Project 2C(ii) Implementation of OFDM on AWGN Channel

Karira Vishal DKarunakar H V

Prabeedh KumarRavi Kiran

Sreenivas Reddy

Project Architecture

Tasks AssignedPrabeedh kumar and Sreenivas Reddy1.Audio Input file to Data Bits2.Data Bits to Symbol Mapping & Symbol to Data Bits

Mapping

Karunakar and Ravi Kiran1.Implementation of FFT and IFFT

Karira Vishal1.Add and Remove Cyclic Prefix2.AWGN Channel Implementation

DeliveredOFDM matlab code for Single User.C code for Bit to symbol and Symbol to Bit mapping.C code for FFT and IFFT on Cell SDK Simulator.C code for AWGN Channel on Cell SDK simulator.

Problems Faced Integrating the Audio file in Cell SDK Simulator.

Future TasksHandling the multi user inputs. Implementation of OFDMA on an AWGN Channel

Conversion of wave file to bits• I have taken .wav file as input.• After that converted that wav file to text file

which contains binary data

Wave file format:

Conversion of bits to symbols• I have sent that binary into channels• I modulated that data by using BPSK(Binary

Phase Shift Keying)

FFT & IFFT Block Implementation

• IFFT and FFT block is implemented using radix-2 algorithm,using Cooley tukey algorithm.

• Dividing the data in equal proportion and loading it into all 8 SPU using the above algorithm.

• Reference: SDK for Multicore Acceleration ,Programming Tutorial.

• Task of PPU: 1.Intializing the context data for Thread creation.2.Load data for each SPU.

3.Get back the result after the calculation.

FFT & IFFT Block Implementation(contd..)

• Task of SPU1.Getting the data from PPU.2.Initate DMA to/from 32 bit Effective Address.3.Performing the calculation for each SPE loaded

data.4. Perform write operation to and initiate DMA.

Add and Remove Cyclic PrefixCyclic Prefix : A copy of the last part of OFDM

signal is attached to the front of itself.In the Transmitter side, we have added 10%

of the total number of bits and in the Receiver side, we have removed them.

This bits helps us to combat against ISI almost completely.

But it also leads to reduction in the Bandwidth Efficiency.

AWGN channel

AWGN (Additive White Gaussian Noise) channel adds noise to the transmitted bits in order to present a real time effect of noise.

Y = X + Nwhere Y = Received Sequence

X = Transmitted SequenceN = Noise

ReferencesCell BE Architecture and its First Implementation:http://www.ibm.com/developerworks/power/library/pa-

cellperf/Cell BE Example Sites:http://www.ibm.com/developerworks/library/pa-

sdkexamples/index.htmlCell BE Resource Center:http://www.ibm.com/developerworks/power/cell/?

S_TACT=105AGX16&S_CMP=HPMake file help:http://www.cat.pdx.edu/documents/make.htmlPosix Thread:http://www.ibm.com/developerworks/linux/library/l-

posix1.html