extend PhyTxRx to consider antenna gain and max power

[lthiery]

Resolves #150

[lulf]

Why couldn't this be just added to PhyRxTx with default impls to avoid the extra generic arg?

[lthiery]

Why couldn't this be just added to PhyRxTx with default impls to avoid the extra generic arg?

Thanks for the feedback! I think you're right and I tried it out combined with @plaes 's const generic suggestion.

[plaes]

What I do not like with current design is that it's somewhat error-prone as it has to be "manually" adjusted every time mac.{send,join_otaa} creates TxConfig object.

Ideally it should be already adjusted whenever this object is craeted which happens in only two places:

• join_otaa
• send
  Or alternatively it should happen when this instance is used (one possibility could be adding extra optional argument for radio.tx(...) in lora-phy)?

[lthiery]

What I do not like with current design is that it's somewhat error-prone as it has to be "manually" adjusted every time mac.{send,join_otaa} creates TxConfig object.

Thanks for the idea @plaes. Your point is why my first iteration passed a const generic to the Mac struct initially, but @lulf 's feedback made me think that the mental load of yet another trait seemed unnecessary and I liked the UX of the trait associated const.

I was going to do Mac<R::MAX_RADIO_POWER,R::ANTENNA_GAIN> but that depends on generic_const_exprs which can only be enabled in nightly. Even with that feature enabled, I couldn't quite get it to work and the compiler was telling me that the expressions were not properly constrained...

Therefore, the current solution is to use the trait constants to instantiate the Mac with the appropriate limits. This at least passes the responsibility the adjustment to join_otaa and send making it harder to make a mistake in the future.