A question for all you EV-DO experts

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grant_k

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#13984 9-Jun-2007 00:24

Tonight I have been doing some testing of the Sierra Wireless 595 AirCard which Mauricio has very kindly loaned to me.

Here is a typical Speedtest result obtained with this card:

Sierra Wireless AirCard 595 Speedtest

* Latency is not wonderful, but OK.
* Download Speed is excellent, no problems there.
* However, 48kbps is the best Upload Speed I got from several tests.

While using this connection to browse the web (including posting to Geekzone), performance is pretty good, but the 48kbps upload speed pretty much kills outgoing Skype audio. Incoming audio however is fine.

If I switch the laptop to WiFi without making any other changes, it connects to my Kordia Extend Wireless 512kbps Down/128kbps Up connection and Skype works perfectly in both directions.

The Sierra Wireless "Watcher" software shows 3 out of 5 bars for signal strength (-89dBm EVDO) and it also shows that an EVDO High-speed Data Session is in use.

Therefore, so far as the 595 AirCard is concerned, the connection to Telecom's T3G network appears to be working as expected.

So, my questions are:

Why is the Upload Performance so poor when the Download Speed is so good?

Because I am getting a 1Mbps Download Speed, I would have thought this means I am using an EVDO Rev.A signal. Is this correct?

Any suggestions would be appreciated, and meanwhile: Many Thanks once again Mauricio for loaning me this card, it's a very cool piece of kit

UPDATE: Just tried another speed test as follows:

Faster Speed Test

The Upload Speed seems to vary quite widely depending on exactly when I run the test. Could other network activity (from other users in the local vicinity) be affecting this?

On the strength of this much improved result, I tried Skype again, and sure enough, the Outgoing Audio was much better although some dropouts were still evident.

It's strange that the Upload Speed is so variable, whereas Download is consistently above 1Mbps which is pretty damn good for mobile broadband

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inquisitor

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#74066 9-Jun-2007 06:42

The slow upstream is an inherent technological problem of EV-DO, as EV-DO is very sensibile to increasing signal attenuation. A lot of Verizon customers have complained especially about the upload bandwidth, but there's no solution execept for going outdoors or getting an external antenna.
Whereas the antennas of the basestations are located at elevated positions and so provide a good signal dispersion, your data card with it's tiny antenna is in a way worse situation. Also the signal power of the basestation is much higher than your data card's. That's why upload speed suffers more from obstacles and the distance between data card and basestation than in the opposite direction.
By the way if you initiate a data session with 1XRTT and move to a EV-DO-covered site, you won't get EV-DO speed, as soft handovers from 1XRTT to EV-DO don't work (at least that was the case last year with Verizon).

You could approach to an EV-DO capable basestation and see how upstream improves or just wait for Telecom to roll out UMTS850, which could provide an upstream bandwidth of up to 5.8 MBit/s (if HSUPA is implemented) and will still serve almost full data rates even when reception is low, as UMTS is significantly less sensible to signal attenuation.

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sbiddle

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#74067 9-Jun-2007 06:48

inquisitor:
You could approach to an EV-DO capable basestation and see how upstream improves or just wait for Telecom to roll out UMTS850, which could provide an upstream bandwidth of up to 5.8 MBit/s (if HSUPA is implemented) and will still serve almost full data rates even when reception is low, as UMTS is significantly less sensible to signal attenuation.

That could be a long wait. Telecom's 850MHz network is only going to be GSM/EDGE.

freitasm

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#74078 9-Jun-2007 08:57

I would say is something with this specific cell site or the distance you have to it. Using this same Sierra Wireless Aircard you borrowed from me, I got this in my first speed test:

Now, note that you can only get those speeds if you are connecting to CDMA EVDO Rev A. CDMA EVDO Rev 0 should be providing different results of course, but not as low as that...

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sbiddle

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#74081 9-Jun-2007 09:07

How far away from a Telecom cellsite are you?

Jama

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#74083 9-Jun-2007 09:14

Where are you? It looks like you are connected to Rev0 which is max 153kbps upload and the latency is not as good as RevA.

Don't listen to the Inquisitor troll he is talking through a hole in his ****. 1xRTT hands up to EVDO when the card is dormant.

grant_k

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#74086 9-Jun-2007 09:35

sbiddle: How far away from a Telecom cellsite are you?

I think we are connected via a site on the Waikino Peninsular which is about 6km across the water from us. This is near to Opua in the Bay of Islands.

Thanks Jama, it does indeed look as though I am connected to a Rev.0 cellsite. That would explain the slow Upload Speed. However I'm still surprised that Download Speed is so good.

It doesn't really matter too much if we get poor performance here, I just tried out of interest to see if T3G is a viable replacement for other forms of broadband in our area.

Hopefully at the Mystery Creek Fieldays next week it will be a lot better because the terrain down there is pretty much completely flat except for the exhibition site itself which is down in a bit of a dip. The camping area though is up on the flat so we should get an excellent signal there.

I tried again up the other end of our house holding the laptop right in front of a window to see if that made any difference. Actually, it was much worse -- the signal dropped to 2 bars (-99dBm) and the speeds dropped to about half as well.

By wandering around outside the house and holding the laptop up in the air away from me I did manage to get 4 bars of signal for a moment (-87dBm) but the speed of about 1100k Down / 60k Up is still about as good as I can get this morning.

Thanks everyone for your replies.

juha

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#74092 9-Jun-2007 11:14

The new 595 cards go much faster than the previous 580s, I've found. Double the download speed at similar signal strengths. I don't know what improvements Sierra made to the 595s.

Juha

inquisitor

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#74096 9-Jun-2007 11:54

Don't listen to the Inquisitor troll he is talking through a hole in his ****. 1xRTT hands up to EVDO when the card is dormant.

Before using infantile language you should keep reading my posts until you've gotten every single word. If you fail ask Mommy to read it for you.
Firstly I explicitly wrote about soft handovers - that means during an active session without interrupting that session. Actually soft handovers work, but the EV-DO site will keep using 1xRTT speed until you disconnect and reconnect to the EV-DO site. Further I made clear, I'm talking about my experience on the Verizon network during 2006. If you doubt that soft handovers from 1xRTT to EV-DO didn't work then in terms of bandwidth increase, convince yourself by a Google search!

By wandering around outside the house and holding the laptop up in the air away from me I did manage to get 4 bars of signal for a moment (-87dBm) but the speed of about 1100k Down / 60k Up is still about as good as I can get this morning.

Was there an active session when you made your outdoor testing? You shouldn't start a session before you're outdoors and have waited for a moment, since your datacard probably won't negotiate higher speeds during an active session. Beyond that, your datacard may require the signal improvement to hold on for a while before it negotiates a higher bandwidth - so wait 30 seconds or so before connecting after going outside.

paradoxsm

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#74098 9-Jun-2007 11:55

EVDO is fantastic in rural/outlying areas.

I have uesd it many time where there should be "no coverage" and it seems Telecom are rather honest about coverage, when they indicate coverage, there will be a clean,. strong signal

The saddest part for EVDO is where I live and work in ellerslie, it's utterly diabolical. UMTS is not any better but HSDPA works great here..

I'm unsure why, as everywhere elese from cities, bult-up residential areas and the "sticks" EVDO is almost flawless.. AND I was using a harrier PDA which is probably the worst modem I could use and got good results so the dedicated datacards should be awesomely fast.

You shoule be pleasantly suprised and i'll be down there too with some devices doing a bit of Waikato testing for a project.

Loftus

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#74106 9-Jun-2007 13:50

A little knowledge is a dangerous thing...

inquisitor: Firstly I explicitly wrote about soft handovers - that means during an active session without interrupting that session. Actually soft handovers work, but the EV-DO site will keep using 1xRTT speed until you disconnect and reconnect to the EV-DO site. Further I made clear, I'm talking about my experience on the Verizon network during 2006. If you doubt that soft handovers from 1xRTT to EV-DO didn't work then in terms of bandwidth increase, convince yourself by a Google search!

Let's be clear about the terminology: SOFT handovers are "make before break", they allow simultaneous communication between multiple sites/antennas/transmitters. HARD handovers are "break before make", the connection is terminated before being re-established on a new site/antenna/transmitter/technology.

Handoffs between EVDO and CDMA2000 are HARD handoffs (as are UMTS -> GSM handoffs, and of course all GSM handoffs are HARD). It would help if you didn't confuse the discussion with incorrect terms.

Back on Topic....

I think Grant17 should definately give TNZ's customer service a call and pester them for detail about if/when his area will be upgraded from Rev0 to RevA. In the meantime I'd encourage you to keep using the existing EVDO service as much as you can, because we keep track of which sites have the highest usage - as they make strong candidates for any upgrades.

EVDO is fantastic in rural/outlying areas.

Yeah, EVDO speeds are typically interference-limited, so providing you have at least some sort of EVDO coverage and no interference from other sites, then the throughput is pretty decent. It's nice to see rural & provincial users get a break for a change :)

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#74110 9-Jun-2007 14:17

freitasm:

If only I could get those sort of speeds over ADSL

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#74115 9-Jun-2007 15:50

I find regular EVDO is quite good, though rev A is always nice.

As an added bonus - 1X is a much nicer fallback than GPRS which is like being put on 14.4kbps dial up connections/Go Large type plans.

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nzbnw

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#74130 9-Jun-2007 18:37

Grant if your are using the Sierra Wireless AirCard Watcher it will detail if you are in an EVDO or EVDO RevA coverage area.

nzbnw

grant_k

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#74132 9-Jun-2007 19:42

nzbnw: Grant if your are using the Sierra Wireless AirCard Watcher it will detail if you are in an EVDO or EVDO RevA coverage area.

Yes I am certainly using the Sierra "Watcher" software. I downloaded the very latest version as per the instructions on Telecom's web site before starting to use the 595 card.

Watcher reports an "EVDO" signal without any mention of Rev.A, so I guess that means I am running Rev.0.

I will see if this changes once we get to Hamilton on Tuesday night.

Thanks again guys

nzbnw

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#75601 22-Jun-2007 00:14

So Grant, how did you find EVDO and more importantly did you get to experience EVDO Rev A?

nzbnw

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