A Seminar on

Evaluation of the Efficacy of Forward Error Correction Coding

ByB.Divya

(09B91A0511)

AGENDA

1. Abstract2. Introduction 3. System architecture4. Existing system5. proposed system6. Modules7. Modules Description8. Advantages9. Experimental Setup10. Conclusion11. References

ABSTRACT

We propose a model-based analytic approach for evaluating the overall efficacy of

FEC coding combined with interleaving in combating packet losses in IP networks.

The loss of various packets during the data transmission can be reduced by using

FEC coding.

In this , we are going to evaluate the efficacy of FEC coding. Particularly modeling

the network path in terms of a single bottleneck node.

We develop a recursive procedure for the exact evaluation of the packet-loss

statistics for general arrival processes, based on a framework.

We study both single-session and multiple-session scenarios, and provide a simple

algorithm for the more complicated multiple-session scenario.

INTRODUCTION

THE packet transport service provided by representative packet-switched

networks, including IP networks, is not reliable and the quality-of-service (QoS)

cannot be guaranteed.

Packets may be lost due to buffer overflow in switching nodes, be discarded due to

excessive bit errors and failure to pass the cyclic redundancy check (CRC) at the

link layer,.

Forward error correction (FEC) coding has often been proposed for end-to-end

recovery from such packet losses.

However, the use of FEC in this application provides a double-edged sword.

From an end user’s perspective, FEC can help recover the lost packets in a timely

fashion through the use of redundant packets.

SYSTEM ARCHITECTURE

EXISTING SYSTEM

For analysis purposes the packet-loss process resulting from the single-multiplexer model was assumed to be independent and, consequently, the simulation results provided show that this simplified analysis considerably overestimates the performance of FEC.

In existing system a recursive algorithm to compute the packet-loss statistics (block error density), through which the exact residual packet-loss rate after decoding was computed.

Surprisingly, all numerical results given indicates that the resulting residual packet-loss rates with coding are always greater than without coding, i.e., FEC is ineffective in this application.

The increase in the redundant packets added to the data will increase the performance, but it will also make the data large and it will also lead to increase in data loss.

PROPOSED SYSTEM

We propose a model-based analytic approach for evaluating the overall efficacy of

FEC coding more accurately than any existing system.

We study both single-session and multiple-session scenarios, and we reduce the

complexity in multiple-session scenario.

Our model has great potential in recovering the packet losses caused by

congestion at a bottleneck node of a packet-switched network, provided that the

coding rate and other coding parameters are appropriately chosen.

We show that the unified approach provides an integrated framework for exploring

the tradeoffs between the key coding parameters: specifically, Interleaving depths,

channel coding rates and block lengths.

MODULES OF THE FEC

FEC Encoder

Interleaver

Implementation of the Queue

De-Interleaver

FEC Decoder

Performance Evaluation

MODULE DESCRIPTION

FEC Encoder:

FEC is a system of error control for data transmission, where the sender adds

redundant data to its messages. This allows the receiver to detect and correct errors

(within some bounds) without the need to ask the sender for additional data. In this

module we add redundant data to the given input data, known as FEC Encoding.

Interleaver:

Interleaving is a way of arranging data in a non-contiguous way in order to

increase performance. It is used in data transmission to protest against burst errors. In

this module we arrange the data (shuffling) to avoid burst errors which is useful to

increase the performance of FEC Encoding.

MODULE DESCRIPTION

FEC Decoder:

In this module we recover the original data after the process of De-

Interleaving by extracting the original data from the lost packets.

Performance Evaluation:

In this module we calculate the overall performance of FEC Coding in

recovering the packet losses.

Implementation of the Queue:

In this module we receive the data from the sender and voluntarily

creating the packet loss in order to evaluate the performance of the FEC. Then we

transfer the data to the receiver.

De-Interleaver:

In this module we rearrange the data back to its original order

before Interleaving. This is known as the process of De-Interleaving

MODULE DESCRIPTION

IMAGES

IMAGES

IMAGES

IMAGES

ADVANTAGES

Forward Error Correction (FEC) enables a system to achieve a high degree of data

reliability, even with the presence of noise in the communications channel.

In systems where improvement using any other means (such as increased transmit

power or components that generate less noise) is very costly or impractical, FEC

can offer significant error control and performance gains.

In systems with satisfactory data integrity, designers may be able to implement

FEC to reduce the costs of the system without affecting the existing performance..

The introduction of the Per FEC line of FEC encoders and decoders makes

powerful FEC implementation a realistic goal for most digital communication and

storage systems. More than ever before, FEC is available for a wide range of

applications.

EXPERIMENTAL SETUP

Hardware:

PROCESSOR : PENTIUM IV 2.6 GHz

RAM : 512 MB

MONITOR : 15”

HARD DISK : 20 GB

CDDRIVE : 52X

KEYBOARD : STANDARD 102 KEYS

MOUSE : 3 BUTTONS

Software:

FRONT END : JAVA, SWING

TOOLS USED : JFRAME BUILDER

OPERATING SYSTEM: WINDOWS XP

CONCLUSION

FEC has great potential in recovering the packet losses caused by congestion at a

bottleneck node of a packet-switched network.

We developed a model to implement interleaving to improve the FEC performance

and determined how much interleaving depth is required for FEC to approach the

optimum performance.

We derived an upper bound on the end-to-end performance using FEC based on an

information-theoretic methodology, which is useful in predicting source rates that can

be supported with arbitrarily high reliability.