Download Creating the hetnet

I
xisting mobile nefworks are not designed
networks and provide them with greater capacity
to cope with data traffic volumes that are
doubling year on year. Not only must their
in a more targeted way, thus reducing both capital
Creating
the hetnet
and operating costs. Wi-Fi is important because it
provides unlicensed free-to-air transmission. This
Incorporating Wi-Fi and mobile small cells into a
traditional cellular network results in a 'heteroge-
gives operators a free ride to off-load data calls
onto the nearest available Wi-Fi hotspot (which is
neous network' or'hetnet'. However, until the
long term, switch to a more data-centric network
infrastructure.
typically connected to a fixed line network) thus
operators lost sight of the traffic and hence revenue
liberating airspace for voice communications.
opportunity when users accessedWi-Fi hotspots
present voice-oriented architecture cope with the
short-term data problem but they must, over the
To cope with the immediate data flood, operators
development of the Hotspot 2.0 standard (seeight),
need to use their available spectrum more efficiently
'cells'.
This
by increasing the density of their radio
from their smarphones. This is presently less of a
problem for African mobile operators because of
has led to the development of relatively low-powered
relatively low consumer data usage.
cellular base stations or small cells that can support a
A recent Informa study for satellite operator
variety of generations of mobile transmission
iDirect found Africa as a whole has the world's
technologies and frequencies, often integrated with
Wi-Fi. Depending on their power, they are called
lowest figure for data as a percentage of total mobile
revenues.A year ago this was just below 11 per cent,
pico-, femto- and microcells. This range makes them
but there was 17.5per cent growth n2QI1,
suitable for both indoor and outdoor operation.
will have accelerated today because of the greater
Stephen Weinstein, IEEE Life Fellow and
consultant, says small cells can minimise the shared
bandwidth requirement for high-speedserviceq boost
and this
availability of smart devices and with some
operators launching LTE services.
Small cell technology could increase compefition
service in smaller geographic areas, and add network
capacity in areas with dense wireless usage. "These
befween fixed and mobile operators, enabling some
to provide accessfor the first time. For example,
small cellular base stations are especially suitable
Mauritius-based active ffiastrucfure
indoors and along highways, and offer a readily
IPX Extenso is using small cell technology from
available economic solution that can be incorporated
ip.access,ViaSat, and pan-African satellite operator
into the current infrastructure to help handle the
RascomStar-QAF to detver mobile coverage and
world's evolving high-speed wireless needs."
fixed telephony accessto around 50 sites in DR
Congo with a gateway inBrazzavilTe. Installation
Small cells co-exist within existing cellular
COMMUNICATIONS
AFRICANWIRELESS
SOUTHERN
operator
and the first pilot service wifl begin this zummer
with plans to widen the deployment in 2013.
The firms also expect to include at least l0 more
countries in the central African region. ip.access
reckons its experrise in small cell deployment help_
ed the partners to create an affordable end_to_end
system that will bring voice and internet access ro
previously unconnected communities. Rascomstar_
QAF adds *rat its services were developed to provide
affordable universal access telephony in rural and
remote areas, especially for low ARpU communi_
ries. "We believe that we have a seryice that meets
the needs of a region underserved by mobile and
indeed fixed telephony," says CEO Faraj Elamari.
Hotspot
2.0
Small cell technology has evolved from unlicensed
spectrum technology (Wi-Ft) that addressed mainly
consumer home networking. It moved into the
enterprise to cyeate Wi-Fi hotspots and wireless local
area networks powered either by Wi-Fi or licensed
specffum mobile technology. More recently, Wi_Fi
has permeated the carrier space where it is
increasingly seen as essential in relieving network
congestion by oflloading data traffic via Wi_Fi to
the fixed line backfiaul network. In the future, small
cell architecture may evolve to include Bluetooth
and other 'Personal Network' technologies.
At Mobile World Congress earlier this year, Cisco
said it was embedding Wireless Broadband Alliance_
approved next-generarion hotspot (NGID technology
in its carrier Wi-Fi products. It claims that this will
enable cellular-like roaming for Wi-Fi networls.
The NGH initiative is based on the new Hotspot
2.0 specification established by the Wi-Fi Alliance.
Among the equipment makers that support it are
Cisco, Accuris Networls, Aruba Networks, BelAir
Networls, and Ruckus Wireless. Under Hotspot 2.0
Thisunobtrusive
Radwin
3G/4G
small
cellsit
above
a non-line-of-sight
backhaul
antenna,
allowingoperators
totarget
precisely
increases
incell
density
andtherefore
network
capacity
in areas
thatsuffer
congested
alrwaves.
The ITU saysDigital Dividend 7}}WIzfrequen_
ciescan be rzusedfrom 2015for mobile telephony
in Region 1, which includesAfrica and Europe.
Although market conditions and topologiesin
Africa differ, there may be somelessonsto be
drawn from a recentstudy of the use of 700MHz
in the UK commissionedbythe regulator Ofcom
and producedby Real Wireless.
The report said: ,,Both lower frequencyand
higher frequency spectrumhave a role to play
in future mobile capacity,and that additional
(700MHz) spectrum acts in combination with
other sourcesof capacity such as small cells,
offload and technology enhancements,with
each approachbenefiting from the presence
of the others,rather than as substitutes.,'
Noting that the timeframe introduces
uncertainty in some issues,Real Wireless
estimatesthere will an averageof 12 percent of
outdoor rma;[ sellsin rural areacomparedto gl
per cent in urban areas.It saysthat theseact to
reducethe number of additional macrocellsites
(and associatedcosa) which would be otherwise
required.It addsthat they provide cheaptargeted
coverageas well as greater flexibility to
accommodatechangesin centresof demand.
Real Wirelesse4pectsthe use of indoor small
cells,either Wi-Fi or mobile, for traffic off_loadto
rise from 30 to 40 per cent to as much as 60 per
centby 2030.This would be costly and could limit
oflload deployments.
Howwer, this could be mitigatedby the release
of 700MIIz specrrumby 2020rather t}ran2026.
It's tlaimed that early releasecuts network costs
15-41per centcompilredto lI-27 per cent,and
site costsby l8-S2per cent. Real Wirelesssaysthis
is becausethe 700MIIz band was betweenfive
and nine per cent of relevantspectrumin 2030,
"but yieldqgreaterbenefitsdue to it distinctive
physicalproperties".
devices can connect securely and automatically to
Wi-Fi networks without consumers having to key
in user-names or passwords. It also allows mobile
operatorsto managesubscriberand serviceinforma_
tion while integrafing2G/3G/4G LTE and femtocell
(icensed)networkswith Wi-Fi (unlicensed)nerworks.
operators, who increasingly have their own or
It claims the gatewaydeliversseamlessexperiences
partner hotspot networks, to off_load many more
acrossmultiple heterogeneousaccessnetworks.
users from their busy mobile broadband networks.
New servicessuchas mobile video streaming
Hotspot 2.0 access points feature similar levels of
require much higher data rates(l0lvlbpg than are
security to the cellular network, including end_to_end generally
availableon2G/3G networks.In addition,
radio link encryption and SIM authentication, thus
mobile operatorsneedto expandcoveragecost_
allowing operators to maintain and conftol the user,s
effectively.Tloaccommodatebottr of these,African
Wi-Fi sessions. Cisco says it has deployed more than
and Europeanregulatorsare sellingmore spectrum
12 million access points, and that most of them are
in the 800MHz and2.6GHzbands,and someare
upgradeable to support NGH. Its new Small Cell
allowing operatorsto use existingfrequencies_ a
Gateway,based on the Cisco ASR S0A Seriesmobile
processingknown as ,refarming'.From 2015,they
multimedia core router, has been designed to enable
will be also to apply for the 700MHz band, popular
in the US as TV broadcasterssudtchfrom analogue
to digital transmissionand vacatethe frequencies.
3Gl4c SmallCell
RADWINSmallCell
NIOSBackhaulsolution
I
Channef
width
The sub-lGHz bands are of particular interest to
mobile operators who have to cover large distances
and/or sparse populations. Howwer, channel uddth
also affects performance; for instance. a 5MHz
channel can carry half the traffic of a l0MHz
channel. Nokia Siemens Networks (NSIrt) recently
claimed a throughput speed record for LTE of
l.3Gbps, but that required 60l\/ftIz of bandwidth.
This is important to the nature of the network
traffic. Generally, users want a wide channel for
video and voice because this would give them the
clearest slglal. But they could accept a narower
channel for emails and text messages. This will
have
implications for the price governments can hope
to
extract from frequency auctions, as well as operators,
tariff strategies.
African opelators on the whole are still struggling
to increase their coverage, but some want to reduce
churn using value-added seryices as inducement. This
uzually increases the data traffic on their networks
and, over time, will push operators towards IJIE
with
SOUTHERN
AFRICAN
WINiITSS
COMMUNICATIONS
,.
I
|l
tl
bring is of extreme value," says Nativ.
oppornrnity but also a big challengeasthey haveto
He adds that all this doesn't necessarily mean they
from
what
of
requirements
set
different
meet a very
they areusedto in ttre macro-cellularenvironment." have accessto fibre: "Many operators tell us that
ffenching across a street in a big town is sometimes
Backiraulproductsfor small cellsmust not only
so costly that wireless back*raul is far more costbe smallerand cheaper,but they haveto operatein
effective." And even when fibre does reach abuilding,
argues
Paolini
RF
environments.
more challenging
he believes the rent required by the landlord to run it
that operatorswill needto combineline of sight
up the building to the cell site may be too high.
(LOS) and non-LOS (NLOS) technologiesin their
According to Radwin, deployingNLOS wireless
networlc to provide the right mix of coverageand
linl6 will reduce ttre number of small cells
bacltraul
and
scalable
a
sustainable
capaaty,and to support
needed for an area, but this requires special expertise
businesscase.
and use of new technologies, operations, and skills.
Adi Nativ, marketing and businessdevelopment
Rural areas offer a different challenge. In the
\lP for wirelessbroadbandequipmentmakerRadwin,
study mentioned above, the
Informa-iDirect
techback*raul
ideal
agrees:"Fibre is obviouslythe
researchers found fixed line backhaul almost
nology for any cell site.Howwer, alarge number of
certainly impractical, inflexible, or too costly in
cell sitesnowadaysaxeconnectedusing wireless
back*raul,mostly in caseswhere fibre is not available sma[ cells deployments outside densely populated
or too costly to be trenchedto the cell site location." areas. This leaves microwave and satellite, both of
which are widely deployed in bacl*raul networls.
He goeson to point out that how many sitesuse
"Modern TDMA-based systems can rapidly delivfibre bacl*raul dependson the operator'saccessto
er the highly-cost-effective, carrier-class, two-way allit, the geographyof the deployment,site location,
distancefrom nenvork, regulatory iszues,labour and IP connectivity with shared bandwidth that is ideally
suited to small cell environments," says the study.
leasingcosts,municipal rules, etc. This becomes
"Payback can be achieved in as little as two years,
evealmore complexwith small cellsback*raul'
and TCO is highly competitive due to significantly
"Many small cells will be deployed on
reduced capex relative to competing solutions, and
streetfurniture such as traffic lights, light poles,
its all-digital IPlEthernet end-to-endenvironment.
opex (is) in line with similar network deployments."
objects.
other
street-level
Market researchand practical experiencesuggest building walls and
This is good news for African operators, particareas,
urban
in
dense
be
deployed
will
Most
for
smallcell
that LTE adoption is the key driver
for those who have obligations to expand rural
ularly
they
and
coverage
capacity
extra
the
where
SK
pioneer,
Sweden's
LTE
deployments.World
Telecom,recentlysaid it had 500,000LTE
subscribers.It will launch femtocells to provide
indoor support for the LIE nenvorks it's aiming
to build in 84 cities.Thesewill be integratedwith
l, Netwlk Registcranablesoperatorsto roll out
Becausesmall cells generally sit within areas
Wi-Fi in a singleaccessPofu, and will havePoE
private
consumersmall cell servicesquicHy by
coveredby 2G/3G/4G networks, it is
ftrower-over-Ethernet)so that they can be deployed
the gapbetweenthe small cells and the
bridging
each
other,
of
aware
important for them to be
where power cabling isn't available.
businesssystems.As eachsmall cell is
operator's
management
network
for
operational
both
Taking a different line, WiMAX/4G specialist
and self-configures,the NOS obtains
on
switched
purposes.
for
billing
and
reasons
data
oFload
its
mobile
launched
Alvarion recently
all the information requiredabout the cell and its
Macro cell networls are alteadylargely selfsolution. This is said to be basedon carrier-grade
registeredhandsets.Ttris dita is then fed directly
optimising in that they monitor frequancies,
two-way beamformingWi-Fi technologyto offer fast
to the operator'sexistingbusineis systems.
power,
automatically
and
and
volumes
traffic
connectivityand securedaccessto the intemet and
prer"ailing
2. SONSupportprovidesan interfaceto the
parameters
the
to
zuit
these
adjust
for
ease
networls
between
seamlessauthentication
macro
cell SON infrastructurethat ensuresthe two
abiliry
of
and
their
awareness
But
circumstance.
access
embedded
an
It
features
continuity.
service
of
layersworktogether, switching gallsfrom
network
to interworkwith small cellsis still elemenary.
controller which, accordingto the vendor,allows for
cellsas required(suchaswhen the
to
macro
small
issue,
small
of
the
the
other
end
from
Working
scalablenetworksand lower backhaulingcostswith
from
his home network into his car
user
moves
ip'access
manufactuer
and
dweloper
nenrork
cel
to
the
operator's
direct tunnelling from basestations
with no drop-off in service
a
call)
while
making
system
management
network
a
has
launched
product
its
that
adds
Alvarion
core network.
or radio interferencewith surroundingcells.
aimed at the small cell layer of mobile networks
complieswith Hotspot 2.0 and 802.11u (which
3. AgryManagersupportsthe GSlvIAs OneAPI
that allows better communicationsbetweenthe
improvesnetwork discoveryand connection),
'cellular-like'
standardand thereforeenablesdwelopers
open
and
founder
Company
macro
cells.
and
small
experienceover the Wi-Fi
permitting a
to createnew network servicesfor
and
operators
longer
are
no
cells
says
small
Nick
Johnson
CTO
the
user.
from
zero
configuration
nenvorkwith
small cell networls. As the number and densityof
simply standaloneislandsof coveragebutare
small cellsgros's,particularly in city centresand
becomingan integral part of the operator's
shoppingmalls, Johnsonsaysit will be possiblefor
solutions.
and
capacity
coverage
operator to competewith over-the-topplayersand
Syscttt
vorft
Orchattution
is
Net
says
ip.access
replace
areas
fit
into
and
In general,small cellswill
introducelocation-basedservicesthat are not
(NOS)combinesa full suite of tools tbat will
now coveredby macro cells.However,they still
enableoperatorsto quicHy deploy small cells and reliant on the use of battery-hungryGPS data.
requirebackhauland power.Monica Paolini, author
a. AystnCatcherisa remote diagnosticsand
introducenew services.NOS allows operatorsto
of a recentSenzaFili paper on the financial aspects
performance
monitoring tool that captures
performance
and,
cell
improve
small
and
numage
to
the
LTE
of small cells,saysbackhaulis crucial
individual accesspoints and can
from
statistics
data
to
exchange
API,
standard
an
industry
using
costs
backhaul
found
She
case.
business
small-cell
aggregatedataNtft acrossthe small cell layer.It
with the macro network to drive down dropped
for small cellsaccountfor about nvice as much of
can enablenet admin staff to fine-tuneindividuat
call rates,and providebifling information to the
the TCO as they do in macro cell deployments.
small cells,clusters,or the entire layer remotely to
just
provider's
brrsiness
systems.
service
"Baclhaul for small cellsrequiresmore than
perfonnanceor reactto changing
improve
key
management
gives
four
operators
NO,S
Paolini.
"This
says
solutions,"
re-purposingexisting
network conditions.
tools:
is a new market for backfraulvendors- a big
for
"This
isa newmarket
vendors-abig
backhaul
butalsoa big
opportunity
astheyhaveto meeta
challenge
setofrequirements
verydifferent
fromwhattheyareusedto."
is crucialy
Backhaul
COMMUNICATIONS
WIRELESS
AFRICAN
SOUTHERN
coverage. Small cells that combine LTE and Wi-Fi
are easier to install and use less power, and can be
Intqrating backhaul within the small cell enclosure
allows operators to install one piece of equipment
instead of two at the small cell site. According to
deployed precisely where the people are.
However, the density of cell sites means operators
rvill usually have to establish self-healing mesh
Senza Fili's research. This allows them to reduce
their TCO by up to 27 per cent, and Paolini, found
that they could cut their TCO a further 20 per cent
if they allow other operators to share their backhaul.
configurations using self-optimising network
management software to reduce routine network
administration costs. They will also have to address
network and service provisioning.
S m a l cl e l ld e p l o y m e n tws i l l
get bigger
For example, NSN says its iSON (intelligent SelfOptimising Networks) platform essentially provides a
''single pane
of glass" through which to view the
The Global mobile Suppliers Association expects
I4lLTE networlc worldwide to be live this year. At
entire network by consolidating the OSS landscape.
It claims this allows its NetAct application to tune
the networls automatically in response to traffic
fluctuations. The ultimate aim is to save manual
efficrt and improve network availability to optimise
the user experience.
The firm says r.9Ol/also increases the interworking
performance across 3G and LTE by automatically
adapting system linkage parameters such as .lef
the end of 2011, market researcherInforma reported
to the Femto Forum (now the Small Cell Forum, an
industry body set up to promote small cells) that
A Nokia
Siemens
Networks
provides
Flexibasestation
connectivity
via GSM/EDGE,
WCDMA/HSPA+,
andt_TE there were 37 3G femtocell deployments in 23
countries, with 15 more operator commitments. A
(FDD/TDD)
in a zero-footprint
package
thatlends
yein
ago, it estimated that there were more than2.3
itselfto installation
in a variety
of sitesto maximise
coverage
at minimum
million femtocells acrive both privately in homes and
cost.
confgured Circuit SwitchedFallBack, which allows
voice applications to work easily on what's essentially
local calls. It's designed to minimise backhaul (the
largest single operating expense) and core network
a data network. Another application, Mobility RobustnessOptimisation, automaically adapts and speeds-up
upgrades. Quornrs says it also enables small cells to
act as complete mobile networls handling smart
LTE network optimisation and improvement rycles.
IlK-based software house Quortus is taking a
different approach. It recently launched EdgeCentix
voice and data oFload, sessioncreation, switching
and handoff, traffic compression and aggregation,
which allows most core network functions to be
handled at the network edge. This includes switching
and edge caching and presence information for apps.
It adds that all of this is visible to the host operator
macro network.
offices, as well as publicly in metropottan and rural
environments. It forecasts there will be 48 million
small cell accesspoints in use globally by 2014.
There is little doubt that operators need to act. In
many cities, the airwaves are abeady congested - for
instance, the Nigerian communications regulator
recently fined four mobile operators for sub-standard
service due mainly to congestion. Provided data
traffic continues rising as it is, small cells are clearly
the way forward. I
Uniuensal
Base
StationTester
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U'U
FVSS
FREESPECTRUM
ANALYZER
OPTION
Technologiesincludedare AMPS, CDMA lS-gS,CDMA 2000, GSM,
EDGE,GPRS,W-CDMA/HSDPA,WiMax and LTE. lts powerful
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SOUTHERN
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