Added data rate to parameters list of TxProfile constructor in WAVE module

According to IEEE 1609.4 paragraph 7.3.4.2 MLMEX-REGISTERTXPROFILE.request tx profile registration primitive shall provide a data rate parameter.

In current TxProfile class implementation the data rate is not provided as a parameter in constructor so it doesn't allow user to specify transmission data rate according to IEEE 1609.4 standard. 

Also it forces to use 6Mbps as lowest data rate so if a user uses 4.5 or 3Mbps data rate using ConstantRateWifiManager and measures throughput between 2 WAVE nodes then the throughput will be around 4.5Mbps for all 3 data rates (3, 4.5, 6Mbps).

The patch simply adds the data rate parameter to parameters list of TxProfile constructor.

The patch is tested on ns-3.26 +changeset 12778

[Pavel Vasilyev, 2017-03-20 13:50:02]

Hi guys,

I've used ns3 WAVE module to test throughput between 2 WAVE nodes and I found
out that for 3 lowest data rates: 3Mbps, 4.5Mbps and 6Mbps the throughput is
always the same. 

I dug into the issue and found out that TxProfile shall provide data rate
parameter according to IEEE 1609.4 standard to allow user to specify
transmission data rate. For now the implementation forces to use 6Mbps data rate
if user chooses 3Mbps or 4.5Mbps in case of adaptable mode, and forces to use
6Mbps in non-adaptable mode.

Here is sample code you can try to check the path:
http://pastebin.com/H80xgduh

In the code I choose 3Mbps data rate, but throughput is around 4.5Mbps. With the
patch you can uncomment the line 141 and comment line 138 to see that throughput
is around 2.5Mbps.

Thanks!

Best regards,
Pavel Vasilyev.