5. Wideband CDMA Schemes

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5. Wideband CDMA Schemes

• 5.1 Introduction
• In 1992 World Radio Conference assigned 2GHz
  band to the FPLMTS (Future Public Land Mobile
  Telecommunications Systems)
• FPLMTS is currently known as IMT-2000
• IMT-2000 is commonly known as 3G (third
  generation)
• 3G is to provide enhanced multimedia capability
  to users

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• 5.1.1 Characteristics of 3G Handsets
• a very high bit rate
• enhanced communications
• multimedia enabled
• provide a large colorful screen with touch
  screen facility
• have a built-in video camera
• have the ability to access the Internet
• be lightweight with long battery life

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• 5.3 Characteristics of 3G Systems
• high data rates (minimum) 144 kb/s in all
  radio environments and 2 Mb/s in low-mobility and
  indoor environments
• symmetrical and asymmetrical data transmission
• circuit-switched and packet-switched services,
  such as IP traffic and real-time video
• good voice quality (comparable to wire-line
  quality)
• greater capacity and improved spectrum
  efficiency
• several simultaneous services to end-users and
  terminals, for multimedia services
• the seamless incorporation of 2G cellular
  systems
• global, i.e. international roaming, between
  different IMT-2000 operational environments
• economies of sale and an open global standard

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5.4 ITU Vision of Global Wireless Access in the
21st Century
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5.5 3G Proposals for IMT-2000
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• 5.6 Major 3G Network Proposals
• W-CDMA (Wideband-Code Division Multiple Access)
• - standardizing organization is 3GPP (3G
  Partnership Project)
• UWC-136 (Universal Wireless Communications 136)
• - standardizing organization is 3GPP2 (3G
  Partnership Project 2)
• cdma2000
• - standardizing organization is UWCC (Universal
  Wireless Communications Consortium)

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3GPP Third Generation Partnership Project
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5.7 Roadmap from 2G to 3G
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5.8 Evolution path for GSM IS-136
CTS GSM Cordless Telephone System ASCI
Advanced Speed Call Item CAMEL customized
Application for Mobile Advanced Logic WIN
Wireless Intelligent Network
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5.9 GPP W-CDMA Architecture
RNC - Radio Network Controller RNS - Radio
Network Subsystem SGSN - Serving GPRS Support
Node LCS - Local Services
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5.9.1 Radio Network Controller (RNC) The RNC
controls the radio resources of the Node Bs that
are connected to it. 5.9.2 Radio Network
Subsystems (RNS) Combined, an RNC and the Node B
that are connected to it are know as Radio
Network Subsystem (RNS). 5.9.3 Serving GPRS
Support Node (SGSN) The SGSN includes the Gateway
GPRS Support Node (GGSN) and the Charging Gateway
Function (CGF). The SGSN is analogous to the
Mobile Switching Center (MSC) / Visitor Location
Register (VLR) in the circuit-switched domain.
The SGSN performs the equivalent functions in the
packet-switched domain.
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5.10 Parameters of W-CDMA cdma2000
cdma2000
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Parameters of W-CDMA cdma2000 (continue ...)
cdma2000
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5.11 Parameters of UWC-136
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• 5.12 UMTS (Universal Mobile Telecommunications
  Systems)
• is a part of the ITUs IMT-2000 vision of a
  global family of 3G mobile communications
  systems
• creating the future mass market for high-quality
  wireless multimedia communications
• ETSI selected a new radio interface for UMTS
  called UTRA (UMTS Terrestrial Radio Access) as
  the basis for a global terrestrial radio access
  network

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• Why UMTS?
• enables tomorrows wireless Information Society,
  delivering high-value broadband information,
  commerce and entertainment services to mobile
  users
• speeds convergence between telecommunications,
  IT, media and content industries to deliver new
  services
• will deliver low-cost, high-capacity mobile
  communications up to 2Mbit/sec

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• When UMTS?
• UMTS licenses have already been awarded in
  several European countries
• systems are now in field trial
• How UMTS?
• builds on todays 2G mobile systems
• one of the major new 3G mobile communications
  systems
• will deliver pictures, graphics, video
  communications and other wide-band information

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• 5.13 UMTS Key Technologies
• 5.13.1 UTRA
• combines 2 technologies - W-CDMA for paired
  spectrum bands TD-CDMA for unpaired bands -
  into one common standard
• at least 144 kbps for full mobility applications
  in all environments
• 384 kbps for limited mobility applications in
  the macro micro cellular environments
• 2.048 Mbps for low mobility applications
  particularly in the micro pico cellular
  environments or for short range or packet
  applications in the macro cellular environment

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• 5.13.2 Multi-mode Second Generation/UMTS
  Terminals
• operated with multiple world-wide standards by
  combining UTRA with 2G and other 3G standards
• 5.13.3 Satellite Systems
• provides a global coverage
• using S-band MSS frequency allocations
• services provided are compatible with the
  terrestrial UMTS systems

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• 5.13.4 USIM Cards/Smart Cards
• future smart cards will offer greater memory
  capacity, faster CPU performance, contactless
  operation, high security data storage
• all fixed mobile networks will adopt the same
  lower layer standards to enable USIM roaming on
  all networks
• several applications service providers could
  be accommodated on one card

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• 5.13.5 IP Compatibility
• UMTS will become the most flexible broadband
  access technology which allows for mobile, office
  residential use
• UMTS can support IP non-IP traffic in a
  variety of modes
• 5.13.6 API Application Toolbox
• provides a generic way for applications to
  access terminals networks
• allows the same application to be used on a wide
  variety of terminals
• provides a common method of interfacing
  applications to UMTS networks
• supports security, billing, subscriber
  information, service management, call management,
  SIM management user interaction content
  translation
• built upon Java, WAP, GSM SIM Toolkit Internet
  technologies

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• 5.13.7 Cross Platform Interoperability
• ability to transport multimedia content over
  various types of networks
• 5.13.8 Client-sever Architecture
• UMTS could use client-server applications widely
  deployed in IP world
• 5.13.9 Customer Care Billing Systems
• must be able to effectively operate across all
  the operators in different environments in a
  customer friendly manner
• 5.13.10 Re-configurable Terminals
• radio interfaces will be in a form of toolbox
  whereby the key parameters can be selected to
  adapt to different standards
• downloadable terminals allow operators to
  distribute new communications software over the
  air that is invisible to users

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• 5.13.11 Application Service Download
• capabilities of multimedia terminals can be
  modified over time through software download
• a new UMTS plug-in may come from
  pre-installation on the users terminals,
  download over the air, or supply from on media
  such as CD-ROM
• terminals SIMs will cooperate in requesting,
  storing and executing software plug-ins
• 5.13.12 Smart Antennas
• able to react intelligently to the received
  radio signal, continually modifying their
  parameters to optimize the transmitted received
  signal
• 5.13.13 Broadband Satellite
• future broadband satellite will offer data rates
  in gigabits domain
• some may offer service compatible with UMTS
  service concept using 20/30 GHz range

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5.14 Basic parameters of UTRA FDD/TDD
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5.15 CDMA FDD TDD Schemes
5.15.1 Introduction
In time division duplex (TDD), the uplink and
downlink transmissions are time multiplexed into
the same carrier, in contrast to frequency
division duplex (FDD), where uplink and downlink
transmissions occur in frequency bands separated
by the duplex frequency. Figure 5.15.1
illustrates the principles of TDD and FDD.
Examples of second generation TDD system are
Digital European Cordless Telephone (DECT),
Personal Handy Phone System (PHS), and CT2. These
systems are intended for a low tier radio
environment. Mainly for indoor operation. A
common feature of second generation TDD systems
have not gained as much market support as the
second generation FDD technologies (GSM, IS-95,
PDC and US-TDMA). The main reason for this seems
to be the limited mobility and coverage provided
by TDD systems.
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Downlink
Duplex separation
Uplink
Base Station
FDD
Frequency
Mobile Station
DL Downlink UL Uplink
TDD
Time
Figure 5.15.1
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5.15.2 FDD Versus TDD Systems

• FDD
• Synthesizers on both the transmitter and receiver
  side is required due to simultaneous operation.
• A duplex filter must be applied to prevent TX
  signal leaking to RX side.
• TDD
• The main benefit here is that the terminal is not
  transmitting / receiving simultaneously, and
  hence only one synthesizer and no expensive
  duplex filter is needed.

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5.15.3 WCDMA The WCDMA scheme has been developed
as a joint effort between ETSI and ARIB during
the second half of 1997. 5.15.4 Carrier Spacing
and Deployment Scenarios The carrier spacing has
a raster of 200kHz and can vary from 4.2 to 5.4
MHz. The different carrier spacings can be used
to obtain suitable adjacent channel protections
depending on the interference scenario. Figure
5.15.2 shows an example for the operator
bandwidth of 15 MHz with three cell layers.
Larger carrier spacing can be applied between
operators than within one operators band in
order to avoid inter-operator interference.
Interfrequency measurements and handovers are
supported by WCDMA to utilize several cell layers
and carriers.
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Figure 5.15.2 Frequency utilization with WCDMA
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• 5.15.5 Logical Channel
• WCDMA basically follows the ITU Recommendation
  M.1035 in the definition of logical channels. The
  following logical channels are defined for WCDMA.
  The three available common control channels are
• Broadcast control channel (BCCH) carries system
  and cell specific information
• Paging channel (PCH) for messages to the mobiles
  in the paging area
• Forward access channel (FACH) for messages from
  the base station to the mobile in one cell.
• In addition, there are two dedicated channels
• Dedicated control channel (DCCH) covers two
  channels stand-alone dedicated control channel
  (SDCCH) and control channel (ACCH)
• Dedicated traffic channel (DTCH) for point-to
  associated -point data transmission in the uplink
  and downlink.

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5.15.6 Physical Channels 5.15.6.1 Uplink Physical
Channels There are two dedicated channels and one
common channel on the uplink. User data is
transmitted on the dedicated physical data
channel (DPDCH), and control information is
transmitted on the dedicated physical data
channel (DPDCH). The random access channel is a
common access channel. 5.15.6.2 Downlink
Physical Channels In the downlink, there are
three common physical channels. The primary and
secondary common control physical channels
(CCPCH) carry the downlink common control logical
channels (BCCH, PCH, and FACH) the SCH provides
timing information and is used for handover
measurements by the mobile station.
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5.15.7 Spreading The WCDMA scheme employs long
spreading codes. Different spreading codes are
used for cell separation in the downlink and user
separation in the uplink. In the downlink, Gold
codes of length 218 are used, but they are
truncated to form a cycle of a 10-ms frame. The
total number of scrambling codes is 512, divided
into 32 code groups with 16 codes in each group
to facilitate a fast cell search procedure. In
the uplink, either short or long spreading
(scrambling codes) are used. The short codes are
used to ease the implementation of advanced
multiuser receiver techniques otherwise long
spreading codes can be used. Short codes are
VL-Kasami codes of length 256 and long codes are
Gold sequences of length 241, but the latter are
truncated to form a cycle of a 10-ms frame.
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5.15.8 Handover Base station in WCDMA need not be
synchronized, and therefore, no external source
of synchronization, like GPS, is needed for base
station. Asynchronous base stations must be
considered when designing soft handover
algorithms and when implementing position
location services. Before entering soft handover,
the mobile station measures observed timing
differences of the downlink SCHs from the two
base stations. The mobile station reports the
timing differences back to the serving base
station. The timing of a new downlink soft
handover connection is adjusted with a resolution
of one symbol (i.e., the dedicated downlink
signals from the two base stations are
synchronized with an accuracy of one symbol).
That enables the mobile RAKE receiver to collect
the marco diversity energy from the two base
stations. Timing adjustments of dedicated
downlink channels can be carried out with a
resolution of one symbol without losing
orthogonality of downlink codes.
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5.15.8.1 Interfrequency Handovers Interfrequency
handovers are needed for utilization of
hierarchical cell structures marco, micro, and
indoor cells. Several carriers and interfrequency
handovers may also be used for taking care of
high capacity needs in hot spots. Interfrequency
handovers will be needed also for handovers to
second generation systems, like GSM or IS-95.
5.15.9 Inter-operability Between GSM and
WCDMA The handover between the WCDMA system and
the GSM system, offering world-wide coverage
already today, has been one of the main design
criteria taken into account in the WCDMA frame
timing definition. The GSM compatible multiframe
structure, with the superframe being multiple of
120ms, allows similar timing for inter-system
measurements as in the GSM system itself.
Apparently the needed measurement interval does
not need to be as frequent as for GSM terminal
operating in a GSM system, as inter-system
handover is less critical from intra-system
interference point of view. Rather
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the compatibility in timing is important that
when operating in WCDMA mode, a multimode
terminal is able to catch the desired information
from the synchronization bursts in the
synchronization frame on a GSM carrier with the
aid of frequency correction burst. This way the
relative timing between a GSM and WCDMA carriers
is maintained similar to the timing between two
asynchronous GSM carriers. The timing relation
between WCDMA channels and GSM channels is
indicated in Figure 5.15.3, where the GSM traffic
channel and WCDMA channels use similar 120ms
multiframe structure. The GSM frequency
correction channel (FCCH) and GSM synchronization
channel (SCH) use one slot out of the eight GSM
slots in the indicated frames with the FCCH frame
with one time slot for FCCH always preceding the
SCH frame with one time slot for SCH as indicated
in the Figure 5.15.3.
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GSM FCCH SCH
FCCH (Frequency Correction CH)
SCH (Synchronization CH)
GSM TCH
WCDMA
Figure 5.15.3 Measurement timing relation between
WCDMA and GSM frame structures.
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• 5.16 CDMA2000 Delivering on 3G
• CDMA2000 represents a family of technologies that
  includes CDMA2000 1X and CDMA2000 1xEV.
• CDMA2000 1X can double the voice capacity of
  cdmaOne networks and delivers peak packet data
  speeds of 307 kbps in mobile environments.
• CDMA2000 1xEV includes

• CDMA2000 1xEV-DO (Data Only)

• CDMA2000 1xEV-DO delivers peak data speeds of
  2.4Mbps and supports applications such as MP3
  transfers and video conferencing.

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• CDMA2000 1xEV-DV (Data Voice)

• CDMA2000 1xEV-DV provides integrated voice and
  simultaneous high-speed packet data multimedia
  services at speeds of up to 3.09 Mbps.

• 1xEV-DO and 1xEV-DV are both backward compatible
  with CDMA2000 1X and cdmaOne.

The world's first 3G (CDMA2000 1X) commercial
system was launched by SK Telecom (Korea) in
October 2000. Since then, CDMA2000 1X has been
deployed in Asia, North and South America and
Europe, and the subscriber base is growing at
700,000 subscribers per day. CDMA2000 1xEV-DO was
launched in 2002 by SK Telecom and KT Freetel.
The commercial success of CDMA2000 has made the
IMT-2000 vision a reality.
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5.16.1 Carrier Spacing and Deployment
Scenarios Currently there exist two main
alternatives for the downlink multicarrier and
direct spread options. The multicarrier approach
maintain orthogonality between the cdma2000 and
IS-95 carriers. In the downlink this is more
important because the power control cannot
balance the interfering powers between different
layers, as it can in the uplink. As illustrated
in Figure 5.15.4, transmission on the
multicarrier downlink (nominal 5-MHz band) is
achieved by using three consecutive IS-95B
carriers where each carrier has a chip rate of
1.2288 Mcps. For the direct spread option,
transmission on the downlink is achieved by using
a nominal chip rate of 3.6864 Mcps. The
multicarrier approach has been proposed since it
might provide an easier overlay with the existing
IS-95 systems. This is because without multipath
it retains orthogonality with existing IS-95
carriers. However, in certain conditions the
spectrum efficiency of multicarrier is 5 to 10
worse than direct spread since it can resolve a
smaller number of multipath components.
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Regardless of the downlink solution, if an
operator has a 5-MHz allocation and if at least
1.25 MHz is already in use, the implementation of
either the multicarrier or the direct spread
overlay could be challenging.
1.25 MHz
3.75 MHz
(a)
(b)
Figure 5.15.4 Illustration of (a) multicarrier
and (b) direct spread downlink
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• 5.16.2 Forward Channel
• The forward link for a CDMA2000 channel, whether
  for 1X or 3X implementation, utilizes the
  structure shown in Figure 5.15.5.
• Reviewing the channel structure, the base station
  transmits multiple common channels as well as
  several dedicated channels to the subscribers in
  their coverage area. Each CDMA2000 user is
  assigned a forward traffic channel that consists
  of the following combinations. An important point
  to note is that F-FCHs are used for voice, while
  F-SCHs are for data.
• 1 Forward Fundamental Channel (F-FCH)
• 0-7 Forward Supplemental Code Channels (F-SCHs)
  for both RC1 (Radio Configuration 1) and RC2
• 0-2 Forward Supplemental Code Channels (F-SCHs)
  for both RC3 and RC9

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• The following are some forward channel
  descriptions
• Forward Supplemental Channel (F-SCH)
• Up to two F-SCHs can be assigned to a single
  mobile for high speed data ranging from 9.6 Kbps
  to 153.6 Kbps in release 0 and 307.2 Kbps and
  614.4 Kbps in release A.
• Forward Quick Paging Channel (F-QPCH)
• The quick paging channel enables the mobile
  battery life extension by reducing the amount of
  time the mobile spends parding pages tha tare not
  meant for it.
• Forward Dedicated Control Channel (F-DCCH)
• This replaces the dim and burst and the blank
  and burst. It is used for messaging and control
  for data cells.

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• Forward Transmit Diversity Pilot Channel
  (F-TDPICH)
• This is used to increase RF capacity.
• Forward Common Control Channel
• This is used to send paging data messages, or
  signaling messages.

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• 5.16.3 Reverse Channel
• The reverse link or channel for CDMA2000 has many
  similar properties as the forward link and
  therefore differs significantly from that used in
  IS-95. One of the major difference or rather
  enhancements to CDMA2000 over IS-95 is the
  inclusion of a pilot on the reverse link. The
  structure of the reverse channel for CDMA2000 is
  shown in Figure 5.15.6.
• The following are some of the Reverse Link
  channel descriptions
• Reverse Supplemental Channel (R-SCH)
• When data rates are greater than 9.6 Kbps, a
  R-SCH is required and also a R-FCH is also
  assigned for power control. A total of one or two
  R-SCHs can be assigned per mobile.

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• Reverse Pilot Channel (R-PICH)
• The R-PICH provides pilot and power control
  information. The R-PICH enables the mobile to
  transmit at a lower power level and allows the
  mobile to inform the base station of the forward
  power levels being received, enabling the base
  station to reduce power.
• Reverse Dedicated Control Channel R-DCCH
• This replaces the dim and burst and the blank
  and burst. It is used for messaging and control
  for data calls.
• Reverse Enhanced Access Channel (R-EACH)
• This is meant to minimize the collisions and
  therefore reduce the access channels power.

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5.16.4 Spreading On the downlink, the cell
separation for cdma2000 is performed by two
M-sequences of length 215, one for the I channel
and one for the Q channel, which are phase
shifted by PN-offset for different cells. Thus,
during the cell search process only these
sequences need to be searched. Since there is
only a limited number of PN-offsets, they need to
be planned in order to avoid PN-confusion. In the
uplink, user separation is performed by different
phase shifts of M-sequence of length 241. The
channel separation is performed using variable
spreading factor Walsh sequences, which are
orthogonal to each other. Fundamental and
supplemental channels are transmitted with the
multicode principle. The variable spreading
factor scheme is used for higher data rates in
the supplemental channel. Similar to WCDMA,
complex spreading is used. In the uplink, it is
used with dual-channel modulation.
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5.16.5 Handover It is expected that soft handover
of the fundamental channel will operate similarly
to the soft handover in IS-95. In IS-95, the
active set is the set of base stations
transmitting to the mobile station. For the
supplemental channel, the active set can be a
subset of the Active Set for the fundamental
channel. This has two advantages. First, when
diversity is not needed to counter fading, it is
preferable to transmit from fewer base stations.
This increases the overall downlink capacity. For
stationary conditions, an optimal policy is to
transmit only from one base station the base
station that would radiate the smallest amount of
downlink power. Second, for packet operation, the
control process can also be substantially
simplified if the supplemental channel is not in
soft handover. However, maintaining the
fundamental channel in soft handover provides the
ability to reliably signal the preferred base
station to transmit the supplemental channel when
channel conditions change.
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5.16.6 Commonality Between WCDMA/CDMA2000 Both
WCDMA and CDMA2000 share several commonalties
that are part of the IMT2000 platform
specification. Both systems utilize CDMA
technology and both requires, in their final
version, a total of 5 MHz of spectrum. Both
systems will be able to interoperate with each
other and it is possible for a wireless operator
to deploy both a CDMA2000 network as well as a
WCDMA system, barring, of course, the capital
cost issues. Both systems have a migration path
from existing 2G platforms to that of 3G.
However, the path both systems take is different
and is driven by the imbedded infrastructure the
existing operator has already deployed. Since the
end game is to offer high-speed packet data
services to the end user, the read issue between
both of these standards within the IMT2000
specification is the methodology for how they
realize the desired speed. WCDMA utilizes a wide
band channel, while CDMA2000 utilizes both a
wideband and several narrow band channels in the
process of achieving the required throughput
levels. Additionally, both WCDMA and CDMA2000 are
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• designed to operate in multiple frequency bands.
  Both systems can operate in the same frequency
  bands provided the spectrum is available.
• Therefore, the commonalties between WCDMA and
  CDMA2000 can be summed up in the following brief
  bullet points that were introduced at the
  beginning of this chapter
• Global standard
• Compatibility of service within IMT-2000 and
  other fixed networks
• High quality
• Worldwide common frequency band
• Small terminals for worldwide use
• Worldwide roaming capability
• Multimedia application services and terminals

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1. Multimedia application services and terminals
2. Improved spectrum efficiency
3. Flexibility for evolution to the next generation
   of wireless systems
4. High-speed packet data rates

• 2 Mbps for fixed environment (indoor
  environment)
• 384 Kbps for pedestrian
• 144 Kbps for vehicular traffic

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                     CDMA2000 Subscribe Growth
History January 2001 through October 2002
                                                  
                                                  
                                                  
           
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Reported by the CDMA Development Group October
2002 CDMA Subscriber Growth HistorySeptember
1997 through September 2002