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Now a day smart phone users are increased and the energy consumption problem in mobile industry has become crucial. For the growth of mobile industry energy efficiency of the system must be improved. In order to improve the methods of network energy usage usually reduction of the Base Stations are to be employed. The mobile industry faces a critical energy consumption challenge. By 2014 smart phones will exceed 1.82 billion units and surpass PCs as the most common web access devices. That’s why it is one of the important things. As all know that a smart is mainly for easy access to the network at anytime and anywhere. So it employs powering up all the Radio Base Stations (RBS’s) at maximum power. Since there are more number of service providers competition exist at the field of telecommunication. So it yields in more energy consumption to get monopoly among them. In the field of engineering, a system is usually designed to transform energy to useful work. Energy Efficiency can therefore be defined as the ratio of useful work to the total supplied energy. The useful work in a communication system refers to the effort to deliver modulated signals for information exchange. The definition of Energy Efficiency varies according to measured objects. There are two basic methods to measure Energy Efficiency. One way is to define Energy Efficiency as the ratio of efficient output power/energy to total input power/energy. This definition is widely used by systems and components such as power supply, Power Amplifiers, and antennas. The other way defines Energy Efficiency as the performance per unit of energy consumption. The seminar gives a brief description about the methods to manage the network energy even when the on time access to network by mobile phones. Also gives a summary about existing and latest methodologies about the management in RBS’s.
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04/13/2023SNMIMT Dept. OF EEE 1
04/13/2023SNMIMT Dept. OF EEE 2
NETWORK ENERGY SAVING TECHNOLOGIES FOR GREEN
WIRELESS ACCCESS NETWORKS
MADHAVADAS MS7 EEEROLL NO. : 24
Guided by,ANOOJA C LAsst. PROFESSORDept. OF EEE
CONTENTS
1. INTRODUCTION
2. ENERGY EFFICIENCY
3. RBS ENERGY CONSUMPTION
4. ENERGY SAVING METHODS
TIME DOMAIN
FREQUENCY DOMAIN
SPATIAL DOMAIN
5. COMPARISON
6. CONCLUSION
04/13/2023 3SNMIMT Dept. OF EEE
1. INTRODUCTION Mobile industry is facing a crucial energy crisis.
Increase in network data volume caused high energy demand and
increased CO2 emission.
Energy is consumed by the network components not only to deliver
signals, but also for cooling, cabling, converting etc.
All methods in this topics are for Long Term Evaluation (LTE)
scheme.
Soft methods such as signal modification cause only a small
reduction of energy usage.04/13/2023 4SNMIMT Dept. OF EEE
2. ENERGY EFFICIENCY♥ Effort to deliver modulated signals for information exchange
(WIRELESS EE).♥ Increase in network data volume caused increase in energy
consumption by Radio Base Stations(RBS).♥ All cellular companies are only focused on performance.♥ Global System for Mobile communication have EE of RBS
side about 3.1% in case of 3G it’s about 20%.
04/13/2023 5SNMIMT Dept. OF EEE
ENERGY EFFICIENCY
Ratio of efficient output power/energy
to total input power/energy
Performance per unit of energy
consumption
04/13/2023 6SNMIMT Dept. OF EEE
SHANNON’S FORMULA
R- Bit rate of information B- Band width
P- Received power N0- Noise power spectral density
Unit – Bits/Joule04/13/2023 7SNMIMT Dept. OF EEE
3. RBS ENERGY CONSUMPTION MODEL
04/13/2023 8SNMIMT Dept. OF EEE
The most power consuming equipment in RBS is Power Amplifiers
(ie. PA’s).
Shutting down PA offers less energy consumption.
Contd…
04/13/2023 9SNMIMT Dept. OF EEE
4. ENERGY SAVING METHODS
04/13/2023 10SNMIMT Dept. OF EEE
4.1 TIME DOMAIN4.1.1 PA off at signal free
› Straight forward approach.
› PA operation time ≈ 47%.
04/13/2023 11SNMIMT Dept. OF EEE
4.1.2 Multicast Broad cast Single Frequency Network (MBSFN)
› Reference signal reduction.
› Used to provide services like mobile TV.
› PA operation time ≈ 28%.
04/13/2023 12SNMIMT Dept. OF EEE
4.1.3 Extended cell Duplex Transmission (DTX)› Further reduction of RS’s.› If no downlink, no need to transmit 1-4&6-9 sub frames.
› PA operation time reduced to 7.1%.
Reduction of PA on time; used at rural areas. Unpredictable problems while synchronizing with user. In DTX mode a pilot design is required. Used in a single RBS.
04/13/2023 13SNMIMT Dept. OF EEE
4.2 FREQUENCY DOMAIN
4.2.1 Band Width Reduction
› Band width is reduced when increase in downlink takes
place.
› Frequency change must be within the standard limits.
› Either change in carrier frequency and bandwidth or
change in bandwidth without changing carrier frequency is
employed.
› PA’s are not shut down; But it drain less energy than usual.04/13/2023 14SNMIMT Dept. OF EEE
4.2.2 Carrier aggregation
› In an RBS carriers are aggregated in groups & each group is
served by individual PA’s.
› When an aggregate downlink is absent, corresponding PA can be
shut down.
Efficiency of frequency domain is limited.
Normally combined with energy saving methods of other
domains.
Less impact on User Evaluation.
Used in a single RBS.04/13/2023 15SNMIMT Dept. OF EEE
4.3 SPATIAL DOMAIN
4.3.1 Reduce antenna number
› Most commonly used method.› Combined with bandwidth reduction technique for low
traffic mode.› To maintain same strength of spectrum, additional control
signals are needed.› May lead to service degradation and interruption.
04/13/2023 16SNMIMT Dept. OF EEE
4.3.2 Switch on/off cell
› When traffic load is low, some cells can be shut down.
› A set of cells where shut down and User Evaluation is handle
over to remaining cells.
› The cells are either shut down by direct signaling between
RBS’s, or by providing sequential control.
› Another approach is Hierarchal Cell Structure (HCS), Here
macro cells are always on for coverage and micro cells are used
to boost capacity. And are operates at heavy loads.
04/13/2023 17SNMIMT Dept. OF EEE
4.3.3 Layered structure
› Same as HCS, macro cells serve wireless wide area network and
micro cells serve local area network.
› Macro cells can be shut down by transferring loads to micro cells.
› Improved energy efficiency and coverage are obtained.
› Flexible than HCS.
Can be extended up to network basis and is more flexible.04/13/2023 18SNMIMT Dept. OF EEE
4.4 HYBRID SOLUTIONS› Combination of different domain solutions are used to attain
maximum EE.
In low down link traffic single carrier under carrier
aggregation method with single antenna and maximum
MBSFN sub frames in a frame.
› Reducing antenna number and bandwidth cause reconfiguration
time about 10ms.
› Hybrid solutions are recommended only in semi-static traffic
conditions. 04/13/2023 19SNMIMT Dept. OF EEE
5. COMPARISON
04/13/2023 20SNMIMT Dept. OF EEE
Merits
› Low power consumption.
› Improved downlink speed.
› Increased data volume capacity.
Demerits
› Bulkier circuit.
› High installation cost.
› Need of regular maintenance.
• In full load cases hybrid solutions are employed• At no load cases DTX or MBSFN is employed.• MBSFN at no load gives high performance.
Contd…
04/13/2023 21SNMIMT Dept. OF EEE
6. CONCLUSION
Energy consumption problems in wireless networks
can be reduced by energy saving LTE systems.
Energy Efficiency of RBS varies with traffic
problems. And it can be reduced by Tri- Dominal
approch.
Most of the approaches, hybrid approach gives best
result.04/13/2023 22SNMIMT Dept. OF EEE
REFERENCES
IEEE Wireless communication.
Wikipedia the free encyclopedia.
Bharath Sanchar Nigam Limited.
Finnish Funding Agency for Technology and Innovation.
B. Gammage et al., “Gartner’s Top Predictions for IT Organizations and
Users, 2010 and Beyond: A New Balance,” Gartner Report, Dec. 2009.
R. Tafazolli et al., “eMobility Mobile and Wireless Communications
Technology Platform: Strategic Applications Research Agenda,” Net!Works
European Technology Platform, July 2010, http://www.networksetp.eu04/13/2023 23SNMIMT Dept. OF EEE
04/13/2023SNMIMT Dept. OF EEE 24
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