Yes, radios will negotiate different rx/tx rates to each other, so up to 2
distinct rates for a single link. On the open source mac80211
linux-wireless driver you can see this explicitly. The rx/tx on one radio
is the tx/rx on the other.
root@ap1:~# iw wlan0 station dump
Station 52:e6:fc:XX:XX:XX (on wlan0)
inactive time: 70 ms
rx bytes: 769202553
rx packets: 4644034
tx bytes: 326581907
tx packets: 465139
tx retries: 76461
tx failed: 4
signal: -56 [-57, -62] dBm
signal avg: -55 [-57, -62] dBm
tx bitrate: 117.0 MBit/s MCS 14
rx bitrate: 86.7 MBit/s MCS 12 short GI
authorized: yes
authenticated: yes
preamble: long
WMM/WME: yes
MFP: no
TDLS peer: no
root@ap2:~# iw wlan0 station dump
Station 62:66:b3:XX:XX:XX (on wlan0)
inactive time: 10 ms
rx bytes: 569548806
rx packets: 3191667
tx bytes: 412571117
tx packets: 490879
tx retries: 104831
tx failed: 1
signal: -57 [-67, -57] dBm
signal avg: -55 [-62, -56] dBm
tx bitrate: 86.7 MBit/s MCS 12 short GI
rx bitrate: 117.0 MBit/s MCS 14
authorized: yes
authenticated: yes
preamble: long
WMM/WME: yes
MFP: no
TDLS peer: no
On Thu, Nov 13, 2014 at 3:27 PM, Colton Conor <[email protected]>
wrote:
> In my situation, we are assuming we are dealing with a location with one
> and only one AP (typical home) and most devices are tablets and smartphones
> who's antenna's and power output can't be modified. Can be either a 1 or 2
> story home.
>
> So, how much truth is in this article:
> http://tomatousb.org/tut:increasing-wrt54g-transmit-power
>
> The author is claiming that wifi negotiates speed (correct) but in both
> directions in the uplink and downlink side. He is basically claiming if you
> increase the power output at the AP, then the downstream (from AP to
> client) link rate will increase, while the uplink (Client to AP) will stay
> the same. This make sense, but does wifi really established a different PHY
> rate for up and down stream. Is this correct?
>
>
>
> On Thu, Nov 13, 2014 at 3:09 PM, Jack Unger <[email protected]> wrote:
>
>> Going from 20 dB to 26 dB will allow the AP to be heard (with the same
>> reliability) at double the distance away.
>>
>> Yes. If the client power (actually the client EIRP which includes the
>> antenna gain) stays the same then the "uplink" distance from client to AP
>> will still be the same.
>>
>> Yes, increasing the number of APs is one possible solution. Another is to
>> use a higher-gain (more directional) antenna on the AP recognizing that
>> when you increase the AP antenna gain in one direction, you are reducing
>> the gain (and the coverage) in all other directions.
>>
>> jack
>>
>> On 11/13/2014 11:10 AM, Colton Conor wrote:
>>
>> So going from a regular powered 100mw (20db) to a high powered 400mw
>> (26db) is a 6db increase in output power. So you are saying going from
>> regular to high powered is a double in coverage size?
>> Doesn't increasing the power output at the AP only increase how loud the
>> AP can "shout" which in term dictates how far the receiver can hear from?
>> If the client can't shout back does this do any good?
>>
>> Most client devices today like iPads, Smartphones, and some laptops
>> can't be modified to increase their antenna gain or power output. So the
>> only option is to increase the numbers of APs, or the transmit
>> power/antennas at the AP right?
>>
>> On Thu, Nov 13, 2014 at 12:25 PM, Jack Unger <[email protected]> wrote:
>>
>>> To double the communications distance (everything else holding steady)
>>> requires an additional 6 dB. Knowing this, you can do the math with the
>>> various antenna gains and power levels to determine performance.
>>>
>>> Regards,
>>>
>>> Jack Unger
>>> WISPA FCC Technical Consultant
>>>
>>>
>>> On 11/13/2014 10:15 AM, Colton Conor wrote:
>>>
>>> We are comparing multiple SOHO routers and modems that have the same
>>> Broadcom chipsets. All of them have 802.11N 2x2 configuration. The only
>>> differences between them are if they have internal or external antennas and
>>> the gain of the antennas (either 2, 3, or 5dbi ratings). In addition, some
>>> sell a high powered wifi radio (400mw) while others have the basic (100mw).
>>>
>>> How much a difference does each of these hardware features make in
>>> overall wifi performance?
>>>
>>>
>>> _______________________________________________
>>> Wireless mailing
>>> [email protected]http://lists.wispa.org/mailman/listinfo/wireless
>>>
>>>
>>> --
>>> Support Honest Gil Fulbright for Senate<http://honestgil.com/#up>
>>> <http://honestgil.com/#up>
>>>
>>> Jack Unger - President, Ask-Wi.Com, Inc.
>>> Author (2003) - "Deploying License-Free Wireless Wide-Area Networks"
>>> Serving the WISP Community since 1993760-678-5033 [email protected]
>>>
>>>
>>>
>>> _______________________________________________
>>> Wireless mailing list
>>> [email protected]
>>> http://lists.wispa.org/mailman/listinfo/wireless
>>>
>>>
>>
>>
>> _______________________________________________
>> Wireless mailing
>> [email protected]http://lists.wispa.org/mailman/listinfo/wireless
>>
>>
>> --
>> Support Honest Gil Fulbright for Senate<http://honestgil.com/#up>
>> <http://honestgil.com/#up>
>>
>> Jack Unger - President, Ask-Wi.Com, Inc.
>> Author (2003) - "Deploying License-Free Wireless Wide-Area Networks"
>> Serving the WISP Community since 1993760-678-5033 [email protected]
>>
>>
>>
>> _______________________________________________
>> Wireless mailing list
>> [email protected]
>> http://lists.wispa.org/mailman/listinfo/wireless
>>
>>
>
> _______________________________________________
> Wireless mailing list
> [email protected]
> http://lists.wispa.org/mailman/listinfo/wireless
>
>
--
Ben West
http://gowasabi.net
[email protected]
314-246-9434
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