lte training @ iac 110316

You take LTE forward. Agilent leads the way

3GPP LTE Technologies

JianHua Wu

Application Engineer


LTE context and timeline

What is LTE?- LTE is a 3GPP project name for the evolution of UMTS- It is now linked with the development of a new air interface- Existed together the evolution of UMTS via HSDPA and HSUPA

Other names of LTE:- Evolved UTRA (E-UTRA) / Evolved UTRAN (E-UTRAN)- Evolved UMTS Terrestrial Radio Access- Evolved UMTS Terrestrial Radio Access Network

Related names:- 3.9G,Super 3G,HSOPA(Evolution of HSDPA/HSUPA with OFDM)- These terms are not standard, and may fade out soon.

LTE Core Network name:- It is called SAE (System Architecture Evolution).- It refers to the evolved core network.


3GPP standards evolution (RAN & GERAN)

99

09

Release Commercial introduction

Main feature of Release

Rel-99 2003 Basic 3.84 Mcps W-CDMA (FDD & TDD)

Rel-4 Trials 1.28 Mcps TDD (aka TD-SCDMA) (LCR)

Rel-5 2006 HSDPA

Rel-6 2007 HSUPA (E-DCH)

Rel-7 2008+ HSPA+ (64QAM DL, MIMO, 16QAM UL). Many smaller features plus LTE & SAE Study items

Rel-8 HSPA+ 2009

LTE 2010+

LTE Work item – OFDMA air interface

SAE Work item New IP core network

Edge Evolution, more HSPA+

Rel-9 2011 – 2014 LTE Evolved MBMS, IMT-Advanced (4G)


IS-136TDMA

PDCGSMIS-95Acdma

Wireless evolution 1990 - 2010

2G

Incre

asin

g e

ffic

ien

cy,

ba

nd

wid

th a

nd

da

ta r

ate

s

2.5G

3G

3.5G

3.9G

4G

HSCSD iModeGPRSIS-95Bcdma

LTE-Advanced Rel-9/10

802.16m ?

E-GPRSEDGE

cdma2000W-CDMA

FDDW-CDMA

TDDTD-SCDMA

LCR-TDD

HSUPAFDD & TDD

1xEV-DORelease B

1xEV-DORelease A

1xEV-DORelease 0

HSDPAFDD & TDD

Edge Evolution

HSPA+

802.11g

802.11a

802.11b

802.16dFixed

WiMAXTM

802.11n

802.11h

WiBRO

X

LTERel-8

802.16eMobile

WiMAXTMUMB


LTE in context

5 major new 3.9G wireless technologies• 3GPP LTE

• 3GPP HSPA+

• 3GPP Edge Evolution

• 3GPP2 UMB (similar to 802.20)

• IEEE WiMAX – (802.16e / WiBRO)

3.9G Goals• Spectral efficiency

• Highest single user data rates

• Less robust higher order modulation schemes and multi-antenna technology ranging from basic Tx and Rx diversity through to full MIMO

3.9G Techniques:• HSPA+ and EDGE Evolution are natural extensions to existing technologies

• LTE, UMB and WiMAX are new OFDM systems with no technical precedent other than the early implementation of WiBRO which is now a WiMAX profile.

LTEE-UTRA

EDGE Evolution HSPA+

802.16eMobile

WiMAXTM

UMBcf 802.20


LTE timeline for 3GPP, GCF & LSTI

2005 2006 2007 2008 2009 2010

Rel-7 Study Phase

Rel-8 Work Phase

Test Specs

Core specs drafted

1st Test Specs

drafted

Commercialrelease?

Proof of concept

GCF certification

Interoperability

Field trials


LTE at a glance


UE categories

UE Category

Max downlink data rate

Number of DL transmit data

streams

Modulation of DL

Max uplink data rate

Modulation of UL

RF Bandwidth

1 10 Mbps 1

QPSK

16QAM

64QAM

5 Mbps

QPSK

16QAM

20M

2 50 Mbps 2 25 Mbps

3 100 Mbps 2 50 Mbps



QPSK

16QAM

64QAM


Operating Band

DOCOMO

(Europe Bands)

TeliaSonera

Metro PCS ,

Verizon


TX/RX Spacing


Flexible Channel Bandwidth


EARFCN

Channel Raster : 100k Hz


LTE Network Architecture

•E-UTRAN (Evolved Universal Terrestrial Radio Access Network) –

3GPP TS 36.300

MME = Mobile

Management

entity

SAE = System

Architecture

Evolution


Logical high level architecture for evolved systemEvolved IP packet core with multi-RAT integration

HSS - Home

subscriber server

IMS - IP

multimedia

subsystem

Inter AS anchor -

Inter access

system anchor

MME - Mobility

management

entity

Op. IP Serv. -

Operator IP

service

PCRF - Policy and

charging rule

control function

UPE - User plane

entity3GPP 23.882 Figure 4.2-1

WiMAX could

connect here

S5b

Evolved Packet Core

WLAN

3GPP IP Access

S2

non 3GPP

IP Access

S2

IASA

S5a

SAE Anchor

3GPP Anchor

S4

SGiEvolved RAN

S1

Op.IP

Serv.(IMS, PSS, etc…)

Rx+

GERAN

UTRAN

Gb

Iu

S3

MMEUPE

HSS

PCRF

S7

S6

SGSN GPRS Core


• OFDM already widely used in non-cellular technologies and was considered by ETSI for UMTS in 1998

• CDMA was favoured since OFDM requires large amounts of baseband processing which was not commercially viable ten years ago

OFDM advantages• Wide channels are more resistant to fading and OFDM equalizers are much simpler to

implement than CDMA• Almost completely resistant to multi-path due to very long symbols• Ideally suited to MIMO due to easy matching of transmit signals to the uncorrelated

RF channels

OFDM disadvantages• Sensitive to frequency errors and phase noise due to close subcarrier spacing • Sensitive to Doppler shift which creates interference between subcarriers• Pure OFDM creates high PAR which is why SC-FDMA is used on UL• More complex than CDMA for handling inter-cell interference at cell edge

Why OFDM for the downlink?


CDMA vs. OFDM

CDMA• All transmissions at full system bandwidth

• Symbol period is short – inverse of system bandwidth

• Users separated by orthogonal spreading codes

OFDM• Transmission variable up to system bandwidth

• Symbol period is long – defined by subcarrier

spacing and independent of system bandwidth

• Users separated by FDMA & TDMA on

the subcarriers


LTE Air Interface OFDM: Orthogonal Carriers

• Closely spaced carriers overlap

• Nulls in each carrier’s spectrum land at

the center of all other carriers for Zero

Inter-Carrier Interference

Next

sub-carrier

You take LTE forward. Agilent leads the wayGroup/Prese

ntation Title

Agilent Septem

• Closely spaced carriers overlap

• Nulls in each carrier’s spectrum land

at the center of all other carriers for

Zero Inter-Carrier Interference

LTE Air Interface Orthogonal Frequency Division Multiplexing

Tu=66.7us

△f=1/Tu=15kHz

△f


Orthogonal Frequency Division Multiplexing

3GPP 25.892 Figure 1: Frequency-Time Representation of an OFDM Signal

OFDM is a digital multi-carrier modulation scheme, which uses a large number of closely-spaced orthogonal sub-carriers.

Each sub-carrier is modulated with a conventional modulation scheme (such as QPSK, 16QAM, 64QAM) at a low symbol rate similar to conventional single-carrier modulation schemes in the same bandwidth.


OFDM vs. OFDMA

User 1

User 2

User 3

Subcarriers

Sym

bols

(Tim

e)

Subcarriers

Sym

bols

(Tim

e)

Orthogonal

Frequency

Division

Multiplexing

Orthogonal

Frequency

Division

Multiple

Access

OFDMA = OFDM + TDMA

User 1

User 2

User 3

OFDM

LTE uses OFDMA – a variation of basic OFDM

OFDMA’s dynamic allocation enables better use of the channel for multiple

low-rate users and for the avoidance of narrowband fading & interference.


Why Single Carrier FDMA (SC-FDMA)?

• SC-FDMA is a new hybrid modulation technique combining the low PARsingle carrier methods of current systems with the frequency allocation flexibility and long symbol time of OFDM

• SC-FDMA is sometimes referred to as Discrete Fourier Transform Spread OFDM = DFT-SOFDM

TR 25.814 Figure 9.1.1-1 Transmitter structure for SC-FDMA.

Frequency domain Time domainTime domain

LTE uses SC-FDMA in the uplink

DFTSub - carrier

MappingCP

insertion

Size -NTX Size -N FFT

Coded symbol rate= R

NTX symbols

IFFT


OFDM modulationQPSK example using N=4 subcarriers

Each of N subcarriers

is encoded with one

QPSK symbol

N subcarriers can

transmit N QPSK

symbols in parallel

One symbol period

The amplitude of the combined 4 carrier signal varies widely

depending on the symbol data being transmittedWith many

subcarriers

the waveform

becomes

Gaussian not

sinusoidal

Null created by transmitting

1,1 -1,-1 -1,1 1,-1

1,1-1,1

1,-1-1,-1

I

Q


SC-FDMA modulationQPSK example using N=4 subcarriers

To transmit the sequence:

1, 1 -1,-1 -1, 1 1,-1

using SC-FDMA first

create a time domain

representation of the IQ

baseband sequence

+1

-1

V(Q)

One SC-FDMA

symbol period

+1

-1

V(I)

One SC-FDMA

symbol period

Perform a DFT of length

N and sample rate

N/(symbol period) to

create N FFT bins

spaced by 15 kHz

V,Φ

Frequency

Shift the N

subcarriers to the

desired allocation

within the system

bandwidth

V,Φ

Frequency

Perform IFFT to create

time domain signal of

the frequency shifted

original

1,1-1,1

1,-1-1,-1

Insert cyclic prefix

between SC-FDMA

symbols and

transmit

Important Note:

PAR is same as

the original QPSK

modulation

1,1-1,1

1,-1-1,-1

I

Q


Comparing OFDM and SC-FDMAQPSK example using N=4 subcarriers

1, 1 -1,-1 -1, 1 1, -1 1, 1 -1,-1 -1, 1 1, -1

SC-FDMAData symbols occupy N*15 kHz for

1/N SC-FDMA symbol periods

60 kHz Frequencyfc

V

CP

15 kHzFrequency

fc

V

CP

OFDMAData symbols occupy 15 kHz for

one OFDMA symbol period

These graphs show how this sequence of QPSK symbols is represented in frequency and time


Physical Layer definitions – TS36.211Frame Structure

Ts = 1 / (15000x2048)=32.552nsec

Ts: Time clock unit for definitions

Frame Structure type 1 (FDD)

FDD: Uplink and downlink are transmitted separately

#0 #2 #3 #18#1 ………. #19

One subframe

One slot, Tslot = 15360 x Ts = 0.5 ms

One radio frame, Tf = 307200 x Ts = 10 ms

Subframe 0 Subframe 1 Subframe 9


Physical Layer definitions – TS36.211Frame Structure- type 2 (TDD)

One slot,

Tslot=15360Ts

GP UpPTSDwPTS

One radio frame, Tf = 307200Ts = 10 ms

One half-frame, 153600Ts = 5 ms

30720Ts

One subframe,

30720Ts

GP UpPTSDwPTS

Subframe #2 Subframe #3 Subframe #4Subframe #0 Subframe #5 Subframe #7 Subframe #8 Subframe #9

5 ms switch-point periodicity

Uplink-downlink

configuration

Downlink-to-Uplink

Switch-point periodicity

Subframe number

0 1 2 3 4 5 6 7 8 9

0 5 ms D S U U U D S U U U

1 5 ms D S U U D D S U U D

2 5 ms D S U D D D S U D D

3 10 ms D S U U U D D D D D

4 10 ms D S U U D D D D D D

5 10 ms D S U D D D D D D D

6 5 ms D S U U U D S U U D

Uplink and downlink configurations

TDD: Subframe 0 and 5 for downlink, others are either downlink or uplink


LTE downlink subframe and slot structure


How OFDM Deals With MultiPath?

Problem: If transmitted symbol interval = receiver capture time the

system even a little delay spread causes problem.

Solution: extend the symbol interval time…..


Cyclic Prefix – Each and every symbol has a guard time at the beginning of the symbol

which allows the receiver to collect multipath from the previous symbol

Tb = “useful” symbol time. Contains all

the information of the burst and is

created from the 256 Inverse-FFT

Ts=Tu + Tcp this is a “ready to

transmit” symbolCP

Tu

Tu

Tcp

Ts

The complete symbol is created in the time

domain by duplicating the back portion of the

useful symbol and transmitting this first. By

duplicating this portion of the time record, this

portion of the waveform is effectively transmitted

twice.

The cyclic-prefix length Tcp should cover the maximum length of the time-

dispersion expected to be experienced.


How OFDM Deals With MultiPath?

1,Cyclic-prefix insertion makes an OFDM signal insensitive to time dispersion as

long as the span of the time dispersion.

2,More power loss in demodulation since only a fraction Tu/(Tu + Tcp) of receiver

power is actually utilized by OFDM demodulator.


Frame Structure Type – generic view

Frequency

#0

#1

#2

#3

#4

#5

#19

#18

#17

#16

NBWDL subcarriers

NBWRB subcarriers (=12)

Po

wer

The minimum allocation

of resources is one

Resource Block

= 12 adjacent

subcarriers for one

0.5ms slot


Downlink Resource Block

Channel bandwidth

[MHz]1.4 3 5 10 15 20

Number of

resource blocks6 15 25 50 75 100

3GPP TS 36.101


Channel Bandwidth Vs Transmission Bandwidth


Downlink RS and Signal Structure

• The mobile terminal used Reference Symbols to make the channel estimation of downlink for schedule optimization.

• Downlink reference symbols are inserted within the first and third last OFDM symbols of each slot and with a frequency-domain spacing of six subcarriers.

• Within each resource block, consisting of 12 subcarriers during one slot, there are thus four reference symbols.

• The RS is always transmitted across the entire operation bandwidth, even if the downlink channel is not fully allocated


Downlink Feature (Review)-Physical channel-

Downlink Physical Layer CapabilityReference Signal Cell-specific reference carries Cell-id

UE-specific reference, MBSFN reference

P-Sync Carries physical layer id (0~2)Zadoff-Chu sequence

S-Sync Carries cell-identity group (0~167)

P-BCH Broadcast Channel (1920bits@N_CP by 40ms)SFN control

PDCCH Carries DL Control Information (HARQ process#,MCS, TPC,MIMO precoding info etc.)

PCFICH Carries Control Format Information ((Num of OFDM symbols of PDCCH in a subframe; 1~4)

PHICH Carries HARQ Indicator (ACK/NACK)

PDSCH Carries data with QPSK, 16QAM or 64QAMLocalized/Distributed (VRB) allocation is possible

PMCH Multicast Channel


Uplink Feature-Physical channel-

Uplink Physical Layer CapabilityPUSCH Carries data with QPSK, 16QAM or 64QAM

Localized/Distributed (Hopping) is possible

Demodulation reference signal for PUSCH

qth Zadoff-Chu sequenceGroup (u) /Sequence (v) Hopping, Cyclic shift change by DCI, Broadcast value and PRS

PUCCH Carries ACK/NACK, CQI with BPSK, QPSK or BPSK+QPSK by Format 1,1a,1b,2,2a,2b

Demodulation reference signal for PUCCH

qth Zadoff-Chu sequenceGroup (u) /Sequence (v) HoppingCyclic shift change at every slot and symbol

PRACH uth Zadoff-Chu sequence1.25kHz subcarrier spacingFormat 0 ~ 3 (FDD), Format 4 (TDD)

Sounding reference signal Used for UL timing adjustmentAllocated at first or last symbolCyclic shift change by higher layer

You take LTE forward. Agilent leads the wayAgilent T&M

Forum

Agilent

Agilent Confidential

Downlink FDD Resource Mapping

NsymbDL OFDM symbols (=7 OFDM symbols @ Normal CP)

Cyclic Prefix

160 2048 144 2048 144 2048 144 2048 144 2048 144 2048 144 2048 (x Ts)

1slot = 15360 Ts

P-SCH

1 frame

13 Aug 2007

10 2 3 4 5 6 10 2 3 4 5 6

0 1 2 3 4 5 6

Subframe 0

10 2 3 4 5 61 0 2 3 4 5 6

PCFICH/PHICH/PDCCH

S-SCH

PBCH

Reference Signal – (Pilot)

No TransmissionSubframe 1


LTE uplink subframe and slot structure

CP configuration for uplink

You take LTE forward. Agilent leads the wayGroup/Prese

ntation Title

Agilent Septem

Agilent Confidential

Page 39

Frame Structure Type (UL)Slot / Subframe / Frame- PUSCH

NsymbDL OFDM symbols (=7 OFDM symbols @ Normal CP)

Cyclic Prefix

160 2048 144 2048 144 2048 144 2048 144 2048 144 2048 144 2048 (x Ts)

1slot = 15360

10 2 3 4 5 6

Reference Signal (Demodulation)

1 slot

#0 #1 #8#2 #3 #4 #5 #6 #7 #9 #10

0#11

1#12

2#19

3#13

4#14

5#15

6#16 #17 #18 1 frame

=10 sub-frames

=10 ms

10 2 3 4 5 6

1 sub-frame=2 slots

=1 ms

13 Aug 2007

PUSCH- Physical uplink shared channel


Uplink Frame Structure Type (FDD)PUCCH Mapping (Formats 1, 1a, 1b )

[Syms 2-4 | Every Slot]

[Syms 0,1,5,6 | Every Slot]

1


Unlike DL, UL DM-RS

Is confined only to User

Frame Structure Type (UL) - Physical Mapping

Note 1: When no PUCCH or PUSCH is scheduled in the uplink, the eNB can request transmission of the

Sounding Reference Signal (SRS), which allows the eNB to estimate the uplink channel characteristics

Note 2: PRACH and SRS not shown for clarity

OOK, BPSK

Rotated

QPSK


LTE / SAE Network Identifiers 3GPP TS 23.401 / TR25.813

PLMN ID

(MCC + MNC)

eUTRAN+EPC+Terminals=EPS(Evolved Packet System)

RNTI是UE的標識，不同的RNTI在不同範圍內標識UE，例如C-RNTI在Cell內，S-RNTI在RNC內，U-

RNTI在PLMN內

. RA-RNTI (Random Access Radio Network Temporary Identifier)- is used during the some transient states.

The S-TMSI (SAE Temporary Mobile Subscriber Identity) is replacing TMSI & P-TMSI in 2G & 3G networks

The TAI is replacing the URA ID, LAI and RAI


Basic channel access modes

Transmit

Antennas

Receive

Antennas

SISO

The Radio

Channel

MISO

Single Input Single Output

Multiple Input Single Output

(Transmit diversity)

Receive

Antennas

Transmit

Antennas

MIMO

The Radio

Channel

SIMO

Single Input Multiple Output

(Receive diversity)

Multiple Input Multiple Output

(Multiple data streams)


MIMO principles

•Transmitting multiple data streams in the same space and time used to be called interference!

•So how does MIMO work?1. MIMO capacity gains come from taking advantage of spatial

diversity in the radio channel

2. Depending on channel conditions and noise levels, the rank (number of simultaneous streams) can be varied

3. The performance can be optimized using precoding

•These three MIMO principles can seem complex to understand particularly abstract mathematical descriptions

•But we intuitively already know these MIMO principles in the way they apply to our perception of audio


Understanding MIMO spatial diversity through Audio -Single Stream (Mono)

Page 45

Note, the combination of SIMO and MISO further improves

robustness but does not provide any MIMO capacity gain

since there is only one stream of data

SISO

M

MISOSIMO

M

SIMO + MISO

≠ MIMO

Taking LTE MIMO from

Standards to Starbucks

Moray Rumney 10th June 2009


Understanding MIMO spatial diversity through Audio -Dual Stream (Stereo)

Page 46

Interference!

• For MIMO to work:• Must have at least as many receivers as transmitted streams

• Must have spatial separation at both transmit and receive antennas

• More transmitters enables beamforming in addition to MIMO

Interference! MIMO!

Interference!





Understanding MIMO precoding through Audio

• MIMO Precoding is a pre-emphasis technique used to improve the separation of the streams at the receiver due to unhelpful coupling in the channel

• In audio systems precoding is similar to stereo “balance”

• If the receiver is not positioned directly between the speakers the received streams will be at different levels

• Adjusting the balance at the transmitter can mitigate the problem

• Balancing requires feedback from the receiver to the transmitter

Page 47

Not enough Right





Understanding MIMO precoding through Audio

• The receiver could just amplify the right channel but in the presence of noise the corrected signal would degrade:

• Precoding the transmission as L, 5R optimizes signal recovery

Page 48

L + NL, 0.2 R + NR

L + NL, R + 5*NR

L + NL, R + NR

Problem!

Solution!





Understanding MIMO Rank adaptation through Audio

•In good radio conditions an FM stereo receiver will attempt to decode both the left and right signals (streams)

•When the noise gets too high the receiver switches to mono and the quality improves although stereo is lost

•This is the audio equivalent of rank adaptation where the number of streams is reduced under poor conditions

•Transmit matrix encoded FM stereo as L + R, L – R

•Receive (L + R) + N1, (L – R) + N2

•Since N1 and N2 are largely correlated, adding the two streams (maximum ratio combining) cancels most of the noise

Page 49





The role of channel correlation and noise in system performance

• In a ideal 2x2 system the potential capacity gain is 2x

• The actual gain depends on how easily the receiver can descramble the simultaneous transmissions – this depends on the amount of unwanted correlation and noise

• In audio systems channel correlation and noise also affects perceived stereo performance

– Spaced living room speakers - lots of correlation degrades stereo, susceptible to external noise

– Open headphones – zero correlation, good stereo but still susceptible to noise

– Closed headphones – zero correlation, minimal noise

Page 50





So what makes a good channel for MIMO?

• A perfect MIMO channel islike the closed headphones: channels 2 and 3 don’t exist

• By simple observation it follows that R0 = T0 and R1 = T1

• This is one case that creates double the capacity

• But suppose we create a simple static channel like this:

• How do we know if it will provide capacity gain?

• This requires deeper analysis

Page 51

1 0

0 1

Channel H

0.8 0.2

0.3 -0.9

Channel H

ch1

ch4

T0

T1

R0

R1





The MIMO challenge: Recovering the signal

• If all four channels are the same the original signal cannotbe recovered since R0 = R1

• R0 = T0 + T1 and R1 = T0 + T1

• But put in a phase inversion e.g. on ch3 we get:

• R0 = T0 - T1 and R1 = T1 + T0

• thus T0 = (R0 + R1)/2 and T1 = -(R0 - R1)/2

• The original signal is completely recovered even though the apparently unwanted ch2 and ch3 exist

Page 52

1 1

1 1

Channel H

1 1

-1 1

Channel H

ch1

ch4

T0

T1

R0

R1






• So is the earlier example good or bad for MIMO?

• We can recover the original signal

• In fact any H matrix other than the unity matrix can be resolved PROVIDED there is no external or internal noise!

• So what kinds of channels are robust to noise?

•

Page 53

0.8 0.2

0.3 -0.9

Channel H

R0 = 0.8 T0 + 0.3 T1

R1 = 0.2 T0 - 0.9 T1

T0 = 1.15 R0 + 0.39 R1

T1 = 0.26 R0 - 1.03 R1

Giving:






• The receiver can untangle the two signals because it knows the coupling coefficients, based on the reference signals

• The RS transmits a known amplitude and phase at different subcarriers and times for each MIMO antenna from which the receiver can calculate the complex channel matrix H

Page 54






• But RS estimation is susceptible to noise

• If the H estimate is wrong the recovered signal is impaired

• Consider these equations for T0 from different channels:

• Errors in T0 recovery happen due to estimation errors in the coefficients or large coefficients amplifying noise N0 and N1

• It is possible to analyze the channel matrix H to determine the sensitivity to noise for signal recovery

Page 55

T0 = 1.15 (R0 + N0) + 0.39 (R1 + N1)

T0 = 27.3 (R0 + N0) + 16.5 (R1 + N1)





Condition Number: Measures the short term MIMO channel performance

R0 = 0.8 T0 + 0.3 T1

R1 = -0.9 T1 + 0.2 T0

0.8 0.2

0.3 -0.9

Channel H

0.8 0.3

0.2 -0.9

Channel HT

0.73 -0.11

-0.11 0.85

Channel HTH Eigenvalues

0.914

0.666

Singular values

0.957

0.815

К = Condition number

0.957 / 0.815 = 1.17

The condition number is the ratio of the singular values of HHT

The dB value of К approximates the increase in SNR required

to recover the signal

Page 56Page 56Page 56





MIMO needs better SNR than SISO

High К increases SNR requirements further

•The extra SNR required to achieve the same recovered signal quality as SISO rises as the condition number rises

Page 57Page 57Page 57





Ped. A Channel Condition Number vs. Freq.

Page 58

Condition number and channel response across 10 MHz, 10 ms

0 dB





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

Diagram of the various UE states

Idle Mode

Cell selection

System

Information

Call/data

setup

Paging

RACH

Connected

Call/data

control

Data flowFrom 3GPP 36.331


LTE – eHRPD HandoversCell reselection and Handover Types

IDLE

2G

CONNECTED

Connection

Establish/

release

Handover

Cell Re-selection

Optimized Handover

(eNodeB decision)

eNB

eHRPD LTE

Cell Re-selection

(UE decision)

eHRPD LTE

1

1

3

3Non-optimized Handover

(eNodeB decision)2

2 Connection

Establish/

release


LTE Cell Re-Selection

UE Serving eNB

Broadcast neighbour cell info

Attach with Serving eNB

Initiate cell reselection

RRC release with no re-direction

Establish eHRPD session with target AN

eHRPD AN


LRE – eHRPD Handover Architecture

• S2a provides a data plane tunnel for forwarding IP data traffic

• S101 provides a control plane tunnel for establishing an eHRPD session


LTE – CDMA non-Optimized Handover

UE Serving eNB eHRPD AN



Configure measurement reports

Send measurement reports

Initiate handover

RRC release with re-direction to target eNB

S2a data plane tunnel

Establish data plane tunnel

Establish eHRPD session with target AN


Forward IP Data traffic


LTE – CDMA Optimized Handover

UE Serving eNBBroadcast neighbour cell info




Initiate handover

Agree handover parameters with target cell

E-UTRA Handover (rrc_conn_reconfig)

S101 control plane tunnel


eHRPD AN

Forward IP data traffic

Created eHRPD session with AN



Establish data plane tunnel


Agilent E6621A PXT, 8960 & IFT software

Agilent is working in collaboration with Verizon to implement the LTE – CDMA (eHRPD) Compliance (Performance) Test Plan•The plan is being implemented with Agilent IFT and operates with the E6621A PXT and 8960•The automated test package will enable Verizon to qualify LTE UE for use on their network•Agilent will make the test scripts available to UE makers to pre-qualify UE before submission to Verizon•During the development phase, Agilent is collaborating with UE vendors with leading InterRAT UE capability.

LTE-CDMA_InterRAT_Performance_Test_Plan.doc

Verizon InterRAT Compliance Test Plan


3.1 CELL SELECTION DUE TO LTE SYSTEM LOST – WITH PREVIOUS SESSION ON TARGET EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE

3.2 CELL SELECTION DUE TO LTE SYSTEM LOST – WITH PREVIOUS SESSION ON SOURCE EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE – A13 AVAILABLE

3.3 CELL SELECTION DUE TO LTE SYSTEM LOST – WITH PREVIOUS SESSION ON SOURCE EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE – A13 NOT AVAILABLE

3.4 CELL SELECTION DUE TO LTE SYSTEM LOST – WITH PREVIOUS SESSION ON TARGET EHRPD AND NO SAVED PARTIAL HSGW CONTEXT

3.5 CELL SELECTION DUE TO LTE SYSTEM LOST – WITH PREVIOUS SESSION ON SOURCE EHRPD WITH NO SAVED PARTIAL HSGW CONTEXT – A13 AVAILABLE

3.6 CELL SELECTION DUE TO LTE SYSTEM LOST – WITH PREVIOUS SESSION ON SOURCE EHRPD WITH NO SAVED PARTIAL HSGW CONTEXT – A13 NOT AVAILABLE

3.7 CELL SELECTION DUE TO LTE SYSTEM LOST – WITH NO PREVIOUS SESSION ON EHRPD

3.8 CELL RESELECTION – WITH PREVIOUS SESSION ON TARGET EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE

3.9 CELL SELECTION – WITH PREVIOUS SESSION ON SOURCE EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE – A13 AVAILABLE

3.10 CELL RESELECTION – WITH PREVIOUS SESSION ON SOURCE EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE – A13 NOT AVAILABLE

3.11 CELL RESELECTION – WITH PREVIOUS SESSION ON TARGET EHRPD AND NO SAVED PARTIAL HSGW CONTEXT

3.12 CELL RESELECTION – WITH PREVIOUS SESSION ON SOURCE EHRPD WITH NO SAVED PARTIAL HSGW CONTEXT – A13 AVAILABLE

3.13 CELL RESELECTION – WITH PREVIOUS SESSION ON SOURCE EHRPD WITH NO SAVED PARTIAL HSGW CONTEXT – A13 NOT AVAILABLE

3.14 CELL RESELECTION – WITH NO PREVIOUS SESSION ON EHRPD

4.1 CELL SELECTION TO 1XRTT DUE TO LTE SYSTEM LOST

4.2 CELL SELECTION TO 1XRTT/HRPD DUE TO LTE SYSTEM LOST

5.1 RRC RELEASE WITH REDIRECTION AND MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON TARGET EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE

5.2 RRC RELEASE WITH REDIRECTION AND MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON SOURCE EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE – A13 AVAILABLE

5.3 RRC RELEASE WITH REDIRECTION AND MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON SOURCE EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE – A13 NOT AVAILABLE

5.4 RRC RELEASE WITH REDIRECTION AND MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON TARGET EHRPD AND NO SAVED PARTIAL HSGW CONTEXT

5.5 RRC RELEASE WITH REDIRECTION AND MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON SOURCE EHRPD WITH NO SAVED PARTIAL HSGW CONTEXT – A13 AVAILABLE

5.6 RRC RELEASE WITH REDIRECTION AND MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON SOURCE EHRPD WITH NO SAVED PARTIAL HSGW CONTEXT – A13 NOT AVAILABLE

5.7 RRC RELEASE WITH REDIRECTION AND MEASUREMENT GAPS SCHEDULED – – WITH NO PREVIOUS SESSION ON EHRPD

5.8 RRC RELEASE WITH REDIRECTION NO MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON TARGET EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE

5.9 RRC RELEASE WITH REDIRECTION NO MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON SOURCE EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE – A13 AVAILABLE

5.10 RRC RELEASE WITH REDIRECTION NO MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON SOURCE EHRPD AND PARTIAL HSGW CONTEXT AVAILABLE – A13 NOT AVAILABLE

5.11 RRC RELEASE WITH REDIRECTION NO MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON TARGET EHRPD AND NO SAVED PARTIAL HSGW CONTEXT

5.12 RRC RELEASE WITH REDIRECTION NO MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON SOURCE EHRPD WITH NO SAVED PARTIAL HSGW CONTEXT – A13 AVAILABLE

5.13 RRC RELEASE WITH REDIRECTION NO MEASUREMENT GAPS SCHEDULED – WITH PREVIOUS SESSION ON SOURCE EHRPD WITH NO SAVED PARTIAL HSGW CONTEXT – A13 NOT AVAILABLE

5.14 RRC RELEASE WITH REDIRECTION NO MEASUREMENT GAPS SCHEDULED – – WITH NO PREVIOUS SESSION ON EHRPD

6 LTE ACTIVE TO 1XRTT/HRPD IDLE

6.1 CELL SELECTION TO 1XRTT DUE TO LTE SYSTEM LOST

6.2 CELL SELECTION TO 1XRTT/HRPD DUE TO LTE SYSTEM LOST

7 EHRPD DORMANT TO LTE IDLE

7.1 MORE PREFERRED SYSTEM RESELECTION

7.2 CELL RESELECTION

8 HRPD/1XRTT DORMANT TO LTE IDLE

8.1 MORE PREFERRED SYSTEM RESELECTION

9 LTE DATA THROUGHPUT PERFORMANCE WITH INTERRAT OPERATIONS - FUTURE

10 LTE SUPPLEMENTARY SIGNALING CONFORMANCE FOR LTE-CDMA INTERRAT CAPABLE DEVICES

10.1 RRC UE FEATURE GROUP SUPPORT

Verizon InterRAT Compliance Test Plan


LTE - eHRPD handover demo

SERVER(s)

• SMS

• MMS

• SIP v6

• HTTP

• FTPRF

Proprietary

i/f

UE under test

8960 eHRPD cell

LAN

CLIENT

• DUT control

• IFT - test case script(s)

USB

Single DRB

SISO 10MHz channelPXT LTE cell



SERVER(s)

• SMS

• MMS

• SIP v6

• HTTP

• FTPRF

Proprietary

i/f

UE under test

PXT LTE cell

8960 eHRPD cell

LAN

CLIENT

• DUT control


USB

Step 1: setup of an LTE end to end IP connection



SERVER(s)

• SMS

• MMS

• SIP v6

• HTTP

• FTPRF

Proprietary

i/f

UE under test

8960 eHRPD cell

LAN

CLIENT

• DUT control


USB

Step 2: verification of LTE end to end IP connection

PXT LTE cell



SERVER(s)

• SMS

• MMS

• SIP v6

• HTTP

• FTPRF

Proprietary

i/f

UE under test

8960 eHRPD cell

LAN

CLIENT

• DUT control


USB

Step 3: handover to eHRPD serving cell

PXT LTE cell



SERVER(s)

• SMS

• MMS

• SIP v6

• HTTP

• FTPRF

Proprietary

i/f

UE under test

8960 eHRPD cell

LAN

CLIENT

• DUT control


USB

Step 4: verification of e2e IP in eHRPD serving cell

PXT LTE cell


Verizon Wireless LTE-eHRPD Inter-RATCompliance Testing with IFT


What is LTE voice ?

Through LTE network?

Through legacy 2G/3G?


Support for Voice

• 3GPPs long term solution for voice is to use VoIP and an IMS based core network

• It will take time for all networks to support this

• For networks which do not support IMS several technologies are being considered, namely:-

– CSFB (Circuit Switched Fall Back)

– SVLTE (Simultaneous Voice and Data LTE)

– VoLGA (Voice over LTE Generic Access)

• VoLGA involves sending the CS data over an LTE PS bearer- this is not discussed further in this paper

• SRVCC will be natural in 3GPP through IMS ,also named as “Voice over LTE “,” VoLTE” strongly supported by GSMA

SRVCC : Single Radio Voice Call Continuity


Circuit switched Fallback to 1xRTT

1xCSFB UE

1xRTT CS Access

1xRTT

MSC

1xCS WS

MME

1xCSFB UE

E-UTRANServing/PD

N GW

A1

A1

S102

S1-U

S11

S102 SGi

S1-MME

cdma Network

LTE Network

Tunneled 1xRTT messages*CS Fallback to 1xRTT and IMS-Based services shall be able to co-exist in the same operator’s network


SVLTE

CDMA BTS

BSC/ MSC

E-UTRAN MME

CS Core Network

IP

LTE

Data

CDMA

Voice

• Supports simultaneous voice and data

• UE has 2 complete radios

• Voice provided through CDMA

• Data provided via LTE link

• No interworking required

• SVLTE may be the preferred choice for CS voice on CDMA/LTE networks


CSFB (Requires S102 control plane tunnel)

• Requires 2 baseband ICs (LTE + CDMA)

• Some opportunity to share RF resources

• Significant additional protocol complexity

• Control plane tunnel required for establishing pre-registration with the CDMA cell (via LTE signaling)

• More complex than 2G/3G CSFB due to the lack of interworking at the core network level

• CSFB may be the preferred choice for CS voice on 2G/3G/LTE networks

UEServing eNB





Tunnel paging info from CDMA BTS to LTE enBRRC release with re-direction to CDMA BTS

S102control plane tunnel

CDMA BTS

register UE with 1x cdma2000 base

station


Establish voice call between UE and CDMA cell

Page UE


Circuit switched Fallback to GERAN/UTRAN

LTE/UMTS UE

UTRAN

GERAN

E-UTRAN

SGSN

MME

MSC server

LTE/UMTS UE

S1-MMELTE-Uu

Uu

Um

Lu-PS

Gb Gs

Lu-CS

SGs

S

3

A

UMTS Network

LTE Network

*CS Fallback and IMS-Based services shall be able to co-exist in the same operator’s network


Single radio voice Call Continuity (SRVCC)

• The continuity of voice when a customer moves from LTE to where LTE coverage is not available

• In 2009 ,the consortium includes AT&T,Orange, Verizon,Vodafone,Alcatel-Lucent,Ericsson ,and other key players announced “One Voice” initiative

• GSMA VoLTE initiative was formally announced at MWC in 2010

• It is voice over IMS network

• SR-VCC is in 3GPP TS 23.216 in R9


Single radio voice Call Continuity (SRVCC)

LTE/UMTS UE

GERAN/UTRAN

E-UTRAN

SGSN

MME

MSC server

LTE/UMTS UE

S1-MME

LTE-Uu

Uu/Um

Gb/Lu-PS

Lu-CS/A

SGi

S3

IMS

Serving/

PDN GW

HSS

S1-U

S6a

Sv

S11

Bearer path before HO

Bearer path after HO

SIP Signaling path before HO


Thanks!

lte training @ iac 110316

Documents