Question on tx-power and number of chains.

Suppose a NIC wants to decrease TX power for certain rates based on the number of chains (ie, subtract amount A from requested rate for 2 chains, and B for 3 chains).

I assume the NIC wants to do this is because if the pkt is transmitted out each antenna, then there is ~3x the power put onto the air.

Now, the question is, should this power-decrease be per rate, and perhaps different for each rate, or can all rates use all tx-chains (and so tx-power should be decreased the same maximum amount based on the hardware's number of chains for each rate).

I am thinking that CCK rates can only ever be transmitted by a single chain, so in that case those rates would not need their power decreased from the requested?

And if that is so, what about the /a/g/ rates, and lower-speed HT/VHT rates as well?

Is there a table somewhere that explains how many chains are used by each rate?

Thanks,
Ben

Ben Greear <[email protected]>
Candela Technologies Inc  http://www.candelatech.com

mcsindex.com?

Nice. Adding that to my bookmarks. What happened to that quirky MCS32.

Regards,
Arend

It's the unloved stepchild ;-)

They also removed all the other higher HT ones (>32) when adding VHT. You can still find an old version on archive.org IIRC.

johannes

What about OFDM and CCK. Are those always 1 chain?

Thanks,
Ben

Ben Greear <[email protected]>
Candela Technologies Inc  http://www.candelatech.com

They're 1 stream at least, so only one chain is needed. I'm not entirely sure you couldn't transmit them on multiple chains but I don't think it'd make that much sense?

johannes