Transcript Uplink: data coming from Mobile Stations

LTE
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Why LTE?
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Applications:
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Targets:
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Interactive gaming
DVD quality video
Data download/upload
High data rates at high speed
Low latency
Packet optimized radio access technology
Goals:
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Improving efficiency
Lowering costs
Reducing complexity
Improving services
Making use of new spectrum opportunities and better integration with other open
standards (such as WLAN and WiMAX)
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Introduction
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November 2004, 3GPP Rel8: Long-term Evolution (LTE)
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Related specifications are formally known as the evolved UMTS terrestrial
radio access (E-UTRA) and evolved UMTS terrestrial radio access network
(E-UTRAN)
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LTE encompasses the evolution of:
- the radio access through the E-UTRAN
- the non-radio aspects under the term System
Architecture Evolution (SAE)
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Entire system composed of both LTE and SAE is called the
Evolved Packet System (EPS)
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Network Architecture
IP Service Network
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Cost efficient two node
architecture
Fully meshed approach with
tunneling mechanism over IP
network
Access gateway (AGW)
Enhanced Node B (eNB)
AGW
AGW
S1
S1
S1 S1
IP Transport Network
eNB
eNB
X2
eNB
X2
eNB
X2
eNB
X2
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Network Elements
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Protocol overview
Control Plane
UE
User Plane
eNB
NAS
UE
MME
eNB
NAS
NAS
RRC
RRC
Handovers
RRC
RRC
PDCP
PDCP
Ciphering
PDCP
PDCP
RLC
RLC
Segmentation
RLC
RLC
MAC
MAC
HARQ
MAC
MAC
PHY
PHY
Radio bearers
Logical channels
Transport channels
PHY
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PHY
Modulation,
Physical
coding channels
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Frame structure
LTE:
One radio frame, Tf = 307200Ts=10 ms
One slot, Tslot = 15360Ts = 0.5 ms
#0
#1
#2
#3
#18
#19
#13
#14
One subframe
WCDMA/HSPA:
One radio frame, 10 ms
One slot, 2/3ms
#0
#1
#2
#3
One subframe, 2ms
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Channel Dependent Scheduling
and Link adaptation
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Frequency-domain & Time-domain adaptation
Focus transmission power to each user’s best channel portion
Adaptive modulation (QPSK, 16QAM, 64QAM)
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LTE PHY –
Main Technologies
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MIMO
Multiple Input Multiple
Output
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OFDM
Orthogonal Frequency
Division Multiplexing
NRx
NTx
Receive
Antennas
Transmit
Antennas
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LTE PHY - MIMO Basics
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Minimum antenna requirement: 2 at eNodeB 2 Rx at UE
Transmission of several independent data streams in parallel
=> increased data rate
The radio channel consists of NTx x NRx paths
Theoretical maximum rate increase factor = Min(NTx x NRx)
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LTE PHY - OFDM Basics
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Sub-carriers are orthogonal
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All the sub-carriers allocated to a given user
are transmitted in parallel.
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The carrier spacing is 15kHz
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Requirement comparison
Requirement
HSPA (Rel 6)
LTE
Peak data rate
14 Mbps DL
5.76 Mbps UL
100 Mbps DL
50 Mbps UL
5% packet call throughput
64 Kbps DL
5 Kbps UL
3-4x DL / 2-3x UL
improvement
Averaged user throughput
900 Kbps DL
150 Kbps UL
3-4x DL / 2-3x UL
improvement
Control plane capacity
> 200 users per cell (for
5MHz spectrum)
User plane latency
50 ms
5 ms
Call setup time
2 sec
50 ms
Broadcast data rate
384 Kbps
6-8x improvement
Mobility
Up to 250 km/h
Up to 350 km/h (500 km/h
for wider bandwidths)
Bandwidth
5 MHz
1.25, 2.5, 5, 10, 15, 20 MHz
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Feature comparison
Feature
HSPA (Rel 6)
LTE
minimum TTI size
2 ms
1 ms
Modulation
DL: QPSK, 16 QAM
UL: QPSK
DL: QPSK, 16 QAM, 64
QAM
UL: 16 QAM
HARQ
Async DL,
Sync UL
Async DL,
Sync UL
Fast scheduling
TDS (time domain)
TDS and FDS (frequency
domain)
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Conclusion
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Scalable bandwidth
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Downlink and uplink peak data rates are 100 and 50 Mbit/s
respectively for 20 MHz bandwidth.
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MIMO
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OFDM
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At least 200 mobile terminals in the active state for 5MHz bandwidth.
If bandwidth is more than 5MHz, at least 400 terminals should be
supported.
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PHY key technologies enable higher spectral efficiency, peak rate
and lower latency
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