I'm often asked if WiMax will replace Wi-Fi: In fact, I received such an email this morning. Here's the answer I sent in reply.
WiMax and 802.11n (and related standards) are somewhat unrelated. Wi-Fi is a local area network technology; WiMax (whether fixed, nomadic, or mobile) are wide-area network technologies.
Wi-Fi will continue to evolve as the best way to spread a network over an office or home or small area in which a cloud of service is needed. WiMax will probably evolve as a great replacement, alternative, or complement to fixed wired and mobile wireless services. That is, instead of an ADSL line or T-1 line, you might have a WiMax receiver on your roof or an antenna in your window. Instead of a cell phone that uses 3G to carry video or a cell data card for accessing a 3G network, you might have a WiMax-equipped laptop or phone.
Wi-Fi is a local distribution tool to push bits among users connected nearby; with many Wi-Fi base stations using the same name, you can build seamless coverage on a college campus, city park, or corporate campus. While it's being used for metro-scale deployment, that's because it's the best worst solution. It's not designed for that purpose, but everyone already has a Wi-Fi adapter, the technology works in unlicensed spectrum avoiding that issue, and it's highly commodified making parts cheap across the supply chain for consumers, vendors, and network builders.
Right now, you can get WiMax or WiMax-like fixed broadband pretty readily in most major U.S. cities and in a lot of urban and rural areas worldwide. It's very competitive in performance over shorter distances when you get to or over T1 or E1 speeds (roughly 1.5 Mbps each way). Several providers in the US already compete in some cities, and offer incentives like 24 to 48 hours from order to live access and free antennas and receivers with long-term contracts. Switching from a T1 to the equivalent of two T1s over fixed WiMax is often about the same price--sometimes a little less, sometimes a little more.
Mobile WiMax has a tougher row to hoe here in the U.S. as spectrum is scarce in the bands that are most likely for it to use: a few carriers own most of the desirable bandwidth. This means that even if it's financially viable and Intel rolls out WiMax adapters in laptops (as they plan to), you still have to find spectrum to offer service. A "mobile" WiMax base station can offer fixed, nomadic (a movable receiver that's static while in use), and mobile service.
Fixed WiMax has an easier time of it because it's primarily a point-to-multipoint, mostly line of sight service, and thus the sweet spot of lower frequencies needed for ubiquitous, seamless mobile coverage aren't as critical. There will be WiMax for unlicensed frequencies, and there's potentially some reserved spectrum in many countries and regions, including Europe, that could be put to use for mobile or fixed service.
That's the long answer. The short answer is that Wi-Fi and WiMax will continue down somewhat different paths because they serve different purposes. If WiMax ascends as a better means of faster, metropolitan access, Wi-Fi's importance in that role will dim. But WiMax isn't affordable or sensible as a campus-wide service yet, and it's unlikely to ever metamorphose into a Wi-Fi competitor.
Glenn
As a Service provider in the process of designing and deploying metro area Wireless Mesh systems in 2 cities, let me offer the following ref. WiMax & WiFi.
Initially, WiFI and WiMAX will operate together providing totally different levels of access for the WAN and WLAN markets.
We feel that WiFi will dominate both the Campus/Enterprise Wireless LAN and the Metro Area Networks major Thoroghfares (More where WiMAX fits latter).
What I mean by that is as follows:
In most markets, at least in the East, we have these things called trees with foliage that will play hell with any approved WiMAX products ability to delive a consistant quality signal over a Metro market. Works very nicely in a T-1 replacement scenario when we know where the customer is and can deploy a PTMP radio that has line of site or NLOS. This is not real WAN coverage much less mobile coverage.
Unfortunately the Licensed 2.5GHz spectrum (lowest approved by the WiMAX forum), the main players are planning to use, does not work consitently & effectively (high enough bandwidth and a lack of coverage) across a metro area. We know this in that we have played (in a controlled environment-our campus)with 2.4GHz in various (power level) scenarios (emulating a 2.5GHz scenario)and found it lacking in a PTMP deployment when it comes up against a tree.
When the WiMAX forum (and the FCC) approves the 700MHz (or even one of the new 1700-2100MHz being auctioned) spectrums for WiMAX use we will all have something of value.
WiFi in a Mesh format will lead with and provide coverage on major thoroughfares, business districts and high crime areas in these cities to allow the Service Provider to maximize their commercial coverage and the Cities (as anchors) to be able to provide true high bandwidth in major market areas as well.
Keep in mind one fundamental point with WiFi Mesh products-THESE ARE PRIMARILY OUTDOOR COVERAGE PRODUCTS, that can provide some indoor coverage. Most providers have been negligent in not pointing this out to the municipals they deal with-allowing them to go down this road of promising their residence coverage in their homes. This will cause long term problems for these cities and our Mesh markets.
These Wireless Mesh systems provide us with excellent coverage operating under the Canopy and delivering maximum bandwidth (1-6Mbps) to each subscriber operating outdoors in these key markets.
Where WiMAX comes in nicely is as follows:
Fixed WiMAX (802.16 2004) will be deployed in a Backhaul support mode initially, delivering both High Bandwidth links (Gateways) to feed our Mesh Nodes (like Canopy is doing for Earthlink) as well as deliver very high speed Point to Point links to key customers premise. If we leverage the PTMP capabilities of WiMAX we may be able to do both the above with one WIMAX Base System.
Of key interest to the Cities is delivering Wireless services to its residence-which will also use the Fixed WiMAX solution or one of the newer 5.8GHz QoS/OFDM based radios like Trango/Proxim or Solectek-as long as there is LOS to these customers. These newer radios are shipping today and are very cost effective in deploying anywhere from 20-45Mbps of service from a Base Station to a fixed site. Trango has a OFDM ready CPE Radio/Antenna for under $197 which is very strong in the home access area.
What I am not sure about here is the value of WiMAX 802.16e (Mobile) systems. With the rapid development of 802.11 (series) products and improvements in QoS/Bandwidth/security, and if the big chip players would let go of the 802.11n standard and allow Airgo's MIMO products to rule, we'd have a big threat to any Mobile WiMAX products.
In addition I feel the newer CellCO systems (3 & 4G) Data services will eventually cause problems for the WiMAX Mobile services when they fight over the remaining Nationwide and Rural Narrowband services outside of the Metro area markets covered by WiFi Mesh products. In addition when the CellCo's finally realize the above and agree to allow convergence (using one of the newer convergence products like DiVitas or the new UMA based systems)WiMAX mobile may have to fight to survive.
That is if Qualcomm (o others) do not stop all development and the release of some of the WiMAX products with its patents.
In summary, WiFi with its ubiquitous low cost 802.11a/b/g access devices, in play today, will continue to dominate the Metro Area based on the newer multiple (4-6) radio Mesh systems supported by Fixed WiMAX products.
When convergence occurs and or the FCC releases these newer 700MHZ and below spectrum the entire market will change.
Amen.
Jacomo