WiMAX may represent the "future" of wireless broadband connectivty, but it will not succeed without the support of many in the WiMAX Forum working with vendor companies. The WiMAX Forum is dedicated to making the WiMAX wireless communications standard a commercial reality and ensuring that WiMAX products will seamlessly work with each other.

The promise of broadband wireless access has existed for almost as long as cellular networks. Previous efforts at providing broadband wireless services have failed for various reasons, even though supported by a variety of well-funded equipment vendors. Generally, failure can be attributed to the lack of standardization and an excess of unique, proprietary solutions, both of which prevented a commonality of components for low-cost solutions. The failure of any effort to provide broadband wireless access can generally be traced to two factors, the cost and the risk of a proposed solution.

Since each broadband supplier had its own technology solution, dozens of different development programs were spawned to create different transceivers and baseband sections in each case. There was no economy of scale, as each program inevitably proposed multiple, expensive components with non-recurring-engineering (NRE) costs at each level that needed to be amortized as part of the development program. In addition to the hardware, each unique solution also called for a parallel software-development program to create unique firmware and interface software for operation, provisioning, and maintenance. These practices typically led to high equipment prices for the network operators. It should be remembered that even though these operators were well-funded, this didn't mean their investors were in business to lose money or take a chance on unproven technology.

Another key cost consideration was the fact that proprietary head-end radio solutions required proprietary customer premise equipment (CPE). Operators would be forced to supply (and likely subsidize) this equipment. The upshot was that all these costs associated with the lack of standardization eventually resulted in an untenable business case for network operators. The market of end users simply didn't have demand for broadband wireless (fixed or mobile) at prices that would make the entire venture worthwhile.

The majority of the equipment vendors selling high-cost, mid-1990s radios were startup companies. Network operators were understandably reticent to choose—and therefore be committed to— a single vendor's solution, especially when these were companies without previous histories. The possibility of supply interruptions, reliability problems with new technology, and the potential failure of a given supplier to stay in business were all factors that caused operators to delay their decisions to build out networks. In the end, very few operators were willing to be "captive" to a single vendor; the risk was simply too high.

Unlike industries that don't learn from their own mistakes, communications companies and the vendors that develop their networks are notoriously sensitive to reliving mistakes, especially when recent and painfully fresh in their minds. Standardization (i.e., interoperability) was clearly recognized as the key to fulfilling a broadband wireless dream, so the WiMAX Forum and its member companies work to ensure that service providers have choices, resulting in competition, better pricing, and less risk. This standardization drives down costs— both in terms of development (reuse of standard chip sets and associated reference designs) and ongoing component costs (economies of scale on a few parts, versus low volumes on numerous custom components). Risk is also mitigated through standardization because no operator is captive to a single vendor; and just as important, end-user equipment can be purchased directly by that user, instead of being supplied by the network operator. When costs are reasonable and risks are reduced, a profitable business case for the all members of the supply chain can be realized and the dream of true broadband wireless becomes a realistic goal.

The requirement for economies of scale and standardized equipment works its way all the way down to the component level. To that end, the need for component commonality has been a key part of TriQuint Semiconductor's WiMAX product-development philosophy. For example, high channel selectivity is critical to the front-end performance of both fixed and mobile WiMAX systems, implying the importance of the front end filter. In many cases, the spectrum allocated globally for WiMAX applications is precariously close to spectrum allocated for other applications. For example, there is no bandwidth buffer between the US WCS and satellite radio bands at 2.3 GHz. Because of the closely spaced frequency allocations and diversity of applications, there will be a need for superheterodyne transceiver solutions in the foreseeable future. Because of the need of highly selective filters in such transceiver achitectures, TriQuint Semiconductor has developed a broad portfolio of intermediate-frequency (IF) surface-acoustic-wave (SAW) filters for WiMAX applications, while also trying to maintain an economy of scale that will support economical WiMAX solutions.

Pursuing the goal of component commonality, TriQuint's engineering team has worked with key members of the WiMAX Forum (www.wimaxforum.org) and their design engineers to steer designs toward common IFs for WiMAX transceivers. In part because of these efforts, the industry has mainly converged to a handful of IF solutions at 380, 398, 456, 580, and 810 MHz. Although the idea of an ideal IF based on available mixers, local oscillators (LOs), analog-to-digital-converter (ADCs), and other components might have led to a single IF as the solution, this may not have been the most practical choice in terms of long-term WiMAX product development, and thus the multiple IF choices.