what is in for D2D in 5G wireless

support of underlay low-rate M2M links

Petar Popovski [email protected]

Aalborg University, Denmark

will

not only

be

“4G, but faster”

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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5G research @ EU

FP7 METIS M obile and wireless communications E nablers for the T wenty- twenty (2020) I nformation S ociety Budget:

27 M €

.

Objective: 5G

by 2020 system concept that meets the requirements of the 2020 connected information society and extend today’s wireless communication systems to support new usage scenarios . Such a system has to be more

efficient, versatile

, and

scalable

compared to today’s systems.

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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METIS system concept

immense task, split into 5 Horizontal Topics  direct Device-to-Device communication (D2D) how to efficiently enable and for what to use D2D  Massive Machine Communication (MMC) how to support a massive number of low-cost, low-energy devices WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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METIS system concept

 Moving Networks (MN) extend the current wireless infrastructure to moving/nomadic nodes and create new services  Ultra-Dense Networks (UDN) provide and sustain high rates to a large number of users in close proximity  Ultra-Reliable Communication (URC) how to guarantee certain connectivity or latency 99.999+% of the time WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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data rate Gbps Mbps kbps bps 1

a biased personal summary of 5G R1 R2 ≥99% R5

R1: today’s systems R2: high-speed versions of today’s systems R3: massive access for sensors and machines R4: ultra-reliable connectivity R5: physically impossible

R4 ≥99.999%

10 100

R3 ≥90-99%

1000 1000 0 # devices WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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direct D2D

refers to local D2D communication controlled by the core network   it can potentially improve  reliability   latency throughput per area spectral efficiency machine-type access

new services

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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  extended coverage  multi-hopping network coding cooperative diversity ad hoc networking in emergency fallback solution

D2D for reliability

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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 how to do this reliably in 2020+?

D2D for latency

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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D2D for latency

network-controlled D2D has an advantage over pure Bluetooth-like D2D    facilitates leader election in neighbor discovery and link rendezvous interference control (licensed spectrum) diversified connection WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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offloading and local content sharing close connection to

caching

D2D for throughput

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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D2D for spectral efficiency

the D2D setting looks like a  

cognitive radio

with

consensual primary

spectral efficiency in the previous example another example is to use the features of the multiple access channel

D3

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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D2D support of machine-type access

trunking effect and coordination

decrease the random access pressure on the Base Station WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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D2D support of machine-type access

low power uplink

sensor attached to a phone underlay operation in the same spectrum WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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D2D in the 5G diagram

data rate Gbps Mbps

R2 offloading, prosumers R1

kbps bps 1

R4

10

reliability, latency

100

R3

1000

R5 machine type access

1000 0 # devices WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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D2D for underlay machine-type access

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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scenario of machine-type D2D Normal D2D B Low Power Consumption

U1 M1 U2

Access Load Relief Area Base Station Cellular Device Cellular MTD Device-to-Infrastructure Device-to-Device Machine-Type Device-to-Device

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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B

U M

model of underlay operation Base Station Cellular D evice Cellular M T D D evice-to-I nfrastructure M achine-T ype D evice-to D evice A ggregate I nterference

I~ WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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B U M problem definition

assume that B knows the channel B-U but not the channel M-U U can decode both signals from B and M how should B select the downlink rate R B , so that the downlink is not in outage?

transmission WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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multiple access channel at U B

C

R B R M0 is fixed

C

( g

B

+ g

M

)

U

C

æ è g

B

1 + g

M

ö ø

M

C

è g

M

1 + g

B

ø

C

low R M0 candidate for interference cancelation R M WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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three MAC regimes with joint decoding (JD)

maximal decodable R B R B R B R B R M0 R M0 not decodable R M R M0 joint decoding of R B and R M0 R M WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

R M0 SIC: R M0 first removed R M 21 / 30

max R B as a function of the strength of the link M-U

rates

R

B and

R

M0 represented

equivalently

through SNRs G B and G M outage no outage G

B

= g

B

1 + G

M

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

possible to select R B and avoid outage independently of the fading statistics for M-U 22 / 30

outage for the link M-U

below this value g

B

G

M

1 outage affected only by the statistics of the M-U link G

M

outage g

B

G

B

1 no outage g

M

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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maximal zero-outage rate

R B

= log 2 æ è 1 + g

B

1 + G

M

ø

C

è g

B

1 + G

M

ø

R

M0 increases as the rate

(

G M

) decreases

WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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B U M a simple single-user decoder

C

R B R M0 is fixed

C

( g

B

+ g

M

)

C

è g

B

1 + g

M

ø

C

è g

M

1 + g

B

ø

C

R M WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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maximal R B with single-user decoding

G

B

outage no outage G

B

= g

B

1 + G

M

(1 + g

B

) maximal zero-outage R B is lowered is a penalty , there due to single-user decoding WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

G

M

(1 + g

B

) g

B

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evaluation scenario B

U M  U is the reference point

Base Station

  a unit-radius circle

Cellular M T D

centered at U

D evice-to-I nfrastructure M achine-T ype D evice-to-

B and NM-1 MTDs I~ within the disk of radius R σ 2 P M = −97.5[dBm] =−10[dBm] WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

α=4 R=200[m] P B =30[dBm] 27 / 30

numerical results

1 0.8

0.6

0.4

0.2

0 0.1

6 4 2 0 0.1

0.2

0.2

0.3

0.4

0.3

0.4

0.5

R M 0.6

0.5

R M 0.6

0.7

0.8

JD Analytical JD Simulation SD Simulation 0.9

1 0.7

0.8

0.9

1 WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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regime of high interference

3 2 1 0 10 1 6 5 4 10 2 WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

N M 10 3 Absent M−U JD R M = 0.01

SD R M = 0.01

R M = 0.1

R M = 1 R M = 10 29 / 30 10 4

summary

D2D will play multiple roles in 5G and improve  reliability, latency, throughput per area, spectral efficiency, machine-type access   we have considered underlay D2D for low-power low-rate machine access outage-free transmission even in presence of underlay keys: low rate and successive interference cancellation next steps  evaluate the concept with actual modulation/coding  D2D for trunking in M2M access WDPC @ WCNC @ Istanbul, Turkey, April 6, 2014.

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