802.11a uses 5GHz. 802.11b uses 2.4GHz. Lower frequencies go through walls better.
-----Original Message----- From: Ivan Korshun [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 30, 2003 11:45 AM To: [EMAIL PROTECTED] Subject: Re: [BAWUG] 802.11b Long Range non line of sight I made measurements of threshold sensitivity for SmartBridges, it [EMAIL PROTECTED] !!! I was very much surprised with this outcome and naturally multiply has verified. Usual Prism 2.5 PC card has -84 [EMAIL PROTECTED] and -94 [EMAIL PROTECTED] And why 802.11a (OFDM) PC card not work through a wall where 802.11b (DSSS) PC card without problems. It was supervised very many people. -Ivan > > Our own 802.11b is 24dBm at the antenna port of the ODU and real 11Mbps > sensitivity of -85dBm (system wide, not just the chip), which is a full 2 > dBm better than SmartBridges (11Mbps has -83dBm sensitivity and 1Mbps has > -92dBm per their data sheet > http://www.smartbridges.com/new/products/appo.php). I don't see any > "threshold sensitivity" numbers listed for SmartBridges > > As for OFDM, the average sensitivity at 6Mbps specific to the BreezeACCESS > VL is -92dBm with a minimum number of -88dBm at 6Mbps. > > - Patrick > > -----Original Message----- > From: Ivan Korshun [mailto:[EMAIL PROTECTED] > Sent: Wednesday, July 30, 2003 10:29 AM > To: [EMAIL PROTECTED] > Subject: Re: [BAWUG] 802.11b Long Range non line of sight > > line of sight 802.11b, > > L=64km, 11M, transfer 492KBYTE/sec (FTP) !!!!!!!!!!!!! > > DSSS device like SmartBridges > have threshold sensitivity Rx = -102dBm. > > What threshold sensitivity devices OFDM ? > > -Ivan > > > > > Fair enough Jim. I'll relate details once provided by customers. Until > then, > > here is one such paper though that does provide some math and photos > > relative to trials of some of our OFDM early on. > > > http://www.alvarion-usa.com/RunTime/Materials/KnowledgePoolFiles/alv_OFDM%20 > > wp.pdf > > > > - Patrick > > > > -----Original Message----- > > From: Jim Thompson [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, July 30, 2003 7:14 AM > > To: Patrick Leary > > Cc: [EMAIL PROTECTED] > > Subject: RE: [BAWUG] 802.11b Long Range non line of sight > > > > You're making my point, but may not understand 'why'. Some of the > > deployment > > scenerios you describe are extremely difficult, and changing > > modulation may not be enough (heavy understatement). > > > > I only became sarcastic when you started asserting some 'magic' to > > OFDM over single-carrier (or spreading) systems. Most technologies > > have trade-offs. OFDM deals well with delay spread up to the limit of > > the GI, and then it fails due to massive, overwhelming ISI. > > > > RF is physics. Physics is mostly math. Modulation is math. You > > offered emperical data as 'proof', but proofs require mathematics. > > > > Being completely open, I'm sure your product works in an interesting > > number of scenerios. Really. I hope you sell a ton. > > > > But in the end propagation is physics, and "you canno violate the laws > > of physics, captian." > > > > The emperical data you've offered are short textual descriptions of > > deployments. I'm interested either in the modeling (or measurements) > > that show your product works, or in the actual data from the > > deployments you describe. > > > > OK? > > > > Jim > > > > Patrick Leary writes: > > > All things "fail" when used beyond their capabilities and/or intent, so > I > > > don't regard such things as failures of the technology so much as > failure > > of > > > the human implementing it. For example, would you be the type to drive a > > car > > > into a lake, then call the car's inability to reach the other side a > > failure > > > of the product? > > > > > > Jim, the larger point is that your sarcasm is unwanted and unwarranted. > I > > > see now how you respond once your intellectual arguments themselves > fail. > > > You switch to personal insult. Accordingly, my dialogue with you has > > ended. > > > Enjoy your "last word" - no doubt you are the kind who must have it. > > > > > > - Patrick Leary > > > > > > -----Original Message----- > > > From: Jim Thompson [mailto:[EMAIL PROTECTED] > > > Sent: Monday, July 28, 2003 3:56 AM > > > To: Patrick Leary > > > Cc: [EMAIL PROTECTED] > > > Subject: RE: [BAWUG] 802.11b Long Range non line of sight > > > > > > > > > > > > I'm sure you have many successful deployments. I'm sure your products > > > are all winners, and your shareholders think you walk the earth in > > > peace. > > > > > > I'm interested in where things fail(ed), and 'why'. > > > > > > Jim > > > > > > Patrick Leary writes: > > > > Fair enough, so here is a list of a few of the areas where we tested > > > and/or > > > > have implemented OFDM in scaled deployments so far: > > > > - extremely urban-type low building density of a major city in South > > > America > > > > - heavily foliated coastal hills, across bays, and urban settings in > New > > > > Zealand > > > > - low mountains with heavy deciduous tree coverage in rural western > > > Maryland > > > > - coastal Southern California with little vegetation > > > > - flat arid, with marginal density in the Texas Panhandle > > > > - heavily foliated and urban landscapes in Hungary > > > > - deep in the very heavy coniferous high mountains in rural British > > > Columbia > > > > in Canada > > > > - an urban landscape in the Russian steps > > > > > > > > I'd say this is a fairly strong cross section of environments. Have > any > > > more > > > > negatives you might like to guess about on things you have never seen? > > > > > > > > Patrick Leary > > > > Alvarion > > > > > > > > -----Original Message----- > > > > From: Jim Thompson [mailto:[EMAIL PROTECTED] > > > > Sent: Friday, July 25, 2003 3:41 AM > > > > To: Patrick Leary > > > > Cc: 'Tim Pozar'; Ladjicke Diouf; [EMAIL PROTECTED]; > > > > [EMAIL PROTECTED] > > > > Subject: RE: [BAWUG] 802.11b Long Range non line of sight > > > > > > > > > > > > > > > > Empirical data can only demonstrate results in the environment you > > > > studied. > > > > > > > > Proofs require mathematics. > > > > > > > > Patrick Leary writes: > > > > > 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. > > > > > > > > > > Patrick > > > > > > > > > > -----Original Message----- > > > > > From: Tim Pozar [mailto:[EMAIL PROTECTED] > > > > > Sent: Thursday, July 24, 2003 8:27 PM > > > > > To: Ladjicke Diouf > > > > > Cc: Patrick Leary; [EMAIL PROTECTED]; > [EMAIL PROTECTED] > > > > > Subject: Re: [BAWUG] 802.11b Long Range non line of sight > > > > > > > > > > > > > > > On Thu, Jul 24, 2003 at 02:26:26PM -0700, Ladjicke Diouf wrote: > > > > > > Can somebody shed some light on how OFDM helps NLOS, I thought it > > was > > > > just > > > > > > > > > > > a coding scheme like DSSS for 802.11b > > > > > > > > > > You still need LOS. OFDM of DSSS will handle interference (ie. > > > > > "smearing" ) of the signal better with the lower symbol rate. > Things > > > > > like multipath will be less of an issue. Still an issue, but less > > > > > pronounced. > > > > > > > > > > Tim > > > > > -- > > > > > Snail: Tim Pozar / LNS / 1978 45th Ave / San Francisco CA 94116 / > > USA > > > > > POTS: +1 415 665 3790 Radio: KC6GNJ / KAE6247 > > > > > "Be who you are and say what you feel because the people who mind > > > > > don't matter and the people who matter don't mind." - Dr. Seuss > > > > > > > > > > > > > > > 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) > > > > > > > > > > > > > > > > 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. > > > > > > > > > > **************************************************************************** > > > > ******** > > > > > > > > > > -- > > > "Speed, it seems to me, provides the one genuinely modern pleasure." > > > -- Aldous Huxley (1894 - 1963) > > > > > > > > > > > > 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) > > > > > > > > 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 > -- > general wireless list, a bawug thing <http://www.bawug.org/> > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > > > 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 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
