'M' is for microwave

Does anyone remember what the "M" in Wimax stands for? Right, it stands for "microwave" (as in Worldwide Interoperability for Microwave Access). When the Wimax Forum was established in 2001, nobody expected that this young organization would be challenging the powerful mobile telephony industry in less than a few years.

The beginning of the 21st century saw a consolidation in residential broadband internet demand in most developed countries, but the high cost of deployment for the technologies available at the time (fiber and DSL) reduced competition. Fixed broadband wireless was not an alternative, since the spectrum and equipment needed to operate such a service were extremely expensive. Then came the Wimax Forum, created to drive the almost dead licensed fixed broadband wireless market.

What almost nobody remembers is that the first specification adopted by the Wimax Forum was IEEE 802.16-2001, which targeted wireless links in the 10-66 GHz range. This initial specification was subsequently updated to include applications under 11 GHz, the much-awaited fixed broadband wireless access solution that, years later, would get the surname "mobile" thanks to the IEEE 802.16e specification.

After almost ten years of existence, we can say the Wimax Forum has been very successful in the establishment of an interoperability program that has allowed many new companies to enrich this new ecosystem, bringing life to the broadband wireless market. We can even affirm LTE development has considerably benefited from much of the Wimax Forum's effort, since many operators and vendors committed to LTE today acquired invaluable technical know-how and market experience when playing the Wimax card.

But where did that 10-66 GHz specification go? So-called WirelessMAN-SC (Single Carrier) has silently survived all the 802.16 revisions, being present in the last edition published in May 2009. Nevertheless, the microwave backhaul market, as it is known today, is far from any standardization effort. Is there room for a "Wireless Interoperability for Microwave Backhaul" (WiMB) initiative focused on generating the same benefits for microwave that Wimax has guaranteed to the access network?

De facto standardization

Years ago, when microwave links were predominantly TDM-based, they were considered to be just an ancillary part of the base station equipment. Therefore, the links were bundled by big vendors like Ericsson, Nokia Siemens Networks and NEC with the rest of the RAN equipment. But IP is bringing some kind of democracy to the telecom market, generating new business opportunities for smaller players that can beat the big players via the innovation path.

Setting aside the more recent 60-GHz and E-band solutions, if we look at the traditional 6-38 GHz bands, we will see most vendors offering almost the same top PHY features (256 QAM in 56-MHz channel), so technological competition is reduced to configuration options (all-indoor, all-outdoor or split mount) and TDM support implementation (pseudowires, native support or packet based scheduling). Functionality is so similar between vendors that many of them are already relying on commercial baseband chipsets to manufacture their products, the way that 3G and Wimax vendors do. Microwave vendors have reached a "de facto" standardization - which is positive, but not nearly enough.

On the other side we have operators with growing needs for transport capacity and cost optimization. They are forwarding these needs in the form of price pressure to microwave vendors. These vendors are beginning to get concerned about the direction of the market and wonder what their next move will be (apart from more marketing efforts).

WiMB is a move worth considering, not least because a potential interoperability process would be much easier than it is with mobile Wimax because the test cases are much fewer for a point-to-point, always-on, stationary technology. Would not WiMB be instrumental for operators and vendors to benefit from a really powerful ecosystem?

Esteban Monturus is a market analyst for Europe and backhaul at Maravedis
 

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