ON/OFF Switching Strategies of eNodeB for Green LTE Networks

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12 Δεκ 2013 (πριν από 3 χρόνια και 8 μήνες)

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ON/OFF Switching Strategies
of eNodeB
for Green LTE Networks

Abstract:


The enormous growth in broadband communications over the last decade has propelled the ICT
sector to become one of the main industries that drain a large percentage of annual global
energy consumption.
This has coincided with an era which is witnessing dec
lining availability of
traditional energy resources

and proactive research for renewable green/clean sources of
energy.
In cellular communications, base stations are typically responsible for nearly 60% of the
energy demand associated with cellular service
s. Accordingly, recent research on energy
efficient strategies to manage base station operation has become of the ultimate essence.
In
this
contribution
,
the aim is to investigate optimal switching ON/OFF strategies of eNodeB for
green LTE networks. The ap
proach adopted formulate
s

the problem as an optimization
algorithm

that minimizes the number of ON base stations within a given area in
correspondence to active traffic loads
and transmission power requirements
while maintaining
individual subscribers’ QoS

constraints.

Over the last decade, energy consumption of
the
information and communication technologies
(ICT)
sector
has become a key issue due to both economic
and environmental
reasons.
ICT has
been claimed to be responsib
le for 2%
-

10% of annual world
wide consumption

[1]
.

Moreover,
o
n the environmental side,
ICT is responsible for an insignificant percentage of global C0
2

emissions
[2]
. With projections for 2013 that indicate more than 1.82 billion smart phone units
representing the most common alternative for web access (exceeding PCs)
[3]
, the future of ICT
envisions a predominant
expansion in cellular/wireless infrastructures with significantly large
percentage of ICT energy demands.
Statistics show that base stations drain the h
ighest amount
of energy within the network of mobile operators (nearly 57% of operators’ consumption)
[4]
.

Accordingly, research on energy savings techniques
of ba
se station operation

has become of
significant importance over the last couple of years

[5]
.

Due to the alternating nature of cellular traffic demand between day
and night as well as office
and residential areas, s
trategies for
switching

ON/OFF

the radio base stations (eNodeB in LTE)
has been

one of the main active topics among the techniques of energy saving in base stations
operations
[6]
,
[7]
,

[8]
.
This could be particularly evident
if
the
maximum
base station power
transmission power
at the scale of 30W
-
40W
is compa
red to base station operations cost at the
scale of 1500 W
[9]
.

Strategies of switching
ON/OFF the appropriate eNodeB

in response to active traffic demand
variations have varied form load
-
based to UE distance
-
based techniques. In the load
-
based
approach,
the eNodeB depends on a set of tra
ffic thresholds that
are

predefined during
configuration

and eNodeB with active traffic load below the preset thresholds are switched OFF
[8]
. In UEs
distance
-
based approach, eNodeB are ranked based on the average distance
between them and their active served mobile subscribers
.
The eNodeB with the highest
average distances are selected to have priority for switch OFF. In both approaches, active

users
o
f the switched
OFF

eNodeB
must be diverted to the

next nearest eNodeB

without jeopardizing
their QoS requirements
.

In this contribution, the problem of ON/OFF
switching
strategies in LTE networks will be
formulated as an optimization
algorithm

that consid
ers both the
power transmission
requirements

of

eNodeB
to serve

active mobiles
users
within its coverage range
as well as the
average power requirements for

eNodeB
to support

mobiles
users
that
are
served by neighbor
base stations. The
addition
to
include
the relation between

eNodeB
and

mobile

user
s served by
neighbor base station in the process of selection of
eNodeB

that should be switched OFF

contributes in providing guarantees that traffic of switched OFF
eNodeB

could have a better
chance of being suppo
rted at their QoS requirements. Furthermore, the research in this
contribution shall also incorporate the effect of fractional reuse in LTE on ON/OFF
switching
strategies which has been overlooked in the literature

References:

[1].

Global Action Plan, “An ineff
icient truth
,
” http://www.globalactionplan.org.uk, Global Action Plan Report, Dec.
2007

[2].


http://green
-
broadband.blogspot.com/

[3].

B. Gammage et al., “Gartner’s Top Predictions for IT Organizations and Users, 2010 and Beyond: A New
Balance,”
Gartner Report
,
Dec. 2009.

[4].

C. Han et al., “Green Radio: Radio Techniques to Enable Energy
-
Efficient Wireless Networks,”
IEEE Commun.
Mag.
,
vol. 49, no. 6, June 2011, pp. 46
-
54.

[5].

T. Chen, et al., “Network Energy Saving Technologies for Green Wireless Access Networks,”
IEEE
Wireless
Communications,
vol.
,

no. Oct. 2011, pp. 30
-
38.

[6].

A. Bousia, et al., “”Green” Distance
-

Aware Base Station Sleeping Algorithm in LTE Advanced,”

International
Conference on Communications (ICC 2012),

June 2012.

[7].

W. El
-
Beaino, et al., “
A Proactive App
roach for LTE Radio Network Planning with Green Consideration
,”
19
th

International Conference on Telecommunications (ICT 2012),
pp.

1
-
5, Apr. 2012.

[8].

C. Zhong, and T. Yang, "A Priority
-
aware Hybrid Multi
-
hop Energy Saving Strategy for Inter
-
eNB Scenario2,"

IEEE 22nd International Symposium on Personal Indoor and Mobile Radio Communications
2011
(PIMRC

2011
),

pp
. 1541
-
1545, Sept. 2011


[9].

O. Arnold, et, al., "Power Consumption Modeling of Different Base Station Types in Heterogeneous Cellular
Networks,"

Future N
etwork and Mobile Summit, 2010
,
pp. 1
-
8, June 2010.