3G LTE & IMT
-Advanced Service
IMT-Advanced
HSN 2006
February 22-24, 2006
Dr. Hyeon Woo Lee
Global Standards & Research
SAMSUNG ELECTRONICS
woojaa@samsung.com
Contents
3G LTE
ƒ Current status
ƒ Air interface technologies (focusing on 3GPP)
ƒ Network architecture technologies (focusing on 3GPP)
IMT-Advanced Service
Samsung Electronics. Co. Ltd.
1/32
Contents
3G LTE
ƒ Current status
ƒ Air interface technologies (focusing on 3GPP)
ƒ Network architecture technologies (focusing on 3GPP)
IMT-Advanced Service
Samsung Electronics. Co. Ltd.
2/32
Mobile Communication Roadmap
Mobility
1995
2000
2005
2010+
4G
3G+
High
Speed
3G
2G
Medium
Speed
( Digital )
1G
( Analog )
Low
Speed
L
( IMT2000 )
AMPS
ETACS
JTACS
NMT
~ 14.4 kbps
A/
CDM
/TD
GSM
MA
2.4 GHz
WLAN
144 kbps
Samsung Electronics. Co. Ltd.
V
O/D
V- D
E
0
A
200 /HSDP
A
M
A
D
M
C
D
W-C
n 3G
TE i
PP/2
WiBro
802.16e
High speed
WLAN
5 GHz
WLAN
/g
1a Wi-Max
1
.
2
80
WPAN
RFID
ZigBee
MANet
802.11b Bluetooth
PAN
384 kbps
<50 Mbps
<100 Mbps
Data
Rates
3/32
3GPP Roadmap
ƒ UTRA-UTRAN Long Term Evolution Study Item (TSG-RAN): Air Interface
ƒ System Architecture Evolution Study Item (TSG-SA): Network Architecture
UTRAN Long-Term
LTE & SAE specifications
- Improved packet service
- Improved coverage
- Reduced latency
Evolution (LTE)
WLAN I/W
Standard
Release
99/4
2000
Workshop
PoC
2001
IMS
MBMS
HSDPA
EDCH
Release 5
2002
(2004.11)
Release 6
2003
2004
2005
Release 7
2006
2007
2008
2009
2010
Release 99/4 system
Commercial
Release 5/6 system
Evolution system
Samsung Electronics. Co. Ltd.
4/32
3GPP Long Term Evolution (LTE)
Evolution target
ƒ
ƒ
ƒ
ƒ
ƒ
Max. data rate: 100 Mbps (downlink), 50 Mbps (uplink) @ 20 MHz
Improved system throughput
Reduced user plane latency: less than 5ms
Reduced control plane latency: less than 100ms
Support of scalable system bandwidth: 1.25/2.5/5/10/15/20 MHz
LTE Schedule
Study Item
Requirement Decision
12
3
2005
Work Item
RAN Architecture,
Multiple access scheme Decision
6
9
RAN-CN functional split Decision
Feasibility
Study
Samsung Electronics. Co. Ltd.
12
Study Item TR Approval
Stage 2 Completion
3
6
2006
9
12
3
2007
6
Channel Structure,
Mobility details Decision
Core
Specification
5/32
3GPP Evolution – Air Interface
Major decisions made in December 2005
ƒ Not support uplink macro diversity combining
ƒ DL OFDMA, UL SC-FDMA
Current status
ƒ Whole LTE concept evaluation to begin from March 2006
ƒ Discussion on UL/DL multiple access details for evaluation
- Channel structure
- Scheduling & link adaptation
- Power control
- Hybrid ARQ
- Interference coordination/mitigation
- Random access procedure
- Cell search
- MIMO, Channel Coding
Samsung Electronics. Co. Ltd.
6/32
3GPP Evolution – Network Architecture
Main objectives
ƒ RAN & CN architecture evolution for new air interface
ƒ Support of heterogeneous access networks
- Mobility between heterogeneous access networks.
Current status
ƒ RAN Architecture
- Ciphering at anchor decided
- Location of ARQ and RRC: either in Node B or Anchor (TBD)
ƒ Interworking with legacy 3G network (under discussion)
- Direct connection with GPRS based 3G PS core; vs
- IP based interworking (independent evolution of access
system)
Samsung Electronics. Co. Ltd.
7/32
3GPP2 Evolution Schedule
Phase 1
Phase 1
Publication
2006
Phase 2 Framework
Decision (2006-6)
Phase 1 Evolution
1. Multi-Carrier EV-DO (CDMA)
2. BW ≤ 20MHz (up to :15FAs)
3. Peak data rate(3Mbps x N)
- FL: 45Mbps / RL: 30Mbps
4. Publication : Feb, 2006
Samsung Electronics. Co. Ltd.
Phase 2
Baseline
Completion
2007
Phase 2
Publication
Phase 2 Evolution
1. OFDM, MIMO, CDMA with FDE
2. BW : ≤ 20MHz (1.25~)
3. Peak data rate (20MHz)
- 100Mbps / 50Mbps
4. Publication : April, 2007
8/32
Framework proposal for Phase 2
1. Lucent-Nortel-Samsung Proposal
• Two modes (loosely and strictly backward compatible)
• FDD (TDD TBD)
2. Nokia Proposal
• Non-backward compatible OFDM FL (no RL details yet)
• FDD
Characteristics
Strictly
Backward
Compatible
(SBC)
Loosely
Backward
Compatible
(LBC)
Co-existing Legacy AT and new AT
FL: OFDMA and CDMA multiplexed in time
slot
RL: CDMA or Hybrid OFDM-CDMA
Legacy AT and new AT in separate carrier
Maximize reuse of existing upper layer
FL: OFDM / RL: OFDM-CDMA
Samsung Electronics. Co. Ltd.
Pros & Cons
- Smooth Migration from legacy system
- Performance loss due to backward
compatibility
- Optimized for broadband system
- Minimum backward compatibility
9/32
Contents
3G LTE
ƒ Current status
ƒ Air interface technologies (focusing on 3GPP)
ƒ Network architecture technologies (focusing on 3GPP)
IMT-Advanced Service
Samsung Electronics. Co. Ltd.
10/32
OFDMA-based Downlink (1)
Benefits
up to 20 MHz
ƒ Improved link performance and spectral efficiency
ƒ Easier to employ spatial multiplexing (MIMO)
ƒ Frequency domain scheduling and link adaptation provides
possibility for improved spectral efficiency
ƒ Improved coverage and spectral efficiency for broadcast services
through straightforward soft radio-link combining
ƒ Fully scalable bandwidth modes to suit varying spectrum
allocations
ƒ Moderate receiver complexity for high bandwidth channel
Drawbacks
ƒ Increased Peak-to-Average Power Ratio (PAPR) Æ not problem
in Node B
Samsung Electronics. Co. Ltd.
11/32
OFDMA-based Downlink (2)
Frame and sub-frame configuration
ƒ Sub-frame duration corresponds to the minimum downlink TTI.
ƒ Concatenation of multiple sub-frames into longer TTIs is FFS
- Improved support for lower data rates and QoS optimization
- Increased complexity
one frame = 10 ms
…
…
20 sub-frames
…
a sub-frame = 0.5ms
Samsung Electronics. Co. Ltd.
7 or 6 OFDM symbols
12/32
OFDMA-based Downlink (3)
Numerology for evaluation
Transmission BW
1.25 MHz
2.5 MHz
5 MHz
10 MHz
Sub-frame duration
0.5 ms
Sub-carrier spacing
15 kHz
1.92 MHz
3.84 MHz
FFT size
128
Number of occupied
sub-carriers†, ††
76
Sampling frequency
(1/2 × 3.84 MHz)
7.68 MHz
23.04 MHz
20 MHz
30.72 MHz
(2 × 3.84 MHz)
(4 × 3.84 MHz)
(6 × 3.84 MHz)
(8 × 3.84 MHz)
256
512
1024
1536
2048
151
301
601
901
1201
Number of OFDM symbols
per sub frame (Short/Long CP)
CP length
15.36 MHz
15 MHz
7/6
Short
(4.69/9) × 6,
(5.21/10) × 1*
(4.69/18) × 6,
(5.21/20) × 1
(4.69/36) × 6,
(5.21/40) × 4
(4.75/72) × 6,
(5.21/80) × 1
(4.73/108) × 6,
(5.21/120) × 1
(4.75/144) × 6,
(5.21/160) ×1
Long
(16.67/32)
(16.67/64)
(16.67/128)
(16.67/256)
(16.67/384)
(16.67/512)
(μs/samples)
†Includes DC sub-carrier which contains no data
†† This is the assumption for the baseline proposal.
Somewhat more carriers may be possible to occupy in case of the wider bandwidth
*: {(x1/y1) x n1, (x2/y2) x n2} means (x1/y1) for n1 OFDM symbols and (x2/y2) for n2 OFDM symbols
Samsung Electronics. Co. Ltd.
13/32
OFDMA-based Downlink (4)
Modulation scheme: QPSK, 16QAM, 64 QAM
Downlink Data multiplexing
ƒ Support both localized (block-wise) and distributed transmission
ƒ Localized transmission
- Beneficial for frequency selective scheduling
ƒ Distributed transmission
- Beneficial for high mobile speed and broadcasting of common
information
Samsung Electronics. Co. Ltd.
14/32
OFDMA-based Downlink (5)
Reference signal (pilot) structure
ƒ Baseline assumption: the second reference symbols always exist
ƒ To be evaluated if the second reference symbols are needed
Frequency domain
0.5 ms
D R1 D
D
D
D
D R1 D
D
D
D
D R1 D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D R2 D
D
D
D
D R2 D
D
D
D
D R2 D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
R1 : First reference symbol
Samsung Electronics. Co. Ltd.
R2 : Second reference symbol
D : Data
15/32
OFDMA-based Downlink (6)
Channel coding and physical channel mapping
ƒ HSDPA interleaver vs. circular buffer (as in cdma2000)
ƒ Chunk-dependent modulation (baseline for evaluation) vs. chunkindependent modulation
Multiple transmit antenna techniques
ƒ MIMO: up to 4 × 4
- Spatial division multiplexing for a single user
- Spatial division multiple access (SDMA) between multiple users
ƒ Open loop transmit diversity
Macro Diversity
ƒ For unicast, the followings are being considered
- Fast cell selection being considered
- Downlink macro diversity for the cells of the same Node B
ƒ Soft combining for multi-cell broadcast signal
- Need sufficient degree of inter-Node-B synchronization, at least
among a sub-set of Node B’s.
Samsung Electronics. Co. Ltd.
16/32
OFDMA-based Downlink (7)
HARQ: IR including Chase combining
Power Control
ƒ Being investigated for physical/L2-control signalling channel, at le
ast for tracking path loss and shadowing
Inter-cell interference mitigation
ƒ Processing/coding gain in combination with cell-specific
scrambling
ƒ Receiver technologies suppressing inter-cell interference
ƒ Inter-cell-interference co-ordination/avoidance
UE measurements
ƒ Channel quality of each resource block
ƒ Adjustable time/frequency granularity of the CQI reporting
ƒ Inter-frequency and inter-RAT handover measurements periods
- To be created by the scheduler (no compressed mode)
Samsung Electronics. Co. Ltd.
17/32
SC-FDMA based Uplink (1)
Single-carrier transmission to reduce the PAPR
Transmitter structure for SC-FDMA
Coded symbol rate= R
DFT
Sub-carrier
Mapping
IFFT
CP
insertion
NTX symbols
Size-NTX
Size-NFFT
Support of both localized and distributed transmission
ƒ Localized transmission for frequency domain scheduling
ƒ Distributed transmission to get frequency diversity gain
Samsung Electronics. Co. Ltd.
18/32
SC-FDMA based Uplink (2)
Sub-frame structure
ƒ Short block for pilot or data symbol and long block for data symbol
ƒ Minimum TTI is equal to the uplink sub-frame duration
- Concatenation of multiple sub-frames into longer uplink TTIs
being considered
1 sub-frame = 0.5 msec
CP
LB#1
CP
SB
CP
#1
LB #2
Samsung Electronics. Co. Ltd.
CP
LB #3
CP
LB #4
CP
LB #5
CP
SB
CP
#2
LB#6
19/32
SC-FDMA based Uplink (3)
Numerology for evaluation
Spectrum
Allocation
(MHz)
Long block size
Sub-frame
Short block size
CP duration
(μs/#of occupied
(μs/#of occupied
Duration
(μs/samples *1)
2
(ms)
subcarriers /samples* ) subcarriers /samples)
20
0.5
66.67/1200/2048
33.33/600/1024
(4.13/127) × 7,
(4.39/135) × 1*
15
0.5
66.67/900/1536
33.33/450/768
(4.12/95) × 7,
(4.47/103) × 1*
10
0.5
66.67/600/1024
33.33/300/512
(4.1/63) × 7,
(4.62/71) × 1*
5
0.5
66.67/300/512
33.33/150/256
(4.04/31) × 7,
(5.08/39) × 1*
2.5
0.5
66.67/150/256
33.33/75/128
(3.91/15) × 7,
(5.99/23) × 1*
1.25
0.5
66.67/75/128
33.33/38/64
(3.65/7) × 7,
(7.81/15) × 1*1
Samsung Electronics. Co. Ltd.
20/32
SC-FDMA based Uplink (4)
Modulation Scheme: QPSK, 16QAM
Uplink reference signal (pilot) structure being considered
ƒ Distributed (left) and localized (right) reference-signal structure
ƒ Reference-signal orthogonality in frequency domain (left) and
“code” domain (right) respectively.
Reference signal #1
Reference signal #2
Reference signal #3
Samsung Electronics. Co. Ltd.
14
14
Short Block 1
Long Block
30
Short Block 2
28
13
28
27
12
26
25
13
12
11
24
23
22
11
10
DC
subcarrier
21
10
9
20
19
9
8
18
17
8
7
16
15
7
6
6
14
13
12
11
9
10
8
5
5
ƒ Frequency-domain staggering of the reference signals of SB2,
relative to SB1
21/32
SC-FDMA based Uplink (5)
Multiplexing of L1/L2 control signaling and data
ƒ TDM is preferred by many companies due to concern on possible PAPR
increase
ƒ FDM to prevent the link budget problem is FFS
Random access procedure
ƒ Timing synchronization
ƒ Network access
SDMA support (e.g. virtual MIMO)
PAPR-reducing modulation
π/4-QPSK
π/2-BPSK
ƒ E.g., π/4-QPSK, π/2-BPSK
Scheduling
Even symbols
Odd symbols
ƒ Scheduling-based transmission for normal data
ƒ Contention-based transmission at least for random access and
scheduling request
Samsung Electronics. Co. Ltd.
22/32
SC-FDMA based Uplink (6)
Power control
ƒ Transmission power control to compensate for at least path loss and
shadowing
ƒ Benefits and possible means for compensating also for fast (multi-path)
fading to be investigated
HARQ
ƒ IR including Chase combining
ƒ Synchronous HARQ assumed, adaptive asynchronous HARQ is FFS
Uplink timing control
ƒ Align uplink transmissions from multiple users within the cyclic prefix
Inter-cell interference mitigation
ƒ Co-ordination/avoidance i.e. by fractional re-use of time/frequency
resources
ƒ Inter-cell-interference randomization via scrambling
ƒ Frequency domain spreading
Samsung Electronics. Co. Ltd.
23/32
Contents
3G LTE
ƒ Current status
ƒ Air interface technologies (focusing on 3GPP)
ƒ Network architecture technologies (focusing on 3GPP)
IMT-Advanced Service
Samsung Electronics. Co. Ltd.
24/32
Enhanced Routing Based on IP Technology
IP based routing enables reduction of RTT delay
Example proposal being discussed
【GTP routing】
GGSN is
needed in any
case.
GTP routing
More suitable
for broadband
and
ubiquitous
packet access
IP routing
GGSN
SGSN
S3G RNC??
AR (Router)
RNC
NodeB
UE
UE
NodeB
UE
NodeB
UE
UE
NodeB
【Optimum routing】
Transmission via
minimum route is
possible.
UE
3G RAN Architecture New RAN Architecture?
Samsung Electronics. Co. Ltd.
25/32
Intelligent Node B with More Functionalities
Having more functionalities in Node B simplifies network
architecture
Example proposal being discussed
ALL IP NW
IP
MAC/RRC
Ethernet
PHY
PHY
Inter-RAT
control
Multi-cell
RRM/RRC
In later stage, some upper
layer functions can be
added to improve system
performance.
Radio
NW
All basic function
for operation
S3G Node B
Samsung Electronics. Co. Ltd.
26/32
Restructuring of Network Elements
User plane and control plane separation
ƒ Optimized routing and handling of user plane and control plane
throughout the system (interfaces, network elements)
ƒ Example proposal being considered
- Keep C-plane functions (e.g. mobility control) in RNC
- “Direct U-plane” between “Intelligent Node B” and SGSN
Convergence of control nodes
ƒ Simplified network architecture helps reduce latency
ƒ Example proposal being considered
- Merge RNC and SGSN into single node
Samsung Electronics. Co. Ltd.
27/32
Contents
3G LTE
ƒ Current status
ƒ Air interface technologies (focusing on 3GPP)
ƒ Network architecture technologies (focusing on 3GPP)
IMT-Advanced Service
Samsung Electronics. Co. Ltd.
28/32
Key features of IMT-Advanced
Key features of IMT-Advanced
ƒ Convergence among other mobile/wireless systems
- Provide seamless connection
- Various Services & QoS satisfying users’ demand
ƒ What is different from 3G
- Data rate: 100Mbps for high mobility, 1Gbps for low mobility
- Provision of Similar degree of QoS to wireline communication
service
- Global Roaming
- Handover between Heterogeneous access networks
- All IP network
Samsung Electronics. Co. Ltd.
29/32
Expected IMT-Advanced Service
TELEMATICS
Ubiquitous
Network
COMMERCE
HEALTH
OFFICE
HOME
Samsung Electronics. Co. Ltd.
30/32
Heterogeneous N/Ws for IMT-Advanced service
Application Server
OPEN API
All IP N/W
Access
Gateway
Soft Switch
Wireline
Nomadic
Mobile
Hot Spot
Sensor N/W
Ad-hoc N/W
3G/ WiBro/4G
Samsung Electronics. Co. Ltd.
MANet
WLAN/ Wi-MAX
31/32
IMT-Advanced architecture
Samsung Electronics. Co. Ltd.
32/32
Thank you !
woojaa@samsung.com