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II International Workshop on Challenges and Trends on Broadband Wireless Mobile Access Networks – Beyond LTE-A
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II International Workshop on Challenges and Trends on Broadband Wireless Mobile
Access Networks – Beyond LTE-A
Alberto Boaventura
2014-11-06
4G & Beyond Changes and Challenges
Changes and …
Source: Ericsson 2013 2009 2010 2011 2012 2013
1000
1800
Voice
Data
Tota
l (U
L+D
L) t
raff
ic (
Pe
taB
yte
s)
Source: Cisco VNI 2012
12
2012 2013 2014 2015 2016 2017
6
Mobile File Sharing
Mobile M2M
Mobile Web/Data
Mobile Video
Exab
yte
s p
er
mo
nth
In 2016, Social Newtorking will be second highest penetrated consumer mobile service
with 2, 4 billion users – 53% of consumer mobile users - Cisco 2012
0,0
0,5
1,0
1,5
2,0
2,5
2009 2010 2011 2012 2013 2014*
MBB DevelopingMBB DevelopedFBB DevelopingFBB Developed
Wo
rld
Bro
adb
and
Su
bsc
rip
tio
ns
(Bill
ion
s)
Source: ITU/ICT/MIS 2014
132 89 113 147
117 161 146 103
181 170 149 151
110 59 66 43
540 min 479 min 474 min 444 min
Indonesia China Brazil USA
TV Laptop+PC Smartphone Tablet
Source: KPCB & Milward Brown 2014 Dai
ly D
istr
. Of
Scre
en
Min
ute
s
13 kbps 50 kbps
125
kbps
200
kbps
684
kbps
2009 2010 2011 2012 2013
Source: Cisco VNI (2010/2011/2012/2013)
242%
2009 ‘10 ‘11 ‘12 ‘13 ‘14 ‘15 ‘16 ‘17 ‘18
10
6
LTE UMTS/HSPA GSM;EDGE TD-SCDMA CDMA Other
Wo
rld
Mo
bile
Su
b. (
Bill
ion
s)
Source: Ericsson 2012
Lati
n A
me
rica
Ave
rage
Th
rou
ghp
ut
VIDEO BECOMES SOCIAL … DATA BECOMES VIDEO … MOBILE BECOMES DATA … TELECOM BECOMES MOBILE …
On the market demand in dense urban areas during
business hours, it has been calculated that 800
Mbps/km2 are required (BuNGee and Artists4G Projects).
The Convention Industry Council Manual guidelines
recommend 10 square feet per person. It represents 1
Million persons per km2. If all persons upload video with
64 kbps, it represents 64 Gbps/km2!
Whatsapp: Over 50bn messages every day.
Facebook: 1 billion of active users and a half of them use mobile access (488 million users) regularly.
Twitter: 50% users are using the social network via mobile.
YouTube: more than ¼ of users use in Mobile Device
Instagram: The average Instagram mobile user spent two times comparing tp Twitter.
… VIDEO, SOCIAL, CLOUD & GAMES BECOME CROWD DENSITY TRAFFIC. INTERNET OF EVERYTHING
By the end of 2014, the number of mobile-connected
devices will exceed the number of people on earth, and
by 2018 there will be nearly 1.4 mobile devices per
capita. There will be over 10 billion mobile-connected
devices by 2018, including machine-to-machine (M2M)
modules—exceeding the world’s population at that time
(7.6 billion) – CISCO VNI 2014
LTE Advanced
ITU-R M.2034 Spectral Efficiency
DL 15 bits/Hz UL 6.75 bits/Hz
Latency User Plane < 10 ms Control Plane < 100 ms
Bandwidth ITU-R M.2034 40 MHz ITU-R M.1645 100 MHz
ADVANCED
Coverage C
apac
ity
SmallCells
High order MIMO Carrier Aggregation
Hetnet/CoMP
LTE
LTE –A
3GPP TR 36.913
3GPP Release 8
3GPP Release 10
RELEASE 8/9 RELEASE 10/11 RELEASE 12/13
20 MHz OFDM SC-FDMA DL 4x4 MIMO SON, HeNB
Carrier Aggregation UL 4x4 MIMO DL/UL CoMP HetNet (x4.33) MU-MIMO (x1.14)
Small Cells Enh. CoMP Enh. FD-MIMO (x3.53) DiverseTraffic Support
LTE Roadmap
Carrier Aggregation Intra & Inter Band
Band X
Band y
Multihop Relay
Multihop Relay
Smallcells Heterogeneous Network
Colaboration MIMO (CoMP) e HetNet
High Order DL-MIMO & Advanced UL-MIMO
C-plane (RRC)
Phantom Celll
Macro Cell F1
F2
F2>F1
U-plane
D2D
New Architecture
METIS PROJECT PREMISES (SOURCE: ETSI/ERICSSON) METIS: 29 PARTNERS
5G Vision and Timeframe
ITU-R´s docs paving way to 5G:
IMT.VISION (Deadline July 2015) - Title: “Framework and overall objectives of the future development of IMT for 2020 and beyond”
Objective: Defining the framework and overall objectives of IMT for 2020 and beyond to drive the future developments for IMT
IMT.FUTURE TECHNOLOGY TRENDS (Deadline Oct. 2014)
To provide a view of future IMT technology aspects 2015-2020 and beyond and to provide information on trends of future IMT technology aspects
EU (Nov 2012)
China (Fev2013)
Korea (Jun 2013)
Japão (Out 2013)
2020 and Beyond Adhoc
Exploratory Research Pre-standardization Standardization activities Trials and Commercialization
2012 2013 2014 2015 2016 2017 2018 2019 2020
WRC15 WRC12 WRC19
Mobile and wireless communications Enablers for the Twenty-twenty Information Society
5G Potential Technologies
1=0º
1=45º
30
210
60
240
90
270
120
300
150
330
180
...
p1
p2
pN
Native M2M support A massive number of connected devices
with low throughput; Low latency Low power and battery consumption
hnm
h21
h12
h11
Higher MIMO order: 8X8 or more System capacity increases in fucntion of
number of antennas
Spatial-temporal modulation schemes SINR optimization Beamforming
Enables systems that illuminate and at the same time provide broadband wireless data connectivity
Transmitters: Uses off-the-shelf white light emitting diodes (LEDs) used for solid-state lighting (SSL);
Receivers: Off-the-shelf p-intrinsic-n (PIN) photodiodes (PDs) or aval anche photo-diodes (APDs)
C-plane (RRC)
Phantom Celll
Macro Cell
F1 F2
F2>F1
U-plane
D2D
Phantom Cell based architecture Control Plane uses macro network User Plane is Device to Device (D2D) in
another frequency such as mm-Wave and high order modulation (256 QAM).
Net
Radio
Core
Cache
Access Network Caching Network Virtualization Function Cloud-RAN Dynamic and Elastic Network
Universal Filtered Multi-Carrier (UFMC) : Potential extension to OFDM ;
Filter Bank Multi Carrier (FBMC): Access sporadic, short bursts, increased robustness, support QAM symbols and minimization problems offset; sustainability fragmented spectra.
High modulation constellation
MASSIVE MIMO SPATIAL MODULATION COGITIVE RADIO NETWORKS VISIBLE LIGHT COMMUNICATION
DEVICE-CENTRIC ARCHITECTURE NATIVE SUPPORT FOR M2M CLOUD NETWORK & CACHE NEW MODULATION SCHEME
5G Non-Orthogonal Waveforms for Asynchronous Signalling (5GNOW)
New protocol for shared spectrum rational use
Mitigate and avoid interference by surrounding radio environment and regulate its transmission accordingly.
In interference-free CR networks, CR users are allowed to borrow spectrum resources only when licensed users do not use them.
... Challenges
ITU-R M.2078 projection for the global spectrum requirements in order to accomplish the IMT-2000
future development, IMT-Advanced, in 2020.
531 MHz 749 MHz
971 MHz
749 MHz
557 MHz 723 MHz
997 MHz
723 MHz
587 MHz 693 MHz
1027 MHz
693 MHz
Region 1 Region 2 Region 3
MORE SPECTRUM NEW TECHNOLOGY & INFRASTRUCTURE SPLIT CELL & SITE DENSIFICIATION
𝑪 𝒃𝒑𝒔 ≤ 𝑩(𝑯𝒛) ∙ 𝒍𝒐𝒈𝟐 𝟏 + 𝑺𝑰𝑵𝑹
Smallcells
Heterogeneous Network
hnm
h21
h12
h11
Mobile operation needs spectrum below 6 GHz,
but there is no enough around world.
Interference with exiting services: cleanup cost,
interference mitigation
High spectrum cost: The average license cost in
new spectrum auctions ranges around 100-700
million of Reais per 10 MHz FDD block
Spectrum Refarming
Spectral Efficiency
New infrastructure investment
Technology life cycle and adoption
Market Scale
New site legal barriers
Tax barriers
New site investment
Interference control and mitigation
Backhaul capillarity
Carrier Aggregation
High Order MIMO
Cell Site Densification
Spectrum Challenges
Spectrum Requirement
Spectrum Requirements per Operator (Rysavy Research – February 2010):
The expectation is to be needed over than 200 MHz per operator in 2016.
Band UL (MHz)
DL (MHz)
Width (*) WRC 3GPP (LTE) Anatel
450 MHz 451-457 461-468 14 MHz 2007 Band 31 Res 558/2010
700 MHz 703-748 758-803 90 MHz 2007 Band 28 Res 625/2013
850 MHz 824 - 849 869 - 894 50 MHz 2000 Band 5 Res 454/2006
900 MHz 898,5 - 901; 943,5 - 946
907,5 - 915; 952,5 - 960
10 MHz 2000 Band 8 Res 454/2006
1800 MHz 1.710-1785 1805-1880 150 MHz 1992/ 2000
Band 3 Res 454/2006
2100 MHz 1920-1975 2110-2165 110 MHz 2000 Band 1 Res 454/2006
2600 MHz 2500-2570 2620-2690 140 MHz 2007 Band 7 Res 544/2010
3500 MHz 3400-3600 (TDD) 200 MHz 2007 Band 42 Res 537/2010
Brazil: 330 MHz (Res 454/2006) , 204 MHz (Res 544/2010)., and 80 MHz (Res 625/2013)
But due CAP constraint, only 140-160 MHz per operator is allowed.
Spectrum Aggregation
Sensing and Cognitive radio technologies for spectrum sharing
Offloading with fallback techniques to exclusive global bands, e.g. for mobility/roaming.
ITU-R forecasts a need of 1280 to 1720 MHz in the medium term for IMT (before 2020)
Global IMT spectrum of 715 MHz currently available, plus <300 MHz on a regional basis
WRC’12 confirmed the intention to allocate more spectrum to IMT in the 700 MHz band (~90 MHz)
FCC: Make 500 MHz of spectrum newly available for broadband within 10 years
European Comm.: 1200 MHz (incl. exist. 625 MHz) to be allocated to mobile broadband by 2015
Need to consider shared spectrum: Unlicensed spectrum, unlicensed secondary usage or Licensed Secondary Access (LSA) e.g. in TV white space,
WORLD SPECTRUM FORECAST SPECTRUM PER OPERATOR SPECTRUM IN BRAZIL
LICENSED SPECTRUM NEW SPECTRUM NEW TECHNOLOGIES FOR SPECTRUM MANAGEMENT
ITU-R M.2078 projection for the global spectrum requirements in order to accomplish the IMT-2000
future development, IMT-Advanced, in 2020.
531 MHz 749 MHz
971 MHz
749 MHz
557 MHz 723 MHz
997 MHz
723 MHz
587 MHz 693 MHz
1027 MHz
693 MHz
Region 1 Region 2 Region 3
Spectrum Management
Frequency under 1 GHz has a good Indoor
propagation. But lack bandwidth for
capturing mobile broadband traffic.
90 MHz 150 MHz
200 MHz
13 GHz
700 MHz 1800 MHz 3500 MHz mmWave
INDOOR TRAFFIC INDOOR LOST PERFORMANCE
39%
32%
14%
4%
11%
In Car
At Home
At Work
Travelling
Others
0 bps/Hz
4 bps/Hz
8 bps/Hz
12 bps/Hz
-130 dBm -110 dBm -90 dBm
3GPP (LTE) Shannon
Outdoor Indoor
-50%
50% of voice traffic and 80% of data traffic are
performed in indoor environment;
Building Penetration Loss varies around 10-20 dB,
that reduces at minimum of 50% overall performance
of outdoor macro sites;
SPECTRUM DILEMMA: COVERAGE VS CAPACITY
Better propagation
Ban
dw
idth
Voice Originating Call Amount of Bandwidth
REFARMING
F1 F2
Scenario 1
Same coverage F1 = F2
Scenario 2
F2 has smaller coverage F2> F1
Scenario 4
F2 Is used to hot spots F2>F1
LOW DENSITY TRAFFIC & SPECTRUM
0,058
0,121
0,684
450 MHz
700 MHz
1800 MHz
DUAL LAYER & CARRIER AGGREGATION
The high cost of spectrum and the consolidation of
mobile broadband with the decline and migration of
legacy voice services on 2G to 3G in the coming
years, raises the possibility of immediate use
bands of GSM as the 1800 MHz for LTE. Different azimuth F1 = F2 or F1 F2
Scenario 3
Bands below 1 GHz, such as 700 MHz are applicable for low
density traffic, like: M2M; product in initial lifecycle;
suburban and rural areas;
When traffic is becoming more density, there is no difference
between high and low spectrum band
Current 1800 MHz used for GSM/GPRS
Carving for LTE utilization
BCCH MA LIST BCCH MA LIST
BCCH MA LIST BCCH MA LISTLTE
New Technology & Infrastructure
Challenges
Equation:
Data
Voice 2G (GSM, GPRS, EDGE)
3G (UMTS, HSPA+)
900 MHz (B8)
1800 MHz (B3)
2100 MHz (B1)
850 MHz (B5)
The Mobile Operation Planning involves the assessment of the complex equation:
Service (demand characteristics for voice and data) vs Technology (2G, 3G and 4G or otherwise) vs Spectrum
(900, 1800, 2100, 2600 MHz or otherwise), where should seek cost optimization not only present but future
disruptive scenario with lack of fundamental resource: spectrum.
Service Technology Spectrum
2600 MHz (B7)
700 MHz (B28)
450 MHz (B31)
4G (LTE)
CDMA/TDMA
Technology Life Cycle Ecosystem
Total Cost Ownership Customer Experience
Terminal Penetration & Cost Capacity&Spectral Efficiency
Service Support Level of Terminal Subsidy
License & Network Cost License Obligation
Ecosystem Bandwidth Limitation Coverage & Capacity
Interference Level of Terminal Subsidy
Constrains &
Decision Criteria
Planning Framework
Data Voice
2G 3G 4G (LTE)
900 MHz 1800 MHz 2100 MHz 2600 MHz
Other
Data Voice
2G 3G 4G (LTE)
900 MHz 1800 MHz 2100 MHz 2600 MHz
VISION DEFINITION FRAMEWORK DEFINITION
• Service characteristics requirements, traffic requirements
Demand Analysis
• Network service assessment, Capacity evaluation, System growth opportunity, Split cell vs interference, Spectrum availability, License obligation, New technologies
System Analysis
• Technology life cycle, Ecosystem analysis, Spectral efficiency
Technology Analysis
• Scenario options, Total Cost Analysis, Spectrum availability, License obligation,
Scenario Analysis
Network Planning
Demand
Voice & Data
𝒎𝒊𝒏 𝑻𝑪𝟏 𝒊
(𝟏 + 𝑲)𝒊−𝑿, ⋯ ,
𝑻𝑪𝑵 𝒊
(𝟏 + 𝑲)𝒊−𝑿
𝑵
𝒊=𝑿
𝑵
𝒊=𝑿
⇒ 𝐓𝐚𝐫𝐠𝐞𝐭 𝐒𝐜𝐞𝐧𝐚𝐫𝐢𝐨
Scenario 1
Scenario N
...
New Frequency New Technology New Site
Long term scenario
Required for service and technology evolution
Required for long term spectrum management
Service and Strategic Needs
Plan Acquire Maintain Renew/ Dispose
System Capacity & Cost
0 1 2 3 4 5 6 7
200kHz
25 TRX
3,84MHz
1 WCDMA Carrier
r
R
D
i j
i
j D
r
R
D
i
j
i
jD
Codec FR D = 4 / Sector = 3
Reuse = 4 x 3 #Ckt/Sector= 2x7=14
Codec AMR 12.2 127 Walsh Codes
Reuse = 1 %SHO=20%
#Ckt/Sector = 64
24 Erl/BTS 160 Erl/NodeB
r
R
D
i
j
i
jD
PRBs
...
7 S
ymb
ols
12 subcarriers
25 Resource Blocks
700 Erl/eNB Codec AMR 12.2
25 PRBs - 300 REs 200 -250 users/ Sector
2G (GSM) 3G (UMTS/HSPA) LTE
Sysm Capacity & Spectral Efficiency (Voice Capacity @ 5 MHz)
NEW CELL SITE CAPEX SPECTRUM COST NETWORK COST
25% 45% 50%
52% 38% 35%
23% 17% 15%
Rooftop 30m Tower 50m Tower
Infra BTS Transport
Source: Planning Area, Oi, 2012
New Cell Site represents a huge impact in Wireless Operation total cost.
System capacity (Spectral Efficiency) in single site is the most important attribute.
The 2G spectrum consumption is faster than 3G as voice traffic increases. Spectrum is a lack and valuable resource. 10 MHz can cost
500-1 Billion of Reais.
0 MHz
10 MHz
20 MHz
30 MHz
10 Erl/BTS 50 Erl/BTS 90 Erl/BTS 130 Erl/BTS
2G
3G
+14 MHz
Cost Perspective
$$$
$$$
$$$
$$$
$$$
0,0 kErl 2,0 kErl 4,0 kErl 6,0 kErl
2G (4/4/4)
3G (1/1/1)
3X
The cost per Erl to support voice on 3G is invariably cheaper than 2G .
6 kErl (~ 300k users), is 3 x the cost 2G.
LTE Access Network is 7-10 times cheaper than 3G per Mbps.
Customer Experience & Technology Lifecycle
0 Mbps
2 Mbps
4 Mbps
6 Mbps
2009201020112012201320142015
América Latina
America do Norte
Europa Ocidental
Brazil
It is expected that the average grows exponentially. In Brazil, the growth is
82% year-on-year by 2015 according to Cisco
APPS & MARKET TRENDS
QoE is the main motivation of churn and it will remain a key challenge for mobile operators and may in fact rise as the
wireless value chain becomes increasingly decentralized.
ITU-T Rec. P.10/G.100: The overall acceptability of an application or service, as perceived subjectively by the end-user.
QOE DEFINITION
Req. SLA QoS
QoE SLA KQI KPI
t t+ t- throughput
u(t)
u(t+)
u(t-)
u”(t) <0
Utility=QoE
Utility function perfectly captures user satisfaction in terms of what they are
willing to expect and pay.
UTILITY FUNCTION VS QOE
Users have more sensibility when lose than when win.
Competitive Pressure
Delighted
Extremely Dissatisfied
Fully Functional Dysfunctional
Attractive
Time Expected
KANO´S MODEL
Customer satisfaction has a positive correlation with how the product is functional. I.e., dysfunctional => bad experience; functional => Delighted
Customer Experience
Technology Lifecycle
2013 2019E CAGR
2013-2019
Worldwide mobile subscriptions* 6,700 9,300 6%
– Smartphone subscriptions 1,900 5,600 20%
– Mobile PC, tablet &modem r subs 300 750 15%
– Mobile broadband subscriptions 2,100 800 25%
– Mobile subscriptions, GSM/EDGE- 4,300 1,200 -20%
– Mobile subscriptions, UMTS/HSPA 1,600 4,800 20%
– Mobile subscriptions, LTE 175 2,600 55%
Source: Ercisson Mobility Report 2013
SUBSCRIPTIONS RATE & FORECAST ASSET MANAGEMENT
Network Planning
Demand
Voice & Data
Scenario A Expand with
existing technology
Scenario B Start to change to a
new technology
Scen. A Scen. B
Year X
Ecosystem Cost
Spectrum Cost
𝑻𝑪𝑨 𝑻𝑪𝑩
Choosen Scenario must be which will
minimize VP of TCO.
LIFECYCLE & TERMINAL SUBSIDY
Utility Budget Restriction
LTE
HSP
A+
𝑴𝑹𝑺 =
𝝏𝑼𝝏𝑳𝑻𝑬𝝏𝑼
𝝏𝑯𝑺𝑷𝑨 +
𝒑𝑳𝑻𝑬𝒑𝑯𝑺𝑷𝑨+
≤ 𝑴𝑹𝑺
Utility Function
Budget Restriction
Subsidy level can minimize the TCO and it must be calculated as a function of how user is willing to pay
for more throughput (Utility Function) and cost of spectrum and network (Asset Management)
Split Cell and Site Densification
Challenges
Handling High Density Traffic
2013 2014 2015 2016
2017
2018
2019
2020
0,0 Mbps/km2
500,0 Mbps/km2
1000,0 Mbps/km2
1500,0 Mbps/km2
2000,0 Mbps/km2
0,250 km0,350 km0,450 km0,550 km
DOWNTOWN: HIGH DENSITY TRAFFIC
Coverage Radius
Capacity 2015
Capacity 2016
Capacity 2017
A +63%
C
D
+61%
+54%
B
Green line represents the system capacity density.
The capacity associated to coverage grid can capture the demand from 2013 till 2014 – Point A;
However, for 2015 it is needed to increase 63% the number of sites, changing the exiting grid – Point B;
In 2016 and 2017, they require more 61% and 54% more sites respectivelly;
In that time, SmallCells are more appropriated infrastructure to save CapEx and OpEx;
TECHNOLOGY ALTERNATIVES AND TOTAL COST OPERATION
$$$
$$$
$$$
$$$
$$$
$$$
1 x 3 x 5 x 7 x 9 x2600 MHz (10) +1800 MHz (5) +1800 MHz (10) SmallCell
2015 2016 2017 2018 2019 2020
Notes: 2600 MHz (10) : Basic Scenario; +1800 MHz (5): Additional 5 MHz using 1800 MHz in Basic Scenario coverage; +1800 (10): Same as above, but using 10 MHz; SmallCell: SmallCell using 2600 MHz with 10 MHz for bandwidth;
TIMES BASIC SCENARIO COVERAGE CAPACITY
TCO
A B C
Indifference between Macro
1800 & 2600 MHz
Macro LTE 1800 MHz for
coverage
Dual layer Macro LTE 1800
& 2600 MHz
181 265 890
SmallCell 2600 MHz
𝑴𝒃𝒑𝒔
𝒌𝒎𝟐
New Architecture: Cloud RAN
Fronthaul Interface Hardware
Backplane
Backhaul Interface Hardware
Hardware Poll
Virtualization Layer (Ex.: Hypervisor/VMM)
VM BBU 1 VM BBU N Core
Network
Cache & Local
Breakout ...
O&
M/C
on
tro
l/O
rch
es
tra
tor
Fronthaul: CPRI, OBSAI, ETSI ORI
Internet
RRU/ RRH
Radio Unit
Network Datacenter
Only Radio Unit
Backhaul IP
RRU/ RRH
Backhaul
Core Network
BBU BBU BBU
Internet
RRU/ RRH
RRU/ RRH
GbE
Existing Deployed Topology
Fronthaul
Internet
V-BBUs V-Core
RRU/ RRH
RRU/ RRH
RRU/ RRH
CPRI/ OBSAI
Cloud RAN Topology
DEPLOYMENT PARADIGM CHANGE
PRINCIPLES AND ADVANTAGES
ARCHITECTURE
Network Function Virtualization
Elastic & liquid Resources
Operational Flexibility
Reduces space and power consumption
Reduces CapEx, OpEx and delivery time
Software Defined Network
Creates an abstraction layer for: controlling; faster development ; system service orchestration and overall system evolution;
Open Development Interface
Creates an open environment for new development;
Catalyzes new SON & interference mitigation functionalities support;
Site aquisition: Given the limitation on the scope of the small cell, you have to know exactly where the traffic is generated and get the rights to install that exact spot.
New types of leases should be developed. The expectation for the installation of Small
scale is Cells that are an order of magnitude greater than the macro cells .
Visual Polution: Due a number of SmallCells, the shape and format may impact in acceptance to install in building and public facilities.
Small cell radius of coverage is reduced compared to macro, it is necessary to locate accurately the traffic sources;
The installation of small cell (site acquisition) occurs with small error regarding the location planned.
Heterogeneous RF planning requires how traffic will be handled by each layer.
For maximum result from the limited range making the reuse of the spectrum.
Reuse requires a plan of distribution of the cells very well done.
IP Access (MPLS-TP, Metro Eth, MDU) , Giga-Ether over 150 Mbps per BTS
Required necessarily optical fiber, but Radio NLOS can be alternative for higher capillarity
New synchronism support (IEEE 1588, SyncE) e-ICIC requires synchronism deviation around
1.5 s. For CoMP, Latency must be below 1 ms New interface other than IP: CPRI
Backhaul & Fronthaul
Pain Points
Downlink: Terminal camped on in macro is interfered by a small cell. And terminal served by a small cell to connect the edge of cell will be interfered by the macro cell.
Uplink : one terminal connected in macro and close to the cell border creates strong interference in a small cell next. And large number of connected terminals in small cells generate uplink interference in the macro cell.
They both are addressed with sofisticated mechanisms like ICIC, e-ICIC, Fe-ICIC, and CoMP
Interference Mitigation
Mobility device in idle state impacts the relative load between layers and battery consumption and frequency of handovers.
Increase in handovers due to the small size of the cells increases the risk of dropped calls (Dropped Call Rate),
Devices in connected state may need to HO to a small cell and, if they are on different frequencies, will need efficient scheme discovery of small cell that minimizes the impact on battery consumption.
Traffic/Capacity balancing with several resources and frequencies
Mobility Management
Planning Deployment and Rollout
The range in the number of radio stations in the layer of Small Cells should be an order of magnitude larger than the current one.
The way to optimize and operate should fit depending less manual intervention. Resources SON (Self Organizing Networks) will be important to maintain a good performance.
Service Availability: Internal battery must be required for accomplishing service SLA requirements.
The licensing cost (TFI/TFF) was a recent issue but still exist for SmallCells with higher power
Operational