voip using wifi p2p

8/10/2019 VoIP Using WiFi P2P

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Seminar

On

Voice over IP Mobile Telephony

Using Wi-Fi P2Pachelor of Technology

in

Information Technology

Under the Guidance of

Mr. Chandrakanta Badajena

Faculty, IT

Submitted By

Suman Mohanta

Registration No: 1101106212

COLLEGE OF ENGINEERING AND TECHNOLOGY

BIJU PATANAIK UNIVERSITY OF TECHNOLOGYBHUBANESWAR, ODISHA


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Certificate

This is to certify that the seminar entitled

Voice over IPMobile Telephony Using Wi-Fi P2P being submitted by

Suman Mohanta bearing Registration No. : 1101106212 in partial

fulfilment of the requirement for the award of the degree of Bachelor

of Technology in Information Technology is a bona fide work carried

out at College of Engineering & Technology under my Supervision.

GUIDE Seminar Coordinator HOD, IT


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cknowledgement

I would like to express my sincere regards and profound sense of

gratitude to those who have helped us in completing the seminar

successfully. At the very outset, my special and heartfelt thanks to my

supervisor Mr. Chandrakanta Badajena, Faculty, IT for his

precious guidance, assistance and constant supervision to bring this

piece of work into the present form.

I also extend my humble gratitude to Dr. Jibitesh Mishra,

HOD, IT for providing the opportunity to present this seminar in the

college.

(Suman Mohanta)

Regd. No.1101106212


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Declaration

I hereby declared that the matter embodied in this seminar is

original and has not been submitted for the award of any other degree.

(Suman Mohanta)

Regd. No.1101106212


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CONTENTS

1 INTRODUCTION .............................................................................................................. 1

2

VOICE OVER IP................................................................................................................ 3

2.1 Benefits of VoIP .......................................................................................................... 4

2.2 The Obstacles to Voice over IP ................................................................................... 6

2.3 VoIP using Wi-Fi ........................................................................................................ 7

3

PEER TO PEER NETWORK ............................................................................................ 8

3.1

How Does a Peer to Peer Network Work? .................................................................. 9

4

MOBILE CALL USING Wi-Fi TELEPHONY ............................................................... 10

4.1 Modules ..................................................................................................................... 13

4.1.1

Enable Wi-Fi ...................................................................................................... 13

4.1.2

Call ..................................................................................................................... 13

4.1.3

Search ................................................................................................................. 13

4.1.4

Display Number on Screen ................................................................................ 13

4.1.5

Provide GSM option .......................................................................................... 14

4.1.6

Connection ......................................................................................................... 14

4.1.7

Reject Call .......................................................................................................... 14

5

BUILDING THE APPLICATION ................................................................................... 15

5.1

The Server Program .................................................................................................. 15

5.2 The Client Program ................................................................................................... 16

6 MOBILE IP COVERSION ALGORITHM ..................................................................... 17

6.1 Traditional Hashing Algorithm for IP ....................................................................... 17

6.2 Mobile to IP Conversion Algorithm ......................................................................... 17

6.3 IP to Mobile Conversion Algorithm ......................................................................... 19

6.4 Algorithm Test Result ............................................................................................... 21

7 CONCLUSION ................................................................................................................ 23

REFERENCES ................................................................................................................ 24


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LIST OF FIGURES

Figure 2.1 Voice over Internet Protocol .................................................................................... 4

Figure 2.2 Voice over Wi-Fi ...................................................................................................... 7

Figure 3.1 Peer to Peer Network ................................................................................................ 9

Figure 4.1 Using Wi-Fi P2P and AP to establish call between mobile phones in addition to

GSM ....................................................................................................................... 11

Figure 4.2 P2P Ad hoc technique using Wi-Fi between mobile phones and wireless laptops 12

Figure 5.1 A Server Program Running on Netbeans IDE ........................................................ 15

Figure 5.2 A Client Program running on Netbeans IDE .......................................................... 16


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ABSTRACT

Voice telephony over mobile is currently supported at a cost using service provider such as

GSM, or using IP service provider at cheaper cost. The purpose of this research is to

design and implement a telephony program that uses Wi-Fi in P2P (Peer- to-Peer) or

WLAN (Wireless Local Area Network) as a means of communication between mobile

phones at no cost. The system will allow users to search for other individuals within Wi-Fi

range and to establish free P2P voice connections, or to establish virtual connection through

Access Points (AP), as well as giving the option to user to use GSM in the case of no Wi-Fi

connectivity is available. The system will use a novel algorithm to convert mobile number

into IP address and use it as a mean for contacting other mobile over P2P or AP using Wi-

Fi technology. The software will use a correlation between current address books available

in mobile phones to convert phone numbers into IP addresses. The system will allow user

to make voice conversation, sending SMS (Short Message Service) as well as MMS. Inbox

and outbox services, message delivery reports, and message drafts will be used for SMS and

MMS management. The current system will only allow for one call per connection, and

no call waiting, or conference calls. The first step of this research and development is to

resolve the technical issue regarding mapping of the mobile users phone number to a

unique IP address in order to avoid IP collision, centralized control, and user configuration.

In addition, voice call will be supported using Wi-Fi to allow mobile phones to communicate

free of cost to each other through P2P or through AP.


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Voice over IP Mobile Telephony Using Wi-Fi P2P

1

1 INTRODUCTION

The support of telephony services over mobile phone has been used everywhere using

technology such as GSM (Global System for Mobile) and 3rd Generation mobile

telecommunication 3G , but at high cost. On the other hand, IP telephony try to reduce the

cost for supporting this service over mobile phone, but it is facing difficulties since the same

feature is supported on desktop and laptop at lower complexity. The challenge is to provide the

same service over mobile phone at no cost, as it has been described in this paper. Two

approaches are suggested in this paper to meet the objective of having free telephony

services over mobile phones. These are the use of Wi-Fi technology over AP, and Wi-Fi over

P2P (Peer-to-Peer). In addition, a novel algorithm has been invented to tackle the first

fundamental problem of designing Ad hoc and P2P telephony using Wi-Fi, which will not

rely on any central database, and will not require users to register to any service.

This can be achieved through executing an algorithm to map a mobile number to a unique

IP address that can be used to establish P2P connection to any other mobile phone running

the same algorithm. Ad hoc network is an IEEE 802.11 communication network that

establishes contact with multiple stations in a given area network without the use of access

points or server . P2P networks help extending the range of fixed wireless networks and give

rise to flexible architectures to adapt to geography of users, information, and signal

transmission in a locally optimal manner. This mobile telephony software lends itself to be a

completely distributed system in terms of architecture.

Currently, servicing IP addressing in traditional networks are managed by two technologies, the

DNS (Domain Name System), and DHCP (Domain Host Configuration Protocol). DNS

Servers resolve human- friendly domain names to IP addresses for computers and resources on

the Internet globally. DNS keeps website addresses consistent regardless of the physical location

or routing protocol. DHCP helps to make automatic network configuration, IP address

allocation, for network devices. Whenever a new device is connected to the network the device

will request for an IP address from the server, which will allocate the address to the networked

device for a specific time period , where dynamic network addressing is used . The DNS

mechanism cannot be applied to P2P Ad hoc network, and therefore a better solution should be

used such as the one suggested in this paper, which is based on Wi-Fi technology.

The first stage of developing the voice over Wi-Fi IEEE 802.11 (Wireless Fidelity)application dealt with the problem of developing a method that could assign unique IP

addresses to mobile devices on the fly without user interaction and central management .


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However, this was a major challenge since devices in Ad hoc mode do not register with any

central service such as DHCP and DNS. Since the mobile software IP addressing facility lacks

coordination with central database, then IP address allocation and IP conflicts present a major

issue.

The solution to the IP problem was tackled in a very innovative way that did not

compromise the softwares P2P and Ad hoc values. GSM mobile phones come with SIM

(Subscriber Identification Modules) cards that help identify users uniquely in GSM networks,

by mapping SIM numbers to subscribers and unique telephone address of the subscribe. There

is no two phones can have the same number in the same network. However the GSM

approach relies on centralized system of communicationrouting andmanagement. However, the

solution proposed in this paper will only rely on the fact that each user has a unique phone

number. An algorithm was devised to map telephone numbers to IP addresses, consequently

creating a unique IP addresses for P2P devices that wishes to communicate. IPv6 was chosen

because of its vast address space availability which is 2138 IP addresses. IPv6 utilizes 128-bit

addresses versus IPv4 which uses 32-bit addresses.

The telephone number & area code are in the format of 0-9 digits for the area code and 0-9

digits, except for the first number that cannot be given the value 0 comprise off 9,000,000,000

numbers unique numbers. IPv6 which has accommodates for more spaces was a better

candidate than IPv4 which has fewer space and is already being exhausted and already in use

by many traditional and wireless networks.


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2 VOICE OVER IP

Voice over IP (VoIP, or voice over Internet Protocol) commonly refers to the communication

protocols, technologies, methodologies, and transmission techniques involved in the delivery of

voice communications and multimedia sessions over Internet Protocol (IP) networks, such as theInternet. Other terms commonly associated with VoIP are IP telephony, Internet telephony, voice

over broadband (VoBB), broadband telephony, IP communications, and broadband phone.

Internet telephony refers to communications services voice, fax, SMS, or voice-messaging

applications that are transported via the Internet, rather than the public switched telephone

network (PSTN). The steps involved in originating a VoIP telephone call are signalling and media

channel setup, digitization of the analog voice signal, encoding, packetization, and transmission as

Internet Protocol (IP) packets over a packet-switched network. On the receiving side, similar steps

(usually in the reverse order) such as reception of the IP packets, decoding of the packets and

digital-to-analog conversion reproduce the original voice stream. Even though IP Telephony and

VoIP are terms that are used interchangeably, they are actually different. IP telephony has to do

with digital telephony systems that use IP protocols for voice communication, while VoIP is

actually a subset of IP Telephony. VoIP is a technology used by IP telephony as a means of

transporting phone calls. Early providers of voice over IP services offered business models (and

technical solutions) that mirrored the architecture of the legacy telephone network. Second

generation providers, such as Skype have built closed networks for private user bases, offering the

benefit of free calls and convenience, while denying their users the ability to call out to other

networks. This has severely limited the ability of users to mix-and-match third-party hardware and

software. Third generation providers, such as Google Talk have adopted the concept of Federated

VoIP, which is a complete departure from the architecture of the legacy networks. These

solutions typically allow arbitrary and dynamic interconnection between any two domains on the

Internet whenever a user wishes to place a call. VoIP systems employ session control protocols to

control the set-up and tear-down of calls as well as audio codecs which encode speech allowing

transmission over an IP network as digital audio via an audio stream. The choice of codec varies

between different implementations of VoIP depending on application requirements and network

bandwidth; some implementations rely on narrowband and compressed speech, while others

support high fidelity stereo codecs. Some popular codecs include u-law and a-law versions of

G.711, G.722 which is a high-fidelity codec marketed as HD Voice by Polycom, a popular open

source voice codec known as iLBC, a codec that only uses 8 kbit/s each way called G.729, and

many others. VoIP is available on many smartphones and Internet devices so that users of portable

devices that are not phones, may place calls or send SMS text messages over 3G or Wi-Fi.


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Figure 2.1 Voice over Internet Protocol

2.1 Benefits of VoIP

Businesses are rapidly to VoIP because there are compelling advantages.

Firstly, and most obviously, there are significant financial savings on running the network itself.One infrastructure carrying both data and voice, provided by one supplier, can be managed,

maintained and upgraded much more efficiently than two separate networks for voice and data.

Secondly, and more importantly, while each network has its own value, that value is maximised

when the two systems are consolidated. Computer applications and communications technologies

can be intelligently linked to streamline the working environment.

Thirdly, VoIP allows organisations to integrate their telephone, fax, e-mail and other applications

to capitalise on the benefits of unified messaging. Such a system can eradicate unnecessary


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interruptions while ensuring individuals always receive information in the most convenient format

wherever they are in the world.

Fourthly, the system can be used to support flexible working practices, whereby members of staff

work from home or in dispersed, 'virtual' teams. Using the VoIP network, team members can see

when their colleagues are logged on to the LAN or using the telephone. VoIP offers improved

bandwidth capabilities and makes video-conferencing a viable and cost-effective option for

discussions between dispersed team workers.

Fifthly, VoIP technology can contribute to an effective knowledge management strategy. The

larger the organisation, the more information that must be shared, so an efficient communications

system is particularly important. The VoIP network provides individuals with the opportunity to

tap into colleagues' areas of specialism, allowing them to search for experts according to specific

criteria.

Sixthly, an organisation can also use VoIP to enhance relationships with its customers. For

example, converged call centres, or 'IP contact centres', allow agents to answer all customer

enquiry mediums, including telephone, e-mail, fax, web call back, web chat and instant

messaging. Customers appreciate the flexibility of interacting with an organisation that can handle

feedback from a range of different sources, and are even more inclined to do business with those

who can offer an integrated response.

To summarize: VoIP networks provide cheaper means of carrying voice but more importantly

provide a much enhanced range of services. As an OECD paper of December 2001 put it: "The

potential for IP-based voice as a cheaper alternative to traditional telephony is considered to be

less important than the opportunity for the integration of voice in new IP-based applications that

are considered drivers for broadband services".

Increasingly, residential consumers too are taking up the option of VoIP services. For them, such

services offer:

More choice of voice operators and tariff packages

Cheaper services including possibility of 'free' calls

New services such as conferencing

Innovative services to be announced

A compelling reason to subscribe to broadband


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2.2 The Obstacles to Voice over IP

For new entrants, the main obstacle has been the lack of availability of investment capital as a

result of the collapse in the dot com boom and the lack of favour in which the telecommunications

industry has been held by analysts and investors. However, there is now a slow recovery inconfidence and capital availability.

For traditional telcos, the obstacles to investing in VoIP have been the massive sunk costs in

legacy networks, the high initial capital costs in creating new networks, and the lack of

implementation of gateway protocols to allow integration of VoIP with legacy systems. However,

incumbents now face increasing competition from rival carriers and the protocol issues are largely

resolved.

For business customers, in the past, IP telephony has been plagued by doubts over line quality by

end users and concerns about relying on one network (instead of deploying dedicated voice and

data networks). However, these problems are now diminishing, as a result of improved technology

and greater investment in in-house systems. The major remaining problem is the much greater

cost of handsets.

For most domestic customers, VoIP currently means using a pair of lightweight headphones with

a PC to make and receive calls at nil cost even if these calls - as is usually the case - are

international. However, it is already possible to make VoIP calls over a traditional analogue

telephone provided one has a special adaptor connected to an ASDL or cable broadband service.

In future, residential customers will obtain VoIP packaged as a standard item with their broadband

provision.

However, a major unknown is how quickly and how comprehensively broadband will penetrate

the consumer market. In both the UK and the USA, there is evidence of a trailing off in the take-

up of narrowband services at around the 55-60% penetration level so that, even if everynarrowband customer up-graded to broadband, a sizeable proportion of the population could not

avail itself of services like VoIP.

Furthermore, in the residential context, there are a few special problems with VoIP such as

ensuring a secure emergency call service, since VoIP requires mains supply and uses equipment -

such as an adaptor or PC - that may not be wholly reliable. However, since most homes now have

at least one mobile, this may prove not to be a significant deterrent.


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2.3 VoIP using Wi-Fi

VoIP is the technology that allows the transmission of audio files by transmitting them into data

packets across the Internet. By integrating Wireless and VoIP a new generation of audio

telecommunications has been birthed. By having a VoIP service and a wireless connection, youcan enjoy the best of both worlds- wireless VoIP connections. Wireless networks are activated by

what is known as a hotspot. A hotspot is an area where there is an access point. Wireless

connections are basically created by radio signals. An access point is where the network has

established their main signal. It is possible for wireless users to basically jump from hotspot to

hotspot and utilize various networks access points. The combination of Wireless and VoIP has led

to the invention - VoWi-Fi technology. VoWi-Fi stands for Voice over Wireless Fidelity. Many

people are choosing the freedom that is offered by VoIP. VoIP can offer nearly free or free long

distance phone calls.

Figure 2.2 Voice over Wi-Fi

Since VoWi-Fi operates from hotspot to hotspot or network-to-network, you may think that there

are roaming charges involved. There are no roaming charges involved with VoIP. So you can take

your VoWi-Fi phone from hotspot to hotspot, maintaining your connection (provided you easilygo from hotspot to hotspot) absolutely free.


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3 PEER TO PEER NETWORK

Peer-to-peer is a communications model in which each party has the same capabilities and either

party can initiate a communication session. Other models with which it might be contrasted

include theclient/server model and themaster/slave model. In some cases, peer-to-peercommunications is implemented by giving each communication node both server and client

capabilities. In recent usage, peer-to-peer has come to describe applications in which users can use

the Internet to exchange files with each other directly or through a mediating server.

IBM's Advanced Peer-to-Peer Networking (APPN) is an example of a product that supports the

peer-to-peer communication model.

On the Internet, peer-to-peer (referred to as P2P) is a type of transient Internet network that

allows a group of computer users with the same networking program to connect with each other

and directly access files from one another's hard drives.Napster andGnutella are examples of this

kind of peer-to-peer software. Major producers of content, including record companies, have

shown their concern about what they consider illegal sharing of copyrighted content by suing

some P2P users.

Meanwhile, corporations are looking at the advantages of using P2P as a way for employees to

share files without the expense involved in maintaining a centralized server and as a way for

businesses to exchange information with each other directly.
http://searchnetworking.techtarget.com/definition/client-serverhttp://searchnetworking.techtarget.com/definition/master-slavehttp://searchcio.techtarget.com/definition/Napsterhttp://whatis.techtarget.com/definition/Gnutellahttp://whatis.techtarget.com/definition/Gnutellahttp://searchcio.techtarget.com/definition/Napsterhttp://searchnetworking.techtarget.com/definition/master-slavehttp://searchnetworking.techtarget.com/definition/client-server


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Figure 3.1 Peer to Peer Network

3.1 How Does a Peer to Peer Network Work?

The user must first download and execute a peer-to-peer networking program. (Gnutellanet is

currently one of the most popular of these decentralized P2P programs because it allows users to

exchange all types of files.) After launching the program, the user enters the IP address of another

computer belonging to the network. (Typically, the Web page where the user got the download

will list several IP addresses as places to begin). Once the computer finds another network

member on-line, it will connect to that user's connection (who has gotten their IP address from

another user's connection and so on).

Users can choose how many member connections to seek at one time and determine which files

they wish to share or password protect.


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4 MOBILE CALL USING Wi-Fi TELEPHONY

Wi-Fi telephony, also known as Voice over wireless LAN (VoWLAN), delivers the all the

capabilities and functionality of the enterprise telephone system in a mobile handset. The Wi-Fi

phone is a WLAN client device, sharing the same wireless network as laptops and PDAs. Thehandset is functionally equivalent to a wired desk phone, giving end-users all the features they are

used to having in a wired office phone. The benefits of VoWLAN can result in substantial cost

savings over other wireless technologies by leveraging the Wi-Fi infrastructure and by eliminating

recurring charges associated with the use of public cellular networks. For end users, VoWLAN

enables employee mobility, resulting in increased responsiveness and productivity.

Wi-Fi telephony is the upcoming technology that can be set up on existing enterprise Wi-Fi

network and empowers enterprises with voice mobility benefits in an easy, scalable and cost-

effective way. Increased deployment of superior Wi-Fi networks to achieve wireless data access

and increased adoption of VoIP technologies to make cost-effective calls has led the concept of

Wi-Fi telephony to emerge in the recent years. With Wi-Fi telephony in place, voice mobility can

be achieved in an easy to use and inexpensive way. Voice mobility in general refers to flexibility

for users to make telephone calls from any place within a premise. Enterprise premises

empowered with voice mobility have more productive employees, increased employee

convenience and improved business process resulting in faster decision making, increasedresponsiveness and greater overall productivity and efficiency.

First, as described in the previous section, using Wi-Fi technology will allow mobile phones to

communicate to each other at no cost compare to GSM technology where high charge is applied.

In order to support voice call over mobile phones using Wi-Fi seamlessly without affecting the

user normal behavior in making a call to any mobile phone, a new novel technique has been

invented in this paper as described in Figure 4.1.


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Check if

IPM2

connected

to IPAP

Yes

No

Yes Yes

NoNo

Yes

No

No

Figure 4.1 Using Wi-Fi P2P and AP to establish call between mobile phones in addition to GSM

In this figure, if mobile user (M1) is willing to make a call to other mobile user (M2), the

invented algorithm will convert both mobile numbers to 2 unique IP numbers using IPv6. Then

M1 will try to establish a P2P call to M2 using the mapped IP to Mobile ( IPM1, IPM2). If M2

is within the range of Wi-Fi of M1, then a virtual connection will be established between M1

and M2, and then M2 will convert IPM1 to M1and make the ring by showing the calling number

M1 call M2

Can IPM1

have P2P

toIPM2

Is IPM1

connected

to IPAP

M1 pop up msg to

user to use GSM to

call M2

Is answer

Yes

M1 establish virtual

connection to M2

using ( IPM1, IPM2)

At M2 M1=IptToMob

( IPM1)

Ring(display M1)

M1 establish virtual

connection to M2

through AP using

(IPM1, IPM2, IPAP)

M1 establish connection

to m2 through GSM

If accept call M1 will

have conversation

with M2

Deny call

IPM2=MobToIp(M2)

IPM1=MobToI (M1)


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coming from M1. If user of M2 accepts the call, M1 and M2 will be able to communicate to

each other using voice over IP. However, if M2 is far from M1, then M1 will try to see if M2 is

connected to close AP within the same range of M1. If both M1 and M2 are connected through

AP, then M1 and M2 will establish a virtual connection using ( IPM1 , IPAP, IPM2 ). Then if

user of M2 accepts the call, M1 and M2 will be able to communicate to each other using voice

over IP. However, if M1 and M2 are not covered by any Wi-Fi network, a message will be

popped up to user of M1 asking if he/she is willing to continue the call through GSM or other

wireless network. Then the user would have the choice to carry on or cancel the call. As it was

described in the previous section, Wi-Fi would require the mapping of mobile number to a

unique IP address, and vice versa. The algorithm described in this paper would allow the

mapping without the need for storing this mapping since it will convert mobile number to

unique IP and unique IP to mobile number. This algorithm needs to be applied to all mobileswishing to use this technique. It is very clear that the new technique using Wi-Fi would allow

users to make a voice call through mobile phone at no cost.

Figure 4.2 P2P Ad hoc technique using WI-FI between mobile phones and wireless laptops


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WLAN connection using Wi-Fi is during a voice call session to particular IP address. A virtual

circuit is created. A users microphone device becomes a client to the other users spe aker

device and vice-versa. This way there can be simultaneous dialogue.

Figure 4.2 shows the use of Wi-Fi over P2Pconnection between 2 mobile phones as well as 2

wireless laptops to making voice call. This P2P connection is based on unique IP address linked

to the mobile number, where user would be able to call other mobile phone using its mobile

number or through browsing the phone list. In order for this P2P to work using a unique IP

address, the invented algorithm described in this paper has to be executed at both mobiles to

convert mobile number into unique IP address and to do the other conversion from IP to mobile

number needed for displaying the calling number on the mobile phone.

4.1

Modules

A module specifies the functionality of the system. Each Module describes some specific task of

the system. Generally software is made up of the different modules. This project divided into

following modules:

4.1.1 Enable Wi-Fi

When the Wi-Fi supported mobile will come into Wi-Fi region then we have to enable Wi-Fi of

that mobile. At that time IP address is generated from mobile number by using novel algorithm.

That IP address is assigned to that mobile.

4.1.2 Call

When caller dials the number (mobile number of receiver), at that time IP address is generated

from dialled number and the broad cast request for connection.

4.1.3 Search

For connection different searches are used. Initially caller mobile will search receiver mobile is

present in Wi-Fi region directly. If receiver is not found in that region then it will take the help of

AP (access point). With the help of AP the caller mobile will search receiver mobile. If in both

cases receiver mobile is not found then system provides GSM option for connection.

4.1.4 Display Number on Screen

When the receiver mobile is found then at receiver side source number is displayed on the screen

with ring. That source number is generated from source IP address using novel algorithm. Novelalgorithm is used for convert mobile number into IP address and IP address into mobile number.


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4.1.5 Provide GSM option

If receiver mobile is not found within Wi-Fi directly or with the help of AP then this new option is

provided to the caller. This is provided for call as like the way of tradition call. In that call method

charges are applied by GSM services provider. This option is enabled means receiver is not within

the sources Wi-Fi network.

4.1.6 Connection

If receiver mobile is found to caller then number is displayed on the receiver screen then receiver

mobile user has options like accept call or reject call. If he accept the call then the connection will

established between caller and receiver mobile. If that connection within Wi-Fi network then it is

free of cost communication and if it is using GSM service then charges are applied by GSM

service provider.

4.1.7 Reject Call

Reject call means break connection or avoid connection. When phone rings and call is rejected

means connection is not established and when call is rejected while the communication is going

on is the break in connection. Connection can be closed by either side as caller or receiver side.


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5 BUILDING THE APPLICATION

The application can be developed using any programming language that supports Peer to Peer

connection but Java is recommended as it can be implemented on almost every mobile platform

such as Android, J2ME etc. The application contains two major programs which establishconnection between the devices.

5.1 The Server Program

The role of the server is to coordinates all the activities of the clients in such a way that the clients

interact as fast and efficient as possible. The Server should implement a minimal GUI to give

feedback on client activities. The server will accept connections from multiple clients, but multi-

threading is not necessary. When a client terminates its connection, it should be done in a cleanfashion where the server operations are not disrupted. With voice calls, the servers only role is to

check and see if the requested user is still active, and then to initiate the session. All further

communication between the two users are handled by the client programs. Users should also be

able to send text messages and these should be correctly displayed by the receiving clients.

Figure 5.1 A Server Program Running on Netbeans IDE


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5.2 The Client Program

The role of the client is to interface with the user, translate requested operations, and interact with

the server. It is essential for the client to have a GUI, to act as an interface for the user. Clients

may initiate voice calls to other clients by having the user give a call command and a host nameto call to. Voice communications, between clients are direct, without any server interference. The

server should merely act as a proxy and look-up service, assisting clients in making the

connections. Text communications should also be possible. Voice communications should occur

in real-time.

Figure 5.2 A Client Program running on Netbeans IDE


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6 MOBILE IP COVERSION ALGORITHM

A software solution was developed in order to convert mobile numbers to IP addresses and vice

versa. In this program development, it is possible to map the mobile numbers to a valid IPv6

address, and therefore there is no need for DNS lookup. In addition, there is no need forcomplicated hashing and addressing protocols because the IP-to-Mobile algorithm would produce

a unique number used as input, leading to a unique output hexadecimal IPv6 address. The

outputted address is then allocated to private IP within a specified range in order not to conflict

with other devices in the same wireless range.

6.1 Traditional Hashing Algorithm for IP

( )

N is the size of IP range, which should be a prime number larger than our range in order to assure

good performance for the algorithm. Consider every IP address as a quadruple of integers modulo

N which in IP addresses are 32-bit which quadruple 8- bit. We can define function H for hashing

of number mod N, and fix any four coefficients such that

( ) [11]

6.2

Mobile to IP Conversion Algorithm

This algorithm will map any mobile number to a unique IPv6 address,

where X10 is {x |1,000,000,000 x 9,999,999,999) base 10 decimal integer and the function f(x)

converts X base10 to X base 16 Hexadecimal integer with range { x|3B9ACA00

x2540BE3FF}as defined in the pseudo code of MobToIP.

function MobToIp(String number)

//Input: String representation of phone number

//Output: IPv6

String ip"" String hex""

//character array of 16 hexadecimal group of 4 hexadecimal octets, and all initialized to zero and

separated by":"


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ipArray ['0','0','0','0',':',.....,':','0','0','0','0']

/* read mobile number and store it in charArray, where each digit of the mobile number is

represented by one equivalent hex digit. Eg charArray [ ] = readMobNum(9897345112), then

char Array[9,8,9,7,3,4,5,1,1,2] */

char Array[ ] =readMobNum(calledNumber)

/*Initialize Integers counter variables for loop

Integer i0;

Integer k0;

Loop

{

if ipArray[k]=0

{

ipArray[k]=charArray[i]

ii+1

}

if ipArray[k]=":"

{

ipArray[k+1]=charArray[i]

}

kk+1

}

While( i


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hexBufferipArray[c] cc+1

}

iphexBuffer return ip

End function

6.3 IP to Mobile Conversion Algorithm

This algorithm would do the reverse of Mobile-to-IP algorithm to convert unique IPv6 into

mobile number, where X16 is {x|3B9ACA00 x 2540BE3FF} base 16 hexadecimal integer and

the function g(x) converts X base16 from to X base10 decimal integer with range X10 is

{x|1,000,000,000 x 9,999,999,999} as defined in the pseudo code of IpToMob.

function IpToMob(String IP)

/*Input: IPv6

/*Output: String representation of phone number

/*Initialize local String variables to empty Strings

String string1, string2, string3""

String output""

charArray will be set to input ip value charArray ip

/*String buffer object firstBuffer new buffer object

Integer loop counter i0

Loop For i< length of charArray

{

firstBuffercharArray[i] increment ii+1

}

/*reverse order of string buffer elements of firstBuffer

string1 firstBuffer reverse

/*Character Array charArray2 will contain values of string 1


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charArray2 string1

/*loop replace trailing zeros with "*"

Integer loop counter c0

Loop For c


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character array charArray3 string2

Integer loop counter k0

Loop For klength of charArray3

{

if charArray3[k]!='*'

{

string3string3+charArray3[k]

}

}

End for loop

character array charArray4 string3

Integer loop counter a0

Loop For a


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alteration in compilation and versioning. J2ME is robust, scalable, and secure platform for mobile

phones, personal digital assistants, and embedded devices. J2ME contains TCP/IP networking and

GUI APIs along with other packages that will allow reliable development mobile applications.

The utilization of native platform dependent code maybe needed in order to automatically change

IP addresses within the phones operating system without user interaction. At this stage

implementation covers the conversion of mobile number to IPv6 address and the reverse

conversion of IPv6 address into mobile number. A Java program for the conversion from mobile

to IPv6 and from IPv6 to mobile has been done and proven the correctness of the algorithms.

Where, a user would enter the mobile number which will be converted to a unique IPv6. The other

IPv6 to mobile algorithm allows user to enter IPv6 in hex and then it will convert it to mobile

number. In the future a complete program will be developed to establish a P2P connection or a

virtual connection over AP in order to allow the 2 mobile phones to communicate to each otherover Wi-Fi technology at no cost.


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7 CONCLUSION

Voice over Wi-Fi telephony is a challenging research topic. In this paper a novel architecture

has been proposed and a novel algorithm has been developed to support IP to Mobile

number conversion. The system is transparent to the user, where a user needs only to dial the

required phone number the same way of using the normal mobile phone. Following the mobile

conversion to IPv6, the software applied at the mobile phone will try to establish P2P

connection to the dialled mobile phone using the same algorithm.

If no P2P connection can be made, then the calling mobile phone will check if virtual

connection can be possible through AP using the same mechanism in P2P to establish

communication channel with the called mobile phone. If no wireless connection using Wi-Fi is

possible between the 2 mobile phones, then a message would be displayed on the calling mobile

phone notifying its user to proceed with the call using GSM technology or abort the call.

The IP collision problem for mapping mobile to IP has been avoided since there is a unique

mapping resulting in a unique IP for each mobile number. The work presented in this paper is

a first step for developing a P2P voice to voice communication between 2 mobile users using

the Wi-Fi network which is based on 10 mobile digit numbers. Future work will focus of the

development of automated algorithm to develop IP collision avoidance and correction for

large mobile digit numbers.

Furthermore, a complete solution to establish communication channel between 2 mobile phones

using P2P or through AP, and optional GSM will be developed. In addition, the release of the

voice API by the giant mobile manufacturers will enable future complete working system

based on the architecture initiated by this research work.


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REFERENCES

[1] Ghassan Kbar , Wathiq Mansoor , Aryan Naim, Voice OverIP mobile telephony using

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[3] F. Borko, and M. Ilyas, Wireless Internet Handbook Technology, Standards, and

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[12] D. Sanjoy, C. Papadimitriou, and U. Vazirani, Algorithms, 1st. New York: McGraw

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voip using wifi p2p

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