[Ns-developers] Adding Wifi Phy models

[Pei, Guangyu]

Mathieu,

I have some questions about adding additional PHY models (such as
802.11b/g) in ns-3.

Currently, there is a YansWifiPhy, which aligns with 802.11a PHY. It
works together with interference-helper, yans-error-rate-model and
yans-wifi-channel.

It seems to me that Yans model is generic and can be used as the bases
for the other PHY models.

How about the following approach for adding additional PHY model?

(1) generalize interference-helper based on PHY standard type: 

Instead of assuming 802.11a parameter, add a member variable "enum
WifiPhyStandard m_80211_standard". In
InterferenceHelper::CalculateTxDuration(), the TxDuration is calculated
based on m_80211_standard. For each standard type x, there should be a
"Configure80211xParameters" function.

(2) add new PHY modes in wifi-phy (e.g., Get1mbb for 802.11b 1Mbps etc)

(3) Add Chunk success rate functions in yans-error-rate-model based on
new modes added in WifiPhy.

(4) In YansWifiPhy, the only thing need is to add Configure80211x() to
support YansWifiPhy::SetStandard for new 802.11x mode added.

Is this approach acceptable? The pros of this approach is that new modes
can leverage Yans model heavily. As you can see only minor changes
needed for YansWifiPhy class. The cons of this approach may be that it
is not modular since it directly add new PHY models on top of Yans
model. 

Another approach is that each additional PHY mode is standalone module,
which has its own error-rate-model, interference-helper etc. But I see a
lot of overlapping codes for this approach. What are your thoughts for
this type of approach?

Since Yans model seems to align with 802.11a well, what is the reason
not to call it 802.11a and set default parameters such as receiver
sensitivity more closely to the standard? What is your vision and plan
for adding other 802.11 PHY models within your current framework.

Thanks,

Gary