doc: Fix greek letters within model documentation

In Europe, people are advanced and use an UTF-* compatible charset, that
permits them to use many more letters than countries that
rely on ASCII. Unfortunately, latex still doesn't recognize all
these new character, so we have to use special escape sequences.

Close #188

src/internet/doc/tcp.rst

@@ -810,11 +810,11 @@ latency, and high throughput with shallow-buffered switches.
 
 * Receiver functionality: If CE is set in IP header of incoming packet, send congestion notification to the sender by setting ECE in TCP header. This processing is different from standard ECN processing which sets ECE bit for every ACK until it observes CWR
 
-* Sender functionality: The sender makes use of the modified receiver ECE semantics to maintain an average of fraction of packets marked (α) by using the exponential weighted moving average as shown below:
+* Sender functionality: The sender makes use of the modified receiver ECE semantics to maintain an average of fraction of packets marked (:math:`\alpha`) by using the exponential weighted moving average as shown below:
 
 .. math::
 
-               α = (1 - g) x α + g x F
+               \alpha = (1 - g) x \alpha + g x F
 
 where
 
@@ -827,7 +827,7 @@ window as follows, once for every window of data:
 
 .. math::
 
-               cwnd = cwnd * (1 - α / 2)
+               cwnd = cwnd * (1 - \alpha / 2)
 
 Following the recommendation of RFC 8257, the default values of the parameters are:
 
@@ -835,7 +835,7 @@ Following the recommendation of RFC 8257, the default values of the parameters a
 
   g = 0.0625 (i.e., 1/16)
 
-  initial alpha (α) = 1
+  initial alpha (\alpha) = 1
 
 
 

src/spectrum/doc/spectrum.rst

@@ -592,10 +592,10 @@ The framework described by TR 38.901 [TR38901]_ is a 3D statistical Spatial
 Channel Model supporting different propagation environments (e.g., urban,
 rural, indoor), multi-antenna operations and the modeling of wireless channels
 between 0.5 and 100 GHz.
-The overall channel is represented by the matrix H(t,τ), in which each
-entry H :sub:`u,s` (t,τ) corresponds to the impulse response of the channel between the
+The overall channel is represented by the matrix :math:`H(t,\tau)`, in which each
+entry H :sub:`u,s` :math:`(t,\tau)` corresponds to the impulse response of the channel between the
 s-th element of the transmitting antenna and the u-th element of the receiving
-antenna. H :sub:`u,s` (t,τ) is generated by the superposition of N different multi-path
+antenna. H :sub:`u,s` :math:`(t,\tau)` is generated by the superposition of N different multi-path
 components, called clusters, each of which composed of M different rays.
 The channel matrix generation procedure accounts for large and small scale
 propagation phenomena. The classes ThreeGppSpectrumPropagationLossModel and

src/uan/doc/uan.rst

@@ -259,7 +259,7 @@ AUV energy sources
 Acoustic modem energy model
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Basing on the Device Energy Model interface, has been implemented a generic energy model for acoustic modem. The model allows to trace four modem's power-states: Sleep, Idle, Receiving, Transmitting. The default parameters for the energy model are set to fit those of the WHOI μmodem. The class follows pretty closely the RadioEnergyModel class as the transducer behaviour is pretty close to that of a Wi-Fi radio.
+Basing on the Device Energy Model interface, has been implemented a generic energy model for acoustic modem. The model allows to trace four modem's power-states: Sleep, Idle, Receiving, Transmitting. The default parameters for the energy model are set to fit those of the WHOI :math:`\mu`-modem. The class follows pretty closely the RadioEnergyModel class as the transducer behaviour is pretty close to that of a Wi-Fi radio.
 
 The default power consumption values implemented into the model are as follows [6]_: