FITSUM MERGIA

8/13/2019 FITSUM MERGIA

1/15

Smart phone power usage optimization for the caseof Addis Ababa 3G network

ByFitsum Mergia

AdvisorTizazu

A Thesis proposal Submitted to Ato Tizazu in Partial Fulfillment of the Requirements for

the course Research methodologyJanuary 10, 2014

Addis AbabaEthiopia

AAiTAddis Ababa Institute of Technology

Addis Ababa University


2/15

2 | PROPOSAL: Smart phone power usage optimization for the case of Addis Ababa 3G network

Contents

Introduction ............................................................................................................................................... 5

Statement of the problem .................................................................................................................... 6

Scope of the work ................................................................................................................................... 7

Objective of the present work ............................................................................................................. 7

General objective ............................................................................................................................... 7

Specific objective ................................................................................................................................ 7

Methodology ............................................................................................................................................ 7

Literature review ....................................................................................................................................... 8

Work Schedule ........................................................................................................................................ 11

Required budget ................................................................................................................................... 12

Works Cited ............................................................................................................................................. 13

Proposal Submission format ................................................................................................................ 14


3/15


4/15


List of Figures

Figure : 1 RRC Connection states ................................................................................................... 10Figure: 2 Work Schedule ................................................................................................................... 11

List of Tables

Table: 1 required budget ..................................................................................................................... 12


5/15


Introduction

The advent of 3G mobile technologies in Ethiopia provides a wide range of

alternatives for mobile data users. And now a day 3G has become the

connection option of choice in a lot of instances. Even for the areas where 2G

network quality is poor 3G has become the first choice of the subscriber for

Voice service. Yet there is quality of service issues that needs to be addressed in

the course of network optimization. And in this research I will focus on one of the

QoS issue that ethio telecom is currently working on to improve the smartphone

users experience on 3G network. Beginning from year 2012 ethio telecom has

received many complaints from smartphone users regarding their short battery

life while using 3G data services. And until recently the extent of the problem

was not well understood among the optimization engineers of the company.

There have been lots of researches [1] [2] [3] [4] [5] [6] [7] on optimizing the

power usage of smartphone and most of the researches point out that the 3G

radio communication is a significant contributor to battery drain on

smartphones [3] [6] [2].That being the case the root cause for this significant

radio energy consumption is mainly due to the energy wasted during a special

interval ,known as the tail time [3] .The tail time refers to the time interval after a

packet transmission is completed. Since re-establishing a radio connection after

releasing the radio resource incurs a long delay and a high signaling overhead,

radio connection between the UE (User equipment) and the network is

maintained in the tail time, expecting that a subsequent transmission is very likely

to happen in the tail time [3] . However, a large amount of radio energy wouldbe wasted if the expected transmission does not occur in the tail time [3] .

In UMTS 3G networks, multiple timers are used to control the radio resource [7]

.And if the timeout value for releasing the resource is not configured based on


6/15


the data transmission pattern it will results in prolonged tail time which in turn

leads to unnecessary radio energy consumption.

So in this research the statistical data transmission pattern on the existing ethio

telecom 3G network would be modeled based on empirical data obtainedfrom network performance statistics. Afterwards network parameter optimization

would be done on selected network timers in such a way that the smartphone

power usage is minimized.

Statement of the problem

In 3G network, the timers that control when the radio resources have to be

release must be configured based on the actual data transmission pattern. And

the actual data transmission patter has its own dynamics since the pattern very

much depend s on the users data usage experience. Hence the timers value

should track the dynamics in the data transmission. Otherwise there would be

unnecessary energy consumption in the smartphones or cell phones in general.

Specifically, there are two challenges when doing an optimization on these timers.

First and for most this research is bounded within the frame work of the industrialstandards and protocols that are already in place. So any change introduced to

improve the smartphones power consumption must not affect any other network

policies.

If the values for this timer are made very short the smartphones batter life would

be improved very much but it has its own downside. As we reduce the timers

value there would be frequent breaking and making of signaling connection

between the smartphones and the network and this by itself put signaling

processing overhead on the network side and also there would be delay in the

data transmissions which in turn create bad customer experience.


7/15


8/15


9/15


and from country to country and it has statistical signature that can be used for

optimization .

To see the big picture in to which this research fit in, it is essential to have recap

on 3G WCDMA radio network technology with special focus on the radioresource protocol.

Wideband CDMA (WCDMA) is one of the third-generation (3G) wireless

standards that evolve through time under the standardization group of 3GPP.

The 3GPP is an organization that develops specifications for a 3G system based

on the UTRA radio interface and on the enhanced GSM core network. The UTRA

system encompasses two modes: frequency division duplex (FDD) and time

division duplex (TDD). In the FDD mode the uplink and downlink use separate

frequency bands. These carriers have bandwidth of 5MHz. Each carrier is

divided in to 10 ms radio frames, and each frame further divided into 15 time

slots .The UTRAN chip 1 rate is 3.84 Mcps. Every second, 3.84 million chips are sent

over the radio interface. However, the number of data bits transmitted during

the same time period is much smaller. The ratio between the chip rate and the

data bit rate is called the spreading factor ( J. Korhonen, 2003, p.14).

There are four primary RRC (Radio Resource control) states in a 3G network:

Idle, Cell_PCH , Cell_FACH and Cell_DCH. Of these four states ,the last three

states indicate various level of being connected to the network .When a device

is connected to the network it is generally consuming at least some network

resources. The RRC state has an impact on the battery life with some states

requiring considerable more current consumption than other states. There are

also three inactivity timers that are used to determine when a handset or

smartphones should move to a lower state following a specified period of

inactivity. The T1 timer refers to the period of inactivity within the cell_DCH state

1 A chip is a bit in a code word, which is used to modulate the information signal .Since they represent noinformation by themselves, they are called chips rather than bits


10/15


before the 3G device is sent to a lower state. The T2 timer is associated with the

Cell_FACH state and it is used in a similar fashion for determining how long the

3G device should remain in the cell_FACH state without any activity .Finally, the

T3 timer determines how long the handset should remain in cell_PCH before

returning to the idle state. (Signal Research group, 2010, p.12)

Figure : 1 RRC Connection states

Regarding the problem of smartphones battery drain while using 3G data

service, many researches [1] [2] [3] [5] [7] [8] have been made to seek more

efficient solution. By way of example we can consider one novel approach

proposed by three researchers , B.Zhao , Q.Zheng ,G.Cao , from Pennsylvania

state university [7] . Basically this approach made a predication on user

webpage reading time and based on this predication it will let the smartphones

to switch to low power state when the reading time is longer than a threshold

[7] . One downside for this approach is that it put additional computation

overhead to smartphones .But still the experimental result of this approach is

promising [7] .

In a like manner the other research paper [1] selected for review also introduce

another approach which is somewhat static. In this approach the researchers


11/15


tries to model the power consumption of 3G radio link based on several

measurement results and based on this model the researchers made parameter

selection for 3GPP transition state machine .But regarding its scope the research

only consider data transmission with constant bit rate which of Couse will not be

the typical case scenario for WCDMA network. So to this end the approach is

not generic.

In summary, this literature review section highlights the following two key points in

regard to conservation of power in smartphones. The first key point is regarding

the tradeoff that exists between the network signaling load and the smartphone

battery life. And the other key point is regarding the two typical approaches

that researchers used to reduce the smartphone power usage while keeping

the delay of data transmission within reasonable range.

Work Schedule

Figure: 2 Work Schedule


12/15


Required budget

Category Type of Currency Unit Quantity Unit price Total In Eth. Birr

1 Stationery 1.1 Cartridge paper BIRR pcs 4000 0.3 1200 1.2 Correction fluid BIRR pcs 2 10 20 1.3 Eraser BIRR pcs 4 5 20 1.4 File folder BIRR pcs 10 10 100 1.5 Highlighter BIRR pcs 10 15 150 1.6 Notebook BIRR pcs 5 10 50 1.7 Marker pen BIRR pcs 5 10 50 1.8 Pen BIRR pcs 10 5 50

1.9 pencil BIRR pcs 10 3 30 2 Software/Computer 2.1 MapInfo BIRR Licens

1 2,000 2000

2.2 Laptop Computer with highcapacity

BIRR pcs 1 15,000 15000

Total 18605

Table: 1 required budget


13/15


14/15


Proposal Submission format

Submitted by:

Fitsum Mergia Aknaw __________________ ___________________

Student Signature Date

Approved by:

1. Tizazu __________________ ___________________

Advisor Signature Date

2. ___________________ _________________ ___________________

Chairman , Dept.s Signature Date

Graduate Committee

3. ____________________ _________________ ___________________

Chairman, Facultys Signature Date

Graduate Committee

4. ____________________ _________________ _________________

Dean, Graduate school Signature Date


15/15

Documents

FITSUM MERGIA