initial checkin of gnumeric path loss functions

This code extends gnumeric with some functions to compute the RF
propagation path loss by some common models.

3 files changed, 472 insertions, 0 deletions

diff --git a/pathloss/COPYING b/pathloss/COPYING
new file mode 100644
index 0000000..d159169
--- /dev/null
+++ b/pathloss/COPYING
@@ -0,0 +1,339 @@
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diff --git a/pathloss/pathloss-func.py b/pathloss/pathloss-func.py
new file mode 100644
index 0000000..a9e9a65
--- /dev/null
+++ b/pathloss/pathloss-func.py
@@ -0,0 +1,112 @@
+# pathloss-func.py
+
+# (C) 2016 by Harald Welte <laforge@gnumonks.org>
+# All Rights Reserved
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from Gnumeric import GnumericError, GnumericErrorVALUE
+import Gnumeric
+import string
+import math
+
+def lambda_by_mhz(freq_mhz):
+    return 300/freq_mhz
+
+def func_fsl(freq_mhz, dist_m):
+    '@FUNCTION=PATHLOSS_FREESPACE\n'\
+    '@SYNTAX=pathloss_freespace(freq_mhz, dist_m)\n'\
+    '@DESCRIPTION=Compute Free Space Path Loss (in dB)\n'\
+    '@SEEALSO=pathloss_egli,pathloss_hata\n'
+
+    wavelen = lambda_by_mhz(freq_mhz)
+
+    return -20 * math.log10(wavelen / (4*3.1416*dist_m))
+
+def hata_ch(envi, freq_mhz, rx_ant_m):
+    logfreq = math.log10(freq_mhz)
+    ch = 0
+    if envi == 'city_small' or envi == 'city_medium':
+        ch = 0.8 + (1.1 * logfreq - 0.7)*rx_ant_m - (1.56 * logfreq)
+    elif envi == 'city_large':
+        if freq_mhz < 200:
+            ch = 8.29 * math.pow(math.log10(1.54*rx_ant_m), 2) - 1.1
+        elif freq_mhz > 200:
+            ch = 3.2 * math.pow(math.log10(11.75*rx_ant_m), 2) - 4.97
+    return ch
+
+def hata_cm(envi, freq_mhz):
+    logfreq = math.log10(freq_mhz)
+    att = 0
+    if freq_mhz <= 1500:
+        if envi == 'open_area' or envi == 'rural':
+            # https://en.wikipedia.org/wiki/Hata_model_for_open_areas
+            att = -4.78 * math.pow(logfreq, 2) + 18.33 * logfreq - 40.94
+        elif envi == 'suburban':
+            # https://en.wikipedia.org/wiki/Hata_model_for_suburban_areas
+            att = -2 * math.pow(logfreq/28, 2) - 5.4
+    else:
+        if envi == 'city_large':
+            att = 3
+        else:
+            att = 0
+    return att
+
+def func_hata(envi, freq_mhz, dist_m, bts_ant_m, ms_ant_m):
+    '@FUNCTION=PATHLOSS_HATA\n'\
+    '@SYNTAX=pathloss_hata(environment, freq_mhz, dist_m, bts_ant_m, ms_ant_m)\n'\
+    '@DESCRIPTION=Compute Path Loss (in dB) as per Hata Model\n'\
+    '@SEEALSO=pathloss_freespace,pathloss_hata\n'
+
+    # FIXME: valid for 150MHz - 2GHz, MS 1-10m, BS 30-200m, dist # 1-10km
+    environs = ('open_area', 'rural', 'suburban', 'city_small',
+                'city_medium', 'city_large')
+    if not envi in environs:
+        raise GnumericError,GnumericErrorVALUE
+
+    # http://morse.colorado.edu/~tlen5510/text/classwebch3.html
+    if freq_mhz <= 1500:
+        c0 = 69.55
+        cf = 26.16
+    else:
+        c0 = 46.3
+        cf = 33.9
+
+    # https://en.wikipedia.org/wiki/Hata_model_for_urban_areas
+    hata = c0 + cf * math.log10(freq_mhz)
+    hata -= 13.82 * math.log10(bts_ant_m)
+    hata -= hata_ch(envi, freq_mhz, ms_ant_m)
+    hata += (44.9 - 6.55 * math.log10(bts_ant_m)) * math.log10(dist_m/1000)
+    # subtract correction for open_area / suburban
+    hata += hata_cm(envi, freq_mhz)
+
+    return hata
+
+def func_egli(freq_mhz, dist_m, tx_ant_m, rx_ant_m):
+    '@FUNCTION=PATHLOSS_EGLI\n'\
+    '@SYNTAX=pathloss_egli(freq_mhz, dist_m, tx_ant_m, rx_ant_m)\n'\
+    '@DESCRIPTION=Compute Path Loss (in dB) as per Egli Model\n'\
+    '@SEEALSO=foo\n'
+
+    # https://en.wikipedia.org/wiki/Egli_model
+    att = -20 * math.log10(rx_ant_m*tx_ant_m / (dist_m*dist_m))
+    att += 20 * math.log10(freq_mhz/40)
+
+    return att
+
+pathlossfunc_functions = {
+    'pathloss_freespace': ('ff', 'freq_mhz, dist_m', func_fsl),
+    'pathloss_egli': ('ffff', 'freq_mhz, dist_m, tx_ant_m, rx_ant_m', func_egli),
+    'pathloss_hata': ('sffff', 'environ, freq_mhz, dist_m, bts_ant_m, ms_ant_m', func_hata),
+}
diff --git a/pathloss/plugin.xml b/pathloss/plugin.xml
new file mode 100644
index 0000000..8ece45a
--- /dev/null
+++ b/pathloss/plugin.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0"?>
+<plugin id="Gnumeric_pathlossFuncPlugin">
+	<information>
+		<name>RF Path Loss Functions</name>
+		<description></description>
+	</information>
+	<loader type ="Gnumeric_PythonLoader:python">
+		<attribute name="module_name" value="pathloss-func"/>
+	</loader>
+	<services>
+		<service type="function_group" id="pathlossfunc">
+			<category>Local Python</category>
+			<functions>
+				<function name='pathloss_freespace'/>
+				<function name='pathloss_egli'/>
+				<function name='pathloss_hata'/>
+				<function name='pathloss_cost_hata'/>
+			</functions>
+		</service>
+	</services>
+</plugin>