LTE: Introduction, evolution and testing

UMTS Long Term Evolution (LTE) technology intro + evolution measurement aspects

Reiner Stuhlfauth

[email protected]

Training Centre

Rohde & Schwarz, Germany

Subject to change – Data without tolerance limits is not binding.

R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG. Trade names are trademarks

of the owners.

2011 ROHDE & SCHWARZ GmbH & Co. KG

Test & Measurement Division

- Training Center -

ROHDE & SCHWARZ GmbH reserves the copy right to all of any part of these course notes.

Permission to produce, publish or copy sections or pages of these notes or to translate them must first

be obtained in writing from

ROHDE & SCHWARZ GmbH & Co. KG, Training Center, Mühldorfstr. 15, 81671 Munich, Germany

November 2012 | LTE Introduction | 2

2013/2014 2009/2010

Technology evolution path

GSM/

GPRS

EDGE, 200 kHz DL: 473 kbps

UL: 473 kbps

EDGEevo DL: 1.9 Mbps

UL: 947 kbps

HSDPA, 5 MHz DL: 14.4 Mbps

UL: 2.0 Mbps

HSPA, 5 MHz DL: 14.4 Mbps

UL: 5.76 Mbps

HSPA+, R7 DL: 28.0 Mbps

UL: 11.5 Mbps

2005/2006 2007/2008 2011/2012

HSPA+, R8 DL: 42.0 Mbps

UL: 11.5 Mbps

cdma

2000

1xEV-DO, Rev. 0

1.25 MHz DL: 2.4 Mbps

UL: 153 kbps

1xEV-DO, Rev. A


UL: 1.8 Mbps

1xEV-DO, Rev. B


UL: 4.9 Mbps

HSPA+, R9 DL: 84 Mbps

UL: 23 Mbps

DO-Advanced DL: 32 Mbps and beyond

UL: 12.4 Mbps and beyond

LTE-Advanced R10 DL: 1 Gbps (low mobility)

UL: 500 Mbps

Fixed WiMAX

scalable bandwidth 1.25 … 28 MHz

typical up to 15 Mbps

Mobile WiMAX, 802.16e

Up to 20 MHz DL: 75 Mbps (2x2)

UL: 28 Mbps (1x2)

Advanced Mobile

WiMAX, 802.16m DL: up to 1 Gbps (low mobility)

UL: up to 100 Mbps

VAMOS Double Speech

Capacity

HSPA+, R10 DL: 84 Mbps

UL: 23 Mbps

LTE (4x4), R8+R9, 20MHz DL: 300 Mbps

UL: 75 Mbps

UMTS DL: 2.0 Mbps

UL: 2.0 Mbps


Why LTE? Ensuring Long Term Competitiveness of UMTS

l LTE is the next UMTS evolution step after HSPA and HSPA+.

l LTE is also referred to as

EUTRA(N) = Evolved UMTS Terrestrial Radio Access (Network).

l Main targets of LTE:

l Peak data rates of 100 Mbps (downlink) and 50 Mbps (uplink)

l Scaleable bandwidths up to 20 MHz

l Reduced latency

l Cost efficiency

l Operation in paired (FDD) and unpaired (TDD) spectrum


Peak data rates and real average throughput (UL)

0,174

0,473

2 2

0,947

0,153

1,8

5,76

11,5

58

0,1

15

0,1

0,03

0,1

0,2

0,5

0,7

2

5

0,01

0,1

1

10

100

GPRS

(Rel. 97)

EDGE

(Rel. 4)

1xRTT WCDMA

(Rel. 99/4)

E-EDGE

(Rel. 7)

1xEV-DO

Rev. 0

1xEV-DO

Rev. A

HSPA

(Rel. 5/6)

HSPA+

(Rel. 7)

LTE 2x2

(Rel. 8)

Technology

Da

ta r

ate

in

Mb

ps

max. peak UL data rate [Mbps] max. avg. UL throughput [Mbps]


Comparison of network latency by technology

710

190

320

46

158

85

70

30

0

100

200

300

400

500

600

700

800

GPRS

(Rel. 97)

EDGE

(Rel. 4)

WCDMA

(Rel. 99/4)

HSDPA

(Rel. 5)

HSUPA

(Rel. 6)

E-EDGE

(Rel. 7)

HSPA+

(Rel. 7)

LTE

(Rel. 8)

Technology

2G

/ 2

.5G

la

ten

cy

0

20

40

60

80

100

120

140

160

3G

/ 3

.5G

/ 3

.9G

la

ten

cy

Total UE Air interface Node B Iub RNC Iu + core Internet


Round Trip Time, RTT

Serving

RNC

MSC

SGSN

Iub/Iur Iu

•ACK/NACK

generation in RNC

MME/SAE Gateway

•ACK/NACK

generation in node B

Node B

eNode B

TTI

~10msec

TTI

=1msec


Multi-RAT requirements

(GSM/EDGE, UMTS, CDMA)

MIMO multiple antenna

schemes

Timing requirements

(1 ms transm.time interval)

New radio transmission

schemes (OFDMA / SC-FDMA)

Major technical challenges in LTE

Throughput / data rate

requirements

Scheduling (shared channels,

HARQ, adaptive modulation)

System Architecture

Evolution (SAE)

FDD and

TDD mode


Introduction to UMTS LTE: Key parameters

Frequency

Range UMTS FDD bands and UMTS TDD bands

Channel

bandwidth,

1 Resource

Block=180 kHz

1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz

6

Resource

Blocks

15

Resource

Blocks

25

Resource

Blocks

50

Resource

Blocks

75

Resource

Blocks

100

Resource

Blocks

Modulation

Schemes

Downlink: QPSK, 16QAM, 64QAM

Uplink: QPSK, 16QAM, 64QAM (optional for handset)

Multiple Access Downlink: OFDMA (Orthogonal Frequency Division Multiple Access)

Uplink: SC-FDMA (Single Carrier Frequency Division Multiple Access)

MIMO

technology

Downlink: Wide choice of MIMO configuration options for transmit diversity, spatial

multiplexing, and cyclic delay diversity (max. 4 antennas at base station and handset)

Uplink: Multi user collaborative MIMO

Peak Data Rate

Downlink: 150 Mbps (UE category 4, 2x2 MIMO, 20 MHz)

300 Mbps (UE category 5, 4x4 MIMO, 20 MHz)

Uplink: 75 Mbps (20 MHz)


E-UTRA

Operating

Band

Uplink (UL) operating band

BS receive UE transmit

Downlink (DL) operating band

BS transmit UE receive Duplex Mode

FUL_low – FUL_high FDL_low – FDL_high

1 1920 MHz – 1980 MHz 2110 MHz – 2170 MHz FDD




5 824 MHz – 849 MHz 869 MHz – 894MHz FDD




9 1749.9 MHz – 1784.9 MHz 1844.9 MHz – 1879.9 MHz FDD


11 1427.9 MHz – 1452.9 MHz 1475.9 MHz – 1500.9 MHz FDD







20 832 MHz - 862 MHz 791 MHz - 821 MHz FDD

21 1447.9 MHz - 1462.9 MHz 1495.9 MHz - 1510.9 MHz FDD

22 3410 MHz - 3500 MHz 3510 MHz - 3600 MHz FDD

LTE/LTE-A Frequency Bands (FDD)


LTE/LTE-A Frequency Bands (TDD)

E-UTRA

Operating

Band

Uplink (UL) operating band

BS receive UE transmit

Downlink (DL) operating band

BS transmit UE receive Duplex Mode

FUL_low – FUL_high FDL_low – FDL_high

33 1900 MHz – 1920 MHz 1900 MHz – 1920 MHz TDD








41 3400 MHz –

3600MHz

3400 MHz –

3600MHz TDD


l OFDM is the modulation scheme for LTE in downlink and

uplink (as reference)

l Some technical explanation about our physical base: radio

link aspects

Orthogonal Frequency Division Multiple Access


What does it mean to use the radio channel?

Using the radio channel means to deal with aspects like:

Doppler effect Time variant channel

Frequency selectivity

C

A

D

BReceiverTransmitter

MPP

attenuation


Still the same “mobile” radio problem: Time variant multipath propagation

C

A

D

BReceiverTransmitter

A: free space

B: reflection

C: diffraction

D: scattering

A: free space B: reflection C: diffraction D: scattering

reflection: object is large compared to wavelength

scattering: object is small or its surface irregular

Multipath Propagation

and Doppler shift


Multipath channel impulse response

path delay path attenuation path phase

1

0

, i

Lj t

i i

i

h t a t e

The CIR consists of L resolvable propagation paths

delay spread

|h|²


Radio Channel – different aspects to discuss

Bandwidth

Wideband Narrowband

Symbol duration

Short symbol

duration

Long symbol

duration

t t

Repetition rate of pilots?

Channel estimation:

Pilot mapping

or

or

Time? Frequency?

frequency distance of pilots?


Frequency selectivity - Coherence Bandwidth

Frequency selectivity

f

power

Wideband = equalizer

Must be frequency selective

Narrowband = equalizer

Can be 1 - tap

Here: find

Math. Equation

for this curve

Here: substitute with single

Scalar factor = 1-tap

How to combat

channel influence?


Time-Invariant Channel: Scenario

Transmitter Fixed Receiver

Fixed Scatterer

Delay Delay spread

Transmitter

Signal

t

Receiver

Signal

t

→time dispersive

ISI: Inter Symbol

Interference:

Happens, when

Delay spread >

Symbol time

Successive

symbols

will interfere Channel Impulse Response, CIR

collision


t

f TSC

|H(f)|

Motivation: Single Carrier versus Multi Carrier

|h(t)|

t

B

l Frequency Domain

l Coherence Bandwidth Bc < Systembandwidth B

→ Frequency Selective Fading → equalization effort

l Time Domain

l Delay spread > Symboltime TSC

→ Inter-Symbol-Interference (ISI) → equalization effort

1

SC

BT

Source: Kammeyer; Nachrichtenübertragung; 3. Auflage


|h(t)|

t

t

f

f

t

TSC |H(f)|

1

SC

BT

1

MC

Bf

N T

MC SCT N T

Motivation: Single Carrier versus Multi Carrier

B

B

|H(f)|

Source: Kammeyer; Nachrichtenübertragung; 3. Auflage


What is OFDM?

Single carrier

transmission,

e.g. WCDMA

Broadband, e.g. 5MHz for WCDMA

Orthogonal

Frequency

Division

Multiplex Several 100 subcarriers, with x kHz spacing


Idea: Wide/Narrow band conversion

One high rate signal:

Frequency selective fading

N low rate signals:

Frequency flat fading

S/P

t / Tb t / Ts

… … …

ƒ

H(ƒ) h(τ)

τ

h(τ)

τ

„Channel

Memory“


OFDM signal generation

00 11 10 10 01 01 11 01 …. e.g. QPSK

h*(sinjwt + cosjwt) h*(sinjwt + cosjwt)

OFDM

symbol

duration Δt

Frequency

time

=> Σ h * (sin.. + cos…)


COFDM

X

X Ma

pp

er

+

X

X Ma

pp

er

+

....

. OFDM

symbol Σ

Data

with

FEC

overhead


Fourier Transform, Discrete FT

;)()(

;)()(

2

2

dfefHth

dtethfH

tfj

tfj

;1

);2sin()2cos(

1

0

2

1

0

1

0

1

0

/2

N

n

N

nkj

nk

N

k

k

N

k

k

N

k

Nnkj

kn

eHN

h

N

nkhj

N

nkhehH

Fourier Transform

Discrete Fourier Transform (DFT)


OFDM Implementation with FFT (Fast Fourier Transformation)

Receiver

Transmitter Channel

n(n)

(k) b

h(n)

r(n)

S/P

P/S

( ) ˆ b k P/S

IDF

T N

FF

T

Map

Map

Map

S/P

DF

T N

FF

T

d(0)

d(1)

Demap

Demap

Demap

s(n)

d(FFT-1)

d(FFT-1)

d(0)

d(1)

.

.

.

.

.

.


-1 -0.5 0 0.5 1-70

-60

-50

-40

-30

-20

-10

0

10

Sx

x

f f -1

f -2

f 1

f 2

f 0

Problem of MC - FDM

Overlapp of neighbouring subcarriers

→ Inter Carrier Interference (ICI).

Solution

“Special” transmit gs(t) and receive filter gr(t) and frequencies fk allows orthogonal

subcarrier

→ Orthogonal Frequency Division Multiplex (OFDM)

Inter-Carrier-Interference (ICI)

ICI

MCS f


Rectangular Pulse

Δt

Δf

t

f

A(f)

sin(x)/x Convolution

time frequency


Orthogonality

Δf

Orthogonality condition: Δf = 1/Δt


ISI and ICI due to channel

l Symbol l-1 l+1

n

h n

Delay spread

Receiver DFT

Window

fade in (ISI) fade out (ISI)


ISI and ICI: Guard Intervall

l Symbol l-1 l+1

n

h n

Delay spread

Receiver DFT

Window

GT Delay Spread

Guard Intervall guarantees the supression of ISI!


Receiver DFT

Window

Guard Intervall as Cyclic Prefix

l Symbol l-1 l+1

n

h n

Delay spread

GT Delay Spread

Cyclic Prefix guarantees the supression of ISI and ICI!

Cyclic Prefix


Synchronisation

Cyclic Prefix

CP CP CP CP

:S ymbolOFDM

Metric

1ll1l

n~

Search window -


Frequency Domain Time Domain

DL CP-OFDM signal generation chain

l OFDM signal generation is based on Inverse Fast Fourier Transform

(IFFT) operation on transmitter side:

Data

source

QAM

Modulator 1:N

N

symbol

streams

IFFT OFDM

symbols N:1 Cyclic prefix

insertion

Useful

OFDM

symbols

l On receiver side, an FFT operation will be used.


OFDM: Pros and Cons

Pros:

scalable data rate

efficient use of the available bandwidth

robust against fading

1-tap equalization in frequency domain

Cons:

high crest factor or PAPR. Peak to average power ratio

very sensitive to phase noise, frequency- and clock-offset

guard intervals necessary (ISI, ICI) → reduced data rate


MIMO = Multiple Input Multiple Output Antennas


MIMO is defined by the number of Rx / Tx Antennas and not by the Mode which is supported Mode

SISO Single Input Single Output

1 1 Typical todays wireless Communication System

MISO Multiple Input Single Output

1 1

M

Transmit Diversity

l Maximum Ratio Combining (MRC)

l Matrix A also known as STC

l Space Time / Frequency Coding (STC / SFC)

SIMO Single Input Multiple Output

1 1

M

Receive Diversity

l Maximum Ratio Combining (MRC)

MIMO Multiple Input Multiple Output

1 1

M M

Definition is seen from Channel

Multiple In = Multiple Transmit Antennas

Receive / Transmit Diversity

Spatial Multiplexing (SM) also known as:

l Space Division Multiplex (SDM)

l True MIMO

l Single User MIMO (SU-MIMO)

l Matrix B

Space Division Multiple Access (SDMA) also known as:

l Multi User MIMO (MU MIMO)

l Virtual MIMO

l Collaborative MIMO

Beamforming


MIMO modes in LTE

-Tx diversity

-Beamforming

-Rx diversity

-Multi-User MIMO

-Spatial Multiplexing

Better S/N

Increased

Throughput at

Node B

Increased

Throughput per

UE


RX Diversity

Maximum Ratio Combining depends on different fading of the

two received signals. In other words decorrelated fading

channels


TX Diversity: Space Time Coding

The same signal is transmitted at differnet

antennas

Aim: increase of S/N ratio

increase of throughput

Alamouti Coding = diversity gain

approaches

RX diversity gain with MRRC!

-> benefit for mobile communications

data

Fading on the air interface

*

12

*

21

2ss

ssS

Alamouti Coding

time

space


MIMO Spatial Multiplexing

SISO:

Single Input

Single Output

MIMO:

Multiple Input

Multiple Output

Increasing

capacity per cell

C=B*T*ld(1+S/N)

) , min(

1

) 1 ( R T N N

i

i

i

i

N

S ld B T C ?

Higher capacity without additional spectrum!


The MIMO promise

l Channel capacity grows linearly with antennas

l Assumptions l Perfect channel knowledge l Spatially uncorrelated fading

l Reality

l Imperfect channel knowledge l Correlation ≠ 0 and rather unknown

Max Capacity ~ min(NTX, NRX)


Spatial Multiplexing

Throughput:

data

Coding Fading on the air interface

data

100% 200% <200%

Spatial Multiplexing: We increase the throughput

but we also increase the interference!


Correlation of

propagation

pathes

Transmitter Receiver

h11

h21

hMR1

h1MT

h12

h22

hMR2

h2MT

hMRMT

s1

s2

sNTx

r1

r2

rNRx

H s r

Introduction – Channel Model II

NTx

antennas NRx

antennas

Capacity ~ min(NTX, NRX) → max. possible rank!

But effective rank depends on channel, i.e. the

correlation situation of H

Rank indicator

estimates


Spatial Multiplexing prerequisites

Decorrelation is achieved by:

l Decorrelated data content on each spatial stream

l Large antenna spacing

l Environment with a lot of scatters near the antenna

(e.g. MS or indoor operation, but not BS)

l Precoding

l Cyclic Delay Diversity

But, also possible

that decorrelation

is not given

difficult

Channel

condition

Technical

assist


MIMO: channel interference + precoding

MIMO channel models: different ways to combat against

channel impact:

I.: Receiver cancels impact of channel

II.: Precoding by using codebook. Transmitter assists receiver in

cancellation of channel impact

III.: Precoding at transmitter side to cancel channel impact


MIMO: Principle of linear equalizing

H-1

LE

s

n

r ^ r

H Tx

Rx

The receiver multiplies the signal r with the

Hermetian conjugate complex of the transmitting

function to eliminate the channel influence.

R = S*H + n

Transmitter will send reference signals or pilot sequence

to enable receiver to estimate H.


SISO: Equalizer has to estimate 1 channel

Linear equalization – compute power increase

H = h11

h21

h12

h22

h11 H = h11

h11

h12

h21 h22

2x2 MIMO: Equalizer has to estimate 4 channels


receiver

channel

transmitter

transmission – reception model

A H R +

noise

s r

•Modulation,

•Power

•„precoding“,

•etc.

•detection,

•estimation

•Eliminating channel

impact

•etc. Linear equalization

at receiver is not

very efficient, i.e.

noise can not be cancelled


MIMO – work shift to transmitter

Transmitter Receiver Channel


MIMO Precoding in LTE (DL) Spatial multiplexing – Code book for precoding

Codebook index

Number of layers

1 2

0

0

1

10

01

2

1

1

1

0

11

11

2

1

2

1

1

2

1

jj

11

2

1

3

1

1

2

1 -

4

j

1

2

1 -

5

j

1

2

1 -

Code book for 2 Tx:

Additional multiplication of the

layer symbols with codebook

entry


MIMO precoding

+

+

precoding

precoding

t

t

1

1

t t

∑=0

1

-1

1

1

Ant1

Ant2

2

∑


receiver

channel

transmitter

MIMO – codebook based precoding

A H R +

noise

s r

Precoding

codebook

Precoding Matrix Identifier, PMI

Codebook based precoding creates

some kind of „beamforming light“


MIMO: avoid inter-channel interference – future outlook

Idea: F adapts transmitted signal to current channel conditions

Link adaptation

Transmitter

F

H +

+

Space time

receiver

xk yk

V1,k

VM,k

Feedback about H

e.g. linear precoding:

Y=H*F*S+V

S


MAS: „Dirty Paper“ Coding – future outlook

l Multiple Antenna Signal Processing: „Known Interference“

l Is like NO interference

l Analogy to writing on „dirty paper“ by changing ink color accordingly

„Known

Interference

is No

Interference“

„Known

Interference

is No

Interference“

„Known

Interference

is No

Interference“

„Known

Interference

is No

Interference“


Spatial Multiplexing

data

Codeword Fading on the air interface

data

Spatial Multiplexing: We like to distinguish the 2 useful

Propagation passes:

How to do that? => one idea is SVD

Codeword


Idea of Singular Value Decomposition

know

Singular Value

Decomposition

r = H s + n

s1

s2

r1

r2

channel H

MIMO

wanted

r = D s + n ~ ~ ~

s1

s2

r1

r2

channel D

~

~ ~

~ SISO


Singular Value Decomposition (SVD)

r = H s + n

H = U Σ (V*)T

00

0

00

00

00

3

2

1

U = [u1,...,un] eigenvectors of (H*)T H

V = [v1,...,vm] eigenvectors of H (H*)T

i isingular values

i eigenvalues of (H*)T H

~ r = (U*)T r

s = (V*)T s ~

n = (U*)T n ~

r = Σ s + n ~ ~ ~


MIMO: Signal processing considerations MIMO transmission can be expressed as

r = Hs+n which is, using SVD = UΣVHs+n

Imagine we do the following:

1.) Precoding at the transmitter:

Instead of transmitting s, the transmitter sends s = V*s

2.) Signal processing at the receiver

Multiply the received signal with UH, r = r*UH

So after signal processing the whole signal can be expressed as:

r =UH*(UΣVHVs+n)=UHU Σ VHVs+UHn = Σs+UHn

=InTnT =InTnT

s1

s2

n2

r1

r2

U VH

σ1

σ2

Σ

n1

UH V


MIMO: limited channel feedback

s1

s2

n2

r1

r2

U VH

σ1

σ2

Σ

n1

UH V

Transmitter Receiver

Idea 1: Rx sends feedback about full H to Tx.

-> but too complex,

-> big overhead

-> sensitive to noise and quantization effects

H

Idea 2: Tx does not need to know full H, only unitary matrix V

-> define a set of unitary matrices (codebook) and find one matrix in the codebook that

maximizes the capacity for the current channel H

-> these unitary matrices from the codebook approximate the singular vector structure

of the channel

=> Limited feedback is almost as good as ideal channel knowledge feedback


Transmitter

Time

Delay

A1

A2

D

B

Cyclic Delay Diversity, CDD

Amp

litud

e

Delay Spread

+

+

precoding

precoding

Multipath propagation

No multipath propagation

Time

Delay


„Open loop“ und „closed loop“ MIMO

nHWsr

nHsr

Open loop (No channel knowledge at transmitter)

Closed loop (With channel knowledge at transmitter

Adaptive Precoding matrix („Pre-equalisation“)

Feedback from receiver needed (closed loop)

Channel

Status, CSI

Rank indicator

Channel

Status, CSI

Rank indicator


MIMO transmission modes

Transmission mode1

SISO

Transmission mode2

TX diversity Transmission mode3

Open-loop spatial

multiplexing

Transmission mode4

Closed-loop spatial

multiplexing

Transmission mode5

Multi-User MIMO

Transmission mode6

Closed-loop

spatial multiplexing,

using 1 layer

Transmission mode7

SISO, port 5

= beamforming in TDD

7 transmission

modes are

defined

Transmission mode is given by higher layer IE: AntennaInfo


Beamforming

Adaptive Beamforming Closed loop precoded

beamforming

•Classic way

•Antenna weights to adjust beam

•Directional characteristics

•Specific antenna array geometrie

•Dedicated pilots required

•Kind of MISO with channel

knowledge at transmitter

•Precoding based on feedback

•No specific antenna

array geometrie

•Common pilots are sufficient


Spatial multiplexing vs beamforming

Spatial multiplexing increases throughput, but looses coverage


Spatial multiplexing vs beamforming

Beamforming increases coverage


Basic OFDM parameter

2048

84.3256

115

FFT

FFTs

FFTs

N

McpsN

F

fNF

TkHzf

LTE

Data symbols

f

S/P Sub - carrier Mapping

CP insertion

Size - N FFT

Coded symbol rate= R

N TX

IFFT


LTE Downlink: Downlink slot and (sub)frame structure

Ts = 32.522 ns

#0 #0 #1 #1 #2 #2 #3 #3 #19 #19

One slot, T slot = 15360 T s = 0.5 ms

One radio frame, T f = 307200 T s = 10 ms

#18 #18

One subframe

We talk about 1 slot, but the minimum resource is 1 subframe = 2 slots !!!!!

2048150001s T

Symbol time, or number of symbols per time slot is not fixed


Resource block definition 1 slot = 0,5msec

12 s

ub

carr

iers

DLsymbN

ULsymbNor

Resource element

Resource block

=6 or 7 symbols

In 12 subcarriers

6 or 7,

Depending on

cyclic prefix


time

frequency

1 resource block =

180 kHz = 12 subcarriers

1 slot = 0.5 ms =

7 OFDM symbols**

1 subframe =

1 ms= 1 TTI*=

1 resource block pair

LTE Downlink OFDMA time-frequency multiplexing

*TTI = transmission time interval

** For normal cyclic prefix duration

Subcarrier spacing = 15 kHz

QPSK, 16QAM or 64QAM modulation

UE1

UE4

UE3

UE2

UE5

UE6


LTE: new physical channels for data and control

Physical Downlink Control Channel PDCCH: Downlink and uplink scheduling decisions

Physical Downlink Shared Channel PDSCH: Downlink data

Physical Control Format Indicator Channel PCFICH: Indicates Format of PDCCH

Physical Hybrid ARQ Indicator Channel PHICH: ACK/NACK for uplink packets

Physical Uplink Control Channel PUCCH: ACK/NACK for downlink packets, scheduling requests, channel quality info

Physical Uplink Shared Channel PUSCH: Uplink data


LTE Downlink: FDD channel mapping example

RB Subcarrier #0


LTE Downlink: baseband signal generation

OFDM

Mapper

OFDM signal

generationLayer

Mapper

Scrambling

Precoding

Modulation

Mapper

Modulation

Mapper

OFDM

Mapper

OFDM signal

generationScrambling

code words layers antenna ports

Avoid

constant

sequences

QPSK

16 QAM

64 QAM

For MIMO

Split into

Several

streams if

needed

Weighting

data

streams for

MIMO

1 OFDM

symbol per

stream

1 stream =

several

subcarriers,

based on

Physical

ressource

blocks


Transportation block size

FEC User data

Flexible ratio between data and FEC = adaptive coding

Adaptive modulation and coding


Channel Coding Performance


Automatic repeat request, latency aspects

Network UE

Round

Trip

Time

Transport block

•Transport block size = amount of

data bits (excluding redundancy!)

•TTI, Transmit Time Interval = time

duration for transmitting 1 transport

block

ACK/NACK

Immediate acknowledged or non-acknowledged

feedback of data transmission


HARQ principle: Multitasking

t

Tx

Rx

process

Data

Δt = Round trip time

Demodulate, decode, descramble,

FFT operation, check CRC, etc.

ACK/NACK

Processing time for receiver

Rx

process

Demodulate, decode, descramble,

FFT operation, check CRC, etc.

ACK/NACK

Data Data Data Data Data Data Data Data Data

Described as 1 HARQ process


LTE Round Trip Time RTT

t=0 t=1 t=2 t=3 t=4 t=5 t=6 t=7 t=8 t=9 t=0 t=1 t=2 t=3 t=4 t=5

PD

CC

H

UL

Data

PH

ICH

AC

K/N

AC

K

HA

RQ

Data

Downlink

Uplink

n+4 n+4 n+4

1 frame = 10 subframes

8 HARQ processes

RTT = 8 msec


HARQ principle: Soft combining

lThis is an example of channel coding

l T i is a e am l o h n e co i g

l hi i n x m le f cha n l c ing

l Thi is an exam le of channel co ing

1st transmission with puncturing scheme P1

2nd transmission with puncturing scheme P2

Soft Combining = Σ of transmission 1 and 2

Final decoding


Hybrid ARQ Chase Combining = identical retransmission

Turbo Encoder output (36 bits)

Rate Matching to 16 bits (Puncturing)

Chase Combining at receiver

Systematic Bits

Parity 1

Parity 2

Systematic Bits

Parity 1

Parity 2

Systematic Bits

Parity 1

Parity 2

Original Transmission Retransmission

Transmitted Bit

Punctured Bit


Hybrid ARQ Incremental Redundancy

Turbo Encoder output (36 bits)

Rate Matching to 16 bits (Puncturing)

Incremental Redundancy Combining at receiver

Systematic Bits

Parity 1

Parity 2

Systematic Bits

Parity 1

Parity 2

Systematic Bits

Parity 1

Parity 2

Original Transmission Retransmission

Punctured Bit


LTE Physical Layer: SC-FDMA in uplink

Single Carrier Frequency Division

Multiple Access


LTE Uplink: How to generate an SC-FDMA signal in theory?

LTE provides QPSK,16QAM, and 64QAM as uplink modulation schemes

DFT is first applied to block of NTX modulated data symbols to transform them into

frequency domain

Sub-carrier mapping allows flexible allocation of signal to available sub-carriers

IFFT and cyclic prefix (CP) insertion as in OFDM

Each subcarrier carries a portion of superposed DFT spread data symbols

Can also be seen as “pre-coded OFDM” or “DFT-spread OFDM”

DFT Sub-carrier Mapping

CP insertion

Size-NTX Size-NFFT

Coded symbol rate= R

NTX symbols

IFFT


LTE Uplink: How does the SC-FDMA signal look like?

In principle similar to OFDMA, BUT:

In OFDMA, each sub-carrier only carries information related to one specific symbol

In SC-FDMA, each sub-carrier contains information of ALL transmitted symbols


time

frequency

1 resource block =

180 kHz = 12 subcarriers

1 slot = 0.5 ms =

7 SC-FDMA symbols**

1 subframe =

1 ms= 1 TTI*

LTE uplink SC-FDMA time-frequency multiplexing

*TTI = transmission time interval

** For normal cyclic prefix duration

Subcarrier spacing = 15 kHz

QPSK, 16QAM or 64QAM modulation

UE1

UE4

UE3 UE2

UE5 UE6


LTE Uplink: baseband signal generation

Avoid

constant

sequences

QPSK

16 QAM

64 QAM

(optional)

Discrete

Fourier

Transform

Mapping on

physical

Ressource,

i.e.

subcarriers

not used for

reference

signals

1 stream =

several

subcarriers,

based on

Physical

ressource

blocks

Modulation

mapper

Transform

precoderScrambling

SC-FDMA

signal gen.

Resource

element mapper

UE specific

Scrambling code


LTE evolution

LTE Rel. 9 features

LTE Advanced


CoMP

In-device

co-existence Diverse Data

Application

Relaying

eICIC

enhancements

eMBMS

enhancements

LTE Release 8

FDD / TDD

DL UL

DL UL

The LTE evolution

Rel-10

Relaying

SON

enhancements

Carrier

Aggregation

MIMO 8x8 MIMO 4x4 Enhanced

SC-FDMA

eICIC

Rel-9

Rel-11

eMBMS

Positioning

Dual Layer

Beamforming

Multi carrier /

Multi-RAT

Base Stations

Home eNodeB

Self Organizing

Networks

Public Warning

System


What are antenna ports?

l 3GPP TS 36.211(Downlink)

“An antenna port is defined such that the channel over which a symbol on the

antenna port is conveyed can be inferred from the channel over which another

symbol on the same antenna port is conveyed.”

l What does that mean?

l The UE shall demodulate a received signal – which is transmitted over a

certain antenna port – based on the channel estimation performed on the

reference signals belonging to this (same) antenna port.



l Consequences of the definition

l There is one sort of reference signal per antenna port

l Whenever a new sort of reference signal is introduced by 3GPP (e.g. PRS),

a new antenna port needs to be defined (e.g. Antenna Port 6)

l 3GPP defines the following antenna port / reference signal

combinations for downlink transmission:

l Port 0-3: Cell-specific Reference Signals (CS-RS)

l Port 4: MBSFN-RS

l Port 5: UE-specific Reference Signals (DM-RS): single layer (TX mode 7)

l Port 6: Positioning Reference Signals (PRS)

l Port 7-8: UE-specific Reference Signals (DM-RS): dual layer (TX mode 8)

l Port 7-14: UE specific Referene Signals for Rel. 10

l Port 15 – 22: CSI specific reference signals, channel status info in Rel. 10



l Mapping „Antenna Port“ to „Physical Antennas“

AP7

AP8

AP0

AP2

AP3

AP1

AP4

AP6

AP5

Antenna Port Physical Antennas

PA0

PA1

PA2

PA3

…

1

1

1

1

W5,0

W5,1

W5,2

W5,3

The way the "logical" antenna ports are mapped to the "physical" TX antennas lies

completely in the responsibility of the base station. There's no need for the base station

to tell the UE.

…

… …


LTE antenna port definition

Antenna ports are linked to the reference signals

-> one example:

Cell Specific RS

PA - RS

PCFICH / PHICH / PDCCH

Normal CP

PUSCH or No Transmission

UE in idle mode, scans for

Antenna port 0, cell specific RS

UE in connected mode, scans

Positioning RS on antenna port 6

to locate its position


Multimedia Broadcast Messaging Services, MBMS

Broadcast:

Public info for

everybody

Multicast:

Common info for

User after authentication

Unicast:

Private info for dedicated user


LTE MBMS architecture


MBMS in LTE

MBMS

GW

eNB

MCE

|

|

M1

M3 MBMS GW: MBMS Gateway

MCE: Multi-Cell/Multicast Coordination Entity

M1: user plane interface

M2: E-UTRAN internal control plane interface

M3: control plane interface between E-UTRAN and EPC

MME

|

M2

Logical architecture for MBMS


MBSFN – MBMS Single Frequency Network

Mobile communication network

each eNode B sends individual

signals

Single Frequency Network

each eNode B sends identical

signals


MBSFN

If network is synchronised,

Signals in downlink can be

combined


evolved Multimedia Broadcast Multicast Services Multimedia Broadcast Single Frequency Network (MBSFN) area

l Useful if a significant number of users want to consume the same data

content at the same time in the same area!

l Same content is transmitted in a specific area is known as MBSFN area.

l Each MBSFN area has an own identity (mbsfn-AreaId 0…255) and can consists of

multiple cells; a cell can belong to more than one MBSFN area.

l MBSFN areas do not change dynamically over time.

5

2

1

3

4

6

7

9

11

12

13

10

MBSFN area 0

14

A cell can belong to

more than one MBSFN

area; in total up to 8.

MBSFN area 1

13

8

MBSFN area 255

MBSFN reserved cell.

A cell within the MBSFN

area, that does not support

MBMS transmission.

15


eMBMS Downlink Channels

l Downlink channels related to MBMS

l MCCH Multicast Control Channel

l MTCH Multicast Traffic Channel

l MCH Multicast Channel

l PMCH Physical Multicast Channel

l MCH is transmitted over MBSFN in

specific subrames on physical layer

l MCH is a downlink only channel (no HARQ, no RLC repetitions)

l Higher Layer Forward Error Correction (see TS26.346)

l Different services (MTCHs and MCCH) can be multiplexed


eMBMS channel mapping

Subframes 0 and 5 are not MBMS, because

of PBCH and Sync Channels

Subframes 0,4,5 and 9 are not MBMS, because

Of paging occasion can occur here


eMBMS allocation based on SIB2 information

011010

Reminder:

Subframes

0,4,5, and 9

Are non-MBMS


eMBMS: MCCH position according to SIB13


LTE Release 9 Dual-layer beamforming

l 3GPP Rel-8 – Transmission Mode 7 = beamforming without

UE feedback, using UE-specific reference signal pattern,

l Estimate the position of the UE (Direction of Arrival, DoA),

l Pre-code digital baseband to direct beam at direction of arrival,

l BUT single-layer beamforming, only one codeword (TB),

l 3GPP Rel-9 – Transmission Mode 8 = beamforming with or

without UE feedback (PMI/RI) using UE-specific reference

signal pattern, but dual-layer,

l Mandatory for TDD, optional for FDD,

l 2 (new) reference signal pattern for two new antenna ports 7 and 8,

l New DCI format 2B to schedule transmission mode 8,

l Performance test in 3GPP TS 36.521 Part 1 (Rel-9) are adopted to

support testing of transmission mode 8.


LTE Release 9 Dual-layer beamforming – Reference Symbol Details

l Cell specific antenna port 0 and antenna port 1 reference symbols

Antenna Port 0 Antenna Port 1

Antenna Port 7 Antenna Port 8

l UE specific antenna

port 7 and antenna

port 8 reference

symbols


2 layer beamforming

Spatial multiplexing increases throughput, but looses coverage

throughput

coverage

Spatial multiplexing: increase throughput but less coverage

1 layer beamforming: increase coverage

SISO: coverage and throughput, no increase

2 layer beamforming

Increases throughput and

coverage


Location based services

l Location Based Services“

l Products and services which need location

information

l Future Trend:

Augmented Reality


Where is Waldo?


Location based services

The idea is not new, … so what to discuss?

Satellite based services

Network based services

Location

controller

Who will do the measurements? The UE or the network? = „assisted“

Who will do the calculation? The UE or the network? = „based“

So what is new?

Several ideas are defined and hybrid mode is possible as well,

Various methods can be combined.


E-UTRA supported positioning methods


Secure User Plane

SUPL= user plane

signaling

LCS

Server (LS)

SUPL / LPP

LPPa

E-UTRA supported positioning network architecture Control plane and user plane signaling

1) SLP – SUPL Location Platform, SUPL – Secure User Plane Location 2) E-SMLC – Evolved Serving Mobile Location Center 3) GMLC – Gateway Mobile Location Center 4) LCS – Location Service 5) 3GPP TS 36.455 LTE Positioning Protocol Annex (LPPa) 6) 3GPP TS 36.355 LTE Positioning Protocol (LPP)

LTE base station

eNodeB (eNB)

E-SMLC2)

SLP1)

Mobile

Management

Entity (MME)

Serving

Gateway

(S-GW)

Packet

Gateway

(P-GW)

SLs

S1-MME

S5

LTE-capable device

User Equipment, UE

(LCS Target)

S1-U Lup

LCS4)

Client

GMLC3)

LPP

SLs

Location positioning

protocol LPP =

control plane

signaling


E-UTRAN UE Positioning Architecture

l In contrast to GERAN and UTRAN, the E-UTRAN positioning

capabilities are intended to be forward compatible to other access

types (e.g. WLAN) and other positioning methods (e.g. RAT uplink

measurements).

l Supports user plane solutions, e.g. OMA SUPL 2.0

Source: 3GPP TS 36.305

UE = User Equipment

SUPL* = Secure User Plane Location

OMA* = Open Mobile Alliance

SET = SUPL enabled terminal

SLP = SUPL locaiton platform

E-SMLC = Evolved Serving Mobile

Location Center

MME = Mobility Management Entity

RAT = Radio Access Technology

*www.openmobilealliance.org/technical/release_program/supl_v2_0.aspx


http://www.hindawi.com/journals/ijno/2010/812945/

Global Navigation Satellite Systems

l GNSS – Global Navigation Satellite Systems; autonomous

systems:

l GPS – USA 1995.

l GLONASS – Russia, 2012.

l Gallileo – Europe, target 201?.

l Compass (Beidou) – China, under

development, target 2015.

l IRNSS – India, planning process.

l GNSS are designed for

continuous

reception, outdoors.

l Challenging environments:

urban, indoors, changing

locations.

GALLILEO GPS GLONASS

Signal fCarrier [MHz] Signal fCarrier [MHz] Signal fCarrier [MHz]

E1 1575,420 L1C/A 1575,420 G1 1602±k*0,562

5

E6 1278,750 L1C 1575,420 G2 1246±k*0,562

5

E5 1191,795 L2C 1227,600 k = -7 … 13

E5a 1176,450 L5 1176,450

E5b 1207,140

1164 1215 1237 1260 1300 1559 1591

1610 1587 1563

E5a

L5 L5b L2 G2

E1

L1 G1 E6

f [MHz]


LTE Positioning Protocol (LPP) 3GPP TS 36.355

UE E-SMLC

LPP over SUPL

User plane solution

LPP over RRC

Control plane solution

SET SLP

Target

Device LPP

Location

Server Assistance data

Measurements based on reference sources*

eNB

LTE radio

signal

LPP position methods - A-GNSS Assisted Global Navigation Satellite System

- E-CID Enhanced Cell ID

- OTDOA Observed time differerence of arrival

*GNSS and LTE radio signals

SUPL enabled

Terminal

SUPL location

platform

Enhanced Serving

Mobile Location Center


GNSS positioning methods supported l Autonomeous GNSS

l Assisted GNSS (A-GNSS)

l The network assists the UE GNSS receiver to

improve the performance in several aspects:

– Reduce UE GNSS start-up and acquisition times

– Increase UE GNSS sensitivity

– Allow UE to consume less handset power

l UE Assisted

– UE transmits GNSS measurement results to E-SMLC where the position calculation

takes place

l UE Based

– UE performs GNSS measurements and position calculation, suppported by data …

– … assisting the measurements, e.g. with reference time, visible satellite list etc.

– … providing means for position calculation, e.g. reference position, satellite ephemeris, etc.

Source: 3GPP TS 36.305


E1

GNSS band allocations

L5 E5b L2 G2 E6 L1 G1 1164 1215 1260 1300 1559 1610

E5a

1237 1591 1563 1587

f/MHz


GPS and GLONASS satellite orbits

GPS:

26 Satellites

Orbital radius 26560 km

GLONASS:

26 Satellites

Orbital radius 25510 km


Why is GNSS not sufficent?

l Global navigation satellite systems (GNSSs) have restricted

performance in certain environments

l Often less than four satellites visible: critical situation for GNSS

positioning

support required (Assisted GNSS)

alternative required (Mobile radio positioning)

Critical scenario Very critical scenario GPS Satellites visibility (Urban)

Reference [DLR]


(A-)GNSS vs. mobile radio positioning methods

(A-)GNSS Mobile radio systems

Low bandwidth (1-2 MHz) High bandwidth (up to 20 MHz for LTE)

Very weak received signals Comparatively strong received signals

Similar received power levels from all satellites One strong signal from the serving BS,

strong interference situation

Long synchronization sequences Short synchronization sequences

Signal a-priori known due to low data rates Complete signal not a-priori known to

support high data rates, only certain pilots

Very accurate synchronization of the satellites

by atomic clocks Synchronization of the BSs not a-priori guaranteed

Line of sight (LOS) access as normal case

not suitable for urban / indoor areas

Non line of sight (NLOS) access as normal case

suitable for urban / indoor areas

3-dimensional positioning 2-dimensional positioning


Measurements for positioning

l UE-assisted measurements.

l Reference Signal Received

Power

(RSRP) and Reference Signal

Received Quality (RSRQ).

l RSTD – Reference Signal Time

Difference.

l UE Rx–Tx time difference.

l eNB-assisted measurements.

l eNB Rx – Tx time difference.

l TADV – Timing Advance.

– For positioning Type 1 is of

relevance.

l AoA – Angle of Arrival.

l UTDOA – Uplink Time Difference

of Arrival.

RSRP, RSRQ are

measured on reference

signals of serving cell i

Serving cell i

Neighbor cell j

RSTD – Relative time difference

between a subframe received from

neighbor cell j and corresponding

subframe from serving cell i:

TSubframeRxj - TSubframeRxi

Source: see TS 36.214 Physical Layer measurements for detailed definitions

UE Rx-Tx time difference is defined

as TUE-RX – TUE-TX, where TUE-RX is the

received timing of downlink radio frame

#i from the serving cell i and TUE-TX the

transmit timing of uplink radio frame #i.

DL radio frame #i

UL radio frame #i

eNB Rx-Tx time difference is defined

as TeNB-RX – TeNB-TX, where TeNB-RX is the

received timing of uplink radio frame #i

and TeNB-TX the transmit timing of

downlink radio frame #i.

UL radio frame #i DL radio frame #i

TADV (Timing Advance)

= eNB Rx-Tx time difference + UE Rx-Tx time difference

= (TeNB-RX – TeNB-TX) + (TUE-RX – TUE-TX)


Observed Time difference

If network is synchronised,

UE can measure time difference

Observed Time

Difference of Arrival

OTDOA


Methods‘ overview CID E-CID (RSRP/TOA/TADV) E-CID (RSRP/TOA/TADV) [Trilateration]

E-CID (AOA) [Triangulation] Downlink / Uplink (O/U-TDOA) [Multilateration] RF Pattern matching

To be updated!!


Cell ID

l Not new, other definition: Cell of Origin (COO).

l UE position is estimated with the knowledge of the geographical

coordinates of its serving eNB.

l Position accuracy = One whole cell .


Enhanced-Cell ID (E-CID)

l UE positioning compared to CID is specified more

accurately using additional UE and/or E UTRAN radio

measurements:

l E-CID with distance from serving eNB position accuracy: a circle.

– Distance calculated by measuring RSRP / TOA / TADV (RTT).

l E-CID with distances from 3 eNB-s position accuracy: a point.

– Distance calculated by measuring RSRP / TOA / TADV (RTT).

l E-CID with Angels of Arrival position accuracy: a point.

– AOA are measured for at least 2, better 3 eNB‘s.

RSRP – Reference Signal Received Power

TOA – Time of Arrival

TADV – Timing Advance

RTT – Round Trip Time


Angle of Arrival (AOA)

l AoA = Estimated angle of a UE with respect to a reference

direction (= geographical North), positive in a counter-

clockwise direction, as seen from an eNB.

l Determined at eNB antenna based

on a received UL signal (SRS).

l Measurement at eNB:

l eNB uses antenna array to estimate

direction i.e. Angle of Arrival (AOA).

l The larger the array, the more

accurate is the estimated AOA.

l eNB reports AOA to LS.

l Advantage: No synchronization

between eNB‘s.

l Drawback: costly antenna arrays.


OTDOA – Observed Time Difference of Arrival

l UE position is estimated based on measuring TDOA of

Positioning Reference Signals (PRS) embedded into overall

DL signal received from different eNB’s.

l Each TDOA measurement describes a hyperbola (line of constant

difference 2a), the two focus points of which (F1, F2) are the two

measured eNB-s (PRS sources), and along which the UE may be

located.

l UE’s position = intersection of hyperbolas for at least 3 pairs of

eNB’s.


Positioning Reference Signals (PRS) for OTDOA Definition

l Cell-specific reference signals (CRS) are not sufficient for

positioning, introduction of positioning reference signals

(PRS) for antenna port 6.

l SINR for synchronization

and reference signals of

neighboring cells needs to

be at least -6 dB.

l PRS is a pseudo-random

QPSK sequence similar

to CRS; PRS pattern:

l Diagonal pattern with time

varying frequency shift.

l PRS mapped around CRS to avoid collisions;

never overlaps with PDCCH; example shows

CRS mapping for usage of 4 antenna ports.


Uplink (UTDOA)

l UTDOA = Uplink Time Difference of Arrival

l UE positioning estimated based on:

– measuring TDOA of UL (SRS) signals received in different eNB-s

– each TDOA measurement describes a hyperbola (line of constant difference 2a), the 2 focus points of which (F1, F2) are the two receiving eNB-s (SRS receiptors), and along which the UE may be located.

– UE’s position = intersection of hyperbolas for at least three pairs of eNB-s (= 3 eNB-s)

– knowledge of the geographical coordinates of the measured eNode Bs

l Method as such not specified for LTE Similarity to 3G assumed

Location

Server

- eNB-s measure and

report to eNB_Rx-Tx to LS

-LS calculates UTDOA

and estimates the UE

position


IMT-Advanced Requirements

l A high degree of commonality of functionality worldwide while

retaining the flexibility to support a wide range of services and

applications in a cost efficient manner,

l Compatibility of services within IMT and with fixed networks,

l Capability of interworking with other radio access systems,

l High quality mobile services,

l User equipment suitable for worldwide use,

l User-friendly applications, services and equipment,

l Worldwide roaming capability; and

l Enhanced peak data rates to support advanced services and

applications,

l 100 Mbit/s for high and

l 1 Gbit/s for low mobility

were established as targets for research,


Do you Remember? Targets of ITU IMT-2000 Program (1998)

IMT-2000 The ITU vision of global wireless access

in the 21st century

Satellite

MacrocellMicrocell

UrbanIn-Building

Picocell

Global

Suburban

Basic Terminal

PDA Terminal

Audio/Visual Terminal

l Flexible and global – Full coverage and mobility at 144 kbps .. 384 kbps

– Hot spot coverage with limited mobility at 2 Mbps

– Terrestrial based radio access technologies

l The IMT-2000 family of standards now supports four different multiple

access technologies:

l FDMA, TDMA, CDMA (WCDMA) and OFDMA (since 2007)


IMT Spectrum

Next possible spectrum

allocation at WRC 2015!

MHz

MHz

MHz

MHz


Expected IMT-Advanced candidates

Source: TTA‘s workshop for the future of IMT-Advanced technologies, June 2008

Long

Term

Evolution

Ultra

Mobile

Broadband

Advanced

Mobile

WiMAX


IMT – International Mobile Communication

l IMT-2000

l Was the framework for the third Generation mobile communication

systems, i.e. 3GPP-UMTS and 3GPP2-C2K

l Focus was on high performance transmission schemes:

Link Level Efficiency

l Originally created to harmonize 3G mobile systems and to increase

opportunities for worldwide interoperability, the IMT-2000 family of

standards now supports four different access technologies, including

OFDMA (WiMAX), FDMA, TDMA and CDMA (WCDMA).

l IMT-Advanced

l Basis of (really) broadband mobile communication

l Focus on System Level Efficiency (e.g. cognitive network

systems)

l Vision 2010 – 2015


LTE-Advanced Possible technology features

Cognitive radio

methods

Enhanced MIMO

schemes for DL and UL

Interference management

methods

Relaying

technology

Cooperative

base stations

Radio network evolution

Further enhanced

MBMS

Wider bandwidth

support


Bandwidth extension with Carrier aggregation


LTE-Advanced Carrier Aggregation

Contiguous carrier aggregation

Non-contiguous carrier aggregation

Component carrier CC


Aggregation

l Contiguous

l Intra-Band

l Non-Contiguous

l Intra (Single) -Band

l Inter (Multi) -Band

l Combination

l Up to 5 Rel-8 CC and 100 MHz

l Theoretically all CC-BW combinations possible (e.g. 5+10+20 etc)


l Two or more component carriers are aggregated in LTE-Advanced

in order to support wider bandwidths up to 100 MHz.

l Support for contiguous and non-

contiguous component carrier

aggregation (intra-band) and

inter-band carrier aggregation. l Different bandwidths per

component carrier (CC) are possible.

l Each CC limited to a max. of 110 RB

using the 3GPP Rel-8 numerology

(max. 5 carriers, 20 MHz each).

l Motivation.

l Higher peak data rates to meet

IMT-Advanced requirements.

l NW operators: spectrum aggregation, enabling Heterogonous Networks.

Carrier aggregation (CA) General comments

Frequency band A Frequency band B



Intra-band contiguous

Intra-band non-contiguous

Inter-band

Component

Carrier (CC)

2012 © by Rohde&Schwarz


Overview l Carrier Aggregation (CA)

enables to aggregate up to 5 different cells (component carriers CC), so that a maximum system bandwidth of 100 MHz can be supported (LTE-Advanced requirement).

l Each CC = Rel-8 autonomous cell

– Backwards compatibility

l CC-Set is UE specific

– Registration Primary (P)CC

– Additional BW Secondary (S)CC-s 1-4

l Network perspective

– Same single RLC-connection for one UE (independent on the CC-s)

– Many CC (starting at MAC scheduler) operating the UE

l For TDD

– Same UL/DL configuration for all CC-s

UE1 U3

UE3

UE2

UE4

UE1

UE4 UE3 UE4 U2

CC1 CC2

CC1 CC2

Cell 1 Cell 2


Carrier aggregation (CA) General comments, cont’d. l A device capable of carrier aggregation has 1 DL primary component

carrier and 1 associated primary UL component carrier.

l Basic linkage between DL and UL is signaled in SIB Type 2.

l Configuration of primary component carrier (PCC) is UE-specific.

– Downlink: cell search / selection, system information, measurement and

mobility.

– Uplink: access procedure on PCC, control information (PUCCH) on PCC.

– Network may decide to switch PCC for a device handover procedure is

used.

l Device may have one or several secondary component carriers. Secondary

Component Carriers (SCC) added in RRC_CONNECTED mode only.

– Symmetric carrier aggregation.

– Asymmetric carrier aggregation (= Rel-10).

SCC PCC PCC SCC

Downlink Uplink

SCC SCC SCC SCC SCC SCC

PDSCH, PDCCH is optional

PDSCH and PDCCH

PUSCH only

PUSCH and PUCCH

2012 © by Rohde&Schwarz


LTE-Advanced Carrier Aggregation – Initial Deployment

l Initial LTE-Advanced deployments will likely be limited to

the use of two component carrier.

l The below are focus scenarios identified by 3GPP RAN4.


Bandwidth

l General

– Up to 5 CC

– Up to 100 RB-s pro CC

– Up to 500 RB-s aggregated

l Aggregated transmission

bandwidth

– Sum of aggregated channel

bandwidths

– Illustration for Intra band

contiguous

– Channel raster 300 kHz

l Bandwidth classes

– UE Capability

MHz3.06.0

1.0 spacingchannelNominal

)2()1()2()1(

ChannelChannelChannelChannel BWBWBWBW


Bands / Band-Combinations (II) l Under discussion

l 25 WI-s in RAN4 with

practical interest

– Inter band (1 UL CC)

– Intra band cont (1 UL CC)

– Intra band non cont

(1 UL CC)

– Inter band (2 UL CC)

l Release independency

l Band performance is

release independent

– Band introduced in Rel-11

– Performance tested for Rel-

10


Carrier aggregation - configurations

l CA Configurations

l E-UTRA CA Band + Allowed BW = CA Configuration

– Intra band contiguous

– Most requirements

– Inter band

– Some requirements

– Main interest of many companies

– Intra band non contiguous

– No configuration / requirements

– Feature of later releases?

l CA Requirement applicability – CL_X Intra band CA

– CL_X-Y Inter band

– Non-CA no CA (explicitely stated for the Test point which are tested differently for CA and not CA)


UE categories for Rel-10 NEW! UE categories 6…8 (DL and UL)

UE

Category

Maximum number

of DL-SCH transport

block bits received

within a TTI

Maximum number of bits

of a DL-SCH transport

block received within a TTI

Total number of

soft channel bits

Maximum number of

supported layers for

spatial multiplexing in DL

… … … … …

Category 6 301504 149776 (4 layers)

75376 (2 layers) 3654144 2 or 4

Category 7 301504 149776 (4 layers)

75376 (2 layers) 3654144 2 or 4

Category 8 2998560 299856 35982720 8

~3 Gbps peak

DL data rate

for 8x8 MIMO UE

Category

Maximum number

of UL-SCH

transport

block bits

transmitted

within a TTI

Maximum number

of bits of an UL-SCH

transport block

transmitted within a

TTI

Support

for

64Q

AM

in UL

… … … …

Category 6 51024 51024 No

Category 7 102048 51024 No

Category 8 1497760 149776 Yes

Total layer 2

buffer size

[bytes]

…

3 300 000

3 800 000

42 200 000

~1.5 Gbps peak

UL data rate, 4x4 MIMO


Deployment scenarios

F1 F2

3) Improve coverage

l #1: Contiguous frequency aggregation – Co-located & Same coverage

– Same f

l #2: Discontiguous frequency aggregation – Co-located & Similar coverage

– Different f

l #3: Discontiguous frequency aggregation – Co-Located & Different coverage

– Different f

– Antenna direction for CC2 to cover blank spots

l #4: Remote radio heads – Not co-located

– Intelligence in central eNB, radio heads = only transmission antennas

– Cover spots with more traffic

– Is the transmission of each radio head within the cell the same?

l #5:Frequency-selective repeaters – Combination #2 & #4

– Different f

– Extend the coverage of the 2nd CC with Relays


Physical channel arrangement in downlink

Each component

carrier transmits P-

SCH and S-SCH,

Like Rel.8

Each component

carrier transmits

PBCH,

Like Rel.8


LTE-Advanced Carrier Aggregation – Scheduling

Non-Contiguous spectrum allocation Contiguous spectrum allocation

Data mod.

Mapping

Channel coding

HARQ

Data mod.

Mapping

Channel coding

HARQ

Data mod.

Mapping

Channel coding

HARQ

Data mod.

Mapping

Channel coding

HARQ

Dynamic

switching

RLC transmission buffer

[frequency in MHz]

e.g. 20 MHz

Each component

Carrier may use its

own AMC,

= modulation + coding

scheme


Carrier Aggregation – Architecture downlink

HARQ HARQ

DL-SCH

on CC1

...

Segm.

ARQ etc

Multiplexing UE1 Multiplexing UEn

BCCH PCCH

Unicast Scheduling / Priority Handling

Logical Channels

MAC

Radio Bearers

Security Security...

CCCH

MCCH

Multiplexing

MTCH

MBMS Scheduling

PCHBCH MCH

RLC

PDCP

ROHC ROHC...

Segm.

ARQ etc...

Transport Channels

Segm.

ARQ etc

Security Security...

ROHC ROHC...

Segm.

ARQ etc...

Segm. Segm.

...

...

...

DL-SCH

on CCx

HARQ HARQ

DL-SCH

on CC1

...

DL-SCH

on CCy

In case of CA, the multi-carrier nature of the physical layer is only exposed

to the MAC layer for which one HARQ entity is required per serving cell

Multiplexing

...

Scheduling / Priority Handling

Transport Channels

MAC

RLC

PDCP

Segm.

ARQ etc

Segm.

ARQ etc

Logical Channels

ROHC ROHC

Radio Bearers

Security Security

CCCH

HARQ HARQ

UL-SCH

on CC1

...

UL-SCH

on CCz

1 UE using carrier aggregation


Common or separate PDCCH per Component Carrier?

No cross-carrier

scheduling

Time

Fre

qu

en

cy

PD

CC

H

PD

CC

H

PD

CC

H PDSCH

PDSCH

PDSCH

up to 3 (4) symbols

per subframe

PD

CC

H

Cross-carrier

scheduling

1 subframe = 1 ms

PD

CC

H

PD

CC

H

1 slot = 0.5 ms

PDSCH

PDSCH

PDSCH

l No cross-carrier scheduling.

l PDCCH on a component carrier

assigns PDSCH resources on the

same component carrier (and

PUSCH resources on a single

linked UL component carrier).

l Reuse of Rel-8 PDCCH structure

(same coding, same CCE-based

resource mapping) and DCI formats.

l Cross-carrier scheduling.

l PDCCH on a component carrier

can assign PDSCH or PUSCH

resources in one of multiple component

carriers using the carrier indicator field.

l Rel-8 DCI formats extended with

3 bit carrier indicator field.

l Reusing Rel-8 PDCCH structure (same

coding, same CCE-based resource

mapping).

PC

C


Carrier aggregation: control signals + scheduling

Each CC has

its own control

channels,

like Rel.8

Femto cells:

Risk of interference!

-> main component

carrier will send

all control information.


DCI control elements: CIF field

Carrier Indicator Field, CIF, 3bits

f f f

New field: carrier indicator field gives information,

which component carrier is valid.

=> reminder: maximum 5 component carriers!

Component carrier 1 Component carrier 2 Component carrier N


PDSCH start field

R

R

R

PCFICH PCFICH PCFICH

Example: 1 Resource block

Of a component carrier

e.g. PCC

Primary component

carrier PDSCH start

field indicates

position

In cross-carrier scheduling,the UE does not read the PCFICH

andPDCCH on SCC, thus it has to know the start of the

PDSCH

PDCCH e.g. SCC

Secondary component

carrier


Component Carrier – RACH configuration

Asymmetric carrier

Aggregation possible,

e.g. DL more CC than UL

Downlink

Uplink

Each CC has its own RACH All CC use same RACH preamble

Network responds on all CCs

Only 1 CC contains RACH


Carrier Aggregation

l The transmission mode is not constrained to be the same

on all CCs scheduled for a UE

l A single UE-specific UL CC is configured semi-statically for

carrying PUCCH A/N, SR, and periodic CSI from a UE

l Frequency hopping is not supported simultaneously with

non-contiguous PUSCH resource allocation

l UCI cannot be carried on more than one PUSCH in a given

subframe.


Carrier Aggregation

l Working assumption is confirmed that a single set of PHICH

resources is shared by all UEs (Rel-8 to Rel-10)

l If simultaneous PUCCH+PUSCH is configured and there is

at least one PUSCH transmission

l UCI can be transmitted on either PUCCH or PUSCH with a

dependency on the situation that needs to be further discussed

l All UCI mapped onto PUSCH in a given subframe gets mapped onto

a single CC irrespective of the number of PUSCH CCs


UE Architectures

l Possible TX architectures

l Same / Different antenna (connectors) for each CC

l D1/D2 could be switched to support CA or UL MIMO


LTE–Advanced solutions from R&S R&S® SMU200 Vector Signal Generator


Ref -20 dBm Att 5 dB

RBW 2 MHz

VBW 5 MHz

SWT 2.5 ms

Center 2.17 GHz Span 100 MHz10 MHz/

1 AP

CLRWR

A

3DB

EXT

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

Date: 8.OCT.2009 14:13:24

LTE–Advanced solutions from R&S R&S® FSQ Signal Analyzer

LTE-Advanced – An introduction

A. Roessler | October 2009 | 157

20 MHz

E-UTRA carrier 2 fc,E-UTRA carrier 2 = 2205 MHz

-10 dB

20 MHz

E-UTRA carrier 2 fc,E-UTRA carrier 2 = 2135 MHz


Enhanced MIMO schemes

l Increased number of layers:

l Up to 8x8 MIMO in downlink.

l Up to 4x4 MIMO in uplink.

l In addition the downlink reference signal structure has been

enhanced compared with LTE Release 8 by:

l Demodulation Reference signals (DM-RS) targeting PDSCH demodulation.

– UE specific, i.e. an extension to multiple layers of the concept of Release 8 UE-

specific reference signals used for beamforming.

l Reference signals targeting channel state information (CSI-RS) estimation

for CQI/PMI/RI/etc reporting when needed.

– Cell specific, sparse in the frequency and time domain and punctured into the data

region of normal subframes.


Cell specific Reference Signals vs. DM-RS

l Demodulation-Reference signals DM-RS and data are precoded

the same way, enabling non-codebook based precoding and

enhanced multi-user beamforming.

LTE Rel.8 LTE-Advanced (Rel.10)

s1

s2

sN

........

Pre-

coding

s1

s2

sN

........

Pre-

coding

Cell specific

Reference signalsN

CRS0

DM-RSN

DM-RS0

Cell specific

reference signalsN +

Channel status information

reference signals 0

CRS0 + CSI-RS0


Ref. signal mapping: Rel.8 vs. LTE-Advanced

l Example:

l 2 antenna ports, antenna port 0,

CSI-RS configuration 8.

l PDCCH (control) allocated in the

first 2 OFDM symbols.

l CRS sent on all RBs; DTX sent

for the CRS of 2nd antenna

port.

l DM-RS sent only for scheduled

RBs on all antennas; each set

coded differently between the

two layers.

l CSI-RS punctures Rel. 8 data;

sent periodically over allotted

REs (not more than twice per

frame)

LTE (Release 8) LTE-A (Release 10)0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6

0

x x x x 1E

x x x x SA

E

x x x x LE

R

x x x x

8

x x x x

Ex x x x S

AE

x x x x LE

R

x x x x

PDSCH PDCCH CRS DM-RS CSI-RS


DL MIMO Extension up to 8x8

l Max number of transport blocks: 2

l Number of MCS fields

l one for each transport block

l ACK/NACK feedback

l 1 bit per transport block for evaluation

as a baseline

l Closed-loop precoding supported

l Rely on precoded dedicated

demodulation RS (decision on DL RS)

l Conclusion on the codeword-to-

layer mapping:

l DL spatial multiplexing of up to eight

layers is considered for LTE-Advanced,

l Up to 4 layers, reuse LTE codeword-to-

layer mapping,

l Above 4 layers mapping – see table

l Discussion on control signaling

details ongoing

Codeword to layer mapping for spatial multiplexing

Number

of layers

Number

of code

words

Codeword-to-layer mapping

5 2

6 2

7 2

8 2

110 layer

symbM,,i

)34()(

)24()(

)14()(

)4()(

)1()7(

)1()6(

)1()5(

)1()4(

idix

idix

idix

idix

)34()(

)24()(

)14()(

)4()(

)0()3(

)0()2(

)0()1(

)0()0(

idix

idix

idix

idix

)34()(

)24()(

)14()(

)4()(

)1()6(

)1()5(

)1()4(

)1()3(

idix

idix

idix

idix

)23()(

)13()(

)3()(

)0()2(

)0()1(

)0()0(

idix

idix

idix

)23()(

)13()(

)3()(

)1()5(

)1()4(

)1()3(

idix

idix

idix

)23()(

)13()(

)3()(

)0()2(

)0()1(

)0()0(

idix

idix

idix

)23()(

)13()(

)3()(

)1()4(

)1()3(

)1()2(

idix

idix

idix

)12()(

)2()()0()1(

)0()0(

idix

idix

32 )1(

symb

)0(

symb

layer

symb MMM

33 )1(

symb

)0(

symb

layer

symb MMM

43 )1(

symb

)0(

symb

layer

symb MMM

44 )1(

symb

)0(

symb

layer

symb MMM


MIMO – layer and codeword

Codeword 1:

111000011101

Codeword 2:

010101010011

1 0 1

1 0 1

0 1 1

1 0 0

0 0 0

1 1 1

1 1 1

0 0 1

Codeword 1:

111000011101

Codeword 2:

010101010011

ACK ACK

ACK

Up to 8 times

the data ->

8 layers

Receiver only

Sends

2 ACK/NACKs


Uplink MIMO Extension up to 4x4 l Rel-8 LTE.

l UEs must have 2 antennas for reception.

l But only 1 amplifier for transmission is available (costs/complexity).

l UL MIMO only as antenna switching mode (switched diversity).

l 4x4 UL SU-MIMO is needed to fulfill peak data rate requirement of

15 bps/Hz.

l Schemes are very similar to DL MIMO modes.

l UL spatial multiplexing of up to 4 layers is considered for LTE-Advanced.

l SRS enables link and SU-MIMO adaptation.

l Number of receive antennas are receiver-implementation

specific.

l At least two receive antennas is assumed on the terminal side.


UL MIMO – signal generation in uplink

ScramblingModulation

mapper

Layer

mapperPrecoding

Resource element

mapper

SC-FDMA

signal gen.

Resource element

mapper

SC-FDMA

signal gen.Scrambling

Modulation

mapper

layerscodewords

Transform

precoder

Transform

precoder

antenna ports

Similar to Rel.8 Downlink:

Avoid

periodic bit

sequence QPSK

16-QAM

64-QAM

Up to

4 layer

DFT,

as in Rel 8,

but non-

contiguous

allocation possible


LTE-Advanced Enhanced uplink SC-FDMA

l The uplink

transmission

scheme remains

SC-FDMA.

l The transmission of

the physical uplink

shared channel

(PUSCH) uses DFT

precoding.

l Two enhancements:

l Control-data

decoupling

l Non-contiguous

data transmission


Physical channel arrangement - uplink

Simultaneous transmission of

PUCCH and PUSCH from

the same UE is supported

Clustered-DFTS-OFDM

= Clustered DFT spread

OFDM.

Non-contiguous resource block allocation => will cause higher

Crest factor at UE side


LTE-Advanced Enhanced uplink SC-FDMA

Due to distribution we get active subcarriers beside

non-active subcarriers: worse peak to average ratio,

e.g. Crest factor


What are the effects of “Enhanced SC-FDMA”?

Source: http://www.3gpp.org/ftp/tsg_ran/WG4_Radio/TSGR4_54/Documents/R4-101056.zip


f [MHz]

Simultaneous PUSCH-PUCCH transmission, multi-cluster transmission l Remember, only one UL carrier in 3GPP Release 10;

scenarios:

l Feature support is indicated by PhyLayerParameters-v1020 IE*).

PUCCH PUSCH

PUCCH and

allocated PUSCH

PUCCH and fully

allocated PUSCH

PUCCH and partially

allocated PUSCH

partially

allocated PUSCH

f [MHz]

f [MHz] f [MHz]

*) see 3GPP TS 36.331 RRC Protocol Specification


Benefit of localized or distributed mode „static UE“: frequency selectivity is not time variant -> localized allocation

„high velocity UE“: frequency selectivity is time variant -> distributed allocation

Multipath causes frequency

Selective channel,

It can be time variant or

Non-time variant


Significant step towards 4G: Relaying ?



Radio Relaying approach


No Improvement of SNR resp. CINR


L1/L2 Relaying approach



Present Thrust- Spectrum Efficiency

l FCC Measurements:- Temporal and geographical variations in the utilization of the assigned spectrum range from 15% to 85%.

Momentary snapshot of frequency spectrum allocation

Why not use this

part of the spectrum?


ODMA – some ideas…

BTS

Mobile devices behave as

relay station

ODMA = opportunity driven multiple access


Cooperative communication

How to implement antenna arrays in mobile handsets?

Each mobile

is user and relay 3 principles of aid:

•Amplify and forward

•Decode and forward

•Coded cooperation

Multi-access

Independent

fading paths


Cooperative communication

Higher signaling

System complexity

Cell edge coverage

Group mobility

Multi-access

Independent

fading paths

Virtual

Antenna

Array

LTE, UMTS Long Term Evolution LTE measurements – from RF to application testing

Reiner Stuhlfauth

[email protected]

Training Centre

Rohde & Schwarz, Germany

Subject to change – Data without tolerance limits is not binding.

R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG. Trade names are trademarks

of the owners.

2011 ROHDE & SCHWARZ GmbH & Co. KG

Test & Measurement Division

- Training Center -

This folder may be taken outside ROHDE & SCHWARZ facilities.

ROHDE & SCHWARZ GmbH reserves the copy right to all of any part of these course notes.

Permission to produce, publish or copy sections or pages of these notes or to translate them must first

be obtained in writing from

ROHDE & SCHWARZ GmbH & Co. KG, Training Center, Mühldorfstr. 15, 81671 Munich, Germany


Mobile Communications: Fields for testing

l RF testing for mobile stations and user equipment

l RF testing for base stations

l Drive test solutions and verification of network

planning

l Protocol testing, signaling behaviour

l Testing of data end to end applications

l Audio and video quality testing

l Spectrum and EMC testing


Test Architecture RF-/L3-/IP Application-Test


LTE measurements general aspects


LTE RF Testing Aspects UE requirements according to 3GPP TS 36.521 Power

Maximum output power

Maximum power reduction

Additional Maximum Power

Reduction

Minimum output power

Configured Output Power

Power Control

Absolution Power Control

Relative Power Control

Aggregate Power Control

ON/OFF Power time mask

Output RF spectrum emissions

Occupied bandwidth

Out of band emissions

Spectrum emisssion mask

Additional Spectrum emission mask

Adjacent Channel Leakage Ratio

Transmit Intermodulation 36.521: User Equipment (UE) radio

transmission and reception

Transmit signal quality

Frequency error

Modulation quality, EVM

Carrier Leakage

In-Band Emission for non allocated RB

EVM equalizer spectrum flatness


LTE RF Testing Aspects UE requirements according to 3GPP, cont.

Receiver characteristics: Reference sensitivity level

Maximum input level

Adjacent channel selectivity

Blocking characteristics

In-band Blocking

Out of band Blocking

Narrow Band Blocking

Spurious response

Intermodulation characteristics

Spurious emissions

Performance


LTE bands and channel bandwidth E-UTRA band / channel bandwidth

E-UTRA Band 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz

1 Yes Yes Yes Yes

2 Yes Yes Yes Yes Yes[1] Yes[1]

3 Yes Yes Yes Yes Yes[1] Yes[1]

4 Yes Yes Yes Yes Yes Yes

5 Yes Yes Yes Yes[1]

6 Yes Yes[1]



9 Yes Yes Yes[1] Yes[1]

10 Yes Yes Yes Yes

11 Yes Yes[1]

12 Yes Yes Yes[1] Yes[1]

13 Yes[1] Yes[1]

14 Yes[1] Yes[1]

...

17 Yes[1] Yes[1]

...

33 Yes Yes Yes Yes

34 Yes Yes Yes



37 Yes Yes Yes Yes

38 Yes Yes Yes Yes

39 Yes Yes Yes Yes

40 Yes Yes Yes Yes

NOTE 1: bandwidth for which a relaxation of the specified UE receiver sensitivity requirement (Clause 7.3) is allowed.

Not every channel

bandwidth for

every band!


Tests performed at “low, mid and highest frequency”

lowest EARFCN possible

and 1 RB at position 0

RF p

ow

er

Frequency = whole LTE band

RF p

ow

er

Frequency

RF p

ow

er

Frequency

mid EARFCN

and 1 RB at position 0

Highest EARFCN

and 1 RB at max position

Nominal frequency described by EARFCN (E-UTRA Absolute Radio Frequency Channel Number)


LTE RF measurements on user equipment UEs


LTE Transmitter Measurements 1 Transmit power

1.1 UE Maximum Output Power

1.2 Maximum Power Reduction (MPR)

1.3 Additional Maximum Power Reduction (A-MPR)

1.4 Configured UE transmitted Output Power

2 Output Power Dynamics

2.1 Minimum Output Power

2.2 Transmit OFF power

2.3 ON/OFF time mask

2.3.1 General ON/OFF time mask

2.3.2 PRACH time mask

2.3.3 SRS time mask

2.4 Power Control

2.4.1 Power Control Absolute power tolerance

2.4.2 Power Control Relative power tolerance

2.4.3 Aggregate power control tolerance

3 Transmit signal quality

3.1 Frequency Error

3.2 Transmit modulation

3.2.1 Error Vector Magnitude (EVM)

3.2.2 Carrier leakage

3.2.3 In-band emissions for non allocated RB

3.2.4 EVM equalizer spectrum flatness

4 Output RF spectrum emissions

4.1 Occupied bandwidth

4.2 Out of band emission

4.2.1 Spectrum Emission Mask

4.2.2 Additional Spectrum Emission Mask

4.2.3 Adjacent Channel Leakage power Ratio

4.3 Spurious emissions

4.3.1 Transmitter Spurious emissions

4.3.2 Spurious emission band UE co-existence

4.3.3 Additional spurious emissions

5 Transmit intermodulation


UE Signal quality – symbolic structure of mobile radio tester MRT

RF correction FFT

TxRx

equalizer EVM meas. IDFT

Test equipment

Rx

…

…

…

…

…

…

Inband-

emmissions

l Carrier Frequency error

l EVM (Error Vector Magnitude)

l Origin offset + IQ offset

l Unwanted emissions, falling into non allocated resource blocks.

l Inband transmission

l Spectrum flatness

DUT


UL Power Control: Overview

UL-Power Control is a

combination of:

l Open-loop:

UE estimates the DL-Path-

loss and compensates it

for the UL

l Closed-loop:

in addition, the eNB

controls directly the UL-

Power through power-

control commands

transmitted on the DL


PUSCH power control

l Power level [dBm] of PUSCH is calculated every subframe i based on the following

formula out of TS 36.213

Dynamic offset (closed loop) Basic open-loop starting point

Maximum allowed UE power

in this particular cell,

but at maximum +23 dBm1)

Number of allocated

resource blocks (RB)

Combination of cell- and UE-specific

components configured by L3

Cell-specific

parameter

configured by L3

PUSCH transport

format

Transmit power for PUSCH

in subframe i in dBm

Power control

adjustment derived

from TPC command

received in subframe (i-4)

Downlink

path loss

estimate

Bandwidth factor

1) +23 dBm is maximum allowed power in LTE according to TS 36.101, corresponding to power class 3bis in WCDMA

MPR


LTE RF Testing: UE Maximum Power

UE transmits

with 23dBm ±2 dB

QPSK modulation is used. All channel bandwidths are

tested separately. Max power is for all band classes

Test is performed for varios uplink allocations


Resource Blocks number and maximum RF power

One active resource block

(RB) provides maximum

absolute RF power RF p

ow

er

Frequency

RF p

ow

er

Frequency

More RB’s in use will be at

lower RF power in order to

create same integrated

power

1 active resource block (RB),

Nominal band width 10 MHz = 50 RB’s

RF p

ow

er

Frequency

Additionally, MPR (Max.

Power Reduction) and A-

MPR are defined MPR


UE maximum power

FUL_low FUL_high

PPowerClass + 2dB

PPowerClass - 2dB

maximum output

power for any

transmission bandwidth

within the channel bandwidth

23dBm


UE maximum power – careful at band edge!

FUL_low FUL_high

PPowerClass + 2dB

PPowerClass - 2dB

23dBm

FUL_high- 4MHz FUL_low+4MHz

For transmission bandwidths confined within FUL_low and FUL_low + 4 MHz or

FUL_high – 4 MHz and FUL_high, the maximum output power requirement is relaxed

by reducing the lower tolerance limit by 1.5 dB

-1.5dB -1.5dB


LTE RF Testing: UE Minimum Power

UE transmits

with -40dBm

All channel bandwidths are tested separately.

Minimum power is for all band classes < -39 dBm


LTE RF Testing: UE Off Power

The transmit OFF power is defined as the mean power in a duration of at least one

sub-frame (1ms) excluding any transient periods. The transmit OFF power shall not

exceed the values specified in table below

Channel bandwidth / Minimum output power / measurement bandwidth

1.4

MHz

3.0

MHz

5

MHz

10

MHz

15

MHz

20

MHz

Transmit OFF power -50 dBm

Measurement

bandwidth 1.08 MHz 2.7 MHz 4.5 MHz 9.0 MHz 13.5 MHz 18 MHz


Configured UE transmitted Output Power

Test: set P-Max to -10, 10 and 15 dBm, measure PCMAX

IE P-Max (SIB1) = PEMAX

Channel bandwidth / maximum output power

1.4

MHz

3.0

MHz

5

MHz

10

MHz

15

MHz

20

MHz

PCMAX test point 1 -10 dBm ± 7.7

PCMAX test point 2 10 dBm ± 6.7

PCMAX test point 3 15 dBm ± 5.7

To verify that UE follows rules sent via

system information, SIB


LTE Power versus time

)}())(()())((log10,min{)( TFO_PUSCHPUSCH10MAXPUSCH ifiTFPLjPiMPiP

Bandwidth allocation TPC commands Given by higher layers

or not used

RB allocation

is main source for

power change

Not scheduled

Resource block


2

Accumulative TPC commands

TPC Command Field

In DCI format 0/3

Accumulated

[dB]

0 -1

1 0

2 1

3 3

PUSCH

minimum

power in LTE


Absolute TPC commands

TPC Command Field

In DCI format 0/3

Absolute [dB]

only DCI format 0

0 -4

1 -1

2 1

3 4

PUSCH

Pm

)}())(()())((log10,min{)( TFO_PUSCHPUSCH10MAXPUSCH ifiTFPLjPiMPiP

-4 -1


Relative Power Control

0 .. 9 sub-frame# 1 2 3 4 radio frame


RB change

RB change

Power pattern A

Power pattern C


RB change

Power pattern B

l The purpose of this test is to verify

the ability of the UE transmitter to set

its output power relatively to the

power in a target sub-frame, relatively

to the power of the most recently

transmitted reference sub-frame, if the

transmission gap between these sub-

frames is ≤ 20 ms.


Power Control – Relative Power Tolerance

l Various power ramping patterns are defined

ramping up

ramping down

alternating


UE power measurements – relative power change

Power

FDD test patterns

0 1 9 sub-frame#

Power

TDD test patterns

0 2 3 7 8 9 sub-frame#

Sub-test Uplink RB allocation TPC command Expected power

step size

(Up or

down)

Power step size

range (Up or

down)

PUSCH/

ΔP [dB] ΔP [dB] [dB]

A Fixed = 25 Alternating TPC =

+/-1dB 1 ΔP < 2 1 ± (1.7)

B Alternating 10 and 18 TPC=0dB 2.55 2 ≤ ΔP < 3 2.55 ± (3.7)

C Alternating 10 and 24 TPC=0dB 3.80 3 ≤ ΔP < 4 3.80 ± (42.)

D Alternating 2 and 8 TPC=0dB 6.02 4 ≤ ΔP < 10 6.02 ± (4.7)

E Alternating 1 and 25 TPC=0dB 13.98 10 ≤ ΔP < 15 13.98 ± (5.7)

F Alternating 1 and 50 TPC=0dB 16.99 15 ≤ ΔP 16.99 ± (6.7)

test for

each

bandwidth,

here 10MHz


UE aggregate power tolerance

Aggregate power control tolerance is the ability of a UE to maintain its power in

non-contiguous transmission within 21 ms in response to 0 dB TPC commands

TPC command UL channel Aggregate power tolerance within 21 ms

0 dB PUCCH ±2.5 dB

0 dB PUSCH ±3.5 dB

Note:

1. The UE transmission gap is 4 ms. TPC command is transmitted via PDCCH 4 subframes preceding

each PUCCH/PUSCH transmission.

P

Time = 21 milliseconds

UE power with

TPC = 0

Tolerated UE power

deviation


UE aggregate power tolerance

Power

FDD test patterns

0 5 0 5 0

sub-frame#

Power

TDD test patterns

3 8 3 8 3

sub-frame#

Test performed with scheduling gap of 4 subframes


UE power measurement – timing masks

End of OFF power

20µs 20µs

Transient period Transient period

Start of OFF power

Start of ON power

requirement

Start Sub-frame End sub-frame

End of ON power

requirement

* The OFF power requirements does not

apply for DTX and measurement gaps

Timing definition OFF – ON commands

Timing definition ON – OFF commands


Power dynamics

PUSCH = ON PUSCH = OFF PUSCH = OFF time

Please note: scheduling cadence for power dynamics


Tx power aspects RB power = Ressource Block Power, power of 1 RB TX power = integrated power of all assigned RBs


Resource allocation versus time

PUSCH allocation, different #RB and RB offset

PUCCH

allocation

No resource

scheduled


LTE scheduling impact on power versus time

TTI based scheduling.

Different RB allocation

Impact

on UE

power


Transmit signal quality – carrier leakage

f

Parameters Relative Limit (dBc)

Output power >0 dBm -25

-30 dBm ≤ Output power ≤0 dBm -20

-40 dBm Output power < -30 dBm -10

Carrier leakage (The IQ origin offset) is an additive sinusoid waveform

that has the same frequency as the modulated waveform carrier frequency.

Frequency error

fc Fc+ε


Impact on Tx modulation accuracy evaluation

l 3 modulation accuracy requirements

l EVM for the allocated RBs

l LO leakage for the centred RBs ! LO spread on all RBs

l I/Q imbalance in the image RBs

frequency

RF carrier

RB0 RB1 RB2 RB3 RB4 RB5

level

signal

noise

LO leakage

I/Q imbalance

EVM


Inband emissions

Used

allocation <

½ channel

bandwidth

channel bandwidth

3 types of inband emissions: general, DC and IQ image


Carrier Leakage Carrier leakage (the I/Q origin offset) is a form of interference caused by crosstalk or DC offset.

It expresses itself as an un-modulated sine wave with the carrier frequency.

I/Q origin offset interferes with the center sub carriers of the UE under test.

The purpose of this test is to evaluate the UE transmitter to verify its modulation quality in

terms of carrier leakage.

DC carrier leakage

due to IQ offset

LO

Leakage

Parameters Relative

Limit (dBc)

Output power >0 dBm -25

-30 dBm ≤ Output power ≤0 dBm -20

-40 dBm Output power < -30 dBm -10


Inband emmission – error cases DC carrier leakage

due to IQ offset


Inband emmission – error cases Inband image

due to IQ inbalance


DC leakage and IQ imbalance in real world …


UL Modulation quality: Constellation diagram LTE PUSCH uses

QPSK, 16QAM

and 64 QAM (optional)

modulation schemes.

In UL there is only 1 scheme

allowed per subframe


Error Vector Magnitude, EVM

Error Vector

Q

I

Ideal (Reference) Signal

Measured

Signal

Φ

Phase Error (IQ error phase)

Magnitude Error (IQ error magnitude)

Σ

Demodulator Ideal

Modulator Input Signal

-

+

011001…

Reference Waveform

Measured Waveform

Difference Signal


Error Vector Magnitude, EVM 7 symbols / slot

0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6 time

frequency

PUSCH symbol

Demodulation Reference

symbol, DMRS

Parameter

Unit Level

QPSK % 17.5

16QAM % 12.5

64QAM % [tbd]

Limit values


Error Vector Magnitude, EVM

Cyclic

prefix

OFDM

Symbol

Part equal

to CP

1 SC-FDMA symbol, including Cyclic Prefix, CP CP center

FFT Window size

FFT window size depends

on channel bandwidth and

extended/normal CP length


Cyclic prefix aspects

OFDM symbol is periodic!

Cyclic prefix does not provoque

phase shift

OFDM symbol n OFDM symbol n-1

We can observe a phase shift

Content is

different in each

OFDM symbol

CP CP

part CP

CP

part


Time windowing

Cyclic

prefix

OFDM

Symbol

Part equal

to CP

1 SC-FDMA symbol, including Cyclic Prefix, CP

Cyclic

prefix

OFDM

Symbol

Part equal

to CP

1 SC-FDMA symbol, including Cyclic Prefix, CP

Continuous phase shift

Difference in phase shift

Phase shift between SC-FDMA

symbols will cause side lobes

in spectrum display!


Time windowing

Cyclic

prefix

OFDM

Symbol

Part equal

to CP

Cyclic

prefix

OFDM

Symbol

Part equal

to CP

Continuous phase shift Difference in phase shift

Tx Time window Tx Time window

Tx time window creates

some kind of clipping in

symbol transitions

Tx time window can be used

to shape the Tx spectrum in

a more steep way, but ….


Time windowing

Cyclic

prefix

OFDM

Symbol

Part equal

to CP

Cyclic

prefix

OFDM

Symbol

Part equal

to CP

Continuous phase shift Difference in phase shift

Tx Time window Tx Time window

Tx time window creates

some kind of clipping in

symbol transitions

Tx time window will create

a higher Error Vector Magnitude!

Here the Tx time window of 5µsec causes

Some mismatch between the 2 EVM

Measurements of the first SC-FDMA symbol


EVM vs. subcarrier

f

f0 f2 f1 f3

Nominal subcarriers

Each subcarrier

Modulated with

e.g. QPSK

. . . .

Integration of all

Error Vectors to

Display EVM curve

Error vector

Error vector

Note: simplified figure: in reality you

compare the waveforms due to SC-FDMA


EVM vs. subcarrier


EVM Equalizer Spectrum Flatness

2

2

*12

|)((|

|))((|*12

1

log*10)(fECA

fECAN

fP RBNRB

f

f0 f2 f1 f3

Nominal subcarriers

Subcarriers before

equalization

Amplitude Equalizer

coefficients

Integration of all

amplitude equalizer

coefficients to display

spectral flatness curve

The EVM equalizer spectrum flatness is defined as the variation in dB of the equalizer coefficients

generated by the EVM measurement process.

The EVM equalizer spectrum flatness requirement does not limit the correction applied to the signal

in the EVM measurement process but for the EVM result to be valid,

the equalizer correction that was applied must meet the

EVM equalizer spectral flatness minimum requirements.


Spectrum flatness calculation

A(f)

f

Equalizer tries to

set same power level for

all subcarriers

1-tap equalization =

Interpreting the frequency

Selectivity as scalar factor

1-tap equalization =

Calculating scalar to

amplify or attenuate 2

2

*12

|)((|

|))((|*12

1

log*10)(fECA

fECAN

fP RBNRB


Spectral flatness


Harmonics, parasitic

emissions, intermodulation

and frequency conversion

from

modulation

process

Output RF Spectrum Emissions

Spurious domain

RB

Channel bandwidth Spurious domain

ΔfOOB

ΔfOOB

E-UTRA Band

Worst case:

Resource Blocks allocated at

channel edge

Spectrum Emission Mask – SEM

-> measurement point by point (RBW)

Adjacent Channel Leakage Ratio – ACLR

-> integration (channel bandwidth)

occupied

bandwidth

Out-of-band emissions Spurious Emissions


Adjacent Channel Leakage Ratio, ACLR

2 adjacent WCDMA

carriers, 5MHz BW

1 adjacent LTE

carrier, 20MHz BW

Active LTE

carrier, 20MHz BW


Occupied Bandwidth - OBW

99% of mean power

Occupied bandwidth is defined

as the bandwidth containing 99 %

of the total integrated mean power

of the transmitted spectrum

Transmission

Bandwidth [RB]

Transmission Bandwidth Configuration [RB]

Channel Bandwidth [MHz]

Res

ou

rce

blo

ck

Ch

an

nel e

dg

e

Ch

an

nel e

dg

e

DC carrier (downlink only)Active Resource Blocks


Impact on SEM limit definition

Spectrum emission limit (dBm)/ Channel bandwidth

ΔfOOB

(MHz)

1.4

MH

z

3.0

M

Hz

5

M

Hz

10

M

Hz

15

M

Hz

20

M

Hz

Measurement

bandwidth

0-1 -10 -13 -15 -18 -20 -21 30 kHz

1-2.5 -10 -10 -10 -10 -10 -10 1 MHz

2.5-5 -25 -10 -10 -10 -10 -10 1 MHz

5-6 -25 -13 -13 -13 -13 1 MHz

6-10 -25 -13 -13 -13 1 MHz

10-15 -25 -13 -13 1 MHz

15-20 -25 -13 1 MHz

20-25 -25 1 MHz

Limits depend

on channel

bandwidth

Limits vary

dependent on offset

from assigned BW


LTE Uplink: PUCCH

frequency

Allocation of

PUCCH only.


PUCCH measurements

PUCCH is transmitted on the 2 side

parts of the channel bandwidth


LTE Receiver Measurements

1 Reference sensitivity level

2 Maximum input level

3 Adjacent Channel Selectivity (ACS)

4 Blocking characteristics

4.1 In-band blocking

4.2 Out-of-band blocking

4.3 Narrow band blocking

5 Spurious response

6 Intermodulation characteristics

6.1 Wide band Intermodulation

7 Spurious emissions


RX Measurements – general setup

Receive Sensitivity Tests

User

definable

DL

assignment

Table

(TTI based)

Specifies DL scheduling

parameters like

RB allocation

Modulation, etc.

for every TTI (1ms)

Transmit data

according to

table on PDSCH

ACK/NACK/DTX

Counting

Receive feedback

on PUSCH

or PUCCH

+

AWGN

Blockers

Adjacent channels

requirements in terms of throughput (BLER) instead of BER

Use both

Rx Antennas


RX sensitivity level

Channel bandwidth

E-UTRA

Ban

d

1.4 MHz

(dBm)

3 MHz

(dBm)

5 MHz

(dBm)

10 MHz

(dBm)

15 MHz

(dBm)

20 MHz

(dBm)

Duplex

Mode

1 - - -100 -97 -95.2 -94 FDD

2 -104.2 -100.2 -98 -95 -93.2 -92 FDD

3 -103.2 -99.2 -97 -94 -92.2 -91 FDD

4 -106.2 -102.2 -100 -97 -95.2 -94 FDD

5 -104.2 -100.2 -98 -95 FDD

6 - - -100 -97 FDD

Criterion: throughput shall be > 95% of possible maximum

(depend on RMC)

Sensitivity depends on band,

channel bandwidth and RMC

under test

Extract from TS 36.521


Block Error Ratio and Throughput

Rx

quality DL

signal

Channel

setup Criterion: throughput shall be

> 95% of possible maximum

(depending on RMC)


Rx measurements: BLER definition

PDCCH, scheduling info

PDSCH, as PRBS

ACK/NACK feedback

Count

#NACKs

and

calculate

BLER

Assumption is that eNB

Power = UE Rx power


Details LTE FDD signaling Rx Measurements

l Rx Measurements

l Counting

– ACKnowledgement (ACK)

– NonACKnowledgement

(NACK)

– DTX (no answer from UE)

l Calculating

l BLER (NACK/ALL)

l Throughput [kbps]


Rx measurements: BLER definition

PDCCH, scheduling info

PDSCH, user data

ACK/NACK feedback

•ACK = UE properly

Receives PDCCH + PDSCH

•NACK = UE properly receives

PDCCH but does not understand

PDSCH

•DTX = UE does not understand

PDCCH

ACK relative =

NACK relative =

DTX relativ =

DTXNACKACK

ACK

###

#

DTXNACKACK

NACK

###

#

DTXNACKACK

DTX

###

#

BLER = DTXNACKACK

DTXNACK

###

##


Throughput versus SNR


Throughput measurements

Max throughput

possible in SISO


Rx measurements - throughput

Throughput

Measurement,

Settings for max

throughput

for SISO:

Number of

Resource blocks

Modulation scheme

Transport block size


Throughput + CQI in LTE

Change of

RF

condition-

> lower

data rate

UE sends

different

CQI

values


MIMO in LTE: BLER and throughput


Throughput measurements

MIMO active,

2 streams with

different data rate


Why do we need fading?

l 3GPP specifies various tests under conditions of fading

l WCDMA performance tests

l HSDPA performance tests

l LTE performance tests

l LTE reporting of channel state information tests

See CMW capability lists for details

l Evaluation of MIMO performance gain requires fading

l Correlated transmission paths in MIMO connection

l Simulation of “real life conditions” in the lab

l Comparison of processing gain for different transmission modes


Most popular MIMO scheme to increase data rates: Spatial Multiplexing

TX

Ant 1

TX

Ant 2

Time

RX

Ant 1

h11

h21

n1

r1

MIMO

RX(e.g. ZF,

MMSE,MLD)

de2

de1

Sp

ace

d1

d2

Matix B

LO

n2

r2

h12

h22

RX

Ant 2

2 X 2

MIMO

Doubles max. data rates, however, at the expense of SNR @ receiver.

Thus, according to Shannon‘s law, decrease of performance.

Makes sense for low order modulation schemes only (QPSK, 16QAM),

or in case of very good SNR conditions, e.g. for receivers close to base stations.

No increase of total transmit power, i.e. distribution of transmit power across multiple transmit antennas!


Internal fading in LTE


BLER results with and without fading


The mobile device evolution

2G

GSM

Voice Call

SMS

…

2.5G/2.75G

GPRS/EDGE

Voice Call

SMS

MMS

WAP

E-Mail

Internet Access

IPv4

...

3G/3.5G

UMTS/HSPA

Voice Call

SMS

MMS

WAP

E-Mail

Internet Access

IPv4

IPv6

VoIP (Skype)

Games

A-GPS

...

3.9G/4G

LTE/LTE-A/HSPA-DC

Voice Call

SMS

MMS

WAP

E-Mail

Internet Access

IPv4

IPv6

VoIP (Skype)

Games

Video Call

A-GPS/SUPL2.0

IMS support

SMS over IMS

Voice/Video over IMS

CSFB

...


Why End-to-End testing?

Smartphone

Voice Call

SMS

MMS

WAP

E-Mail

Internet Access

IPv4

IPv6

VoIP (Skype)

Games

Video Call

A-GPS/SUPL2.0

IMS support

SMS over IMS

Voice/Video over IMS

CSFB

...

All features on a phone have an direct impact on the battery life of the phone and it’s

power consumption, but also on the generated traffic by the phone.

Keywords: lHW and SW of a phone need to be designed in an efficient way for a long battery life

lHW and SW need to be designed in a way, that they provide the service reliable

lEfficient application desig for low IP traffic

...

Focus: lValidation of HW and SW in combination

l Simulation of end-user scenarios in an isolated and controlled environment

l Validation of applications with repeatable and comparable results

…

That‘s why End-to-End test!


Here it is!

Embedded PC

based on Linux!

The „Data Application Unit“!


CMW DAU - Main Features

1. Easy Data Testing IP configuration

l Ready to use Standalone IP configuration for the CMW

l Easy Company LAN integration (DHCPv4, static IP addresses)

l Data continuity during Handover between RATs

l Remote control by MLAPI & SCPI

2. DAU IP services (Applications)

l Provides R&S throughput optimized data applications (ftp, http, …)

l New features like IMS (for VoLTE or SMS over IMS)

l Provides storage for media files (own Hard Disk)

3. Closed environment

l guaranties repeatable and comparable test results


DAU User Interface on the CMW

l Data Application Control (DAC)

l Accessible via Setup-> System -> DAU -> Go to Config

l Data Testing IP configuration

l Start/Stop, Configure global servers like FTP, HTTP


DAU User Interface on the CMW

l Data Application Measurements (DAM)

l Accessible over the CMW Measurements

l Provides User Interface for

– Applications: start Iperf, trigger Ping, send/receive eMails …

– Measurements: Throughput, Traffic statistics

Go to

DAC


Feature Set FW2.1.26

Latency

measurements Overall Throughput

Indication

IPERF Throughput

Measurement


Throughput end to end


End to end testing – ping response, RTT


Integrated Servers FW2.1.26


Introduction IMS – IP Multimedia Subsystem Definition

l IMS (IP multimedia subsystem) itself is not a technology,

it is an architecture

l IMS is an all-IP service layer between transport and application

layer based on common Internet protocols

l IMS architecture enables the connection to networks using

multiple mobile and fixed devices and technologies

l IMS defines an architecture for the convergence of audio, video

and data to enable integrated Multimedia Sessions over fixed and

wireless networks

l The long-term solution for supporting voice services in LTE will be

based on the IMS (IP Multimedia Subsystem) framework.


Introduction IMS – IP Multimedia Subsystem Definition

l TBD

Services: SMS over IMS

Voice over IMS

Video over IMS

IMS is a global access-independent and standard-based IP connectivity

and service control architecture that enables various types of

multimedia services to end-users using common Internet-based

protocols.


3 GPP System Architecture Evolution

S-GW P-GW

Evolved nodeB UE

external

Evolved Packet Core

RAN

IMS

PSTN

PDN MME

Signaling interfaces

Data transport interfaces

All interfaces are packet switched

Access PDN

directly or via IMS

IMS to control

access + data

transfer


IMS Architecture


IMS protocol structure

Layer 1/2 Layer 1/2 (other IP CAN)

Layer 3 control IP / IP sec

UDP / TCP / SCTP

SIP/SDP IKE RTP MSRP

Voice

video messaging

Control plane

user plane

Mobile com specific protocols IMS specific protocols


IMS LTE

IMS Registration and Authentication Comparison with LTE

ATTACH REQUEST REGISTER

AUTHENTICATION REQ

AUTHENTICATION RSP

ATTACH ACCEPT

401 UNAUTHORIZED

REGISTER

200 OK

http://images.google.de/imgres?imgurl=http://www.limousinendienst.de/images/t-Dateien/handy.gif&imgrefurl=http://www.limousinendienst.de/kontakt.htm&h=59&w=38&sz=2&hl=de&start=167&sig2=72pH0B9JOBmiWbfVrI7hVQ&um=1&tbnid=mQnE0XJ9ujKUlM:&tbnh=59&tbnw=38&ei=bZ45R5WmCYe2-QKT2JC2DA&prev=/images%3Fq%3Dhandy%26start%3D162%26imgsz%3Dicon%26ndsp%3D18%26svnum%3D10%26um%3D1%26hl%3Dde%26client%3Dfirefox-a%26rls%3Dorg.mozilla:de:official%26sa%3DN


How to connect E-UTRAN to CS services?

l Connection via IMS: 3GPP and OneVoice initiative

l Voice over LTE Generic Access – VoLGA Forum – interim solution

l CS Fallback CSFB for voice calls to 2G or 3G services – preferred interim solution

l Evolved MSC, eMSC – CS Services via EPS – network operator proposal, interim solution

l SRVCC – Single Radio Voice Call Continuity

l SV-LTE – simultaneous voice and LTE

l OTT, Over the top – propietary solution, application based

First a big mess,

Now it seems to be OneVoice


Voice over IMS: IMS protocol profile Codec mode Source codec bit-rate

AMR_12.20 12,20 kbit/s (GSM EFR)

AMR_10.20 10,20 kbit/s

AMR_7.95 7,95 kbit/s

AMR_7.40 7,40 kbit/s (IS-641)

AMR_6.70 6,70 kbit/s (PDC-EFR)




AMR_SID 1,80 kbit/s (see note 1)

Adaptive Multirate

Codecs are used

In VoIP over IMS


QoS class identifiers QCI

QCI Resource

Type

Priority Packet Delay

Budget

Packet Error

Loss

Rate

Example Services

1

GBR

2 100 ms 10-2 Conversational Voice

2 4 150 ms 10-3 Conversational Video (Live Streaming)

3 3 50 ms 10-3 Real Time Gaming

4 5 300 ms 10-6 Non-Conversational Video (Buffered Streaming)

5

Non-GBR

1 100 ms 10-6 IMS Signalling

6 6 300 ms

10-6

Video (Buffered Streaming)

TCP-based (e.g. www, e-mail, chat, ftp, p2p

file sharing, progressive video, etc.)

7 7 100 ms

10-3

Voice, Video (Live Streaming),

Interactive Gaming

8 8

300 ms

10-6

Video (Buffered Streaming)

TCP-based (e.g. www, e-mail, chat, ftp, p2p

file sharing, progressive video, etc.) 9 9


Voice over LTE – protocol profiles

PHYSICAL LAYER

Medium Access Control

MAC

Radio Link Control

RLC

Packet Data Convergence

PDCP

UDP/ TCP

IP

AMR codec

Use robust header compression or IP

Short PDCP header is used

Use RLC in UM mode

Small sequence number is used

SRB1 and 2 are supported for

DCCH + one UM DRB with QCI 1 for voice

for SIP signaling + one AM DRB QCI 5 for

SIP signaling + one AM DRB QCI 8 for

IMS traffic

TTI bundling + DRX to reduce PDCCH

Signaling + Semi-persistend scheduling

Optimize transmission of

Voice by configuring

Lower layers


CMW500 Data Application Unit Integrated IMS Server

IMS infoscreen

Mobile infoscreen

IMS

Configuration


IP Based communication

server

client

- Source

- Destination

Routing decision based on:

- load

- cost of routing

- broken links

Cause in:

- packet delay

- jitter

- losses


CMW500 Data Application Unit Network Impairment

DAU

l Impairments:

l Delay

l Jitter

l Packet Loss

l Packet Corruption

l Packet Duplication

l Packet Re-ordering

TUN

LAN

DA

U

NOTE: Network Impairment are available for DL traffic

Delay Loss

Application FTP PING HTTP IPERF

Emulate characteristics of a real network


l UP to 7 different Impairment per DAM possible

l Impairments are identified by a filter rule

l IPv4 address filter

l IPv6 address/prefix filter

l Additionally a optional TCP/UDP Port filter

l Feedback provided when error occur

CMW500 Data Application Unit Network Impairment


Functional

testing

Performance

testing

Audio

Quality

testing

Voice over LTE (VoLTE) testing R&S solutions - Overview

LTE attach procedure

IMS Terminal Testing

Session Initiation Protocol (SIP)

Conformance Testing

Audio: echo verification in

loopback mode

Verify audio quality using PESQ®

and POLQA® algorithm

Acoustic analysis: 3GPP TS 26.132

R&S®CMW500

LTE Call-box

R&S®UPV

Audio Analyzer

R&S®CMW500 LTE Protocol Tester

Automated test of impacts of noise, fading, IP traffic impairment…

with R&S Contest

LTE attach procedure

IMS registration

Audio: echo verification in

loopback mode

IP Traffic Logging

Impact of noise, IP traffic impairment

R&S®CMW-PQA


LTE CallBox used for VoLTE Audio Quality Testing

R&S®CMW500

LTE Call-box

R&S®UPV

Audio Analyzer

Scope of Audio Quality testing

lAnalysis of the Audio Quality

l„What is the Audio Quality of the VoLTE call a UE

can perform?“

lVerification of the audio quality with established

mechanisms like PESQ® and POLQA® algorithm

lAcoustic analysis of the signal according to 3GPP

TS 26.132 Release 10

Audio

Quality

testing

Performance

testing

Functional

testing


NEW DAU Features Useful in LTE Integrated IMS Server for Voice over IMS

IMS infoscreen

Mobile

infoscreen

IMS

Configuration

Features:

lLoopback mode or

MediaEndpoint

Connection for separate

DL/UL Analysis

lNarrowband

lWideband

lDifferent Codec Rates

lUseCase: l VoLTE or VoHSPA


l CMW500 establishes LTE

and IMS connection to UE

l Uplink verification:

PESQ/POLQA sequence

from UPV is provided to

UE and sent in uplink to

CMW500; received VoIP

data is converted to analog

(USB soundcard) and

analyzed in UPV

l Test focus:

l UPV analyzes the audio

quality PESQ/POLQA

l Verification of separated

uplink

PESQ/POLQA

analysis

IMS

server Media

Server* RF

to m

icro

ph

one

USB

Connection

*Media Server functionality:

l De-packaging speech data from RTP

l De-Coding digital speech data (e.g. AMR WB)

CMW500 Speech Verification Audio Quality analysis - Uplink


CMW500 Speech Verification Acoustic tests according to 3GPP TS 26.132



l DL or UL verification:

3GGP defined tests

performed by UPV using

an artificial head

l Test focus:

l Acoustic tests according to

3GPP TS 26.132

l Verification of uplink and

downlink

3GPP

TS26.132

analysis

IMS

server

LAN Connection

RF

to m

icro

ph

one

USB

Connection

*Media Server functionality:

l De-packaging speech data from RTP

l De-Coding digital speech data (e.g. AMR WB) fr

om

lo

ud

sp

eaker

Media

Server*


Final Test Setup for VoLTE Acoustic measurements Integrated IMS, integrated Audio Board and Codecs



l establish a VoLTE call

by using internal audio

board and codecs

l Test focus:

l Audio Quality Analysis

PESQ/POLQA

l Acoustic tests according to

3GPP TS 26.132 with artificial

head

PESQ/POLQA

analysis

IMS

server Audio

Codecs

RF

to m

icro

ph

one

UL

Fro

m lou

dsp

ea

ker

DL

Integrated

Audioboard


l Support of different RATs

l Server for FTP, HTTP, IMS and DNS

l IP Impairments

l IP Logging

l IMS Services SMS and VoIP

l PING Latency

l IPERF DNS IPERF TP Streaming

Feature overview with 3.0.20

LTE-FDD LTE-TDD GSM 1xEV-DO

VoIP Call

FTP HTTP IMS

SMS

RAT

IP

Application

WLAN WCDMA

IP-Logging

IP-Impairments

VIDEO Call

PING Latency

Data Application Unit


Radio Access Technologies today

GERAN

UTRAN

CDMA2K

1xEVDO

EUTRAN

LTE coverage is not fully up from day one

-> interworking with legacy networks is essential!!!


Voice calls in LTE

l There is one common solution: Voice over IMS l -> also named Voice over LTE VoLTE or OneVoice initiative

But….

What if IMS is not available at first rollout?

-> interim solution called Circuit Switched Fallback CSFB = handover to

2G/3G

-> or Simultaneous Voice on 1XRTT and LTE, SV-LTE = dual receiver

What is if LTE has no full coverage?

-> interworking with existing technologies, Single Radio Voice Call Continuity,

SRVCC


2G or 3G CS fallback

E-UTRAN MME IMS

Voice call

Voice over IMS is the solution,

but IMS is maybe not available in the first network roll-out.

Need for transition solution:

Circuit Switched Fall Back, CSFB move the call to 2G or 3G


CSFB issues and questions

UE E - UTRAN MME LTE Uu S 1 - MME

GERAN

UTRAN

Um

Uu

SGSN

MSC Server

SGs

Gs

A

Iu - cs

Gb

Iu - ps

S 3

•Is it a handover command or a command to redirect to a new RAN ? i.e.

the UE selects the target cell or the EUTRAN commands the target cell

•Is there any information about the target RAN available (SysInfo)?

•Is there a packet data connection PDN active or not?

•Will the PDN be suspended or continued in the target RAN?

•Will the UE re-initiate the PDN or continue?

Handover or

Redirection?

Target cell

assigned or

selected by UE?


CS fallback options to UTRAN and GERAN

Feature

group

index, UE

indicates

CSFB

support


CS fallback to 1xRTT

E-UTRAN

MME

Serving/PDN GW

SGi

1xRTT CS Access

1xRTT MSC

1xCS IWS

S102

S11 S1-MME

S1-U

A1

A1

Tunnelled 1xRTT messages

1xCS CSFB

UE

1xCS CSFB

UE

S102 is the

reference point

between MME and

1xCS interworking

solution

Tunneling of

messages between

1xRTT MSC and UE


CS fallback - arguments

l E-UTRAN and GERAN/UTRAN coverage must overlap

l No E-UTRAN usage for voice

l No changes on EPS network required

l Gs interface MSC-SGSN not widely implemented

l Increased call setup time

l No simultaneous voice + data if 2G network/UE does not support DTM

l SMS can be used without CS fallback, via E-UTRAN


l Call setup delay

l Call drop due to handover

l Blind hand-over is used for CSFB

l Data applications are interupted

l Legacy RAN coverage needed

Why not CSFB?


Dual receiver 1xCSFB

UE

eNB for LTE

CDMA2000 cell

Circuit switched

1xRTT registration

Packet switched

EUTRAN registration

Dual receiver 1xCSFB UEs can handle separate mobility and

registration procedures 2 radio links at the same

time. UE is registered to 2 networks, no coordination required.

When CS connection in 1xRTT,

dual receiver UE leaves EUTRAN!


SV-LTE: Simultaneous CDMA200 + LTE

UE

eNB for LTE

CDMA2000 cell

Circuit switched

1xRTT connection

Packet switched

EUTRAN connection

Simultaneous Voice UEs can handle 2 radio links at the same

time. UE is registered to MME and CDMA2K independently


OTT – over the top

S-GW P-GW

Evolved nodeB UE

Evolved Packet Core

EUTRAN

PDN

Application

Voice call as application, e.g. Skype, Google talk, …


OTT – over the top - arguments

S-GW P-GW

Evolved nodeB UE

Evolved Packet Core

EUTRAN

PDN

Application

•Propietary solution, needs to be implemented in UE and AS

•Already implemented in computer networks – known application

•Support has to be accepted by operator

•No Inter-RAT handover is possible


SMS transfer in LTE

PHYSICAL LAYER

Medium Access Control

MAC

Radio Resource Control

RRC

Contr

ol &

Measure

ments

Radio Link Control

RLC

Packet Data Convergence

PDCP

EMM ESM User plane

Transport channels

Logical channels

Radio Bearer

Encapsulate SMS in NAS

Control message->

SMS over SG

Send SMS over IMS

Using IP protocol

SMS over IMS


Single Radio Voice Call Continuity

Problem: in first network roll-out,

there is no full LTE coverage. How to

keep call active?

=> SRVCC


Single Radio Voice Call Continuity

eNodeB = EUTRAN VoLTE call

time

VoIP in PS mode

Voice call in CS mode

NodeB = UTRAN

NodeB = UTRAN

Handover to UTRAN

Radio Bearer reconfiguration:

PS to CS mode


Handover – what to discuss?

UE

eNodeB

EUTRAN cell

Redirection command?

UTRAN cell(s)?

Will the UE initiate the

change? -> re-selection

Will the network initiate

the change? ->

redirection or handover

Mandatory

for UE

supporting

CSFB

UE reads

SysInfo

Handover command?

GERAN cell(s)?

NW sends

SysInfo of

Target?

CDMA2K cell(s)?


Handover aspects – what to discuss?

l Some keywords that appear – and to be clarified in next

slides:

l Handover?

l Cell reselection?

l Cell change order?

l Redirection?

l Network assisted cell change, NACC?

l Circuit switched fallback, CS fallback?


Mobility between LTE and WCDMA/GSM Radio Access Aspects

Handover

CELL_PCH

URA_PCH

CELL_DCH

UTRA_Idle

E-UTRA

RRC_CONNECTED

E-UTRA

RRC_IDLE

GSM_Idle/GPRS

Packet_Idle

GPRS Packet

transfer mode

GSM_Connected

Handover

Reselection Reselection

Reselection

Connection

establishment/release

Connection


Connection


CCO,

Reselection

CCO with

optional

NACC

CELL_FACH

CCO, Reselection


Redirection to UMTS

UE

eNodeB

EUTRAN cell

RRC connection release message

with RedirectedCarrierInfo to

UTRAN

NodeB(s)

UTRAN cell(s)

UE will search for

suitable cell on

UARFCN and initiate

CS connection

RRC connection release with redirection without SysInfo

Mandatory

for UE

supporting

CSFB

UE reads

SysInfo


Redirection to UMTS

UE

eNodeB

EUTRAN cell



UTRAN

NodeB

UTRAN cell

UE will go to indicated

cell and initiate CS

connection

RRC connection release with redirection with SysInfo

e-RedirectionUTRA

capability is set

by UE

Sys

Info

Rel. 9

feature UE reads

SysInfo


Redirection to GERAN

UE

eNodeB

EUTRAN cell



GSM

BTS(s)

GSM cell(s)

UE will search for

suitable cell on ARFCN

and initiate CS

connection


Mandatory

for UE

supporting

CSFB


Redirection to GERAN

UE

eNodeB

EUTRAN cell



GSM

UE will go to indicated

cell and initiate CS

connection

RRC connection release with redirection with SysInfo

e-RedirectionUTRA

capability is set

by UE

Sys

Info

Rel. 9

feature

BTS(s)

GSM cell(s)


Handover to UMTS: Packet switched handover

UE

eNodeB

EUTRAN cell

MobilityFromEUTRACommand message

with purpose indicator = handover

to UTRAN

EUTRAN contains targetRATmessagecontainer,

= Inter-RAT info about target cell

NodeB(s)

UTRAN cell(s)

UE will select target cell

on UARFCN and

continue PS connection

Packet Switched handover to UTRAN


Inter-RAT Handover to GERAN: cell change order

UE

eNodeB

EUTRAN cell


with purpose indicator = Cell Change Order

to GPRS

BTS(s)

GPRS cell(s)

UE will search for


and re-initiate PS

connection

Packet Switched cell change order to GPRS without NACC

(network assisted cell change)

Mandatory

for UE

supporting

CSFB

PS connection will be suspended


Inter-RAT Handover to GERAN: cell change order

UE

eNodeB

EUTRAN cell


with purpose indicator = Cell Change Order

to GPRS

BTS

GPRS cell

UE will search for


and initiate PS

connection

Packet Switched cell change order to GPRS with NACC

(network assisted cell change)

Mandatory

for UE

supporting

CSFB

Sys

Info

PS connection will be suspended


Inter-RAT Handover to GERAN: handover

UE

eNodeB

EUTRAN cell


with purpose indicator = handover

to GPRS

BTS

GPRS cell

UE will search for


and continue PS

connection

Packet Switched handover to GPRS

Mandatory

for UE

supporting

CSFB

PS connection will be handed over


LTE-RTT Handover

Circuit Switched Fallback, CSFB

Overview



E-UTRAN

MME

Serving/PDN GW

SGi

1xRTT CS Access

1xRTT MSC

1xCS IWS

S102

S11 S1-MME

S1-U

A1

A1

Tunnelled 1xRTT messages

1xCS CSFB

UE

1xCS CSFB

UE

S102 is the

reference point

between MME and

1xCS interworking

solution

Tunneling of

messages between

1xRTT MSC and UE



UE

eNodeB

EUTRAN cell



1xRTT

1xRTT cell(s)

UE will search for

suitable cell on

UARFCN and initiate

CS connection


Mandatory

for UE

supporting

CSFB

to 1xRTT

MME

CSFB Info

CSFB to 1xRTT

Enhancement: UE can pre-register in 1xRTT network



MobilityFromEUTRACommand

UE EUTRAN

HandoverFromEUTRAPreparationRequest

UE EUTRAN

ULHandoverPreparationTransfer

UE EUTRAN

enhanced 1xCSFB (e1xCSFB)

1) Prepare for

handover,

search for

1xRTT

2) Info about

1xRTT ->

tunnelled via

S102

3) Includes

1xRTT channel

assignment

Time flow




MobilityFromEUTRACommand

UE EUTRAN

HandoverFromEUTRAPreparationRequest

UE EUTRAN


UE EUTRAN

enhanced 1xCSFB (e1xCSFB) + concurrent HRPD handover

1) Prepare for

handover,

search for

1xRTT + HRPD

2) Trigger 2

messages with

info about

1xRTT + HRPD

3) Redirection

to 1xRTT and

handover to

HRPD

Time flow



UE EUTRAN


LTE-eHRPD Handover

Overview


EUTRAN – eHRPD non-roaming

i.e. US subscriber, connected

To home network, leaves

LTE coverage area


EUTRAN – eHRPD, roaming case

i.e. European subscriber

visiting US, connected to roaming

network and leaving LTE

coverage area


Mobility between LTE and HRPD Radio Access Aspects

HRPD active to EUTRAN is

always cell reselection

(via RRC idle)

No handover to

EUTRAN


3 Step Procedure

E-UTRAN needs

to decide, that

HO to HRPD

is required

HO preparation

Connection Request

issued by UE to

HRPD, HRPD prepares

for the arrival of the UE

HO execution

Traffic Channel Assignment

command is delivered

to UE, re-tune radio to

HRPD channel, acquire

HRPD channel, session

configuration

UE attached

to E-UTRAN

Ability of pre-

registration is

indicated

on PBCCH

Pre-registration

• Reduces time for cell re-selection or handover

• Reduces risk of radio link failure

Video over LTE Testing the next step in the end user experience


Node B

Internet

SGW PGW

MME PCRF

EPC / IMS

Node B

Impact due to

l Multipath propagation

l Speed

l …

Impact due to

l Packet delay

l Packet jitter

l Packet loss

l …

Introduction Network view


l Main use cases from a test engineer (operator, manufacturer) perspective:

l Exploring the performance of mobile equipment from the end user perspective

l Measuring E2E throughput with realistic radio conditions

l Evaluating mobility performance

Introduction Testing real life conditions in the lab

l Important aspect for end user perspective: Error free video reception

R&S®CMW500

emulates LTE

network

R&S®AMU200

baseband fader

simulates real life

radio conditions

Contest SW

provides

automation

and reporting

capabilities

CMW-PQA


Receiver

Video transmission over LTE The video processing chain and possible sources for video degradation

Encoder

Uncompressed video

SDI

SMPTE249/292/424

Redundant

information (static

image parts) and

irrelevant data

(details) is omitted

Decoder TX RX Video processor

Output on

screen Restoring the video

information; i.e. the

picture sequence

including redundant

data

Scaling and

conversion to output

format

Transmission

link

(IP, cellular,

broadcast, etc.)

• Encoding artifacts

(blocking)

• Video / audio delay

• Buffer rules are

violated

Impairments on the

transmission link

can cause loss of

information despite

active error

correction

The decoder is usually the less

critical component. But in

conjunction with the video

processor, errors during the

conversion process (e.g. de-

interlacing) are possible


Video transmission over LTE Testing real life conditions in the lab

PC

Contest

TC Control

Video

via MHL

or HDMI

RF


Video transmission over LTE R&S®VTE Video Tester

l Source, sink and dongle testing on MHL 1.2 interfaces and in the future also HDMI 1.4c, etc.

l Realtime difference picture analysis for testing video transmissions over LTE

l Combined protocol testing and audio/video analysis

l Future-ready, modular platform accommodating up to three test modules

l Localized touchscreen user interface

l Integrated test automation and report generation

R&S®VTE Video Tester


Summary

l Video and voice are important services gaining momentum for

the fastest developing radio access technology ever - LTE

l Beside LTE functionality, testing voice/video quality is

essential to judge a good receiver implementation

l R&S provides you with profound expertise and

test solutions on both aspects

l Complete LTE test portfolio ranging from early R&D via IOT

and field testing until conformance and production

l Supplier of a complete range of TV broadcasting transmission,

monitoring and measurement equipment


There will be enough topics

for future trainings

Thank you for your attention!

Comments and questions welcome!

LTE: Introduction, evolution and testing

Technology

Transcript of LTE: Introduction, evolution and testing