add example that shows PAPR reduction by using nrTransformPrecode()

Author: catkira

examples/papr_comparison.ipynb

@@ -0,0 +1,88 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import numpy as np\n",
+    "import matplotlib.pyplot as plt\n",
+    "from py3gpp import *"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 58,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "NFFT = 10\n",
+    "ZERO_CARRIER = 400"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 72,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "PAPR = 9.322 dB\n"
+     ]
+    }
+   ],
+   "source": [
+    "cw = np.random.randint(0, 2, (2**NFFT - ZERO_CARRIER)*2)\n",
+    "grid = np.zeros((2**NFFT, 1), np.complex128)\n",
+    "grid[ZERO_CARRIER//2:-ZERO_CARRIER//2, 0] = nrSymbolModulate(cw, 'QPSK')\n",
+    "waveform, _ = nrOFDMModulate(grid = grid)\n",
+    "power = np.real(np.multiply(waveform, waveform.conj()))\n",
+    "print(f\"PAPR = {10*np.log10(np.max(power)/np.mean(power)):.04} dB\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "PAPR = 6.304 dB\n"
+     ]
+    }
+   ],
+   "source": [
+    "grid[ZERO_CARRIER//2:-ZERO_CARRIER//2, 0] = nrTransformPrecode(nrSymbolModulate(cw, 'QPSK'), (2**NFFT - ZERO_CARRIER)//12)\n",
+    "waveform, _ = nrOFDMModulate(grid = grid)\n",
+    "power = np.real(np.multiply(waveform, waveform.conj()))\n",
+    "print(f\"PAPR with DFT-s precoding = {10*np.log10(np.max(power)/np.mean(power)):.04} dB\")"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.12"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}