Wireless Systems Design

WiMAX Progress Not Slowed By Competition

WiMAX, one of many broadband wireless standards, is finally making progress—despite the massive competition.

For those of us who monitor the progress of the various new wireless technologies, it always seems like it takes decades for any new standard to take off and hit its intended stride. Okay, maybe not decades, but it sure seems like it. I have watched Wi-Fi, Bluetooth, and ultra wideband (UWB) slog through their various stages of development and each seems to be doing okay—especially Wi-Fi and Bluetooth, which are well established. UWB is still "emerging," but is finally finding some niches to dominate. And now, at last, I can report that WiMAX, the promising broadband wireless solution, seems to be making its way into the mainstream. WiMAX overlaps with lots of other wireless technologies, but, like most of those technologies, it appears that it may find its place.

A New Brand of Wireless

WiMAX is shorthand for Wireless Interoperability of Microwave Access, the general name given to radios that comply with the IEEEs 802.16 standard. This standard defines a broadband wireless technology that was designed initially to deliver fast Internet data access wirelessly to compete with cable and DSL (digital subscriber line) services. It is finding its way in that competitive arena, especially in rural areas that are not well served by existing broadband connections. That first standard is called 802.16d or 802.16-2004 or fixed WiMAX. A later standard, known as 802.16e or 802.16-2005, is called mobile WiMAX. The mobile version is robust enough to deliver very high-speed data connections—even in moving vehicles—and could even compete with cell phone service.

With the standards in place and lots of companies already making chips and boxes, we have all wondered why there hasn’t been some WiMAX services we could subscribe to. The answer is a complex one, dominated by issues like competition from other services, the need for big time capital investments in the infrastructure, and the general lack of suitable spectrum. But now it seems like these problems are being solved. Two recent occurrences make me, and lots of others, believe that WiMAX is finally a done deal.

First, Sprint Nextel has stepped up and stuck their neck out a long way to offer WiMAX in many U.S. markets in late 2007 and 2008. The company is spending about $3 billion over the next two years to build basestations and related back haul to handle the service once it is launched. And Sprint Nextel is working with handset and basestation vendors to make sure that end user products are available to use the services.

Second, an early player in WiMAX, Clearwire, just recently completed an initial public offering that brought in about $600 million to fund the build out of their proposed networks. But will all this investment pay off? The question of return on investment is an age-old business question, so we will have to wait and see. But at least Sprint and Clearwire are taking the chance. Hopefully this will kick off additional investments in WiMAX that will make it successful.

Competition Or Not?

WiMAX was designed from the ground up to deliver really fast data over significant distances, yet be robust and reliable even in non-line of sight (NLOS) situations that usually prevent microwave operation. But because WiMAX uses OFDM (Orthogonal Frequency Division Multiplexing), it is fast and robust. And the standard provides a large number of bandwidth, modulation, and speed options to fit almost any situation. The outer limits are roughly 70 Mbit/s+ at a range of up to about 30 miles. That could only be achieved with a solid line of sight path with maximum modulation. More commonly, the service is expected to deliver from a minimum of about 1 Mbit/s to 10 Mbit/s over a shorter range up to, say, several miles around the base station. Such a service is going to be a real benefit to those in smaller towns where the only Internet service is dial-up. There are literally millions of them in the U.S., but there are millions more in large and small underdeveloped countries. With WiMAX, an entire telecom system can be built around WiMAX to provide not only high-speed Internet access, but also wireless phone service with VoIP (Voice Over Internet Protocol). No buried wires or wires strung on hundreds or thousands of poles.

But how will WiMAX fare in the U.S., where we already have lots of other wireless options in place? That is the big question. In the major markets, WiMAX will end up competing against 3G cell phone service and Wi-Fi. So how does it stack up?

Consider 3G wireless services first. These are being rolled out in almost every major city in the U.S. Verizon and Sprint Nextel are upgrading their CDMA (Code-Division Multiple Access) networks to the latest versions of Qualcomm's EV-DO high-speed wireless services. Even the newer, higher speed Rev A and Rev B services are seeing some action. Then in the GSM world, AT&T and T-Mobile are building their UMTS (universal mobile telecommunications system) WCDMA networks with the high speed HSDPA (High Speed Downlink Packet Access) option. These services are available in handsets and in cards that plug into laptop slots. Speeds from just below 1 Mbit/s to about 7 Mbits/s are possible, depending on the environment and the link robustness. That is tough competition. If you really need to be connected to e-mail and other Internet services, this is a good, reliable option that is available almost everywhere.

Next, think about the competition from Wi-Fi. With hot spots and other access points available almost everywhere and Wi-Fi built into just about every laptop made, who needs WiMAX? And think of the hundreds of metro Wi-Fi mesh networks that have been built over the past few years. You can get e-mail and Internet operability virtually everywhere nowadats. And more and more, users are taking advantage of the VoIP services now available over Wi-Fi networks. Can WiMAX compete? Maybe.

First off, WiMAX is probably a bit more forgiving of bad links because it uses OFDM. So it can probably deliver a bit higher speed more reliably than 3G or Wi-Fi. And it can do it over a longer range. But that is offset somewhat by the fact that WiMAX uses higher microwave frequencies (2.4 GHz and 5.8 GHz in the U.S.). 3G cell phones use lower frequencies that do travel a bit farther for comparable conditions. And WiMAX was designed for mobile operation where Wi-Fi was not. So it is possible that what you will see is both WiMAX and Wi-Fi built into laptops to maintain connections everywhere at maximum possible data rates. And you could also see WiMAX/Wi-Fi VoIP handsets that offer voice services as well as fast data.

As for cost of service, I suspect WiMAX service will be on par with what you might pay for a 3G card for your laptop, but a bit more than a regular Wi-Fi connection. Services providers will have to make it competitive to make it work.

Will WiMAX Make It?

I’ll give it about a 70/30 percent chance. And that is in the U.S. It does overlap with other available services, but its technology gives it some advantages that make it desirable and could allow it to work where other methods do not. And there is lots of action to improve what is there now. Tropos Networks, for example, just announced its MetroMesh NG WiMAX solution that offers WiMAX, Wi-Fi and 4.9 GHz wireless networking. Chip makers like Infineon and Sequans have some nifty new ICs that make WiMAX cheap and practical. Infineon's new SMART WiMAX chip supports both IEEE 802.16e mobile WiMAX as well as 802.11b/g Wi-Fi. Sequans has its new SQN1130, which incorporates 2x2 MIMO (multiple-in, multiple-out) to give WiMAX even greater range, data rate, and reliability.

Europe is going for WiMAX in a big way as well, despite the fuss by the major cell phone carriers about the competition. The rest of the world is also finding WiMAX a great solution for remote wireless and phone needs. Most of the current WiMAX equipment makers are getting most of their income from sales outside the U.S. But hopefully that will change.

So while WiMAX has completed one more step in its evolution to recognized wireless option, we’ll still have to wait and see—however long that may be.

TAGS: Mobile
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