Siemens Continues OFDM Push

Khoo writes "German telecommunications gear maker Siemens is backing a new kind of broadband wireless technology that will compete with Wi-Fi and 3G cellular services." As we covered recently, speed tests have been up to 360 Mbps and one of the latest rumours is that they will use it in conjunction with VoIP servers. That's unconfirmed, but particularly for new phone deployments, laying no wire would be nice. And Yes, Virginia - ITMJ is part of OSTG, like Slashdot.

Comments

To Clarify:

[Enigma_Man]

ITMJ, part of OSTG reports about OFDM to use VoIP?

Good...

-Jesse

Re:To Clarify:

[Anonymous Coward]

This article is an example that acronyms do not support understanding. OFDM is "orthogonal freqency division multiplexing". In other words, it's a kind of modulation. It does not compete with Wi-fi. 802.11g uses OFDM too.

VoIP for Mobiles is overkill

[Gopal.V]

Of course GSM was digital, YTF couldn't they route those 52 byte voice packets over UDP or something ?. Maybe aggregate them into 1500 byte blocks and push over ethernet or the equivalent with ATM ?.

VoIP works , but I don't see the point for mobiles to run a full IP stack. (oh, yeah I work on a phone with an IP stack and it drains the battery like HELL when in packet services mode).

Re:VoIP for Mobiles is overkill

[gl4ss]

that's exactly the point many people forget when they're hyping up voip for mobiles, that the for _mobile_ use networks already have been tuned for transferring voice as cheaply and well as possible.

(that is, if it really gets cheap enough to build wide coverage other networks they would still have the upper hand- now, they might change gradually into providing general data services rather than clearly seperated voice functionality, but that ain't gonna happen anytime soon totally)

so the ONLY reason to use VOIP over mobile networks would be artificially stupidly twisted pricing structure.

Distance?

[grunt107]

One thing seemilngly always omitted in these 'speed' stories is distance. While a 3x speed increase over 11n - which is 2x better than 11g - is impressive, if the basic assumption that the speeds correlate over the same distance is incorrect, the speed is not all that great. It would take multiple repeater modules to make up for the shortage, limiting its usefulness.

OFDM information

[Mstrgeek]

More onformation on OFDM this site has great information and links plus a forum based on OFDM

http://www.wave-report.com/tutorials/OFDM.htm

What Google Groups is saying about the topic

http://groups.google.com/groups?q=OFDM&hl=en&lr=&s a=N&tab=wg

Not quite as fast as advertised... for now

[Ingolfke]

From the CNET article... "[Flash-OFDM] offers connection rates of 1.5 megabits per second." So the 360Mbps is in the lab, and is not likely to be out of the lab and into your pants (these are cell phones) for several more years. 1.5 Mbps isn't too bad for now though.

Slashdot... news and commentary on par with CBS.

Why mark that as a troll?

[Andy Dodd]

I agree. OFDM isn't some sort of holy grail. It doesn't do anything that somehow invalidate's Shannon's Law for channel capacity, and it is quite possible to come within 0.5 dB of Shannon capacity with other modulation schemes. It's nothing special, just another method for modulation that happens to have certain benefits in some situations. (Examples include higher multipath immunity.) The European DVB-T (Terrestrial Digital Video Broadcast) standard uses OFDM and it's been around for a while (at least five years I think.) As the parent said, 802.11a and g use OFDM also.

OFDM is not a magic bullet. It's also not new.

Yes, Siemens' 360 Mbps number is impressive, but to achieve that performance, they either used some very interesting tricks (OFDM not being the key here, possibly a MIMO multiple-antenna system, a technology that is still under heavy research.), or made tradeoffs (high bandwidth or high SNR requirements) that will make the system useless for real-world deployment.