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% Document Info
\author{Bayan (Bayan.A)}
\pdfinfo{
  /Title (networks-physical-layer.pdf)
  /Creator (Cheatography)
  /Author (Bayan (Bayan.A))
  /Subject (Networks - Physical Layer Cheat Sheet)
}

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\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
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    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
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\columnbreak
\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Networks - Physical Layer Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{Bayan (Bayan.A)} via \textcolor{DarkBackground}{\uline{cheatography.com/122738/cs/22931/}}}
\end{tabulary}
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\fancyfoot[L]{ \footnotesize
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{LL}
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  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}Bayan (Bayan.A) \\
  \uline{cheatography.com/bayan-a} \\
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 19th July, 2023.\\
   Updated 24th May, 2020.\\
   Page {\thepage} of \pageref{LastPage}.
\end{tabulary}
\vfill
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  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}}  \\
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  \vspace{-5pt}
  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
\end{tabulary}
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\raggedright
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\begin{multicols*}{3}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Nyquist Theorem}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Equation expressing maximum data rate for a finite bandwidth noiseless channel} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
If signal is run through a low-pass filter of bandwidth B & The filtered signal can be completely reconstructed by making only 2B samples per second \tn 
% Row Count 7 (+ 5)
% Row 2
\SetRowColor{LightBackground}
Sampling faster than 2B x per second is pointless & Higher frequency components have already been filtered out. \tn 
% Row Count 10 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{B = channel bandwidth \newline V = discrete levels the signal consists of \newline Max data rate = 2B log₂ V bits/sec}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Twisted Pair}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{A form of transmission media} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
Two insulated copper wires (1mm thick) & Twisted in helical form (like DNA) \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Wires are twisted so the waves cancel out} \tn 
% Row Count 4 (+ 1)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Used for transmitting analog or digital information} \tn 
% Row Count 6 (+ 2)
% Row 4
\SetRowColor{LightBackground}
Bandwidth depends on wire thickness and distance traveled & Several megabits/sec for a few kilometers \tn 
% Row Count 9 (+ 3)
% Row 5
\SetRowColor{white}
Widely used & Adequate performance and cheaper \tn 
% Row Count 11 (+ 2)
% Row 6
\SetRowColor{LightBackground}
{\bf{UTP}} & Unshielded Twisted Pair \tn 
% Row Count 13 (+ 2)
% Row 7
\SetRowColor{white}
Cat 5 UTP cable, mostly in office buildings: & 4 pairs of twisted insulated wires in a single plastic sheath. \tn 
% Row Count 17 (+ 4)
% Row 8
\SetRowColor{LightBackground}
{\bf{Full-Duplex}} & Links can be used in both directions at the same time, like a two-way road \tn 
% Row Count 21 (+ 4)
% Row 9
\SetRowColor{white}
{\bf{Half-Duplex}} & Link can be used in either direction, only one way at a time \tn 
% Row Count 24 (+ 3)
% Row 10
\SetRowColor{LightBackground}
{\bf{Simplex}} & Links that allow traffic in only one direction. \tn 
% Row Count 27 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Digital Modulation}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Process of converting between bits and signals} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{To send digital information, we must devise analog signals to represent bits} \tn 
% Row Count 3 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Baseband Transmission}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Signals occupies frequency from zero up to a maximum} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{The maximum frequency depends on the signaling rate.} \tn 
% Row Count 4 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Clock recovery}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{The process of extracting timing information from a data stream for the receiver to decode} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{To encode bits into symbols, receiver must know when one symbol ends and the next begins} \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Receiver needs to reference a clock of the same frequency} \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
Accurate clocks are expensive & Another strategy must be used \tn 
% Row Count 8 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{{\bf{Overhead Definition}}}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Overhead is any combination of excess or indirect computation time, memory, bandwidth, or other resources that are required to perform a specific task.} \tn 
% Row Count 4 (+ 4)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{NRZ}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Non-return to zero} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Simplest, literal line code} \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
-V for 0 & +V for 1 \tn 
% Row Count 3 (+ 1)
% Row 3
\SetRowColor{white}
A long run of 0's or 1's leaves the signal unchanged & Differentiating between bits become difficult. A long line of 15 0's looks like 16 without a very accurate clock \tn 
% Row Count 9 (+ 6)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{NRZ}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590065184_NRZ.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Bandwidth Efficiency}}  \tn
% Row 0
\SetRowColor{LightBackground}
For NRZ, it moves between + and - levels every 2 bits & Requires bandwidth of at least {\emph{B/2}} when the bit rate is {\emph{B }}bits/sec \tn 
% Row Count 4 (+ 4)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{This limits the speed, as more bandwidth is required to run faster.} \tn 
% Row Count 6 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Using more than two signalling levels, the limited bandwidth can be used for efficiently} \tn 
% Row Count 8 (+ 2)
% Row 3
\SetRowColor{white}
e.g. using 4 voltages, 2 bits can be sent at once, as a single symbol & Effective only if the receiver can distinguish the 4 levels \tn 
% Row Count 12 (+ 4)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{The signal change rate is now half the bit rate, thus reducing the required bandwidth.} \tn 
% Row Count 14 (+ 2)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{The rate the signal changes is the {\bf{symbol rate}}} \tn 
% Row Count 15 (+ 1)
% Row 6
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{the {\bf{bit rate}} is the {\emph{symbol rate multiplied by the number of bits per symbol}}} \tn 
% Row Count 17 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.18988 cm} x{2.78712 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{NRZI}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{The inverted vesion of NRZ} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
transition for 1 & no transition for 0 \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
Used by USB & Universal Serial Bus \tn 
% Row Count 3 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{NRZI Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590065899_NRZi.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Manchester}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Used for classic Ethernet} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
low to high = 0 & high to low = 1 \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Requires twice as much bandwidth as NRZ because of the clock} \tn 
% Row Count 4 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Adds 100\% overhead} \tn 
% Row Count 5 (+ 1)
% Row 4
\SetRowColor{LightBackground}
Guarantees clock recovery and balanced signal because: & -Each bit is modulated in a balanced signal \tn 
% Row Count 8 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Manchester Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590243813_Manchester.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.38896 cm} x{2.58804 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Bipolar Encoding (AKA Alternate Mark Inversion)}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{0 = logical zero}} & Encodes 0's with a zero-signal \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
{\bf{1 = + or -}} & Encodes 1 with positive or negative level \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{In telephone networks, it is know as Alternate Mark Inversion(AMI), where "mark" is 1 and "space" is 0.} \tn 
% Row Count 8 (+ 3)
% Row 3
\SetRowColor{white}
Guarantees a balanced signal because: & -1's are encoded in alternating +V, - V signal levels \tn 
% Row Count 11 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{If -V is a logical zero, and the two voltages +1V and -1V represents a logical zero, to send "1", the transmitter {\bf{alternates}} between +1V and -1V.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Bipolar Encoding Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590016734_Bipolar Encoding.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.43873 cm} x{2.53827 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Balanced Signal}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Base-band signal averages zero}} & As much + voltage as -, even after short period of time \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
{\bf{No DC electrical components}} & Advantangeous, as some channels (coaxial or lines with transformers) attenuate a DC component due to their physical properties \tn 
% Row Count 10 (+ 7)
% Row 2
\SetRowColor{LightBackground}
{\bf{DC component filtered out}} & Avoids energy waste \tn 
% Row Count 12 (+ 2)
% Row 3
\SetRowColor{white}
{\bf{Provides better clock recovery}} & Through transitions, due to mix of + and - volatages. \tn 
% Row Count 15 (+ 3)
% Row 4
\SetRowColor{LightBackground}
{\bf{Allows measuring the signal average}} & For error detection and receiver calibration. Impossible with an unbalanced signal \tn 
% Row Count 20 (+ 5)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Link Failure}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Instances for possible link failure:} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
Sequence used for scrambling could be the same as the signal & Transmitting all 0's, constituting a link failure \tn 
% Row Count 4 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{With unbalanced signals, the average may drift from the true decision level due to a density of 1s, for example, which would cause more symbols to be decoded with errors.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Capacity Coupling}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Method of {\bf{connecting the reciever to the channel.}}} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Passes only the AC portion of the signal.} \tn 
% Row Count 3 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.09034 cm} x{2.88666 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{4B/5B}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{A form of {\bf{line code}}} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Maps groups of 4 bits of data onto groups of 5 bits for transmission} \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Used to{\bf{ prevent more than 3 consecutive 0's}}} \tn 
% Row Count 4 (+ 1)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Every data (4B) has a fixed codeword(5) that it is translated to} \tn 
% Row Count 6 (+ 2)
% Row 4
\SetRowColor{LightBackground}
This scheme adds 25\% overhead & Better than the 100\% overhead of Manchester encoding \tn 
% Row Count 9 (+ 3)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Non-data codes can represent physical layer control signals} \tn 
% Row Count 11 (+ 2)
% Row 6
\SetRowColor{LightBackground}
e.g: "11111" - idle line & "11000" = start of a frame \tn 
% Row Count 13 (+ 2)
% Row 7
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Produces at least two transitions per 5 bit}}s of output code, regardless of input data.} \tn 
% Row Count 15 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{4B/5B Encoding Table}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590073625_4b5b.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{8B/10B}}  \tn
% Row 0
\SetRowColor{LightBackground}
Maps 8 bits input onto 10 bits output & 80\% efficient \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
Achieves DC signal balance, never far from balanced & At most 2 bit disparity \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{8 bits of data are transmitted as a 10-bit entity called a {\bf{symbol}}} \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
Low 5 bits are encoded into a 6 bit group & 5b/6b portion \tn 
% Row Count 10 (+ 3)
% Row 4
\SetRowColor{LightBackground}
Top 3 bits encoded into a 4-bit group & 3b/4b portion \tn 
% Row Count 12 (+ 2)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{These groups are concatenated together to form a 10-bit symbol that is transmitted.} \tn 
% Row Count 14 (+ 2)
% Row 6
\SetRowColor{LightBackground}
Standards also define up to 12 symbols that can be sent in place of a data symbol & These indicate start-of-frame, end-of-frame, link idle, etc. \tn 
% Row Count 19 (+ 5)
% Row 7
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Helps clock recovery, never more than 5 consecuive 1s or 0s} \tn 
% Row Count 21 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Passband Transmission}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Signals that are shifted to{\bf{ occupy a higher range of frequencies}}, (all wireless transmissions)} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Scheme that regulates the {\bf{amplitude}}, {\bf{phase}} or {\bf{frequency}} of a carrier signal to convey bits.} \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Occupies a band of frequencies around the frequency of the carrier signal.} \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Common for wireless and optical channels.} \tn 
% Row Count 8 (+ 1)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Regulatory constraints and intereference prevention dictates choice of frequencies.} \tn 
% Row Count 10 (+ 2)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Modulating the amplitude, frequency/phase of a carrier signal sends bits in a (non-zero) frequency range} \tn 
% Row Count 13 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Passband Transmission Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590079460_passband transmission.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{ASK, FSK, PSK}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.18988 cm} x{2.78712 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Regulating/modulating a carrier}}  \tn
% Row 0
\SetRowColor{LightBackground}
Amplitude Shift Keying ({\bf{ASK}}) & -Two different amplitudes  represent 0 and 1 \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
 & -More levels can represent more sumbols \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
Frequency Shift Keying ({\bf{FSK}}) & -Two or more tones used \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
Phase Shift Keying({\bf{PSK}}) & - Carrier wave systematicaly shifted 0 or 180 dgrees at each symbol period. \tn 
% Row Count 10 (+ 4)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Schemes can be combined and more levels used to transmit more bits per symbol. However, only one of frequency and phase can be modulated as they are related.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{ASK}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590247995_ASK.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Frequency Shift Keying ({\bf{FSK}})}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Two frequencies used} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{one symbol for 0, another for 1} \tn 
% Row Count 2 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{FSK Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590247915_FSK.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.68758 cm} x{2.28942 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Phase Shift Keying - {\bf{PSK}}}}  \tn
% Row 0
\SetRowColor{LightBackground}
Only Phase is modulated through time & to identify points on the plane \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Amplitude stays constant, {\bf{not}} modulated} \tn 
% Row Count 3 (+ 1)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Each point corresponds to one of four symbols.} \tn 
% Row Count 4 (+ 1)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{2 bits per symbol transmitted} \tn 
% Row Count 5 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Example: \newline  \newline To indentify 4 vertices("quadrature") of a square centered plane. Each point corresponds to 4 symbols. \newline As there are 4 symbols, 2 bits per symbol are transmitted.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{PSK}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590247958_PSK.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Constellation Diagrams}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Shorthand to capture the amplitude and phase modulations symbols} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{The points give the {\bf{legal amplitude and phase combinations}} of each symbol.} \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{The {\bf{phase}} of a dot is indicated by the {\emph{angle a line from it to the origin makes with the positive x-axis}}} \tn 
% Row Count 7 (+ 3)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{The {\bf{amplitude}} of a dot is the {\emph{distance from the origin}}} \tn 
% Row Count 9 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Constellation Diagram Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590080434_constellation diagram.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.78712 cm} x{2.18988 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{QAM-16}}  \tn
% Row 0
\SetRowColor{LightBackground}
QAM & Quadrature Amplitude Modulation \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
16 combinations of amplitudes and phase used & Can transmit 4 bits per symbol \tn 
% Row Count 4 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{A denser modulation scheme with 64 different combinations is called QAM-64. There are even higher-order QAMs used.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.53827 cm} x{2.43873 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Gray-Coding}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Assigns(maps) bits to symbols so that adjacent symbols differ in only 1 bit position} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
If a receiver decodes the symbol in error & It will make only a single bit in error \tn 
% Row Count 5 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Gray-coding Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590081289_Gray-coding.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{Gray-coded QAM-16 constellation}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Multiplexing}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Channels shared by multiple signals} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{More convenient than using a single wire to carry several signals than to install a wire for every signal.} \tn 
% Row Count 4 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Frequency Division Multiplexing({\bf{FDM}})}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Divides the spectrum into frequency bands. e.g. AM radio} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Shares the channel by placing users on different frequencies} \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Frequencies are allocated different logical channels, with interchannel separation great enough to prevent interference} \tn 
% Row Count 7 (+ 3)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Subcarriers are coordinated to be tightly packed} \tn 
% Row Count 8 (+ 1)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Filters}} limit the useable bandwidth to 3100hz p/voice-grade channel.} \tn 
% Row Count 10 (+ 2)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Many channels multiplexed together, 4000hz allocated per channel} \tn 
% Row Count 12 (+ 2)
% Row 6
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Different frequencies encode different values, while phase and amplitude remain constant.} \tn 
% Row Count 14 (+ 2)
% Row 7
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Higher frequency is associated to 1 bit, and a lower to 0} \tn 
% Row Count 16 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Separations(the excess) are called {\bf{guard bands}}. Even though there is a large gap, some adjacent channels do overlap because filters do not have ideal 'sharp edges', therefore a strong spike at the edge of one channel will be felt in jacanet as {\emph{nonthermal noise}}}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Frequency Division Multiplexing Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590097162_FDM.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{(a) The original bandwidths \newline (b) The bandwidths raised in frequency \newline (c) The Multiplexed channel}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Orthogonal FDM ({\bf{OFDM}})}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{OFDM (Orthogonal FDM) is an efficient FDM technique used for 802.11, 4G cellular and other communications that does not use guard bands.} \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{The channel is divided into many subcarriers that independently send data.} \tn 
% Row Count 5 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Subcarriers are tightly packed in the frequency domain.} \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Frequency response of each subcarrieris zero at the center of adjacent subcarriers, therefore subcarriersbe sampled at their center frequencies without interference from neighbours} \tn 
% Row Count 11 (+ 4)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Guard time}} required to repeat ports of symbol signals so that they have the desired frequency} \tn 
% Row Count 13 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.9862 cm} x{1.9908 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Time Division Multiplexing}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Shares a channel over time} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
Users take turns on a fixed schedule & {\bf{Not packet switching}} \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Each gets the entire badwidth for a little burst of time} \tn 
% Row Count 5 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Bits from each input stream are taken in a fixed {\bf{time slot}} and output to the aggregate stream.} \tn 
% Row Count 7 (+ 2)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{This stream runs the {\emph{sum rate}} of individual streams.} \tn 
% Row Count 9 (+ 2)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Streams must be {\emph{synchronized}} in time.} \tn 
% Row Count 10 (+ 1)
% Row 6
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Widely used in telephone/cellular systems} \tn 
% Row Count 11 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Small intervals of {\bf{guard time}}  analoguous to a requency guard band may be added to accomodate small timing variations}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Time Division Multiplexing Image}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{p{5.377cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/bayan-a_1590097318_TDM.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{Three streams being multiplexed with TDM.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.09034 cm} x{2.88666 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Code Divison Multiple Access}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Shares the channel by giving users a code} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
Codes are orthogonal & Can be sent at the same time \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Widely used as part of 3G networks} \tn 
% Row Count 4 (+ 1)
% Row 3
\SetRowColor{white}
{\bf{Scalar Product}} (example): & A ● B = (a₁, a₂, a₃) ● (b₁, b₂, b₃) = a₁b₁ + a₂b₂ + a₃b₃ \tn 
% Row Count 8 (+ 4)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Walsh Codes}} (example): \newline {\bf{A}} = (a₁ , a₂, a₃)    {\bf{A̅}}  = (-a₁ , -a₂, -a₃) \newline {\bf{B}} =(b₁ , b₂, b₃)      {\bf{B̅}} = (-b₁ , -b₂, -b₃) \newline  \newline {\bf{Properties of CDMA codes:}} \newline For all {\bf{A}}, {\bf{B}} with {\bf{A}} ≠ {\bf{B}} \newline {\bf{A}} ●  {\bf{A}} = +1 \newline {\bf{A}} ●  {\bf{A̅}} = -1 \newline {\bf{A}} ●  {\bf{B}} = {\bf{A}}   {\bf{B}} = 0   \newline  \newline {\bf{Transmission:}} \newline A, B and C transmit 1, 1 and 0 respectively \newline A, B and C send codes {\bf{A}}, {\bf{B}} and {\bf{C̅}} respectively \newline The receiver sees {\bf{A}} + {\bf{B}} + {\bf{C̅}}}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Code Division Multiple Access({\bf{CDMA}})}}  \tn
% Row 0
\SetRowColor{LightBackground}
A form of {\bf{spread spectrum}} communication & Narrowband signal spread out over a wider frequency band \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Tolerant of interference.} \tn 
% Row Count 4 (+ 1)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Allows multiple signals from different users to share the same frequency band.} \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{CDMA shares the channel by giving users a code} \tn 
% Row Count 7 (+ 1)
% Row 4
\SetRowColor{LightBackground}
Codes are orthogonal; & Can be sent at the same time \tn 
% Row Count 9 (+ 2)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Widely used as part of 3G networks} \tn 
% Row Count 10 (+ 1)
% Row 6
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Each station can transmit over the entire frequency spectrum all the time} \tn 
% Row Count 12 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Can also be called "Code Division Multiplexing", but because it is used mostly to allow the same frequency band to be shared by different users by multiple signals, it was commonly called Code Division Multiple {\emph{Access}}}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}