51090184 agilent lte

Concepts of 3GPP LTE Sonali Sarpotdar

16 Jan 2008

Concepts of 3GPP LTE

Agenda

• LTE Context and Timeline

• LTE major features

• Overview of the LTE air interface

• Agilent LTE design and test solutions

• Simulation

• Baseband

• Sources

• Analysis

• Integrated mobile test platform


Agenda






3GPP standards evolution (RAN & GERAN)

1999

2010

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)

Rel-5 2006 HSDPA

Rel-6 2007 HSUPA

Rel-7 2008+ HSPA+ (64QAM DL, MIMO 16QAM

UL). Many smaller features plus

LTE & SAE Study items

Rel-8 2009-10? LTE Work item – OFDMA air interface

SAE Work item New IP core network

Edge Evolution, more HSPA+


LTE context and timeline

The many faces of LTE

• LTE is the 3GPP project name for the evolution of UMTS

• LTE is now linked with the development of a new air interface but the evolution of UMTS via HSDPA and HSUPA is still happening

• The official terminology for the new LTE radio system is:

• Evolved UTRA / Evolved UTRAN

• Evolved UMTS Terrestrial Radio Access

• Evolved UMTS Terrestrial Radio Access Network

• Earlier names for this included:• 3.9G

• HSOPA - Evolution of HSDPA/HSUPA with OFDM

• Super 3G

• This naming is not standard and may fade out but 3.9G is likely to stick

• For this paper LTE is assumed to be E-UTRA & E-UTRAN

• SAE – System Architecture Evolution refers to the evolved core network


3.9GUMB

cf 802.20LTE

E-UTRAEDGE

EvolutionHSPA+

802.16eMobile

WiMAXTM

3.5G

3G

HSUPAFDD & TDD

IS-95Bcdma

HSCSD iMode2.5G

2GIS-136TDMA

PDCGSM

GPRS

E-GPRSEDGE

802.11g

IS-95Acdma

IS-95Bcdma

IS-95Ccdma2000

802.11a

802.11b

1xEV-DORelease B

1xEV-DORelease A

WiBRO

1xEV-DORelease 0

W-CDMAFDD

HSDPAFDD & TDD

W-CDMATDD

TD-SCDMALCR-TDD

802.16dFixed

WiMAXTM

802.11n

802.11h

Wireless evolution – five competing 3.9G systems


LTE in context

• LTE is just one of five major new wireless technology developments

• 3GPP LTE

• 3GPP HSPA+

• 3GPP Edge Evolution

• 3GPP2 UMB (similar to 802.20)

• IEEE WiMAX – (802.16e / WiBRO)

• All five systems share very similar goals in terms of spectral efficiency, with the wider systems providing the highest single user data rates

• Spectral efficiency is primarily achieved through use of less robust higher order modulation schemes and multi-antenna technology ranging from basic Tx and Rx diversity through to full MIMO

• 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.


LTE standards development timing

2005 2006 2007 2008 2009 2010

Rel-7 Study Phase

Rel-8 Work Phase

Test Specs

First UE

certification?

Core specs

drafted

• 3GPP plan @ Aug 2007; Final specs - Feb 08, Initial Conformance tests - Sept 08

• Timeline has slipped about 6 months but still considered a stretch goal by many

• Historically, test specs have been much more than 3 months after core specs but the

gap between core specs and conformance is consistently dropping

• UE certification not possible until after test implementation and validation

• Commercial release is hard to predict but is very unlikely before 2010

First Test

Specs

drafted

Commercial

release?


Agenda






LTE major features

Feature Capability

Access modes FDD & TDD – each with their own frame structure

Variable channel BW 1.4, 3 , 5, 10, 15, 20 MHz

All bandwidths supported by FDD and TDD

Baseline UE capability 20 MHz UL/DL, 2 Rx, one Tx antenna

User Data rates DL 172.8 Mbps / UL 86.4 Mbps @ 20 MHz BW

(2x2 DL SU-MIMO & non-MIMO 64QAM on UL)

Downlink transmission OFDM using QPSK, 16QAM, 64QAM

Uplink transmission SC-FDMA using QPSK,16QAM, 64QAM

DL Spatial diversity Open loop TX diversity

Single-User MIMO up to 4x4 supportable

UL Spatial diversity Optional open loop TX diversity, 2x2 MU-MIMO,

Optional 2x2 SU-MIMO


LTE major features

Feature Capability

Transmission Time Interval 1 ms

H-ARQ Retransmission

Time

7 or 8ms* (This is tight and one of the hardest

specs to meet in baseband)

*under negotiation

Frequency reuse Static & semi-static (reuse per UE)

Frequency hopping Intra-TTI: Uplink once per .5ms slot

Downlink once per 66μs symbol

Inter-TTI Across retransmissions

Bearer services Packet only – no circuit switched voice or data

services are supported � voice must use VoIP

Unicast Scheduling

schemes

Frequency selective (partial band)

Frequency diversity by frequency hopping

Multicasting Enhanced MBMS with SFN and cell-specific content


Why did 3GPP want LTE?

• Much untapped potential in HSDPA + HSUPA (HSPA+)

• But some LTE requirements can’t be met by HSPA+

• LTE goal is to provide further benefits

• Spectrum Flexibility

• Higher Peak Data Rates with wider 20 MHz channel bandwidth

• OFDM Access better suited for Broadcast Services

• OFDM enables less complex implementation of Advanced

Antennas/MIMO Technology

• Reduced terminal complexity

• LTE itself has some less complex aspects

• But terminals will have to carry the legacy of GSM, GPRS,

W-CDMA and HSPA which increases overall complexity


LTE vs. HSPA+

Attribute HSPA+ (Rel-8) LTE targets

Peak Data Rate / 5 MHz sector

in ideal radio conditions

DL – 42 Mbps

UL – 10 Mbps

DL – 43.2 Mbps

UL – 21.6 Mbps

Peak Data Rate / 20 MHz sector

in ideal radio conditions

Not possible without

multi-carrier

DL – 172.8 Mbps

UL – 86.4 Mbps

Cell Edge improvement

compared to HSPA Release 6

Evolved HSPA & LTE - DL – 3x to 4x; UL – 2x to 3x

All solutions will benefit from ongoing improvements to the

radio interface such as UE RX diversity, equalization,

interference cancellation; MIMO, higher order modulation etc.

Spectral Efficiency (real world)

Latency: End to End Ping Delay 40 ms

Latency: Idle to Active Currently around 600ms

Goal to reduce to 100 ms

<100 ms

Flexible Bandwidth Utilization? 5 MHz unless multi-

carrier is developed

1.4 MHz to 20 MHz

Suitability for MIMO extensions Challenging with CDMA Much easier with OFDM


IMS

TE MT UTRAN

SMS-SCEIRTE MT

BillingSystem*

R Um

GERAN

WAG

Uu

HLR/AuC*

HSS*

R

C

Wn Wp

Wu

WLAN

UEWw

Intranet/

Internet

Wa

Wm

Wf

Iu

Gn

Gb, Iu

GfGr

Gd

Ga

GiGn/Gp

Gc

SMS-GMSC

SMS-IWMSC

WiOCS*

SGSN

SGSN

Note: * Elements duplicated for picture

layout purposes only, they belong to the

same logical entity in the architecture

baseline.

** is a reference point currently missingTraffic and signaling

Signaling

HLR/

AuC*

3GPP AAA

Proxy

GaGy

CDF

CGF*

3GPP AAA

Server

PCRF AF

Rx+ (Rx/Gq)

Gx+ (Go/Gx)

OCS*

UE

P-CSCF

Mw

Cx Dx

Wa

Wg

Gm

SLFHSS*

CSCF

MRFP

IMS-

MGW

Wo

D/Gr

Dw

Mb

PDG

CGF*

WLAN Access

Network

Wx

MbGGSN

Wz

Wd

BM-SCGmb

Gi

MSC

Gs

PDN

**

BillingSystem*

Wf

Wy

Logical baseline architecture for 3GPP

23.882

Figure 4.1-1

The point

here is the

complexity,

gaps and

overheads

in existing

CS/PS

networks


Simplified LTE network elements and interfaces

S1

S1

S1

S1

X2

X2

3GPP TS 36.300 Figure 4: Overall Architecture

MME = Mobile

Management

entity

SAE =

System

Architecture

Evolution


Logical high level architecture for evolved system

Evolved IP packet core with multi-RAT integration

23.882

Figure 4.2-1

S5b

Evolved Packet Core

WLAN 3GPP IP Access

S2

non 3GPP IP Access

S2

IASA

S5a

SAE Anchor

3GPP Anchor

S4

SGi Evolved RAN

S1

Op. IP

Serv. (IMS, PSS, etc…)

Rx+

GERAN

UTRAN

Gb

Iu

S3

MME UPE

HSS

PCRF

S7

S6

* Color coding: red indicates new functional element / interface

SGSN GPRS Core

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

entity

WiMAX could

connect here


LTE documents from the study phase (Rel-7)

The latest study phase technical documents can be found at:

• www.3gpp.org/ftp/Specs/html-info/25-series.htm

• 23.882 System Architecture Evolution

• 25.912 Feasibility study for Evolved UTRA and UTRAN

• 25.913 Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN

(E-UTRAN)

• 25.813 Radio interface protocol aspects

• 25.814 Physical Layer Aspects for Evolved UTRA

Most of these are no longer being kept up to date now the

work has transferred to the 36-series (Rel-8) specifications

However these document still provide a useful overview that

may be difficult to find in the formal specifications


LTE 3GPP Specifications (Rel-8)

• After the LTE study phase in Rel-7, the LTE specifications

are defined in the 36-series documents of Rel-8

• There are six major groups of documents

• 36.8XX & 36.9XX Technical reports (background information)

• 36.1XX Radio specifications (and eNB conformance testing)

• 36.2XX Layer 1 baseband

• 36.3XX Layer 2/3 air interface signalling

• 36.4XX Network signalling

• 36.5XX UE Conformance Testing

• The latest versions of these documents can be found at

www.3gpp.org/ftp/Specs/html-info/36-series.htm


Agenda






LTE – Impεεεεnetrαβαβαβαβle?

( ) ( ) ( )

∑

−

−=

−∆+⋅= −

12/

2/

212

,

RBsc

ULRB

RBsc

ULRB

s,CP)(

NN

NNk

TNtfkj

lklleats

π

( ) ( )( ) ( )∑ ∑−

=

−∆+++−

=

−

⋅⋅=1

0

21

0

2

,PRACH

ZC

CPRA21

0

ZC

ZC)(

N

k

TtfkKkjN

n

N

nkj

vu eenxtsϕπ

π

β

RBsc

DLRB

RBsc

DLRB

RBsc

PRB

RBsc

DLRBRB

sc

DLRB

RBsc

RBsc

PRB

RBsc

DLRB

RBsc

PRB

2

7for

12

6

2

6for

2

12

70for

NNkNN

N

kn

NN

kNN

N

Nkn

NN

kN

kn

⋅≤≤⋅+

=

−⋅+

≤≤⋅−

−=

−⋅−

≤≤

=

=

−− )(

)(

)()(

)(

)(

)1(

)0(

)1(

)0(

ix

ix

UiDiW

iy

iy

P υMM

[ ]Tjjju 2)1(2)1(16 +−−+=

2}1234{

0W

=

== ++−

+−

61,...,32,31

30,...,1,0)(

63

)2)(1(

63

)1(

ne

nend

nnuj

nunj

u π

π

( ) ( )

( ) ∑∑=

−∆−

−=

−∆ ⋅+⋅= +−

2/

1

2)(

,

1

2/

2)(

,

)(

RBsc

DLRB

s,CP)(

RBsc

DLRB

s,CP)(

NN

k

TNtfkjp

lkNNk

TNtfkjp

lk

pl

ll eaeatsππ

2RBsc

ULRB

RBscRA0 NNNkk −=


Orthogonal Frequency Division Multiplexing

…

Sub-carriersFFT

Time

Symbols

5 MHz Bandwidth

Guard Intervals

…

Frequency

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.


Why OFDM for the downlink?

• 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


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


OFDM vs. OFDMA

LTE uses OFDMA – a variation of basic OFDM

• OFDM = Orthogonal Frequency Division Multiplexing

• OFDMA = Orthogonal Frequency Division Multiple Access

• OFDMA = OFDM + TDMA

User 1

User 2

User 3

Subcarriers

Symbols (T

ime)

OFDM

Subcarriers

Symbols (T

ime)

OFDMA

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

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


LTE uses SC-FDMA in the uplink

Why SC-FDMA?

• SC-FDMA is a new hybrid modulation technique combining the low PAR

single 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.

DFT Sub-carrier Mapping

CP insertion

Size-NTX Size-NFFT

Coded symbol rate= R

NTX symbols

IFFT

Frequency domain Time domainTime domain


Comparing OFDM and SC-FDMA

QPSK example using N=4 subcarriers

The following graphs show

how this sequence of QPSK

symbols is represented in

frequency and time

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

15 kHzFrequency

fc

V

Time

OFDMA

symbol

OFDMA

symbol

CP

OFDMAData symbols occupy 15 kHz for

one OFDMA symbol period

SC-FDMAData symbols occupy N*15 kHz for

1/N SC-FDMA symbol periods

60 kHz Frequencyfc

V

Time

SC-FDMA

symbol

SC-FDMA

symbol

CP


OFDM modulation


1,1

+45°

-1,-1

+225°

-1,1 +135°

1,-1 +315°

f0(F cycles)

f0 + 15 kHz(F+1 cycles)



One OFDMA symbol period

…

…

…

…

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 four

carrier signal varies widely depending

on the symbol data being transmitted

With many

subcarriers the

waveform

becomes

Gaussian not

sinusoidalNull created by transmitting

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

1,1-1,1

1,-1-1,-1

I

Q


SC-FDMA modulation


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


The LTE air interface

• Consists of two main components – signals and channels

• Physical signals

• These are generated in Layer 1 and are used for system

synchronization, cell identification and radio channel estimation

• Physical channels

• These carry data from higher layers including control, scheduling and

user payload

• The following is a simplified high-level description of the

essential signals and channels.

• eMBMS, MIMO and some of the alternative frame and CP

configurations are not covered here for reasons of time


Signal definitions

DL Signals Full name Purpose

P-SCH Primary Synchronization Channel Used for cell search and identification

by the UE. Carries part of the cell ID

(one of 3 orthogonal sequences).

S-SCH Secondary Synchronization

Channel

Used for cell search and identification

by the UE. Carries the remainder of

the cell ID (one of 170 binary

sequences).

RS Reference Signal (Pilot) Used for DL channel estimation.

Exact sequence derived from cell ID,

(one of 3 * 170 = 510).

UL Signals Full name Purpose

RS (Demodulation) Reference Signal Used for synchronization to the UE

and UL channel estimation


Channel definitions

DL Channels Full name Purpose

PBCH Physical Broadcast Channel Carries cell-specific information

PDCCH Physical Downlink Control Channel Scheduling, ACK/NACK

PDSCH Physical Downlink Shared Channel Payload

UL Channels Full name Purpose

PRACH Physical Random Access Channel Call setup

PUCCH Physical Uplink Control Channel Scheduling, ACK/NACK

PUSCH Physical Uplink Shared Channel Payload


Signal modulation and mapping

DL Signals Modulation Sequence Physical Mapping Power

Primary

Synchronization Signal

(P-SCH)

One of 3 Zadoff-Chu

sequences

72 subcarriers centred

around DC at OFDMA

symbol #6 of slot #0

[+3.0 dB]

Secondary

Synchronization Signal

(S-SCH)

Two 31-bit M-sequences

(binary) – one of 170 Cell

IDs plus other info

72 subcarriers centred

around DC at OFDMA

symbol #5 of slot #0

Reference Signal (RS)OS*PRS defined by Cell

ID (P-SCH & S-SCH)

Every 6th subcarrier of

OFDMA symbols #0 & #4

of every slot

[+2.5 dB]

UL Signals Modulation Sequence Physical Mapping Power

Reference Signal (RS) uth root Zadoff-ChuSC-FDMA symbol #3 of

every slot


Channel modulation and mapping

DL Channels Modulation Scheme Physical Mapping

Physical Broadcast Channel

(PBCH)QPSK

72 subcarriers centred around

DC at OFDMA symbol #3 & 4 of

slot #0 and symbol #0 & 1 of slot

#1. Excludes RS subcarriers.

Physical Downlink Control

Channel (PDCCH)QPSK

OFDMA symbol #0, #1 & #2 of

the first slot of the subframe.

Excludes RS subcarriers.

Physical Downlink Shared

Channel (PDSCH)

QPSK, 16QAM,

64QAMAny assigned RB

UL Channels Modulation Scheme Physical Mapping

Physical Random Access

Channel (PRACH)QPSK Not yet defined

Physical Uplink Control

Channel (PUCCH)BPSK & QPSK

Any assigned RB but not

simultaneous with PUSCH

Physical Uplink Shared

Channel (PUSCH)

QPSK, 16QAM,

64QAM

Any assigned RB but not

simultaneous with PUCCH


Physical Layer definitions – TS36.211

Frame Structure

Ts = 1 / (15000x2048)=32.552nsec

Ts: Time clock unit for definitions

Frame Structure type 1 (FDD/TDD)

FDD: Uplink and downlink are transmitted separately

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

#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


Frame Structure Type 1 – generic view

Time

Frequency

1 radio frame = 10 msec (307200 x Ts)

#0

#1

#2

#3

#4

#5

#19

#18

#17

#16

Sub-frame

NBWDL subcarriers

NBWRB subcarriers (=12)

Power

The minimum allocation

of resources is one

Resource Block

= 12 adjacent

subcarriers for one

0.5ms slot

1 slot =

0.5 msec


Agilent Confidential

Page 36

Frame Structure Type 1 (DL)

Slot / Subframe / Frame

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 - Primary Synchronization Channel

S-SCH - Secondary Synchronization Channel

PBCH – Physical Broadcast Channel

PDCCH – Physical Downlink Control Channel

Reference Signal – (Pilot)

1 frame

1 sub-frame

1 slot

13 Aug 2007

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

0 1 2 3 4 5 6

#0 #1 #8#2 #3 #4 #5 #6 #7 #9 #10 #11 #12 #19#13 #14 #15 #16 #17 #18


Frame Structure Type 1 (DL) – Physical Mapping

Frequency

QPSK16QAM64QAM

P-SCH - Primary Synchronization Channel

S-SCH - Secondary Synchronization Channel

PBCH – Physical Broadcast Channel

PDCCH – Physical Downlink Control Channel

Reference Signal – (Pilot)

Time


Page 38

Frame Structure Type 1 (UL)

Slot / Subframe / Frame

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 #11 #12 #19#13 #14 #15 #16 #17 #18

1 frame

10 2 3 4 5 6

1 sub-frame

0 1 2 3 4 5 6


Frame Structure Type 1 (UL) – Physical Mapping

Frequency

Time

16QAM

Reference Signal

(Demodulation)

QPSK

64QAM


Agenda





• Simulation

• Baseband

• Sources

• Analysis

• Integrated mobile test platform


LTE development challenges

• Shortened time-plan for development and deployment

• Development in parallel with standards refinements

• Early requirement for full functional testing

• Interoperability testing likely to show up different interpretations of

standards

• Mix of FDD- and TDD-based testing

• System test for MIMO architecture

• Channel bandwidth up to 20MHz / 172.8 Mbps

• Component and device capabilities will be greater than network

capability

• Huge strain on mobile platform design


Crossing the Analogue-Digital divide


Tools & Using Them Together


Agilent’s Current Measurement Solutions and

Plans for LTE - Commitment

Agilent will provide design and test tools across the R&D

lifecycle

• Support for early R&D in components, base station

equipment and mobile devices with design automation tools

and flexible instrumentation, based on current measurement

platforms

• Refine test solutions and introduce tools for product

integration as development progresses to initial functional

prototypes

• Be ready with manufacturing test capability for early ramp-up


Integrated Mobile

Test platform

New Platform for

multiple serial lanes

LTE Products2006 2007 2008 2009 2010

3GPP LTE

UL/DL Signals

3GPP LTE UL/DL Analysis

and Demodulation

MIMO capability

ADS simulation

SW

Demod

Analysis SW

Signal

Generation

Signal

Analysis

Logic

Analysis

MIPI D_Phy

Commercial ReleasePrototype Versions

MXG

MXA

Basic Coded RT

DigRF

89601A VSAProto VSA


Page 46

ADS Wireless Library for LTE

Explore and verify your designs

• Current Status• Library of simulation components for the Agilent EESof Advanced

Design System (ADS) to facilitate the generation and analysis of

3GPP LTE compliant downlink (DL) and uplink (UL) signals.

• First release Oct 2006. Major updates in Feb 07, May 07, Sept 07.

• Based on latest physical layer specifications V8.0.0 *Sept 07).

• Generated signals are spectrally correct and encoded, and can be

multi-channel, fixed-length, real-time etc. as required.

• Signals can be exchanged with alternative simulation platforms, and

can be downloaded to, or uploaded from hardware for real-world

signal generation and analysis.

• Received signals can be demodulated and analyzed.

• Next Steps• Continue to follow developments in 3GPP specifications. Add/evolve

signal coding and further develop both DL and UL transmitter

measurements (such as EVM, Constellation etc.).

• Further commercial releases at regular intervals.

• Working on TDD support


Page 47

Advanced Design System Simulation environment

An LTE downlink model in ADS


Page 48

Example here is from IEEE 802.11a/g

ADS “Connected Solutions”

• Develop library elements for 3GPP LTE in order to build physical layer models for both transmitter and receiver in software

• Links to test equipment for prototype verification

• Implement and deliver a design tool while standard evolves phased implementation in close cooperation with customer

Download

Analyze

RF Component or DUT


Page 49

Digital Serial Stimulus / Analysis

• Current Status• Introduced DigRF v3 products and solutions

• Bridge gaps between simulation, IC evaluation & handset integration.

• The N4850A & N4860A digital probes designed for 1Gbps

• For LTE digital interfaces that > 1Gbps leverage existing multi GHz

serial technology to support higher speed interfaces.

• Agilent is a MIPI member at Adopter level.

• Next Steps• Support digital serial stimulus and analysis for

other RF-IC to BB-IC interfaces, integrated

with RF stimulus/analysis, to provide

comprehensive cross domain solutions.

• Review the physical layer specifications for

other (public and vendor-specific) interfaces

between the RF-IC and the BB-IC to guide

LTE specific implementation decisions.

• Agilent is committed to providing test tools for

DigRF v4.0.

N4850A 312Mbps DigRF v3 Digital Serial Acquisition Probe

N4860A 312Mbps DigRF v3 Digital Serial Stimulus Probe


Page 50

BB/RF Interface Stimulus / Analysis Overview

Two modes of operation

• Emulation: The stimulus and analysis pods

actively drive and terminate the BB/RF bus, thus

emulating the BB ASIC's interface. The test

equipment provides support for RF ASIC

configuration / control, and drives it with signal

payload data.

• Spying: The analysis pod passively monitors

the bus to collect data for further analysis. The

test equipment parses the traffic and presents

the transactions (XML-based protocol viewer)

and payload (89601A Vector Signal Analyzer).

BB ASIC

TEST EQPT(emulation)

RF ASIC

BB ASIC

TEST EQPT(spying)

RF ASIC


Page 51

RF-IC Validation (DigRF example)

89601A Vector Signal Analyzer software

RF-IC

Signal Studio Signal Creation Software

N4850AAcquisition Probe

N4860AStimulus Probe

Tx

Rx

16900Logic Analyzer

MXA Spectrum Analyzer

MXG Signal Generator


Page 52

RF-IC / BB-IC Integration (DigRF example)

DSPDigRF

v3.xx

89601A Vector Signal Analyzer

RF

Logic Analyzer Oscilloscope Spectrum Analyzer

RF

BB-IC RF-IC

MXG Signal Generator

Signal StudioSignal Creation Software

DigRF

uCDigRF

v3.xx

Vis Port

Digital


Page 53

LTE Signal Generation

Signal Studio Software

User-friendly, parameterized and reconfigurable 3GPP

LTE signal generation software for use in conjunction

with Agilent ESG-C or MXG RF Signal Generators.

Page 53

E4438C (ESGE4438C (ESG--C)C)

N5182A (MXG)N5182A (MXG)

• Current Status• Spectrally correct version available since April 07

• Fully coded version released recently

• Now based on TS 36.211 V8.0.0

– DL Physical channel framing

– Reference signal, Synchronization signal

– PDSCH, PDSCH, PDCCH, PBCH

– UL Physical channel framing

– Reference signal (Demodulation and Sounding)

– PUSCH, PUCCH, PRACH


LTE Signal Generation

N7624B Signal Studio V3.0.0.0 September 2007

Download now at: www.agilent.com/find/signalstudio

Just released Signal

Studio V3.0.0.0.

Build your own

custom LTE signals

Based on the latest

V8.0.0 (Sept 07)

LTE physical layer

specifications

RF playback

requires instrument

license (free 14-day

trial license

available)



Page 55

LTE Parametric Signal Analysis

13 Aug 2007Page 55


• Analyzes all LTE modulation types: BPSK,

QPSK, 16QAM, 64QAM, CAZAC, and

OSxPRS

• Covers all bandwidths: 1.4MHz (6RB) to

20MHz (96/100 RB)

• Handles UL and DL, normal and extended

Cyclic Prefix

• Advanced analysis of radio frame, subframe,

resource blocks, and channels

• Auto detection and demodulation of DL user

bursts

• P-SCH, S-SCH, PBCH, PDCCH, RS, PDSCH

and PUSCH analysis

• EVM = -50dB (measurement platform

dependent)


Page 56

LTE Signal Analysis

Downlink Capabilities (based on 36.211 V8.0.0)

• Synchronisation to ADS 2006U1(or U2).407 Dev 1

generated LTE Downlink signals

• Supports Antenna Port 0..3 RS pilot

subcarrier/symbol mappings per TS36.211 OS and

PN9 PRS

• Supports latest PSCH using ZC root indices 25, 29,

34 for cell ID Groups 0, 1, 2 respectively.

• Auto detect / report RS Orthogonal Sequence

• Auto detection of RS PRS

• Latest RS subcarrier antenna mappings

• PDCCH can occupy the first L OFDM symbols in

first slot of subframe, where L<=3.

• User can configure PDCCH symbol allocations on a

subframe-by-subframe resolution.

• Demod. user specified Slot# and OFDM symbol#

• User definition of up to 6 PDSCH 2D Data Bursts

for EVM analysis (format QPSK, QAM16, QAM64)

• Downlink frequency lock range approximately +/-

22.5kHz


Analyzing OFDM impairments using 89601A

• This downlink signals shows a common OFDM impairment where the allocated subcarriers have an image

• The distortion that create this image was 0.1dB IQ gain imbalance

• The lower trace shows the increased EVM at the image

• Requirements will be developed to limit the image

Allocation Image

EVM by subcarrier


Page 58

LTE Signal Analysis

Uplink Capabilities (based on 36.211 V8.0.0)

• Synchronisation to ADS 2006U1(or U2).407

Dev1 generated LTE Uplink signals

• Multiple resource block allocations restricted to

sub carrier DFT sizes which are multiples of 2,

3 and 5 as per current 3GPP working

assumption.

• The DM RS Pilot symbol is located in 4th

symbol (i.e. sym=3) of allocated slots.

• Demodulation of user specified SC-FDMA

symbol# within a Slot of Radio Frame

• Assumes DM RS Pilot symbol contains Zadoff-

Chu Sequence mapped to every subcarrier

within allocated contiguous RB size.

• User definition of PUSCH two-dimensional

Data Bursts for EVM analysis (format QPSK,

16QAM, 64QAM)

• Supports Half-Subcarrier-Shift = On/Off

• Uplink frequency lock range approx. +/- 7.5kHz


Page 59

LTE Signal Analysis - Measurements

• Sync Correlation

• Freq Error (Hz)

• IQ Offset (dB)

• EVM (%RMS and dB), EVM Peak

(%pk and sub carrier location)

• Data EVM (%rms and dB), EVM Peak


• Pilot EVM (%rms and dB), EVM Peak


• Common Pilot Error (%rms)

• Symbol Clock Error (ppm)

• CP Length

• Slot #, Symbol #

• Channel EVM table metrics

– Downlink supports P-SCH, S-SCH,

RS Pilot, PBCH, PDCCH, PDSCH

01 thru 06 (dB, %rms, %pk, Peak

Loc'n)

– Uplink supports DM Pilot, PUSCH

(dB, %rms, %pk, Peak Loc'n)

• Channel Power table metrics

– Downlink supports P-SCH, S-SCH,

RS Pilot, PBCH, PDCCH, PDSCH

01 thru 06 (dB relative to un-

boosted reference)

– Uplink supports DM Pilot, PUSCH

(dB relative to un-boosted

reference)


Page 60

LTE Signal Analysis – Trace views

• Channel Freq Response (Adj. Diff Mag Spectral Flatness,

Magnitude, Phase, Group Delay)

• Common Pilot Error (Magnitude, Phase)

• Differential Pilot Error (Timing)

• EVM Spectrum (composite EVM displayed per Sub-Carrier, or per Resource

Block)

• EVM Time (composite EVM displayed per OFDMA/SC-FDMA symbol)

• Power Spectrum (composite Power displayed per Sub-Carrier, or per Resource

Block)

• Power Time (composite Power displayed per OFDMA/SC-FDMA symbol)

• Symbol Demod IQ Constellation/Vector

• Symbol Demod Spectrum Magnitude

• Symbol Demod Time Magnitude

• Symbol Data (Demodulated symbol bits represented as two hexadecimal

characters per sub carrier)


Spectrum Analyzer HW platforms

• PSA with 40MHz or 80MHz analysis BW• Can be used as RF front end to external PC where

89601A VSA based LTE application is running

• MXA with 25MHz analysis BW• Can be used as RF front end to external PC where

89601A VSA based LTE application is running

• Since MXA is a windows product, the 89601A software

can run inside the instrument


LTE Integrated Mobile Test Platform

RLC/MAC interface for protocol test

Full LTE signalling stack

Protocol conformance test

GSM/GPRS, W-CDMA/HSPA

2x2 MIMO

Scalable single box solution

• 2G/3G/3.9G capable

• 20MHz BW

• 2x2 MIMO

• 2 cells

• RF parametric measurements

• Signalling Conformance Test

• RF Conformance Test

initial introduction: Mid-2008

Planned enhancements

RF conformance test

RF parametric measurements


In summary – Agilent & LTE

• Support for early R&D in components, base station equipment, mobile devicesand network deployment with design automation tools and flexible instrumentation, based on measurement platforms available today

Agilent will refine test

solutions and introduce

tools for product integration

as development progresses

to initial functional

prototypes.

Agilent will be ready with

manufacturing test

capability for early ramp-up

Agilent will provide the

tools needed for Service

Provider deployment

ADS

Software

Demod

Analysis SW

Signal

Generation

Signal

Analysis

Logic

Analyzer

AVAILABLE TODAY

* Used today for LTE development

* Commitment – LTE specific features

* Used today for LTE development

* Commitment – LTE specific Features

* Digital VSA tools available Today

Protocol

Analysis

Network

Optimization

Integrated mobile

test platform

AVAILABLE TODAY





Agilent LTE Brochure

5989-6331EN

www.agilent.com/find/lte

51090184 agilent lte

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