long term evolution (lte) technology
DESCRIPTION
This is presented as a part of fulfilment of M.Tech Seminar at IIT Kharagpur.TRANSCRIPT
Long Term Evolution Long Term Evolution (LTE) Technology(LTE) Technology
Presented by GHANSHYAM MISHRA 11EC63R22M.Tech,RF & Microwave EngineeringIIT KHARAGPUR.
OUTLINE:OUTLINE:Generation of wireless mobile
technologies
Targets for LTE
LTE architecture
LTE enabling technologies: OFDM MIMO antenna technology
Continued….Continued….Spectrum for LTE deployments
Comparative study of 3GPP LTE and Wi-MAX
LTE network performance
LTE- Advanced
References
GENERATION OF GENERATION OF WIRELESS MOBILE WIRELESS MOBILE COMMUNICATION COMMUNICATION
GENERATION FEATURES THROUGHPUT TECHNOLOGY
1 G Analog 14.4 Kbps(peak) AMPS
2 G Digital , Narrowband, Circuit switched data
9.6/14.4 Kbps TDMA(IS-136), GSM, CDMA (IS-95)
2.5 G Packet switched data
171.2 Kbps(peak)20-40 Kbps
GPRS
3 G Digital, broadband and packet data
3.1Mbps(peak)500-700Kbps
CDMA 2000, UMTSEDGE
3.5 G > 2 Mbps Upto 3.6/7.2/14.4 Mbps(peak)1-3 Mbps
HSPA
4 G Digital broadband packet , all IP , very high throughput
100-300Mbps (peak)3.5 Mbps
WIMAX,LTE-A
Beyond 3GBeyond 3GEvolutionary path beyond 3G
◦– Mobile class targets 100 Mbps with high mobility
◦– Local area class targets 1 Gbps with low mobility
3GPP is currently developing evolutionary/ revolutionary systems beyond 3G◦– 3GPP Long Term Evolution (LTE)
IEEE 802.16-based WiMAX is also evolving towards 4G through 802.16m
MOTIVATION FOR 3G MOTIVATION FOR 3G EVOLUTIONEVOLUTION
CURRENT GENERATION SUPER 3G
Voice communication VoIP, high quality video conferencing
SMS, MMS Video messaging
Internet browsing Super-fast internet
Downloadable games Online gaming with mobility
Downloadable video High quality audio & video streaming
No TV service Broadcast TV on-demand
Peer-to-peer messaging Wide-scale distribution of video clips
Mobile payment
File transfer
Many other innovative ideas
LTE TargetsLTE TargetsPeak data rate
– 100 Mbps DL/ 50 Mbps UL within 20 MHz bandwidth.
– Up to 200 active users in a cell (5 MHz)– Less than 5 ms user-plane latency
Mobility– Optimized for 0 ~ 15 km/h.– 15 ~ 120 km/h supported with high
performance.– Supported up to 350 km/h or even up to
500 km/h. Spectrum flexibility: 1.25 ~ 20 MHzReduced capex/opex via simple
architecture
LTE ARCHITECTURELTE ARCHITECTURE Radio Interfaces
Higher Data Throughput Lower Latency More Spectrum Flexibility Improved CAPEX and OPEX
IP Core Network Support of non-3GPP Accesses Packet Only Support Improved Security Greater Device Diversity
Service Layer More IMS Applications (MBMS, PSS, mobile TV now
IMS enabled) Greater session continuity
LTE ARCHITECTURELTE ARCHITECTURE Main logical nodes in EPC are: PDN Gateway (P-GW) Serving Gateway (S-GW) Mobility Management Entity (MME) EPC also includes other nodes and functions, such: Home Subscriber Server (HSS) Policy Control and Charging Rules Function
(PCRF) EPS only provides a bearer path of a certain QoS, control
of multimedia applications is provided by the IP Multimedia Subsystem (IMS), which considered outside of EPS E-UTRAN solely contains the evolved base stations,
called eNodeB or eNB
LTE Enabling LTE Enabling TechnologiesTechnologies
Two main technologies1.Orthogonal Frequency Division
Multiplexing (OFDM)
2.Multiple-Input Multiple-Output (MIMO) Antenna technology
OFDM OFDM We have a high rate (hence, large bandwidth)
stream of modulation symbols Xk (ex. QAM)
Needs to be transmitted on a frequency selective fading channel
Stream Xk is divided into N low rate parallel sub-streams
Bandwidth of each sub-stream is N times narrower
Each sub-stream is carried by one subcarrier
Received must restore each Xk without interference from current or previously transmitted sub-streams
OFDM ConceptOFDM Concept
1
0
1 2exp
N
n kk
knx X
N N
x
+
0je
Ser
ial t
o P
aral
lel
x
x
1je
1Nje
IFFT
Add Guard
guard
X1
XN-1
X1 XN-1
xn
k = 2k/N
TbTg
time
frequencyOFDM Symbol
Ts =Tb+ Tg
01
N-1
Unused subcarriersXk = 0
OFDM Concept:OFDM Concept:OFDM modulation using IFFTGuard time (cyclic prefix) is added
to protect against inter-symbol interference
Guard subcarriers to protect against neighbor channels at both sides
Some subcarriers are used as pilots for channel estimation
After equalization, receiver performs FFT to retrieve back the stream Xk
OFDM ADVANTAGESOFDM ADVANTAGES OFDM is spectrally efficient
IFFT/FFT operation ensures that sub-carriers do not interfere with each other.
OFDM has an inherent robustness against narrowband interference. Narrowband interference will affect at
most a couple of sub channels. Information from the affected sub
channels can be erased and recovered via the forward error
correction (FEC) codes.
Equalization is very simple compared to Single-Carrier systems
OFDM ADVANTAGESOFDM ADVANTAGES
OFDM has excellent robustness in multi-path environments. Cyclic prefix preserves orthogonality between
sub-carriers. Cyclic prefix allows the receiver to capture multi- path energy more efficiently.
Ability to comply with world-wide regulations: Bands and tones can be dynamically turned
on/off to comply with changing regulations.
Coexistence with current and future systems: Bands and tones can be dynamically turned
on/off for enhanced coexistence with the other devices.
MIMOMIMOSignal transmitted from multiple antennas
(Multiple In)Signal received by multiple antennas (Multiple
Out)
• Receiver combines the received signals and optimally combine energy from MxN channels
• Two main types of MIMO Transmit Diversity Spatial Multiplexing
TX RX
M antennas
N antennas
MIMO 2x2, Spatial MIMO 2x2, Spatial MultiplexingMultiplexing
Purpose is to increase data rate (2x2 gives twice data rate) The 4 gains must be known at receiver Spatial multiplexing is a transmission technique in MIMO to transmit
independent and separately encoded data signals from each of the multiple transmit antenna .
1 2 1 3or s g s g
1 1o o or s g s g
Spectrum for LTE Spectrum for LTE deploymentsdeployments An operator may introduce LTE in ‘new’ bands
where it is easier to deploy 10 MHz or 20 MHz carriers.
e.g. 2.6 GHz band(IMT Extension band) or Digital Dividend spectrum700, 800 MHz Or in re-farmed existing mobile bands e.g. 850, 900, 1700, 1800, 1900, 2100 MHz
Eventually LTE may be deployed in all of these bands –and others later
2.6 GHz (for capacity) and 700/800 MHz (wider coverage, improved in-building) is a good combination
LTE offers a choice of carrier bandwidths: 1.4 MHz to 20 MHz; the widest bandwidth will be needed for the highest speeds
Comparative study of Comparative study of 3GPP LTE and Wi-MAX3GPP LTE and Wi-MAX
WiMAX (Worldwide Interoperability for Microwave
Access), is a wireless communication system that can provide broadband access on a large-scale coverage.
It enhances the WLAN (IEEE 802.11) by extending the wireless access to Wide Area Networks and Metropolitan Area Networks.
Parameter WiMAX LTE
Duplex method TDD FDD and TDD
Bandwidth 5 and 10 MHz 1.25, 3, 5, 10, 15 & 20 MHz
Frame size 5 ms 10 ms with 10 sub-frames
Multiplex Access DL OFDMA OFDMA
Multiplex Access UL OFDMA SC-FDMA
Scheduling speed Every frame (5 ms) Every sub-frame (1 ms)
Subcarrier spacing 10.9 kHz 15 kHz
Maximum DL Data rate (SISO)
46 Mbps (10 MHz band) 50 Mbps (10 MHz band)
Modulation QPSK, 16QAM, 64 QAM QPSK, 16QAM, 64 QAM
Diversity MIMO up to 2x2TD & SM
MIMO up to 4x4TD & SM
Advantages/disadvantages for WiMAX and Advantages/disadvantages for WiMAX and LTELTE
Parameter/Criterion WiMAX(+/-) LTE (+/-)
Availability ++ -
Migration costs - ++
Frequency band options + ++
Peak data rates + ++
Adaptive antenna systems + ++
UL performances + ++
DL performances + ++
Mobility + ++
Radio access modes(TDD&FDD)
+ ++
QoS provisioning ++ ++
LTE network deploymentsLTE network deployments
April 7, 2010: The number of mobile operators who have committed to deploy LTE advanced mobile broadband systems has more than doubled in the past year. There are now 64 operators committed to LTE network deployments in 31 countries, according to the Global mobile Suppliers Association (GSA)
LTE commercial networks LTE commercial networks -performance -performance
Signals Research Group conducted the first ever extensive independent drive test evaluation of a commercial LTE network, assessing the performance of the Telia SoneraLTE networks in Stockholm and Oslo, and reported to GSA:
“While still in its infancy, commercial LTE networks in Stockholm and Oslo already outperform many fixed broadband connections, offering average data rates of 16.8Mbps (peak = 50Mbps) and 32.1Mbps (peak = 85Mbps) in 10MHz and 20MHz, respectively. Measured data rates would have been even higher if it had not been for the stringent test methodology, which focused almost entirely on vehicular testing.”
Signals Research Group, LLC “Signals Ahead,” March 2010
LTE: some industry LTE: some industry forecastsforecasts
Maravedis: The number of LTE subscribers worldwide will pass 200 million in 2015
Strategy Analytics: the global LTE handset market will reach 150 million sales units by 2013
ABI Research: by 2013 operators will spend over $8.6 billion on LTE base stations infrastructure
IDC: Spending on LTE equipment will exceed WiMAXequipment spend by end 2011, with worldwide LTE infrastructure revenues approaching USD 8 billion by 2014
Global mobile Suppliers Association (GSA): up to 22 LTE networks are anticipated to be in commercial service by end 2010, and at least 45 by end 2012
Gartner: long Term Evolution will be the dominant next-generation mobile broadband technology
FUTURE OF LTE FUTURE OF LTE LTE-Advanced (LTE-A) LTE-Advanced (LTE-A)
LTE-A shall have same or better performance than LTE
Peak data rate (peak spectrum efficiency)Downlink: 1 Gbps, Uplink: 500 Mbps
Peak spectrum efficiencyDownlink: 30 bps/Hz, Uplink: 15
bps/Hz Same requirements as LTE for mobility,
coverage, synchronization, spectrum flexibility etc
References:References:
[1] Erik Dahlman, Stefan Parkvall, Johan Sköld, Per Beming, "3G Evolution – HSPA and LTE for Mobile Broadband", 2nd edition, Academic Press, 2008, ISBN 978-0-12-374538-5.
[2] K. Fazel and S. Kaiser, Multi-Carrier and Spread Spectrum Systems: From OFDM and MC-CDMA to LTE and WiMAX, 2nd Edition, John Wiley & Sons, 2008, ISBN 978-0-470-99821-2.
[3] H. Ekström, A. Furuskär, J. Karlsson, M. Meyer, S. Parkvall, J. Torsner, and M. Wahlqvist, "Technical Solutions for the 3G Long-Term Evolution," IEEE Commun. Mag., vol. 44, no. 3, March 2006, pp. 38–45.
[4] “The Long Term Evolution of 3G” on Ericsson Review no.2, 2005.
[5] www.3gpp.org