In particular, this commit contains:
* a new abstract class ChannelConditionModel, which provides the base for the
implementation of specific channel condition models. The main method is
GetChannelCondition (mm a, mm b), which determines the channel condition
based on the tx and rx mobility models and returns it as a pointer to an
object of type ChannelCondition
* the implementation of the subclasses ThreeGppRMaChannelConditionModel,
ThreeGppUMaChannelConditionModel, ThreeGppUMiStreetCanyonChannelConditionModel,
ThreeGppIndoorMixedOfficeChannelConditionModel,
ThreeGppIndoorOpenOfficeChannelConditionModel, which inherits from
ChannelConditionModel and statistically determines the LOS/NLOS state based on
the specification in 3GPP TR 38.901
* the implementation of the subclass BuildingsChannelConditionModel, which
inherits from ChannelConditionModel and determines the LOS/NLOS state based
on the buildings deployed in the scenario. It has been adapted from the
mmwave module.
* new classes which extends the PropagationLossModel interface and implements
the pathloss models defined in 3GPP TR 38.901
(ThreeGppRmaPropagationLossModel, ThreeGppUmaPropagationLossModel,
ThreeGppUmiStreeCanyonPropagationLossModel,
ThreeGppIndoorOfficePropagationLossModel). The main method is DoCalcRxPower
(txPow, mm a, mm b), which applies the pathloss model taking into account the
LOS/NLOS channel state and then returns the received power. To retrieve the
channel state, they interface with the class ChannelConditionModel through
the method GetChannelCondition (mm a, mm b)
* documentation and test cases for all the new classes
SocketAddressTag was a long-standing API glitch. It was used to replicate the RecvFrom effect (i.e., to know the source address of packet) without calling RecvFrom.
This option is more harmful than useful, because in case of tunnels the new tag needs to replace the old one. Moreover, there is no real need to create a new API when there is a perfectly working one (i.e., RecvFrom).
