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CDMA ANDCDMA ANDBLUETOOTHBLUETOOTH

TECHNOLOGYTECHNOLOGYDone byDone by

JINATA KUMARI ROUTJINATA KUMARI ROUT

COMP.SC.&ENGG.COMP.SC.&ENGG.

PARALA MAHARAJA ENGINEERING COLLEGEPARALA MAHARAJA ENGINEERING COLLEGE

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CONTENTS:CONTENTS:

CDMA INTRODUCTION

ABOUT CDMA

ADVANTAGES

BLUETOOTH TECHNOLOGY INTRODUCTION

FEATURES

SECURITY

BLUE JACKING

BLUE BUGGING

CAR WHISPERER

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CDMACDMA

INTRODUCTION CDMA stands for code division multiple access. Both data and voice are separated from signals using codes then transmitted using a wide range of frequency. Because of

this there are more space left for data transfer (this is the one of the reason why CDMA is the preferred technology for the 3G generation, which is broadband access and theuse of big multimedia messages. 14% of the world wide market goes to CDMA for the 3G generation CDMA uses 1XEV-DO ad EV-DV. It has a lot of user in Asia.

ABOUT CDMA

The mobile industry in India is

divided between the two technologies

GSM and CDMA. While the earlier

service provider had adopted the GSM

technology, The new players have been

using CDMA technology and have

notched up a significant share of the

Indian market.

The Code Division Multiple Access represent different systems of sharing of the radio spectrum for communication.

Normally, the radio spectrum can be shared by different users accessing the same frequency band without causing interference.

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CONTINUEDCONTINUEDThe technique used for this are TDMA (Time Division Multiple Access), FDMA

(Frequency Division Multiple Access) and CDMA (Code Division Multiple

Access).

The FDMA part involves the division of frequency of the (max) 25MHzbandwidth into 124 carrier frequencies spaced 200KHz apart. Each of these

Carrier frequencies is then divided in time, using a TDMA scheme.

The fundamental unit of time in this TDMA scheme is called a burst period and

It lasts 15/26 ms (or approximately .577ms).

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CONTINUEDCONTINUED8 burst periods are grouped into a TDMA frame (120/26 ms, or approximately 4.615ms),

which forms the basic unit for the definition of logical channels. One physical channelis one burst period per TDMA frame.

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CDMA is a form of multiplexing (access to the same resource will be given to

more than one user), which allows the use of a particular frequency for a number

of signals, optimizing the use of available bandwidth.

It is a cellular technology that uses spread-spectrum technique. In CDMA

technology every channel uses the full available spectrum. Individual conversionsare encoded with a pseudo-random digital sequence.

CDMA employs analog to digital conversation (ADC) in combination with spread-

spectrum technology. Audio input is first digitized (ADC) into binary elements.

The frequency of the transmitted signal is then made to vary according to a

defined pattern (code) ,so it can be intercepted only by a receiver whole

frequency response is programmed with

the same code, so it follows exactly along

with the transmitter frequency.

There are trillions of possible

frequency-sequencing codes; this enhances

privacy and makes cloning difficult. The

technology is used in ultra high frequency

(UHF) cellular telephone systems in

the 800 MHz and 1.9GHz bands.

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CDMA is first used during world war II by the English allies to foil German attempts at

jamming transmissions. The allies decided to transmit over several frequencies ,instead

of one making it difficult for the Germans to pick up the complete signal.

ADVANTAGES1)CDMA has a very clear advantage of incase of bandwidth is the major problem in themodern times. The number of channels (users) that can be allocated in a given

bandwidth is higher in CDMA.

2)The cost of setting up a CDMA network is also less.

Due to these advantages there is a high probability that CDMA technology will dominatethe future of mobile communication.

EVALUATIONThe technology is normally evaluated on the following 3 parameters namely the data

transmission capacity, security and radiation levels.

Following table indicates the data transmission .Cellular technology Generation Data transmission

capacity

CDMA (IS-95B) 2.5GB 64kps-140kps

CDMA 2000 3G 2MBps

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AS already explained CDMA uses a radically

different approach. It assigns a unique code

to put multiple users on the same wideband

channel at the same time.

The codes so called pseudo-random code

sequence is used by both the mobile station(handset) and the base station to distinguish

between conversations. This gives a greater

level of privacy and security to the communication.

As far as radiation level concerned, CDMA is the

most harmless one among all existingtechnologies. Of course it transmits microwaves

while on standby mode like other technologies do.

CDMA technology checks 800 times per second its transmission level. CDMA

system

transmits signals only when the user starts conversation. Simply saying, when

you are listening the other ends conversation. You are not affected by microwaveas the speaking person does. It appears that CDMA would be dominating

technology in future and mobile forensics has to gear itself to the requirements of

the CDMA technology.

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TECHNOLOGYTECHNOLOGY

INTRODUCTIONBluetooth is a wireless technology that enables any electricaldevice to wirelessly communicate in the range of 2.5GHz ISMfrequency band. Mobile phones, headsets, PDAs and portablecomputers can communicate and set data to each other withoutwires and cables to link to devices together. The name of Bluetoothderived from the name of an English king Harold Bluetooth.It is a low cost, low power, radio

technology, which is particularly

suited to the short range

personal area network

(PAN) application. Bluetooth speedinterest groups authorized to develop

its specification and license.

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FEATURESFEATURES The main features of BT are given below. It and operates in the 2.4GHz frequency band without having a

license for wireless communication. Up to 10-100 meters data can be transferred in real time.

Close proximity and accuracy is not

required for Bluetooth as in case of infrared data (IrDA)communication

device. Bluetooth doesnt suffer from

interference from obstacles such as

walls while infrared suffers due to obstacles. Bluetooth supports both point to point and

point to multipoint wireless connections

without cables between mobile phones

and personal computers. Data transfer rate of Bluetooth varies 4m

versions to version. Data rate of 1mbps for

version 1.2 up to 3 mbps for version 2.0.

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FEATURES CONTINUED.FEATURES CONTINUED.Then major parts of Bluetooth system are radiofrequency transceiver, baseband, and

protocol stack. Bluetooth is used for small area networking without user intervention.Due to extremely low transmission power in Bluetooth technique battery power issaved. It is a networking standard that works at two levels.

Physical level

Protocol level

Due to these levels mobiles have to agree on these levels when bits are sent. It

decides the amount of data to be sent at a time, and how the parties in a conversationcan be sure that the message received is the same as the message sent.

Bluetooth networking transmits data through low power radio waves. It can connect upto 8 devices simultaneously with in the range of about 10 meters. You must think thatthe devices will not interfere with each other.

Bluetooth solved the problem of device interference while sending the data by using

the technique of spread-spectrum frequency. Hopping due to which devices maytransfer data at same frequency at the same time.

The question rises here how Bluetooth send the data using same frequency band

without devices interferences?

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FEATURES CONTINUEDFEATURES CONTINUEDIn Bluetooth technique, transmitters change frequencies 1600 times I every

second. In this way devices can make full use of a limited band of the radiospectrum.

When Bluetooth devices come into the range of each other, conversations take

place

automatically, this conversation automatically determines weather they havethe data to share or not.

In this way Bluetooth devices not only share the data but also control the data

to be transferred. When the connection is established, the devices either they

are part of a computer system or a network, Bluetooth systems create a

personal area network.

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FEATURES CONTINUEDFEATURES CONTINUED

The technology used in Bluetooth also provides security in 3 ways.

Pseudo-random frequency hopping

Authentication

Encryption

Frequency hops make it difficult for anyone to eavesdrop. Authentication allows a user

to limit connectivity to specified devices.

Encryption uses secrete keys to make data intelligence only to authorized parties,

service level security and device level security work together to protect Bluetooth

devices from unauthorized data transmission.

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SECURITYSECURITY

Many serious problems create only due to improper security issues. Some ofthem are given below.

Blue Jacking

Blue Bugging

Car Whisperer

BLUE JACKINGIt is used to send a business card in the form of text messages via

Bluetooth to other users. It should be noted that the distance between

two users is not more than 10 meters. If the user doesnt found the

proper text, he should add the contact to his phonebook.

After saving his contact in his address book retry to send the same

message. In this way the user can get business card from other user

via Bluetooth. Its all because of the known destination from where the

message is being coming.

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BLUE BUGGINGBLUE BUGGING

Due to this hackers can access users phone.

It not only access ones mobile phone, but also use its features including

placing call, messaging, even though the user doesnt realize its happening.

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CAR WHISPERERCAR WHISPERER

It is a type of software due to which hackers can send and receive audio file

from a Bluetooth enabled car stereo.