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General VHT rate-ctrl question

DISCUSSION Ben Greear 4 participants 5 messages Apr 12, 2016 – Apr 13, 2016

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Ben Greear

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If a station and it's peer can both do VHT, is there ever a good reason to even try HT rates?

Thanks,
Ben

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Ben Greear <[email protected]>
Candela Technologies Inc  http://www.candelatech.com
#1 lore raw
Quoted 3 lines · Ben Greear

If a station and it's peer can both do VHT, is there ever a good reason to even try HT rates?

Not really; perhaps if you could do HT greenfield preamble (which VHT doesn't have) you could get something out of it, beyond that I don't see a reason to try.

Unless, for some strange reason, it supports only single stream VHT and dual-stream HT or something really weird?

johannes

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#2 lore raw
Quoted 11 lines · Johannes Berg
Quoted 3 lines · Ben Greear

If a station and it's peer can both do VHT, is there ever a good reason to even try HT rates?

Not really; perhaps if you could do HT greenfield preamble (which VHT doesn't have) you could get something out of it, beyond that I don't see a reason to try.

Unless, for some strange reason, it supports only single stream VHT and dual-stream HT or something really weird?

I was wondering if there was ever a reason that, say 450Mbps HT would work better than MCS-1 for VHT. Or, maybe a mid-rate HT MCS would have more range than VHT, or something like that.

After fighting with the firmware's rate-ctrl all day, I am even more interested in trying to make it use mistrel_ht.

Thanks,
Ben

Signature · 2 lines
Ben Greear <[email protected]>
Candela Technologies Inc  http://www.candelatech.com
#3 lore raw
Quoted 18 lines · Ben Greear
Quoted 7 lines · Johannes Berg
Quoted 4 lines · Ben Greear

If a station and it's peer can both do VHT, is there ever a good reason to even try HT rates?

Quoted 6 lines

Not really; perhaps if you could do HT greenfield preamble (which VHT doesn't have) you could get something out of it, beyond that I don't see a reason to try.

Unless, for some strange reason, it supports only single stream VHT and dual-stream HT or something really weird?

Quoted 7 lines

I was wondering if there was ever a reason that, say 450Mbps HT would work better than MCS-1 for VHT. Or, maybe a mid-rate HT MCS would have more range than VHT, or something like that.

After fighting with the firmware's rate-ctrl all day, I am even more interested
in trying to make it use mistrel_ht.

I just put up Andrew's old paper on minstrel, if that helps any.

http://blog.cerowrt.org/post/minstrel/

Quoted 11 lines

Thanks,
Ben

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Ben Greear <[email protected]>
Candela Technologies Inc http://www.candelatech.com
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#4 lore raw
Quoted 16 lines · Dave Taht
Quoted 14 lines · Ben Greear
Quoted 11 lines · Johannes Berg
Quoted 4 lines · Ben Greear

If a station and it's peer can both do VHT, is there ever a good reason to even try HT rates?

Not really; perhaps if you could do HT greenfield preamble (which VHT doesn't have) you could get something out of it, beyond that I don't see a reason to try.

Quoted 7 lines
Quoted 7 lines
Quoted 2 lines

Unless, for some strange reason, it supports only single stream VHT and dual-stream HT or something really weird?

I was wondering if there was ever a reason that, say 450Mbps HT would work better than MCS-1 for VHT. Or, maybe a mid-rate HT MCS would have more range than VHT, or something like that.

I dont think so. basically if you remove 256 QAM out of picture, it just boils down to choosing a modulation scheme which would be same for VHT and HT. (assuming same BW)

Only advantage is as Johannes pointed, VHT doesn't have greenfield, so using HT greenfield preamble might be marginally good. Similarly we can use RIFS for HT(not recommended), But again who uses RIFS/greenfield?