During the ISSCC 2012 conference Intel presented their first prototype of what can be called WoS – Wireless or Wi-Fi on Silicon (or Wireless-on-Chip). Researchers from Intel Labs managed to integrate a radio transceiver capable of operating in the 2.4GHz band into a dual-core Atom SoC (think Medfield) also including a DDR3 controller, PCIe interfaces, etc. Intel claims the radio delivered excellent results even when the PC is in full operation. While it doesn’t yet support 5GHz operation, 802.11n compliant 40MHz bandwidth can already be achieved.
Integrating a traditionally analog RF transceiver into a digital circuit is not exactly easy. It requires accurate transistor models and many spins during development until desireable performance is achieved. Another challenge is varying supply voltage and worse inductors as a result from new process technologies. Naturally, varying power on pins has a bad effect on the clearness of the radio signal. Furthermore, every processor has noisy digital and analog circuits which can have an adverse effect on radio performance. All these factors led Intel to develop a digital transmitter.
The prototype codenamed Rosepoint was manufactured at the 32nm node, which is where the majority of Intel’s chips are currently manufactured. The researchers point out, that due to the integration of a digital power amplifier the performance can be improved similar to how performance of processors improve with new manufacturing processes. Conventional analog RF circuits generally exhibit worse performance characteristics when moving to smaller CMOS structures.
Rosepoint will not become a shipping product in this form, but it should be expected that Intel is working on a Atom SoC integrating WiFi to improve their competitive position. According to Intel the integrated Wi-Fi radio should enable lower power operation, which is very desired in the mobile space.