WiBro– A Mobile WiMAX System,and Radio Resource ManagementWiBro– A Mobile WiMAX System,and Radio Resource Management
Byeong Gi LeeSeoul National University
Sept 22, 2006
Technical Presentation at
George Washington University
Seoul National University, BG Lee, Sept. 2006 2
ICT Snapshot - Services ICT Snapshot - Services
Penetration of high-speed Internet (4Q 2005)
0 20 40 60 80
USADenmarkBelgiumJ apanNetherlandCanadaTaiwanKorea
152M
19M
52M
25M 73%
30%
39%
43%
Seoul National University, BG Lee, Sept. 2006 3
31%
18%13%6%
7%
25% NokiaMotorolaSamsungSony EricssonLGOthers
ICT Snapshot - DevicesICT Snapshot - Devices
Mobile phone market share (4Q, 2005)
Seoul National University, BG Lee, Sept. 2006 4
Wireless Internet in Korea 1Wireless Internet in Korea 1
20052001 20082003
Wireless Internet Subscribers
78%
94%
96% 97%
27M
33M
38M 39M
Wireless Internet Subscribers (Source KT)
0
5
10
15
20
25
30
35
40
45
2001 2003 2005 2006.7Mobile Phone Subscribers Wireless Internet Subscribers
Seoul National University, BG Lee, Sept. 2006 5
Wireless Internet in Korea 2Wireless Internet in Korea 2
0.5 billion
20052001
6.7 billion USD
3.7 billion
4.6%
19.8%
35.7%
2008
11.6%
2 billion
2003
Wireless Internet Sales (wrt Total Sales)
Seoul National University, BG Lee, Sept. 2006 6
Part 1. Part 1.
WiBro: A Mobile WiMAX System
Seoul National University, BG Lee, Sept. 2006 7
What is WiBro?What is WiBro?
Harmonization with Mobile WiMAX Based on Harmonization with Mobile WiMAX Based on IEEE 802.16e StandardIEEE 802.16e Standard
- An OFDMA based Profile of IEEE 802.16e Standard- An OFDMA based Profile of IEEE 802.16e Standard
Vehicle speed (60
km/h, 120 km/h)
Good performance
while on the move
MobilityMobility Compatible with
Internet world
Diverse terminal types
(PC/PMP/PDA/Phones etc)
IPIP
1Mbps per user
Broadband
uploading capability
BroadbandBroadband
WiBro (Wireless + Broadband)
Seoul National University, BG Lee, Sept. 2006 8
WiBro on the Evolution Paths to 4GWiBro on the Evolution Paths to 4G
802.11a/g
1995 2000
200 Mbps
~ 14.4 kbps
50 Mbps144 kbps
2010+
384 kbps
2005
2G(Digital)
1G(Analog)
2.4 GHzWLAN802.11b
4G4G
PAN
5 GHzWLAN
3G
(IMT2000)Fast
Slow
1Gbps
OFDMA
CDMA
5 GHzWLAN
802.11n
WiBro
Seoul National University, BG Lee, Sept. 2006 9
WiBro on the Evolution Paths to 4GWiBro on the Evolution Paths to 4G
Harmonization
2000~2002 2003~2004 2005~2006 2008~2010
Cellular Based(3GPP,
3GPP2)
InternetBased(IEEE)
cdma2000 1x
EV-DO
WCDMA
EV-DORev. A
2Mbps/2Mbps
153kbps/2.4Mbps153kbps/307kbps 1.8Mbps/3.1Mbps
2Mbps/14.4Mbps
WCDMA(R6)HSUPA
WCDMA(R5)HSDPA
4G
11Mbps
802.11a/g
54Mbps
802.16a/b/d
75Mbps(Fixed)
WiBro
6Mbps/18.4Mbps
802.16e
11Mbps
802.11b
100Mbps
WiBro-2
30Mbps
EV-DORev. B EV-DO
Rev. C
1.8Mbps/4.9Mbps*3G LTEHSOPA
Seoul National University, BG Lee, Sept. 2006 10
IEEE 802.16 StandardizationIEEE 802.16 Standardization
IEEE 802.16 (~2001) PHY and MAC standard for fixed wireless users with LOS
(10~66GHz)
IEEE 802.16a (~Apr. 2003) For fixed wireless users with NLOS (2~11GHz) Three PHY structures: SC, OFDM, OFDMA
IEEE 802.16c (~Jan. 2003) System profile for interoperability (10~66GHz)
IEEE 802.16d (Rev approval, June 2004) Consolidated standard of .16, .16a, and .16c
IEEE 802.16e (WG ballot, June 2004) 802.16d-based amendment for mobility
Seoul National University, BG Lee, Sept. 2006 11
Standards – 802.16 vs. WiBroStandards – 802.16 vs. WiBro
IEEE 802.16 and WiBro
SCSC OFDMOFDM OFDMAOFDMA
MACMAC
Mobility(Handoff & Sleep mode)
Mobility(Handoff & Sleep mode)
802.16 d
802.16 e
Scalable OFDMA, MIMO, LDPC,
WiBroWiBro
Seoul National University, BG Lee, Sept. 2006 12
WiBro RequirementsWiBro Requirements
Major SystemMajor SystemParametersParameters
Major SystemMajor SystemParametersParameters Radio Access RequirementRadio Access RequirementRadio Access RequirementRadio Access Requirement
TDDTDDTDDTDD Frequency Reuse Frequency Reuse FactorFactor
Frequency Reuse Frequency Reuse FactorFactor
DuplexingDuplexingDuplexingDuplexing1111
OFDMAOFDMAOFDMAOFDMAMultipleMultipleAccessAccess
MultipleMultipleAccessAccess
10 [MHz]10 [MHz]10 [MHz]10 [MHz]ChannelChannel
BWBWChannelChannel
BWBW
MobilityMobilityMobilityMobility≤ ≤ 60 [Km/h]60 [Km/h]≤ ≤ 60 [Km/h]60 [Km/h]
Service CoverageService CoverageService CoverageService Coverage≤≤ 1 [Km]1 [Km]≤≤ 1 [Km]1 [Km]
Spectral Spectral EfficiencyEfficiency
[bps/Hz/cell(sect.)][bps/Hz/cell(sect.)]
Spectral Spectral EfficiencyEfficiency
[bps/Hz/cell(sect.)][bps/Hz/cell(sect.)]Max. DL / UL = 6 / 2Max. DL / UL = 6 / 2
Aver. DL / UL = 2 / 1 Aver. DL / UL = 2 / 1
Max. DL / UL = 6 / 2Max. DL / UL = 6 / 2
Aver. DL / UL = 2 / 1 Aver. DL / UL = 2 / 1
HandoffHandoffHandoffHandoff≤≤ 150 [ms]150 [ms]≤≤ 150 [ms]150 [ms]
ThroughputThroughput(per user)(per user)
ThroughputThroughput(per user)(per user)
Max. DL / UL = 3 / 1 [Mbps]Max. DL / UL = 3 / 1 [Mbps]
Min.DL/UL = 512/128 [Kbps]Min.DL/UL = 512/128 [Kbps]
Max. DL / UL = 3 / 1 [Mbps]Max. DL / UL = 3 / 1 [Mbps]
Min.DL/UL = 512/128 [Kbps]Min.DL/UL = 512/128 [Kbps]
Seoul National University, BG Lee, Sept. 2006 13
Cellular vs. WiBro vs. WLANCellular vs. WiBro vs. WLAN
WiBro
Cellular(2G, 3G)
AP
AP
APAP
Metro Metro ZoneZone
Hot Hot SpoSpo
tt
Indoor
WLAN
Cellular WiBro WLAN
Seoul National University, BG Lee, Sept. 2006 14
WiBro Network ArchitectureWiBro Network Architecture NMS : Network Management System CMS : Contents Management System PMS : Product Management System VCC : Voice Call Continuity MSC : Mobile Switching Center IMS : IP Multimedia Subsystem RAS : Radio Access Station ACR : Access Control Router AAA : Authentication, Authorization and Accounting
RAS ACR
Back End Platform
IMSVCC
Trunk Gatew
ay
BTS MSCBSC
AP
CoreRouter
Edge Router
Edge Router
Internet
Gateway
Core Router
Toll
PSTN
CDMA
WiBro
WiFi
Server Farm(Portal, VOD,
etc)
BillingAAA MediationA
Server
PMS CMS
Seoul National University, BG Lee, Sept. 2006 15
WiBro System by Samsung ElectronicsWiBro System by Samsung Electronics
Access Control Router Radio Access Station
Seoul National University, BG Lee, Sept. 2006 16
WiBro System FunctionsWiBro System Functions
Core Network Traffic Interface
Packet Forwarding
Packet Classification
Packet Header Suppression
Sessio
n C
on
trol
Mob
ilit
y
Man
ag
em
en
t
Secu
rity
M
an
ag
em
en
t
Con
necti
on
Con
trol
Han
doff
Con
trol
(rela
y)
ARQ
MAC PDU Processing Air
Lin
k
Con
trol
MA
C
Sch
ed
ulin
g
Han
doff
Fu
ncti
on
Physical Layer
User Traffic Plane Signaling Plane
MIP
FA
ACR
RAS
Seoul National University, BG Lee, Sept. 2006 17
Deployment of WiBro ServicesDeployment of WiBro Services
Trials (’05~’06)
Commercial services (’06) KT, SKT in Korea
Service trial and commercial service TVA in Brasil
Cooperation in progress with various operators and vendors in Mobile WiMax Forum
Seoul National University, BG Lee, Sept. 2006 18
Commercial WiBro Service by KTCommercial WiBro Service by KT
BunDangArea
22 Radio Access Stations RAS Repeater
Located 20km South of SeoulPopulation: 450,000Area: 70 Km2
Seoul National University, BG Lee, Sept. 2006 19
WiBro PHY - FeaturesWiBro PHY - Features
High spectral efficiency support TDD
Minimize guard band 10MHz BW/OFDMA
Minimize multi-path interference High modulation order (QPSK, 16QAM, 64QAM) &
enhanced channel coding (convolutional turbo code)
Full coverage support Cellular operation with frequency reuse factor 1
High spectral efficiency & easy cell planning Minimize interference using diversity subchannel Compensate low SINR at cell edge using low rate coding
Fast handover with mobile IP
Seoul National University, BG Lee, Sept. 2006 20
WiBro PHY – Features (cont’d)WiBro PHY – Features (cont’d)
Performance enhancement considering mobility H-ARQ
FEC and ARQ Band selection AMC & diversity subchannel
For slowly moving users: allocate band selection AMC subchannels which have high channel quality
For fast moving users: allocate diversity subchannels Support mobility
Short OFDM symbol Pilot structure supporting channel estimation while moving
Support fast access during handover Short frame length Non-contention based control channel access
Seoul National University, BG Lee, Sept. 2006 21
WiBro PHY – Features (cont’d)WiBro PHY – Features (cont’d)
Flexible resource allocation TDD: asymmetric DL / UL allocation Subchannel-level multiuser scheduling
Power saving mechanisms Sleep mode Idle mode
Advanced optional features Smart antenna support Space-time code/Spatial multiplexing support
Seoul National University, BG Lee, Sept. 2006 22
WiBro PHY – OFDMAWiBro PHY – OFDMA
Basic Concept of OFDM Orthogonal Frequency Division Multiplexing : Advanced
FDM Divide into N orthogonal subcarriers Transmit N symbols in N subcarriers respectively Reconstruct N symbols using orthogonality
FDM: Use separated subcarriers (A, C, E) OFDM : Use overlapped orthogonal subcarriers (A,B,C,D,E)
Seoul National University, BG Lee, Sept. 2006 23
WiBro PHY – OFDMA (cont’d)WiBro PHY – OFDMA (cont’d)
One Big Stream Huge bunch of small streams
Long Symbol Period Robust to multipath fading ( Small guard time overhead) Huge bunch + Orthogonality Robust to narrowband
interference Efficient use of radio
spectrum
Appropriate for Broadband System
1Mbps Stream (Ts : 1us)
10 X 100 Kbps (Ts : 10 us)
1us delayed path signal
Narrowband interference
Strong Candidate for the Next-GenerationWireless Access
Seoul National University, BG Lee, Sept. 2006 24
WiBro PHY – System ParametersWiBro PHY – System Parameters
Parameter Value
Duplex TDD
Multiple Access OFDMA
System Bandwidth 10 MHz
Sampling frequency 10 MHz
Number of used tones 864 out of 1,024
Number of data tones 768
Number of pilot tones 96
Tone spacing 9.765625 kHz
Signal bandwidth 8.447 MHz
Ratio of cyclic prefix time to basic OFDM symbol time 1/8
Basic OFDMA symbol time 102.4 s
Cyclic prefix time 12.8 s
OFDMA symbol time 115.2 s
TDD frame length 5 ms
Number of symbols in a frame 42
Seoul National University, BG Lee, Sept. 2006 25
WiBro PHY – Subchannel WiBro PHY – Subchannel
DL-Diversity subchannel (FUSC, full usage) IDcell-based permutation Distributed data subcarriers in a symbol
Seoul National University, BG Lee, Sept. 2006 26
WiBro MAC – FeaturesWiBro MAC – Features
Flexible BW allocation On frame basis
Flexible QoS provisioning UGS, rtPS, nrtPS, BE
Efficient MAC PDU construction Variable size MAC PDU Fragmentation, packing, concatenation
Support header suppression Energy-saving
Sleep & idle mode Handover
Hard & soft handover Multicast and Broadcast Services Security support
Seoul National University, BG Lee, Sept. 2006 27
WiBro MAC – Frame StructureWiBro MAC – Frame Structure
Frame structure Management messages (GMH & CRC) DL-MAP, UL-MAP Burst profile Uplink control channel (CQI, ACK, ranging)
GMH
CRC
DL-MAP IE
DL-MAP IE
DL-MAP IE
GMH
CRC
UL-MAP IE
UL-MAP IE
UL-MAP IE
Burst #1
Burst #2
Burst #3
DL-MAP IE UL-MAP IE
DL-MAP UL-MAP
CQICH
ACK CH
CDMARanging
UL Burst #1
UL Burst #2
UL Burst #3
DOWNLINK UPLINK
Seoul National University, BG Lee, Sept. 2006 28
WiBro Evolution IssuesWiBro Evolution Issues
Scalability 10/20/40MHz TDD, 10/20 MHz FDD
Throughput enhancement MU-MIMO, LDPC
Mobility improvement Up to ~300Km/h
Spectral efficiency increase Up to ~10b/s/Hz/cell
Control overhead minimization Multi-hop relay Backward compatibility
Seoul National University, BG Lee, Sept. 2006 29
Comparison of WiBro, HSPA, and EVDOComparison of WiBro, HSPA, and EVDO
Parameter1xEVDORev A
EVDO Rev B
(3-carrier)
HSDPA HSPA WiBro(2x2)
Duplex FDD FDD FDD FDD TDD
Occupied spectrum 2.5 MHZ 10 MHz 10 MHz 10 MHz 10 MHz
Channel BWDL 1.25 MHZ 5 MHz 5 MHz 5 MHz
10 MHzUL 1.25 MHZ 5 MHz 5 MHz 5 MHz
Peak data rateDL 3.1 Mbps 14.7 MHz 14 Mbps 14 Mbps 46 Mbps
UL 1.8 Mbps 5.4 MHz 2.0 Mbps 5.8 Mbps 14 Mbps
Spectral efficiencyDL 0.85
bps/HZ0.93 bps/Hz 0.78 bps/Hz 0.78 bps/Hz 1.93 bps/Hz
UL 0.36 bps/Hz
0.28 bps/Hz 0.14 bps/Hz 0.30 bps/Hz 0.88 bps/Hz
Net information throughput per channel/sector
DL 1.06 Mbps 4.65 Mbps 3.91 Mbps 3.91 Mbps 14.1 Mbps
UL 0.45 Mbps 1.38 Mbps 0.70 Mbps 1.50 Mbps 2.19 Mbps
Seoul National University, BG Lee, Sept. 2006 30
WiBro ServicesWiBro Services
InternetInternet
• Web Service - E-mail, Internet Browsing
• Information On Demand - Personalized Information Service
• M-Commerce
IP TelephonyIP Telephony
EntertainmentsEntertainments
• AOD/MOD, VOD
• Streaming Broadcasting
• 3D/Interactive Game
• Integrated Messaging Service - SMS/MMS, Group Messaging - Instant Messaging/Chatting
• Mobile Blog - Web Blog + Mobile
• Telematics - Traffic Information, Location Search, etc.
PersonalPersonal
• VoIP, Video Telephony
• PTA - PTT (Push to talk- 1:N telephony)
- PTD (Push to Data - Send data during PTT)
- PTV (Push to Video - 1:N Video telephony)