transmitter design based on the book: and measurement lte ... · pdf filelte rf design and...

© Agilent Technologies, Inc. 2009

LTE RF Design and Measurement Course

Based on the book:

LTE and the Evolution to

4G Wireless

Chapter 6.4

1 June 15-17, 2009

Transmitter Design and Measurement Challenges

4G World 2009

presented by:

David L. Barnerwww/agilent.com/find/4GWorld

Transmitter Design

and Measurement

Challenges



Agenda

Introduction / General & Overall Issues

Power & Spectrum Characteristics

Vector (Frequency & Time) Measurements

Analysis of Signals After Digital Demodulation

2 June 15-17, 2009




Agenda





3 June 15-17, 2009




General Challenges

• Variable & wide bandwidths – From 1.4 up to 20 MHz

• A new TX scheme for UL (SC-FDMA)

• FDD and TDD modes

• Stressful signal characteristics in terms of spectrum, power,

time variations due to traffic type and loading

• Multiple antenna techniques & MIMO

• The need for making complex tradeoffs between In-Channel,

Out-of-Channel and Out-of-Band Performance

4 June 15-17, 2009




A Systematic & Structured Approach

• When measuring complex signals, it is tempting to go directly

to advanced digital modulation analysis.

• However, it is usually more productive and efficient to follow a

verification sequence that begins with basic spectrum

measurements and continues with vector measurements,

before switching to modulation analysis.

5 June 15-17, 2009




Agenda





6 June 15-17, 2009





Familiar measurements apply for LTE:

• Channel power

• Occupied bandwidth

• ACLR

• SEM

• Center frequency, flatness

Initial verification and measurement of these can be made fairly easily via Spectrum Analysis

However, other power measurements can only be made via Vector Signal Analysis (demod)

7 June 15-17, 2009





• LTE’s wide bandwidth has interesting implications at allocated

spectrum band-edges

• Many LTE carriers will need to be at the edge of a band /

allocation

• This implies that many channels will be subject to Out-of-

Channel and Out-of-Band emission regulations simultaneously

• Out-of-Channel emissions can be made with ACLR/ACP and

SEM measurements

8 June 15-17, 2009





9 June 15-17, 2009


ACP Measurement



Agenda





10 June 15-17, 2009





• Average power measurements are not new, even for time-varying signals

• LTE also requires accurate power measurements down to the resource element level (1 symbol x 1 subcarrier), and on a selective basis

• New power / demod measurements such as in-band emissions and OFDM Symbol TX Power introduced

(next slide provides details from 36.141)

11 June 15-17, 2009





F.3.3 Resource Element TX power

Perform FFT (z’(ν)) with the FFT window timing. The result is called Z’(t,f). The RE TX power is then defined as:

From this the Reference Signal Transmit power (RSTP) is derives as follows:

It is an average power and accumulates the powers of the reference symbols within a sub frame divided by n, the number of reference symbols within a sub frame.

From RETP the OFDM Symbol TX power (OSTP) is derived as follows:

It accumulates all sub carrier powers of the 4th OFDM symbol. The 4th ,out of 14 OFDM symbols within a subframe, (using frame type 1 , normal CP length) contains exclusively PDSCH.

From the acquired samples, 10 values (per Frame) for each RSTP and OSTP can be derived.

KHzRETP 15|f)(t,Z| 2

subframewithinlocationsRERS

RETPn

RSTP1

subframewithinsymbolthoflocationsRENNall

RETPOSTP

4

RBsc

DLRB

12 June 15-17, 2009





• Power vs time measurements are of interest in LTE due to the varying structure of the signal (RS locations, channel locations, etc)

• Initially, these can be made without demodulating the signal, in order to verify absolute power levels using a VSA

• Wide BW LTE requires large Time Record Length (proportional to large number of FFT points)

• Example. 20MHz LTE @ 1Frame for 10ms requires 256,000 pt FFT

• CCDF behavior can also be measured – and in particular, using time-gating with a VSA

• NOT using time-gating significantly effects PAR during DTX (since lower average power)

13 June 15-17, 2009





14 June 15-17, 2009


Time Gate

Time Gating CCDF




Spectrogram allows us to interpret the overall signal at a glance

• It allows us to visually recognize major signal characteristics,

especially for complex signals such as DL

• Any serious power or frequency issues, for example of drift or

symbol transitions, will be visible here

15 June 15-17, 2009





PDSCH

PDSCH

PDSCH

PDSCH

RS

PDSCH

5 unallocated subcarriers on either side

of synch signals

Primary synch

signal

Secondary synch

signal

16 June 15-17, 2009


PBCH

Spectrogram of LTE DL



Agenda





17 June 15-17, 2009





• First we’ll focus on basic digital demodulation techniques

• Correct configuration in this step will help us properly verify

basic parameters and also give confidence when investigating

more intricate details of the signal

18 June 15-17, 2009





Measurement example for setup, including:

• FDD / TDD

• UL / DL

• Bandwidth & span

• Sync type

• Number of Antennas

• MIMO decoding

19 June 15-17, 2009





20 June 15-17, 2009


Measurement Example – LTE DL




21 June 15-17, 2009


Coupled Markers




22 June 15-17, 2009


Equalizer Impact

Without EQ

With EQ




Measuring EVM at different points in the CP

• EVM definition requires measurements be made at 2 different points in time during the CP

• VSA allows the designer to investigate the impact of time-domain distortion on the CP by changing the window length used to make EVM measurements

23 June 15-17, 2009




CP Len Nominal Symbol Len

FFT aligned with CP end

EVM is measured at two locations in time and

the maximum of the two EVM is reported. i.e.

EVM1 measured at EVM Window Start

EVM2 measured at EVM Window End

Reported EVM = max(EVM1, EVM2)

Agilent 89600 VSA EVM SettingFFT aligned with CP center

FFT aligned with CP start

Total Transmitted Symbol Len

Demodulation and Cyclic Prefix

EVM Analysis Windows (DL & UL)

24 June 15-17, 2009


If EVM vs Time gets noticeably better when selecting EVM window center, it could be due to high ISI coming from a baseband filter that is very tight (optimized for ACLR).




• Controlling the measurement interval allows detailed analysis

on very specific and precisely-chosen portions of the signal

• This allows measurement results to be isolated to certain

areas of trouble or interest

• Some terms are introduced to describe the timing and analysis

portions associated with the 89601 VSA (next slide)

25 June 15-17, 2009





Terms:

• Result Length

– Length (in slots) of acquired IQ used in analysis and aligned to Frame start boundary event

• Measurement Offset

– Delay offset (in slots or symbols) relative to Frame start boundary event and beginning of Measurement Interval

• Measurement Interval

– Measurement interval (in slots or symbols) ,starting from Measurement Offset, used for analysis

Note: Symbol by Symbol Resolution!

26 June 15-17, 2009





27 June 15-17, 2009

Transmitter Design and Measurement ChallengesSlot 0, Symbol 5 = S-SS + PDSCH




IQ errors: IQ image and LO leakage

• IQ distortion can be easily seen in the following example

resulting in mirror images about the center frequency using

spectrum and spectrogram displays

• An MXG Signal Generator can emulate IQ impairments

• LO Leakage = Adding MXG IQ Offset (via MXG front panel)

• IQ Image = Adding MXG IQ Gain Imbalance (via MXG front panel)

28 June 15-17, 2009





29 June 15-17, 2009


IQ Imbalance Impact



Summary

• LTE adds new complexities for transmitter design and test.

• More than ever, it’s imperative to have a structured and

systematic approach to signal test.

• Considered measurements made with an eye to

troubleshooting, and cause vs effect, will bring benefits to the

design and test engineering community.

31 June 15-17, 2009




Based on the book:

LTE and the Evolution

to 4G Wireless

Chapter 6.5

32 June 15-17, 2009


4G World 2009

presented by:

David L. Barner

Receiver Design and

Measurement

Challenges



Key Objectives

June 17-18, 200933

• Understand SISO RX test challenges

• Understand Agilent SISO solutions available to

address RX test challenges

June 17-18, 200933

Receiver Design and Measurement Challenges



Key LTE FDD eNB Test Challenges

LTE Conformance Tests Require Sophisticated Signals

• Various modulation bandwidths (1.4 MHz to 20 MHz)

• Various modulation types (QSPK, 16QAM, 64QAM)

• Transport channel coding with specific configurations, i.e. Fixed Reference Channels (FRC)

• Interfering Signals

• AWGN

• Emulation of channel propagation conditions

New Conformance Tests Require Special Test Configuration

• Three performance requirements tests require dynamic changes in signal characteristics

• Closed loop control of RV index based on HARQ feedback

• Closed loop control of RF frame timing based on TA feedback

• Interference and Rx diversity tests require MIMO-like test configurations



eNB Receiver Conformance Tests

Receiver characteristics

• Reference sensitivity level

• Dynamic range

• Adjacent Channel Selectivity (ACS)

• Blocking characteristics

• Intermodulation characteristics

• In-channel selectivity

• Spurious emissions

Note: UE conformance tests are still being defined

Solving test needs:

Flexibility to easily create varying signals that simulate real-world conditions

Signal generation capability that evolves as the standard evolves to ensure

most accurate test results

Performance Requirements• Performance requirements for PUSCH

• Multipath fading propagation conditions

• UL timing adjustment

• HARQ-ACK multiplexed on PUSCH

• High speed train conditions

• Performance requirements for PUCCH

• ACK missed detection for sing user PUCCH format 1a

• CQI missed detection for PUCCH format 2

• ACK missed detection for multi user PUCCH format 1a

• Performance Requirements for PRACH

•These test are performed open loop

•Performance metric = BLER

•These tests require HARQ feedback

•Performance metric = throughput

June 17-18, 200935




Receiver Characteristics Wanted Signal Interfering Signal Dynamic Range(wanted interferer)

Agilent Solution

7.2 Reference Sensitivity LevelFRC A1-1, 1-2, 1-3

QPSK ModNone required for this test -- Signal Studio & MXG

7.3 Dynamic RangeFRC A2-1, 2-2, 2-3

16QAM ModAWGN 12.4 dB Signal Studio & MXG

7.4 In-Channel SelectivityFRC 1-2, 1-3, 1-4, 1-5

QPSK ModE-UTRA with all BW 21.5 dB Signal Studio & MXG

7.5 Adjacent Channel SelectivityFRC A1-1, 1-2, 1-3

QPSK Mod

E-UTRA

Offsets up to 2.5 MHz*48.1 dB Signal Studio & MXG

7.5 Narrowband BlockingFRC A1-1, 1-2, 1-3

QPSK Mod

E-UTRA

Offsets up to 4.66 MHz*51.1 dB Signal Studio & MXG

7.6 Blocking

(in-band)

FRC A1-1, 1-2, 1-3

QPSK Mod

CW or E-UTRA

Offsets up to 7.5 MHz*57.1 dB Signal Studio + MXG + PXB

7.6 Blocking

(out-of-band)

FRC A1-1, 1-2, 1-3

QPSK Mod

CW

Offsets up to 12.75 GHz85.1 dB Signal Studio & MXG + PSG

7.6 Blocking

(Co-location with other base stations)

FRC A1-1, 1-2, 1-3

QPSK Mod

CW

Freq from 728 MHz to 2690 MHz116.1 dB Signal Studio & MXG + MXG

7.7 Receiver Spurious Emissions NA NA NA MXA Spectrum Analyzer

7.8 Receiver IntermodulationFRC A1-1, 1-2, 1-3

QPSK Mod

CW offset up to 7.5 MHz* &

E-UTRA offset up to 18.2 MHz*48.1 dB Signal Studio & MXG + PXB

7.8 Receiver Intermodulation

(Narrow Band Intermodulation)

FRC A1-1, 1-2, 1-3

QPSK Mod

CW offset up to 415 kHz* &

E-UTRA offset up to 1780 kHz*48.1 dB Signal Studio & MXG + PXB

Notes

• * from channel edge of wanted signal

• Either ARB or real-time Signal Studio can be used

• Tests do not require channel emulation

• Test are performed open loop, i.e. no HARQ or timing adjustment feedback required

Agilent 3GPP LTE eNB Test SolutionseNB Conformance Tests – Receiver Characteristics



Agilent 3GPP LTE eNB Test SolutionseNB Conformance Tests – Performance Requirements

Performance Requirements Wanted Signal Channel ModelChannel

ConfigurationFeedback

Agilent

Solution

8.2.1 PUSCH in Multipath Fading

Propagation Conditions

FRC A3, A4, A5

QPSK, 16QAM, 64QAM

EPA 5 Hz

EVA 5, 70 Hz

ETU 70, 300 Hz

1x2 (2x RX diversity)

1x4 (4x RX diversity)HARQ Real-time

8.2.2. UL Timing Adjustment

FRC A7, A8

QPSK & 16QAM

(SRS is optional)

Moving Propagation Model

a. ETU 200 Hz

b. AWGN



(Stationary & moving UE)

HARQ &

timing adjustment

Real-time +

Waveform Playback

8.2.3 HARQ-ACK Multiplexed on

PUSCH

FRC A3-1, A4-3 to A4-8

QPSK, 16QAMETU 70 Hz 1x2 (2x RX diversity) -- Waveform Playback

8.2.4 High Speed Train Conditions

FRC A3-2 to A3-7

QPSK

(PUCCH is optional)

High Speed Train with:

a. Open Space

b. Tunnel for multi-antenna


1x4 (4x RX diversity)HARQ Real-time

8.3.1 ACK Missed Detection

for Single User PUCCH Format 1aPUCCH ACK

EPA 5 Hz

EVA 5, 70 Hz

ETU 70, 300 Hz


1x4 (4x RX diversity)--

Real-time or

Waveform Playback

8.3.2 CQI Missed Detection

for PUCCH Format 2PUCCH CQI ETU 70 Hz


1x4 (4x RX diversity)--

Real-time or

Waveform Playback

8.3.3 ACK Missed Detection

for Multi User PUCCH Format 1aPUCCH ACK ETU 70 Hz


(Requires 3 interferers)-- Waveform Playback

8.4.1 PRACH False Alarm

Probability and Missed DetectionPRACH Preamble

ETU 70 Hz

AWGN (no fading)


1x4 (4x RX diversity)-- Waveform Playback

Notes

• All tests require channel emulation and AWGN

• All tests require RX diversity if supported by eNB

• Industry is requesting up to 4-way RX diversity for all tests, i.e. 1x4, 2x4, & 4x4 MIMO

• Agilent Solution indicates type of Signal Studio for 3GPP LTE FDD software. N5106A PXB MIMO receiver tester and N5182A MXG vector signal

generator are also required.



Page 38

Agilent 3GPP LTE Test Solutions Rx RF/BB Front End Verification

Generate simple test signals

• Create CW signals

• Create multi-tone signals

Generate simple LTE signals

• Ultimate physical layer flexibility

• Supports March 09 version of LTE standard

• Selectable BW from 1.4 MHz to 20 MHz

• Select PUSCH modulation: QSPK, 16QAM, 64QAM

• Configurable data payloads

• Allocate resource blocks in frequency & time

Measure basic RF parameters

• Analyze amplitude flatness

• Measure gain at each stage

• Analyze phase linearity

• Determine noise figure

• Measure EVM of components & subsystems

Signal Studio- Uplink FDD LTE

- ARB basic capability

MXG Vector Signal Generator Receiver Front End

MXA Signal Analyzer

Analog I/Q,

Digital I/Q,

DigRF

RF



Page 39

Agilent 3GPP LTE Test Solutions Rx Conformance Test

Real-time LTE Signal Generation

• PXB accepts closed loop feedback

• HARQ ACK/NACK signals

• Timing adjustment feedback

• LTE signal continuously adjusted based on feedback

• Predefined Fixed Reference Channel definitions

Real-time Channel Emulation

• Standards based channel models

• Custom defined channel models

• 24 paths of fading

• 120 MHz modulation bandwidth

• Simplified power calibration

Interfering Signals

• Add CW blocking signals

• Add modulated signals for blocking &interoperability test

• Calibrated AWGN for accurate C/N ratios

RF

Digital I/Q

Feedback

Signal StudioUplink FDD LTE

Real-time capability

eNBPXB MIMO Rx Tester

MXG Vector Signal Generator



Page 40

Agilent 3GPP LTE Test Solutions RF/BB Channel Emulation

Advanced Channel Emulation

• 120 MHz fading bandwidth

• 24 paths of fading per channel

• Up to 8 independent fading channels

• Custom MIMO correlation settings

• Configurable antenna parameters

• Standards based channel models


• RF to RF fading with MXA

Simplified Signal Routing & Summing

• Combine independent channels for diversity or MIMO

• Windows operating system

• Intuitive GUI

Scalable Architecture

• Connect to ESG, MXG, & DSIM for signal creation

• Connect to MXA for RF fading applications

• Field upgradable with calibrated DSP blocks

Signal StudioMXG Vector Signal Generator

PXB MIMO Rx Tester

00h

01h

Tx0 Rx0

Rx1

RX Diversity



Page 41

Agilent 3GPP LTE Test Solutions RF/BB Interference and Interoperability Test

Configuration flexibility

• Create: LTE, W-CDMA/HSPA, GSM/EDGE, cdma2000,

1xEV-DO, WiMAX, WLAN …

• Up to four internal baseband generators

• Sum CW carriers with wanted signal

• Sum modulated carriers with wanted signal

• Sum custom Matlab waveforms with wanted signal

• Add calibrated AWGN for accurate C/N ratios

Scalable Test Solutions

• Tailor capability & performance from SISO to MIMO

• Easily upgrade as your test needs evolve

• Connect to ESG, MXG, & DSIM for signal creation

• Connect to MXA for RF fading applications

• Field upgradable with calibrated DSP blocks

High Performance

• Real-time uplink FDD LTE signal creation

• Real-time MIMO channel emulation


• Wide bandwidth – ready for LTE Advanced (Rel 10)

PXB MIMO Rx Tester Interoperability testing

0

Signal StudioMXG Vector Signal Generator



PXB Closed Loop Test ConceptHARQ & Timing Adjustment Tests

10MHz

HARQ ACK/NACK

Digital I/Q

Baseband w/ Fading

10MHzLAN

GPIB

Frame Pulse

Signal Studio

N7624B 3GPP LTE FDD

eNB

RF

Throughput Testing Equipment Configuration

N5182A MXG

N5106A PXB

Timing Adjustment

CMOS 3.3 V inputs from eNB

•HARQ – Level Triggered

•Timing Adjustment – Serial Data

Dynamically Changing RF

•Frame Timing based on TA

•RV Index based on ACK/NACK



Timing AdjustmentConformance Test Concept

Moving UE simulates changing propagation path lengths

In this example, the mobile UE is assigned blue Resource Blocks

Stationary UE

eNB Frame Timing

1 symbol (2048·Ts)

Normal Cyclic Prefix

Res

ou

rce

Blo

ck

s

Moving UE signal can arrive at wrong eNB frame timing as path length changes

UE transmission interferes with next symbol without timing adjustment

Details

• Stationary UE and moving UE transmit in same

subframe, but with different subcarriers

• Moving UE simulates changing propagation path

lengths & therefore different arrival times at eNB

• eNB must command moving UE to advance or delay

timing of transmission such that the signal arrives at

eNB with proper frame timing, i.e. does not overlap into

adjacent symbols

• Timing adjustment test is performed with even

subfames occupied

• Sounding Reference Signal (SRS) is optional for this

test

• This test is performed with real-time HARQ feedback

eNB

Timing Adjustment transmitted back to

UE, to align UE with eNB frame timing



Common RF Front End MeasurementsAmplitude Flatness

June 17-18, 200944

Issues

• LTE can correct some amplitude / phase

errors with RS

• Errors will manifest themselves as EVM

• Important because LTE BW is wider than

other cellular standards

• Need to test individual components, i.e.

Amplifiers, Filters, Mixers, etc

How to test

• LTE signals could be used

– Some configurations of LTE do not utilize

all subcarriers

– Power not constant over LTE BW

• Alternate approach with multitone signals

– Space tones over BW of interest

– Correction techniques enable flatness of

~0.1 dB

Signal Studio for Multitone Distortion

June 17-18, 200944





June 17-18, 200945

Amplitude Flatness Test Calibration Configuration

MXG Signal Generator

MXA Signal Analyzer

10 MHz ReferenceLAN

RF Input

RF Output

Signal Studio for

Multitone Distortion DUT

June 17-18, 200945


Additional Benefit:

Entire System is calibrated!




June 17-18, 200946

Multitone Performance with Corrections

• 50 Tones

• Spaced over 100 MHz

Before Corrections After Corrections

Note: Scale per div is 0.2 dB in each graph Corrected flatness is ~ 0.1 dB!

June 17-18, 200946




Common RF Front End MeasurementsPhase Linearity

June 17-18, 200947

Issues

• LTE can correct some amplitude / phase

errors with RS

• Errors will manifest themselves as EVM

• Important because LTE BW is wider than

other cellular standards

• Need to test individual components, i.e.

Amplifiers, Filters, Mixers, etc

How to test

• Can’t measure phase w/ Spectrum Analyzer

• High degree of integration may make

network analyzer impractical

• VSA can measure Amplitude flatness and

also Phase linearity of modulated LTE signal

MXG + 89601A VSA Measurement

June 17-18, 200947


Ampl. Flatness

Phase Linearity



RF-IC

DigRF

Common RF Front End MeasurementsAnalog-to-Digital Converter

MXG Signal Generator

Digital Stimulus / Analysis

89601A VSA Software

Signal Studio for 3GPP LTE

Issues

• Analyzing data in digital domain

How to test

• Modulated LTE stimulus

• Use Logic Analyzer or DSIM/ESG with 89601 VSA

June 17-18, 200948


Digital I/Q DSIM

N5102A



Common RF Front End Measurements

June 17-18, 200949

Other Things to Consider…

• Automatic Gain Control (AGC)

• Noise Figure

• Receiver Error Vector Magnitude

• Receiver Performance under Impaired

Conditions…

June 17-18, 200949




Receiver Performance under Impaired Conditions-Phase Noise Impairments

June 17-18, 2009

• LTE subcarrier spacing is 7.5 kHz or 15 kHz

• Close subcarrier spacing makes RX highly susceptible to phase noise problems

• Results in degraded EVM

• Signal generator can be used as LO, but typically have much better phase noise than

RX

• N5182A phase noise characteristic an be degraded very precisely

– Determine performance required for LO in RX

– Determine performance of RX with impaired signal from TX

“Pedestal” set to -90 dBc

June 17-18, 200950




June 17-18, 2009

Pedestal Phase Noise Set at

-90 dBc/Hz

MXG non-impaired phase

noise characteristic at -116

dBc/Hz

N5182A MXB Phase Noise Plots

(w and w/o Phase Noise Impairments)

June 17-18, 200951



~26 dBc/Hz



June 17-18, 2009

Phase noise characteristic with

pedestal set at -90 dBc/Hz

Two Carriers Spaced at 15 kHz (w and w/o Phase Noise Impairments)

MXG noise floor

June 17-18, 200952



~26 dBc/Hz



June 17-18, 2009

EVM has increased from less

than 0.5% to more than 6%

EVM degradation due to added Phase Noise

impairment at -90 dBc/Hz

June 17-18, 200953



Note:

Constellation appears

more Gaussian than

expected rotation.

Why?



June 17-18, 2009

5 MHz LTE signal with 20

MHz AWGN at 30 dB C/N

LTE Signal with AWGN

June 17-18, 200954


Receiver Performance under Impaired Conditions-AWGN Impairments

Although specified, is

not a real representation

of actual interference

due to NB allocations

used in OFDM systems

-Just a simplified model!

-Better for CDMA



June 17-18, 2009

Many Systems employ IQ Demoduators

Typical impairments

• I/Q DC offsets, IQ Quadrature Phase

• I/Q Gain Imbalance

• I/Q Skew (Delay)

Issues

• Creates LO feedthrough

• Creates unwanted images

• Results in degraded EVM (Classic “V”)

Can add with signal generator

• Compensate for errors in RX

• Determine impact from TX

LTE Signal w/ IQ impairments

Image

LO

Feedthrough

Original signal

(offset +30 MHz)

June 17-18, 200955


Receiver Performance under Impaired Conditions-IQ Impairments



June 17-18, 2009

LTE signal with 5 ns skew between I & Q

•EVM decreases from

0.5% to ~2%

•More noticeable in

EVM vs subcarrier

June 17-18, 200956


Receiver Performance under Impaired Conditions-IQ Impairments

Classic “V”:

Timing error gets

progressively worse

as subcarriers get

farther away CF



June 17-18, 2009

• Can receiver correctly reject interfering carriers?

• Selectivity tests

• Blocking tests

• IMD immunity tests

W-CDMA LTE

June 17-18, 200957


Receiver Performance under Impaired Conditions-Interference

Multi-Carrier output from single MXG

Note:

Don’t require multiple

Sig Gens, power combiners,

or isolators!



June 17-18, 2009

Propagation Conditions’ three major components:

• Delay spread (Amplitude / phase fluctuations) – result of multipath profile

• Doppler spreading – result of TX or RX movement

• TX/Rx Antenna Correlation Matrix

Amplitude fluctuations as a function of time

Deep Fade

~ 40dB!

June 17-18, 200958


Receiver Performance under Impaired Conditions-Fading



June 17-18, 2009

Effect of Amplitude and Phase changes on a QPSK constellation

QPSK modulated carrier faded with two paths of Rayleigh fading

June 17-18, 200959


Receiver Performance under Impaired Conditions-Fading



Baseband Measurements

Tools for Creating RF-RF Faded Signals

June 17-18, 2009


60

Page 60

RF

Analog I/Q- Direct from PXB

- Connect to any DUT or RF

vector signal generator

with analog I/Q inputs

RF

Digital I/Q

Signal OutputsSignal Inputs Signal Creation Tools

ESG or MXGPXB

MXA

N5102A

Page 60

Agilent Restricted

June 17-18, 200960




Questions?

“Excuse me, is this the Society for

Asking Stupid Questions?”

www/agilent.com/find/4GWorld



Backup

June 17-18, 200962


transmitter design based on the book: and measurement lte ... · pdf filelte rf design and...

Documents