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IMPROVE
DENSIFY
ADD
Hetergeneous Networks
HETNET
HetNet | Public | 2012-03-23 | Page 2
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
HetNet | Public | 2012-03-23 | Page 3
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
HetNet | Public | 2012-03-23 | Page 4
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 | Public | 2012-03-23 | Page 5
Hetnet strategy
Required Capacity
Improve
AddDensify
Current C
apacity
HetNet | Public | 2012-03-23 | Page 6
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
HetNet | Public | 2012-03-23 | Page 7
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
HetNet | Public | 2012-03-23 | Page 8
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
HetNet | Public | 2012-03-23 | Page 9
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
HetNet | Public | 2012-03-23 | Page 10
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!
HetNet | Public | 2012-03-23 | Page 11
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
HetNet | Public | 2012-03-23 | Page 12
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)
HetNet | Public | 2012-03-23 | Page 13
Interference and traffic management
Inter-RAT Multi-cell
coordination
Inte
rfere
nce
mitig
atio
n
Inte
r-fre
quen
cy
Intra-frequency mobility
HetNet | Public | 2012-03-23 | Page 14
Interference Suppression a key HetNet feature
Interference Suppression a key feature for HetNets with unpredictable sources of interference
HetNet | Public | 2012-03-23 | Page 15
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 | Public | 2012-03-23 | Page 16
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
HetNet | Public | 2012-03-23 | Page 17
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
Coverage Probability [%]
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
HetNet | Public | 2012-03-23 | Page 18
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
HetNet | Public | 2012-03-23 | Page 19
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
HetNet | Public | 2012-03-23 | Page 20
Small cell backhaul
LOS & NLOS wireless backhaul
Fiber, P2P GbE + other
Copper:CAT5/6 +
other
Copper:DSL
Total Small Cell Backhaul
outdoor indoor
HetNet | Public | 2012-03-23 | Page 21
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
HetNet | Public | 2012-03-23 | Page 22
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
HetNet | Public | 2012-03-23 | Page 23
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
HetNet | Public | 2012-03-23 | Page 24
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
HetNet | Public | 2012-03-23 | Page 25
Efficient provisioning
Sim
plifi
edco
ntro
lD
istri
bute
dre
spon
sibi
lity
Network view/Policy control
Information on per need
Self-organizing
no preparation
auto-integrated
simple site work
HetNet | Public | 2012-03-23 | Page 26
Network perspective
Sim
plifi
edco
ntro
lD
istri
bute
dre
spon
sibi
lity
Network view/Policy control
Information on per need
Self-organizing
KPI OAM
capacity
energy efficient
coverage
HetNet | Public | 2012-03-23 | Page 27
Some Scenarious for small cell deployments
HetNet | Public | 2012-03-23 | Page 28
The street
mRBS
HetNet | Public | 2012-03-23 | Page 29
Train station
mRRU
HetNet | Public | 2012-03-23 | Page 30
High-rise: lobby
HetNet | Public | 2012-03-23 | Page 31
Small office
pRBS
HetNet | Public | 2012-03-23 | Page 32
The squareIn
tegr
ated
Ant
enna
HetNet | Public | 2012-03-23 | Page 33
HetNet ensures higher performance
Remote Radio
Low power RBS
Macro
Coverage Probability [%]
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
HetNet | Public | 2012-03-23 | Page 34
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.