Energy Efficiency and Superlative TTT for Equitable RLF and Ping Pong
in LTE Networks
Ghazanfar Ali Safdar
Springer Science+Business Media, LLC, part of Springer Nature 2018
Data hungry users engage radio resources over long periods of time thus resulting into higher energy consumption by Base
Stations (BSs). Mobile operators’ operational expenditure (OPEX) is directly affected by augmented electricity bills due to
increased power consumption, thereby ensuing reduced economic and environmental benefits, i.e. profitability of vendors and
green communication accordingly. This work provides performance analysis of our proposed reduced early handover (REHO)
scheme which results in increased energy efficiency. Impact of reduced energy consumption is shown on OPEX, as well as
greener aspects are investigated by inclusion of real life commercial tariffs adopted by one of the mobile operators in the UK.
Performance analysis revealed that varying time to trigger (TTT) values significantly impact radio link failure (RLF), ping pong
effect as well as call drop ratio (CDR) and Handover ratio (HOR), at changing users’ velocities. Paper investigates and provides a
very useful insight for superlative value of TTT for unbiased RLF and Ping Pong, which can help vendors not only to achieve
increased energy efficiency, but also maintain other salient performance parameters within acceptable limits. The work also
achieves the fact that the time difference in terms of transmission time intervals (TTIs) for reduced early handover in REHO,
always remain the same irrespective of the value of TTT, thus ensuring that REHO continuously achieves increased energy
efficiency compared to LTE standard.
There is tremendous increase in number of subscribers and
volume of data traffic in cellular networks. Long Term
Evolution (LTE) technology has been adopted by operators
enabling them to fulfil requirements of increased users .
In parallel, operators are expanding network infrastructure
by deploying additional Base-stations (BS) to meet user’s
ever-increasing capacity needs. The continuous operation of
growing BSs directly effects power consumption and raises
operator’s OPEX, thus resulting in to lessened profit.
Additionally, the power consumption perspectives of in-
creased BSs also significantly contribute in global warming.
The information and communication technology (ICT) has
approximately contributed 10% in global power consumption
in year 2013 , while cellular networks constitute major part
in ICT involvement. In the same context, ICT is responsible
for 2% of global CO
emission while it is likely to be doubled
(4%) by year 2020 thus forming significant contribution in
global warming . In cellular networks, BSs are main
power-hungry elements responsible for approximately 60%
of total power consumed by network [4, 5]. Ranging from
carrier aggregation, cell size adjustments, efficient network
management, and intelligent turning off of BSs etc., existing
literature boasts itself from several energy efficient schemes
for cellular networks. Depending on user equipment (UE)
location, energy saving in LTE networks can be achieved by
adjustment of coverage area, i.e. through cell size adjustments.
Renewable green energy sources have also proven to be
friendly towards reduced grid energy consumption, thereby
achieving compact OPEX for operators. Carrier aggregation
is widely employed by researchers to result into reduced con-
trol overhead, thereby achieving improved energy efficiency
[6, 7]. Energy saving can also be achieved by monitoring
traffic load and turning off BSs during off peak time periods.
The concept of switched off BSs based on traffic intensity
* Ghazanfar Ali Safdar
School of Computer Science, University of Bedfordshire, Luton LU1
Mobile Networks and Applications