Mon, 17 May 2004

Fun with CDMA2000
I bought a SprintPCS Vision Connection Card last week. This device uses CDMA 2000, 1xRTT specifically. As documented earlier, I can squeeze quite a bit out of this network.

First Impressions

The Merlin C201, in PCMCIA form-factor, looks almost like an Orinoco Gold. And like most WiFi cards, it is cross-polarized with the system it connects to. Other Sprint cards make use of vertical antennas, I am not entirely sure why Novatel went with this lame design. It was the cheapest of the 4 cards featured -- a mere $199 dollars, usually brought down in price by carrier subsudy. I paid $150 with my business discount and 1 year of service contract.

As expected, throughput is quite nice. I average about 100kbps up and down, without the aid of compression. It works just as well at 80mph as it does at 0mph...with a few exceptions. Moving from good coverage to bad coverage is one of them....

More Streaming Fun

With the help of Matt Wilson, I decided to put 1xRTT to the test: Stream live video FROM the mobile device; at 60mph; during rush hour.

Results of Dual ISDN (Actual: 90Kbps)

While in motion, the stream would go maybe a minute or two before chopping. After a little chopping, it started right up again. After a little tweaking with the connection medium (TCP or UDP), I determined that if the coverage dropped bellow 3 bars, sending 90Kbps of payload just was not going to happen. We don't have much head room for error if the coverage heads south. I suspect this will only work well in fixed operations, or with a good antenna to ensure signal strength is optimum.

Results of Single ISDN (Actual: ??Kbps)

"Single ISDN" would likely be a 64Kbps circuit. While this gave us more head room than Dual ISDN, we'd occasionally have a bit of break up in poor coverage areas.

Results of 28k to 56k (Actual: 20-34Kbps)

We were able to keep a stream going for a considerably long time (>10 minutes), even with 2 bars of signal. It seems that no matter what happened, it still pounded through.

Final Thoughts

While more testing will likely ensue, 1xRTT definately has a very nice upload that does not compare to anything else available. It will stay that way until UMTS (WCDMA GSM) or CDMA2000 Ev-Dv makes its way into the world. Note that while Ev-Do brings us over 2Mbps of download, it does not help our upload much. So Verizon's impact will be minimal this summer.

It also is very fun to note that 1xRTT has been available in every CDMA coverage area since Vision launch in the summer of 2002...which is just about everywhere.

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