Back in the early 2000s, the WiMAX Forum developed a new wireless technology known as WiMAX —short for Worldwide Interoperability for Microwave Access. The new technology was standardized by the IEEE as 802.16. And through the mid-2000s it was continuously updated. The WiMAX Forum promoted the technology and established a certification program for products to ensure interoperability. WiMAX got lots of attention and many thought it would be the next Wi-Fi.
WiMAX’s original target was apparently wireless Internet access, an alternative to cable TV and DSL, especially in rural areas where good Internet access was not typically available. It was also used for microwave backhaul. In addition, it was considered a prime candidate for 4G cellular beyond CDMA and GSM/HSPA. But then along came Long Term Evolution (LTE). While WiMAX did make it in the 4G cell phone business thanks to Sprint and some carriers outside the U.S., most other and all the major carriers adopted LTE. Eventually even Sprint has been changing its networks over to LTE and phasing out its WiMAX phone systems. The last will go off line sometime this year. Basically what happened to WiMAX is LTE.
Yet, WiMAX is still around. It is still widely used for wireless Internet access especially outside the U.S. There are hundreds of WiMAX installations worldwide, but not so many in the U.S. One main wireless Internet Service Provider (WISP) is Clearwire or CLEAR, a division of Sprint that still widely deploys WiMAX throughout the U.S.
In case you do not know or just forgot, WiMAX is an OFDM technology. It uses 256 subcarriers and can be adjusted to use bandwidths of 1.25, 5, 10, or 20 MHz. The original standard was for the 10 to 66 GHz range, but later versions added the 2 to 11 GHz range. Most WiMAX installations seem to use the 2.3 to 2.5 and 3.5 GHz bands. Backhaul uses the higher frequencies. Most WiMAX services use time division duplex (TDD) that does not require the dual spectrum assignments of frequency division duplex (FDD) as used in most LTE installations.
As for data rate, speeds up to 1 Gb/s are possible with the latest versions with high-count MIMO. A typically quoted spec is up to 70 Mb/s at 50 km. Not bad. Most WISPs deliver speeds in the 1 to 5 Mb/s even in non-line of sight instances up to several km.
WiMAX is alive and well, but currently living in the shadow of LTE. It is a great wireless technology that has found its own niche. It could really become an alternative technology for the Internet of Things (IoT) as that movement comes into its own. Anyway, it is worth considering. At least its fate is positive unlike another OFDM-based wireless technology, IEEE 802.22. But that’s another story.