Software defined radios will open new routes for WiMAX
In the developed mobile world, WiMAX will have to live alongside several other technologies, and consumers will increasingly want to be able to roam seamlessly across different networks according to cost and availability - especially if open access models start to take off in earnest. This will place new momentum behind the bid to make multimode devices more complex, and yet cheaper and less power hungry.
Packing more and more radios on to a single chip is one approach, as pursued by Qualcomm (though no support for WiMAX yet). A stage beyond that comes the software programmable processor, which can be tweaked in software, by the handset maker or operator, to support a flexible combination of network connections. Sandbridge Technologies this week announced its contribution to this nascent market, with its SB3500, a 65nm reprogrammable software-based baseband processor, which can be adapted to LTE, HSPA, WiMAX, W-CDMA, Wi-Fi, GPS and the mobile TV standard DVB-H.
The processor is entirely software-based, and points to the vision of a fully cognitive radio in future - a single radio that can move intelligently between different networks, according to parameters such as cost or signal strength.
Because the platform is programmable, cellphone makers can use a single architecture to support phones with different combinations of radios, reducing their costs. Sandbridge's technology will also reduce the number of chips needed in a phone, which should cut cost, time to market and complexity. The company claims the cost savings can amount to 15% across design and production, and the figure could grow as consumers look for more and more functions to be packed into one low power unit.
Another advantage that Sandbridge claims for its technology is that handset makers can respond more quickly to standards changes - such as the next wave of 802.16e, or even the shift to 802.16m - testing and adding new functions rapidly in software rather than waiting for the chipmaker to deliver upgraded hardware. Changes in standards can also be easily accommodated, so operators could move to new networks even before standards are finalized, with reduced risk.
As for competition, there are other start-ups, such as Sweden's Coresonic, in this field, and ST-NXP Wireless has some advanced software defined technology, from the NXP side of the group, but most of the majors are nowhere near to market readiness with programmable basebands yet.
As for more conventional multimode devices, ABI Research, contrary to many market assumptions, believes many carriers will adopt a mixture of the two OFDM-based systems, which share many similarities. The company forecasts that 2009 will see the introduction of dual-mode WiMAX/LTE chipsets for devices.
"Some mobile operators are showing interest in dual-mode chipsets," said ABI principal analyst Philip Solis. "And they are backing it with cash. Vodafone, for example, has a foot in both WiMAX and LTE camps. They will use LTE in industrialized regions, and WiMAX in developing nations. In Japan, KDDI may deploy LTE on its own, but as an investor (along with Intel and others) in WiMAX operator UQ Communications, KDDI has an interest in both standards."
Looking ahead to full cognitive radios - which actually sense wireless traffic to make intelligent decisions about using spectrum - Intel hosted a workshop last week in conjunction with European research institute IMEC. The chip giant believes the FCC's recent decision to open up the white spaces in broadcast spectrum will light a new fire under cognitive radio work and offer WiMAX a new opportunity. Some early work on interference avoidance in the spaces was undertaken by 802.16 study groups.
Among companies represented at the workshop were Alcatel-Lucent, Alvarion, Marvell, Motorola, Nokia and Qualcomm and IMEC aims to build prototype hardware soon, geared to next generation WiMAX and LTE networks in licensed bands, as well as to various technologies for license-exempt white spaces.
Cognitive radios would "have more direct pay-off to the incumbent operators and some form of this probably will begin to appear in next generation broadband standards such as WiMAX 2 [802.16m] and LTE," said Kevin Kahn, director of Intel's communications technology lab. He also believes the white spaces will be a good area to test the new technology at relatively low cost and risk.
