5G Enabling Technologies

An Unified Adaptive Software Defined Air Interface

Dr. Peiying Zhu

Huawei Fellow

Sept 3rd, 2014, PIMRC

5G World

Everything on Mobile Everything Connected Everything Virtualized

400MHz

100GHz

10GHz

D2D

VerticalsMBB

Open OTT

SDN-RAN

IoT

5G（Beyond Smartphone）

Capacity 1000X

（Capacity/km2)

Speed 100X

（10Gbps)

Latency Less than

1ms

Links 100x

Energy 1000X

Reduce

Auto-drive Medicare

Robots Meters Sensors

Transform the Industry Verticals

5G（Beyond Internet Access and APPs）

Latency （ms）

Links（Per/km2）

Speed（kbps/km2）

Unprecedented Performance Challenge

No-Cell Virtual RAN

Software Defined &Simplicity

Service Aware and Monetize

Stretched in 3 Dimensions

Speed

Links

Response

Spectrum Efficiency

All Spectrum Access

Networks Re-Architect Challenge

Cellu

lar

Ban

ds

Vis

ible

Lig

ht unlicensed unlicensed

10 20 30 40 50 60 70 80 90 5 GHz

50m 50-100m 0.5-2km 40GHz 2.5GHz 0.5GHz

Primary

Band

Complementary

Band

Macro 1Gbps~4Gbps

Micro 3Gbps~10Gbps

Local 10Gbps~100Gbps

Single & Unified Air-Interface

for All Spectrum Access

Foundational Technologies

Massive MIMO

5G mmWave

Full/ Flexible Duplex

5G RAN&Core

5G UE

5G Vertical

Product Development Phase

Standardization Phase

5G Air

Interface

(2014

-2018)

Research Phase

Air Interface Characteristics

Virtualized

& Software

Defined

RAN

Primitives

Variable

sub-Carrier

Tailored to

Applications

Ultra-narrow Bands for Internet of Things Applications

Ultra-wide-Bands for Virtual Reality Applications

Ultra-low Latency for Vertical Applications Capacity

X1000

Latency

X1/10

Links

X100

Coverage

30dB

Reliability

x1000

Mobility

500km/h Spectrum

Efficiency

X30

Sparse Code

Multiple Access

(SCMA)

F-OFDM

Spectral

Localization

Orthogonal-

free &

Synchronous

free

SCMA (Sparse Code Multiple Access)

A new frequency domain non-orthogonal

waveform Input bits are directly mapped to codewords and spread over multiple sub-carriers

Codewords can be assigned to same UE (SU-SCMA) or different UEs (MU-SCMA)

Non-orthogonal multiplexing of code layers

Over-Dimension to increase overall rate and

connectivity

Sparsity to limit Rx complexity for detection

Multi-dimensional codewords with shaping gain

Spreading for robust link-adaptation, coverage

UE1

UE2

UE3

UE4

UE5

UE6

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

FEC Encoder 1

FEC Encoder 2

FEC Encoder 3

FEC Encoder 4

FEC Encoder 5

FEC Encoder 6

b11b12…

b21b22…

b31b32…

b41b42…

b51b52…

b61b62…

f

SCMA block 1 SCMA block 2

SCMA: N (6) symbols mapped to K (4) sub-carriers

(N > K, overloading)

LTE: K (4) symbols mapped to K (4) sub-carriers

SCMA Code Book

UE1 UE2 UE3 UE4 UE5 UE6

(1,0) (0,0) (1,1) (0,1) (b1,b2) (1,0) (1,1)

16-point orthogonal lattice

in 4 real dimensions

Unitary

lattice

rotation

Rotated 16-point lattice

in 4 real dimensions

Mother

constellation

Projections on first and

second complex dimensions

QPSK 1 QPSK 2

0000

0000

SCMA codebook based on Multi-dimensional Lattice Constellation to exploit shaping gain and coding gain

Each UE/layer stores a unique codebook

Binary input data is mapped to a codeword of the corresponding codebook

Low PAPR and low projection codebooks possible

Scalable SCMA

with Adaptive System Parameters

System requirements

Network/UE

capabilities

SCMA Parameters

SCMA

Configuration SCMA Mode

Link-budget

Coverage

Connectivity

Throughput

Multiplexing gain

Processing

capabilities

……

SCMA

OFDMA (fall back mode)

NOMA (fall back mode)

……

Number of codewords of an SCMA codebook: M

Spreading factor: K

Max number of layers (or codebooks/signatures) : J

Number of nonzero elements of each codeword: N

……

Flexible and scalable SCMA based access scheme which can compromise among spectral

efficiency, coverage, detection complexity, connectivity, and link budget to adapt to different

application scenarios

Issues for OFDM Waveform

OFDM

FBMC

Spectrum not localized, need guard band

Frequency

Time

OFDM

sub-carrier

spacing=15 kHz

Not flexible to change sub-carrier spacing in Frequency

time

Ch. 1

Ch. 2

Ch. 3

freq.

OFDM

UE #1

OFDM

UE #2

OFDM

UE #3

time

FFTdata of all

UEs

Synchronous Tx, large overhead for time alignment

frame

10 ms

TTI-1 TTI-2 TTI-

10

1 ms

Slot-

1

Slot-

2

0.5 ms

Symbol-1 Symbol-2 Symbol-7

Cyclic prefix (4.7 s)

66.7 s

Cyclic prefix (5.2

s)

Normal CP

frame

10 ms

TTI-1 TTI-2 TTI-

10

1 ms

Slot-

1

Slot-

2

0.5 ms

Symbol-1 Symbol-2 Symbol-7

Cyclic prefix (16.7

s)

66.7 s

Cyclic prefix (16.2

s)

Extended CP

Fixed symbol duration, not flexible to change CP

Spectrum Filtered OFDM (f-OFDM)

1. Sub-band digital filter

is applied to shape the

spectrum of subband

OFDM signal.

2. Orthogonal

subcarriers within

each subband

3. Allow co-existence of

waveforms with

different OFDM

Primitives

Frequency

Time

OFDM

sub-carrier

spacing=15 kHz

OFDM

sub-carrier spacing=3

kHz

OFDM

sub-carrier

spacing=30 kHz

Spectrum Filtered OFDM (f-OFDM)

1. Sub-band digital filter

is applied to shape the

spectrum of subband

OFDM signal.

2. Orthogonal

subcarriers within

each subband

3. Allow different cyclic

prefix for each specific

sub-band

Frequency

Time

F-OFDM Supports Asynchronous

OFDMA

time

Ch. 1

Ch. 2

Ch. 3

Freq.

Filtered

OFDM

UE #1

Filter #1Freq. Short FFT

processing

for UE #1

Short FFT

processing

for UE #2

Short FFT

processing

for UE #3

Filtered

OFDM

UE #2

Filtered

OFDM

UE #3

Filter #2

Filter #3

1. Support

asynchronous

OFDMA

transmission

2. Non timing

advance

signal needed

Spectral Filtered OFDMA

Characteristics

1. Good out-of-band

leakage rejection

2. Similar spectrum

localization

performance

compared to

FBMC

3. Maintain all the

benefits of OFDM

4. Easy for m-MIMO

-8 -6 -4 -2 0 2 4 6 8-180

-160

-140

-120

-100

-80

-60

-40

-20

0PSD Spectrum

Frequency(MHz)

PS

D

OFDM

UFMC

Filtered-OFDM

FBMC

2.2 2.25 2.3 2.35 2.4 2.45 2.5 2.55 2.6 2.65 2.7

-140

-120

-100

-80

-60

-40

-20

PSD Spectrum

Frequency(MHz)

PS

D

Flexible Time-frequency Lattice

1. Co-existence of

different time-

frequency

granularities

2. Waveform

optimized for

different

transmission

condition and

applications

3. Regional

broadcasting, high

speed train, fixed

devices,……

4. Subband

spectrum filter to

control inter-block

interference

Spectrum filter

f

t

OFDM symbol

duration Guard time

Sub-carrier spacing

f

t

OFDM symbol

duration

Guard time

Sub-carrier spacing

Frequency

Time

An Unified Adaptive Software Defined Air

Interface to Meet Diverse Services Demand

Unified air interface to support

different waveform / multiple access schemes / flexible TTI

UE1

UE2

UE3

UE4

UE5

UE6

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

SCMA MODULATION

CODEBOOK MAPPING

FECEncoder 1

FECEncoder 2

FECEncoder 3

FECEncoder 4

FECEncoder 5

FECEncoder 6

b11b12…

b21b22…

b31b32…

b41b42…

b51b52…

b61b62…

f

SCMA block 1

TIME

FR

EQ

UE

NC

Y

IoT

Networks

Vehicular

Networks

HDV

Networks

Smart Life

Networks

HD Video

Surveillance

Meter &

Sensor

High Speed

Train

Automatic

Driving

Wireless

Cloud Office

Voice

Gaming

SCMA Prototype and Field Trial

5G Timeline