WiMax crisis

A growing number of operators in emerging and developed markets alike have announced plans to develop WiMAX networks, and proponents of the technology, such as Motorola's director of wireless broadband in the region, Noel Kirkaldy, believe the opportunity is immense. "This technology is starting to appeal to everyone and has no longer become just one technology, it has evolved to become a suite of technologies," Kirkaldy states. "We are driving scale with the technology and the offer of wireless broadband is the most important role in the short term," he adds.

 

On the surface it thus appears that the mobile version of WiMAX, a technology that has arrived six or seven years after the introduction of WCDMA, has the wind beneath its wings and is set for take-off. Ericsson, however, has another view of the technology, and rather than just state the position, the equipment manufacturer went and ceased the development of its own mobile WiMAX solution, believing company resources could be more effectively used elsewhere.

"We do think that WiMAX can be an option for fixed wireless access, but that is a niche application," states Andreas Hessler, Ericsson VP of Networks in the Middle East. "Therefore we have chosen not to develop our own products. But we do have partner products, which are then suited for that kind of fixed wireless application, but they are not well suited for indoor coverage," he adds.

As far as Ericsson is concerned, WiMAX as a standard continues to have a number of technical limitations that make it unsuitable for indoor broadband use. With respect to the fixed version of the technology, Revision D, Hessler says that if one compares the performance of this standard with that of a HSPDA base station today, WiMAX is far behind. "I don't think WiMAX was developed to target the same segment. It was targeted at the fixed wireless segment, and then of course they have improved the standard going from the D version to the E version. They have optimised it a bit more for indoor use, but still we would say that there are several technical drawbacks with the standard," Hessler states.

He identifies that a very high overhead in the standard exists, which he describes as a short cut that results in the wastage of 30% of the spectrum, and is not really optimum. "In WCDMA, the equivalent overhead is less than 1%," Hessler asserts. WiMAX also utilises OFDM technology, which Hessler suggests has been subject to much hype, though issues still remain with respect to its peak average."The other disadvantage of WiMAX is that it is not really optimised for voice, it is only optimised for broadband," Hessler states. "And sometimes you hear the WiMAX industry saying that HSPA or WCDMA is not optimised for voice whereas WiMAX is optimised for broadband, which is not entirely true. It is easy to think that by optimising for a narrow band application you lose the broadband capability, which is not really the case."

Hessler goes on to assert that the difference in suitability for voice or broadband comes with respect to the number of channels available. "In WCDMA you can divide this channel into 256 sub-channels because voice is very narrow band, it does not require so much capacity. In WiMAX you can divide it into 32 and that makes a huge difference, as today voice is 90% of the revenues [of telecoms operators] so that makes a WiMAX operator's business case very difficult to make money from," he contends.