Transcript 3G / Third generation wireless

3G/Third Generation Wireless
EECS4215 – Mobile Communications
York University
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Outline
• 3G Systems and IMT-2000
• Universal Mobile Telecommunications System
(UMTS)
• Wideband Code Division Multiple Access (WCDMA) Technology
• CDMA2000
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3G Systems and IMT-2000
• Global mobility with a wide range of services:
– Telephony; Messaging; Internet; Data transport
• ITU define the standard for 3G systems:
– International Mobile Telecommunication 2000
• In 1998, the Third Generation Partnership
Project (3GPP) to continue the technical
specification work for a 3G standard.
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UMTS Standardization Process
• In Europe, the European Telecom Standards
Institute (ETSI) was responsible for the UMTS
standardization process.
• Centerpiece of the 3G evolution.
• Using GSM standards for its networks
architecture and wideband CDMA (W-CDMA)
as its air interface technology.
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Data Rates Specified for 3G Services
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2.048 Mbps for picocell applications.
384 Kbps for medium-size cells (micro and macro).
144 and 64 Kbps for large cells (large macro).
14.4 Kbps for continuous low-speed data applications
in very large cells.
• 12.2 Kbps for speech (4.75 – 12.2 Kbps).
• 9.6 Kbps globally (satellite).
New technologies will coexist with previous technology
equipment in base station shelters.
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Universal Mobile Telecommunications
System (UMTS)
• A broadband, packet-based 3G standard.
• Transmission of text, digitized voice, video and
multimedia at data rates of up to 2 Mbps.
• Based on GSM standard.
• Use packet-switched connection using
Internet Protocol (IP).
• Developed mainly for countries with
operational GSM networks.
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Development of UMTS Standard
• The 3GPP wisely kept the core network as close
as the GSM core network specifications.
• Has two types of operations:
– FDD: Different frequencies are used for up and down
links
– TDD: One frequency is used in both up and down links
• TDD has strong advantage over FDD where there
is asymmetry of the up and down links data rates.
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Characteristics of UMTS
• UMTS is superior to 2G technologies because
of following characteristics:
– Higher speech quality
– Supports 2 Mbps data rates
– Also have Virtual Home Environment (VHE): users
are presented with the same personalized
features consistently everywhere
– Improved network security and location based
services.
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Migration Path to 3G/UMTS from 2G Technologies
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UMTS Networks Architecture
• A UMTS network consists of three interacting
domains:
1. The core network (CN)
– switching, routing
– HLR, VLR
– element management system (EMS): manages network
elements such as BS equipment, network radio controllers
(RNCs), the switch, peripherals.
1. The UMTS terrestrial radio access network (UTRAN)
– provides access to network via W-CDMA
1. User equipment (UE) (i.e. mobile phone)
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UMTS Networks Architecture (2)
• UMTS networks operate as an overlay to GSM/EDGE
networks.
• UMTS radio equipment is installed side-by-side with
GSM-based equipment.
• Core network: based on GSM architecture
– uses GPRS/EDGE as the data network foundation
• The base station in UMTS is called Node-B.
• Radio network controller (RNC): control equipment
for Node-Bs (equivalent to BSC in GSM)
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UTMS Network Architecture
The UTMS Network Architecture. Note the separation of the circuit-switched and packet-switched
domains, and how 2G and 3G network elements operate in parallel. Also note how some network
elements are shared in both the 2G and 3G domains.
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Geographic Boundaries in UMTS
• It is important to know users’ approximate
locations
• Division of geographic boundaries in UMTS into
“system areas”, from largest to smallest:
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UMTS systems
Public land mobile network (PLMN)
MSC/VLR or serving GPRS support node (SGSN)
Location area
Routing area (packet-switched domain)
UTRAN registration area (packet-switched domain)
Cell
Subcell
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UMTS QoS Classes
• UMTS services have different quality of service
classes for four types of traffic:
– Conversational class (voice, video telephony and
gaming)
– Streaming class (multimedia, video on demand,
webcast)
– Interactive class (web browsing, network gaming,
database access)
– Background class (email, SMS, downloading)
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The UMTS Core Network
• Based on GSM network technology,
• GPRS/EDGE as the data network foundation
• Provide switching routing for user traffic:
– Circuit-switched (CS) domain
– Packet-switched (PS) domain
• Contains the databases and network
management functions: HLR, VLR, EMS
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The UMTS Core Network (2)
• Voice transmissions are routed to the CS domain.
• Packet-based transmissions are routed to the PS
domain.
• Some of the circuit-switched elements are the MSC,
the VLR and the gateway MSC.
• Elements supporting GPRS/EDGE technology.
• A number portability database (NPDB) is used to
allow users to change network providers while
keeping their phone number.
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UTMS Network Architecture
The UTMS Network Architecture. Note the separation of the circuit-switched and packet-switched
domains, and how 2G and 3G network elements operate in parallel. Also note how some network
elements are shared in both the 2G and 3G domains.
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The UMTS Terrestrial Radio Access
Network (UTRAN)
• RNCs connect
– voice calls to mobile switching centers (MSCs)
– data sessions to packet data service nodes (PDSNs).
• The UTRAN core network is divided into:
– Circuit switched (primary voice) domain
– Packed switched (primary data) domain
• The MTSO connects to the UTRAN system
• The gateway MSC (GMSC) connects to the PSTN
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Functions of the UMTS Base Station
(Node-B)
• Air interface transmission and reception.
• Modulation and demodulation of all
transmissions.
• CDMA physical channel coding.
• Error management.
• Power control.
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Functions of the RNC
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Radio resource control.
Admission control-granting access to the network.
Channel allocation.
Power control settings (imperative to maintain
system capacity).
• Handover (handoff) control and ciphering
(encryption).
• Segmentation and reassembly of packet-based
transmissions.
• Broadcast signaling.
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User Equipment (UE)
• UE: mobile phones, UMTS mobile terminals
• Mobile phones will automatically seek a
UMTS-based frequency/channel first; then
“step down” to GSM if UMTS capacity is not
available.
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Functions of UMTS IC Card
• Same physical characteristics as SIM cards in GSM
• Support of one user service identity module (USIM)
application (optionally more than one).
• Support of one or more user profiles on the SIM
• Update USIM specific information over the air.
• Security functions
• User authentication
• Optional inclusion of payment methods and secure
downloading of new applications
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Wideband Code Division Multiple
Access (W-CDMA) Technology
• W-CDMA has two basic modes of operation:
– FDD: different frequencies are used for up and down
links; used for both voice and data
– TDD: one frequency is used in both up and down links;
for systems with no dual frequency bands
• It’s the radio air interface technology of UMTS.
• First launched in 2001:
– “Narrowband” CDMA uses a 1.25-MHz carrier
– “Wideband” CDMA uses a 5-MHz-wide carrier
• Like CDMA, W-CDMA is a spread-spectrum
modulation technique.
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CDMA2000
• Falls under specification known as IS-2000.
• North American version of W-CDMA.
• 3G CDMA2000 systems deploy more CDMA
carriers per base station:
– Possibly 6 – 8 carriers to accommodate the
additional bandwidth requirements of 3G systems.
• cdmaOne, the CDMA2000 2G predecessor
technology, is still active in today’s network but
likely be sunset by carriers by around 2016.
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CDMA2000 (2)
• Most all CDMA2000 networks were 3G upgrades
from existing cdmaOne networks (IS-95A/B).
• The radio channel bandwidth is the same for
CDMA2000-1x as for existing cdmaOne channels
(a 1.25-MHz carrier), leading to graceful upgrade.
– “1x” means the same bandwidth as cdmaOne
• CDMA2000 1xEV-DO was developed to be
backward compatible with cdmaOne (IS-95A/B).
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CDMA2000-1x (1xRTT) Categories
1. 1xEV (enhanced voice only; first version of 1x).
2. 1xDO (one carrier supporting data services only).
3. 1xDV (one carrier supporting both data and voice
services).
• The 1xRTT platform still uses a 1.25-MHz carrier,
but it uses a different vocoder than legacy
cdmaOne platforms and introduces more Walsh
codes (128 instead of 64):
– The additional Walsh codes support higher data
rates and more voice conversations than was with
cdmaOne platform
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CDMA2000 Network Architecture
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