Energy Efficient Spectrum Allocation for Green Radio in Two-tier Cellular Networks

Energy Efficient Spectrum Allocation for Green Radio in Two-tier Cellular Networks

Wenchi Cheng, Hailin Zhang, Liqiang Zhao and Yongzhao Li

Global Telecommunications Conference, 2009. GLOBECOM 2010. IEEE

Reporter : 李後愷

2

Outline

Introduction System model Model for energy consumption in downlink Spectrum allocation for green radio Simulation and results Conclusion

Introduction

Green Radio, which aims to reduce energy consumption of information and communication technologies (ICTs).

Over 80% of the power in mobile communications is consumed in the radio access network, especially cost in base stations.

Actually, there are already a lot of energy efficient strategies in cellular access networks. However, these strategies mainly focus on smart ends with uplink energy constrains.

3

System model

4

System model

5

System model

6

The mean number of femtocells per cell site is readily obtained as

Users are assumed to be uniformly distributed inside each cell site

System model

Two main different strategies for femtocell access have been proposed so far:

Public Access where all the users can access all the femtocells of a given operator.

Private Access where only the subscriber of the femtocell and a list of invited users can access a given femtocell.

U = Um+NfUf denote the average number of users per cell with Um and Uf referring to the number of outdoor users of per macrocell and indoor users of per femtocell respectively

Green factor: the b/J power efficiency per subchannel.

7

Channel Model and Scheduling Strategy

Three factors have bad effects on signal quality: path loss, shadowing (slow fading), multipath fading (fast fading)

Each BS assigns rate adaptively based on the received SIR per user

We assign:

8

9

Channel Model and Scheduling Strategy

BS & FAP Power Consumption

10

Spectrum allocation for green radio

11

According to recent surveys, over 50 percent of calls and 70 percent of data services will take place indoors in the future.

Spectrum allocation for green radio

12

13

Simulation

14

Simulation

15

Conclusion

Maximizing the green factor under spatial spectral efficiency is an effective way to improve energy efficiency

16

每週一句

Have + pp.

Had + pp.

Past tense

now

17