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.
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.
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
Chris Williams clw7500nc@gmail.com
The new 802.11 standards actually use OFDM already.
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.
I don't see why OFDM is getting treated like some new tech holy grail. 802.11a and g both use it, and have for a very long time.
My sig is blank, I typed this by hand.
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.
retrorocket.o not found, launch anyway?