SAN JOSE, Calif. — Intel Corp. provided the first details of its reconfigurable radio architecture this week at the Software-Defined Radio Forum, where the company described an array of processors that will implement a range of physical layer and media-access control combinations.
In its first public discussion of its plans since Intel's chief technology officer Patrick Gelsinger revealed an intent to pursue reconfigurable radio at last year's Intel Developer Forum, Intel made it clear that its approach will differ from most other companies at the workshop. Rather than relying on programmable logic, Intel researcher Jeffrey Schiffer said Monday (Jan. 20) that the company's architecture will use a heterogeneous array of processors. Some will be general-purpose DSPs, and others will be tuned to process particular algorithms. Schiffer said the individual processors will be of intermediate complexity, between an FPGA and a modest CPU.
The processors are not bused, but rather are connected through a mesh that emphasizes nearest-neighbor relationships. This both offers a natural implementation for data flow organizations and reduces the power and signal integrity issues that come with long interconnect lines.
The mesh of processors is terminated on two sides by an array of I/O engines, with one array serving as an input device and the other serving as output. In front of the input processors resides a switchable array of analog front-ends — and, presumably, antennas — allowing the entire system to hop gracefully between frequency bands. Different analog front-ends provide different pre-filtering and signal capture/conversion. Behind the output array lives a collection of various media-access controller (MAC) devices.
Transparent configuration
Intel conceives the architecture as a solution to the problem of highly mobile digital appliances that must move not only from cell to cell, but from protocol to protocol and band to band in order to maintain connectivity. In operation, the proposed Intel device would continually query its environment to determine what services were available. It would then switch on the appropriate antenna and analog front-end combination to connect to the service, and configure out of the processor array an appropriate PHY/MAC layer implementation for that standard. This process would be transparent to the user, except for permission and billing issues.
Intel researchers have estimated that such a configurable array approach would be considerably less efficient, in both real estate and power, than a hard-wired PHY/MAC solution, or even two of them. But when the number of PHY/MAC combinations that must be supported reaches three, the Intel approach breaks even with dedicated engines. Above that number, the array is more efficient.
Thus Intel suggested that reconfigurable radio devices of the future will not challenge single-provider terminals. Rather, they would have a major role when the terminal is mobile and must move freely between numerous incompatible wireless network services.
