1 © 2019 The MathWorks, Inc.

Hybrid Beamforming for 5G

System Level Modeling

Gerald Albertini

November 08th 2019

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System Level Modeling / team collaboration

Baseband Digital

Front End DAC PA

LNA ADC Baseband Digital

Front End

Digital PHY RF Front End

Antenna

TRANSMITTER

RECEIVER

Channel

RF Design DSP Algorithms

Software

Development System

Architecture

Digital

Hardware

Mixed-Signal

Hardware

Antenna

Design

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BB Modeling : Support Latest Standards

5G Toolbox: A new product for simulating, analyzing,

and testing the physical layer of 5G communication

systems

IEEE 802.11ax and 802.11ad are new Wi-Fi standards

intended for high data rate communications

NB-IoT and LTE-M are machine-to-machine (M2M)

applications for the Internet-of-Things (IoT)

D2D and C-V2X are LTE application for device-to-device

and cellular vehicular communications

Simulate, analyze and test 5G radio links. Generate

IEEE 802.11ax/ad and LTE NB-IoT, LTE-M, D2D, and C-

V2X compliant waveforms

LTE Toolbox™

+

+

5G Toolbox™

+ WLAN Toolbox™

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Easily and graphically configure,

generate, visualize and export wireless

waveforms. Connect and transmit

waveforms on RF instruments

Supported waveforms

– WLAN: (IEEE 802.11a/b/g/j/p/n/ac/ah/ad/ax)

– LTE: (Uplink & Downlink RMC and E-TM)

– Custom-modulations: (QAM / PSK / OFDM)

RF instrument connectivity (e.g., Agilent,

Rohde & Schwarz)

– Automatically discover available instruments

– Transmit/stop infinitely looped waveforms

Ease of use : Wireless Waveform Generator App

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Antenna Array Modeling

Design subarrays

Synthesize arrays Model mutual coupling Model imperfections

Design/import antenna

patterns

Design an array

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Design the radiating element (antennaDesigner)

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Design the Array (sensorArrayAanlyzer)

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Building an Array Using Subarrays

Replicate to build array

Assess resulting pattern

Design subarray with desired fidelity

or

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Channel Models

• LOS propagation channel

• Multiple-ray propagation channel

• 5G channel model

• Scattering MIMO channel

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Let’s look into a few examples…

www.mathworks.com/help/phased/examples.html

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1>> All Digital : MIMO-OFDM Precoding Example

Beamforming where each transmit/receive element is controlled with amplitude and

phase

Baseband

precoding

DAC RF

… NT

…

DAC RF

Baseband

combining

ADC RF

… NR

…

ADC RF

https://www.mathworks.com/help/comm/examples/mimo-ofdm-precoding-with-phased-arrays.html

Single-user MIMO-OFDM system

Up to 16 data streams

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Transmit and Receive Beam Steering

Transmit

Receive

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2>> Introduction to Hybrid Beamforming

Beamforming done in two stages:

– RF Beamforming

– Digital Beamforming

Baseband

R

F

R

F

R

F

R

F

H Baseband

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Constraints in Hybrid Beamforming

Partitioning is an optimization problem with constraints

Magnitude and phase flexibility (vs. analog only phase shifter)

Power limits

Phase shifter finite resolution

Phase shifter bandwidth performance

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Pattern and Spectrum Efficiency Comparisons

Beampattern with hybrid weights (discrete hybrid beamforming)

Beampattern for optimal precoding weights (all digital)

Spectrum Efficiencies of Optimal Weights and Discrete Weights

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Hybrid Beamforming with Sparse Beamspace Precoding

Need only as many RF chains as number of Tx data streams (𝑁𝑆)

Number of transmit antennas >> 𝑁𝑆 (𝑁𝑅𝐹), with appropriate RF beamforming

Map each RF chain to each Tx

element

Map each RF chain to only a subset

of Tx elements (subarrays) Virtual sectors (MU case)

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Closed loop simulation - Simulink

System level modeling

Multidomain (baseband, RF modeling)

Closed look (feedback)

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Digital and Analog Precoding

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Modeling RF

Signal to RF gateway

Model reflections

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Summary

Antenna, RF design & signal processing development in single environment

Modelling can help to define architectures for hybrid beamforming

The hybrid beamforming algorithm well suits for limited feedback systems

The hybrid beamforming algorithm can approach the theoretical limits on spectral efficiency

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Q and A