“Real 5G” should be 4.9G

Kazuhiko Goukon
Senior Scientist, Technology OfficeSoftbank Corporation

Copyright © 2016 Softbank corp. all rights reserved.

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Everyone’s “5G” is Chitty-Chitty Race
>10Gbps /user(LOS)

mmWave(LOS)

1GHz
Band Width

Ultra Dense
Small Cell(No Interference)

Too much
Computation power

This cannot be acommercial product!

Copyright © 2016 Softbank corp. all rights reserved.

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“Real 5G” should be…
■ Low bit cost through mathematical computation strength relaxation● Linearly increasing cost along with computation power is horrible● Vendor should try to decrease computation power■ Wide coverage with improved UL link budget● Common channel sweeping should be realized● UL is mainly for SRS● Time domain SRS power concentration with 1/8 UL/DL ratio.
➢9dB UL power boost■ Broadcast channel beamforming● LTE has area limitation with broadcast channel link budget● 5G’s common channel should be Beamforming somehow■ User Centric Cell
■ SDMA■ Should fall back and compatible with 4G radio

These are almost the same as 4GCopyright © 2016 Softbank corp. all rights reserved.

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Key function of “Real 5G”■ User Centric Cell
● Dedicated Reference Signal tracks UE with beamforming
without handover in entire coverage

NoHandover■ SDMA (MU-MIMO)● Zero-Forcing based interference mitigation Massive MIMO orDistributed MIMO
● SDMA should use channel reciprocity of TDD with SRS from UE

Copyright © 2016 Softbank corp. all rights reserved.

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Our 5G strategy■Aligned with 5G trial in China initiated by CMRI
and the vendors● China case, 3.5GHz would be used
● Just changing frequency, nothing other■Target is● Station and NLOS
● Multi-User Massive MIMO (not single user)● User Centric Cell
● Massive MIMO would eventually achieve
10Gbps/cell capacity

Copyright © 2016 Softbank corp. all rights reserved.

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2.5GHz, 3.5GHz and 5G

2.5GHz30MHz

3.5GHz40MHz

5G200MHz

User Centric Function■Every TDD system should go to User Centric■5G is just wider band width

Copyright © 2016 Softbank corp. all rights reserved.

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SRS Switching (4G/5G) is necessary for Carrier Aggregation
BaseStationSRS

Downlink

Reciprocal SDMA iskey technology of5G!

TDD can use SRS for uplink channel estimationSecondary Carrier also needs SRS signal

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High Power UE (+9dB)■Usually LTE network is uplink limited, especially TDD
System■5G’s frequency allocation would be in higher band, thatmeans cell radius would be shrunk
Coverage of
23dBm UE

High Band 5G(e.g. 4.5GHz)

Coverage ofHigh Power UE

Band 41

Band 41
High Band 5G(e.g.4.5GHz)

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SoftBank Massive MIMO
RF ParameterFrequency : 2555-2575 MHz(Band 41)
Band width : 20 MHz

Transmit Power : 20WCell Parameter
DL-UL ratio : DL / UL= 3 / 1(Synchronized with commercialNW)

Surrounded by commercialnetwork

UE:Existing Rel-9 UECopyright © 2016 Softbank corp. all rights reserved.

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The difference is just bandwidth!

4G (20MHz BW) over 600 Mbps / site

5G (200MHz BW) over 6 Gbps / site
DLthroughput/ site716
M

In Theory
600M

In Real(bps)110M
Massive MIMO

60M

Commercial NW 20MHz 2 layer

Copyright © 2016 Softbank corp. all rights reserved.

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Massive MIMO at 3.5GHz■ We think Massive MIMO is suitable for 3.5GHz, too■ Our 3.5GHz is almost same configuration as 2.5GHz
It should notbe smaller?

Copyright © 2016 Softbank corp. all rights reserved.

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CPU Interconnect with GPGPU through CMN■ CPU with GPGPU (General-purpose computing on
Graphics Processing Units) through CPU interconnect
would be essential key for 5G low cost implementation
for future high speed BBU■ CPU array and GPGPU array can be inside in one
single chip with AMBA (Advanced Microcontroller Bus
Architecture) bus■ Already BBU is similar structure but future one would
definitely use CPU array + GPGPU array mixed through
OpenACC based C++ plus pragma with regular C++
based no stress computing.
■ AMBA (Advanced Microcontroller Bus Architecture) andCMN (Coherent Mesh Network) is proprietary
technology of ARM
Copyright © 2016 Softbank corp. all rights reserved.

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Copyright © 2016 Softbank corp. all rights reserved.

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