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Picture ViewerPicture Viewer-- A Mobile ApplicationA Mobile Application

using Network Codingusing Network Coding

Group Member -

Divya

Tejaswini Gaulkar

Project Guide -

Prof. B.W. Balkhande

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INTRODUCTIONINTRODUCTION

y Picture Viewer

A mobile application that can convey

pictures from one source device to many

neighboring devices using WiFi.

y Network Coding

Coding through which we can efficiently

access the network and have the knowledge

about the sent and received packet.

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EXISTING SYSTEMEXISTING SYSTEM

Existing System aims at sending a Picture or Data from one device to

another using Bluetooth, Infrared or MMS.

If a data is needed to be sent to more than one device it needed to

sent again and again.

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PROPOSED SYSTEMPROPOSED SYSTEM

y A Single Source Mobile can send a data to one or moredevices via WiFi network.

y That means it will eliminate the drawback of earlier system of

sending the data no. of times as the no. of recipients.

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PURPOSEPURPOSE

y Earlier System sends data from one source toanother single recipient. If we want to send adata to a bigger number of devices the onlything we could do is to either repeat the processagain and again or share it on some socialnetwork site.

y To avoid such a scenario we aim at developing asoftware that could efficiently establishcommunication network between two or moredevices.

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Transmission ApproachesTransmission Approaches

y We assume that a single source s broadcast data to Nsinks t1... tN and that the source has a direct wireless

link to the sinks.

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y The different approaches for transmitting the

packet are-

Unicast

Broadcast

Pure Network Coding

Systematic Network Coding

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UnicastUnicast

y Fully reliable as each sink is served individually

y Advantages:

- Simple to implement

- Low computational complexity

y Disadvantages:

- Time consuming when number of sinks

increases- Energy consumption coupled with time

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BroadcastBroadcast

y Highly efficient approach as long as no error

occurs on wireless link

y Introduces need for feedback information for

lost packetsy Performance depends on effectiveness of

Medium Access Control(MAC)

y Faster than unicast if N>1

y Performance is less sensitive towards number of

sinks

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Pure Network CodingPure Network Coding

y Random Linear Network Coding (

RLNC).

y Simplify problem of correcting lost packets at the

sinks and reduces requirement for feedback from

sinks.

y In network coding nodes can combine information tocreate new packets.

y Source codes n + r packets from the n original

packets and broadcasts these packets.

r= number of redundant packets

n= linear independent packets, which can then be

decoded to recreate the original packets.

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Systematic Network CodingSystematic Network Coding

y

To decrease the complexity systematic networkcoding can be used.

y Systematic network coding combines the broadcast

and network coding approaches.

y As there is no obvious gain in coding the first n

packets, the source broadcasts these packets and codethe remaining r packets.

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ExampleExample

y

Consider if mobile devices 1, 2, and 3 have lostpacket 17, 21, and 16 respectively.

y Broadcast-

Three broadcast packets must be transmitted.

Each retransmitted packet is only useful for a single

source, while initial packet transmission is useful for

all sinks.

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y Pure Network Coding-

Source could code packets 16, 17, and 21 togetherinto new packet of the same length as original packets.

This packet is broadcasted to three sinks, which each

remove from coded packet, the packets they already got

and thus decode the packet into packet they lost.

y Systematic Network Coding-

Each uncoded packet is useful for all N sinks as theyare linear independent. The following r packets are coded

and have a high probability of being independent of the n

uncoded packets.

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Comparison of the differentComparison of the different

approachesapproaches

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CODING ALGORITHMCODING ALGORITHM

y The data to be transferred from source to the sinks isdivided into packets of length m.

y The n original data packets of length m is arranged in

the matrix

M=[m1m2mn] where mi is a columnvector.

y Encoding-- For pure network coding, M is multiplied with a randomly

generated vector g of length n to get one coded data packet,x = M x g. In this way we can construct X = [x1x2 ... xn +r ]that consists of n + r coded data packets and G = [g1g2 ...gn+r] that contains n + r randomly generated encodingvectors.

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For Systematic Network Coding, we can generate

an uncoded packets Y from its trivial encoding

vector h, Y= M x h. In this way we can construct

Y=[Y1Y2 Yn] that consists of n uncoded data

packets and H =[h1h2 hn ] that contains the n

independent trivial encoding vectors. Furthermore

we construct X = [x1x2 ... xr ] that consists of r

coded data packet and G =[g1g2 ... gr] that contains r

randomly generated encoding vectors.

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y Decoding at sink

For pure Network Coding, all received codedpackets, xi, are placed in the matrix X= [x1x2 ... xn]and all encoding vectors, gi are placed in the matrixG= [g1g2 gn].The original data M can then bedecoded as M = X x G-l .

For Systematic Network Coding, n receiveduncoded Yi and coded Xi packets are placed in thematrix [YX] = [Y1Y2 Y(n-i) X1 X2 ... Xi] and the ncorresponding encoding vectors are placed in thematrix [HG] = [h1h2... h(n-i) g1g2 gi]. The originaldata M can then be decoded as M= [YX] X [HG]-l.

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Pure Network Coding

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Systematic Network Coding

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y Technology Requirement

Java

C++ for Network Coding and

Symbian SDK Symbian C++

y

Hardware Requirement A Mobile Phone with Symbian OS

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CONCLUSIONCONCLUSION

y We have thus introduced a mobile application calledPictureViewer that via network coding enables a userto share content with several other users.

y

The application itself is simple but it demonstratesthat network coding does not necessarily result in highcomplexity or overwhelming energy consumption.

y The implemented algorithms are designed to allow for

high coding throughput.

y This was achieved by using a binary Galois Field anda systematic random code.

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ThankYou!!!!