millimeter wave as the future of 5g

© Robert W. Heath Jr. (2015)

Millimeter wave as the future of 5G

Robert W. Heath Jr., PhD, PE Cullen Trust Endowed Professor Wireless Networking and Communications Group Department of Electrical and Computer Engineering The University of Texas at Austin

www.profheath.org


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Heath Group in the WNCG @ UT Austin 12 PhD students

mmWave precoding !

mmWave for tactical ad!hoc networks!

mmWave communication and radar for car-to-car!

mmWave licensed shared access for 5G !

mmWave for infrastructure-to-car!

mmWave wearables!

next generation !mmWave LAN !

mmWave 5G performance !


Why millimeter wave for 5G?

u  Huge amount of spectrum possibly available in mmWave bands u  Technology advances make mmWave possible for cheap consumer devices u  mmWave research is as old as wireless, e.g. Bose 1895 and Lebedew 1895

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300 MHz 3 GHz

30 GHz 300 GHz

cellular WiFi

note: log scale so even smaller over here

UHF (ultra high frequency) spectrum !


MmWave is coming for consumers

u  Standards developed @ unlicensed 60 GHz band ª WirelessHD: Targeting HD video streaming ª  IEEE 802.11ad: Targeting Gbps WLAN

u  Compliant products already available ª Dell Alienware laptops, Epson projectors, etc. ª  11ad Chipset available from Wilocity, Tensorcom, Nitero

u  Only single stream MIMO beamforming ª Next generation will likely support multi-stream (>20 Gbps)*

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Standard Bandwidth Rates Approval Date

WirelessHD 2.16 GHz 3.807 Gbps Jan. 2008

IEEE 802.11ad 2.16 GHz 6.76 Gbps Dec. 2012

Wilocity’s chipset***

Tensorcom’s chipset*** * http://www.ieee802.org/11/Reports/ng60_update.htm ** http://www.wirelesshd.org/consumers/product-listing/ *** http://www.dailytech.com/

Epson projector**

Dell Laptop**


Spectrum considerations u  There is no specific allocation for 5G cellular at millimeter wave yet u  Some candidate bands and their bandwidth (many shared with fixed and

mobile satellite, and federal / non-federal users)

u  FCC released a notice of inquiry to start the conversation about mmWave ª  NOI posses many questions that are being addressed by research at UT

u  Not obvious that exclusive licensing will happen in mmWave ª  Shared licensed access may be attractive due to reduced co-channel interference ª  Cognitive radio techniques may allow co-existence with satellite or radar

5 See UT’s response to comments here http://apps.fcc.gov/ecfs/comment/view?id=60001017585

28 GHz (LMDS) 1.3 GHz

39 GHz 1.4 GHz

37 / 42 GHz 2.1 GHz

71-‐76 GHz 81-‐86 GHz (E-‐Band) 10 GHz


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How does mmWave enable ultrafast broadband?

#1 spectrum

more spectrum (10x or more) larger channels (5-100x)

#2 large arrays & narrow beams

reduced interference (better SINR)

spectrum reuse (multiple users share same channel)


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Role of MIMO for mmWave

sub-6GHz aperture

mmWave aperture

TX RX

isotropic radiator

Beamforming for antenna gain

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… to 300 GHz

1.3 GHz 2.1 GHz

28 GHz 37 / 42 GHz

10 GHz

E-Band

7 GHz (unlic)

60GHz

millimeter wave band

Shu Sun, T. Rappapport, R. W. Heath, Jr., A. Nix, and S. Rangan, `` MIMO for Millimeter Wave Wireless Communications: Beamforming, Spatial Multiplexing, or Both?,'' IEEE Communications Magazine, December 2014.

just beamforming spatial multiplexing & beamforming

Spatial multiplexing for spectral efficiency

multiple data streams

several GHz of spectrum is promising but found in

many separate bands


Observations about antenna arrays

u  Large number of antennas used at the base station and mobile station ª  Antennas will be small -> no form factor challenges at the base station

u  Directionality of the patterns changes many aspects of system design ª  Physical layer signal processing ª Mobility management (e.g. initial access and handoff) ª  Interference management

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User equipment Base station

64 to 256 elements

4 to 32 elements


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Blockages will become more severe

Base station

Handset

Blocked by users’ body

X

User

self-body blocking

X

blockage due to people

hand blocking

blockage due to buildings

line-of-sight non-line-of-sight

many forms of blockage have yet to be modeled and analyzed


Observations about blockage u  Building blockage

ª  High density of infrastructure required to cover areas around buildings

u  Body blockage and self-body blockage ª Need rapid switching between line-of-

sight and non-line-of-sight paths ª Macro diversity where users associate

with multiple base stations

u  Hand blockage ª  Array diversity on the handset

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BS

User

LOS path

Reflected path

Buildings

Serving BS Blocked BS

X

Coordinating BS


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Analytical model for mmWave cellular systems

T. Bai, R. Vaze, and R. W. Heath, Jr., ``Analysis of Blockage Effects in Urban Cellular Networks”, IEEE Transactions on Wireless Communications, 2014. T. Bai and R. W. Heath Jr., “Coverage and rate analysis for millimeter wave cellular networks”, IEEE Transactions on Wireless Communications, 2015 Tianyang Bai, Ahmed Alkhateeb, and R. W. Heath, Jr., `` Coverage and Capacity of Millimeter Wave Cellular Networks,'' IEEE Communications Magazine, September 2014.

Interfering Transmitters

Associated Transmitter

Buildings

Typical Receiver

NLOS Path

LOS path

Simplified model for directional beamforming !

Main lobe beamwidth

Main lobe array gain Back lobe gain

Random building model for LOS/NLOS links !

Random building model

LOS: K=0 non-LOS

K>0

exponent proportional to building density

Exponentially decaying LOS prob.


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Performance calculations scenario 5% rate

（Mbps） avg rate (Mbps)

UHF with 1TX 1RX 1.26 67.53

UHF with 4TX 4RX 13.22 148.95

mmWave with low density and building blockages 2.95 2579.62

mmWave with high density and building blockages 2427.2 3716.41

mmWave with high density and building / body blockages 2106.53 3682.32

UHF & mmWave with high density and building blockages 2434.1 3733.3

UHF (2 GHz)parameters: Carrier frequency: 2 GHz BW: 50 MHz ISD: 500 m TX power: 46 dBm MIMO with ZF receiver

MmWave parameters: Carrier frequency: 28 GHz BW: 500 MHz ISD: 100 m (Dense) 200m (Sparse) TX power: 30 dBm BS beamwidth: 10 degree BS beamforming gain: 20 dB MS beamwidth: 90 degree MS beamforming gain: 6 dB Body blocking loss: 30 dB Body blocking prob.: 1/6 Building statistics: LOS range: 200 m (Austin downtown) Rate computation: 5 dB gap from Shannon SINR clipped by 30 dB

Maximum rate from two bands all outdoor users!


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Conclusion

Buildings Femtocell

Microwave Macro BS

mmWave D2D

Indoor user

mmWave BS

Control signals

Multiple-BS access for fewer handovers and high rate

Wireless backhaul

Data center

LOS links

Non-line-of-sight (NLOS) link

[1] Tianyang Bai, Ahmed Alkhateeb, and R. W. Heath, Jr., `` Coverage and Capacity of Millimeter Wave Cellular Networks,'' IEEE Communications Magazine, September 2014. [2] Ahmed Alkhateeb, Jianhua Mo, N. González Prelcic and R. W. Heath, Jr., `` MIMO Precoding and Combining Solutions for Millimeter Wave Systems,'' IEEE Communications Magazine, December 2014. [3] Shu Sun, T. Rappapport, R. W. Heath, Jr., A. Nix, and S. Rangan, `` MIMO for Millimeter Wave Wireless Communications: Beamforming, Spatial Multiplexing, or Both?,'' IEEE Communications Magazine, December 2014. [4] T. S. Rappaport, R.W. Heath, Jr. , J. N. Murdock, R. C. Daniels, Millimeter Wave Wireless Communications, Pearson, 2014

https://www.youtube.com/watch?v=BQ45FuGpFQ0

mmWave will impact every aspect of cellular communication

millimeter wave as the future of 5g

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