Green Cellular Networks:
A Survey, Some Research Issues
and Challenges
Nourah Alhassoun
February 29, 2012
Part I
Objective:
 A brief survey of methods to improve the power efficiency of cellular
networks and explore some research issues and challenges
 Suggest some techniques to enable an energy efficient or green cellular
network
Results:
 A survey on methods to obtain energy savings in base stations such as
architectural changes in base stations and heterogeneous network
deployment
 Propose a research vision by using some techniques(cognitive radio
and cooperative relaying technologies) to make energy more efficient
Part II
Important Aspects of a Green Networking:
I. Defining Green Metrics
II. Architecture Changes in Base Stations
III. Network Planning
IV. Addressing Energy Efficiency in Future Generation
Wireless Systems
V. Some Broader Perspectives
I. Measuring Greenness
Energy Efficiency Metrics:
 Facility-level: High-level systems where equipment is
deployed
 Equipment-level: Evaluate performance of an individual
equipment
 Network-level: Assess the performance of equipment with
the consideration of features and properties
II. Architecture: Energy Saving in
Base Stations
 Minimizing BS Energy Consumption
 Improvements in Power Amplifier: Switch mode PA
 Power Saving Protocols: Sleep Mode
 Energy Aware Cooperative BS Power Management
 Cell Zooming: BS can adjust its size according to
network or traffic situation
 Renewable Energy Resources
 Solar and Wind Energy instead of off-grid sites
III. Network Planning
Heterogeneous Network Deployment:
Based on smaller cells such as micro, pico and femtocells
 Advantages:
 Energy consumption of the network can be reduced up to 60%
compared to a network with macro-cells only
 Smaller cells use higher frequency bands to provide high data
rates
 Draw Backs:
 The efficiency of macro-cell Base Station might be reduced
Part III
IV. Addressing Energy Efficiency in
Future Generation Wireless Systems
Enabling Technologies:
 Green Communication via Cognitive Radio:
 Purpose: Collect information on the spectrum usage and
access the unused frequency bands
 Manage the spectrum optimally and dynamically
 Green Communication delivered by Cooperative
Relays:
 Purpose: Improvement in throughput and coverage
 Provide service to more users using less power
IV. Addressing Energy Efficiency in
Future Generation Wireless Systems
 Low Energy Spectrum Sensing
 Cognitive Radio: design low complex cyclostationary
detectors instead of energy detectors
 Energy Efficient Resource Management with Applications
in Heterogeneous Networks
 Relay placement, optimal relay selection criterion
 Addressing Uncertainty Issues
 Cognitive Radio: did not take into account the effect of
imperfect sensing
 Cooperative Relays: optimal relays with perfect CSI
VI. Some Broader Perspective
Ideas to achieve energy efficient cellular network:
 Statistical Power Profiles:
Dynamic algorithms can be designed to switch BS to different
power profile appropriate for that time of the day
 Smart Grid Technology:
Adding measurement sensors which can update the status of BSs
then transmit them to other BSs and smart grid control system
 Embodied Energy:
Reducing the number of BS since embodied energy accounts for a
significant proportion of energy consumed by the BS
Energy Saving Obtained by Some of
the Discussed Techniques
Reference
Hasan, Z. Boostanimehr, H. 2011. “Green Cellular Networks: A survey,
some research issues and challenges”. IEEE Communications Survey &
Tutorials. V13,2,4.