Green Wireless Cellular Networks Powered by the Smart Grid

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WHEN THE SMART GRID MEETS ENERGY-EFFICIENTCOMMUNICATIONS: GREEN WIRELESS CELLULAR

NETWORKS POWERED BY THE SMART GRID

Authors

S. Bu, F. R. Yu, Y. Cai, and X. P. Liu

IEEE Transactions on Wireless Communications, Aug. 2012



Outline

1. Introduction

2. System Model

3. Problem Formulation

4. Analysis of the Proposed Two level Game

5. Simulation Results and Discussions

2

1. Introduction

6. Conclusion



1. Introduction

Green Communications Network Design

Objectives:

1. Reduce the amount of energy consumption by

the networks’ BSs

2. Maintain a satisfactory QoS for the users

3

Motivations for Green Radio Communications

Service Provider’s

Financial Considerations

Environmental

Considerations

- Half of annual operating

expenses are energy costs

- Currently, 2% of CO2

emissions from telecom.

E n er g y C on s u

m pt i on



1. Introduction Cont.

Solutions for Energy Aware Infrastructure

Renewable

Energy Sources

Heterogeneous

Cell Sizes

Dynamic

Planning

- Reduce CO2emissions by using

renewable energy

- Reliability issues

- Macro-cells Femto-cells

- Balance of

different cell sizes

is required

- Exploit trafficload fluctuations

- Switch off

available resources

at light traffic load

4




Temporal fluctuations in traffic load

Resources on-off Switching

Radio transceivers of

active BSs

Entire BS switch-off

5




Dynamic planning challenges

Service Provision Guarantee

Increase cell

radii

Relaying

mechanism

Network

cooperation

- Coverageholes & inter-cell

Interference

- Unreliable fordelay sensitive

applications

- Alternatelyswitch on-off

resources

6

CoMP

Extend BSs coverage area

Ensure service quality for users in off cells



1. Introduction Cont.7

Wireless Cellular Network Powered by the Smart Grid

Consider not only energy efficient communications but also the

dynamics of the smart grid in designing green wireless cellularnetworks

Dynamic operation of BSs

depends on: traffic, real time

electricity price provided by SG,

and pollutant level associated

with electricity generation

Active BSs decide on which retailers to

procure electricity from and how much

electricity to procure, considering the

pollutant level of each retailer and the

price offered by the retailer

Novelty



Outline

1. Introduction

2. System Model




8

6. Conclusion



2. System Model9

• Cellular network powered by the smart grid

Real-time pricing DSM in SG CoMP & service blocking BSs electricity consumption



2. System Model Cont.10

A. Real time pricing DSM:

• Dynamic pricing: effective DSM strategy to encourage users

to consume electricity more wisely• Electricity market liberalization: retailers compete with each

other and aim to achieve the highest individual profits by

adjusting the price offered to users in each region

• Real time pricing: prices offered by retailers changefrequently to reflect variations in the cost of the energy

supply




B. CoMP Communication:

• BSs are turned off when

traffic is low, real timeprice is too high, or

pollutant level of the

electricity retailer is too

high

• CoMP is used among active BSs to guarantee the coverage

requirements

• Assume i BSs in each CoMP cooperation cluster

• All possible combinations of BSs in the cluster are 2 ,




C. Service Blocking:

• The uplink sum capacity for the cluster is given by

Identity

matrixTerminal

power

Channel

matrix

• The number of channel available in cluster is given by

BW allocated

for each CoMP

cluster

Effective BW required for

service, considers packet-

level QoS (delay, loss)




• Service blocking probability in each cluster is given by

Traffic arrival rate

Average service

rate

•Relationship between service blocking probability and acombination set is given by




D. BSs Electricity Consumption Model:

• Active BS energy consumption is given by

BS Transmission Power

Account for antenna

setting, carrier freq.Path loss

exponent

Inter-site

distance

Signal Processing Power

Base line signal

processing per BS

Backhaul Power

Req.




• Active BS energy consumption is summarized as



Outline

1. Introduction

2. System Model




16

6. Conclusion



3. Problem Formulation17

Two steps:

1. Each retailer in the smart grid provides the real-time price

to the BSs in each cluster

2. Each cluster decides how many BSs turned on, and how much

electricity to procure from each retailer

Stackelberg Game

Leaders Followers

Each retailer in the SG BSs in one clusterSG level Game Cellular network

level Game



3. Problem Formulation Cont.18

A. Cellular Network Level Game:

• BSs Obj.: obtain the lowest service blocking probability with

least possible costs

• BSs decide, to maximize a net utility:

1. How many BSs will be active in a cluster?

2. How much electricity is procured from each retailer?




• Net utility of all BSs in a cluster:

Service blocking utility function Total electricity cost Total pollutant level

• BSs Optimization Problem:




B. Smart Grid Level Game:

• Retailer n utility function is given as:

• Retailer n Optimization Problem:



Outline

1. Introduction

2. System Model




21

6. Conclusion



4. Analysis of the Proposed Game22

• Refer to paper for proof of: 1. Existence; and 2. Uniqueness

of the Stackelberg equilibrium

A. Analysis of Cellular Network Level Game:

• Find Lagrangian of the cellular network optimization problem

• Find derivative of the Lagrangian w.r.t. the electricity quantity

and equate it to zero



4. Analysis of the Proposed Game Cont.23

B. Analysis of Smart Grid Level Game:

Solve for

Iteration Step size

=



Outline

1. Introduction

2. System Model




24

6. Conclusion



5. Simulation Results & Discussions25



5. Simulation Results & Discussions Cont.26









Outline

1. Introduction

2. System Model




29

6. Conclusion



6. Conclusion30

• How the cellular network dynamic operation based on traffic

arrival rate, electricity real-time price, and pollutant levels of

retailers can reduce the operational expenditure and pollution

level

• CoMP is used to extend BSs coverage area and reduce

blocking probability for the off-cells

• Stackelberg game formulation

Documents

Green Wireless Cellular Networks Powered by the Smart Grid