low data rate in WDS mode

Post new topic   Reply to topic    DD-WRT Forum Forum Index -> Broadcom SoC based Hardware
Author Message
cpresto
DD-WRT Novice


Joined: 01 Aug 2006
Posts: 17

PostPosted: Thu Sep 07, 2006 14:44    Post subject: low data rate in WDS mode Reply with quote
Hi all,
I've a problem regarding data rate with two WRT54GL v1.1 with DD-WRT v23 SP2 (08/30/06) std.

WRT#1<---->WRT#2

Configuration is identical for both of them: AP, WDS, CH1, power 125mW, WPA-PSK-AES key interval 3600sec, transmission rate auto.
Signal is very good, -52 at both ends on a 4Km link, and there are no RX/TX errors:
WRT#1
Received (RX)1175357 OK, no error
Transmitted (TX)1265502 OK, 3149 errors
WRT#2
Received (RX)1346685 OK, no error
Transmitted (TX)1237950 OK, 4515 errors

It seems that there is no interference, because of no Tx/Rx errors.

Despite all the above, the two WRTs connects at a data rate of only 5.5Mbps Confused , and the link net throughput is 2,3Mbps. If I try to "force" 11Mbps or higher, errors occours and net throughput goes down.

What could be the reason for such a behaviour? Question Question Confused

Rgds
Sponsor
cpresto
DD-WRT Novice


Joined: 01 Aug 2006
Posts: 17

PostPosted: Mon Sep 11, 2006 16:07    Post subject: low data rate in WDS mode Reply with quote
Any advice about the post?!?! Question Exclamation Question Exclamation
rolothree
DD-WRT User


Joined: 17 Jul 2006
Posts: 96
Location: Austin, Texas USA

PostPosted: Mon Sep 11, 2006 17:58    Post subject: Reply with quote
Try moving 'Beacon' down to 50 (Wireless Advanced), and

'Sensitivity Range (ACK Timing)' to 0 (Wireless Basic).
wlan
DD-WRT User


Joined: 07 Jun 2006
Posts: 181
Location: BULGARIA

PostPosted: Mon Sep 11, 2006 18:03    Post subject: Reply with quote
rolothree wrote:
Try moving 'Beacon' down to 50 (Wireless Advanced), and

'Sensitivity Range (ACK Timing)' to 0 (Wireless Basic).


Try another channel - like 12 or 13.

_________________
WZR-G300N -DD-WRT v24 Beta (08/15/07) std
WRT54GL - Tomato 1.13
WAP54G v2 - v24 RC-5 micro
WHR-G54S - Tomato 1.13
WHR-HP-G54 - Tomato 1.13
ndoren
DD-WRT User


Joined: 07 Jun 2006
Posts: 51

PostPosted: Mon Sep 11, 2006 18:27    Post subject: Reply with quote
Along the lines of the last post... You can use channels 12-13 for WDS but your USA wireless clients may not attach.

In addition to the ideas above:

1) run wrtbwlog to find the "cleanest channel"
2) rotate and/or tilt the antennas on one router relative to the other, to maximize the signal and the rate. Rotating one router even 5 degrees can make a big difference.
rolothree
DD-WRT User


Joined: 17 Jul 2006
Posts: 96
Location: Austin, Texas USA

PostPosted: Mon Sep 11, 2006 19:45    Post subject: Reply with quote
Played around with my three routers and about the only setting that dramatically changed speed was transmit power. Anything over 110mw degraded performance.

At 110mw it's 54mps on all routers....140mw went down to 36 mps, over 160mw all over the place on the lower end, at 180mw or more it was barely hanging in.......
rkloost
DD-WRT Guru


Joined: 11 Jul 2006
Posts: 1247
Location: Nijmegen, The Netherlands

PostPosted: Mon Sep 11, 2006 22:14    Post subject: Reply with quote
Try disabling speedbooster
_________________
Firmware: DD-WRT v24 SP1 std
1xWRT150Nv1.1
2xWRT54GLv1.1
2xWRT54GSv1.0
1xWRT54Gv2

In need of WRT54GS <= v3 EU/UK for firmware-debugging purposes. Buffalo's are welcome too! PM me if you have a spare one.
VTCop
DD-WRT User


Joined: 12 Jun 2007
Posts: 82

PostPosted: Mon Jul 07, 2008 11:19    Post subject: Reply with quote
Do you have some amplifier between router and antena?

-52 is a very good signal in a 4Km link

What antena are you using?

You have open a topic, you must reply

Regards
GeeTek
DD-WRT Guru


Joined: 06 Jun 2006
Posts: 3770
Location: I'm the one on the plate.

PostPosted: Mon Jul 07, 2008 14:29    Post subject: Reply with quote
Your problem is the ACK timing. Reflash with DD-WRT V23 SP1 and set the ACK to the correct values. You will link at about 48 Mbps with a -52 signal.
_________________
http://69.175.13.131:8015 Streaming Week-End Disco. Station Ripper V 1.1 will do.
VTCop
DD-WRT User


Joined: 12 Jun 2007
Posts: 82

PostPosted: Mon Jul 07, 2008 17:54    Post subject: Reply with quote
Quote:
Reflash with DD-WRT V23 SP1 and set the ACK to the correct values.


Why V23 SP1 ????
In v24 final there is an option for ACK timing too. Dont works this option in v24 final?

Thanks geek
GeeTek
DD-WRT Guru


Joined: 06 Jun 2006
Posts: 3770
Location: I'm the one on the plate.

PostPosted: Mon Jul 07, 2008 21:05    Post subject: Reply with quote
VTCop wrote:
In v24 final there is an option for ACK timing too. Dont works this option in v24 final?

I don't know. I have not had a chance to test it Sad

_________________
http://69.175.13.131:8015 Streaming Week-End Disco. Station Ripper V 1.1 will do.
VTCop
DD-WRT User


Joined: 12 Jun 2007
Posts: 82

PostPosted: Tue Jul 08, 2008 8:20    Post subject: Reply with quote
How could I test this option in v24 final?

For instance, if I have a 5Km link and I put ACK timing to 1000, I must receive too much Tx errors, isn't it?

Then, if I set the ACK timing to 5000 (or more) I mustn't have any Tx error (or only a few), isn`t it?

Some other way to try this?

Sorry if I confused and Im mistaken to someone.
GeeTek
DD-WRT Guru


Joined: 06 Jun 2006
Posts: 3770
Location: I'm the one on the plate.

PostPosted: Tue Jul 08, 2008 8:58    Post subject: Reply with quote
VTCop wrote:
Some other way to try this?

That is the way. You do not need to experiment. You need to set the ACK timing value for the correct distance plus about 5%. When you have the correct value then your data delivery rate will be the same as when you have a local link. It will only be limited by your signal strength and signal to noise ratio. I use Q-Check to test my links for proper power settings and ACK timing.

If you are using the Buffalo WHR-HP-G54 model of radio you should enable the receiver pre-amp with board flag settings of 0x2758. I use these same radios for my 4 mile WDS link and enabling the pre-amp gives about 12 dB of RX boost and a higher connection rate.

http://www.ixiacom.com/products/performance_applications/pa_display.php?skey=qcheck

_________________
http://69.175.13.131:8015 Streaming Week-End Disco. Station Ripper V 1.1 will do.
VTCop
DD-WRT User


Joined: 12 Jun 2007
Posts: 82

PostPosted: Tue Jul 08, 2008 11:11    Post subject: Reply with quote
Thanks very much, I didn`t know Q-Check, but I think that this software will help me a lot.

Quote:
you should enable the receiver pre-amp with board flag settings of 0x2758


Enable the pre-amp, Doesn`t increase the SNR?

Thanks
GeeTek
DD-WRT Guru


Joined: 06 Jun 2006
Posts: 3770
Location: I'm the one on the plate.

PostPosted: Tue Jul 08, 2008 11:57    Post subject: Reply with quote
VTCop wrote:
Enable the pre-amp, Doesn`t increase the SNR?

Thanks

It actually decreases the signal to noise ratio. In other words, it will add a small amount of noise to the signal that was not in the signal before. In most cases the benefit of improving your own signal results in a higher link rate and better data quality. Remember that all radio receivers are already a string of high gain amplifiers in series. That is what a radio is, one big string of amplifiers and frequency converters. The HP model simply has an extra booster stage that other radios do not have. That is exactly why you need to use Q-Check to see how much bandwidth your link can carry, and then start tuning your radio system and ACK value for optimal throughput.

_________________
http://69.175.13.131:8015 Streaming Week-End Disco. Station Ripper V 1.1 will do.
Display posts from previous:    Page 1 of 1
Post new topic   Reply to topic    DD-WRT Forum Forum Index -> Broadcom SoC based Hardware All times are GMT

Navigation

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum