[opendtv] No surprise, Telia's LTE not as fast as promised

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Tue, 26 Jan 2010 17:10:29 -0600

It seems that getting truth through hype is ever so difficult. The truth of the 
matter is that in terms of spectral efficiency, the 3G WDCMA (HSPA+ or 
equivalent cdma2000 EV-DO schemes) and 4G LTE are no different. So if you 
aggregate WCDMA channels together to achieve the same channel bandwidths as 
LTE, you will achieve the same bit rates.

Typical WCDMA channels today are either 3.75 (cdma2000, made up of three 1.25 
MHz narrowband CDMA carriers), or 5 MHz wide. If you increase those to 10 or 20 
MHz, and increase the constallation, you'll get the same 100+ Mb/s 
theoretically possible with LTE. This is not just theoretical. It's in the 
development pipeline. WCDMA and cdma2000 started at 2 Mb/s peak. They are now 
achieving 28.8 Mb/s peak. And they are on their way to over 150 Mb/s.

The difference is, if you stay with WCDMA schemes for the RF links, the same 
spectrum could in principle be shared by what we call 2G (except GSM), 3G, and 
4G devices. Of course, you still need additional spectrum to serve the really 
fast 4G devices, but at least it would not represent an entirely new chunk of 
spectrum usable *only* by 4G devices.

So if the FCC is so concerned about running out of spectrum, they should look 
into mandating more effective use of 2G, 3G, and 4G spectrum, all of which is 
well within the state of the art. Instead of allowing all the unnecessarily 
incompatible schemes to coexist. It wasn't until June of 2008 that the analog 
AMPS frequencies were finally allowed to be reused. Now we are going to have 
the same wasteful transitional period for WCDMA and LTE. Was this really 
necessary? If so, why?

Bert

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http://www.rethink-wireless.com/article.asp?article_id=2543

No surprise, Telia's LTE not as fast as promised
By CAROLINE GABRIEL

Published: 26 January, 2010

There is always a yawning gap between the peak or theoretical data rates 
promised for new wireless technologies, and their real world performance. The 
latest operator to suffer a PR problem because of this is TeliaSonera, whose 
LTE network in Stockholm, the first commercial LTE system in the world, is 
delivering only 12Mbps.

This falls well short of the firm's marketing promises of "up to 50Mbps", 
points out research firm Northstream, which conducted the tests. Northstream 
used a Samsung modem to test the Ericsson network, which runs in 2.6GHz. Upload 
speeds averaged 5Mbps.

At TeliaSonera's launch event, download speeds of over 40Mbps were 
demonstrated, but of course a marketing demo was likely to use the optimal 
position of devices to base stations. Stating the obvious, Northstream CEO 
Bengt Nordström said: "It seems like the capacity drops off fast as the 
distance from a base station increases."

Of course, most 3G networks do not deliver even 1Mbps consistently, and so 
12Mbps may be very welcome to heavy duty users. Indeed, the main issues raised 
by such arguments over real versus peak speeds concern how operators 
communicate with their customers, rather than actual technical performance. 
Some carriers such as Clearwire have taken the high ground by advertising 
average rather than peak data rates for their networks, while European cellcos, 
in particular, have come under mounting pressure from regulators and 
advertising standards bodies to stop misleading consumers by implying that 
maximum data rates are the norm.

This is not the first time that Telia's Stockholm network has come under fire. 
At the end of last year, Huawei claimed that the network it has supplied to 
Telia, in Norwegian capital Oslo, had reached peak download speeds of 96Mbps, 
compared to 44Mbps on the Ericsson system in Sweden. However, the Oslo network 
uses 20MHz of spectrum - the channel size usually assumed when LTE performance 
statistics are quoted, but in reality rarely available to cellcos. By contrast, 
the Stockholm build-out has only the more common 10MHz. The controversy over 
Telia's data rates will revive debate over whether effective 4G deployments 
really do need wide channels.
 
 
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