So, what down converted 802.11a systems are there for 900? ----- Original Message ----- From: "Charles Wu" <[EMAIL PROTECTED]> To: "WISPA General List" <wireless@wispa.org> Sent: Thursday, July 17, 2008 9:19 PM Subject: Re: [WISPA] top 10 benefits of Wimax in 3.65ghz - my 2 cents
> Even thought this thread is a bit old, couldn't help but add my 2 cents > (as there seems to be a resurgence of "puff" in this space) > > > > DISCLAIMER: I am also a vendor of various WiMAX 802.16d systems - so feel > free to apply your necessary 'BS' filter > > > > > > Benefits of Wimax in 3.65ghz > > > > 1. Spectral efficiency ( 4.85 gross bp/hz ) On a six sector > > configuration with only 25mhz of spectrum, you can effectively deliver > > approx 20mb per sector or 120 mb / per pop, 240 mb when all 50 mhz is > > supported. Support for thousands of subscribers is possible off the same > > BSU. > > > > This isn't all too exciting, IMO - there are plenty of systems out there > that have similar (if not better) spectral efficiency characteristics as > to what the WiMAX 802.16d standard offers...also, with the uncertainties > of 3650 licensing, which is, from an interference protection perspective, > not that much different that Part-15, higher order modulation schemes > don't do much in the presence of noise > > > > Case in point: Why does everyone keep using Canopy 900 MHz systems when > you can get an 802.11a OFDM-based down-converted system that delivers 3-4x > the throughput? Well, it's a matter of what's actually going to work in > the crowded 900 MHz band. > > > > > > 2. multiple vendor support ( currently you have Redline, Aperto, > > Airspan, Alvarion, all with FCC approved equipment ) > > > > The "concept" of interoperability is one of the most "oversold" features > of WiMAX which needs to be explained... > > > > Fictitious Scenario: > > > > Say I had deployed Brand A system for my business users, and in order to > enable VoIP services, I enable a variety of the more advanced MAC features > (rTP for my VoIP)...I set up a variety of service flows that are > customized to each user...blah blah blah > > > > Problem is, Brand A system, for whatever reason, didn't support UGS and a > few esoteric service flow / packet filtering features, but at the time, > I'm really not too concerned because (a) my customers don't demand UGS > from me right now and (b) the concept of "WiMAX interoperability" story > gives me the conclusion that if I really need UGS, I could just buy / > upgrade to Brand X system and retain all of my Brand A CPEs that I've > deployed. > > > > Now, 6 months later, I've deployed 50 CPE in the field, and business is > doing good...so good in fact that 2 customers want to upgrade to a > "premium" service that requires features not currently supported on Brand > A AP. Luckily, I have a "WiMAX" system so I go upgrade Brand A AP with > Brand X. Common sense would lead me to believe that Brand X would support > all of my CPE's features, plus supporting the enhanced feature of UGS that > I need > > > > Sorry, isn't going to work > > > > As things turn out, the only "interoperability" testing done between Brand > A CPEs and Brand X APs were done at the Best Effort feature set (basic > Ethernet connectivity)...additionally, Rf interoperability was done at a > 3.5 MHz channel size, and I've been running Brand A at 10 MHz to maximize > my throughput (oh, and Brand X only supports 3.5 MHz, 5 MHz & 7 MHz > channel sizes)...so to get this interoperability, I lose all of my rTP / > VoIP prioritization for my entire network, or I have to go out and replace > my 20 Brand A CPEs that are running VoIP with Brand X CPEs > > > > Oops > > > > What's the moral of the story? > > > > Ultimately, unless you're willing to run your network at the lowest common > denominator, you're basically buying into a proprietary system. > > > > 3. Better RF performance ( even with siso systems ) > > > > Better RF performance as compared to what? And in what vein? > > > > I can easily "slant" the argument the other way by bringing up an example > where a proprietary system outperforms WiMAX > > > > Noise Immunity: Are you saying that WiMAX has better noise immunity that > Canopy (OFDM vs. FSK...yeah right) > > NLOS: Are you saying that WiMAX can do better NLoS than 900 MHz? > > Urban Reflective NLOS: Are you saying that WiMAX can do better Urban NLoS > than a MIMO-based 1024-FFT OFDM system? > > > > 4. NLOS performance ( OFDM+OFDMA = More difficult shots obtain link ) > > > > See above > > > > 5. Better QOS support, and service flows ( UGS, NRTPS, ETC can be ) > > > > There can be an argument made that the WiMAX MAC is much more > sophisticated than the Canopy / Alvarion VL / Trango / Tranzeo / CSMA-CA > systems on the market today...that said, don't forget that there is a > $$$COST$$$ for this sophistication...namely, you effectively lock yourself > into a "proprietary" implementation of your WiMAX system > > > > 6. Greater scalablity ( Single sector can support hundreds of > > subscribers, our platform supports 30,000 pps ) > > > > WiMAX in it's true tested and interoperable state maxes out at an > aggregate "throughput" range of ~10 Mbps per AP > > > > To get better performance (up to 20 Mbps / AP), I give up interoperability > > > > > > 7. Support for multiline VOIP out of box ( UGS + 30K PPS ) > > > > At the expense of interoperability > > > > 8. Sub 350 cpe shipping today ( in 100 packs, less with frame order > > commitments putting your cost sub 300 ) > > > > Ubiquiti Lightstations are sub-$100 > > Tranzeos / Deliberant / whatever are in the $100-200 range > > Motorola Canopy / Alvarion is in the $200-300 range > > > > Oh, and they (just like WiMAX) are basically proprietary > > > > 9. Carrier class systems vs Wisp class ( True 99.999% uptime solutions > > available for base station equipment, reducing downtime and truck rolls > > ) > > > > Carrier Class = $10k APs > > If you're willing to spend $10k for an AP - you can get a proprietary > 'WISP' system that has all the "carrier-class" features of "WiMAX" > > > > 10. Carrier class network management systems that simplify provisioning > > and management of subscribers and base stations. > > > > Lol...I find this amusing...as the WiMAX specification "overcomplicates" > the provisioning process, so you now have the need to purchase a system to > simplify provisioning so it will work like a Canopy / Trango / Tranzeo / > Alvarion =) > > > > Supply and Demand at its best =/ > > > > That said, if you are still interested in WiMAX after this "cold dose of > reality," we have plenty of radios in stock =) > > > > -Charles > > > > > -------------------------------------------------------------------------------- > WISPA Wants You! 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