Beyond-5G Networks with Massive MIMO · progressive or dynamic networks. Small Cell Operation Non-Cellular Approach: Cell-Free Single-antenna sites Antenna cluster • Clusters of

1 DOCOMO Innovations, Inc., Copyright 2017, All rights reserved

Ozgun Bursalioglu [email protected]

Beyond-5G Networks with Massive MIMO


Higher data rate Reduced Latency

Massive device

connectivity

Energy saving &

cost reduction

Higher system

capacity

Massive

MIMO

B5G Requirements


Higher data rate Reduced Latency

Massive device

connectivity

Energy saving &

cost reduction

• IoT devices, cars, etc.

Higher system

capacity

Massive

MIMO

B5G Requirements

• AR/VR applications,

remote control etc.


What is Massive MIMO?

• A very large antenna array at BS.

• An order of magnitude more antenna elements in conventional systems.

• A large number of user are served simultaneously.

• Combination of Massive MIMO and Macro-Assisted Small Cell can provide coverage even with high frequency bands.

Many more

antennas at BS Many users

Macro-Cell

Small-Cell


Macro Base Station

Image source : https://www.flickr.com/photos/pouchin/7831847758

serving a few users per each resource

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multiplexing more users per

each resource

Macro Base Station

6


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? ?

?

?

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more and more customers /

services

Macro Base Station

7


Edge users Edge users

Adding more BS sites: Many small cells Careful planning is needed to provide coverage & control interference

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Moving to Higher Frequency Bands - Massive MIMO sites at mmWave have much smaller footprint, many new

sites can be added to the network.

- Intermittent connectivity, increased blockage, and shorter coherence time

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Moving to Higher Frequency Bands - Massive MIMO sites at mmWave have much smaller footprint, many new

sites can be added to the network.

- Intermittent connectivity, increased blockage, and shorter coherence time

- Careful planning of networks is not practical

New “challenges” for dense future networks at higher bands:

• Progressive site densification / user densification, flexible planning

• Interference Management, Load balancing, UE-BS Association

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Moving to Higher Frequency Bands With various IoT devices comes dramatically increased user densification




• Random Access




• Random Access

New “opportunities” for dense future networks at higher bands:



• Random Access 11


Denser Networks: Higher site density

• Very challenging propagation at higher bands (e.g., mmWave),

intermittent connectivity

• For substantial rates/unit area, we need high density of mmWave sites

• Advantageous to have several sites nearby a UE

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Anticipated Challenges in 5G and Beyond

• It is expected that the network will be progressively densified.

• Careful planning and maintenance of very dense HetNet

deployments (with multi-tier BSs operating over a broad range

of bands) is neither cost-efficient nor practical.

• We need to re-think deployments and consider new

architectures - Allowing fast adaptation for each user individually

- Allowing user densification (simultaneously serving many users/unit area)


Different styles of operations

• Users are associated to a single BS

• Careful planning required, not suitable for

progressive or dynamic networks.

Small Cell Operation Non-Cellular Approach: Cell-Free Antenna cluster Single-antenna sites

• Clusters of BSs acting as a giant cell

• High operational complexity

• Still have edge users / performance


Our Proposal

• Immediate, on-the-fly, distributed cluster forming w/o any cooperation between BSs.

• This is possible with collision detection and user identification capabilities at BS

enabled by large antenna arrays and special pilot code designs.

Massive

MIMO RRH

Plug & Play User Centric Cell :

Spotlight

Cluster of BSs serving a user is specific

to that user User Centric approach


Spotlight

• Throughput densification (serving many users & large rates/unit area)

• Non orthogonal pilot designs and fast user detection at each RRH (or RRH sector)

• Scalable, robust, low-planning flexible deployment, lower maintenance cost

• Attractive CAPEX and OPEX

BBU

BBU BBU

• We are exploring a new type of architecture based on:

- TDD and UL signals for training and association

- Large antenna arrays at each RRH

- Using BBU pools that are connected to overlapping sets of RRHs

• The architecture is inherently user-centric and scalable.

• Seamless low-overhead hand-offs.


Performance gains (Sample Result)

Spotlight

Current Technology

Performance

improvement

Z. Li, N. Rupasinghe, O. Y. Bursalioglu, C. Wang, H. Papadopoulos and G. Caire, “Directional Training and Fast

Sector-based Processing Schemes for mmWave Channels,” ICC, 2017.

Strictly improved rates

for all users


Ozgun Y. Bursalioglu

[email protected]

Documents

Beyond-5G Networks with Massive MIMO · progressive or dynamic networks. Small Cell Operation Non-Cellular Approach: Cell-Free Single-antenna sites Antenna cluster • Clusters of