Post on 07-Mar-2018
INSIGHT REPORT
Small cellS 2012 integration and optimisation
EUROPEMOBILE
REPORT SPONSOR REPORT CONTRIBUTORS
Richard Webb, Infonetics Research
Thomas Wehmeier, Informa Telecoms &Media
Keith Dyer, Mobile Europe
| mobile europe insight report
Keith Dyer: Parker, why do you think the
industry is seeing so much buzz around small
cells right now?
ParKer Moss: The chief reason is the
ramping demand for mobile broadband
capacity. We think 25 times growth in
demand in the next five years is a
conservative estimate in some dense urban
areas and operators all over the world are
faced with an unprecedented need to add
capacity to their networks.
There are only three ways to do that: add
more spectrum, improve the spectral
efficiency of the network, or reuse that
spectrum you have by sectorising the
network. The traditional way to do that is to
split the macro cell, but that's a very
expensive thing to do because macros cost a
lot of money, and sites and permissions are in
short supply.
That's why we think the way to further
densify 3G networks right now is with 3G
metrocells that sit underneath the metro
layer. In 4G lTe networks, metro cells will
bear the bulk of urban data capacity and
need to be built into HetNet coverage and
capacity site plan from the start. metrocells
are a lot less expensive and have a much
smaller footprint, waste less energy by
putting the antenna closer to the user, and
lead to increased spatial efficiency.
Keith Dyer: You mention demand growth
over the next five years. are solutions
available now in the metrocell environment?
ParKer Moss: We announced lightRadio in
February 2011at mobile World congress and
then demonstrated that concept with a live
metro network in Barcelona in 2012, using
the award winning lightRadio cube to
provide a very small, flexible and directional
antenna element for metro cells.. It enables
flexible deployment models with either a
local or remote baseband and is ideally
positioned to deliver very high capacity
with very high energy efficiency and a near
invisible footprint.
We expect metros to be all over the
urban landscape so we put a lot of efforts
into the aesthetics and into reliability: We
worked with Frog Design to get a great
looking metro, and our metro cells are
passively cooled, with no cooling fans,
which significantly improves reliability and
meantime between failure between devices.
Keith Dyer: What are the challenges of
moving to this dense, underlay, metrocell
network?
ParKer Moss: Our insight from trials and
deployments around the world is that the
real cost and complexity of metro is in the
operational layer. In fact we calculate that
80% of the cost and complexity of the
metro layer is unrelated to the radio.
Operators have to rethink the way that
networks are planned, deployed and
maintained in the metro cell world
because new considerations come into
play: access to backhaul and power, site
acquisition, and the deployment and
operation of a much larger number of
network elements than ever had to deal
with. allied to that are new regulatory and
municipal concerns.
Keith Dyer: Do you think operators are
ready to make that shift in planning,
deployment and operation?
ParKer Moss: I think that a lot of
operators have started thinking about
these challenges. The real complexity for
them is that metro cell deployment and
operation draws upon a very wide scope
of skill sets, and it is typically difficult for
an operator, or for a vendor that doesn't
have a full service capability, to optimise
all these new elements at the same time.
To make these decisions you have to
involve the backhaul, site acquisition,
field service and power teams and really
get them to think about the network in a
new way.
metro cells are driving operators to
rethink the orthodox view of network
planning where site locations are optimised
for best possible radio performance, and
instead take a more holistic view of RF,
power, backhaul and site availability.
The good news, that I can announce
exclusively to mobile europe, is that
alcatel-lucent is launching a turnkey
service to aid operators in the planning,
deployment and operation of metrocell
networks. That service leverages our
leading positions in backhaul, wireless and
IP, along with our full service capability to
offer the complete range of skill sets that
operators require.
lightRadio metro cell express will
provide operators with the capability to
respond efficiently and quickly to the
growing demand for mobile broadband
capacity.
SPONSOR'S FOREWORD
RETHINKING SMALL CELL DEPLOYMENT
PARKER MOSS, VICE PRESIDENT, WIRELESS STRATEGY ANDMARKETING, ALCATEL-LUCENT, ANNOUNCES THE LAUNCH OF A NEW
SERVICE THAT WILL SUPPORT OPERATORS IN THEIR DEPLOYMENTOF DENSE SMALL CELL NETWORKS. HE TELLS KEITH DYER HOW
LIGHTRADIO METRO CELL EXPRESS PROVIDES OPERATORS WITH THECAPABILITY TO RESPOND EFFICIENTLY AND QUICKLY TO THE
GROWING DEMAND FOR MOBILE BROADBAND CAPACITY. Parker Moss
mobile europe insight report |
he small cell market is as old as
the mobile industry, and
involves this decade’s big
league of RaN vendors: alcatel-lucent,
ericsson, Huawei, Nokia Siemens
Networks and ZTe, as well as a few small
cell specialists such as airvana, ip.access,
contela and Ubiquisys.
In the mid-nineties, augmenting the
macrocellular network with low power
nodes (e.g., typical output power less
than 4W) such as microcell and picocell
base stations, was considered an option to
increase capacity — for voice coverage —
for GSm and cDma systems.
From the late nineties throughout the
first decade of this century, microcells and
picocells were primarily used as the
anchor of distributed antenna systems
(DaS); again, this was to address voice
coverage issues but deployments were
modest at best, because GSm and cDma
networks were well designed to cope with
large coverage areas.
Until HSPa rollouts took off in 2007, we
hadn’t heard much debate about small
cells. Now, data rather than voice is the
key driver of mobile infrastructure and
with new and better devices such as
smartphones and tablets available every
quarter, mobile operators have to go
deeper in fixing capacity-crunched zones
to support data traffic growth; not only
does data growth put capacity (and
spectrum) at more of a premium, but 3G
signals suffer from attenuation as they go
from outside to in-building much more
than 2G signals do.
all of this has driven renewed interest in
denser cell deployment, and the industry
is expecting widespread utilisation of
various types small cells as a means of
handling the rapidly rising mobile data
volume.
But how much small cell activity is
there right now, and what scale of
deployment should we expect? What are
the challenges to be overcome and what
impact will small cells have on the mobile
network of the future?
MarKet ConfusionThe term 'small cells' seems to mean
many things to many different people and
there is no industry consensus as to the
exact definition. Vendors have been quick
to seize the opportunity to drive new
streams of RaN-based revenues but have
different ideas about the right products,
architectures and terminology. One folk's
'public access femtocell' is another
person's 'indoor pico cell' and someone
else's 'mini-BTS' and so on. So, before we
consider the dynamics of the market, let's
try and clear up some of the confusion
regarding what exactly we mean by 'small
cell.' The chart below is Infonetics' take on
the various flavours of small cell:
T
INSIGHT REPORT
SMALL CELL MARKETREALITY CHECK
BY RICHARD WEBB, DIRECTING ANALYST, INFONETICS RESEARCH
Specifications Microcells Picocells PS Femtocells
Cell radius 2 km maximum 200 meters max 10-100 meters
Output Power 33—36 dBm/2—5 W 250 mW—1 W 1 mW—250 mW
Number of users More than 100 30 to 100 Less than 20
Controller signaling protocol Iub Iub Iub
RRH/RRU option Yes Yes No
DAS usage Yes Yes No
Applications Microcells Picocells PS Femtocells
Low power outdoor sites Yes Yes No
Villages and road sites Yes Yes No
City centers Yes Yes No
Rooftop sites Yes Yes No
Stadiums Yes Yes No
Tunnel sites (e.g., subway) Yes Yes No
In-building sites (e.g., buildings} Yes Yes Yes
Shopping centers, malls Yes Yes Yes
Table 1: Small Cell Specifications Comparison: Microcells, Picocells, and Public Space Femtocells
PiCoCells will Prevail in MaCronetworK DensifiCation
In a picocell, the shorter transmission
distance coupled with lower transmit
power, enhances both capacity as well as
the signal to interference noise ratio
(SINR) achievable within the cell. Put
another way, from a pure radio
architecture standpoint, dividing a large
macrocell into a certain number of small
cells to enable efficient frequency reuse is
one of the most effective ways to increase
the overall system capacity — on top of
advanced signal processing techniques,
expanded use of spectrum, and improved
modulation and coding techniques. While
improving the overall throughput
achievable in the macrocell, this also
brings down deployment costs.
However, dividing a large macrocell
into a certain number of microcells does
not bring enough granularity; a microcell
still requires relatively high power and
covers hundreds of users but from what
we understand from operators, the goal
of cell densification is to provide ad hoc
capacity to areas that typically have less
than a hundred users. In addition, the
new generation of picocells integrates
collapsed RNc and standardized backhaul
interfaces, which also helps the
densification model.
In addition, we are seeing indications
that picocells are likely to have integrated
WiFi. Both technologies have similar range
and power requirements, and this may be
another advantage for picocells over
microcells, as the dense cell option could
have its own in-built offload option e.g.,
alcatel-lucent’s lightRadio now integrates
WiFi; Nokia Siemens Networks' Flexi Zone
and ericsson’s mRBS and pRBS small cell
series integrate Belair’s WiFi features.
PiCoCell-baseD DensifiCationDesign reMains CoMPliCateD
even though there are some benefits to
the pico-orientated small cell architecture,
it is by no means simple to design, deploy
and manage; there are complexities
inherent in small cell networks which are
holding the market back so far. Infonetics
has been discussing these issues over the
past two years with both vendors and
mobile operators and the following
questions pop up the most:
z What is the optimum picocell to
macrocell ratio?
z What is the optimum cell size that
maximizes the picocell throughput?
z Does the receiver configuration matter?
z What happens if the picocell BTS is
within the building or located outside?
z What is the implication of frequency
reuse on the throughput achievable?
z What is the optimum antenna size?
z What are the restraints on small cell
deployment, in terms of size,
appearance, location?
z What are the backhaul options?
no Consensus on sMall CellarChiteCture
When interviewing operators about
small cell strategies, we found more
questions than answers, and little
consensus. Strategies vary widely: some
operators are planning a dense use of
outdoor small cells, especially in urban
areas; others plan only comparatively
moderate use currently, with a few
deployments in urban areas; some have
no plans for outdoor small cells at all,
saying they see no need for the next few
years.
Taking all these perspectives into
account we have established the following
rules of thumb that allowed us to build a
forecast model:
z most operators are planning small cells
only in the urban core in the next three
or so years; some will have none (the
Russian operators), some will have a lot
more (e.g. some of the Nordic
operators).
z Some operators will have none at all due
to their country's regulatory classification
of small cells as potentially carcinogenic
(France, Israel); we do not currently
expect this to become a prevailing
viewpoint but will nonetheless be a
major inhibitor in some places.
z Urban core cell sites are about 5% of
cell sites; each of these urban core sites
will have three to five small cells per
macrocell for most operators we
surveyed; one plans three to eight per
macro, another plans 13-20 (typically
pico cells); several national-scale mobile
operators are planning three to five
microcells per macrocell in dense urban
areas only and none elsewhere.
z asia could have different ratios, due to
widespread RRH usage in china and
Japan, and WiFi hotspots; But Softbank
mobile told Infonetics its next wave of
investment will be in small cells. It will
only start when the TDD lTe macro
network is complete in 2014: 160,000
sites — and with new spectrum.
| mobile europe insight report
INSIGHT REPORT
Though there are some benefits to thepico-orientated small cell architecture, thereare complexities inherent in small cellnetworks which are holding the market back so far.
Table 2: Worldwide Small Cell Units and Revenue
mobile europe insight report |
z Small cells are commonly expected to
be a key characteristic of lTe networks,
yet there is a growing acceptance that
they will also play a vital role in late-
stage HSPa networks, where they have
so far played only a minor role.
z It is unclear how small cells can be fully
embedded in the whole macro network,
because so far, microcells and picocells
have been deployed only to improve
coverage in metro areas and buildings.
z Today, outdoor small cells are deployed
by only a few operators and mostly on a
small scale; therefore, there are few
deployments from which operators can
draw operational data to develop
common practices, common
dimensioning plans, and common
strategies.
So, bearing in mind the inhibitors and
complexity in small cell networks,
Infonetics expects the market to grow
modestly in the short-to-medium term,
with shipment volumes only starting to
ramp up from 2015 onwards; even then,
the scale we foresee (3m units in cY16) is
nothing near as dramatic as other more
bullish projections — admittedly some of
these generated by vendors.
The forecast model we built depicts a
three-phase type of rollout:
z Phase 1: 3G rollouts (2008–2011)
z Phase 2: 3G expansion and upgrades
(2012–2016)
z Phase 3: 4G capacity upgrades
(2013–2016)
Until early lTe adopters start capacity
upgrades, 3G small cells — mostly W-
cDma/HSPa — will be predominant; by
2014, 4G femtocells will become the main
growth engine:
z 2012: 100% of small cells will be 3G
only as we believe early 4G deployments
will only be field trials.
z 2013: Kick-off year for more notable
growth with 37% 4G small cells versus
63% for 3G.
z 2015: Ramp-up with 4G small cells
accounting for 57% of total, overtaking
3G.
rrh/rru, relay, rePeaters, Das anDwifi are also Part of the Mix
The unabated demand for mobile
broadband and the resulting traffic surge
in radio access networks is challenging the
conventional wisdom of just improving
and densifying the macro layer. Put
another way, simply adding new macro
sites and BTS is not enough and no longer
works. But also, the addition of micro,
pico and public access femto small cells,
as discussed above, may not be sufficient
on its own.
There is likely to be a need to also
augment and enhance the existing macro
layer with various low power nodes such
as remote radio heads/units (RRH/RRU),
relays, repeaters, distributed antenna
systems (DaS) and WiFi access points. as
all low power nodes are integrated in the
whole mobile network with the macro
layer, the ensemble creates a
heterogeneous network.
carrier WiFi is seeing a renewed boom,
driven for the most part by mobile
operators eager to leverage the availability
of a 'free' technology (ie. using unlicensed
spectrum) to augment their existing
mobile data services in public spaces;
often, WiFi is already available, but mobile
operators are keen to build out their own
WiFi access points based on newer
versions of the technology: not only will
802.11ac be widely deployed once this
faster protocol is fully ratified, but mobile
operators will also want to integrate WiFi
more closely with the mobile network
using WiFi 2.0 capabilities.
From our discussions with mobile
operators that are strong DaS proponents,
we know that today's active DaS
topologies are bringing enormous
functionality and benefits to the in-
building domain by the shaped and
sculptured RF coverage patterns they
offer, which minimizes spillage and
maximizes in-building signal strength. In
addition, the systems are driven from a
central BTS or NodeB, overcoming
handover issues. also, advanced active
DaS systems are capable of efficiently
extending network coverage far from the
BTS or NodeB, using technologies such as
RF-over-fiber and other transport
mechanisms, which make this an optimal
option to spread an existing cellular signal
in venues such as stadiums, where small
cell solutions are not sufficient to cover
terraces and standing areas.
sMall Cells: not so big just yetIn units, small cell numbers can be big,
and much bigger than those of
macrocells, provided interference and
backhaul issues are under control. But
don’t get too excited. There is no
question that there is a small cell market
and a heterogeneous network market, but
given the magnitude of the annual macro
RaN market, standing at $50B, small cells
are not likely to generate anything too
close to this in terms of new revenues.
also, a clash between the BIG 5 RaN
vendors and the small cell pure-plays that
started with consumer femtocells is
looming. Take for instance the public
space femtocell segment: we currently
count over 20 vendors, more than a third
of which are trying to move upstream and
expand into the picocell segment, which
will lead them to cross paths with the
RaN giants. clearly, it remains to be seen
how sustainable this market is for so many
vendors.
all in all, the small cell market is still
early in the game: the currently available
products are not the ones that will be
purchased by the hundreds of thousands
in several years' time, and a raft of
operational issues persists for operators to
sort out. There are still no widespread
deployments from which the industry can
learn the best practice and form common
strategies, and operators continue to face
challenges regarding the implementation
of QoS, SON and HetNet whilst trying to
build a new-look network from the range
of indoor and outdoor small cells, WiFi
hotpots, DaS and home femtos.
INSIGHT REPORT
| mobile europe insight report
INSIGHT REPORT
WIFI REQUIRES CO-ORDINATIONOPERATOR WIFI STRATEGIES NEED TO BE CO-ORDINATED, TECHNICALLY AND INBUSINESS MODEL TERMS, OR OPERATORS FACE VALUE REDUCTION, SAYSTHOMAS WEHMEIER, PRINCIPAL ANALYST AT INFORMA TELECOMS & MEDIA.
need to open this comment
with a brief confession. ever
since immersing myself in the
topic of Wi-Fi and, more specifically, in
understanding and analysing operator
strategies and business models for Wi-Fi,
I have argued that all operators will
need to integrate Wi-Fi into a holistic
traffic-management strategy focused on
sustainable and profitable mobile data
growth. although I believe we have
clearly explained how Wi-Fi can and
should play a complementary role for
operators, I don’t believe we have
sufficiently outlined the risks and threats
to future operator business models. I
would add, though, that this is not
about scare-mongering but about
presenting a balanced perspective on
future carrier Wi-Fi strategy.
I have spent a large part of the past
year speaking with industry players
(operators, vendors, regulators, OTT
players) about a range of issues related
to both Wi-Fi and the future evolution of
mobile data pricing. These discussions
have brought me to a new set of
conclusions that I am starting
to articulate to our customers. although I
stand by the statement that ensuring
that executives “get” Wi-Fi will be crucial
to the success of operators globally, I feel
that I need to contribute new insights to
the arguments for and against large-scale
public Wi-Fi deployment.
One of the most important
conclusions I have come to is that
although Wi-Fi is indeed going to play an
important role in the development of the
provision of Internet access and other
services, it is not clear that the
widespread deployment of Wi-Fi outside
of the home is going to deliver to
operators the sustainable and profitable
future their shareholders and investors
demand. This is especially true if the
investment in Wi-Fi is not backed up by a
clearly articulated and joined-up strategy
that evaluates the overall impact of a
greater migration of smartphone-, tablet-
or laptop-originated data-traffic share to
Wi-Fi and away from the operators’ core
cellular networks.
One of the principal conclusions I
have made is that many operators are
seemingly “blindly” deploying Wi-Fi
without a clear understanding of the
overall impact of their investments on
their business in the future, especially
regarding the effect on mobile data
usage from their 3G/4G networks.
I
Although I believe we have clearlyexplained how Wi-Fi can and should play acomplementary role for operators, I don’tbelieve we have sufficiently outlined the risksand threats to future operator business models.
mobile europe insight report |
INSIGHT REPORT
I am increasingly of the opinion that
much of today’s operator investment in
public Wi-Fi is led by apparent short-term
thinking about the role that Wi-Fi can
play in alleviating traffic bottlenecks on
their networks. But although Wi-Fi can
obviously play a role in a comprehensive
and holistic traffic-management strategy,
operators are placing too much emphasis
on Wi-Fi without really investing in
demand-side measures (i.e. pricing) that
can enable them to build sustainable and
profitable propositions to increase data
traffic in line with customer demand in a
way that delivers maximum value to the
bottom line. There is still far too much
industry rhetoric around the “challenge”
of data-traffic growth when the reality is
that this level of demand for their service
should be seen as a major opportunity to
monetise huge investments made in 3G
and 4G networks.
The real crux of this discussion should
focus on the fact that mobile network
operators make a lot more money for
every megabyte/gigabyte/terabyte of
data that goes over their cellular
networks (i.e. 3G/4G) than they do
when the traffic goes over Wi-Fi,
especially when it is private, in-the-home
Wi-Fi, where they effectively make zero
revenue. Show me a single operator that
can today claim that it is really
extracting comparable value (i.e.
bottom-line profits) from its customers’
Wi-Fi usage vs. usage on its own cellular
networks.
For some operators that have perhaps
underinvested in their cellular networks,
Wi-Fi has a definite role to play to help
alleviate traffic concerns in certain
locations or at certain times of the day
and because it is the preferred, primary
form of data connection used by many
of their customers. But it’s important
that operators realise the long-term
impact that a strong migration to Wi-Fi
could have on their own opportunities
to make money out of their customers.
The more customers end up using Wi-Fi,
the harder it will be for operators to
persuade them to shell out hard-earned
cash to pay for access to their 3G/4G
networks.
In the short term, the impact is likely
to be that operators that have set up
tiered volume-based pricing will miss out
on “overage” charges when users
exceed their bundled data allowance or
customers deliberately choose to stay on
cheaper plans with smaller data
allowances because Wi-Fi is so freely
available in the home and on the move
that they feel confident enough not to
purchase bigger bundles on more
expensive plans.
In the longer term, the risk is that
there will be a strong migration of
smartphone usage away from cellular
networks and onto Wi-Fi, which would
ultimately dilute operators’ revenue-
generation opportunities from demand
for data access.
I think there’s no question that
customers will still need access to 3G/4G
networks for data connectivity for all
those occasions where Wi-Fi is not
available, the connection is not secure or
the experience is poor. But the real
concern for operators has to be that
these situations are becoming less and
less frequent the more that high-quality,
secure and “free” Wi-Fi is made available
to them.
That being said, I do recognise that
some operators, including O2 UK, have
developed a clearly articulated and
comprehensive view of the role that Wi-
Fi can play in expanding their other new
business lines (O2 media, O2 Wallet, O2
money, Priority moments, etc.) and as a
result have a much clearer and stronger
strategy to underpin their investments in
Wi-Fi rollouts without fearing revenue
“cannibalisation.” I also recognise that in
some specific scenarios, such as data
roaming, Wi-Fi could actually generate
incremental revenues that have not
successfully been captured on cellular
networks because of exorbitant data-
roaming prices.
But I don’t think the rest of the
industry has caught up with the leading
thinkers in this space. We believe more
operators will need to follow O2 UK’s
lead if they are going down the path of
investment in Wi-Fi. This means building
a business case from the bottom up that
covers all areas of Wi-Fi that have an
impact on the operator business and is
not simply focused on isolated aspects of
the Wi-Fi value proposition, such as
network-capex alleviation. We also think
operators will have to develop much
better insights into the future impact of
major Wi-Fi adoption and usage on the
profitability of their own (cellular)
mobile data businesses.
I do recognise that someoperators, including O2 UK,have developed a clearlyarticulated and comprehensiveview of the role that Wi-Fi canplay in expanding their othernew business lines.
Home and enterprise (below left): carrier WiFi may threaten the businesscase of mobile operators if not thought through, warns Wehmeier.
A TECHNOLOGY WHOSE TIME HAS COMEJim Tavares is a Director for Strategy & Business Development in Cisco Services. Keith Dyer
| Mobile Europe
Caption CaptionCaption
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ADVERTORIAL
It is not news that mobile data is growing at an
unprecedented rate and will continue to do so in the near
future. Alcatel-Lucent Bell Labs predicts that mobile data
will increase twenty-five times by 2016. It is also not news
that a macro-only approach cannot provide the capacity
needed to satisfy the demand. Recently, it has become
widely accepted that the solution for providing massive
capacity is the densification of the network with metro cells,
in essence creating a heterogeneous network or HetNet.
Metro cells are appealing to operators for a number of
reasons. They are cost efficient and may be quickly placed
just about anywhere where coverage and capacity is
needed. Additionally, metro cells are spectrally efficient,
enabling operators to squeeze more capacity from their
scarce spectrum than by using macro cells alone.
However, what will be news to some is that large
deployments of metro cells pose a number of challenges
that require operators to rethink their operational and, in
some cases, business models.
CELL LOCATIONOptimised placement of metro cells necessitates the
development and use of new models, tools, and
methodologies. Unlike macros, metro cells provide
coverage and capacity to much smaller areas or hotspots
within the larger macro network. A hotspot usually ranges
from 70 to 100 metres in diameter and occupies only
about eight percent of a typical macro cell’s coverage area.
Because of this, the established models and tools used in
the planning and design of macro networks are not
effective in determining where to place metro cells. Not
only are they inaccurate for small areas, but they also do
not consider other factors important in placing metro cells.
The first step in determining where to place metro cells is
to pinpoint the exact location of the hotspots. This can be
accomplished by creating a heat map. The process involves
collecting subscriber call records over a period of time, geo-
locating the calls on a map and then extracting the packet
data volumes to determine the amount of data being used
by location.
Using the heat map, the operator can then identify the
macro cells that are the best candidates for offloading. For
each of these cells, the operator must determine the
number of metro cells, along with their placement within
the macro’s coverage sphere, needed for optimal
offloading. This requires several calculations for each of the
macro offload candidates. The
offload potential is, however, not
the only factor that is important
to the selection of the metro cell
sites. To ensure easy
deployments and low site
rentals, the MSP must also
consider shared carrier exclusion
zones when applicable, friendly
landlord sites, as well as sites
offering power and backhaul.
SITE ACQUISITION Operators know how to
acquire sites for macro cells,
from locating the best sites
within search rings, to
negotiating site rental leases and
management agreements. Many
operators also have long-
standing relationships with
tower companies. Metro cells,
however, are not placed on towers or rooftops, but rather
in new locations, such as lampposts, utility poles, and on
the interior and exterior walls of buildings. Another
difference is that metro cells are deployed in mass,
requiring the acquisition of many sites all at once.
To deploy metro cells quickly and keep costs low, the
MSP has to find many suitable sites with low rental fees,
readily available power, and access to backhaul. Forming
GUARANTEE A SUCCESSFUL METRO CELL DEPLOYMENT
Metro cells present operators with a number of deployment challenges that must be addressedbefore their full benefits may be realised. That means operators must not only rethink how theyplan, design and implement their networks, but also their business relationships andpartnerships, says James Seymour, Senior Director of RAN Strategy, Alcatel-Lucent.
Adoption barriers to the
deployment of metro cells.
Ease of installation and
turn up will be critical in
metrocell deployments.
Mobile Europe |
ADVERTORIAL
strategic relationships or partnerships with municipalities,
utilities and other companies that own or have access to
infrastructure suitable for the deployment of metro cells
offers an effective means of doing this. Municipalities own
lampposts, traffic lights, and other structures. Utilities
possess thousands of power poles and wireline service
providers have telephone poles as well as other
infrastructure, such as Digital Subscriber Line (DSL) and
Gigabit Passive Optical Network (GPON) that not only offer
a place to mount metro cells, but also easy access to
backhaul. There are also cable companies with miles of
above the ground cable strands and companies with
thousands of Wi-Fi locations that can provide mounting
locations for metro cells and the necessary power and
backhaul.
By forming strategic relationships and partnerships,
operators can negotiate right-to-use agreements with
municipalities and companies that have infrastructure
within those targeted locations. This facilitates the
availability of highly suitable sites when metro cells need to
be deployed. Additionally, by negotiating right-to-use
agreements for many sites at one time, the MSP is able to
keep rental fees for individual sites low.
THE RIGHT BACKHAULMetro cell backhaul demands a number of questions of
operators. Does the backhaul network have to provide the
same level of performance for metro cells as it does for
macro cells? What other factors must be taken into
consideration to ensure the quick and cost-effective
deployment of metro cells? What is the best way to keep
the operational costs of the backhaul network low? Does
the selection of metro cell sites have any impact on the
backhaul network?
First, the design of the metro cell backhaul network must
deliver the appropriate level performance. Will metro cells
primarily be used for filling in coverage holes or for
offloading capacity? The answer to this question
determines the level of performance that needs to be
supported. Coverage requires that the metro cell backhaul
network meets the sa me level of reliability, availability, and
quality of service (QoS) as that provided by the macro
backhaul network. Basic capacity offload, on the other
hand, has performance requirements that are more
relaxed. Metro cells used for coverage will typically require
a higher performing, higher cost backhaul network than
that needed for capacity offload.
It is also essential that the backhaul network be designed
for easy scalability and maintainability as well as for the
easy installation and turn up of metro cells. Building in
scalability ensures that the backhaul network can grow
quickly and cost-effectively to keep pace with the
deployment of metro cells, while designing in
maintainability reduces the number of required site visits,
keeping operational costs low. Designing the backhaul
network for the simplified installation and turn up of metro
cells also guarantees quick deployments and fast time to
market.
The selection of certain sites for the deployment of
metro cells may adversely impact the cost of
backhaul. Some sites may offer optimal locations of
coverage and capacity, friendly landlords, low rental
costs, available power, and easy accessibility for
installation and maintenance. However, if these sites
do not have readily accessible wireline backhaul or a
clear line of sight (LOS) back to a backhaul
aggregation point, then the cost of providing
backhaul may be too high, outweighing the other
advantages these sites have to offer.
This combination of backhaul availability and site
performance means that to keep backhaul costs as low
as possible, operators must do the backhaul and metro
cell radio design at the same time to ensure a selection
of sites that optimizes backhaul costs.
CONCLUSIONTo realise the full benefits of metro cell deployments,
operators must rethink their approaches to site
acquisition, RF planning and backhaul to take account of
the greatly increased need for scale, flexibility and low
operational cost. Only by treating the deployment of
metro cells in a holistic, whole-life manner, can operators
fully unlock the business benefits of metro cells.
More InformationTo learn how Alcatel-Lucent’s lightRadio™ Metro Cell
Express comprehensive solution can help you guarantee
the successful deployment of metro cells, please visit
www.alcatel-lucent.com/lightradio-metro-cell-express/.
ABOUT THEAUTHOR:James P. Seymour isSenior Director ofRAN Strategy in theWireless CTOorganisation, Alcatel-Lucent. He is therecipient of a BellLabs Fellowshipaward for hisoutstandingcontributions towireless technologyand first joined AT&TBell Laboratories in1994.
Optimal site acquisition
requires a rich ecosystem
of partnerships and
relationships.
mobile europe insight report |
INSIGHT REPORT
SON & MANAGED INTERFERENCETe is predicted by many to bring
with it the advance of the true
Het Net, as operators deploy
small cells that are intended to relieve
capacity-stressed sites in zones across dense
urban areas, at lower costs than by rolling
out an equivalent macro cell expansion.
But the challenge of integrating a small
cell layer into the macro layer brings with it
a major concern for mobile operators —
that of interference management.
compared to traditional single macro
layer networks, small cell devices will be
deployed in very high numbers. even if it is
at just three cells per macro cell (and many
people think it will be many more), across
just a fifth of the network, that would be
an additional 12,000 cells in a network like
Vodafone’s in the UK. If they were to be
deployed in an uncoordinated way, this
would present significant challenges
around interference management and
mobility management (how devices are
attached to, and moved between, network
layers).
Interference is a particularly difficult
conundrum to be solved, explaining its
continued presence, along with backhaul,
as one of the key deployment challenges in
the small cell model. This includes
interference between both the macrocell
layer and the small cell layer, as well as
interference between the small cells
themselves, between neighouring pico
cells. In fact, this topic is as relevant in 3G
as in lTe networks, and brings with it
many similar concerns.
at the lTe World Summit, held in may
2012, Jaime lluch, Radio access
Technology manager, Telefonica,
confirmed that interference issues are still a
current concern for operators. Outlining a
situation where an operator is considering
deploying a small cell layer within an
existing network, he highlighted the fact
that differing vendors still have differing
opinions on whether he can technically
deploy in a multi-vendor manner, or stick
with his existing vendor.
For example, you can read an ericsson
interview within this report in which the
company states quite clearly that if
operators want to benefit from small cell
deployments, they must use cells from the
same supplier as the macro vendor. Yet, of
course, that’s not the story new entrants
tell, or even competing “incumbents” such
as NSN and alcatel-lucent.
alcatel-lucent’s view is that by handling
hand-off between the macro and micro
layers on the S1 interface, operators will
achieve a satisfactory level of performance.
That means that operators don’t have to
wait to deploy hand-off on the X2
interface. NSN insists its Flexi Zone
architecture, which sees clusters of small
cells managed in an aggregated manner
by a local controller node, can be deployed
in a non-NSN macro cell and still have
beneficial effects on the overall capacity of
the macro.
competing messages can create
confusion. “When I ask the incumbent
vendors if interoperability can happen, they
say it can't be done. If I ask the new
entrants, they say it's not a problem…”
lluch said, indicating that the industry itself
is not necessarily helping with the clearest
possible view of how interference can be
mitigated.
another operator we spoke to said that
there is still a lot of due diligence to do on
interference on small cells interference
planning, even though the macro
environment is well understood.
The industry, of course, does have tools
at its disposal to meet the demands of
handing mobility and interference issues
between cells operating at differing power
levels and layers in the network.
The Small cell Forum claims in a recent
white paper, “W-cDma Open access Small
cells: architecture, Requirements and
Dependencies”, that interference
management techniques allow small cells
and macrocells to coexist in the same
frequencies without causing undue
interference.
You can derive a very good idea of how
the “small cell industry” itself recommends
operators deal with the issues of
interference, from an article written by
Simon Saunders, chair of the Small cell
Forum, in may 2012 for industry blog
Wilson Street (funded by alcatel lucent for
the discussion of small cell matters).
Saunders argues that interference “sounds
bad” but “can actually be a good thing”.
His take on the interference issue is that,
managed carefully, the use of controlled
interference could improve mobile network
performance 100 fold.
He outlined a few of the likely causes of
interference between small cells and the
macro layer, tests that the Small cell Forum
L
mobile europe insight report |
INSIGHT REPORT
carried out, and steps that can be taken to
mitigate that. Saunders wrote (all extracts
reproduced with permission of the Small Cell
Forum and Wilson Street) that the Forum
has spent a lot of time looking at the
potential impact of interference and how
to mitigate it. Its testing has included the
following scenarios:
z co-channel deployments where the small
cell and macro are on exactly the same
frequency
z closed access nodes and what happens
when a mobile user, who is not registered
for that small cell, gets close to it and
generates and receives interference
z low frequency bands where signals go
further
z and small cells and interference in lTe as
well as 3G.
“When small cells and macrocells are on
exactly the same frequency (co-channel)
there are some areas of interference
between the macrocell and the small cell,”
Saunders says. “This happens because
transmit power is turned up when a
handset is at the furthest distance from a
cell, and because a handset might hear a
small cell better than a macrocell but not
be registered to use it. In our studies on
interference, we looked at three scenarios
for interference:
z a macro-connected handset that is in
close proximity to a small cell that it is
not registered to use, causing a
deadzone.
z a small cell-connected handset that is at
the furthest range of the small cell.
z a small cell-connected handset that is
closer to a small cell in the house next
door, but is not registered to use it.
“clearly we’re most concerned with how
a small cell interferes with a macro network
because it can impact the most users.
“These are all worst case scenarios. If
you were able to arrange your small cells
on a slightly different frequency or
straddling two macrocell channels, you get
zero or much-reduced interference. also, if
you only had open small cells, it would also
be avoided because the handset would
roam between the strongest signals.
“But many operators will need to deal
with a co-channel interference caused by
open and closed cells. Some have a hybrid
model where closed small cells are opened
up to unregistered users if they are
experiencing or causing a lot of
interference to the neighboring macrocell.
“So even before we go into complicated
interference management techniques,
there is a host of ways of obviating
interference.
1) You get dead zones because there is too
much small cell power in relation to
macrocell power. If the small cell was
aware of that the neighbouring
macrocell had a weak signal, the small
cell would scale back its own power.
2) If a small cell-connected device is very
powerful and drowning out a macrocell
in close proximity, we recommend that
the small cell has the ability to tell the
handset what the maximum power it
can transmit at so as not to impact the
neighboring macro and to adjust its
own sensitivity to avoid its own receiver
being ‘deafened’ by the strong signal.
3) If a macrocell is interfering with a small
cell, unfortunately you can’t really
tamper with the macrocell output. It has
been manually configured to give a
certain coverage level and you don’t
want to change that every time a new
femto is turned on. But the small cell
can adjust its power to give the
optimum balance between good
coverage over its designated area and
interference beyond its reach.”
interferenCe Can be a gooD thingFinally, Saunders concluded that those
worried about small cell interference need
to consider the opposite scenario where
there are no femtocells at all.
“The average 3G throughput in a
metropolitan district (and these are the
results of a real test) is just 50kbps.
Interference impacts so much that there is
less that 1mbps of shared capacity in the
entire macrocell.
“If you introduce femtocells into this
area, macrocell performance improves
substantially. average user throughput
jumps to 8 mbps each, while the shared
capacity increases to 88 mbps – 100 times
greater than when there is managed
interference.”
Saunders’ summary: to get 100x
throughput compared to macro-only
networks, the following techniques may be
applied:
z adaptive Pilot Power control
z extended Tests for Dynamic Range
z Uplink power capping
z Dynamic receiver gain management.
the sonas well as taking these kinds of steps, the
hope of the industry has been that Self
Organising and Self Optimising Networks
would enable operators to achieve lower
costs of deployment and operation by
automating many processes that are
currently labour-intensive, and also deal in
a dynamic fashion with some of the
interference and mobility management
issues that the Het Net could introduce.
at one level, well-understood by
operators, SON can be about auto-
configuration, where an eNodeB can
autofeed to and from a configuration
server, download its configuration, and in
future carry out aNR (automatic
Neighbour Relations) on X2 interfaces.
“That’s about as far as SON goes today,”
one operator told us.
“There’s a lot more we could see. I think
in terms of the self optimising part of SON,
generally operators are a bit sceptical at
the moment as to how much you let this
run. They are happy with auto
configuration, but there are so many
parameters to adjust, and dynamics, that it
takes fairly large optimisaiton teams do this
work. clearly there will be financial benefts
if you can then automate this but that’s
not there at the moment. For operators it’s
‘steady as she goes’.”
If you’re wondering what exactly is
meant by SON, the following specfications
are a useful primer.
Firstly, SON is about the automatic
collection of data from nearby and
neighbour cells. each small cell gathers
data from neighboring cells through a
combination of:
z measurement reports generated by
the mobile users, which include a list
of their serving cell’s neighboring cells;
z Network monitoring mode detection
of downlink signals from neighboring
cells, which is performed by small cells
that behave as simple user equipment
(Ue) devices.
z exchange of information directly
between cells.
This last point brings us back to the
discussion about which interfaces to do this
upon, as the industry is waiting for the X2
interface to enable cell to cell
communication. (That is why a vendor
such as alcatel-lucent argues that handoff
on the S1 interface is sufficient, for now)
after the Organising, comes the
Optimising part. Once data has been
collected, parameters are then inputted
either in a centralised server that then
optimises a group of small cells, or it can
be done in a distributed way, whereby
each small cell optimises along its own
parameters.
The hope the small cell industry has is
that SON technology will unlock some of
the business case for HetNets. The
challenge though, is matching existing
SON architectures, which tend to be
centrally implemented, and limited in
scope (configuration, rather than
optimisation) to the need for SON software
that can act in a more distributed manner,
to enable the deployment of interoperable,
multi-vendor networks. That requires what
is termed a hybrid approach, blending
centralised SON coordination with more
distributed models.
Due to its promise of reduced cost,
increased automation, and increased
distributed intelligence, SON technology is
seen by many as key to the success of small
cells. even in dedicated-carrier residential
femtocell deployments, where cells are
behind walls and very low powered
indeed, small cells must have plug-and-
play simplicity, and they must be capable
of automatically adapting their parameters
depending on conditions. In outdoor
environments, where output higher may
well be higher, SON will be even more
crtitical.
Some small cell vendors are hoping that
their existing knowledge of SON, gained
through the deployment on femtocells so
far, can be integrated with operators’
existing centralised SON systems, to allow
an overall management capability across
the macro and small cell layers.
at the moment, as we have seen, the
centralised SON servers are not designed
to receive parameters, either manually or
automatically from a separate layer of a
large numbers of small cells. This could
lead to a class of SON that ties the
experience gained through the
management systems of femtocells to the
macro layer management systems.
If this works, it would give small cell
entrants, regarded as standalone solutions
providers, the ability to present themselves
as being able to be deployed in an end to
end fashion in the network. It is another
brick removed from the wall that
incumbent vendors are building out of
coordinated mobility management,
interference management, and SON.
Finally, it should be noted that SON and
interference management specifications
change with the industry srtandards. as the
industry moves to lTe Release10 and
beyond, 3GPP is exploring new
technologies that would incorporate more
sophisticated interference management
techniques into operator networks,
techniques such as Range expansion, and
eIcIc (enhanced Inter cell Interference
coordination). Range expansion is the term
given to a technique that would allow a
user on a capacity-constrained cell to
connect to a nearby small cell, even if it is
at lower power than the macro cell. This
relies on advanced receivers that can
operate at lower signal to noise ratios.
For those who can wait, these are issues
that can be sorted in time. But for those
who must deploy now to meet demand,
the situation is still unclear.
| mobile europe insight report
INSIGHT REPORT
Capacity/Mbps
Femto + macro Macro-only
Expected available throughput per UE 7.87 0.08
Number of UEs per cell (34 UEs across three macro cells) 11.3 11.3
Expected available throughput per macro cell (= network capacity) 88.9 0.9
Increasing the available throuput with the use of femto plus macro cells (Small Cell Forum).
Mobile Europe Insight Report |
INSIGHT REPORT ROUND TABLE
THE PARTICIPANTS
An exclusive Mobile Europe debate
Held in association with Avren Events, organiser of theSmall Cells World Summit
SMALL CELLSthe network ofthe future
JULIAN BRIGHTSenior Analyst,
Networks, InformaTelecoms & Media
KEITH DYEREditor,
Mobile Europe
RICHARD WEBBDirecting Analyst,Infonetics Research
VIRAJ ABHAYAWARDHANASpecialist Strategy, BT Wholesale
ALEJANDRO PINEROSmall Cells Director,Avren Events
ANDY SUTTONPrincipal NetworkArchitect, EverythingEverywhere
MATT YARDLEYPartner,
Analysys Mason
| Mobile Europe Insight Report
INTRODUCTIONSKeith Dyer:
Let’s have a traditional start – cards on
the table. What’s your current
involvement with small cells?
Andy Sutton: I work in the area of RAN architecture
evolution and mobile backhaul and I’m
responsible for a rolling five year evolution
plan for the network, looking at the
evolution of the RAN and at how it will
impact backhaul requirements. The small
cell area is an interesting challenge in
itself; we need to find a new economic
price point for small cells, generally one
tenth the price of macro cells, and that
impacts the overall budget for acquisition,
the infrastrucure itself and backhaul. I’m
also heavily involved in the NGMN
Alliance work on small cells and on small
cell backhaul.
Julian Bright:The InformaTM networks team focuses
on all aspects of network technology, so
we encompass RAN, all aspects of small
cell technology and produce various
forecasts, research and analysis.
Alejandor Pinero:At Avren the portfolio I run works with
the Small Cell Forum to deliver a series of
small cell events around the world. I am
in ongoing conversation with vendors,
analysts and operators to come up with
events that are attractive to everyone.
Matt Yardley:I'm working with operators to
understand external business cases in
fixed and mobile, and with other
stakeholders who are becoming
increasingly interested in the space.
Governments are pushing to get
ubiquitous coverage at high speed, and
that’s deriving a lot of interest. For me,
understanding how fixed and wireless will
work together in the future is really
interesting.
Viraj Abhayawardhana:At BT Wholesale we have worked on
strategy around small cells for a number
of years, in terms of innovation and
research. I also chair the Backhaul SIG in
the Small Cell Forum.
BT is rolling out a lot of fibre,
particularly in urban areas, so my role is to
ensure that infrastructure can be used for
the backhaul of carriers’ small cells. We’ve
also done a lot on wireless cities, so have
gone through the pain of deploying the
WiFi flavour of small cells in a number of
cities.
Richard Webb: I focus on a number of different
wireless markets, macro and small cell and
mobile architecture. We include micro,
pico and all flavours of small cells in the
public network and consumer space.
We’re also looking at carrier WiFi and the
impact of RAN base architecture
development, to look at the whole piece
of mobile operator CAPEX to try and
figure out the options for different
strategic deployments and the choices
the operators are faced with at the
moment.
INSIGHT REPORT
SMALL CELLSbig debate
Mobile Europe brought together operators and analysts to discuss the directionsoperators and carriers are taking to plan, deploy and support small cells. Thediscussion roamed over the rationale for small cells, how and when operatorswill deploy, the backhaul challenge, and how WiFi fits in.
Mobile Europe Insight Report |
SMALL CELLS NOWKeith Dyer:
Where are we now with operator
deployments of small cells?
Richard Webb: It would be hard to point to a very
strong example of an operator
pioneering in Europe with a widespread
small cell deployment. Operators require
a long runway to explore this technology
and still have a lot of concerns around
interference and how small cell networks
play with the macro network. There are
also cost-related or model issues related
to the small cell form factor, and real
challenges in terms of scaling this up.
So there is a set of technical changes
to overcome, and after that some
commercial challenges as well. That
means we are seeing a very low, modest
market in terms of actual shipments for
RAN infrastructure vendors. They’d all
like it to be a much bigger market and
many of them are counting on that.
Julian Bright:The consumer femtocell market has
been quite fragmented: we’ve seen
quite successful adoption of the
technology by some operators, whilst
others have elected not to go down
that route. But overall that market has
not developed as quickly or seen as
broad an uptake as anticipated 18
months ago.
Our expectations are that we will see
growth in small cell, but that requires
definitions. In pico cells there are
deployments. If you look to new sectors
like metro cells, operating like a shrunk
down micro cell or a single sector
macro cell, currently that’s very much
in the early phase of moving into trials
with operators and vendors. There’s still
a lot to prove in terms of the
technology. From the vendor side the
major vendors are pinning a lot on the
uptake of small cells. There is a
reasonably compelling case to move in
this direction but we still need to see
operators convinced that the
technology works, that they can
backhaul it effectively... so there's that
learning phase before moving to any
significant deployment.
Andy Sutton: Everything Everywhere is in the fairly
unique situation of currently integrating
two large macrocellar networks. We
started with a combined site base of
27,000 T-Mobile and Orange sites, but
we’re cutting that down to around
18,000. Although the new network will be
a lot larger than either previous network
was, we are still looking at some capacity
issues. Given the site base we have to
start with we've done a lot of work
looking at what level of densification we
will require and at what point it becomes
cost effective to start targeting specific
traffic hotspots.
There's a lot of capacity in the macro
network still but there's only so far you
can go in terms of some practical aspects:
how much spectrum you have, the
constraints on how much power you can
emit from a cell site, and how densely
packed a macro grid can become in terms
of managing interference and the user
experience. So we are starting to see
some practical constraints in the macro
network, however there’s still some
additional densification that can be
realised if we have to.
What we need now is the most cost
effective way of addressing capacity. And
actually that capacity often comes from
fairly small hotspot areas or hot zones.
Getting the capacity where it's required
and removing that traffic at source will
reduce overall interference in the macro
network to produce capacity gains in the
macro space. It should also give you a
lower cost point, which is where I came
up with this figure that we really shouldn’t
be paying any more than a 10th of the
price of a macro cell for a small cell on a
like for like basis.
So it is still something to come in the
main. We have small cells deployed in
special projects at the moment, in-
building etc. Operator owned, operator
backhauled public access pico cells—
these kind of cells are just starting to be
realised now and we are seeing products
come to market. We have plans to roll out
LTE: our LTE capacity will be delivered by
the macro network initially, and as that
becomes constrained we are looking at
small cells some way down the road for
LTE. The real driver at the moment is 3G
small cells. We are now starting to see a
real requirement for 3G small cells with
features such as HSPA+ Dual Carrier
operation and 64QAM, so there is a
significant amount of capacity with
20MBps backhaul requirement downlink
and 5Mbps, initially, on the uplink.
ROUND TABLE
Left: The panelassemble at The RoyalExchange, London.
| Mobile Europe Insight Report
INSIGHT REPORT
????????
Alejandro Pinero:I think we are seeing operators
building up a portfolio of solutions. We
will talk about WiFi, and I know that in
the USA there’s widespread use of DAS,
for sporting venues for example. It’s
worth considering that as well, within
the overall small cell discussion.
SMALL CELL REQUIREMENTSKeith Dyer:
Can we size the likely scale of small cell
deployments, so we could understand
what requirements small cell deployments
might place on the wider network?
Richard Webb:There’s quite a range in terms of scale.
Three to six per cell is typical, but we’ve
heard operators say they will only add
small cells to 20% of macro sites where
they might be looking at somewhere like
to 5-10 added incrementally over time.
I’ve even heard 20 to a macro cell, which
seems a bit of a stretch to the model.
Andy Sutton:Today we would consider deploying a
single small cell to a hotspot to relieve
capacity, clearly over time that would
grow. Our thinking is somewhere in the
region of three to six small cells per
macro. I hear people say up to 10, and
people often think that maybe ten would
replicate the coverage of a macrocell. I
think it is impossible to replicate the
coverage of a macrocell with small cells;
they are fundamentally different and you
have to plan accordingly. One of the
things we are trying to understand from
our trials is even though we’ve got the
coverage we require, what additional
coverage does a small cell bring? When
you put small cells down at street level,
you’re going to get 10 yards into the back
of a restaurant or shop, where you often
lose that macro cell coverage. So in that
environment you get additional coverage
that was certainly not the primary
objective for small cells. But if we
introduce additional coverage and our
subscriber sees coverage on his handset
he’ll want to make a voice call as well as a
data session so therefore we end up
supporting voice and data…
Viraj Abhayawardhana:What I'm hearing from the Small Cells
Forum SIG for backhaul is that for small
cells to work there are two key challenges.
One is sites, and the other is backhaul.
How do you obtain these sites in a
painless way and then manage the sites.
Andy is saying 18,000 macro cells but if
he deploys small cells at scale it will be an
order of magnitude bigger than that, so
how do you manage this kind of site
portfolio? That’s one of the key problems.
The second is that backhaul is a significant
portion of cost: if you want to bring that
down to 1/10th how do you get that cost
per site down to a level that can work? As
a backhaul provider we don't care what
goes on the end of it but we like to
understand what performance that will
place on the backhaul products that we
like to provide. So the key issue is about
how reliable should small cells be? Do you
see these having as 99.999% reliabilitity
or something lower than that, because
that drives the cost.
Where are the compromise that need
to be made in an economic sense? Will an
operator be willing to carry voice as well
as data? Could you carry the voice on the
macro cell and only carry data on the
small cell — is that possible because again
that drives a different requirement on
timing and the availability of timing. I
think operators are going through trials,
and the trials are meant to understand
these scopes and where these
compromises can be made and what kind
of use cases can be made, the services
you can delver effectively over small cells.
So that’s really a crucial juncture for me. I
personally think if there’s no economic or
cost-effective way of doing this it won’t
happen at the scale we want it to happen.
Matt Yardley:If the sites and backhaul are the two
fundamental restraints, which I think
they are, then you look at FT in Europe
and KDDI in Japan, who are both doing
indoor WiFi based strategies. Is that
because sites and backhaul externally are
more complicated? Or is it that they are
making that choice because it's the lower
hanging fruit and they might be trading
off to some extent the quality part? It
seems to me at the moment there's more
of a momentum towards WiFi and it is
probably for the very simple reason that
the installed base is there and the
economics are so good.
It doesn't mean it's going to win out in
the end but that seems to be where the
experimentation is. Now when you got
to an external small-cell based approach
the interesting question is to what extent
that addresses the in-home demand. I
think that’s the really interesting switch
point because it may be in the long term
Mobile Europe Insight Report |
ROUND TABLE
that the WiFi thing switches over to
external, but at the moment it's really
hard to call.
Richard Webb: I think in the long term there will be a
very compelling case for both, but I agree
that WiFi has been an available
technology that operators and users are
comfortable with. Right now it’s about
getting a proportion of traffic off the
network to ease data congestion. In time
we will see WiFi integrated into small cells
and see dual infrastructure, as there are
very compelling reasons to have both. For
example WiFi does not handle video
streaming as well as LTE networks that are
more applicable to that kind of content.
And then there’s the ability to have data
sessions simultaneously on the same
device, with a video stream on LTE and
files over WiFi at the same time, to give a
dual WiFi-LTE experience.
Matt Yardley:Standardisation will come around the
things that WiFi does well, and that small
cells do well. We hear about WiFi not
being able to deal with encryption,
authentication, policy control, and if that
were resolved would you see a femto and
WiFi strategy start to become more
common in the next five years?
Andy Sutton: Even if we have carrier grade WiFi,
again what does that mean for backhaul?
If we want low latency in our macrocell
network, then surely we want to match
that user experience.
Richard Webb: Yet one of the things I’m hearing from
the vendors now is kind of the reverse of
what Andy was saying, that there is less
focus on making WiFi carrier grade and
more focus on making small cells more
WiFi grade, more best-effort rather than
the macro model of due diligence that
operators would put towards the
deployment of a macro cell. Just
proliferate small cells, throw them out
there, with the mindset that 20% would
be exactly where you want them, 60%
more or less where you want, and maybe
20% won’t really do a great deal in terms
of benefitting that area, but the overall
benefit in terms of cost and speed of
deployment is there. So they are trying to
put the smarts into the small cells to allow
operators to just throw them out, almost,
wherever they have a specific set of
challenges, without necessarily the same
analytics and criteria that you would get
for macro cell sites. So I think we might
see a little bit more of that, and that
impacts on backhaul, and that’s why I
think we’re seeing things like unlicensed
millimetre wave radio get consideration,
which is something that would never have
been on the table for macro. There seems
to be a gradually lowering set of
parameters in terms of the reliability of
that backhaul, a gradual shift of
philosophy in deployment of small cells
being driven by the vendors.
Andy Sutton: It’s potentially a huge gamble and
you’d certainly have to see the acquisition
and backhaul price low enough to justify
doing that, and also in the future the likes
of eICIC and more advanced features like
CoMP find their way down into the small
cell layer, we’re not really seeing that at
the moment. Those are advanced features
that require very tight company between
the small cell layer and macro network in
terms of coordination and radio resource
management.
This really leads into a discussion of
what the small cell architecture will look
like. Is a small cell with traditional
backhaul a long term solution, or actually
if you want to build a small cell layer
should it be subtended from the macro
layer which then changes the dynamics of
those coordination issues, but again
you’ve still got the acquisition issues and
need to get fibre out there. To my mind
that’s more of a Het Net discussion, an
advanced discussion for the future, than
where we are today with small cells.
OPERATIONAL CHALLENGEKeith Dyer:
I wonder what challenges small cells
will place on the way operators install and
manage the network? Their network
teams are geared for macro installations
up towers, for instance, rather than a
single person on a ladder.
Julian Bright:Vendors do seem to be putting a lot of
effort into that element of the small cell
offering, so that installation is a very
simple process. It all sounds good in
theory and if it works that well in practice
then it will ease the process considerably.
Richard Webb:Some operators are saying they see a two-
man team for micro cells installing two to
three of those sites per day. For small cells
a one man team would be deploying
four to six in a day. What’s interesting is
that this is a metric that has not really
been a part of their macro thinking.
Matt Yardley:Looking at it from a radio perspective, in
small cells the traffic is where the traffic is,
you’re not necessarily going to have the
flexibility to say, “Stick the site 200m
down the road, and we’ll change the
parameters of the grid to adapt.”
Viraj Abhayawardhana:The devil is in detail on sites. I think it will
all come down to those three to six sites
per macro, then working out where you
want to go. Then the backhaul portfolio
should be wide enough to select these
different options. There’s not going to be
one solution for all.