Lte key technologies

ZTE Corporation
2015/11/5
LTE Key Technologies

Content
 LTE Organization
 LTE Basic Technologies
 Key Technology of R9
 Key Technology of R10

Internal use only▲
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© ZTE All rights reserved
Organizations Leading LTE Ecosystem
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Functional
Requirements
protocols
Establishment
LTE/SAE Trial
Initiative
TSG RAN
TSG SA
TSG CT
PCG
TSG GERAN
Members
Sponsors

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Important Role in International Organization
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 Sponsor of the NGMN in Dec. 2006
 Active partner of NGMN
 Working closely with operators in NGMN.
 Joined LSTI in Oct. 2007
 Early member of LSTI to promote LTE/SAE commercial deployment
 Participate in PoC, IOT/IODT trial.
 Join the 3GPP in 1999
 Extensively Contribution to standardization related to LTE/SAE
 Chairmen position in SA5 and 8 report on SA, RAN and CT

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NGMN Trial Group LSTI （LTE/SAE Trial Initiative )
Progress Reports
NGMN Test includes LTE and WiMAX. LSTI ONLY includes LTE testing.
Relationship Between NGMN Trial and LSTI
Testing
Requirements
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Functional Areas LSTI
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3GPP Structure

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LTE Key Feature
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LTE R8 LTE R9 LTE R10
• Variable Bandwidth
• Simple Architecture
• New radio access
• UL:SC-FDMA
• DL:OFDMA
• Multi-antenna
technology
• Transmit diversity
• Spatial multiplexing
• Fast Scheduling
• SON
• Positioning
• eMBMS
• SON
• Enhanced Dual-layer
transmission
• HeNB enhancement
• Pico eNB RF
• Carrier Aggregation
• Relay
• Minimization of Drive
Test
• Latency reduction
• HeNB Mobility
Enhancements
• Extended multi-antenna
• Uplink multiple access
• eICIC
• SON

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10
LTE R8 Key Feature
Variable Bandwidth
1.4, 3, 5, 10, 15 and 20 MHz
Simple Architecture
eNodeB as the only E-UTRAN node
Smaller number of RAN interfaces, eNodeB
eNodeB « MME/SAE-Gateway (S1), eNodeB « eNodeB (X2)
Simple Protocol Architecture
Shared channel based
PS mode only, with VoIP capability
New Radio Access
OFDM in Downlink, Robust against multi-path interference & High affinity to advanced
techniques such as Frequency domain channel-dependent scheduling & MIMO
DFTS-OFDM(“Single-Carrier FDMA”) in Uplink, Low PAPR, User orthogonality in
frequency domain
Multi-antenna Application
Transmit diversity & Spatial multiplexing
Low Latency
Short setup time & Short transfer delay
Short handover latency and interruption time;
Short TTI, RRC procedure, Simple RRC states

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Up to 64 QAM can be used
Resistance to multi-path interference by Cyclic Prefix.
Friendly to MIMO.
OFDMA: Downlink multiple access
Sub-carriers
Sub-frame
Frequency
Time
Time frequency
resource for User 1
Time frequency
resource for User 2
Time frequency
resource for User 3
System Bandwidth

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Up to 16 QAM can be used
Single carrier modulation achieves lower Peak to Average
Ratio (PAPR)
FDMA is efficiently achieved through FFT operation
SC-FDMA: Uplink multiple access

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Subframes are configured as downlink or uplink
Subframe 0 and DwPTS are always used for downlink
Switch period can support 5ms and 10ms
Radio Frame Structure
One
subframe
Subframe #5
DwPTS
GP
UpPTS
… Subframe #9
One half-frame 153600 TS = 5
ms
One
subframe
Subframe #0
DwPTS
GP
UpPTS
30720TS
… Subframe #4
One slot
Tslot=15360TS
One radio frame Tf = 307200 Ts = 10 ms

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TDD
D U U U D D D D D
DL/UL flexible configuration:
Different with FDD technology, TD-LTE can adjust DL/UL time
configuration to meet asymmetric services according different
service types.
Period DL/UL configuration
5 ms 1DL:3UL, 2DL:2UL, 3DL:1UL
10 ms 6DL:3UL, 7DL:2UL, 8DL:1UL, 3DL:5UL
10ms
6 : 3
7 : 2
8 : 1
5ms 5ms
3 : 5
Downlink Uplink DwPTS+GP+UpPTS
5ms
1 : 3
5ms
2 : 2
5ms
3 : 1
TD-LTE Advantage
Flexible Configuration Meets Diversified Services

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3GPP Specification(36.213) provides the tables showing the
mapping between MCS (Modulation and Coding Scheme)
index and TBS (Transport Block Size)
TBS indicates the throughput.
Tables in the Specification 36.213
– Table(7.1.7.1-1): DL mapping between MCS index with TBS index.
– Table(8.6.1-1): UL mapping between MCS index with TBS index
– Table(7.1.7.2.1-1): mapping between TBS index + NPRB with TBS.
TD-LTE Peak Throughput Calculation

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Step 1: ITBS from Table 7.1.7.1 of 3GPP 36.213.
Step 2: TBsize from Table 7.1.7.2.1 -1 of 3GPP 36.213
Step 3: Calculation formula:
Throughput =
（（Num of D）*（TBSize of D）+ （Num of S）*（TBSize of S））/ (Time of TTI)
– Number of D : Downlink subframe number
– TBsize of D : TBSize of downlink from 3GPP TBS table(7.1.7.2.1-1)
– Num of S : Number of special subframe, special s can be used for DL data transmission.
– TBSize of S : TBSize of 3GPP TBS table(7.1.7.2.1-1),
3GPP set the NPRB of S = NPRB of D * 0.75, then use the NPRB of
S to get TBSize from table (7.1.7.2.1.-1)
– Time of TTI = 10ms
Throughput Calculation for DL

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Transport
Block
Concept of TB (Transport block)
TBSize: Size of TB(bit).
Transport block (TB): is a group of resource blocks with a common modulation/coding.
The physical resource is a transport block, which corresponds to the data carried in a period of
time .

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DL Step 1: Get ITBS
Qm
2 QPSK
4 16QAM
6 64QAM
7.1.7.1-1 table Modulation and TBS Index Table for PDSCH(3GPP 36.213)
Set IMCS = 28
ITBS = 26

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DL Step 2: Get TBSize
Table 7.1.7.2.1-1: Transport block size table
• Itbs = 26
• NPRB = 100, TBSize of D = 75376 bits
• For Special subframe NPRB’ = 100 * 0.75 = 75, TBSize of S = 55056 bits

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Throughput =
（（Num of D）*（TBSize of D）+ （Num of S）*（TBSize of S））/ (Time of TTI)
– Timeslot Configuration : 2 ,2DL:2UL,
4 DL subframe per frame(10ms).
– Num of D = 4
– TBSize of D = 75376 bits
– Num of S = 2
– TBSize of S = 55056 bits
Throughput = (75736 * 4 + 55056*2)/10ms = 41.31 Mbps
For 2X2 MIMO, We assume peak throughput = 41.31 * 2 = 82.62Mbps
DL Step 3: Calculation

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Step 1: ITBS from Table (8.6.1-1)
Step 2: TBsize from Table 7.1.7.2.1 -1
Step 3: Calculation formula:
Throughput = ((Num of U)*(TBSize of U)/ (Time of TTI))
– Num of U : Number of UL subframe
– TBsize of U: TBSize from table 7.1.7.2.1-1 of UL subframe
– Time of TTI : 10ms
Throughput Calculation for UL

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Step 1: Get ITBS
Set IMCS = 17
ITBS = 16

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Step 2: Get TBSize
Set ITBS = 16, NPRB = 100
TBSize = 32856 bits

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Throughput = ((Num of U)*(TBSize of U)/ 10ms)
Timeslot Configuration : 2
2DL:2UL,
4 DL sub frame per frame(10ms).
Num of U = 4
TBSize of U = 32856
Throughput = 4 * 32856 / 10ms = 13.142Mbps
Step 3: Calculation

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Basic antenna configuration: 2*2 downlink, 1*2 uplink
Maximum antenna configuration: 4*4
Basic Concept of MIMO
 Improve spectrum efficiency based on space and time
processing technology
 Diversity: reduce the interference caused by channel
fading
 Spatial Multiplexing: gain the multiplied data rates
 Beamforming: weight the Tx vector to form the
directional beam

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RX
Data
Encode
Encode
Channel
Interleave
Channel
Interleave
Modulator
QPSK
16QAM
Modulator
QPSK
16QAM
Detector
Detector
MUX
Data
v12
v21
v11
v22
TX
DeMUX
Space multiplexing & space diversity leads to higher bit rate.
MIMO Principle

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Functions, Features and Objective
Functions Features Objective
2G/3G LTE
 SON: avoid manual
intervention
SON-
enable
SON
Self-
maintenance
Self-
configuration
Self-
optimization
Self-
healing
SON
Enable
SON

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Self-configuration and Self-optimization
Procedures
eNB power on
(or cable
connected)
(A) Basic Setup
(B) Initial Radio
Configuration
(C)Optimization
/Adaptation
configuration of IP address
and detection of OAM
authentication of eNB/NW
association to aGW
downloading of eNB
software (and operational
parameters)
coverage/capacity related
parameter configuration
neighbour list configuration
neighbour list optimisation
coverage and capacity
control
Self-Configuration
(pre-operational
state)
Self-Optimisation
(operational state)

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LTE R9 Key Technique –Enhanced Dual-Layer Transmission
Single User Dual-Layer BF
MOD
Channel
Encoder
Channel
Encoder
MOD
Code
Word
Layer
Mapping
MUX
MUX
Beam
Forming
VA-PA(MS BF)
Same Time-Frequency
DRS

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31
MOD
Channel
Encoder
Channel
Encoder
MOD
Code
Word
Layer
Mapping
MUX
MUX
Beam
Forming
VA-PA(MS BF)
Same Time-Frequency
DRS
SDMA based on Dual-
stream beam forming

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 Beam Forming (BF) is helping to reach high system capacity and large coverage;
 BF is beneficial for increasing cell throughput and especially essential to users
at cell edge
 LTE Rel-8 already supports single-layer BF based on user-specific
Reference Symbols(RS);
 Multi-layer BF is proposed for LTE Rel-9.
Radio Link Enhancement Techniques were added for LTE.
Support single user dual-layer BF using UE specific RS for both LTE-TDD and FDD;
Design of UE specific demodulation reference signals and mapping of physical data
channel to resource elements aims for forward compatibility with LTE-A Demodulation RS;
Principles exploiting channel reciprocity were considered in the feedback design where
applicable.
Background for Enhanced Dual-Layer Transmission

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LTE R9 Key Technique –Architecture with Deployed HeNB GW
E-UTRAN
MME / S-GW MME / S-GW
HeNB GW
X2
X2
X2
S1
S1
S1
S1
S1
S1
S1
S1
S1
HeNB HeNB
HeNB
eNB eNB
eNB

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LTE R9 Key Technique – HeNB & HeNB GW
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 The HeNB hosts the same functions as an eNB.
 One HeNB serves only one cell.
 The S1 interface between the HeNB and the EPC to scale to
support a large number of HeNBs.
 The S1 interface between the HeNB and the EPC is the
same whether the HeNB is connected to the EPC via a
HeNB GW or not.
 This version of the specification does not support X2
connectivity of HeNBs.
 The HeNB GW serves as a concentrator for the C-Plane,
specifically the S1-MME interface.

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© ZTE All rights reserved 36
Uplink
Band 1
Uplink
Band 2
Aggregation
Different
Frequency
Cell 1
Downlink
Band 1
Downlink
Band 2
LTE R10 Key Technique – Carrier Aggregation，
CA
Different
Frequency
Cell 2
Uplink Band
1+2
Aggregation
Cell
Downlink Band
1+2

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37
LTE R10 Key Technique – Carrier Aggregation，
CA
What is Carrier Aggregation?
 2 carriers or more aggregated, the bandwidth up to 100MHz;
 Improve peak throughput and system throughput;
To solve the problem of discontinuous carrier;
Terminal can receive or transmission multiple carriers;
Continuous carriers can aggregate, discontinuous carriers can also aggregate;
Each carrier maximum supports100RBs;
Each carrier of UE can only see a transmission block and HARQ function entity;
Each transmission block can only mapped to a carrier.

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LTE R10 Key Technique – Relay，CA
EPC
E-NodeB
Relay Station
MME/ S-GW
X2 Interface
S1 Interface
E-NodeB
E-NodeB

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LTE R10 Key Technique – Relay
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1 Why Introduce Relay?
 Group Mobility
Reduce handover interrupt time, increase throughput
 Provide Temporary Coverage
Avoid a large number cable deployment, lower CAPEX & OPEX
 Improve Cell Edge Throughput
Improve the reception quality effectively of cell edge users
 New Area Coverage
Improve spectrum efficiency with Introducing Relay Station in city region
or hot spots

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