Commit 46ae3f9cf1b442cd209f9c4021cf6238d8f7e2b7

Authored by Arthur HUGEAT
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Final draft.

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ifcs2018_journal.tex
... ... @@ -111,7 +111,7 @@
111 111 will result in some precision loss.
112 112  
113 113 \begin{figure}[h!tb]
114   -\includegraphics[width=\linewidth]{images/demo_filtre}
  114 +\includegraphics[width=\linewidth]{images/zero_values}
115 115 \caption{Impact of the quantization resolution of the coefficients: the quantization is
116 116 set to 6~bits -- with the horizontal black lines indicating $\pm$1 least significant bit -- setting
117 117 the 30~first and 30~last coefficients out of the initial 128~band-pass
118 118  
... ... @@ -251,14 +251,14 @@
251 251  
252 252 \begin{figure}
253 253 \centering
254   -\includegraphics[width=\linewidth]{images/mean_criterion}
  254 +\includegraphics[width=\linewidth]{images/colored_mean_criterion}
255 255 \caption{Mean criterion comparison between monolithic filter and cascade filters}
256 256 \label{fig:mean_criterion}
257 257 \end{figure}
258 258  
259 259 \begin{figure}
260 260 \centering
261   -\includegraphics[width=\linewidth]{images/custom_criterion}
  261 +\includegraphics[width=\linewidth]{images/colored_custom_criterion}
262 262 \caption{Custom criterion comparison between monolithic filter and cascade filters}
263 263 \label{fig:custom_criterion}
264 264 \end{figure}
265 265  
... ... @@ -278,11 +278,16 @@
278 278  
279 279 \begin{figure}
280 280 \centering
281   -\includegraphics[width=\linewidth]{images/sum_rejection}
  281 +\includegraphics[width=\linewidth]{images/cascaded_criterion}
282 282 \caption{Rejection of two cascaded filters}
283 283 \label{fig:sum_rejection}
284 284 \end{figure}
285 285  
  286 +The first problem we address is to maximize the rejection under bounded silicon area
  287 +and feasibility constraints. Variable $a_i$ is the area taken by filter~$i$
  288 +(in arbitrary unit). Variable $r_i$ is the rejection of filter~$i$ (in dB).
  289 +Constant $\mathcal{A}$ is the total available area. We model our problem as follows:
  290 +
286 291 Finally we can describe our abstract model with following expressions :
287 292 \begin{align}
288 293 \text{Maximize } & \sum_{i=1}^n r_i \notag \\
... ... @@ -295,10 +300,6 @@
295 300 \pi_1^- &= \Pi^I \label{eq:init}
296 301 \end{align}
297 302  
298   -{\color{red} Je sais que l'idée est de ne pas parler du programme linéaire mais
299   -ça me semble quand même indispensable. Au pire, j'essaierai de revoir ça si on
300   -est vraiment en manque de place.}
301   -
302 303 Equation~\ref{eq:area} states that the total area taken by the filters must be
303 304 less than the available area. Equation~\ref{eq:areadef} gives the definition of
304 305 the area for a filter. More precisely, it is the area of the FIR as the Shifter
... ... @@ -324,9 +325,9 @@
324 325  
325 326 This model is non-linear and even non-quadratic, as $F$ does not have a known
326 327 linear or quadratic expression. We introduce $p$ FIR configurations
327   - $(C_{ij}, \pi_{ij}^C), 1 \leq j \leq p$ that are constants. We define binary
328   - variable $\delta_{ij}$ that has value 1 if stage~$i$ is in configuration~$j$
329   - and 0 otherwise. The new equations are as follows:
  328 +$(C_{ij}, \pi_{ij}^C), 1 \leq j \leq p$ that are constants. We define binary
  329 +variable $\delta_{ij}$ that has value 1 if stage~$i$ is in configuration~$j$
  330 +and 0 otherwise. The new equations are as follows:
330 331  
331 332 \begin{align}
332 333 a_i & = \sum_{j=1}^p \delta_{ij} \times C_{ij} \times (\pi_{ij}^C + \pi_i^-), & \forall i \in [1, n] \label{eq:areadef2} \\
... ... @@ -339,7 +340,12 @@
339 340 respectively equations \ref{eq:areadef}, \ref{eq:rejectiondef} and \ref{eq:bits}.
340 341 Equation~\ref{eq:config} states that for each stage, a single configuration is chosen at most.
341 342  
342   -The next section shows the results for this quadratic program but the section~\ref{sec:fixed_rej}
  343 +This modified model is quadratic, and it can be linearised if necessary. The Gurobi
  344 +(\url{www.gurobi.com}) optimization software is used to solve this quadratic
  345 +model, and since Gurobi is able to linearize, the model is left as is. This model
  346 +has $O(np)$ variables and $O(n)$ constraints.
  347 +
  348 +The section~\ref{sec:fixed_area} shows the results for the first version of quadratic program but the section~\ref{sec:fixed_rej}
343 349 presents the results for the complementary problem. In this case we want
344 350 minimize the occupied area for a targeted rejection level. Hence we have replace
345 351 the objective function with:
images/cascaded_criterion.pdf
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images/colored_custom_criterion.pdf
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images/colored_mean_criterion.pdf
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images/criterion_cascaded.pdf
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images/zero_values.pdf
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