Hetergeneous Networks IMPROVE · PDF fileSmooth spectrum refarming. GSM WCDMA LTE. WCDMA LTE....

IMPROVE

DENSIFY

ADD

Hetergeneous Networks

HETNET

HetNet | Public | 2012-03-23 |

Why and what HetNet

is About End User Experience

Always onAlways on

CoverageCoverage

Speed andlow latencySpeed andlow latency

CapacityCapacityCoverage is taken for granted

But is bitrate dependent

Cell edge performance user experience

Data and voice volume capacity to serve all subscribers

Signaling Capacity everywhere


Tablets

Peakrates: 20- 40 Mbps

Expectation : 5/1 Mbps

Volume: 2 GB/month

Device impact Network Requirement

Dongles

Peakrates: 20-80 Mbps

Expectation: 10/2 Mbps

Volume: 1, 3, 5, 10 GB/month

Smartphones

Peakrates: 14-21 Mbps

Expectation : 2/0.5 Mbps

Volumes: 500 MB/month

DemandPeakrates: 100 Mbps

Expectation: 20/5 Mbps

Volume: 30 GB/month

Despite the growth in data volumes subscriber demands on bitrate may

be the big driver for network evolution!

TodayTomorrow

http://www.idg.se/2.1085/1.362265/verizon-hardsatsar-pa-lte?showGallery=true&img=8#selected




Network Challenges

Data Volume Growth

Cell Edge Performance~10kbps (voice) =>10Mbps defining coverage

Not easy to make cell split in dense urban areas…

Expansion of sites with more antennas may cause protests

Not possible to maintain regular cell grid in dense areas

Less people for operating larger networks

Limited investment budget

Site expansion plans are often stopped by restrictions on making changes to touristic or historical areas or by a rapidly changing environment with new buildings affecting cell plans.


Hetnet strategy

Required Capacity

Improve

AddDensify

Current C

apacity


Data rate

The Radio Network Toolbox

’Super-macro’

Micro, Pico, Relays

’Super-macro’

3

1

2 3 2

1. Improve: ”Super Macro” – advanced antennas, spectrum aggregation, advanced Rx

2. Densify: More Cells – Site densification, Small cells – main remote, relays, pico3. Add: Dedicated indoor/enterprise solutions – as part of mobile operator offering


Maximize the

added value

Low Macro SIRHigh Macro SIR

Small added value:- Low offload per user - Similar bit rates - Small coverage area

High added value:- High offload per user - Higher bit rates - Large coverage area


Adding Coordinated Layers

› Improved data throughput with reuse of frequencies› Reduced interference with coordinated layers

–

Inter-Cell Interference Coordination (ICIC) in LTE

› Capacity off-load of macro network


Why embedded cells?

Maximum spectral efficiency

High bandwidth everywhere

Simplified traffic management

F1 F1 F1

F2F2 F2

F1

F2

Example: 10 MHz all sites vs 5 MHz per layer

- 50% more capacity - 100% higher bit rates


Adding low power nodes

Source: Ericsson

Adding a large amount of small cells, can only partially overcome the loss in the macro layer

Loss in macro layer by splitting spectrum

Use

r Thr

ough

put [

Mbp

s]

Downlink 3 GB/month

Coverage Probability [%]

20MHz

10MHz

10MHz + 12 pico

Don’t split the spectrum!


Downlink/uplink Imbalance The HetNet

handover dilemma

› For heterogeneous network deployments the transmit power of Micro can be much smaller than for macro (Ppico << Pmacro )

› Uplink sensitivity is similar between Macro and Micro› The best uplink cell does not neccessarily correspond to the best downlink cell...

–

Downlink: maximum CPICH Ec/No (or CPICH RSCP), RSRP–

Uplink: minimum path loss

Optimal DL handover

Optimal UL handover

Macro cell Micro cell

Best downlink cell

Best uplink cell

Macro

Macro

Macro

MicroMicroMicro

10-15 dB!

Uncoordinated microcells will shrink in size


Important to Extend Pico Range

› Macro offload to increase total downlink capacity› Leverage on pico uplink link budget and performance› Soft Handover for fast closed-loop interference control

Optimal DL handoverOptimal UL handover

Macro cell Pico cellBest downlink cellBest uplink cell

MacroMacro

MacroPico

PicoPico

Serving cell change Extended pico range (e.g. by a Cell Individual Offset)


Interference and traffic management

Inter-RAT Multi-cell

coordination

Inte

rfere

nce

mitig

atio

n

Inte

r-fre

quen

cy

Intra-frequency mobility


Interference Suppression a key HetNet feature

Interference Suppression a key feature for HetNets with unpredictable sources of interference


Multi-Standard

simplified

Fewer nodes, mixed modeService continuityEffective traffic managementSmooth spectrum refarming

GSM WCDMA

LTE

WCDMA LTE

WCDMA LTE WiFi

Similar cell plans the key


Hetnet

coordination

CtrlSmall RBS

Enhanced Iub S1/X2

RRU

Main unit

RRU

RRU

Small RBS

Macro RBS

Internet

RRU

Leverage on proven macro functionalityTight coordination through controllerAdvanced radio coordination – when needed

Iub/S1/X2


UL coordinated multipoint

› Up to 3 times more data per subscriber, no loss of data speed

› Up to 12 times better data speeds on cell edges

0 20 40 60 80 1000

10

20

30

40

50


Use

r Thr

ough

put [

Mbp

s]

Macro+6 pico, IRC CoMPMacro+6 pico, No CoMP

+

Macro and Pico jointly decode uplink signal with

IRC-CoMP


DL coordinated scheduling

› Multi-cell scheduler› Dynamically silence PDSCH transmission› Exploit interference variations of bursty packet data› Multi-cell channel knowledge for scheduling hypothesis

–

Can be based on Rel-8 RSRP measurements

› Later DL CoMPRRU

RRURRU

= no PDSCH


Operator Managed WiFi

@ homeUse of WiFi

fixed broadband access from home

Guests @ homeVisiting your neighbors and utilize their WiFi

@ HOTSPOTVisiting café’s, airports,

hotels, …

Automatic and Seamless log-in, SIM based authentication Leveraging on existing network infrastructure

Compatible with a large number of existing phones and laptops No extra device clients needed


Small cell backhaul

LOS & NLOS wireless backhaul

Fiber, P2P GbE + other

Copper:CAT5/6 +

other

Copper:DSL

Total Small Cell Backhaul

outdoor indoor


Backhaul: Outdoor scenario

IP AggregationPublic / carrier grade IP

DSL, Fiber

LOS/NLOS

WCDMA

LTE

WiFi

Outdoor infrastructure:• LOS / NLOS wireless backhaul• Fiber, eg pWDM GbE• DSL over Legacy POTS UTP

Fixed Access Node: DSLAM / PON OLT

pRBS

C- node

Optional mobile aggregation node


Backhaul: indoor scenario

pRBS

pRBS

pRBS

Fiber/MWLeased or self-built

C- node

WCDMA

LTE

WiFi

Indoor infrastructure:• LAN UTP (CAT5/6)• Legacy telephony UTP (CAT3 or similar)• P2P Fiber, carrying GbE or Main-remote interface • Alternative transmission, eg powerline

GbE, VDSL2

GbE

GbE

IPG

RRU

RRUpRBS

pRBS

pRBS

fiber


Importance of SON in hetnet

Smart Simplicity

Deployment§ Automated planning§ Automated Preparation§ Automated Integration

Maintenance§ Automated monitoring§ Automated failure handling§ Automated administration

Optimization§ Coverage§ Capacity§ Performance§ Energy Efficiency


Self-organizing hetnet

Sim

plifi

edco

ntro

lD

istri

bute

dre

spon

sibi

lity

Network view/Policy control

Information on per need

Self-organizing

Efficient provisioning

Network perspective

Full control


Efficient provisioning

Sim

plifi

edco

ntro

lD

istri

bute

dre

spon

sibi

lity



Self-organizing

no preparation

auto-integrated

simple site work


Network perspective

Sim

plifi

edco

ntro

lD

istri

bute

dre

spon

sibi

lity



Self-organizing

KPI OAM

capacity

energy efficient

coverage


Some Scenarious for small cell deployments


The street

mRBS


Train station

mRRU


High-rise: lobby


Small office

pRBS


The squareIn

tegr

ated

Ant

enna


HetNet ensures higher performance

Remote Radio

Low power RBS

Macro


Combined – ’HetNet’

Densified macroStandard MacroU

ser T

hrou

ghpu

t [M

bps]

Improved Macro

Small cells

Coverage Probability [%]Source:

Ericsson

Combined – ’HetNet’

Use

r Thr

ough

put [

Mbp

s]Improved Macro

Densified macro

Standard Macro

Small cells


references› Landström, Sara, et. Al, “Heterogeneous Networks – Increasing Cellular

Capacity”, Ericsson Review, No.1, 2011. (http://www.ericsson.com/res/thecompany/docs/publications/ericsson review/2011/heterogeneous ne tworks.pdf)

› “Heterogeneous Networks: Meeting Mobile Broadband Expectations With Maximum Efficiency”, Ericsson White Paper, February 2012. (http://www.ericsson.com/res/docs/whitepapers/WP-Heterogeneous-Networks.pdf)

› “It All Comes Back To Backhaul: Solutions Supporting Superior End-to-End Quality Of Experience In Hetnet Deployments”, Ericsson White Paper, February 2012. (http://www.ericsson.com/res/docs/whitepapers/WP-Heterogeneous-Networks.pdf)

› “Smarter Self-organizing Networks: Intelligent Support To Address The Mobile- broadband Growth Challenge”, Ericsson White Paper, February 2012. (http://www.ericsson.com/res/docs/whitepapers/WP-Self-Organizing-Networks.pdf)

› Damnjanovic, Aleksandar, et. al., “A Survey On 3GPP Heterogeneous Networks”, IEEE Wireless Communications, June 2011.

› Erik Dahlman, Stefan Parkvall, and Johan Skold, 4G LTE/LTE-Advanced for Mobile Broadband (Academic Press), Ch. 13.4.

http://www.ericsson.com/res/thecompany/docs/publications/ericsson_review/2011/heterogeneous_networks.pdf

http://www.ericsson.com/res/thecompany/docs/publications/ericsson_review/2011/heterogeneous_networks.pdf

http://www.ericsson.com/res/docs/whitepapers/WP-Heterogeneous-Networks.pdf

http://www.ericsson.com/res/docs/whitepapers/WP-Heterogeneous-Networks.pdf

http://www.ericsson.com/res/docs/whitepapers/WP-Self-Organizing-Networks.pdf

Hetergeneous Networks IMPROVE · PDF fileSmooth spectrum refarming. GSM WCDMA LTE. WCDMA LTE....

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