WiMax d vs. e: The Difference a Letter Makes

Computerworld - The emergence of the WiMax standards has spurred tremendous interest from operators seeking to deploy next-generation, high-performing, cost-effective broadband wireless networks. However, the availability of 802.16e and 802.16d as two different and incompatible iterations of the WiMax standards has in some cases added confusion to the operator's investment decisions.

WiMax refers to both the 802.16d and 802.16e standards, which IEEE said supports a variety of applications and network solutions. The WiMax label refers to a defined subset of technology specifications from the 802.16d and 802.16e standards called "profiles."

Often referred to as the mobile standard, 802.16e not only introduces mobility to broadband wireless specifications, but it also provides enhanced performance even in fixed and nomadic environments. Below I have outlined several reasons why 802.16e is the true future of WiMax.

Not Backward Compatible

Operators seeking to make a WiMax investment must first recognize that 802.16e is not backward compatible with 802.16d. While some 802.16d vendors propose base station equipment with additional hardware complexity or software programmability to allow a switch to 802.16e, this will not impact any 802.16d end-user devices already deployed. These 802.16d end-user devices will not operate within an 802.16e network and the imperative for low-cost end-user devices makes it prohibitive to introduce additional hardware to attempt an upgrade to 802.16e compliance. Adding upgrade capability to the base station may also result in a large cost penalty.

Additionally, an operator who deploys 802.16d and then attempts to roll in 802.16e equipment at a later date will be disadvantaged by having to split the available licensed spectrum between the two technologies. Without a true upgrade path from 802.16d to 802.16e and the necessity to preserve spectrum to support network growth, 802.16e provides the best long-term protection for an operator's WiMax investments.

Lower Cost

As the broadband wireless market continues to grow, the industry should expect to benefit from cost reductions enabled by volume deployments and economies of scale. Portable and mobile applications have a very strong track record for accelerating volume, therefore it is expected that mobile deployments of 802.16e will bring cost points down below solutions engineered solely for fixed applications using 802.16d.

Additionally, major chip set manufacturers have announced that 802.16e will be the premier standard for WiMax applications, pointing to a substantial embedded base of consumer products with 802.16e support. These same chip sets used in laptops and handhelds can be leveraged in the manufacturing of indoor- and outdoor-fixed customer premise equipment. It becomes quickly apparent that 802.16e offers the critical advantage of allowing the operator to ride a downward trending cost curve.