The key with the train is that we are using directional (fixed) wimax CPEs on the rooftop of the trains with 38 dB total EIRP in both directions. It is near line of sight, but not Line of sight.
We are also testing our own 2.5GHz mobile WiMAX network in Santa Fe, NM and we are getting about 3000ft to indoor mobile clients. We can operate at 47dB (about 100Watts) on the base stations and clients are slightly under 1W total EIRP. This allows us to put 1 base station every 1-3 sq miles, versus our muni WiFi networks where we put about 40 APs per sq mile (as in Miami Beach) and it still did not work great to mobile devices (e.g. needed to add a Ruckus or Pepwave CPE). In any case, what is really needed to make mobile wimax universal is 700MHz WiMAX (e.g. using the remaining Dblock) http://www.andrewseybold.com/commentary.asp?ID=211 Just some thoughts, I just want inexpensive 4G everywhere already. tyler ------- Tyler van Houwelingen Founder & CEO AzulStar, Inc. 1051 Jackson, Grand Haven, MI 49417 Main: 1-877-AZULSTAR Fax: 616-842-1104 www.azulstar.com -------------------------------------------------- From: "Tyler Booth" <[email protected]> Sent: Friday, May 29, 2009 5:55 PM To: <[email protected]> Subject: [ptp-general] Re: SkyPilot Purchased > > > On May 29, 2009, at 8:11 AM, Tyler van Houwelingen wrote: > >> >> The technologies are very similar and With Line of sight for Point >> to point >> links the distances are about the same between the two, in fact WiFi >> may be >> a slightly better technology for Point to Point because you can use >> larger >> channel sizes e.g. 20MHz, 40MHz. That said, for providing last >> mile access >> (e.g. Skypilot business model), it all comes down to how much >> power, how >> low in the frequency spectrum you are operating and what is your >> channel >> width. Thus for access, WiMAX dominates and the signal goes much >> (2-6X) >> farther simply because you have much higher Tx power, smaller >> channel sizes >> (e.g. Clearwire uses 10Mhz channels), absolutely no noise (given >> licensed >> spectrum) and operates lower in the frequency from 450MHz to 3.6GHZ, >> instead >> of 5Ghz like 11a or 2.4 for 11g/n. > > All of Clear's client devices operate between 200mw and 500mw, the > access points > as I understand are limited to about 44db ERIP (~25watts). While the > access points > are certainly putting out more power than you're allowed on WiFi, > we're only talking > about an 8db difference. > >> Clearwire is using a range of about 4000ft for their mobile network, >> whereas >> with metro WiFi you are really looking at 500-750 feet max and you >> still >> have inconsistent coverage. As another example, we are currently >> doing two >> large train broadband projects (putting internet on the trains), one >> with >> 802.11a at 5.4GHz/4.9GHz, one with WiMAX at 3.6GHz. With WiMAX, we >> can get >> by with a tower along the track every 10-15 miles or so, with WiFi, >> we need >> one every 4-7 miles or so. Almost twice the distance with WiMAX, >> for the >> same net throughput. > > Clear is deploying far more densely than 4000ft. They, like the rest > of us, are limited by > the laws of physics and you simply can't push 44db through 3/4 mile of > buildings and trees > at 2.5ghz, it just isn't possible. I have seen their deployment maps > and coverage estimates > here in Portland they are in most places getting about 1000ft of > coverage off a typical tower. > Certainly still much better than you'd expect from mobile WiFi. > > Your train project must either be using giant 100ft towers along a > straight/flat > route. I doubt that the distance in this case has anything to do with > WiFi vs WiMAX, but more > to do with the stack implementation on the specific vendors you're > using. With trains, you need to compensate > for the doppler effect on a moving target. As such, you need a rapidly > adjusting ack timeout. Using > a lower frequency to minimize your fade margin from trees/buildings > will also be beneficial unless you can guarantee > line of sight along the entire length of track. > >> Both WiFi and WiMAX have there pros and cons depending on what you >> are using >> it for and both are great technologies. But for wide area last mile >> mobile >> access, WiMAX is definitely the way to go, Wi-Fi really does not cut >> it. > > Agreed. > > >> >> ------- >> >> Tyler van Houwelingen >> Founder & CEO >> AzulStar, Inc. >> 1051 Jackson, Grand Haven, MI 49417 >> Main: 1-877-AZULSTAR >> Fax: 616-842-1104 >> www.azulstar.com >> >> -------------------------------------------------- >> From: "Michael Weinberg" <[email protected]> >> Sent: Friday, May 29, 2009 8:08 AM >> To: <[email protected]> >> Subject: [ptp-general] SkyPilot Purchased >> >>> >>> This has been reported by a few people, including Mike Rogoway at the >>> Oregonian, but I'm particularly intrigued by a quote in CNET's >>> article >>> (http://news.cnet.com/8301-11128_3-10250943-54.html): >>> >>> "SkyPilots Wi-Fi mesh networking gear has the range of WiMax but is >>> cheaper, said Brian Jenkins, director of marketing for the company. >>> "We take standard chips and make system look like a WiMax in terms of >>> range and capacity," he said." >>> >>> Does anyone actually believe that? If that were the case, I'd expect >>> that the Portland MetroFi deployment would have worked much better. >>> Of >>> course, if that's even half true, then I really would like the City >>> of >>> Portland to take down the gear and put it in the hands of the >>> community to do something with. >>> >>> One possibility is that Jenkins is (somewhat disingenuously) >>> referring >>> to unlicensed, 5GHz WiMax, rather than the expensive licensed stuff >>> ala Clearwire, and happily accepting the public's confusion over >>> WiMax >>> flavors. >>> >>> -- >>> Michael Weinberg >>> President >>> Personal Telco Project, Inc. >>> A 501(c)(3) Non-Profit >>> >>>> >>> >> >> > >> > > > > > --~--~---------~--~----~------------~-------~--~----~ The Personal Telco Project - http://www.personaltelco.net/ Donate to PTP: http://www.personaltelco.net/donate Archives: http://news.gmane.org/gmane.network.wireless.portland.general/ Etiquette: http://www.personaltelco.net/index.cgi/MailingListEtiquette List information: http://lists.personaltelco.net To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] -~----------~----~----~----~------~----~------~--~---
