© 2016 NTT DOCOMO, INC. All Rights Reserved.

3.5GHz Development in DOCOMO

Hiroyuki Atarashi

Radio Access Network Development Department NTT DOCOMO, INC.

© 2008 NTT DOCOMO, INC. All rights reserved. © 2016 NTT DOCOMO, INC. All Rights Reserved.

Introduction (1)

• The 3.5GHz band was licensed to three Japanese mobile operators in December 2014

• Several technical requirements were specified: – LTE-Advanced (TDD) – Requirements for base station deployment, such as more than 50% of

the population coverage – Application of technologies for efficient utilization of spectrum, such

as carrier aggregation, adaptive modulation, etc.

NTT DOCOMO KDDI Softbank

Microwave links for broadcasters

Satellite systems

3400 3456 3480 3520 3560 3600

To be licensed until November, 2022 (MHz)

Assigned spectrum (40MHz each x 3 operators)

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Introduction (2)

• NTT DOCOMO launched the 3.5GHz commercial service in June 2016

• This presentation provides overview of: – DOCOMO’s 3.5GHz technology development – DOCOMO’s 3.5GHz commercial service

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DOCOMO’s 3.5GHz technology development

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“Advanced C-RAN architecture” concept

• DOCOMO’s proposed RAN architecture concept for LTE-Advanced – Integration of “Carrier aggregation (CA)” and

“Small cells” using “C-RAN architecture”

BBU

BBU: Based-Band Unit, RH: Radio Head

Optical fibers

Small cells (3.5GHz TDD)

CA

RH

CA

CA

RH

CA

Macro cell (FDD)

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RH

RH

RH

RH

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Advantages of “Advanced C-RAN architecture” • Suitable for small cells deployment providing:

– High data rate and high-capacity network – Good mobility performance

Without Advanced C-RAN architecture

Handover Handover Handover Handover

Data rate

With Advanced C-RAN architecture

Data rate

CA CA

Always connected to macro cell & High data rate in small cells

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Developed RAN equipment for 3.5GHz • Various deployment scenarios are supported

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GPS

RH Antennas

RH Antennas

Antenna FHM RH

For indoor

FHM

For small cells

BBU

For macro cells

NW synchronization

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Base Band Unit (BBU) • Up to 48 cells can be accommodate to realize

“Advanced C-RAN architecture” • This BBU can accommodate 3.5GHz-cells as well as

existing FDD frequency bands’ cells • Combination of different vendors’ BBU and RH is

possible (i.e., multi-vender solution)

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Radio Head (RH) for 3.5GHz • Two types of RH for different scenarios

– RH for 3.5GHz small cell & indoor – RH for 3.5GHz macro cell in suburban/rural scenarios

For small cells/indoor For macro cells

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• 0.48W/20MHz/branch • Less than 4L

• 19W/20MHz/branch • Less than 9L

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Antennas for 3.5GHz

• Different types of antennas have been developed for different deployment scenarios

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For small cells For macro cells For indoor

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FrontHaul Multiplexer (FHM)

• A FHM distributes & combines a maximum of 16 RF signals on the fronthaul

• It can provide a economically efficient solution to serve different areas as a single cell

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BBU

FHM

FHM FHM

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Further details

• Further details can be found in “Special Articles on Introducing the 3.5-GHz Band” in “NTT DOCOMO Technical Journal”

– NTT DOCOMO's Efforts Concerning Technical Developments for Introducing TD-LTE in 3.5-GHz Frequency Band

– Base-station Equipment with the Aim of Introducing 3.5-GHz band TD-LTE

– Base Station Antennas for 3.5-GHz Band – High-precision Clock-time-synchronization Network Equipment for

Introduction of 3.5-GHz band TD-LTE – Router-type Mobile Terminal for TD-LTE in 3.5-GHz Band

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DOCOMO’s 3.5GHz commercial service

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Japan’s first 3.5GHz commercial service

• 370Mbps service using the 3.5GHz band – Launched in June 2016 in 35 cities across Japan – Currently, expanded to 50 cities across Japan*

* Other than Tokyo, Nagoya and Osaka, 332.5Mbps service using 3.5GHz is available in 32 cities across Japan

Maximum 110Mbps

Maximum 110Mbps

3.5GHz

3.5GHz

Maximum 150Mbps 1.7GHz

Aggregation Maximum 370Mbps

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Planned further enhancement

• Service will be enhanced to

682Mbps using 4x4 MIMO & 256QAM

2015 2020

5G FY 2014

2016

PREMIUM 4G

225Mbps 300Mbps 375Mbps

370Mbps

3CC using FDD

bands

3.5GHz TDD+FDD

682Mbps

3.5GHz TDD+FDD 4x4 MIMO 256QAM

~1Gbps

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Maximum

682Mbps

Maximum 241Mbps

Maximum 241Mbps

3.5GHz

3.5GHz

Maximum 200Mbps 1.7GHz

Aggregation

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Thank you for your attention

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