The paper seeks to establish a fair analysis of various broadband delivery mechanisms and how they stack up vis-à-vis Fiber. The paper discusses the growth of data consumption over the years and the forecast for upcoming years.
Abstract
The paper seeks to establish a fair analysis of various
broadband delivery mechanisms and how they stack up
vis-à-vis Fiber. The paper discusses the growth of data
consumption over the years and the forecast for
upcoming years. Further the paper elucidates various
promising technologies like Fiber, WiFi, Whitenoise,
Microwave etc that are being used for backhaul to
deliver the broadband to the masses. It ends with a fair
comparison of various technologies and provides
recommendations. The intended audience are Technical
Managers, Technical Committee Members, Account
Managers, Solution Architects, Project Team etc.
Introduction
In a hierarchical telecommunications network the
backhaul portion of the network comprises the
intermediate links between the core network, or
backbone network and the small sub-networks at the
"edge" of the entire hierarchical network. Backhaul
technologies include:
Wireless:
- Point-to-point microwave radio relay
transmission (terrestrial or, in some cases, by
satellite)
- Point-to-multipoint microwave-access
technologies, such as Wi-Fi, WiMAX, etc.
- TV White Space
Wired:
- Optical Based: SDH/SONET/DWDM
Internet Traffic growth
A very well respected Cisco VNI report has this to say in
its 2014-19 report. Annual global IP traffic will pass the
zettabyte (1000 exabytes) threshold by the end of
2016, and will reach 2 zettabytes per year by 2019. By
2016, global IP traffic will reach 1.1 zettabytes per year,
or 88.4 exabytes (nearly one billion gigabytes) per
month, and by 2019, global IP traffic will reach 2.0
zettabytes per year, or 168 exabytes per month.
The India Specific numbers in the report has been
shown below. This represents the figure to be around
5 exabytes per month by year 2019
Global IP traffic has increased fivefold over
the past five years, and will increase
threefold over the next five years. Overall, IP
traffic will grow at a compound annual
growth rate (CAGR) of 23 percent from 2014
to 2019. Broadband speeds will more than
double by 2019. By 2019, global fixed
broadband speeds will reach 42.5 Mbps, up
from 20.3 Mbps in 2014
Cisco VNI Forecasts 168 Exabytes per Month
of IP Traffic by 2019 globally
Source: Cisco VNI Global IP Traffic Forecast, 2014–2019
As the telecommunications industry
experiences unexpected exponential growth
in data traffic, the demand for this
commodity has become insatiable. The
solution is to expand or retrofit existing
networks and build new networks.
Broadband Speed Aspiration vs Reality
A lot of Internet applications have come up
and the data consumption rates have been
steadily increasing at a robust speed. As per
the State of the Broadband report of
September 2014, India has a 15 per cent
Internet user penetration and is ranked
142nd, way below some of its neighbouring
countries like Bhutan and Sri Lanka. Some of
the stated objectives of the National
Telecom Policy 2012 are: Increase rural
tele-density from the current level of
around 39 to 70 by the year 2017 and 100
by the year 2020. Provide affordable and
reliable broadband-on-demand by the year
2015 and to achieve 175 million broadband
connections by the year 2017 and 600
million by the year 2020 at minimum 2
Mbps download speed and making available
higher speeds of at least 100 Mbps on
demand.
Reposition the mobile phone from a mere
communication device to an instrument of
empowerment that combines communication with proof of identity,
fully secure financial and other transaction
capability, multi- lingual services and a
whole range of other capabilities that ride
on them and transcend the literacy barrier.
The ambition to deliver 2 Mbps download
speed to users on mobile BB, with speeds of
100 Mbps or more available on demand, has
major implications for both network and
spectrum requirements.
Over the past thirty years, Internet
connection speeds have steadily increased.
Higher speeds have also been driven by the
move to higher-resolution displays. On the
demand side, the greater use of images and
video rather than plain text has also been a
driving force. This growth in connection
speeds is expected to continue in the
foreseeable future. The trend is encapsulated
in “Nielsen’s law of Internet Bandwidth”, an
empirical observation which states that a
high end user’s connection speed grows by
50 per cent per year, or doubles every 21
months.
Application Evolution and Bandwidth
Requirement
Improving and maintaining the quality of
user experience will likely be on the top of
TSPs’ agenda over the coming years. The
service providers will also need to invest in
their networks to support the expected
exponential growth in data traffic. Presently,
the increase in average bandwidth
consumed is relatively slower for following
reasons:
- Telecom companies are conservative.
- Non-availability of adequate spectrum to
provide higher data speeds.
- Users are reluctant to spend much
money on data usage.
- The user base is getting broader.
- Non-availability of relevant content.
- Bharatnet end user applications
As part of the prestigious Bharatnet project
there are a variety of applications that are to
be provided. Besides them there are few
more applications which could form a basis
for monetization. The applications can be
listed as follows:
- Mobile Backhaul: To be able to sell dark
fiber or leased Bandwidth to Mobile
Service Providers to increase mobile
penetration and provide wider coverage
and rollout obligations,
- Fixed BB: To provide fixed Broadband to
the end users,
- CATV: To provide Cable TV services over
IP or IPTV streams,
- Institutions BoD: To provide Bandwidth
on Demand to various Institutions,
- Smart Villages/Safe Villages: As the
Smart Cities initiative grows soon the
need for Smart Villages with Security and
various other application needs would
come up.
All these point to the fact that a rich demand
for data will keep on growing. A typical
Mobile backhaul would need roughly 1Gbps
to 10 Gbps in the next 5 years. Current
backhaul needs may be limited to 100-300
Mbps but that is stalling the bandwidth
demand. This bottleneck will have to be
removed paving way for deeper reach of
mobile networks. CATV streams would also
need upwards of 1Gbps bandwidth to be able
to show the plethora of SD+HD Channels
that truly give an immersive experience.
All in all a typical backhaul solution would be
needed to support in the range of 1Gbps+
traffic.
Long Haul Network Options
Generally, backhaul solutions can largely be
categorised into wired (leased lines or
copper/fibre) or wireless (point-to-point,
point-to-multipoint over high-capacity
radio links). Wired is usually an expensive
solution but offers practically unlimited
bandwidth and ease of maintenance.
Wireless backhaul is easy to deploy, and
allows moving points of presence, however,
these wireless connections are slower,
occupy spectrum that could be used by user
devices (especially as 5.8 GHz devices
proliferate), require more service/
maintenance calls (typically three times as
many) as wired backhaul, are limited in
bandwidth. They are often viewed as an
initial or temporary measure.
Wired – Optical Fiber:
Wired backhaul technologies rely on a direct
physical connection via Optical Fiber to the
repeater node or to the edge nodes. In
fibre-optic communications,
wavelength-division multiplexing (WDM) is
a technology which multiplexes a number of
optical carrier signals onto a single optical
fibre by using different wavelengths (i.e.,
colours) of laser light. This technique
enables bidirectional communications over
one strand of fibre, as well as multiplication
of capacity. An Optical Fiber network
theoretically has limitless bandwidth and
out of so many fibers in an Optical Cable
only a few are used leaving others as dark
fiber.
In fiber-optic communications,
wavelength-division multiplexing (WDM) is
a technology which multiplexes a number of
optical carrier signals onto a single optical
fiber by using different wavelengths (i.e.,
colors) of laser light. This technique enables
bidirectional communications over one
strand of fiber, as well as multiplication of
capacity. WDM systems are divided into
different wavelength patterns, coarse
(CWDM) and dense (DWDM). Coarse WDM
provides up to 16 channels across multiple
transmission windows of silica fibers. Dense
wavelength division multiplexing (DWDM)
uses the C-Band transmission window but
with denser channel spacing.
WDM, DWDM and CWDM are based on the
same concept of using multiple
wavelengths of light on a single fiber, but
differ in the spacing of the wavelengths,
number of channels, and the ability to
amplify the multiplexed signals in the
optical space
Nothing has done more to increase the
capacity of existing fiber-optic networks
than DWDM, which permits multiple data
streams to be combined on a single fiber.
Technological advancements in these
optical technologies are now promising
unlimited bandwidth which will help satiate
the bandwidth requirements of the masses
and the futuristic bandwidth hungry
applications. Wired networks in general
require certain challenges that need to be
addressed and they fall into Right-of-way
Costs, deployment costs etc. However with
the relatively higher upfront capital
investment require in the beginning they
practically offer unlimited bandwidth and
lower opex costs.
Wireless:
Wireless Backhaul options are also available
in the form of refers to technologies that use
point-to-point or point-to-multipoint radio
or microwave frequencies to transmit
signals between hub sites and an end-user
receiver. The most common wireless
backhaul, operate in the unlicensed wireless
(license-exempt) 900MHz (902-928),
2.4GHz, 5.3GHz, 5.4GHz, 5.8GHz, 24GHz,
and 60GHz frequencies of the RF spectrum.
These radio platforms are exempt from
licensing requirements. These systems,
although quick to deploy, do not promise
exclusive use of the band and are susceptible
to potential interference.
Unlicensed wireless backhaul platforms can
go distances up to 50+ miles and provide
data rates of 10Mbps to 300Mbps aggregate
throughput. These systems can be deployed
in outdoor wireless backhaul applications
such as: point to point wireless, point to
multipoint wireless, and wireless mesh
configurations. To add capacity to any
network, wireless backhaul technology
using unlicensed wireless Ethernet bridge
radios provides an inherently flexible and
scalable alternative to fibre or leased lines.
Most systems can be installed in a day or
two.
When evaluating wireless backhaul
technology, the possibility of radio
frequency interference disrupting a wireless
network link poses a concern. Radio
interference results from unwanted radio
frequency (RF) signals disrupting system
communications. Typically these signals are
at or near the same frequency as the receive
frequency of an established wireless system.
Interference can degrade a radio system's
performance and in some cases even
prevent the system from functioning at all.
The source of interference is usually other
transmitters that are very close in frequency
to the impacted system. Interference can
affect all types of radio frequencies. With
un-licensed systems it can never be
guaranteed that a system will operate
interference free and with any predictable
reliability.
The major difference between licensed
wireless and license-exempt systems is that
licensed radio users have a regulatory body
that will assist them in overcoming any
interference issues that may arise, while
license-exempt users must resolve
interference issues without governmental
assistance.
Recently though many point to multipoint
wireless systems have taken advantage of
the Wi-Fi 802.11n chip sets and can now
provide wireless bandwidth up to 300Mbps
aggregate throughput or beyond.
There various technologies in this area which
may require a Line of Sight, Near Line of
Sight or Non Line of Sight path. Compared
to other countries, in India, the quantum of
spectrum which has been unlicensed is
considerably low.
Several concerns have been raised about
aesthetics and health issues arising from
radiation hazards and the safety of telecom
towers, especially in Metro and urban areas.
There are also environmental concerns. The
use of power generators (to address the lack
of un-interrupted power supply) adds to
polluting emissions. For all these reasons,
civic authorities have imposed stringent
conditions on the erection of towers.These
include requirements such as advance
clearance from Resident Welfare
Associations (RWAs) in case of residential
areas, structural safety certificate, clearance
from pollution control authorities and fire
authorities.
At times there are huge delays in the grant of
permission. Moreover, there has been a
multi-fold increase in the levies for the grant
of permission. The Government has recently
ordered a study by 16 leading scientific
institutions across the country on the effects
of electromagnetic fields (EMF), particularly
radiating from cell phone towers, on human
health.
| S.No. |
Area |
Optical Network |
Wireless Backhaul |
| 1 |
Ease of deployment |
Time consuming |
Relatively less time consuming |
| 2 |
Cost of deployment |
Costly |
Half or less as costly |
| 3 |
Maintenance |
Less |
Relatively much more time consuming |
| 4 |
Spectrum |
Not applicable |
Works in Unlicensed band hence is prone to interference. Also lesser free band available in India |
| 5 |
Bandwidth |
Practically unlimited bandwidth available |
Very limited bandwidth available around 200-300 Mbps |
| 6 |
Repeater distance |
Ranging in 80km-120km (even much longer options available) |
Available Bandwidth is a function of distance of the link.
As the link size increases available bandwidth decreases.
Typical distance could be 18-20km |
| 7 |
Reliability |
Relatively much reliable |
Prone to weather conditions |
| 8 |
Use in critical conditions |
Reliability is high hence critical applications require Optical Network |
Reliability is low hence critical applications such as telemedicine, emergency may not be suitable to run over them |
| 9 |
Infra Requirement |
Ducting and trenching |
Towers to be erected |
| 10 |
Lifespan |
Typical lifespan of 20-30 years |
Lifespan only good as long as Bandwidth limits are not breached which could be easily outdone in next 2-3 years |
| 11 |
Monetization |
Possible by selling dark fiber |
No avenues |
| 12 |
WPC Clearance |
Not Applicable |
Need to have WPC Clearance |
Conclusion
After careful consideration and analysing pros and cons of both the options it would be possible to make a fair case of Optical Network
deployment to cater to long term needs of broadband penetration.
Wireless even as an alternative for faster rollout may not achieve the desired objective and in a few years’ time the network investment would
have been lost. On the other hand Optical Network deployment makes a wise decision even though its more time consuming and costly but
would be able to address the ever growing bandwidth needs of the masses.
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