with different quality requirements on a single connection, e.g. speech, video and packet datadelay requirementsfrom delay-sensitive real time traffic to flexible best-effort packet data

quality requirementsfrom 10% frame error rateto 10-6 bit error rateco-existence of 2G and 3G systems and inter-system handovers for coverage enhancements and load balancingsupport of asymmetric uplink and downlink traffice.g. web browsing causes more loading to downlink than to uplinkhigh spectrum efficiency

Main differences between WCDMA and GSM networks

Main differences between WCDMA/High Speed Packet Access (HSPA) and GSM/Enhanced Data Rates for GSM Evolution (EDGE) networks, e.g.the larger bandwidth of 5MHz (vs. 200kHz) is needed to support higher bit ratesHSPA Release 7adds a Multiple Input Multiple Output (MIMO) multi-antenna solution higher order modulation 64QAM to support even higher data ratesHSPA pushes more functionalities to the base station and allows flat architecture, which improves the efficiency and the Quality of Service (QoS) capabilities for packet services

Termscarriera carrier wave, or carrier is a waveform (usually sinusoidal) that is modulated (modified) to represent the information to be transmitteddiversitythe property of being made up of two or more different elements, media, or methodsnotein communications, diversity is usually used to provide robustness, reliability, or security

frequency diversitythe process of receiving a radio signal or components of a radio signal on multiple channels (different frequencies) or over a wide radio channel (wide frequency band) to reduce the effects of radio signal distortions (such as signal fading) that occur on one frequency component but do not occur (or not as severe) on another frequency component

Graph of a Waveform and the Distorted Versions of the Same Waveform*

power control WCDMA uses fast closed loop power control in both uplink and downlinkthe downlink fast power control improves link performance and enhances downlink capacity

Close-loop Power Control

WCDMAuplink power controlcell(block)UE1UE2spreading codeUE1cellpath lossUE2BS UE1UE2power controlpowerUE1UE2near-far problem of CDMABS

open-loop power control ()downlink beacon signalpath lossWCDMA uplinkdownlinkuplink/downlinkfast fadingopen-loop power controlUE power setting

downlinkcellUEBSRayleigh fadingBS

Outer Loop Power Control

outer-loop power controltarget SIR setpointradio link connectionuplinkframe error rate (FER)bit error rate (BER)BStarget SIR setpointpower

1.4 WCDMA and its EvolutionEvolutionEuropean research work on WCDMAinitiated in the European Union research projects CODIT (UMTS Code Division Testbed)FRAMES (Future Radio widebAnd Multiple accEss Systems)within large European wireless communications companies, at the start of the 1990s

CODIT and FRAMES projects alsoproduced WCDMA trial systems to evaluate link performancegenerated the basic understanding of WCDMA necessary for standardizationin January 1998 the European standardization body ETSI decided upon WCDMA as the 3G air interfacedetailed standardization work has been carried out as part of the 3GPP standardization process the first full set of specifications was completed at the end of 1999, called Release 99

3GPP specified important evolution steps on top of WCDMARelease 5: High Speed Downlink Packet Access (HSDPA), commercially deployed in 2005Release 6: High Speed Uplink Packet Access (HSUPA), commercially deployed in 2007Release 7: commercially deployed in 2009HSPA evolution is also known as HSPA+

3GPP also specify a new radio system called Long-Term Evolution (LTE), where the target for finalizing 3GPP standardization is during 2007Release-7 and -8 solutions for HSPA evolution will be worked in parallel with LTE development, and some aspects of LTE work are also expected to reflect on HSPA evolution

Standardization and Commercial Operation Schedule for WCDMA and its Evolution

Peak data rate evolution for WCDMAWCDMA Release 99 in theory enabled 2 Mbps, but in practice gave 384 kbpsHSPA in Release 5 and Release 6 pushes the peak rates to 14 Mbps in downlink and 5.7 Mbps in uplinkHSPA evolution in Release 7 brings a maximum 28 Mbps in downlink and 11 Mbps in uplinkLTE will then further push the peak rates beyond 100 Mbps in downlink and 50 Mbps in uplink by using a 20 MHz bandwidth

Peak Data Rate Evolution for WCDMA

1.5 System EvolutionWCDMA is designed for coexistence with GSM, including seamless handovers and dual-mode handsetsMost of WCDMA networks are deployed on top of the existing GSM networkLTE is designed for coexistence with GSM and WCDMA

System Evolution

************Sinusoidal: *Distortion*Beacon:()**