root/ossiedev/branches/hvolos/docs/ChannelLab/ChannelLab.tex @ 9406

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\title{OSSIE Lab \#: Using the Channel component}
\author{Haris I. Volos, \textit{et al}\\
Virginia Tech, Blacksburg, VA\\
Developed using OSSIE 0.7.x\\
}
\date{June 2009}

\begin{document}

\maketitle

\section{Acknowledgments}
This work was supported in part by NSF award \#0520418, and would not be possible without
the contributions of numerous students on the OSSIE team and other OSSIE users and
developers.

\section{Objective}
The objective of this lab is to familiarize the user with the Channel component

\section{Version}
This lab is for use with OSSIE version 0.7.x, the OSSIE Eclipse Feature (OEF), and ALF running on a computer or VMware image that uses Fedora Core 7 or Ubuntu 8.04. The TxDemo, Channel and RxDemo components are required.

\section{Procedure}
\subsection{Procedure Overview}
\begin{enumerate}
 \item Using OEF, build the ChannelEval waveform with the TxDemo, Channel, and RxDemo components
 \item Run nodeBooter
 \item Run the waveform using different settings and observe the effect on the number of errors
\end{enumerate}

\subsection{Getting Started}
\subsection{Building the waveform}
Using OEF build the ChannelEval waveform with the structure shown in \osref{waveformOEF}. In addition, \osref{blockdiagram} provides an alternative view of the waveform. Only the Channel component has configurable properties, set those properties according to \osref{wfmproperties}
\osfig{waveformOEF}{OEF Waveform Structure}
\osfig{blockdiagram}{Block Diagram}
\osfig{wfmproperties}{Initial Channel Component Properties}
\subsection{Theory}
The TxDemo transmits QPSK symbols with energy $7000^2+7000^2=98000000$ (both I and Q components have an amplitude of 7000).
SNR Estimation in dB is given by:
\begin{equation}
SNR=10log(\frac{RxPower}{Noise})
\end{equation}
AWGN BER Estimation (QPSK)
\begin{equation}
P_b=Q(\sqrt{\frac{E_s}{N_0}})=Q(\sqrt{SNR})
\end{equation}
\subsection{No fading}
Set the fading parameter to ``None''
\subsubsection{Very Low SNR}
Set the noise power to 98000000, which is equal to power of energy of the QPSK pulse generated by the TxDemo component. The resulting SNR is 0 dB.
\osfig{IQ0dB}{I-Q Diagram, 0 dB SNR}

Sample NodeBooter output:
\begin{lstlisting}[]
...
RxDemo errors: 171 / 1024
RxDemo errors: 158 / 1024
RxDemo errors: 155 / 1024
RxDemo errors: 160 / 1024
RxDemo errors: 168 / 1024
RxDemo errors: 175 / 1024
...
\end{lstlisting}
The average bit error equals 0.16 which is very close the theoretical bit error of 0.1587.
\subsubsection{Low SNR}
Set noise power to 9800000
\osfig{IQ10dB}{I-Q Diagram, 10 dB SNR}
Sample NodeBooter output:
\begin{lstlisting}[]
...
RxDemo errors: 1 / 1024
RxDemo errors: 1 / 1024
RxDemo errors: 1 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 1 / 1024
RxDemo errors: 0 / 1024
...
\end{lstlisting}
The Average bit error equals $7.5\times 10^{-4}$ which is also close to the theoretical bit error of $7.83\times 10^{-4}$


\subsubsection{Medium SNR}
Set noise power to 980000
\osfig{IQ20dB}{I-Q Diagram, 20 dB SNR}
Sample NodeBooter output:
\begin{lstlisting}[]
...
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
...
\end{lstlisting}

The average bit error is to low to be estimated, the theoretical bit error is $7.67\times 10^{-24}$.

\subsection{Fading}
Set the fading parameter to ``Ricean'' and the ``Max. Doppler rate'' to 0.001. The theoretical bit error rate is not provided because is not as straightforward to estimate for the the conditions tested as the AWGN case.
\subsubsection{Rayleigh Fading}
Set the ``K fading factor'' to 0 (Rayleigh fading)
It may be observed it the \osref{IQK0EnvelopeFalse} that both the amplitude and the phase of the received signal fluctuates.
\osfig{IQK0EnvelopeFalse}{I-Q Diagram, SNR=20 dB, K=0}
\begin{lstlisting}[]
...
RxDemo errors: 258 / 1024
RxDemo errors: 313 / 1024
RxDemo errors: 346 / 1024
RxDemo errors: 756 / 1024
RxDemo errors: 124 / 1024
RxDemo errors: 595 / 1024
RxDemo errors: 263 / 1024
RxDemo errors: 540 / 1024
RxDemo errors: 148 / 1024
RxDemo errors: 279 / 1024
...
\end{lstlisting}
The average bit error equals to 0.353. 
\subsubsection{Rayleigh Fading - Envelope Fading Only}
Set the ``K fading factor'' to 0 (Rayleigh fading)
Set the ``Envelope Fading Only'' to True

It may be observed it the \osref{IQK0EnvelopeTrue} that only the amplitude of received signal fluctuates, there is not phase fluctuation.
\osfig{IQK0EnvelopeTrue}{I-Q Diagram, SNR=20 dB, K=0, Envelope Fading Only}
\begin{lstlisting}[]
...
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 48 / 1024
RxDemo errors: 2 / 1024
RxDemo errors: 20 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
...
\end{lstlisting}
Average bit error=$6.84\times 10^{-3}$
\subsubsection{Ricean Fading}
Set the ``K fading factor'' to 10
Set the ``Envelope Fading Only'' to False
It may be observed it the \osref{IQK10EnvelopeFalse} that both the amplitude and the phase of the received signal fluctuates less severely compared to the K=0 case.
\osfig{IQK10EnvelopeFalse}{I-Q Diagram, SNR=20 dB, K=10}

\begin{lstlisting}[]
...
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
RxDemo errors: 0 / 1024
...
\end{lstlisting}
Average bit error, to low to be estimated 



\end{document}