Comparison of LTE and WiMax

1. LTE and WiMax
Technology and Performance Comparison
Dr.-Ing. Carsten Ball
Nokia Siemens Networks
Radio Access, GERAN &OFDM Systems: RRM and Simulations
EW2007 Panel
Tuesday, 3rd April, 2007
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2. Contents:
• Towards Broadband Wireless Access:
Categorization of different Radio Access Standards
• Radio Access Solutions: the 3GPP and the IEEE Technology Family
• Detailed LTE vs. WiMax Comparison
(Radio Perspective, Focus on lower Layers)
• Performance Numbers: Peak Data Rates, Spectrum Efficiency and
Technology Capability Limits
• LTE or WiMax Market Success, what will be the winning Technology ?
• Operator Use Cases and potential Ways of Acting
• Summary and Conclusions
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3. Towards Broadband Wireless Access
3GPP and IEEE offer a comprehensive migration path to Beyond 3G
WiMAX (IEEE802.16d/e) covers fixed wireless and
nomadic access, the e-Standard extends towards
Mobility / Range (limited) mobility.
HSPA Evolution and LTE target at high data rates
combined with high subscriber mobility.
UMTS Systems
(W-CDMA)
beyond 3G
HSPA >2010
GSM
GPRS EDGE HSPA
Evolution
GERAN IEEE
Evolution 802.16e LTE
(= EDGE-II)
DECT WLAN IEEE
(IEEE 802.11x)
802.16d User
BlueTooth XDSL, CATV, Fiber data rate
0.1 1 10 100 1000 Mbps
Both WiMax and LTE offer excellent User Data Rates in the order of 10 – 160 Mbps (Bandwidth !).
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LTE design seems to be superior especially Commercially not Binding <<< and Data Throughput.
>>> concerning Mobility

4. Radio Access Solutions at a Glance
The 3GPP Technology Family
GERAN UTRAN
LTE
(GSM/GPRS/EDGE) (W-CDMA/HSPA)
• Large installed base with excellent • HSPA to apply the full power of W- • 3G evolution towards full
large-area coverage CDMA @ reduced network cost broadband multimedia services
• Quick and cost-effective upgrade • User experience comparable to • Significantly reduced network cost
of existing networks DSL in terms throughput & latency • Flat Architecture, fully IP based
• Near-broadband data services with • High capacity, full mobility, high • Flexible bandwidth and spectrum
EDGE Phase II (up to 1 Mbps) data security and QoS usage
• Seamless 2G/3G handover – • Quick and cost-effective upgrade • Full mobility, security, QoS assets
worldwide coverage, global of existing networks
roaming • Seamless 2G/3G/LTE handover
• Seamless 2G/3G handover
Full mobility with High speed data rates Broadband multimedia
medium data rates with full mobility at lowest cost
4
Clear 3GPP Evolutionreserved. towards LTE, comprehensive 2G/3G/4G interworking, easy upgrade &
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Path
re-farming potential, seamless services (handover, roaming), full high-speed mobility.
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5. Radio Access Solutions at a Glance
The IEEE Technology Family
WLAN WiMAX stationary WiMAX mobile
(IEEE 802.11) (IEEE 802.16d) (IEEE 802.16e)
• Solution for specific markets • Fixed or mobile network operators • Fixed or mobile network operators
including municipal networks and • Optimized wireless-DSL services • Optimized wireless-DSL services
backhauling in combination with (Voice + data) (Voice + data)
other radio access technologies,
e.g. WiMAX backhaul for WLAN • Support of charging/billing typical • Support of charging/billing typical
or WLAN backhaul for GSM for DSL (e.g. user classes, for DSL (e.g. user classes,
volume/flat-rate packages) volume/flat-rate packages)
• Hotspot business solution to
complement MNO’s offering • High capacity for stationary use • High capacity; Limited mobility
• High capacity for stationary use • Selective QoS • Selective QoS
Large capacity High speed data rates High speed data rates
for metro networks for fixed wireless access with limited mobility
5
Modular stand-alone Standards allowing for easy combinations and
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offering high performance.
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6. LTE vs. WiMax Comparison (Radio Perspective)
WiMax 802.16e LTE Comments
Flat, IP based; Very Flat, IP based Both technologies with
Network Architecture significantly reduced number of
BS + ASN GW eNodeB + aGW nodes compared to 2G/3G.
Services Packet Data, VoIP Packet Data, VoIP
Full 3GPP Mobility with
Mobility Mobile IP with targeted Target up to 350 km/h; LTE is fully embedded in the
Mobility < 120 km/h 2G/3G Handover and 3GPP world incl. interRAT HO.
Global Roaming
Scalable OFDMA DL: OFDMA, SC-FDMA reduces PAPR by
Access technology in UL & DL ~5 dB UL improvements !!!
UL: SC-FDMA
1.25, 3.5, 5, 7, 8.75, 10, 1.25, 2.5, 5, 10,
Channel BW 14, 15, 20, 28 MHz 15, 20 MHz
Both very flexible
FFT-Size and 128 – 2048; dF variable; 128- 2048; Large dF required against
Subcarrier Spacing 7- 20 kHz typically 10 kHz fixed dF = 15 kHz Doppler => higher velocity
Flexible 1 / 32, ….,1 / 4; Short (5 µs) or Long CP Multipath Fadingto combat
Both designed
Cyclic Prefix CP typical 1 / 8 (17 µs) in different
Environments
Licensed & unlicensed, Licensed, LTE available at preferred low
Spectrum Frequency Bands Coverage
2.3, 2.5, 3.5 & 5.8 GHz IMT-2000 Bands Advantage
TDD + FDD FDD + TDD TDD requires Synchronization,
Duplex Mode FDD can be asynchronous.
TDD focus FDD focus
Framing, TTI 2, …, 20 ms; fixed 2*0.5 ms slots TTI determines the Latency /
5 ms focus = 1 ms sub-frames PING
Modulation & Coding BPSK, …, 64-QAM; QPSK, …, 64-QAM;
CC + CTC (+BTC+LDPC) CC + CTC
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7. LTE vs. WiMax Comparison (Radio Perspective)
WiMax LTE Comments
BS: 1, 2, 4 ; MS: 1, 2 eNodeB: 1, 2, 4 ; UE: 2 LTE working assumption is 2
MIMO, # Antennas
Closed + open Loop Closed + open Loop DL Antennas per UE
MIMO Modes Diversity + Spatial Multi. Diversity + Spatial Multi.
Chase Comb. + IR; Chase Comb. + IR;
HARQ N=8 stop & wait;
stop & wait UL Sync., DL Async.
Subchannel / Physical 24 x 2 Constellation 12 x 14 Constellation
Resource Block Points in PUSC Mode Points
LTE prefers frequency selective
Adjacent AMC 2x3 or
Localized + Distributed; Packet Scheduling,
Interleaving / Mapping PUSC/FUSC Permutation;
Focus Localized WiMax focuses on interference
Focus Permutation
averaging.
DL Preamble + distributed Distributed Pilots
Pilot Assisted Channel
permuted Pilots depending on #
Estimation (PACE) depending on # Antennas Antennas
Overall Overhead @ VoIP + Data Mixture VoIP + Data Mixture LTE is more efficient, e.g. VoIP
MAC Layer typically ~ 25 % typically ~ 15-20 % optimizations
Flexible FCH + MAP Signaling Channels in LTE provides optimized and
L1/L2 Signalling following the Preamble; max. first 3 Symbols; more efficient L1/L2-Signaling
Sync. by Ranging CH Separate BCH, SCH also utilizing CDM components
Flexible arbitrary Stripe-wise Allocation in LTE with less complex
User Multiplexing
Rectangles in T-F-Domain F-Domain Ressource Signaling
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8. Performance Numbers
Peak Data Rates Peak data rates
> 150
100 Mbps
90 Downlink
Uplink
80
70
60
Mbps 50
40
30
20
10
0
2 x 5 MHz 2 x 5 MHz 1 x 10 MHz 1 x 20 MHz 2 x 10 MHz 2 x 20 MHz
HSPA HSPA WiMAX WiMAX LTE LTE
Release 6 Release 8 802.16e 802.16e Release 8 Release 8
• Rather similar Peak Data Rates for HSPA evolution and WiMAX
• LTE provides outstanding Data Rates beyond 150 Mbps in 2 x 20 MHz Bandwidth
due to less overhead
• WiMAX uses asymmetric 29:18 TDD in 10/20 MHz, whereas HSPA and LTE use FDD
with 2 x 5 and 2 x 10/20 MHz
8 •© Prerequisite:All2x2reserved. with 64-QAM in Downlink
Nokia Siemens Networks. rights MIMO
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9. Performance Numbers
Spectrum Efficiency Benchmarking
2.5
Full Buffer Simulation Results
Downlink
2.0 Uplink
bps/Hz/cell
1.5
1.0
0.5
0.0
HSPA R6 HSPA R6 HSPA R7 WiMAX LTE
(TU channel) (Vehicular A) MIMO + reuse 3
64QAM + (29:18 TDD)
equalizer
• Similar spectral efficiency for HSPA evolution and WiMAX due to similar Feature Set
• LTE is expected to provide higher efficiency than HSPA or WiMAX
• WiMax assumed to be deployed in recommended frequency reuse 1/3,
HSPA is definitely deployed in real reuse 1, whereas LTE utilizes fractional tight
9 reuse due to coordinated interference reduction
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10. Performance Numbers
Mobile Technology Capability Limits
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All radio standards show comparable performance under comparable conditions and similar feature set:
• Laws of physics apply to all of them
• User rates mainly depend on bandwidth, modulation/coding and availability of MIMO (2x2 assumed)
• Spectrum Efficiency is determined by Frequency Reuse and Feature Set (e.g. FSPS, MIMO, …)
• Latency (e.g. PING Performance) depends on chosen Frame Duration or TTI
• Coverage depends on frequency band, RF power limitations and duplex mode
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11. LTE or WiMax Market Success, what will be the winning Technology ?
Choosing the right technology path depends on each
operator’s individual situation
E.g.
Available spectrum
Spectrum cost
Regulatory
Standards compliance
constraints
E.g.
Service
s
te
offering
La
ra
te
Competitive
ta
nc
E.g.
Da
situation
y
Population density Technological Legacy
Traffic distribution constraints networks
Demand for Investment
services
Ca
y Protection
Spending on Regional
pa
ci bilit Operator Future
communication constraints ty Mo strategy proofness
Availability and Technology
variety of terminals Evolution Path
Site Locations OPEX
Terminal Costs
Technical characteristics are just one part of the story !!!
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12. LTE or WiMax Market Success, what will be the winning Technology ?
Looking at typical operator use cases, there are most
applicable and probable ways of acting
• Extend 3G to HSPA
Mobile Network Operator
Incumbent 2G/3G
• Extend 2G to EDGE and EDGE II
mobile operator
• Upgrade to LTE later
New 3G • Build up UMTS/HSPA network
mobile operator • Upgrade to LTE later
• Extend to EDGE and EDGE II for mobile data
Incumbent 2G mobile operator • In addition, use WiMAX mostly in urban-area
with BWA (non-3G) license hot-zones, with focus on fixed-line substitution
(voice & data) since HSPA not possible.
Access Provider,
Fixed Networks
New operator • Use WiMAX for licensed bands,
3.5 GHz FDD (fixed/nomadic)
with BWA (non-3G) license or 2.5 GHz TDD (fixed/nomadic/mobile)
No license available • Use WLAN for hotspot/metro networks
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13. Summary and Conclusions:
LTE WiMAX Mobile
IMT2000 WiMax IMT-2000 member
Spectrum other (2.3, 2.5 & 3.5 GHz)
Circuit Switched, Voice (VoIP) (VoIP)
Services Packet Switched, Data
Full Mobility
Mobility Nomadic Mobility
Backwards
Compatibility full 3GPP interoperability
( )
Roaming WiMax to WiMax
Coverage
(LTE-900) , if f < 3.5GHz
Performance Capacity ( )
Latency ( )
Availability 2009/2010 2007/2008
• LTE comes ~ 2 years later than WiMax and hence provides some technical advantages over WiMax.
• LTE must be seen especially in the context of the mature and world-wide dominating GERAN and
UMTS/HSPA Systems allowing for Handover/Roaming as well as Refarming Scenarios.
• Judgment on the “best” technology, however, depends on specific operator needs and prerequisites.
• LTE and WiMax are basically for different customers in different spectrum: no strong Competition.
•13
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© Siemens Networks is pleased to offer a strong and comprehensive Portfolio including
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both WiMax and LTE operating even on the same Platform (NSN FlexiBTS).

14. Thank You …
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15. Dr.-Ing. Carsten Ball
Dr. Carsten Ball received the Dipl.-Ing. degree in electrodynamics in 1993 and the Dr.-Ing.
degree in electrical engineering in 1996 from the Technical University of Karlsruhe, Germany.
Since 1997 he is with Siemens Mobile Networks and since April 2007 with Nokia Siemens
Networks (NSN) in Munich, Germany, currently heading the GERAN and OFDM Systems
Architecture Radio & Simulation group. He is responsible for the GSM, GPRS and EDGE
performance as well as for the upcoming OFDM radio technologies (WiMax, LTE). Dr. Ball’s
research interests include simulation, protocol stacks, optimization and efficient algorithm
design in cellular radio networks.
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16. Backups:
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17. Flat Architecture Evolution
• Flat architecture = single network element in radio network and in the core network
• Significant Node Reduction compared to previous GERAN and UMTS Standard
• Same architecture in i-HSPA, LTE and in WiMAX
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18. Cell Range for Mobile and Fixed Wireless
• Good quality Fixed wireless WiMAX network can be built for outdoor antennas with
GSM/EDGE and UMTS/HSPA sites
• Mobile WiMax suffers from Coverage Challenge (especially indoor) due to high Frequency Bands
• LTE provides comparable coverage to GSM/EDGE (@ 900 MHz) or HSPA (@900/2100 MHz)
Suburban coverage
WiMAX 3500 Uplink
outdoor fixed Downlink
Fixed application
WiMAX 2500 No indoor loss
outdoor fixed
CPE Antenna
WiMAX 3500 indoor height 5 m
mobile
WiMAX 2500 indoor
mobile
Mobile application
HSPA2100 indoor
Indoor loss 15 dB
mobile
MS Antenna
HSPA900 indoor height 1.5 m
mobile
0.0 1.0 2.0 3.0 4.0 5.0
km
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19. Key success factors show clear profiles for
available technologies
Economy of scale Spectrum availability GSM Economy of scale Spectrum availability UTRAN
and cost impact and cost impact
GPRS HSPA
EDGE
IPR regime Variety of terminals IPR regime Variety of terminals
Compatibility with Compatibility with
Voice performance Voice performance
existing standards existing standards
Lean architecture Broadband data performance Lean architecture Broadband data performance
Full mobility with medium data rates High speed data rates with full mobility
Economy of scale Spectrum availability LTE Economy of scale Spectrum availability WiMAX
and cost impact and cost impact
IPR regime Variety of terminals IPR regime Variety of terminals
Compatibility with Compatibility with
Voice performance Voice performance
existing standards existing standards
Lean architecture Broadband data performance Lean architecture Broadband data performance
Broadband multimedia at lowest cost High speed data rates with limited mobility
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20. Technology Choice is Defined by Current Network,
Spectrum Assets and Voice Strategy
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LTE and WiMax are basically for different customers
in different spectrum: no strong Competition expected
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