mmwave mimo channel sounding for 5g — technical … with parameters such as path loss, delay,...

5G mmWave MIMO Channel Sounding Technical Challenges and Test Approaches

Sheri DeTomasi

5G Solutions

Program Manager

Sept 2015

Page Page Topics

– Channel sounding fundamental

– Channel sounding approaches

– 5G Channel sounding technical challenges

– 5G channel sounding measurements

– Summary

Keysight 5G

Channel Sounding 2

Page © 2015 Keysight Technologies

1 GHz 10 GHz 100 GHz 1 THz 10 THz 100 THz 1PHz

10 cm 1 cm 1 mm 100 mm 10 mm 1 mm

Wavelength

Frequency Microwave THz Far IR Infrared UV

5G Goals and Key Performance Indicators

Keysight 5G

Channel Sounding

mm-Wave

100X Energy

Efficiency

Reliability

99.999%

1mS Latency

100X

Densification

1000X

Capacity

100X Data

Rates 5G air interface technology investigations

• mmWave channels

• Waveform design

• Massive MIMO

• Full duplex

Channel behavior is not well understood

for mobile multiple-access

communications at mmWave. Channel

sounding is needed to characterize new

potential 5G air interfaces

Amazingly fast

Great service in a crowd

Super real-time &

reliable communications

Ubiquitous “things”

communicating

New

Market Demands

3


What is Channel Sounding?

The RF channel is the heart of any radio-communication system and must be

characterized with parameters such as path loss, delay, absorption, reflection,

multipath, fading, Doppler, all which can affect the performance of the overall system

Channel sounding is required to understand the characteristics of RF channel

Tx Rx

Channel

𝑥 𝑡 𝑦 𝑡

ℎ 𝑡

𝑅𝑥𝑦 𝜏 = 𝐸 𝑥∗ 𝑡 𝑦 𝑡 − 𝜏

= ℎ(𝑡 − 𝜏) ⊗ 𝑅𝑥 𝜏

≈ ℎ 𝑡 − 𝜏 ⊗ 𝛿 𝜏 = ℎ 𝑡

* RF: Radio Frequency

𝒚 𝒕 = ℎ(𝑡) ⊗ 𝑥(𝑡)

Received Signal convolution

h(t) CIR extraction requires post or real-time signal processing

like using cross correlation processing technique here in this formula

CIR

Channel Impulse Response

Keysight 5G

Channel Sounding 4


Driving, impacting the overall R&D

• Antenna design SISO, MIMO, ARAY

• Power Amplifier & Receiver

• BB Signal Processing & Algo.

• Form factor

• Material

Channel Sounding Contribution in Wireless System Design

Keysight 5G

Channel Sounding

RF

Channel

Wireless

Communication system

CIR Measurement (using channel sounding)

Channel Modeling

Channel Emulation &

Simulation

Channel Related Research

Channel

Parameters

Channel Models

RAN

UEs

5


The Role of Channel Modeling

Keysight 5G

Channel Sounding

The many inputs to developing a channel model

6


Channel Sounding Contribution in Wireless System Design

Keysight 5G

Channel Sounding 7

Page Page Topics





– Summary

Keysight 5G

Channel Sounding 8


How can Channel Sounding be Implemented? Sounding Approach & Architecture

Sliding Correlator

• Low measurement speed

• Some only have amplitude information

Frequency Swept

• Low measurement speed

• Amplitude/phase information

Wideband Correlation

• Fast measurement speed


Sounding Techniques

Keysight 5G

Channel Sounding 9


How can Channel Sounding be Implemented?

Keysight 5G

Channel Sounding

Switching @ Tx & Rx

• Slowest measurement speed

• Serial measurement requires stable measurement environment

• No need for phase coherence

• No cross-interference

Switching @ Tx & parallel receive


• Multi-channel phase coherence needed in Rx


Parallel transmit & receive

• Fastest measurement speed

• Multi-channel phase coherence needed in Tx&Rx

• Suffering cross-interference

Most research has been SISO

5G requires MIMO characterization to include spatial information

10

Page Page Topics





– Summary

Keysight 5G

Channel Sounding 11


Key Requirements for 5G Channel Sounding

5G Key Requirements

mmWave Frequency Band

Ultra-broad Bandwidth

Massive MIMO

Keysight 5G

Channel Sounding

New 5G

Channel Models

12


Technical Challenges

Keysight 5G

Channel Sounding

Goal: Understand characteristics of new RF

Channels in mmWave Technical Challenges

1. Sounding approach & architecture

2. Signal generation and capture

- mmWave frequency band

- Ultra-broad bandwidth

- Multi-channel

3. Data capture & storage

4. Channel parameter estimation

processing

5. Calibration and synchronization of

the measurement system

Tx Rx

RF Channel

𝑥 𝑡 𝑦 𝑡

ℎ 𝑡

28 GHz, 38 GHz, 72 GHz

BW 500 MHz, 1 GHz, 2 GHz

Measurements:

• Path loss, absolute path delay,

power delay profile (PDP)

• AoA / AoD

• Doppler Shift

13


Consideration on 5G Channel Sounding

Keysight 5G

Channel Sounding

1. Sounding Approach & Architecture

Sliding Correlator

• Low meas. speed

• Amplitude information only

Frequency Swept

• Low meas. speed


Wideband Correlation

• Fast meas. speed


Switching @ Tx & Rx

• Slowest


Switching @ Tx, Parallel Receive

• Fast


Parallel Transmit & Receive

• Fastest

• Adds cross-interference

Sounding Techniques

MIMO Sounding Approaches

14



Keysight 5G

Channel Sounding

1. Sounding Architecture

Advantages


• MIMO sounding capability

• High measurement performance

• Arbitrary sounding waveform support

Keysight recommended sounding

architecture

Use wideband

signal generation

and analysis

Use switched Tx and

parallel Rx

15



Keysight 5G

Channel Sounding

2. mmWave, Ultra-broad Bandwidth, MIMO

Wideband Signal Generator Wideband Multi-channel Receiver

Wideband AWG1

mmWave Vector

Signal Generator

Wideband Multi-

channel Digitizer

mmWave Multi-

channel

Downconverter

mmWave Switch

mmWave

Signal

Wideband I/Q

Signal

mmWave

Sounding

Signal

Channel

IF Signal

1AWG: Arbitrary Waveform Generator

mmWave

Antenna

mmWave

Antenna

16



Keysight 5G

Channel Sounding

3. Data Capture & Storage

Sounding

signal

CIR1

Transmitting period 𝑇𝑝

Effective

CIR Data

Max. delay

spread 𝑇𝑑

Transmitting signal

length 𝑇𝑠

Raw Sounding Data 32GB/s 2

Effective Raw Data

1 CIR: Channel Impulse

Response 2 1GSa/s sampling rate,

𝑇𝑝 = 100𝑢𝑠, 𝑇𝑠 = 20𝑢𝑠, 𝑇𝑑 = 5𝑢𝑠

Effective Raw Data 8GB/s 2

1.6GB/s 2

Real-time data analysis reduces memory and

disk space requirements

17



Keysight 5G

Channel Sounding

4. Channel Parameter Estimating Algorithms

SystemVue

18



– The various channel parameter estimation algorithms can be categorized

with 3 types

• Beamforming Based: simple, but poor performance

• Subspace Based: good performance, but limit on the detected

number of paths

• Maximum likelihood based: widely used due to high performance and

strong capability

– ML Based SAGE: Space-Alternating Generalized Expectation

maximization

• High accuracy

• No limit on the maximal estimating path number

• Joint channel parameter estimation: Path, Delay, Doppler, AoA/AoD

Keysight 5G

Channel Sounding

4. Channel Parameter Estimating Algorithms

19



Synchronization

- Precise timing thorough GPS

clocks and triggering

System-Wide Calibration

- System impulse response

- IQ imbalance

- Multi-channel amplitude,

phase, delay

- System delay

- Power

- Antenna

Wideband Signal Generator Wideband

Multi-channel

Receiver

Wideband AWG1

mmWave VSG2 mmWave Multi-

channel DC3

Rubidium

Clock

Rubidium

Clock

I/Q Mismatch

Calibration

AWG

Acquisition

Trigger

Wideband Multi-

channel Digitizer

Channel Parameter

Estimation Algorithm

5. Synchronization and Calibration

Keysight 5G

Channel Sounding 20


Synchronization and Calibration Requirements for Wideband Sounding System

Measurement

Matrices

Synchronization & Calibration

LO

sync

Signal

Gen&Acq.

sync

Multi-ch

phase&amp

cal

System

IR cal

Antenna

cal

System

power

cal

System

delay cal

AWG

I/Q cal

SISO PDP(relative

delay) Yes Yes Yes

PDP (absolute

delay) Yes Yes Yes Yes Yes

Doppler freq. Yes Yes Yes Yes

MIMO PDP(relative

delay) Yes Yes Yes

PDP(absolute

delay) Yes Yes Yes Yes Yes

Doppler freq. Yes Yes Yes Yes

AoA/AoD

using antenna

array

Yes Yes Yes Yes Yes Yes

Keysight 5G

Channel Sounding 21

Page Page Topics





– Summary

Keysight 5G

Channel Sounding 22


Channel Sounding Measurements

CIR (Channel Impulse Response)

• PDP (Power Delay Profile): path delay, path loss

• AoA/AoD (Angle of Arrival/Departure)

• Doppler shift

Instant parameters

• AS (Angular Spread) of AoA/AoD

• PAS (Power Angular Spectrum)

• Doppler spectrum

• Correlation matrix

• Rician K factor

Statistics parameters & modeling

Keysight 5G

Channel Sounding

Tx Rx

RF Channel

𝑥 𝑡 𝑦 𝑡

ℎ 𝑡

28 GHz, 38 GHz, 72 GHz

23


Measurement System

Keysight 5G

Channel Sounding

Keysight 5G Channel Sounding Reference Solution

Software

System

Data capture and

storage IO control software

for calibration and synchronization

Transmitter

Config&Control

Receiver

Config&Control

RT autocorrelation of CIR

in FPGA

Parameter Estimation

Algorithm

Channel

Measurement

Results

M9703A, 1 GHz BW,

interleaving

N5173B 40 GHz LO

10MHz GPS

Ref Clk

E8267D PSG with

IQ inputs

M8190 2GHz BW

10MHz GPS

Ref Clk

33511A AWG for

Sync Trigger

M9362A-D01 40 or 50 GHz

Down Convertors

1x

4 o

r 1

x8

Sw

itc

h

Ch

an

nel

1x

4 o

r 1

x8

MIM

O

Signal generation

and capture

Up to 44 GHz

Up to 1 GHz BW

Up to 8x8 MIMO

24


Channel Sounding Signal Processing

Transmitter Receiver Channel

Sounding

Signal@TX

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000-1.5

-1

-0.5

0

0.5

1

1.5

Received Signal

(huge amount of

data)

Cross-correlator &

data truncation

(Real-time pre-

processing in

M9703A FPGA)

CIR

(greatly reduced

amount of data)

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 100000

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0 50 100 150 200 250 300 350 4000

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Processing

Algorithms

(SAGE, ESPRIT,

etc.)

Extracted

Channel

Parameters

Sounding

Signal@RX

Post-

processing

by user

Effective data

length is much

shorter than

receive signal

25

Keysight 5G

Channel Sounding


1 Channel Parameter Estimations in Keysight SystemVue

3

Block diagram of the actual

measurement setup 2

Setting options before the post processing of measurement parameter

– CIR/AoA/AoD/Dopppler frequency/Pathdelay/Pathloss

4

Measurement

Parameters

5G Channel Sounding Measurements

Keysight 5G

Channel Sounding 26


MIMO 8x8 Dual Polarization: 5.8GHz

– Waveform

– PDP

Keysight 5G

Channel Sounding 27

– Multiple Path Parameter

– Mirror Spectrum = NO


MIMO 8x8 Dual Polarization: 5.8GHz

– PDP V

Keysight 5G

Channel Sounding 28

– Multiple Path Parameter

– Mirror Spectrum = NO


5 Result Display of Measurement Parameters


Keysight 5G

Channel Sounding 29



Keysight 5G

Channel Sounding

4x4 mmWave MIMO Channel Sounding

Transmitter Receiver

– 4x4

– CF: 28GHz

– BW: 1GHz

– Size: 2 mobile carts,

838mm(L)*585mm(W)*92

0mm(H) for each

– Power consumption: Tx

~1KW; Rx~800W

30



Keysight 5G

Channel Sounding

90 GHz SISO System

M8190 5GHz

BW AWG

Rubidium

Clock

N5173B

LO

Rx

PA LNA BPF

Rubidium

Clock

AWG

E8267D

N9029AVxx-UDC

Tx N9029AV10 SA

frequency extension

module

15GHz Input

1~5GHz IF Output

31

http://s7.images.keysight.com/s7viewers/flash/genericzoom.swf?logo2=false&serverUrl=/is/image/&contentRoot=/skins/&locale=en&config=Keysight/KEYSIGHT-IMGSET&image=Keysight/PROD-1910360-IS

http://www.keysight.com/zh-CN/pc-1454469/systemvue-libraries-blocks?nid=-34259.0&cc=CN&lc=chi

Page Page Topics





– Summary

Keysight 5G

Channel Sounding 32


5G Channel Sounding Summary

Keysight 5G

Channel Sounding

- Channel sounding and modeling is critical in 5G research

- Key technical challenges need to be resolved to produce accurate

and repeatable results

33

1. Sounding approach & architecture

2. Signal generation and capture

- mmWave frequency band

- Ultra-broad bandwidth

- Multi-channel

3. Data capture & storage

4. Channel parameter estimation

processing

5. Calibration and synchronization of

the measurement system

1. Wide-band correlation with MIMO capability to

extract spatial parameters

2. Use metrology grade test equipment that has

sufficient frequency, sample rate, resolution,

and has support for multi-channel

3. Decimate data or use real-time processing for

better data management

4. Choose algorithm that provides good channel

parameter estimations w/ MIMO

5. Ensure precise timing and synchronization

and calibration to ensure accurate, repeatable

results

Addressing Technical Challenges


Keysight Test Solutions for 5G Research

Keysight 5G

Channel Sounding 34

Up to 16 channels

Up to 40 channels

Up to 104

channels

Wideband

RF/µW/mmWave Sub-6 GHz MIMO Channel Sounding

mmWave, BW, MIMO Massive MIMO

Receiver

Signal Generation & Analysis Phase Coherent Signal

Generation & Analysis

SystemVue Simulation

Software with 5G Library

Signal Studio Software

with Custom 5G

89600 VSA Software with

Custom OFDM/Demod

Transmitter Receiver

Page Page Thank You

– www.keysight.com/find/5G

– www.keysight.com/find/solution-5GSounding

– www.keysight.com/find/solution-5Gtestbed

Find more recourse like application notes, videos,

brochure, configurations

Keysight 5G

Channel Sounding

Keysight Solutions Unrivaled performance. Half the

time to insight.

35

http://www.keysight.com/find/5G

http://www.keysight.com/find/solution-5GSounding



http://www.keysight.com/find/solution-5Gtestbed




3 Setting options before the post processing of measurement

parameter – CIR/AoA/AoD/Doppler frequency/Pathdelay/Pathloss


Keysight 5G

Channel Sounding 36


Completing the Solution

– Software development services based

on the SystemVue platform to create

custom sounding signals and channel

parameter extractions

– Productivity services to complete the

project delivered by Keysight application

experts. Can provide addition

configuration, integration, consulting.

Find out more:

http://literature.cdn.keysight.com/litweb/pdf

/5989-0099EN.pdf?id=393341

– Extended support and training

Keysight 5G

Channel Sounding

Keysight Professional Services

37

http://literature.cdn.keysight.com/litweb/pdf/5989-0099EN.pdf?id=393341





mmwave mimo channel sounding for 5g — technical … with parameters such as path loss, delay,...

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