Your response is little more than hype. Just tell us your GI. That will mostly dictate how far you can go in a high delay spread deployment with low interference.
Jim Patrick Leary writes: > I could not agree more Cliff. Your points about 802.11g explain a key > distinction regarding what is intended for indoor use and what must be > enabled to work successfully in the outdoor environment. All our systems, > and the OFDM is no different, is optimized for outdoor environments. That > includes environmentals, timing, authentication, security, as well as > adjustiong the OFDM modulation for multipath conditions resulting from > miles, not feet. > > I am not sure about the specific numbers you have requested so I have sent > off a mail to get them. When I have my reply, I'll share them. > > Regards, > > Patrick > > -----Original Message----- > From: Cliff Skolnick [mailto:[EMAIL PROTECTED] > Sent: Thursday, July 24, 2003 11:31 PM > To: Patrick Leary > Cc: 'Tim Pozar'; Ladjicke Diouf; [EMAIL PROTECTED]; > [EMAIL PROTECTED] > Subject: Re: [BAWUG] 802.11b Long Range non line of sight > > > Theory is great, but in practice I've had problem with OFDM as > specified for 802.11g. Depending on how you tune your gear multipath > can kill you, but timings can be adjusted to handle it well, even use > it. I've not experienced this personally as I've only use 802.11a and > 802.11g indoors, but I've heard stories. > > The biggest problem which I have totally experienced is the current > lack of adjacent channel rejection for OFDM of the current generation > for adjacent yet non-overlapping channels (1, 6, 11). I was involved > with a large roll out a will tons of 802.11b on 1 and 11, and the > 802.11g on 6. The 802.11g was getting beat up performance wise so we > looked into it. The numbers I was quoted were a 30db rejection for > 802.11b (orinoco gear) and a < 6db rejection (I'm being nice here) for > linksys and other G cards. Next time we will pick 1 or 11 for the > 802.11g gear :/ > > What kind of adjacent channel rejection does your gear have? and have > you adjusted your OFDM timings to handle multipath where the bit shift > is larger than 802.11g? So far I've not been impressed with the > stability of 802.11a or 802.11g gear, but I think the issues were not > OFDM's fault, more implementation issues. > > Cheers, > Cliff > > > > On Thursday, Jul 24, 2003, at 19:45 US/Pacific, Patrick Leary wrote: > > > Tim, your understanding of OFDM is way off. Extraordinarily stability > > is > > achieved with OFDM - far more than with our FHSS or our DSSS. We have > > examples of links having only a single packet error over several > > weeks. I am > > not basing these off theory, but off actual field results both beta and > > commercial deployments. Here is a link to some such tests done using > > our > > 3.5GHz OFDM PMP which has been shipping for 18 months and is in use in > > major > > carrier deployments around the world. This paper includes detailed > > photo > > examples of the links. > > > > http://www.alvarion-usa.com/RunTime/Materials/KnowledgePoolFiles/ > > alv_OFDM%20 > > wp.pdf > > > > Keep in mind, this is 3.5GHz equipment > > http://www.alvarion-usa.com/RunTime/ > > Products_2020.asp?tNodeParam=33working > > off a very small channelization, so the max data rate is lower than > > our same > > products using 20MHz 5GHz channels (BreezeACCESS VL and BreezeACCESS > > LB). > > VL: http://www.alvarion-usa.com/RunTime/Products_2020.asp?tNodeParam=39 > > LB: http://www.alvarion-usa.com/RunTime/Products_2020.asp?tNodeParam=35 > > > > Patrick > > Alvarion > > > > > > > > -----Original Message----- > > From: 'Tim Pozar' [mailto:[EMAIL PROTECTED] > > Sent: Thursday, July 24, 2003 8:43 PM > > To: Patrick Leary > > Cc: Ladjicke Diouf; [EMAIL PROTECTED]; [EMAIL PROTECTED] > > Subject: Re: [BAWUG] 802.11b Long Range non line of sight > > > > > > On Thu, Jul 24, 2003 at 05:32:38PM -0700, Patrick Leary wrote: > >> Tim, I am not sure if you are talking about OFDM or DSSS. With OFDM, > >> you > >> DON'T need LOS. Of course its not going to connect forever with NLOS, > >> but > >> for a few miles, it is a no brainer. We have ample empirical data that > >> proves it. > > > > I haven't see your report but if you are basing it on using things > > like knife-edge diffraction or even multipath as your method of > > getting from point A to point B. I *would* be cautious about giving > > the link a high "up-time". > > > > Looking forward to the report... > > > > Tim > > > > > > This mail passed through mail.alvarion.com > > > > *********************************************************************** > > ***** > > ******** > > This footnote confirms that this email message has been scanned by > > PineApp Mail-SeCure for the presence of malicious code, vandals & > > computer > > viruses. > > *********************************************************************** > > ***** > > ******** > > -- > > general wireless list, a bawug thing <http://www.bawug.org/> > > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > > > -- > "Capitalism is the astounding belief that the most wickedest of men > will do the most wickedest of things for the greatest good of everyone." > - John Maynard Keynes > > > > This mail passed through mail.alvarion.com > > **************************************************************************** > ******** > This footnote confirms that this email message has been scanned by > PineApp Mail-SeCure for the presence of malicious code, vandals & computer > viruses. > **************************************************************************** > ******** > -- > general wireless list, a bawug thing <http://www.bawug.org/> > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > -- "Speed, it seems to me, provides the one genuinely modern pleasure." -- Aldous Huxley (1894 - 1963) -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
