Global ICT Standardization Forum for India (GISFI)
Title:
GISFI-FRN: GERAN Deployment Architectural Options for Sustainable
Operations
Source: GISFI-FRN Chair
Author(s): Krishna Sirohi
Contact krishna.sirohi@vnl.in, +919899488800
information:
Purpose: For discussion and to take relevant portions to start action on work item
“GISFI-FRN: Rural System Requirements” of question “GISFI-FRN-Q.
Sustainable Rural telecommunication Infrastructure”.
Doc number: GISFI_FRN_201109114
Meeting: GISFI#6, Neemrana, India, 27th -29th September, 2011
1. Introduction
Suitable deployment architectures for the mobile networks greatly decides the initial infrastructure
cost, operating cost, Electromagnetic radiation, necessary initial capacity of the network, ability to
increase capacity on demand, spectrum requirements, power consumption requirements and hence
its ability to be operated with non-polluting power sources. All such factors collective decides the
operational sustainability of the mobile network. The Power consumption of currently deployed
GERAN based Mobile networks in India is extremely high and due to poor grid power situation in the
country, every base-station sites is operated by diesel generators causing alarming level of carbon
emissions. In this paper some alternate deployment options for the existing mobile network has
been presented. It is recognized that with current deployment architectures with the available
products, it is economically not feasible to achieve 100% Green Telecom in urban areas due to
varying traffic requirements in different areas. The deployment architecture as evolved 20 years ago
were based on totally different requirement of traffic generation and user patterns. Therefore it is
necessary to define the problem in current perspective. Running all the high capacity telecom
installation, as deployed currently, on non-polluting source of energy is economically not viable and
become one of the main factor operational un-sustainability in many parts of the world. However
alternative deployment architectures and the usage of the energy efficient telecom equipments
potentially allows to lower carbon emissions significantly and increases other benefits ensuring the
sustainable operations.
2. Classification of Mobile Network deployment scenario
Mobile Networks can be classified into following categories:
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1. Urban Very High Density Network:
e.g., Connaught Place in New Delhi
2. Urban High Density Network:
e.g., Gurgaon Udyog Vihar
3. Urban Medium Density Network:
e.g., some Urban Residential Area
4. Rural Low Density Network
The entire rural India with 850 million people.
Alternative deployment strategy for each is proposed in subsequent sections.
3. Urban Very-high Density Network
The commercial areas of the main city centres with very high and uniform user density spread are
considered as candidates for this category. Alternate Deployment Strategy for this category is as
follows:
i. Completely eliminate all high rise Telecom Towers to regain the aesthetic look of the city and
save on telecom infrastructure.
ii. Instead, distribute RF from low height existing infrastructure of street lamp poles or building
roofs/walls for outdoor coverage and from building ceiling/walls for indoor coverage.
iii. Utilise Distributed Antenna Systems (DAS) for suitable radio distribution ensuring 100%
coverage and at the same time more flexible and better network capacity.
iv. Use very high capacity Base-stations to provide a large cell size with controlled shape for
outdoor coverage thus minimizing requirement for frequent handovers and eliminating need
for hierarchical cell structure.
v. Complete elimination of Diesel Generators, in future, with more efficient power storage
technology.
Such deployment methods are additionally suitable for shared mobile network infrastructure Adoption
of such deployment strategy in network sharing mode may provide additional benefits to Telecom
Service Providers with small portion of allocated GSM spectrum to achieve required network capacity.
4. Urban High Density network
The urban areas with overall high density and with non-uniform density spread are considered as
sample candidate for this category. This category area could be classified into two sub parts. The
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first part covers roads with high mobility of users and residential areas with relatively low user
mobility. The second part represents very high density hot spots within commercial building and
small sized market places quite separated from each other. Low user capacity, medium data rate and
high mobility are the key characteristic for the first part while high capacity, high data rate and low
mobility are for the second part. Alternate Deployment Strategy for this second category is to
establish a Two Tier Mobile Network. The low capacity Tier1 (T1) network provides outdoor Macro
(Umbrella) Cell coverage to cover entire area as large cell solution and caters for high mobility at
vehicular speed at roads. A large part of the network capacity is offloaded to the Tier2 (T2) Network.
The Tier2 (T2) network provides indoor coverage for all commercial building and outdoor coverage
to urban hotspots and the streets.
The T1 Network characteristics due to lower traffic capacity requirements are:
i. The towers height is same or slightly higher compared to the conventional towers.
ii. The total radiated power per carrier base-station is lower than the conventional base-station
which in turn reduces radio interference.
iii. Number of base-station sites is reduced by a factor of cabled (optical or copper) 4-8 depending
on the finer user patterns. This allows for easy provision of backhaul.
iv. Frequency spectrum requirement for T1 network is lower than conventional architecture
which allows the “saved” spectrum to be used for the T2 network.
Increased traffic capacity requirements of T1 network are taken care of by addition of more T2
Network base stations having primarily a low range non-overlapping coverage. This eliminates the
need for repeating radio re-planning and optimization exercise of the T1 network leading to
significant reduction in OPEX.
The T2 Network is composed of small Micro/Pico cell Base Stations using low height existing street
lamp poles or building roofs/walls for outdoor coverage and building ceiling/walls for indoor coverage.
This low powered non-overlapping small cells deployment scenario allows higher frequency re-use
and hence lowers the overall frequency spectrum requirements.
Depending on their location, majority of T2 sites will have wireless backhaul utilising T1 Base-station
sites with Line of Site (LOS) Point-to-Multipoint (PMP) technique. However, some may utilise already
existing cabled (optical or copper) backhaul. Additionally, utilization of Distributed Antenna Systems
(DAS) enables better RF distribution and hence ensures 100% coverage and a flexible capacity per cell
site.
The above will enable to build high capacity network for an operator even with smaller amount of
allocated spectrum and also allows to pool spectrum for a shared access infrastructure using publicly
available street lamps, traffic lights, etc.
Potential gains of the chosen Alternate Deployment Strategy are:
i. Huge telecom infrastructure cost saving on account of significant reduction of high rise towers.
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Global ICT Standardization Forum for India (GISFI)
ii. Majority of the users are served from near-by low RF powered base stations and hence
reducing overall power consumption which in turn leads to ‘Greener Telecom Networks’.
iii. It is possible to completely eliminate Diesel Generators with currently available power storage
technology.
iv. Judicious use of frequency spectrum leads to much efficient spectrum usage. Availability of the
required spectrum is one of the most alarming problems in urban high density networks.
v. Two Tier network enables higher network capacity utilization and better potential for RoI.
5. Urban Medium Density Network
The urban areas with overall medium user density and with uniform density spread are considered as
typical candidates for this category which utilises today’s classical Conventional Deployment strategy
in the manner which is similar to developed countries.
6. Rural Low Density Network
The rural areas network is characterized as overall low density and with non-uniform density
spread. Over 75% geographical areas have agricultural fields, forests and other utility where people
density is less than 100 people per sq kilometres while there are concentrated pockets of people as
villages, have much higher population density up to 2000 to 4000 people per sq kilometre. Such
villages are normally separated by 2-3 kilometres, having population from 500 to 5000 people. The
total geographical area covered by the Villages and its community activities including houses,
schools, hospitals, kisan-seva-kendras, rural business enterprises is less than 25%. These factors
characterizes the Rural Low Density Network category. This category area could be classified into
two sub parts. The first part covers roads, agricultural fields, forests and other utility area with much
less population density with high mobility of users. The second part, the villages, represents
relatively higher density hot spots. Very Low user capacity, medium data rate and high mobility are
the key characteristic for the first part while the medium capacity, high data rate and low mobility
are for the second part.
Alternate Deployment Strategy for this second category is to establish a Two Tier Mobile Network.
The low capacity Tier1 (T1) network provides outdoor Macro (Umbrella) Cell coverage to cover
entire area as large cell solution and caters for high mobility at vehicular speed at roads. A large part
of the network capacity is offloaded to the Tier2 (T2) Network. The Tier2 (T2) network provides
indoor coverage for all the houses, schools, hospitals and other buildings and outdoor coverage to
the entire village streets and outskirts.
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Global ICT Standardization Forum for India (GISFI)
The consolidated view of the deployment architectural principles is presented in the following
figure-1:
Figure-1: Deployment Architecture for Rural Area covering large cluster of villages.
Considering the availability separate T2 networks to serve village population, the T1 Network
characteristics can be summarised as:
i. The towers height is same as the towers in the conventional deployment architecture (Single
Tier Deployment with uniform capacity density deployed).
ii. Since the T1 network is not expected to provide indoor coverage in villages, the network can
be planned at -95 dBm at the cell boundary instead of -75 dBm in case of conventional one.
This will provide much larger cell coverage from the T1 BTS sites and the total number of
required T1 cells sites would be significantly less by a factor 3-4.
iii. The total radiated power per carrier base-station is lower than the conventional base-station
which in turn reduces radio interference.
iv. Since the capacity requirement of the T1 cell sites is very much less, total power
consumption of the entire site will be significantly less and will make them economically
viable if required to be operated with non-polluting power source like Solar, Wind etc.
v. The T1 Cell sites additional have a requirement to provide wireless backhaul to the T2 cell
sites covering individual villages.
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vi. Frequency spectrum requirement for T1 network is lower than conventional architecture
due to its much less capacity requirement which allows the “saved” spectrum to be used for
the T2 network.
vii. Since the T1 network is not subjected to meet ever increasing capacity requirement, it
practically separate capacity from coverage.
Increasing traffic capacity requirements of the entire rural network is taken care of by addition of
more T2 Network base stations having primarily a low range non-overlapping coverage. This
eliminates the need for repeating radio re-planning and optimization exercise of the T1 network
leading to significant reduction in OPEX.
The T2 Network is composed of small Micro/Pico cell Base Stations using low height Poles on ground
or roof based for outdoor coverage for the individual village with adequate signal strength to provide
indoor coverage, on streets and in its near outskirts. This low powered non-overlapping small cells
deployment scenario allows higher frequency re-use and hence lowers the overall frequency
spectrum requirements.
T2 sites will have wireless backhaul utilising T1 Base-station sites with Line of Site (LOS)
Point-to-Multipoint (PMP) technique.
Such rural deployment architecture will enable to build adequately high capacity network in the rural
area for one or shared by multiple operators with much smaller amount of allocated spectrum.
Potential gains of the chosen Alternate Deployment Strategy are:
i. Huge telecom infrastructure cost saving on account of significant reduction of high rise
towers.
ii. The users in each village are served from near-by low RF powered base stations in the same
village instead of being served from few kilometres away. Limited capacity requirement to
meet one village population by single BTS cell site and the need to radiate significantly low
power due to small range requirement reduces the overall power consumption requirement of
each village site that can also be operated by non-conventional (non-polluting) source of
power leading to build ‘Greener Telecom Networks’.
iii. Due to low population density of the rural network, the conventional deployment architecture
always leave some village without adequate radio signals and due to economic reasons, it will
never justified to install another large cell conventional BTS site. However the small cell BTS
site will always be justified and in no case any village will remain debarred from mobile
telecom service.
iv. In addition to have GSM based Voice and GPRS/EDGE based narrow band packet mode
services, it is possible to deploy additional capable broadband base stations with very high
data rate capabilities in the small cell village area, with low mobility capability. This aspect
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Global ICT Standardization Forum for India (GISFI)
makes this rural deployment architecture future safe from radio technology enhancements.
7. Proposal:
a) It is proposed that GISFI-FRN extract Rural Deployment related information from this paper
and use is as basis to start the Work Item “GISFI-FRN: Rural System Requirements” of
question “GISFI-FRN-Q. Sustainable Rural telecommunication Infrastructure”.
b) It is also proposed start another study Work Item on “Appropriate Deployment Architectures for
Future Mobile Networks”. This work item should include all the legacy technology as
GSM/EDGE/3G and the IMT-Advanced Technology. The information in this paper should be
taken as initial input on legacy network which need to be further refined and to be added with
the necessary information of other technology networks.
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